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Sample records for genome-wide linkage search

  1. A genome-wide search for linkage to renal function phenotypes in West Africans with type 2 diabetes.

    PubMed

    Chen, Guanjie; Adeyemo, Adebowale A; Zhou, Jie; Chen, Yuanxiu; Doumatey, Ayo; Lashley, Kerrie; Huang, Hanxia; Amoah, Albert; Agyenim-Boateng, Kofi; Eghan, Benjamin A; Okafor, Godfrey; Acheampong, Joseph; Oli, Johnnie; Fasanmade, Olufemi; Johnson, Thomas; Rotimi, Charles

    2007-03-01

    Reduced renal function often is a major consequence of diabetes and hypertension. Although several indices of renal function (eg, creatinine clearance) are clearly heritable and show linkage to several genomic regions, the specific underlying genetic determinants are still being sought. The purpose of this study is to conduct a genome-wide search for regions linked to 3 renal function phenotypes, serum creatinine, creatinine clearance, and glomerular filtration rate (GFR), in persons with type 2 diabetes. A genome-wide panel of 372 autosomal short tandem repeat markers at an average spacing of 9 centimorgan were typed in 691 patients with type 2 diabetes (321 sib pairs and 36 half-sib pairs) in an affected sib pair study in West Africa. Linkage analysis was conducted with the 3 phenotypes by using a multipoint variance components linkage method. Creatinine clearance showed higher logarithm of odds (LOD) score than the other 2 phenotypes. Linkage to creatinine clearance was observed on chromosomes 16 (marker D16S539, LOD score of 3.56, empirical P = 0.0001), 17 (D17S1298, LOD score of 2.08, empirical P = 0.0018), and 7 (D7S1818, LOD score of 1.84, nominal P = 0.00181, empirical P = 0.0022). Maximum LOD scores for serum creatinine were observed on chromosomes 10 (D10S1432, LOD score of 2.53, empirical P = 0.0001) and 3 (D3S2418, LOD score of 2.21, empirical P = 0.0003) and for GFR on chromosomes 6 (D6S1040, LOD score of 2.08, empirical P = 0.0001) and 8 (D8S256, LOD score of 1.80, empirical P = 0.0001). Several of these results are replications of significant findings from other genome scans. A genome-wide scan for serum creatinine, creatinine clearance, and GFR in a West African sample showed linkage regions that may harbor genes influencing variation in these phenotypes. Potential candidate genes in these regions that have been implicated in diabetic nephropathy and/or renal damage in models of hypertension include CYBA (or P22PHOX) (16q24), NOX1 (10q22), and NOX3

  2. Genome-wide high-density SNP linkage search for glioma susceptibility loci: results from the Gliogene Consortium.

    PubMed

    Shete, Sanjay; Lau, Ching C; Houlston, Richard S; Claus, Elizabeth B; Barnholtz-Sloan, Jill; Lai, Rose; Il'yasova, Dora; Schildkraut, Joellen; Sadetzki, Siegal; Johansen, Christoffer; Bernstein, Jonine L; Olson, Sara H; Jenkins, Robert B; Yang, Ping; Vick, Nicholas A; Wrensch, Margaret; Davis, Faith G; McCarthy, Bridget J; Leung, Eastwood Hon-chiu; Davis, Caleb; Cheng, Rita; Hosking, Fay J; Armstrong, Georgina N; Liu, Yanhong; Yu, Robert K; Henriksson, Roger; Melin, Beatrice S; Bondy, Melissa L

    2011-12-15

    Gliomas, which generally have a poor prognosis, are the most common primary malignant brain tumors in adults. Recent genome-wide association studies have shown that inherited susceptibility plays a role in the development of glioma. Although first-degree relatives of patients exhibit a two-fold increased risk of glioma, the search for susceptibility loci in familial forms of the disease has been challenging because the disease is relatively rare, fatal, and heterogeneous, making it difficult to collect sufficient biosamples from families for statistical power. To address this challenge, the Genetic Epidemiology of Glioma International Consortium (Gliogene) was formed to collect DNA samples from families with two or more cases of histologically confirmed glioma. In this study, we present results obtained from 46 U.S. families in which multipoint linkage analyses were undertaken using nonparametric (model-free) methods. After removal of high linkage disequilibrium single-nucleotide polymorphism, we obtained a maximum nonparametric linkage score (NPL) of 3.39 (P = 0.0005) at 17q12-21.32 and the Z-score of 4.20 (P = 0.000007). To replicate our findings, we genotyped 29 independent U.S. families and obtained a maximum NPL score of 1.26 (P = 0.008) and the Z-score of 1.47 (P = 0.035). Accounting for the genetic heterogeneity using the ordered subset analysis approach, the combined analyses of 75 families resulted in a maximum NPL score of 3.81 (P = 0.00001). The genomic regions we have implicated in this study may offer novel insights into glioma susceptibility, focusing future work to identify genes that cause familial glioma.

  3. Genome-wide high-density SNP linkage search for glioma susceptibility loci: results from the Gliogene Consortium

    PubMed Central

    Shete, Sanjay; Lau, Ching C; Houlston, Richard S; Claus, Elizabeth B; Barnholtz-Sloan, Jill; Lai, Rose; Il’yasova, Dora; Schildkraut, Joellen; Sadetzki, Siegal; Johansen, Christoffer; Bernstein, Jonine L; Olson, Sara H; Jenkins, Robert B; Yang, Ping; Vick, Nicholas A; Wrensch, Margaret; Davis, Faith G; McCarthy, Bridget J; Leung, Eastwood Hon-chiu; Davis, Caleb; Cheng, Rita; Hosking, Fay J; Armstrong, Georgina N; Liu, Yanhong; Yu, Robert K; Henriksson, Roger; Consortium, The Gliogene; Melin, Beatrice S; Bondy, Melissa L

    2011-01-01

    Gliomas, which generally have a poor prognosis, are the most common primary malignant brain tumors in adults. Recent genome-wide association studies have demonstrated that inherited susceptibility plays a role in the development of glioma. Although first-degree relatives of patients exhibit a two-fold increased risk of glioma, the search for susceptibility loci in familial forms of the disease has been challenging because the disease is relatively rare, fatal, and heterogeneous, making it difficult to collect sufficient biosamples from families for statistical power. To address this challenge, the Genetic Epidemiology of Glioma International Consortium (Gliogene) was formed to collect DNA samples from families with two or more cases of histologically confirmed glioma. In this study, we present results obtained from 46 U.S. families in which multipoint linkage analyses were undertaken using nonparametric (model-free) methods. After removal of high linkage disequilibrium SNPs, we obtained a maximum nonparametric linkage score (NPL) of 3.39 (P=0.0005) at 17q12–21.32 and the Z-score of 4.20 (P=0.000007). To replicate our findings, we genotyped 29 independent U.S. families and obtained a maximum NPL score of 1.26 (P=0.008) and the Z-score of 1.47 (P=0.035). Accounting for the genetic heterogeneity using the ordered subset analysis approach, the combined analyses of 75 families resulted in a maximum NPL score of 3.81 (P=0.00001). The genomic regions we have implicated in this study may offer novel insights into glioma susceptibility, focusing future work to identify genes that cause familial glioma. PMID:22037877

  4. A high-density SNP genome-wide linkage search of 206 families identifies susceptibility loci for chronic lymphocytic leukemia

    PubMed Central

    Sellick, Gabrielle S.; Goldin, Lynn R.; Wild, Ruth W.; Slager, Susan L.; Ressenti, Laura; Strom, Sara S.; Dyer, Martin J. S.; Mauro, Francesca R.; Marti, Gerald E.; Fuller, Stephen; Lyttelton, Matthew; Kipps, Thomas J.; Keating, Michael J.; Call, Timothy G.; Catovsky, Daniel

    2007-01-01

    Chronic lymphocytic leukemia (CLL) and other B-cell lymphoproliferative disorders display familial aggregation. To identify a susceptibility gene for CLL, we assembled families from the major European (ICLLC) and American (GEC) consortia to conduct a genome-wide linkage analysis of 101 new CLL pedigrees using a high-density single nucleotide polymorphism (SNP) array and combined the results with data from our previously reported analysis of 105 families. Here, we report on the combined analysis of the 206 families. Multipoint linkage analyses were undertaken using both nonparametric (model-free) and parametric (model-based) methods. After the removal of high linkage disequilibrium SNPs, we obtained a maximum nonparametric linkage (NPL) score of 3.02 (P = .001) on chromosome 2q21.2. The same genomic position also yielded the highest multipoint heterogeneity LOD (HLOD) score under a common recessive model of disease susceptibility (HLOD = 3.11; P = 7.7 × 10−5), which was significant at the genome-wide level. In addition, 2 other chromosomal positions, 6p22.1 (corresponding to the major histocompatibility locus) and 18q21.1, displayed HLOD scores higher than 2.1 (P < .002). None of the regions coincided with areas of common chromosomal abnormalities frequently observed in CLL. These findings provide direct evidence for Mendelian predisposition to CLL and evidence for the location of disease loci. PMID:17687107

  5. Genome-wide search for breast cancer linkage in large Icelandic non-BRCA1/2 families

    PubMed Central

    2010-01-01

    Introduction: A significant proportion of high-risk breast cancer families are not explained by mutations in known genes. Recent genome-wide searches (GWS) have not revealed any single major locus reminiscent of BRCA1 and BRCA2, indicating that still unidentified genes may explain relatively few families each or interact in a way obscure to linkage analyses. This has drawn attention to possible benefits of studying populations where genetic heterogeneity might be reduced. We thus performed a GWS for linkage on nine Icelandic multiple-case non-BRCA1/2 families of desirable size for mapping highly penetrant loci. To follow up suggestive loci, an additional 13 families from other Nordic countries were genotyped for selected markers. Methods: GWS was performed using 811 microsatellite markers providing about five centiMorgan (cM) resolution. Multipoint logarithm of odds (LOD) scores were calculated using parametric and nonparametric methods. For selected markers and cases, tumour tissue was compared to normal tissue to look for allelic loss indicative of a tumour suppressor gene. Results: The three highest signals were located at chromosomes 6q, 2p and 14q. One family contributed suggestive LOD scores (LOD 2.63 to 3.03, dominant model) at all these regions, without consistent evidence of a tumour suppressor gene. Haplotypes in nine affected family members mapped the loci to 2p23.2 to p21, 6q14.2 to q23.2 and 14q21.3 to q24.3. No evidence of a highly penetrant locus was found among the remaining families. The heterogeneity LOD (HLOD) at the 6q, 2p and 14q loci in all families was 3.27, 1.66 and 1.24, respectively. The subset of 13 Nordic families showed supportive HLODs at chromosome 6q (ranging from 0.34 to 1.37 by country subset). The 2p and 14q loci overlap with regions indicated by large families in previous GWS studies of breast cancer. Conclusions: Chromosomes 2p, 6q and 14q are candidate sites for genes contributing together to high breast cancer risk. A

  6. Meta-Analysis of Genome-Wide Linkage Scans of Attention Deficit Hyperactivity Disorder

    PubMed Central

    Zhou, Kaixin; Dempfle, Astrid; Arcos-Burgos, Mauricio; Bakker, Steven C.; Banaschewski, Tobias; Biederman, Joseph; Buitelaar, Jan; Castellanos, F.Xavier; Doyle, Alysa; Ebstein, Richard P.; Ekholm, Jenny; Forabosco, Paola; Franke, Barbara; Freitag, Christine; Friedel, Susann; Gill, Michael; Hebebrand, Johannes; Hinney, Anke; Jacob, Christian; Lesch, Klaus Peter; Loo, Sandra K.; Lopera, Francisco; McCracken, James T.; McGough, James J.; Meyer, Jobst; Mick, Eric; Miranda, Ana; Muenke, Maximilian; Mulas, Fernando; Nelson, Stanley F.; Nguyen, T.Trang; Oades, Robert D.; Ogdie, Matthew N.; Palacio, Juan David; Pineda, David; Reif, Andreas; Renner, Tobias J.; Roeyers, Herbert; Romanos, Marcel; Rothenberger, Aribert; Schäfer, Helmut; Sergeant, Joseph; Sinke, Richard J.; Smalley, Susan L.; Sonuga-Barke, Edmund; Steinhausen, Hans-Christoph; van der Meulen, Emma; Walitza, Susanne; Warnke, Andreas; Lewis, Cathryn M; Faraone, Stephen V.; Asherson, Philip

    2010-01-01

    Genetic contribution to the development of attention deficit hyperactivity disorder (ADHD) is well established. Seven independent genome-wide linkage scans have been performed to map loci that increase the risk for ADHD. Although significant linkage signals were identified in some of the studies, there has been limited replications between the various independent datasets. The current study gathered the results from all seven of the ADHD linkage scans and performed a Genome Scan Meta Analysis (GSMA) to identify the genomic region with most consistent linkage evidence across the studies. Genome-wide significant linkage (PSR=0.00034, POR=0.04) was identified on chromosome 16 between 64 and 83 Mb. In addition there are nine other genomic regions from the GSMA showing nominal or suggestive evidence of linkage. All these linkage results may be informative and focus the search for novel ADHD susceptibility genes. PMID:18988193

  7. Heritability and genome-wide linkage scan of subjective happiness.

    PubMed

    Bartels, Meike; Saviouk, Viatcheslav; de Moor, Marleen H M; Willemsen, Gonneke; van Beijsterveldt, Toos C E M; Hottenga, Jouke-Jan; de Geus, Eco J C; Boomsma, Dorret I

    2010-04-01

    Causes of individual differences in happiness, as assessed with the Subjective Happiness Scale, are investigated in a large of sample twins and siblings from the Netherlands Twin Register. Over 12,000 twins and siblings, average age 24.7 years (range 12 to 88), took part in the study. A genetic model with an age by sex design was fitted to the data with structural equation modeling in Mx. The heritability of happiness was estimated at 22% for males and 41% in females. No effect of age was observed. To identify the genomic regions contributing to this heritability, a genome-wide linkage study for happiness was conducted in sibling pairs. A subsample of 1157 offspring from 441 families was genotyped with an average of 371 micro-satellite markers per individual. Phenotype and genotype data were analyzed in MERLIN with multipoint variance component linkage analysis and age and sex as covariates. A linkage signal (logarithm of odds score 2.73, empirical p value 0.095) was obtained at the end of the long arm of chromosome 19 for marker D19S254 at 110 cM. A second suggestive linkage peak was found at the short arm of chromosome 1 (LOD of 2.37) at 153 cM, marker D1S534 (empirical p value of .209). These two regions of interest are not overlapping with the regions found for contrasting phenotypes (such as depression, which is negatively associated with happiness). Further linkage and future association studies are warranted.

  8. Genome-wide linkage in Utah autism pedigrees

    PubMed Central

    Allen-Brady, K; Robison, R; Cannon, D; Varvil, T; Villalobos, M; Pingree, C; Leppert, MF; Miller, J; McMahon, WM; Coon, H

    2014-01-01

    Genetic studies of autism over the past decade suggest a complex landscape of multiple genes. In the face of this heterogeneity, studies that include large extended pedigrees may offer valuable insight, as the relatively few susceptibility genes within single large families may be more easily discerned. This genome-wide screen of 70 families includes 20 large extended pedigrees of 6–9 generations, 6 moderate-sized families of 4–5 generations, and 44 smaller families of 2–3 generations. The Center for Inherited Disease Research (CIDR) provided genotyping using the Illumina Linkage Panel 12, a 6K single nucleotide polymorphism (SNP) platform. Results from 192 subjects with an Autism Spectrum Disorder (ASD), and 461 of their relatives revealed genome-wide significance on chromosome 15q, with three possibly distinct peaks: 15q13.1-q14 (HLOD=4.09 at 29,459,872bp); 15q14-q21.1 (HLOD=3.59 at 36,837,208bp); and 15q21.1-q22.2 (HLOD=5.31 at 55,629,733bp). Two of these peaks replicate previous findings. There were additional suggestive results on chromosomes 2p25.3-p24.1 (HLOD=1.87), 7q31.31-q32.3 (HLOD=1.97), and 13q12.11-q12.3 (HLOD=1.93). Affected subjects in families supporting the linkage peaks found in this study did not reveal strong evidence for distinct phenotypic subgroups. PMID:19455147

  9. Genome-wide linkage-disequilibrium profiles from single individuals.

    PubMed

    Lynch, Michael; Xu, Sen; Maruki, Takahiro; Jiang, Xiaoqian; Pfaffelhuber, Peter; Haubold, Bernhard

    2014-09-01

    Although the analysis of linkage disequilibrium (LD) plays a central role in many areas of population genetics, the sampling variance of LD is known to be very large with high sensitivity to numbers of nucleotide sites and individuals sampled. Here we show that a genome-wide analysis of the distribution of heterozygous sites within a single diploid genome can yield highly informative patterns of LD as a function of physical distance. The proposed statistic, the correlation of zygosity, is closely related to the conventional population-level measure of LD, but is agnostic with respect to allele frequencies and hence likely less prone to outlier artifacts. Application of the method to several vertebrate species leads to the conclusion that >80% of recombination events are typically resolved by gene-conversion-like processes unaccompanied by crossovers, with the average lengths of conversion patches being on the order of one to several kilobases in length. Thus, contrary to common assumptions, the recombination rate between sites does not scale linearly with distance, often even up to distances of 100 kb. In addition, the amount of LD between sites separated by <200 bp is uniformly much greater than can be explained by the conventional neutral model, possibly because of the nonindependent origin of mutations within this spatial scale. These results raise questions about the application of conventional population-genetic interpretations to LD on short spatial scales and also about the use of spatial patterns of LD to infer demographic histories. Copyright © 2014 by the Genetics Society of America.

  10. A genome-wide linkage study of individuals with high scores on NEO personality traits.

    PubMed

    Amin, N; Schuur, M; Gusareva, E S; Isaacs, A; Aulchenko, Y S; Kirichenko, A V; Zorkoltseva, I V; Axenovich, T I; Oostra, B A; Janssens, A C J W; van Duijn, C M

    2012-10-01

    The NEO-Five-Factor Inventory divides human personality traits into five dimensions: neuroticism, extraversion, openness, conscientiousness and agreeableness. In this study, we sought to identify regions harboring genes with large effects on the five NEO personality traits by performing genome-wide linkage analysis of individuals scoring in the extremes of these traits (>90th percentile). Affected-only linkage analysis was performed using an Illumina 6K linkage array in a family-based study, the Erasmus Rucphen Family study. We subsequently determined whether distinct, segregating haplotypes found with linkage analysis were associated with the trait of interest in the population. Finally, a dense single-nucleotide polymorphism genotyping array (Illumina 318K) was used to search for copy number variations (CNVs) in the associated regions. In the families with extreme phenotype scores, we found significant evidence of linkage for conscientiousness to 20p13 (rs1434789, log of odds (LOD)=5.86) and suggestive evidence of linkage (LOD >2.8) for neuroticism to 19q, 21q and 22q, extraversion to 1p, 1q, 9p and12q, openness to 12q and 19q, and agreeableness to 2p, 6q, 17q and 21q. Further analysis determined haplotypes in 21q22 for neuroticism (P-values = 0.009, 0.007), in 17q24 for agreeableness (marginal P-value = 0.018) and in 20p13 for conscientiousness (marginal P-values = 0.058, 0.038) segregating in families with large contributions to the LOD scores. No evidence for CNVs in any of the associated regions was found. Our findings imply that there may be genes with relatively large effects involved in personality traits, which may be identified with next-generation sequencing techniques.

  11. Genome-wide linkage scan of quantitative traits representing symptom dimensions in multiplex schizophrenia families.

    PubMed

    Ryu, Seunghyong; Won, Hong-Hee; Oh, Sohee; Kim, Jong-Won; Park, Taesung; Cho, Eun-Young; Cho, Youngah; Park, Dong Yeon; Lee, Yu-Sang; Kwon, Jun Soo; Hong, Kyung Sue

    2013-12-30

    Symptom dimensions of schizophrenia are likely to be the intermediate phenotypes under the control of disease-susceptibility genes, or separate traits related to disease-modifier genes. This study aimed to identify chromosomal loci linked to symptom dimensions of schizophrenia through genome-wide quantitative trait locus (QTL) linkage analysis. The study subjects consisted of 56 families with 183 members including 123 affected individuals. Symptom evaluations were performed on lifetime basis. Through principal component factor analysis, eight quantitative phenotypes representing symptom dimensions were identified. Genotyping was done for 6008 SNP markers, and genome-wide QTL linkage analysis was performed. No symptom dimension showed a significant linkage attaining genome-wide empirical thresholds. We observed seven regions yielding linkage signals attaining genome-wide empirical thresholds for suggestive linkage (NPL Z score = 2.78-3.49); chromosome 15q26.1 for 'non-paranoid delusion factor', 2p24.3 and 7q31.1 for 'prodromal impairment factor', 1q32.1, 9p21.3, and 9q31.2 for 'negative symptom factor', and 10p13 for 'disorganization factor'. Among these loci, chromosome 2p24.3 and 1q32.1 overlap with susceptibility loci of schizophrenia identified in our previous linkage studies. This study suggests the existence of genetic loci related to various clinical features of schizophrenia. Further genetic analyses for these dimensional phenotypes are warranted. © 2013 Published by Elsevier Ireland Ltd.

  12. A Genome-wide Quantitative Linkage Scan of Niacin Skin Flush Response in Families With Schizophrenia

    PubMed Central

    Lien, Yin-Ju; Huang, Sih-Syuan; Liu, Chih-Min; Hwu, Hai-Gwo; Faraone, Stephen V.; Tsuang, Ming T.; Chen, Wei J.

    2013-01-01

    Schizophrenia patients frequently display reduced niacin flush responses, and similar characteristics are also observed in their nonpsychotic relatives. This study aimed to identify loci influencing flush response to niacin in schizophrenia using genome-wide quantitative linkage scan. In a nationwide sample of families with at least 2 siblings affected with schizophrenia in each family, 115 families that had at least 2 affected siblings with information on the niacin skin test were subjected to quantitative trait loci linkage analysis, either involving affected individuals only or the whole family. Nonparametric linkage z (NPL-Z) scores were calculated for each of 386 microsatellite markers spaced at an average of 9-cM intervals. Niacin patches of 3 concentrations (0.001M, 0.01, and 0.1M) were applied to forearm skin, and the flush response was rated at 5, 10, and 15 minutes, respectively, with a 4-point scale. Determination of genome-wide empirical significance was implemented using 1000 simulated genome scans. One linkage peak attaining genome-wide significance was identified at chromosomal region 14q32.12 for 0.01M concentration at 5 minutes (NPL-Z scores = 3.39, genome-wide empirical P = .03) in affected individuals, and the corresponding linkage signal remained strong (NPL-Z scores = 2.87) for the analyses of the whole family. This locus is distinct from the chromosomal region identified in the previous genome-wide scan for the diagnosis of schizophrenia, and the signal was higher than the peak linkage signal in that study. These findings indicate that there might be modifier or susceptibility-modifier genes at 14q32.12 for schizophrenia-related attenuation of flush response to niacin. PMID:21653277

  13. Meta-analysis of 32 genome-wide linkage studies of schizophrenia

    PubMed Central

    Ng, MYM; Levinson, DF; Faraone, SV; Suarez, BK; DeLisi, LE; Arinami, T; Riley, B; Paunio, T; Pulver, AE; Irmansyah; Holmans, PA; Escamilla, M; Wildenauer, DB; Williams, NM; Laurent, C; Mowry, BJ; Brzustowicz, LM; Maziade, M; Sklar, P; Garver, DL; Abecasis, GR; Lerer, B; Fallin, MD; Gurling, HMD; Gejman, PV; Lindholm, E; Moises, HW; Byerley, W; Wijsman, EM; Forabosco, P; Tsuang, MT; Hwu, H-G; Okazaki, Y; Kendler, KS; Wormley, B; Fanous, A; Walsh, D; O’Neill, FA; Peltonen, L; Nestadt, G; Lasseter, VK; Liang, KY; Papadimitriou, GM; Dikeos, DG; Schwab, SG; Owen, MJ; O’Donovan, MC; Norton, N; Hare, E; Raventos, H; Nicolini, H; Albus, M; Maier, W; Nimgaonkar, VL; Terenius, L; Mallet, J; Jay, M; Godard, S; Nertney, D; Alexander, M; Crowe, RR; Silverman, JM; Bassett, AS; Roy, M-A; Mérette, C; Pato, CN; Pato, MT; Roos, J Louw; Kohn, Y; Amann-Zalcenstein, D; Kalsi, G; McQuillin, A; Curtis, D; Brynjolfson, J; Sigmundsson, T; Petursson, H; Sanders, AR; Duan, J; Jazin, E; Myles-Worsley, M; Karayiorgou, M; Lewis, CM

    2009-01-01

    A genome scan meta-analysis (GSMA) was carried out on 32 independent genome-wide linkage scan analyses that included 3255 pedigrees with 7413 genotyped cases affected with schizophrenia (SCZ) or related disorders. The primary GSMA divided the autosomes into 120 bins, rank-ordered the bins within each study according to the most positive linkage result in each bin, summed these ranks (weighted for study size) for each bin across studies and determined the empirical probability of a given summed rank (PSR) by simulation. Suggestive evidence for linkage was observed in two single bins, on chromosomes 5q (142-168 Mb) and 2q (103-134 Mb). Genome-wide evidence for linkage was detected on chromosome 2q (119-152 Mb) when bin boundaries were shifted to the middle of the previous bins. The primary analysis met empirical criteria for ‘aggregate’ genome-wide significance, indicating that some or all of 10 bins are likely to contain loci linked to SCZ, including regions of chromosomes 1, 2q, 3q, 4q, 5q, 8p and 10q. In a secondary analysis of 22 studies of European-ancestry samples, suggestive evidence for linkage was observed on chromosome 8p (16-33 Mb). Although the newer genome-wide association methodology has greater power to detect weak associations to single common DNA sequence variants, linkage analysis can detect diverse genetic effects that segregate in families, including multiple rare variants within one locus or several weakly associated loci in the same region. Therefore, the regions supported by this meta-analysis deserve close attention in future studies. PMID:19349958

  14. Genome-wide linkage analysis of blood pressure under locus heterogeneity

    PubMed Central

    Yang, Xinqun; Wang, Kai; Huang, Jian; Vieland, Veronica J

    2003-01-01

    We describe a method for mapping quantitative trait loci that allows for locus heterogeneity. A genome-wide linkage analysis of blood pressure was performed using sib-pair data from the Framingham Heart Study. Evidence of linkage was found on four markers (GATA89G08, GATA23D06, GATA14E09, and 049xd2) at a significance level of 0.01. Two of them (GATA14E09 and 049xd2) seem to overlap with linkage signals reported previously, while the other two are not linked to any known signals. PMID:14975146

  15. Genome-wide Linkage Screen in Familial Parkinson Disease Identifies Loci on Chromosomes 3 and 18

    PubMed Central

    Gao, Xiaoyi; Martin, Eden R.; Liu, Yutao; Mayhew, Gregory; Vance, Jeffery M.; Scott, William K.

    2009-01-01

    Parkinson disease (PD) is a complex, multifactorial neurodegenerative disease with substantial evidence for genetic risk factors. We conducted a genome-wide linkage screen of 5824 single-nucleotide polymorphisms in 278 families of European, non-Hispanic descent to localize regions that harbor susceptibility loci for PD. By using parametric and nonparametric linkage analyses and allowing for genetic heterogeneity among families, we found two loci for PD. Significant evidence for linkage was detected on chromosome 18q11 (maximum lod score [MLOD] = 4.1) and suggestive evidence for linkage was obtained on chromosome 3q25 (MLOD = 2.5). These results were strongest in families not previously screened for linkage, and simulation studies suggest that these findings are likely due to locus heterogeneity rather than random statistical error. The finding of two loci (one highly statistically significant) suggests that additional PD susceptibility genes might be identified through targeted candidate gene studies in these regions. PMID:19327735

  16. Meta-analysis of genome-wide linkage studies across autoimmune diseases

    PubMed Central

    Forabosco, Paola; Bouzigon, Emmanuelle; Ng, Mandy Y; Hermanowski, Jane; Fisher, Sheila A; Criswell, Lindsey A; Lewis, Cathryn M

    2009-01-01

    Autoimmune diseases are chronic disorders initiated by a loss of immunologic tolerance to self-antigens. They cluster within families, and patients may be diagnosed with more than one disease, suggesting pleiotropic genes are involved in the aetiology of different diseases. To identify potential loci, which confer susceptibility to autoimmunity independent of disease phenotype, we pooled results from genome-wide linkage studies, using the genome scan meta-analysis method (GSMA). The meta-analysis included 42 independent studies for 11 autoimmune diseases, using 7350 families with 18 291 affected individuals. In addition to the HLA region, which showed highly significant genome-wide evidence for linkage, we obtained suggestive evidence for linkage on chromosome 16, with peak evidence at 10.0–19.8 Mb. This region may harbour a pleiotropic gene (or genes) conferring risk for several diseases, although no such gene has been identified through association studies. We did not identify evidence for linkage at several genes known to confer increased risk to different autoimmune diseases (PTPN22, CTLA4), even in subgroups of diseases consistently found to be associated with these genes. The relative risks conferred by variants in these genes are modest (<1.5 in most cases), and even a large study like this meta-analysis lacks power to detect linkage. This study illustrates the concept that linkage and association studies have power to identify very different types of disease-predisposing variants. PMID:18781189

  17. Genome-wide Linkage Analyses of Quantitative and Categorical Autism Subphenotypes

    PubMed Central

    Liu, Xiao-Qing; Paterson, Andrew D.; Szatmari, Peter

    2008-01-01

    Background The search for susceptibility genes in autism and autism spectrum disorders (ASD) has been hindered by the possible small effects of individual genes and by genetic (locus) heterogeneity. To overcome these obstacles, one method is to use autism-related subphenotypes instead of the categorical diagnosis of autism since they may be more directly related to the underlying susceptibility loci. Another strategy is to analyze subsets of families that meet certain clinical criteria to reduce genetic heterogeneity. Methods In this study, using 976 multiplex families from the Autism Genome Project consortium, we performed genome-wide linkage analyses on two quantitative subphenotypes, the total scores of the reciprocal social interaction domain and the restricted, repetitive, and stereotyped patterns of behavior domain from the Autism Diagnostic Interview-Revised. We also selected subsets of ASD families based on four binary subphenotypes, delayed onset of first words, delayed onset of first phrases, verbal status, and IQ ≥ 70. Results When the ASD families with IQ ≥ 70 were used, a logarithm of odds (LOD) score of 4.01 was obtained on chromosome 15q13.3-q14, which was previously linked to schizophrenia. We also obtained a LOD score of 3.40 on chromosome 11p15.4-p15.3 using the ASD families with delayed onset of first phrases. No significant evidence for linkage was obtained for the two quantitative traits. Conclusions This study demonstrates that selection of informative subphenotypes to define a homogeneous set of ASD families could be very important in detecting the susceptibility loci in autism. PMID:18632090

  18. A GENOME-WIDE LINKAGE AND ASSOCIATION SCAN REVEALS NOVEL LOCI FOR AUTISM

    PubMed Central

    Weiss, Lauren A.; Arking, Dan E.

    2009-01-01

    Summary Although autism is a highly heritable neurodevelopmental disorder, attempts to identify specific susceptibility genes have thus far met with limited success 1. Genome-wide association studies (GWAS) using half a million or more markers, particularly those with very large sample sizes achieved through meta-analysis, have shown great success in mapping genes for other complex genetic traits (http://www.genome.gov/26525384). Consequently, we initiated a linkage and association mapping study using half a million genome-wide SNPs in a common set of 1,031 multiplex autism families (1,553 affected offspring). We identified regions of suggestive and significant linkage on chromosomes 6q27 and 20p13, respectively. Initial analysis did not yield genome-wide significant associations; however, genotyping of top hits in additional families revealed a SNP on chromosome 5p15 (between SEMA5A and TAS2R1) that was significantly associated with autism (P = 2 × 10−7). We also demonstrated that expression of SEMA5A is reduced in brains from autistic patients, further implicating SEMA5A as an autism susceptibility gene. The linkage regions reported here provide targets for rare variation screening while the discovery of a single novel association demonstrates the action of common variants. PMID:19812673

  19. A genome-wide linkage and association scan reveals novel loci for autism.

    PubMed

    Weiss, Lauren A; Arking, Dan E; Daly, Mark J; Chakravarti, Aravinda

    2009-10-08

    Although autism is a highly heritable neurodevelopmental disorder, attempts to identify specific susceptibility genes have thus far met with limited success. Genome-wide association studies using half a million or more markers, particularly those with very large sample sizes achieved through meta-analysis, have shown great success in mapping genes for other complex genetic traits. Consequently, we initiated a linkage and association mapping study using half a million genome-wide single nucleotide polymorphisms (SNPs) in a common set of 1,031 multiplex autism families (1,553 affected offspring). We identified regions of suggestive and significant linkage on chromosomes 6q27 and 20p13, respectively. Initial analysis did not yield genome-wide significant associations; however, genotyping of top hits in additional families revealed an SNP on chromosome 5p15 (between SEMA5A and TAS2R1) that was significantly associated with autism (P = 2 x 10(-7)). We also demonstrated that expression of SEMA5A is reduced in brains from autistic patients, further implicating SEMA5A as an autism susceptibility gene. The linkage regions reported here provide targets for rare variation screening whereas the discovery of a single novel association demonstrates the action of common variants.

  20. Genome-wide distribution of genetic diversity and linkage disequilibrium in elite sugar beet germplasm

    PubMed Central

    2011-01-01

    Background Characterization of population structure and genetic diversity of germplasm is essential for the efficient organization and utilization of breeding material. The objectives of this study were to (i) explore the patterns of population structure in the pollen parent heterotic pool using different methods, (ii) investigate the genome-wide distribution of genetic diversity, and (iii) assess the extent and genome-wide distribution of linkage disequilibrium (LD) in elite sugar beet germplasm. Results A total of 264 and 238 inbred lines from the yield type and sugar type inbreds of the pollen parent heterotic gene pools, respectively, which had been genotyped with 328 SNP markers, were used in this study. Two distinct subgroups were detected based on different statistical methods within the elite sugar beet germplasm set, which was in accordance with its breeding history. MCLUST based on principal components, principal coordinates, or lapvectors had high correspondence with the germplasm type information as well as the assignment by STRUCTURE, which indicated that these methods might be alternatives to STRUCTURE for population structure analysis. Gene diversity and modified Roger's distance between the examined germplasm types varied considerably across the genome, which might be due to artificial selection. This observation indicates that population genetic approaches could be used to identify candidate genes for the traits under selection. Due to the fact that r2 >0.8 is required to detect marker-phenotype association explaining less than 1% of the phenotypic variance, our observation of a low proportion of SNP loci pairs showing such levels of LD suggests that the number of markers has to be dramatically increased for powerful genome-wide association mapping. Conclusions We provided a genome-wide distribution map of genetic diversity and linkage disequilibrium for the elite sugar beet germplasm, which is useful for the application of genome-wide association

  1. Genome-wide linkage scan for psoriasis susceptibility loci in multiplex Tunisian families.

    PubMed

    Ammar, M; Bouchlaka-Souissi, C; Helms, C A; Zaraa, I; Jordan, C T; Anbunathan, H; Bouhaha, R; Kouidhi, S; Doss, N; Dhaoui, R; Ben Osman, A; Ben Ammar El Gaied, A; Marrakchi, R; Mokni, M; Bowcock, A M

    2013-03-01

    Psoriasis is a relapsing chronic inflammatory skin disease affecting all population groups, with a peak prevalence of 3% in northern European and Scandinavian caucasians. Epidemiological studies have implicated a genetic component to psoriasis. In the past 12 years multiple genome-wide linkage analyses have identified putative susceptibility loci on several chromosomes, with a major locus in the major histocompatibility complex region. To investigate the genetic basis of familial psoriasis in the Tunisian population using a genome-wide linkage scan in seven ultiplex psoriatic families from Tunisia. Following single nucleotide polymorphism (SNP) genotyping on the Affymetrix 10K SNP array, we performed nonparametric linkage (NPL) multipoint analyses to identify genotypes and obtain evidence for linkage with psoriasis across the genome. No chromosomal region gave consistent evidence for linkage, providing evidence for genetic heterogeneity in Tunisian psoriasis families. Significant evidence for linkage of psoriasis to chromosome 2p12 was seen in one family. We also identified several regions of tentative psoriasis linkage on chromosomes 2q, 4q, 6p, 11q, 12q, 9q and 13q. One family exhibiting suggestive evidence for linkage to 17q25 (PSORS2) was identified and all affected members harboured a p.Gly117Ser mutation in CARD14 (caspase recruitment domain family, member 14), recently reported to lead to psoriasis in a large family from the U.S.A. Our results support the genetic heterogeneity of psoriasis in the Tunisian population, provide confirmatory evidence for a novel psoriasis locus at chromosome 2p12 and reveal a psoriasis family with a mutation at PSORS2. © 2012 The Authors. BJD © 2012 British Association of Dermatologists.

  2. Genome-wide linkage analysis in families with infantile hypertrophic pyloric stenosis indicates novel susceptibility loci.

    PubMed

    Svenningsson, Anna; Söderhäll, Cilla; Persson, Sofia; Lundberg, Fredrik; Luthman, Holger; Chung, Eddie; Gardiner, Mark; Kockum, Ingrid; Nordenskjöld, Agneta

    2012-02-01

    Infantile hypertrophic pyloric stenosis (IHPS) is a common cause of upper gastrointestinal obstruction during infancy. A multifactorial background of the disease is well established. Multiple susceptibility loci including the neuronal nitric oxide synthase (NOS1) gene have previously been linked to IHPS, but contradictory results of linkage studies in different materials indicate genetic heterogeneity. To identify IHPS susceptibility loci, we conducted a genome-wide linkage analysis in 37 Swedish families. In regions where the Swedish material showed most evidence in favor of linkage, 31 additional British IHPS families were analyzed. Evidence in favor of significant linkage was observed in the Swedish material to two loci on chromosome 2q24 (non-parametric linkage (NPL) =3.77) and 7p21 (NPL=4.55). In addition, evidence of suggestive linkage was found to two loci on chromosome 6p21 (NPL=2.97) and 12q24 (NPL=2.63). Extending the material with British samples did not enhance the level of significance. Regions with linkage harbor interesting candidate genes, such as glucagon-like peptide-2 (GLP-2 encoded by the glucagon gene GCG), NOS1, motilin (MLN) and neuropeptide Y (NPY). The coding exons for GLP-2, and NPY were screened for mutations with negative results. In conclusion, we could confirm suggestive linkage to the region harboring the NOS1 gene and detected additional novel susceptibility loci for IHPS.

  3. A high-density SNP genome-wide linkage scan in a large autism extended pedigree.

    PubMed

    Allen-Brady, K; Miller, J; Matsunami, N; Stevens, J; Block, H; Farley, M; Krasny, L; Pingree, C; Lainhart, J; Leppert, M; McMahon, W M; Coon, H

    2009-06-01

    We performed a high-density, single nucleotide polymorphism (SNP), genome-wide scan on a six-generation pedigree from Utah with seven affected males, diagnosed with autism spectrum disorder. Using a two-stage linkage design, we first performed a nonparametric analysis on the entire genome using a 10K SNP chip to identify potential regions of interest. To confirm potentially interesting regions, we eliminated SNPs in high linkage disequilibrium (LD) using a principal components analysis (PCA) method and repeated the linkage results. Three regions met genome-wide significance criteria after controlling for LD: 3q13.2-q13.31 (nonparametric linkage (NPL), 5.58), 3q26.31-q27.3 (NPL, 4.85) and 20q11.21-q13.12 (NPL, 5.56). Two regions met suggestive criteria for significance 7p14.1-p11.22 (NPL, 3.18) and 9p24.3 (NPL, 3.44). All five chromosomal regions are consistent with other published findings. Haplotype sharing results showed that five of the affected subjects shared more than a single chromosomal region of interest with other affected subjects. Although no common autism susceptibility genes were found for all seven autism cases, these results suggest that multiple genetic loci within these regions may contribute to the autism phenotype in this family, and further follow-up of these chromosomal regions is warranted.

  4. Genome-wide estimation of linkage disequilibrium from population-level high-throughput sequencing data.

    PubMed

    Maruki, Takahiro; Lynch, Michael

    2014-08-01

    Rapidly improving sequencing technologies provide unprecedented opportunities for analyzing genome-wide patterns of polymorphisms. In particular, they have great potential for linkage-disequilibrium analyses on both global and local genetic scales, which will substantially improve our ability to derive evolutionary inferences. However, there are some difficulties with analyzing high-throughput sequencing data, including high error rates associated with base reads and complications from the random sampling of sequenced chromosomes in diploid organisms. To overcome these difficulties, we developed a maximum-likelihood estimator of linkage disequilibrium for use with error-prone sampling data. Computer simulations indicate that the estimator is nearly unbiased with a sampling variance at high coverage asymptotically approaching the value expected when all relevant information is accurately estimated. The estimator does not require phasing of haplotypes and enables the estimation of linkage disequilibrium even when all individual reads cover just single polymorphic sites. Copyright © 2014 by the Genetics Society of America.

  5. Genome-wide Linkage and Association Analysis of Cardiometabolic Phenotypes in Hispanic Americans

    PubMed Central

    Hellwege, Jacklyn N.; Palmer, Nicholette D.; Dimitrov, Latchezar; Keaton, Jacob M.; Tabb, Keri L.; Sajuthi, Satria; Taylor, Kent D.; Ng, Maggie C.Y.; Speliotes, Elizabeth K.; Hawkins, Gregory A.; Long, Jirong; Chen, Yii-Der Ida; Lorenzo, Carlos; Norris, Jill M.; Rotter, Jerome I.; Langefeld, Carl D.; Wagenknecht, Lynne E.; Bowden, Donald W.

    2016-01-01

    Linkage studies of complex genetic diseases have been largely replaced by Genome-Wide Association studies (GWAS), due in part to limited success in complex trait discovery. However, recent interest in rare and low-frequency variants motivates reexamination of family-based methods. In this study we investigated the performance of two-point linkage analysis for over 1.6 million SNPs combined with single variant association analysis to identify high impact variants which are both strongly linked and associated with cardiometabolic traits in up to 1 414 Hispanics from the Insulin Resistance Atherosclerosis Family Study (IRASFS). Evaluation of all 50 phenotypes yielded 83 557 000 LOD scores with 9 214 LOD scores ≥ 3.0, 845 ≥ 4.0, and 89 ≥ 5.0, with a maximal LOD score of 6.49 (rs12956744 in the LAMA1 gene for TNFα receptor 2). Twenty-seven variants were associated with p < 0.005 as well as having a LOD score > 4, including variants in the NFIB gene under a linkage peak with TNFα receptor 2 levels on chromosome 9. Linkage regions of interest included a broad peak (31Mb) on chromosome 1q with acute insulin response (max LOD = 5.37). This region was previously documented with type 2 diabetes in family-based studies, providing support for the validity of these results. Overall, we have demonstrated the utility of two-point linkage and association in comprehensive genome-wide array-based SNP genotypes. PMID:27535031

  6. Genome-wide linkage and association analysis of cardiometabolic phenotypes in Hispanic Americans.

    PubMed

    Hellwege, Jacklyn N; Palmer, Nicholette D; Dimitrov, Latchezar; Keaton, Jacob M; Tabb, Keri L; Sajuthi, Satria; Taylor, Kent D; Ng, Maggie C Y; Speliotes, Elizabeth K; Hawkins, Gregory A; Long, Jirong; Ida Chen, Yii-Der; Lorenzo, Carlos; Norris, Jill M; Rotter, Jerome I; Langefeld, Carl D; Wagenknecht, Lynne E; Bowden, Donald W

    2017-02-01

    Linkage studies of complex genetic diseases have been largely replaced by genome-wide association studies, due in part to limited success in complex trait discovery. However, recent interest in rare and low-frequency variants motivates re-examination of family-based methods. In this study, we investigated the performance of two-point linkage analysis for over 1.6 million single-nucleotide polymorphisms (SNPs) combined with single variant association analysis to identify high impact variants, which are both strongly linked and associated with cardiometabolic traits in up to 1414 Hispanics from the Insulin Resistance Atherosclerosis Family Study (IRASFS). Evaluation of all 50 phenotypes yielded 83 557 000 LOD (logarithm of the odds) scores, with 9214 LOD scores ⩾3.0, 845 ⩾4.0 and 89 ⩾5.0, with a maximal LOD score of 6.49 (rs12956744 in the LAMA1 gene for tumor necrosis factor-α (TNFα) receptor 2). Twenty-seven variants were associated with P<0.005 as well as having an LOD score >4, including variants in the NFIB gene under a linkage peak with TNFα receptor 2 levels on chromosome 9. Linkage regions of interest included a broad peak (31 Mb) on chromosome 1q with acute insulin response (max LOD=5.37). This region was previously documented with type 2 diabetes in family-based studies, providing support for the validity of these results. Overall, we have demonstrated the utility of two-point linkage and association in comprehensive genome-wide array-based SNP genotypes.

  7. Genome-Wide Linkage Disequilibrium in Nine-Spined Stickleback Populations

    PubMed Central

    Yang, Ji; Shikano, Takahito; Li, Meng-Hua; Merilä, Juha

    2014-01-01

    Variation in the extent and magnitude of genome-wide linkage disequilibrium (LD) among populations residing in different habitats has seldom been studied in wild vertebrates. We used a total of 109 microsatellite markers to quantify the level and patterns of genome-wide LD in 13 Fennoscandian nine-spined stickleback (Pungitius pungitius) populations from four (viz. marine, lake, pond, and river) different habitat types. In general, high magnitude (D’ > 0.5) of LD was found both in freshwater and marine populations, and the magnitude of LD was significantly greater in inland freshwater than in marine populations. Interestingly, three coastal freshwater populations located in close geographic proximity to the marine populations exhibited similar LD patterns and genetic diversity as their marine neighbors. The greater levels of LD in inland freshwater compared with marine and costal freshwater populations can be explained in terms of their contrasting demographic histories: founder events, long-term isolation, small effective sizes, and population bottlenecks are factors likely to have contributed to the high levels of LD in the inland freshwater populations. In general, these findings shed new light on the patterns and extent of variation in genome-wide LD, as well as the ecological and evolutionary factors driving them. PMID:25122668

  8. Meta-analyses of genome-wide linkage scans of anxiety-related phenotypes

    PubMed Central

    Webb, Bradley T; Guo, An-Yuan; Maher, Brion S; Zhao, Zhongming; van den Oord, Edwin J; Kendler, Kenneth S; Riley, Brien P; Gillespie, Nathan A; Prescott, Carol A; Middeldorp, Christel M; Willemsen, Gonneke; de Geus, Eco JC; Hottenga, Jouke-Jan; Boomsma, Dorret I; Slagboom, Eline P; Wray, Naomi R; Montgomery, Grant W; Martin, Nicholas G; Wright, Margie J; Heath, Andrew C; Madden, Pamela A; Gelernter, Joel; Knowles, James A; Hamilton, Steven P; Weissman, Myrna M; Fyer, Abby J; Huezo-Diaz, Patricia; McGuffin, Peter; Farmer, Anne; Craig, Ian W; Lewis, Cathryn; Sham, Pak; Crowe, Raymond R; Flint, Jonathan; Hettema, John M

    2012-01-01

    Genetic factors underlying trait neuroticism, reflecting a tendency towards negative affective states, may overlap genetic susceptibility for anxiety disorders and help explain the extensive comorbidity amongst internalizing disorders. Genome-wide linkage (GWL) data from several studies of neuroticism and anxiety disorders have been published, providing an opportunity to test such hypotheses and identify genomic regions that harbor genes common to these phenotypes. In all, 11 independent GWL studies of either neuroticism (n=8) or anxiety disorders (n=3) were collected, which comprised of 5341 families with 15 529 individuals. The rank-based genome scan meta-analysis (GSMA) approach was used to analyze each trait separately and combined, and global correlations between results were examined. False discovery rate (FDR) analysis was performed to test for enrichment of significant effects. Using 10 cM intervals, bins nominally significant for both GSMA statistics, PSR and POR, were found on chromosomes 9, 11, 12, and 14 for neuroticism and on chromosomes 1, 5, 15, and 16 for anxiety disorders. Genome-wide, the results for the two phenotypes were significantly correlated, and a combined analysis identified additional nominally significant bins. Although none reached genome-wide significance, an excess of significant PSRP-values were observed, with 12 bins falling under a FDR threshold of 0.50. As demonstrated by our identification of multiple, consistent signals across the genome, meta-analytically combining existing GWL data is a valuable approach to narrowing down regions relevant for anxiety-related phenotypes. This may prove useful for prioritizing emerging genome-wide association data for anxiety disorders. PMID:22473089

  9. A genome-wide search for quantitative trait loci influencing substance dependence vulnerability in adolescence.

    PubMed

    Stallings, Michael C; Corley, Robin P; Hewitt, John K; Krauter, Kenneth S; Lessem, Jeffrey M; Mikulich, Susan K; Rhee, Soo Hyun; Smolen, Andrew; Young, Susan E; Crowley, Thomas J

    2003-06-05

    This study describes results from a genome-wide search for quantitative trait loci (QTL) influencing substance dependence vulnerability in adolescence. We utilized regression-based multipoint (and single-point) QTL mapping procedures designed for selected sibpair samples. Selected sibling pairs included 250 proband-sibling pairs from 192 families. Clinical probands (13-19 years of age) were drawn from consecutive admissions to substance abuse treatment facilities in the Denver metropolitan area; siblings of probands ranged in age from 12 to 25 years. In addition to the selected sample, a community-based sample of 3676 adolescents and young adults were utilized to define a clinically-significant, heritable, age- and sex-normed index of substance dependence vulnerability-a priori and independent of our linkage results. Siblings and their parents were genotyped for 374 STR micro-satellite markers distributed across the 22 autosomes (average inter-marker distance=9.2 cM). Non-parametric single-point linkage results indicated 17 markers on 11 chromosomes with nominally significant tests of linkage; six markers with LOD scores greater than 1.0 and one marker (D3S1614) with a LOD score of 2.2. Multipoint mapping corroborated two locations and provided preliminary evidence for linkage to regions on chromosome 3q24-25 (near markers D3S1279 and D3S1614) and chromosome 9q34 (near markers D9S1826 and D9S1838).

  10. Genome-wide linkage analysis for human longevity: Genetics of Healthy Ageing Study

    PubMed Central

    Beekman, Marian; Blanché, Hélène; Perola, Markus; Hervonen, Anti; Bezrukov, Vladyslav; Sikora, Ewa; Flachsbart, Frederieke; Christiansen, Lene; De Craen, Anton J.M.; Kirkwood, Tom B.L.; Rea, I. Meave; Poulain, Michel; Robine, Jean-Marie; Stazi, Maria Antonietta; Passarino, Giuseppe; Deiana, Luca; Gonos, Efstathios S.; Valensin, Silvana; Paternoster, Lavinia; Sørensen, Thorkild I.A.; Tan, Qihua; Helmer, Quinta; Van den Akker, Erik B.; Deelen, Joris; Martella, Francesca; Cordell, Heather J.; Ayers, Kristin L.; Vaupel, James W.; Törnwall, Outi; Johnson, Thomas E.; Schreiber, Stefan; Lathrop, Mark; Skytthe, Axel; Westendorp, Rudi G.J.; Christensen, Kaare; Gampe, Jutta; Nebel, Almut; Houwing-Duistermaat, Jeanine J.; Slagboom, P. Eline; Franceschi, Claudio

    2013-01-01

    Summary Clear evidence exists for heritability of human longevity, and much interest is focused on identifying genes associated with longer lives. To identify such longevity alleles, we performed the largest genome-wide linkage scan thus far reported. Linkage analyses included 2118 nonagenarian Caucasian sibling pairs that have been enrolled in fifteen study centers of eleven European countries as part of the Genetics of Healthy Ageing (GEHA) project. In the joint linkage analyses we observed four regions that show linkage with longevity; chromosome 14q11.2 (LOD=3.47), chromosome 17q12-q22 (LOD=2.95), chromosome 19p13.3-p13.11 (LOD=3.76) and chromosome 19q13.11-q13.32 (LOD=3.57). To fine map these regions linked to longevity, we performed association analysis using GWAS data in a subgroup of 1,228 unrelated nonagenarian and 1,907 geographically matched controls. Using a fixed effect meta-analysis approach, rs4420638 at the TOMM40/APOE/APOC1 gene locus showed significant association with longevity (p-value=9.6 × 10−8). By combined modeling of linkage and association we showed that association of longevity with APOEε4 and APOEε2 alleles explain the linkage at 19q13.11-q13.32 with p-value=0.02 and p-value=1.0 × 10−5, respectively. In the largest linkage scan thus far performed for human familial longevity, we confirm that the APOE locus is a longevity gene and that additional longevity loci may be identified at 14q11.2, 17q12-q22 and 19p13.3-p13.11. Since the latter linkage results are not explained by common variants, we suggest that rare variants play an important role in human familial longevity. PMID:23286790

  11. Genome-wide association and linkage analyses localize a progressive retinal atrophy locus in Persian cats.

    PubMed

    Alhaddad, Hasan; Gandolfi, Barbara; Grahn, Robert A; Rah, Hyung-Chul; Peterson, Carlyn B; Maggs, David J; Good, Kathryn L; Pedersen, Niels C; Lyons, Leslie A

    2014-08-01

    Hereditary eye diseases of animals serve as excellent models of human ocular disorders and assist in the development of gene and drug therapies for inherited forms of blindness. Several primary hereditary eye conditions affecting various ocular tissues and having different rates of progression have been documented in domestic cats. Gene therapy for canine retinopathies has been successful, thus the cat could be a gene therapy candidate for other forms of retinal degenerations. The current study investigates a hereditary, autosomal recessive, retinal degeneration specific to Persian cats. A multi-generational pedigree segregating for this progressive retinal atrophy was genotyped using a 63 K SNP array and analyzed via genome-wide linkage and association methods. A multi-point parametric linkage analysis localized the blindness phenotype to a ~1.75 Mb region with significant LOD scores (Z ≈ 14, θ = 0.00) on cat chromosome E1. Genome-wide TDT, sib-TDT, and case-control analyses also consistently supported significant association within the same region on chromosome E1, which is homologous to human chromosome 17. Using haplotype analysis, a ~1.3 Mb region was identified as highly associated for progressive retinal atrophy in Persian cats. Several candidate genes within the region are reasonable candidates as a potential causative gene and should be considered for molecular analyses.

  12. Genome-wide family-based linkage analysis of exome chip variants and cardiometabolic risk.

    PubMed

    Hellwege, Jacklyn N; Palmer, Nicholette D; Raffield, Laura M; Ng, Maggie C Y; Hawkins, Gregory A; Long, Jirong; Lorenzo, Carlos; Norris, Jill M; Ida Chen, Y-D; Speliotes, Elizabeth K; Rotter, Jerome I; Langefeld, Carl D; Wagenknecht, Lynne E; Bowden, Donald W

    2014-05-01

    Linkage analysis of complex traits has had limited success in identifying trait-influencing loci. Recently, coding variants have been implicated as the basis for some biomedical associations. We tested whether coding variants are the basis for linkage peaks of complex traits in 42 African-American (n = 596) and 90 Hispanic (n = 1,414) families in the Insulin Resistance Atherosclerosis Family Study (IRASFS) using Illumina HumanExome Beadchips. A total of 92,157 variants in African Americans (34%) and 81,559 (31%) in Hispanics were polymorphic and tested using two-point linkage and association analyses with 37 cardiometabolic phenotypes. In African Americans 77 LOD scores greater than 3 were observed. The highest LOD score was 4.91 with the APOE SNP rs7412 (MAF = 0.13) with plasma apolipoprotein B (ApoB). This SNP was associated with ApoB (P-value = 4 × 10(-19)) and accounted for 16.2% of the variance in African Americans. In Hispanic families, 104 LOD scores were greater than 3. The strongest evidence of linkage (LOD = 4.29) was with rs5882 (MAF = 0.46) in CETP with HDL. CETP variants were strongly associated with HDL (0.00049 < P-value <4.6 × 10(-12)), accounting for up to 4.5% of the variance. These loci have previously been shown to have effects on the biomedical traits evaluated here. Thus, evidence of strong linkage in this genome wide survey of primarily coding variants was uncommon. Loci with strong evidence of linkage was characterized by large contributions to the variance, and, in these cases, are common variants. Less compelling evidence of linkage and association was observed with additional loci that may require larger family sets to confirm. © 2014 WILEY PERIODICALS, INC.

  13. A genome-wide linkage study of mammographic density, a risk factor for breast cancer

    PubMed Central

    2011-01-01

    Introduction Mammographic breast density is a highly heritable (h2 > 0.6) and strong risk factor for breast cancer. We conducted a genome-wide linkage study to identify loci influencing mammographic breast density (MD). Methods Epidemiological data were assembled on 1,415 families from the Australia, Northern California and Ontario sites of the Breast Cancer Family Registry, and additional families recruited in Australia and Ontario. Families consisted of sister pairs with age-matched mammograms and data on factors known to influence MD. Single nucleotide polymorphism (SNP) genotyping was performed on 3,952 individuals using the Illumina Infinium 6K linkage panel. Results Using a variance components method, genome-wide linkage analysis was performed using quantitative traits obtained by adjusting MD measurements for known covariates. Our primary trait was formed by fitting a linear model to the square root of the percentage of the breast area that was dense (PMD), adjusting for age at mammogram, number of live births, menopausal status, weight, height, weight squared, and menopausal hormone therapy. The maximum logarithm of odds (LOD) score from the genome-wide scan was on chromosome 7p14.1-p13 (LOD = 2.69; 63.5 cM) for covariate-adjusted PMD, with a 1-LOD interval spanning 8.6 cM. A similar signal was seen for the covariate adjusted area of the breast that was dense (DA) phenotype. Simulations showed that the complete sample had adequate power to detect LOD scores of 3 or 3.5 for a locus accounting for 20% of phenotypic variance. A modest peak initially seen on chromosome 7q32.3-q34 increased in strength when only the 513 families with at least two sisters below 50 years of age were included in the analysis (LOD 3.2; 140.7 cM, 1-LOD interval spanning 9.6 cM). In a subgroup analysis, we also found a LOD score of 3.3 for DA phenotype on chromosome 12.11.22-q13.11 (60.8 cM, 1-LOD interval spanning 9.3 cM), overlapping a region identified in a previous study

  14. A genome-wide linkage study of mammographic density, a risk factor for breast cancer.

    PubMed

    Greenwood, Celia M T; Paterson, Andrew D; Linton, Linda; Andrulis, Irene L; Apicella, Carmel; Dimitromanolakis, Apostolos; Kriukov, Valentina; Martin, Lisa J; Salleh, Ayesha; Samiltchuk, Elena; Parekh, Rashmi V; Southey, Melissa C; John, Esther M; Hopper, John L; Boyd, Norman F; Rommens, Johanna M

    2011-01-01

    Mammographic breast density is a highly heritable (h2 > 0.6) and strong risk factor for breast cancer. We conducted a genome-wide linkage study to identify loci influencing mammographic breast density (MD). Epidemiological data were assembled on 1,415 families from the Australia, Northern California and Ontario sites of the Breast Cancer Family Registry, and additional families recruited in Australia and Ontario. Families consisted of sister pairs with age-matched mammograms and data on factors known to influence MD. Single nucleotide polymorphism (SNP) genotyping was performed on 3,952 individuals using the Illumina Infinium 6K linkage panel. Using a variance components method, genome-wide linkage analysis was performed using quantitative traits obtained by adjusting MD measurements for known covariates. Our primary trait was formed by fitting a linear model to the square root of the percentage of the breast area that was dense (PMD), adjusting for age at mammogram, number of live births, menopausal status, weight, height, weight squared, and menopausal hormone therapy. The maximum logarithm of odds (LOD) score from the genome-wide scan was on chromosome 7p14.1-p13 (LOD = 2.69; 63.5 cM) for covariate-adjusted PMD, with a 1-LOD interval spanning 8.6 cM. A similar signal was seen for the covariate adjusted area of the breast that was dense (DA) phenotype. Simulations showed that the complete sample had adequate power to detect LOD scores of 3 or 3.5 for a locus accounting for 20% of phenotypic variance. A modest peak initially seen on chromosome 7q32.3-q34 increased in strength when only the 513 families with at least two sisters below 50 years of age were included in the analysis (LOD 3.2; 140.7 cM, 1-LOD interval spanning 9.6 cM). In a subgroup analysis, we also found a LOD score of 3.3 for DA phenotype on chromosome 12.11.22-q13.11 (60.8 cM, 1-LOD interval spanning 9.3 cM), overlapping a region identified in a previous study. The suggestive peaks and the larger

  15. Genome-wide linkage analysis replicates susceptibility locus for fasting plasma triglycerides: NHLBI Family Heart Study.

    PubMed

    Arnett, Donna K; Miller, Michael B; Coon, Hilary; Ellison, R Curtis; North, Kari E; Province, Michael; Leppert, Mark; Eckfeldt, John H

    2004-11-01

    Recent reports implicate chromosomal regions linked to inter-individual variation in plasma triglycerides. We conducted genome-wide scans to replicate these linkages and/or identify other loci influencing plasma triglycerides in the NHLBI Family Heart Study (FHS). Data were obtained for 501 three-generational families. Genotyping was done by the Utah Molecular Genetics Laboratory and NHLBI Mammalian Genotyping Service; markers from both were placed on one genetic map. Analysis was done using multipoint variance components linkage. Fasting plasma triglycerides were log-transformed and age-, sex-, and field center-adjusted; suggestive linkage evidence was found on chromosome 8 (LOD=2.80 at 89 cM, marker D8S1141). Further adjustment for waist girth, BMI, diabetes, hypertension, and lipid-lowering drugs suggested linkage regions on chromosomes 6 (LOD=2.29 at 79 cM, marker D6S295) and 15 (LOD=1.85 at 43 cM, marker D15S659). Since HDL is correlated with triglycerides and because it was linked to this region on chromosome 15 in FHS, we created a composite triglyceride-HDL phenotype. The combined phenotype LOD score was 3.0 at the same marker on chromosome 15. Chromosome 15 likely harbors a susceptibility locus with an influence on triglycerides and HDL. Regions on chromosomes 6 and 8 may also contain loci contributing to inter-individual variation in plasma triglycerides.

  16. A genome-wide scan in affected sibling pairs with idiopathic recurrent miscarriage suggests genetic linkage.

    PubMed

    Kolte, A M; Nielsen, H S; Moltke, I; Degn, B; Pedersen, B; Sunde, L; Nielsen, F C; Christiansen, O B

    2011-06-01

    Previously, siblings of patients with idiopathic recurrent miscarriage (IRM) have been shown to have a higher risk of miscarriage. This study comprises two parts: (i) an epidemiological part, in which we introduce data on the frequency of miscarriage among 268 siblings of 244 patients with IRM and (ii) a genetic part presenting data from a genome-wide linkage study of 38 affected sibling pairs with IRM. All IRM patients (probands) had experienced three or more miscarriages and affected siblings two or more miscarriages. The sibling pairs were genotyped by the Affymetrix GeneChip 50K XbaI platform and non-parametric linkage analysis was performed via the software package Merlin. We find that siblings of IRM patients exhibit a higher frequency of miscarriage than population controls regardless of age at the time of pregnancy. We identify chromosomal regions with LOD scores between 2.5 and 3.0 in subgroups of affected sibling pairs. Maximum LOD scores were identified in four occurrences: for rs10514716 (3p14.2) when analyzing sister-pairs only; for rs10511668 (9p22.1) and rs341048 (11q13.4) when only analyzing families where the probands have had four or more miscarriages; and for rs10485275 (6q16.3) when analyzing one sibling pair from each family only. We identify no founder mutations. Concluding, our results imply that IRM patients and their siblings share factors which increase the risk of miscarriage. In this first genome-wide linkage study of affected sibling pairs with IRM, we identify regions on chromosomes 3, 6, 9 and 11 which warrant further investigation in order to elucidate their putative roles in the genesis of IRM.

  17. Genome-wide linkage analysis and association study identifies loci for polydactyly in chickens.

    PubMed

    Sun, Yanfa; Liu, Ranran; Zhao, Guiping; Zheng, Maiqing; Sun, Yan; Yu, Xiaoqiong; Li, Peng; Wen, Jie

    2014-04-21

    Polydactyly occurs in some chicken breeds, but the molecular mechanism remains incompletely understood. Combined genome-wide linkage analysis and association study (GWAS) for chicken polydactyly helps identify loci or candidate genes for the trait and potentially provides further mechanistic understanding of this phenotype in chickens and perhaps other species. The linkage analysis and GWAS for polydactyly was conducted using an F2 population derived from Beijing-You chickens and commercial broilers. The results identified two QTLs through linkage analysis and seven single-nucleotide polymorphisms (SNPs) through GWAS, associated with the polydactyly trait. One QTL located at 35 cM on the GGA2 was significant at the 1% genome-wise level and another QTL at the 1% chromosome-wide significance level was detected at 39 cM on GGA19. A total of seven SNPs, four of 5% genome-wide significance (P < 2.98 × 10(-6)) and three of suggestive significance (5.96 × 10(-5)) were identified, including two SNPs (GGaluGA132178 and Gga_rs14135036) in the QTL on GGA2. Of the identified SNPs, the eight nearest genes were sonic hedgehog (SHH), limb region 1 homolog (mouse) (LMBR1), dipeptidyl-peptidase 6, transcript variant 3 (DPP6), thyroid-stimulating hormone, beta (TSHB), sal-like 4 (Drosophila) (SALL4), par-6 partitioning defective 6 homolog beta (Caenorhabditis elegans) (PARD6B), coenzyme Q5 (COQ5), and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, etapolypeptide (YWHAH). The GWAS supports earlier reports of the importance of SHH and LMBR1 as regulating genes for polydactyly in chickens and other species, and identified others, most of which have not previously been associated with limb development. The genes and associated SNPs revealed here provide detailed information for further exploring the molecular and developmental mechanisms underlying polydactyly.

  18. Genome-Wide Linkage Analysis Identifies Loci for Physical Appearance Traits in Chickens.

    PubMed

    Sun, Yanfa; Liu, Ranran; Zhao, Guiping; Zheng, Maiqing; Sun, Yan; Yu, Xiaoqiong; Li, Peng; Wen, Jie

    2015-08-06

    Physical appearance traits, such as feather-crested head, comb size and type, beard, wattles size, and feathered feet, are used to distinguish between breeds of chicken and also may be associated with economic traits. In this study, a genome-wide linkage analysis was used to identify candidate regions and genes for physical appearance traits and to potentially provide further knowledge of the molecular mechanisms that underlie these traits. The linkage analysis was conducted with an F2 population derived from Beijing-You chickens and a commercial broiler line. Single-nucleotide polymorphisms were analyzed using the Illumina 60K Chicken SNP Beadchip. The data were used to map quantitative trait loci and genes for six physical appearance traits. A 10-cM/0.51-Mb region (0.0-10.0 cM/0.00-0.51 Mb) with 1% genome-wide significant level on LGE22C19W28_E50C23 linkage group (LGE22) for crest trait was identified, which is likely very closely linked to the HOXC8. A QTL with 5% chromosome-wide significant level for comb weight, which partly overlaps with a region identified in a previous study, was identified at 74 cM/25.55 Mb on chicken (Gallus gallus; GG) chromosome 3 (i.e., GGA3). For beard and wattles traits, an identical region 11 cM/2.23 Mb (0.0-11.0 cM/0.00-2.23 Mb) including WNT3 and GH genes on GGA27 was identified. Two QTL with 1% genome-wide significant level for feathered feet trait, one 9-cM/2.80-Mb (48.0-57.0/13.40-16.20 Mb) region on GGA13, and another 12-cM/1.45-Mb (41.0-53.0 cM/11.37-12.82 Mb) region on GGA15 were identified. These candidate regions and genes provide important genetic information for the physical appearance traits in chicken. Copyright © 2015 Sun et al.

  19. Genome-Wide Linkage Analysis Identifies Loci for Physical Appearance Traits in Chickens

    PubMed Central

    Sun, Yanfa; Liu, Ranran; Zhao, Guiping; Zheng, Maiqing; Sun, Yan; Yu, Xiaoqiong; Li, Peng; Wen, Jie

    2015-01-01

    Physical appearance traits, such as feather-crested head, comb size and type, beard, wattles size, and feathered feet, are used to distinguish between breeds of chicken and also may be associated with economic traits. In this study, a genome-wide linkage analysis was used to identify candidate regions and genes for physical appearance traits and to potentially provide further knowledge of the molecular mechanisms that underlie these traits. The linkage analysis was conducted with an F2 population derived from Beijing-You chickens and a commercial broiler line. Single-nucleotide polymorphisms were analyzed using the Illumina 60K Chicken SNP Beadchip. The data were used to map quantitative trait loci and genes for six physical appearance traits. A 10-cM/0.51-Mb region (0.0−10.0 cM/0.00−0.51 Mb) with 1% genome-wide significant level on LGE22C19W28_E50C23 linkage group (LGE22) for crest trait was identified, which is likely very closely linked to the HOXC8. A QTL with 5% chromosome-wide significant level for comb weight, which partly overlaps with a region identified in a previous study, was identified at 74 cM/25.55 Mb on chicken (Gallus gallus; GG) chromosome 3 (i.e., GGA3). For beard and wattles traits, an identical region 11 cM/2.23 Mb (0.0−11.0 cM/0.00−2.23 Mb) including WNT3 and GH genes on GGA27 was identified. Two QTL with 1% genome-wide significant level for feathered feet trait, one 9-cM/2.80-Mb (48.0-57.0/13.40-16.20 Mb) region on GGA13, and another 12-cM/1.45-Mb (41.0−53.0 cM/11.37−12.82 Mb) region on GGA15 were identified. These candidate regions and genes provide important genetic information for the physical appearance traits in chicken. PMID:26248982

  20. Genome-wide analysis of zygotic linkage disequilibrium and its components in crossbred cattle

    PubMed Central

    2012-01-01

    Background Linkage disequilibrium (LD) between genes at linked or independent loci can occur at gametic and zygotic levels known asgametic LD and zygotic LD, respectively. Gametic LD is well known for its roles in fine-scale mapping of quantitative trait loci, genomic selection and evolutionary inference. The less-well studied is the zygotic LD and its components that can be also estimated directly from the unphased SNPs. Results This study was set up to investigate the genome-wide extent and patterns of zygotic LD and its components in a crossbred cattle population using the genomic data from the Illumina BovineSNP50 beadchip. The animal population arose from repeated crossbreeding of multiple breeds and selection for growth and cow reproduction. The study showed that similar genomic structures in gametic and zygotic LD were observed, with zygotic LD decaying faster than gametic LD over marker distance. The trigenic and quadrigenic disequilibria were generally two- to three-fold smaller than the usual digenic disequilibria (gametic or composite LD). There was less power of testing for these high-order genic disequilibria than for the digenic disequilibria. The power estimates decreased with the marker distance between markers though the decay trend is more obvious for the digenic disequilibria than for high-order disequilibria. Conclusions This study is the first major genome-wide survey of all non-allelic associations between pairs of SNPs in a cattle population. Such analysis allows us to assess the relative importance of gametic LD vs. all other non-allelic genic LDs regardless of whether or not the population is in HWE. The observed predominance of digenic LD (gametic or composite LD) coupled with insignificant high-order trigenic and quadrigenic disequilibria supports the current intensive focus on the use of high-density SNP markers for genome-wide association studies and genomic selection activities in the cattle population. PMID:22827586

  1. Refining genome-wide linkage intervals using a meta-analysis of genome-wide association studies identifies loci influencing personality dimensions

    PubMed Central

    Amin, Najaf; Hottenga, Jouke-Jan; Hansell, Narelle K; Janssens, A Cecile JW; de Moor, Marleen HM; Madden, Pamela AF; Zorkoltseva, Irina V; Penninx, Brenda W; Terracciano, Antonio; Uda, Manuela; Tanaka, Toshiko; Esko, Tonu; Realo, Anu; Ferrucci, Luigi; Luciano, Michelle; Davies, Gail; Metspalu, Andres; Abecasis, Goncalo R; Deary, Ian J; Raikkonen, Katri; Bierut, Laura J; Costa, Paul T; Saviouk, Viatcheslav; Zhu, Gu; Kirichenko, Anatoly V; Isaacs, Aaron; Aulchenko, Yurii S; Willemsen, Gonneke; Heath, Andrew C; Pergadia, Michele L; Medland, Sarah E; Axenovich, Tatiana I; de Geus, Eco; Montgomery, Grant W; Wright, Margaret J; Oostra, Ben A; Martin, Nicholas G; Boomsma, Dorret I; van Duijn, Cornelia M

    2013-01-01

    Personality traits are complex phenotypes related to psychosomatic health. Individually, various gene finding methods have not achieved much success in finding genetic variants associated with personality traits. We performed a meta-analysis of four genome-wide linkage scans (N=6149 subjects) of five basic personality traits assessed with the NEO Five-Factor Inventory. We compared the significant regions from the meta-analysis of linkage scans with the results of a meta-analysis of genome-wide association studies (GWAS) (N∼17 000). We found significant evidence of linkage of neuroticism to chromosome 3p14 (rs1490265, LOD=4.67) and to chromosome 19q13 (rs628604, LOD=3.55); of extraversion to 14q32 (ATGG002, LOD=3.3); and of agreeableness to 3p25 (rs709160, LOD=3.67) and to two adjacent regions on chromosome 15, including 15q13 (rs970408, LOD=4.07) and 15q14 (rs1055356, LOD=3.52) in the individual scans. In the meta-analysis, we found strong evidence of linkage of extraversion to 4q34, 9q34, 10q24 and 11q22, openness to 2p25, 3q26, 9p21, 11q24, 15q26 and 19q13 and agreeableness to 4q34 and 19p13. Significant evidence of association in the GWAS was detected between openness and rs677035 at 11q24 (P-value=2.6 × 10−06, KCNJ1). The findings of our linkage meta-analysis and those of the GWAS suggest that 11q24 is a susceptible locus for openness, with KCNJ1 as the possible candidate gene. PMID:23211697

  2. Refining genome-wide linkage intervals using a meta-analysis of genome-wide association studies identifies loci influencing personality dimensions.

    PubMed

    Amin, Najaf; Hottenga, Jouke-Jan; Hansell, Narelle K; Janssens, A Cecile J W; de Moor, Marleen H M; Madden, Pamela A F; Zorkoltseva, Irina V; Penninx, Brenda W; Terracciano, Antonio; Uda, Manuela; Tanaka, Toshiko; Esko, Tonu; Realo, Anu; Ferrucci, Luigi; Luciano, Michelle; Davies, Gail; Metspalu, Andres; Abecasis, Goncalo R; Deary, Ian J; Raikkonen, Katri; Bierut, Laura J; Costa, Paul T; Saviouk, Viatcheslav; Zhu, Gu; Kirichenko, Anatoly V; Isaacs, Aaron; Aulchenko, Yurii S; Willemsen, Gonneke; Heath, Andrew C; Pergadia, Michele L; Medland, Sarah E; Axenovich, Tatiana I; de Geus, Eco; Montgomery, Grant W; Wright, Margaret J; Oostra, Ben A; Martin, Nicholas G; Boomsma, Dorret I; van Duijn, Cornelia M

    2013-08-01

    Personality traits are complex phenotypes related to psychosomatic health. Individually, various gene finding methods have not achieved much success in finding genetic variants associated with personality traits. We performed a meta-analysis of four genome-wide linkage scans (N=6149 subjects) of five basic personality traits assessed with the NEO Five-Factor Inventory. We compared the significant regions from the meta-analysis of linkage scans with the results of a meta-analysis of genome-wide association studies (GWAS) (N∼17 000). We found significant evidence of linkage of neuroticism to chromosome 3p14 (rs1490265, LOD=4.67) and to chromosome 19q13 (rs628604, LOD=3.55); of extraversion to 14q32 (ATGG002, LOD=3.3); and of agreeableness to 3p25 (rs709160, LOD=3.67) and to two adjacent regions on chromosome 15, including 15q13 (rs970408, LOD=4.07) and 15q14 (rs1055356, LOD=3.52) in the individual scans. In the meta-analysis, we found strong evidence of linkage of extraversion to 4q34, 9q34, 10q24 and 11q22, openness to 2p25, 3q26, 9p21, 11q24, 15q26 and 19q13 and agreeableness to 4q34 and 19p13. Significant evidence of association in the GWAS was detected between openness and rs677035 at 11q24 (P-value=2.6 × 10(-06), KCNJ1). The findings of our linkage meta-analysis and those of the GWAS suggest that 11q24 is a susceptible locus for openness, with KCNJ1 as the possible candidate gene.

  3. Genome-wide linkage analysis of pulse pressure in American Indians: the Strong Heart Study.

    PubMed

    Franceschini, Nora; MacCluer, Jean W; Rose, Kathreen M; Rutherford, Sue; Cole, Shelley A; Laston, Sandy; Göring, Harald H H; Diego, Vincent P; Roman, Mary J; Lee, Elisa T; Best, Lyle G; Howard, Barbara V; Fabsitz, Richard R; North, Kari E

    2008-02-01

    Pulse pressure, a measure of central arterial stiffness and a predictor of cardiovascular mortality, has known genetic components. To localize the genetic effects of pulse pressure, we conducted a genome-wide linkage analysis of 1,892 American-Indian participants of the Strong Heart Family Study (SHFS). Blood pressure was measured three times and the average of the last two measures was used for analyses. Pulse pressure, the difference between systolic blood pressure (SBP) and diastolic blood pressure (DBP), was log-transformed and adjusted for the effects of age and sex within each study center. Variance component linkage analyses were performed using marker allele frequencies derived from all individuals and multipoint identity-by-descent matrices calculated in Loki. We identified a quantitative-trait locus influencing pulse pressure on chromosome 7 at 37 cM (marker D7S493, LOD = 3.3) and suggestive evidence of linkage on chromosome 19 at 92 cM (marker D19S888, LOD = 1.8). The signal on 7p15.3 overlaps positive findings for pulse pressure among Utah population samples, suggesting that this region may harbor gene variants for blood pressure related traits.

  4. GENOME-WIDE LINKAGE ANALYSIS OF PULSE PRESSURE IN AMERICAN INDIANS: THE STRONG HEART STUDY

    PubMed Central

    Franceschini, Nora; MacCluer, Jean W.; Rose, Kathreen M.; Rutherford, Sue; Cole, Shelley A.; Laston, Sandy; Göring, Harald H.H.; Diego, Vincent P.; Roman, Mary J.; Lee, Elisa T.; Best, Lyle G.; Howard, Barbara V.; Fabsitz, Richard R.; North, Kari E.

    2010-01-01

    Background Pulse pressure, a measure of central arterial stiffness and a predictor of cardiovascular mortality, has known genetic components. Methods To localize the genetic effects of pulse pressure, we conducted a genome-wide linkage analysis of 1,892 American Indian participants of the Strong Heart Family Study. Blood pressure was measured three times and the average of the last two measures was used for analyses. Pulse pressure, the difference between systolic and diastolic blood pressures, was log-transformed and adjusted for the effects of age and sex within each study center. Variance component linkage analyses were performed using marker allele frequencies derived from all individuals and multipoint identity-by-descent matrices calculated in Loki. Results We identified a quantitative trait locus influencing pulse pressure on chromosome 7 at 37 cM (marker D7S493, LOD=3.3) and suggestive evidence of linkage on chromosome 19 at 92 cM (marker D19S888, LOD=1.8). Conclusions The signal on 7p15.3 overlaps positive findings for pulse pressure among Utah population samples, suggesting that this region may harbor gene variants for blood pressure related traits. PMID:18188160

  5. Genome-wide Linkage on Chromosome 10q26 for a Dimensional Scale of Major Depression

    PubMed Central

    Knowles, Emma. E. M.; Kent, Jack W.; McKay, D. Reese; Sprooten, Emma; Mathias, Samuel R.; Curran, Joanne E.; Carless, Melanie A.; de Almeida, Marcio A. A.; Goring, Harald, H. H.; Dyer, Tom D.; Olvera, Rene L.; Fox, Peter T.; Duggirala, Ravi; Almasy, Laura; Blangero, John; Glahn, David C.

    2015-01-01

    Major depressive disorder (MDD) is a common and potentially life-threatening mood disorder. Identifying genetic markers for depression might provide reliable indicators of depression risk, which would, in turn, substantially improve detection, enabling earlier and more effective treatment. The aim of this study was to identify rare variants for depression, modeled as a continuous trait, using linkage and post-hoc association analysis. The sample comprised 1221 Mexican-American individuals from extended pedigrees. A single dimensional scale of MDD was derived using confirmatory factor analysis applied to all items from the Past Major Depressive Episode section of the Mini-International Neuropsychiatric Interview. Scores on this scale of depression were subjected to linkage analysis followed by QTL region-specific association analysis. Linkage analysis revealed a single genome-wide significant QTL (LOD = 3.43) on 10q26.13, QTL-specific association analysis conducted in the entire sample revealed a suggestive variant within an intron of the gene LHPP (rs11245316, p = 7.8×10-04; LD-adjusted Bonferroni-corrected p = 8.6×10-05). This region of the genome has previously been implicated in the etiology of MDD; the present study extends our understanding of the involvement of this region by highlighting a putative gene of interest (LHPP). PMID:26655122

  6. Genome-wide linkage scan for the metabolic syndrome: the GENNID study.

    PubMed

    Edwards, Karen L; Hutter, Carolyn M; Wan, Jia Yin; Kim, Helen; Monks, Stephanie A

    2008-07-01

    In the United States, the metabolic syndrome (MetS) constitutes a major public health problem with over 47 million persons meeting clinical criteria for MetS. Numerous studies have suggested genetic susceptibility to MetS. The goals of this study were (i) to identify susceptibility loci for MetS in well-characterized families with type 2 diabetes (T2D) in four ethnic groups and (ii) to determine whether evidence for linkage varies across the four groups. The GENNID study (Genetics of NIDDM) is a multicenter study established by the American Diabetes Association in 1993 and comprises a comprehensive, well-characterized resource of T2D families from four ethnic groups (whites, Mexican Americans, African Americans, and Japanese Americans). Principal component factor analysis (PCFA) was used to define quantitative phenotypes of the MetS. Variance components linkage analysis was conducted using microsatellite markers from a 10-cM genome-wide linkage scan, separately in each of the four ethnic groups. Three quantitative MetS factors were identified by PCFA and used as phenotypes for MetS: (i) a weight/waist factor, (ii) a blood pressure factor, and (iii) a lipid factor. Evidence for linkage to each of these factors was observed. For each ethnic group, our results suggest that several regions harbor susceptibility genes for the MetS. The strongest evidence for linkage for MetS phenotypes was observed on chromosome 2 (2q12.1-2q13) in the white sample and on chromosome 3 (3q26.1-3q29) in the Mexican-American sample. In conclusion, the results suggest that several regions harbor MetS susceptibility genes and that heterogeneity may exist across groups.

  7. Genome-wide linkage scan for submaximal exercise heart rate in the HERITAGE family study.

    PubMed

    Spielmann, Nadine; Leon, Arthur S; Rao, D C; Rice, Treva; Skinner, James S; Rankinen, Tuomo; Bouchard, Claude

    2007-12-01

    The purpose of this study was to identify regions of the human genome linked to submaximal exercise heart rates in the sedentary state and in response to a standardized 20-wk endurance training program in blacks and whites of the HERITAGE Family Study. A total of 701 polymorphic markers covering the 22 autosomes were used in the genome-wide linkage scan, with 328 sibling pairs from 99 white nuclear families and 102 pairs from 115 black family units. Steady-state heart rates were measured at the relative intensity of 60% maximal oxygen uptake (HR60) and at the absolute intensity of 50 W (HR50). Baseline phenotypes were adjusted for age, sex, and baseline body mass index (BMI) and training responses (posttraining minus baseline, Delta) were adjusted for age, sex, baseline BMI, and baseline value of the phenotype. Two analytic strategies were used, a multipoint variance components and a regression-based multipoint linkage analysis. In whites, promising linkages (LOD > 1.75) were identified on 18q21-q22 for baseline HR50 (LOD = 2.64; P = 0.0002) and DeltaHR60 (LOD = 2.10; P = 0.0009) and on chromosome 2q33.3 for DeltaHR50 (LOD = 2.13; P = 0.0009). In blacks, evidence of promising linkage for baseline HR50 was detected with several markers within the chromosomal region 10q24-q25.3 (peak LOD = 2.43, P = 0.0004 with D10S597). The most promising regions for fine mapping in the HERITAGE Family Study were found on 2q33 for HR50 training response in whites, on 10q25-26 for baseline HR60 in blacks, and on 18q21-22 for both baseline HR50 and DeltaHR60 in whites.

  8. Accounting for linkage disequilibrium in genome-wide association studies: A penalized regression method.

    PubMed

    Liu, Jin; Wang, Kai; Ma, Shuangge; Huang, Jian

    2013-01-01

    Penalized regression methods are becoming increasingly popular in genome-wide association studies (GWAS) for identifying genetic markers associated with disease. However, standard penalized methods such as LASSO do not take into account the possible linkage disequilibrium between adjacent markers. We propose a novel penalized approach for GWAS using a dense set of single nucleotide polymorphisms (SNPs). The proposed method uses the minimax concave penalty (MCP) for marker selection and incorporates linkage disequilibrium (LD) information by penalizing the difference of the genetic effects at adjacent SNPs with high correlation. A coordinate descent algorithm is derived to implement the proposed method. This algorithm is efficient in dealing with a large number of SNPs. A multi-split method is used to calculate the p-values of the selected SNPs for assessing their significance. We refer to the proposed penalty function as the smoothed MCP and the proposed approach as the SMCP method. Performance of the proposed SMCP method and its comparison with LASSO and MCP approaches are evaluated through simulation studies, which demonstrate that the proposed method is more accurate in selecting associated SNPs. Its applicability to real data is illustrated using heterogeneous stock mice data and a rheumatoid arthritis.

  9. Genome-wide searches for bipolar disorder genes.

    PubMed

    Alsabban, Shaza; Rivera, Margarita; McGuffin, Peter

    2011-12-01

    Whole-genome linkage and association studies of bipolar disorder are beginning to provide some compelling evidence for the involvement of several chromosomal regions and susceptibility genes in the pathogenesis of bipolar disorder. Developments in genotyping technology and efforts to combine data from different studies have helped in identifying chromosomes 6q16-q25, 13q, and 16p12 as probable susceptibility loci for bipolar disorder and confirmed CACNA1C and ANK3 as susceptibility genes for bipolar disorder. However, a lack of replication is still apparent in the literature. New studies focusing on copy number variants as well as new analytical approaches utilizing pathway analysis offer a new direction in the study of the genetics of bipolar disorder.

  10. Genome-wide linkage analysis for uric acid in families enriched for hypertension

    PubMed Central

    Rule, Andrew D.; Fridley, Brooke L.; Hunt, Steven C.; Asmann, Yan; Boerwinkle, Eric; Pankow, James S.; Mosley, Thomas H.; Turner, Stephen T.

    2009-01-01

    Background. Uric acid is heritable and associated with hypertension and insulin resistance. We sought to identify genomic regions influencing serum uric acid in families in which two or more siblings had hypertension. Methods. Uric acid levels and microsatellite markers were assayed in the Genetic Epidemiology Network of Arteriopathy (GENOA) cohort (1075 whites and 1333 blacks) and the Hypertension Genetic Epidemiology Network (HyperGEN) cohort (1542 whites and 1627 blacks). Genome-wide linkage analyses of uric acid and bivariate linkage analyses of uric acid with an additional surrogate of insulin resistance were completed. Pathway analysis explored gene sets enriched at loci influencing uric acid. Results. In the GENOA white cohort, loci influencing uric acid were identified on chromosome 8 at 135 cM [multipoint logarithm of odds score (MLS) = 2.4], on chromosome 9 at 113 cM (MLS = 3.7) and on chromosome 16 at 93 cM (MLS = 2.3), but did not replicate in HyperGEN. At these loci, there was evidence of pleiotropy with other surrogates of insulin resistance and genes in the fructose and mannose metabolism pathway were enriched. In the HyperGEN-black cohort, there was some evidence of a locus for uric acid on chromosome 4 at 135 cM (MLS = 2.4) that had modest replication in GENOA (MLS = 1.2). Conclusions. Several novel loci linked to uric acid were identified but none showed clear replication. Widespread diuretic use, a medication that raises uric acid levels, was an important study limitation. Bivariate linkage analyses and pathway analysis were consistent with genes regulating insulin resistance and fructose metabolism contributing to the heritability of uric acid. PMID:19258383

  11. Genome-wide linkage analysis and physical mapping of the rippling muscle disease gene

    SciTech Connect

    Stephan, D.A.; Buist, N.R.M.; Bhaskar, A.C.

    1994-09-01

    Rippling muscle disease (RMD) is an inherited disorder of skeletal muscle in which mechanical stimuli provoke electrically silent contractions. The patient`s symptoms are muscle cramps, pain, and stiffness, particularly during or following exercise. Clinical signs are balling of muscle following percussion, and a characteristic lateral rolling movement of muscle occurring after contraction followed by stretching. We report a new 44-member pedigree segregating RMD as an autosomal dominant trait. A genome-wide genetic linkage study in this family, using a novel approach of testing closely spaced highly polymorphic markers in affected individuals, localized the responsible gene to the distal end of the long arm of chromosome 1 with a maximum multi-point lod score of 3.56 ({theta}=0). In this family, RMD is localized to a 6 cM region near D1S235. Physical mapping of the linked region yielded several positive YAC clones, one of which spans the entire 6 cM distance. Several candidate genes not present in the YAC contig, but in the region of 1q4, have been excluded as causative by either linkage analysis of intragenic microsatellite repeats (alpha-actinin, angiotensinogen) or by SSCP of exons (skeletal muscle alpha-actinin). We studied two previously reported German families for linkage to the same locus and this same area did not co-segregate with the disease, a finding that shows that different genetic defects can cause a similar clinical phenotype (genetic heterogeneity). An understanding of the defect in contraction control within the muscle fibers in this disease may lead to a better understanding of muscle force transduction, intracellular calcium homeostasis, or both.

  12. Genome-wide linkage using the Social Responsiveness Scale in Utah autism pedigrees

    PubMed Central

    2010-01-01

    Background Autism Spectrum Disorders (ASD) are phenotypically heterogeneous, characterized by impairments in the development of communication and social behaviour and the presence of repetitive behaviour and restricted interests. Dissecting the genetic complexity of ASD may require phenotypic data reflecting more detail than is offered by a categorical clinical diagnosis. Such data are available from the Social Responsiveness Scale (SRS) which is a continuous, quantitative measure of social ability giving scores that range from significant impairment to above average ability. Methods We present genome-wide results for 64 multiplex and extended families ranging from two to nine generations. SRS scores were available from 518 genotyped pedigree subjects, including affected and unaffected relatives. Genotypes from the Illumina 6 k single nucleotide polymorphism panel were provided by the Center for Inherited Disease Research. Quantitative and qualitative analyses were done using MCLINK, a software package that uses Markov chain Monte Carlo (MCMC) methods to perform multilocus linkage analysis on large extended pedigrees. Results When analysed as a qualitative trait, linkage occurred in the same locations as in our previous affected-only genome scan of these families, with findings on chromosomes 7q31.1-q32.3 [heterogeneity logarithm of the odds (HLOD) = 2.91], 15q13.3 (HLOD = 3.64), and 13q12.3 (HLOD = 2.23). Additional positive qualitative results were seen on chromosomes 6 and 10 in regions that may be of interest for other neuropsychiatric disorders. When analysed as a quantitative trait, results replicated a peak found in an independent sample using quantitative SRS scores on chromosome 11p15.1-p15.4 (HLOD = 2.77). Additional positive quantitative results were seen on chromosomes 7, 9, and 19. Conclusions The SRS linkage peaks reported here substantially overlap with peaks found in our previous affected-only genome scan of clinical diagnosis. In addition, we

  13. A genome-wide search for type 2 diabetes susceptibility genes in Utah Caucasians.

    PubMed

    Elbein, S C; Hoffman, M D; Teng, K; Leppert, M F; Hasstedt, S J

    1999-05-01

    Considerable evidence supports a major inherited component of type 2 diabetes. We initially conducted a genome-wide scan with 440 microsatellite markers at 10-cM intervals in 19 multigenerational families of Northern European ancestry with at least two diabetic siblings. Initial two-point analyses of these families directed marker typing of 23 additional families. Subsequently, all available marker data on the total of 42 families were analyzed using both parametric and nonparametric multipoint methods to test for linkage to type 2 diabetes. One locus on chromosome 1q21-1q23 met genome-wide criteria for significant linkage under a model of recessive inheritance with a common diabetes allele (logarithm of odds [LOD] = 4.295). Both pedigree-based nonparametric linkage (NPL) analysis and affected sib pair (MAPMAKER/SIBS) nonparametric methods also showed the highest genome-wide scores at this region, near markers CRP and APOA2, but failed to meet levels of genome-wide significance. The risk of type 2 diabetes to siblings of a diabetic person when compared with the population (lambdaS) was estimated from MAPMAKER/SIBS to be 2.8 in these 42 families. Simulation studies using study data confirmed a genome-wide significance level of P<0.05 (95% CI 0.005-0.0466). However, analysis of 20 similarly ascertained but smaller families failed to confirm this linkage. The LOD score with 50% heterogeneity for all 62 families considered together was only 2.25, with an estimated lambdaS of 1.87. Our data suggest a novel diabetes susceptibility locus near APOA2 on chromosome 1 in a region with many transcribed genes.

  14. Genome wide linkage disequilibrium in Chinese asparagus bean (Vigna. unguiculata ssp. sesquipedialis) germplasm: implications for domestication history and genome wide association studies

    PubMed Central

    Xu, P; Wu, X; Wang, B; Luo, J; Liu, Y; Ehlers, J D; Close, T J; Roberts, P A; Lu, Z; Wang, S; Li, G

    2012-01-01

    Association mapping of important traits of crop plants relies on first understanding the extent and patterns of linkage disequilibrium (LD) in the particular germplasm being investigated. We characterize here the genetic diversity, population structure and genome wide LD patterns in a set of asparagus bean (Vigna. unguiculata ssp. sesquipedialis) germplasm from China. A diverse collection of 99 asparagus bean and normal cowpea accessions were genotyped with 1127 expressed sequence tag-derived single nucleotide polymorphism markers (SNPs). The proportion of polymorphic SNPs across the collection was relatively low (39%), with an average number of SNPs per locus of 1.33. Bayesian population structure analysis indicated two subdivisions within the collection sampled that generally represented the ‘standard vegetable' type (subgroup SV) and the ‘non-standard vegetable' type (subgroup NSV), respectively. Level of LD (r2) was higher and extent of LD persisted longer in subgroup SV than in subgroup NSV, whereas LD decayed rapidly (0–2 cM) in both subgroups. LD decay distance varied among chromosomes, with the longest (≈5 cM) five times longer than the shortest (≈1 cM). Partitioning of LD variance into within- and between-subgroup components coupled with comparative LD decay analysis suggested that linkage group 5, 7 and 10 may have undergone the most intensive epistatic selection toward traits favorable for vegetable use. This work provides a first population genetic insight into domestication history of asparagus bean and demonstrates the feasibility of mapping complex traits by genome wide association study in asparagus bean using a currently available cowpea SNPs marker platform. PMID:22378357

  15. Genome wide linkage disequilibrium in Chinese asparagus bean (Vigna. unguiculata ssp. sesquipedialis) germplasm: implications for domestication history and genome wide association studies.

    PubMed

    Xu, P; Wu, X; Wang, B; Luo, J; Liu, Y; Ehlers, J D; Close, T J; Roberts, P A; Lu, Z; Wang, S; Li, G

    2012-07-01

    Association mapping of important traits of crop plants relies on first understanding the extent and patterns of linkage disequilibrium (LD) in the particular germplasm being investigated. We characterize here the genetic diversity, population structure and genome wide LD patterns in a set of asparagus bean (Vigna. unguiculata ssp. sesquipedialis) germplasm from China. A diverse collection of 99 asparagus bean and normal cowpea accessions were genotyped with 1127 expressed sequence tag-derived single nucleotide polymorphism markers (SNPs). The proportion of polymorphic SNPs across the collection was relatively low (39%), with an average number of SNPs per locus of 1.33. Bayesian population structure analysis indicated two subdivisions within the collection sampled that generally represented the 'standard vegetable' type (subgroup SV) and the 'non-standard vegetable' type (subgroup NSV), respectively. Level of LD (r(2)) was higher and extent of LD persisted longer in subgroup SV than in subgroup NSV, whereas LD decayed rapidly (0-2 cM) in both subgroups. LD decay distance varied among chromosomes, with the longest (≈ 5 cM) five times longer than the shortest (≈ 1 cM). Partitioning of LD variance into within- and between-subgroup components coupled with comparative LD decay analysis suggested that linkage group 5, 7 and 10 may have undergone the most intensive epistatic selection toward traits favorable for vegetable use. This work provides a first population genetic insight into domestication history of asparagus bean and demonstrates the feasibility of mapping complex traits by genome wide association study in asparagus bean using a currently available cowpea SNPs marker platform.

  16. Genome-wide linkage disequilibruim revealed by microsatellite markers and association study of fiber quality traits in cotton

    USDA-ARS?s Scientific Manuscript database

    The application of association mapping based on existing genome-wide linkage disequilibrium (LD) between DNA polymorphisms and genes underlying traits is becoming powerful tool that overcome many limitations (high cost, poor resolution, requirement for bi-parentally crossed lines assessing only two ...

  17. Population structure and linkage disequilibrium in oat (Avena sativa L.): implications for genome-wide association studies

    USDA-ARS?s Scientific Manuscript database

    The level of population structure and the extent of linkage disequilibrium (LD) can have large impacts on the power, resolution, and design of genome-wide association studies (GWAS) in plants. Until recently, the topics of LD and population structure have not been explored in oat due to the lack of...

  18. Creative Activities in Music--A Genome-Wide Linkage Analysis.

    PubMed

    Oikkonen, Jaana; Kuusi, Tuire; Peltonen, Petri; Raijas, Pirre; Ukkola-Vuoti, Liisa; Karma, Kai; Onkamo, Päivi; Järvelä, Irma

    2016-01-01

    Creative activities in music represent a complex cognitive function of the human brain, whose biological basis is largely unknown. In order to elucidate the biological background of creative activities in music we performed genome-wide linkage and linkage disequilibrium (LD) scans in musically experienced individuals characterised for self-reported composing, arranging and non-music related creativity. The participants consisted of 474 individuals from 79 families, and 103 sporadic individuals. We found promising evidence for linkage at 16p12.1-q12.1 for arranging (LOD 2.75, 120 cases), 4q22.1 for composing (LOD 2.15, 103 cases) and Xp11.23 for non-music related creativity (LOD 2.50, 259 cases). Surprisingly, statistically significant evidence for linkage was found for the opposite phenotype of creative activity in music (neither composing nor arranging; NCNA) at 18q21 (LOD 3.09, 149 cases), which contains cadherin genes like CDH7 and CDH19. The locus at 4q22.1 overlaps the previously identified region of musical aptitude, music perception and performance giving further support for this region as a candidate region for broad range of music-related traits. The other regions at 18q21 and 16p12.1-q12.1 are also adjacent to the previously identified loci with musical aptitude. Pathway analysis of the genes suggestively associated with composing suggested an overrepresentation of the cerebellar long-term depression pathway (LTD), which is a cellular model for synaptic plasticity. The LTD also includes cadherins and AMPA receptors, whose component GSG1L was linked to arranging. These results suggest that molecular pathways linked to memory and learning via LTD affect music-related creative behaviour. Musical creativity is a complex phenotype where a common background with musicality and intelligence has been proposed. Here, we implicate genetic regions affecting music-related creative behaviour, which also include genes with neuropsychiatric associations. We also propose

  19. Creative Activities in Music – A Genome-Wide Linkage Analysis

    PubMed Central

    Oikkonen, Jaana; Kuusi, Tuire; Peltonen, Petri; Raijas, Pirre; Ukkola-Vuoti, Liisa; Karma, Kai; Onkamo, Päivi; Järvelä, Irma

    2016-01-01

    Creative activities in music represent a complex cognitive function of the human brain, whose biological basis is largely unknown. In order to elucidate the biological background of creative activities in music we performed genome-wide linkage and linkage disequilibrium (LD) scans in musically experienced individuals characterised for self-reported composing, arranging and non-music related creativity. The participants consisted of 474 individuals from 79 families, and 103 sporadic individuals. We found promising evidence for linkage at 16p12.1-q12.1 for arranging (LOD 2.75, 120 cases), 4q22.1 for composing (LOD 2.15, 103 cases) and Xp11.23 for non-music related creativity (LOD 2.50, 259 cases). Surprisingly, statistically significant evidence for linkage was found for the opposite phenotype of creative activity in music (neither composing nor arranging; NCNA) at 18q21 (LOD 3.09, 149 cases), which contains cadherin genes like CDH7 and CDH19. The locus at 4q22.1 overlaps the previously identified region of musical aptitude, music perception and performance giving further support for this region as a candidate region for broad range of music-related traits. The other regions at 18q21 and 16p12.1-q12.1 are also adjacent to the previously identified loci with musical aptitude. Pathway analysis of the genes suggestively associated with composing suggested an overrepresentation of the cerebellar long-term depression pathway (LTD), which is a cellular model for synaptic plasticity. The LTD also includes cadherins and AMPA receptors, whose component GSG1L was linked to arranging. These results suggest that molecular pathways linked to memory and learning via LTD affect music-related creative behaviour. Musical creativity is a complex phenotype where a common background with musicality and intelligence has been proposed. Here, we implicate genetic regions affecting music-related creative behaviour, which also include genes with neuropsychiatric associations. We also propose

  20. Distribution of genome-wide linkage disequilibrium based on microsatellite loci in the Samoan population

    PubMed Central

    2004-01-01

    Whole genome-wide scanning for susceptibility loci based on linkage disequilibrium (LD) has been proposed as a powerful strategy for mapping common complex diseases, especially in isolated populations. We recruited 389 individuals from 175 families in the US territory of American Samoa, and 96 unrelated individuals from American Samoa and the independent country of Samoa in order to examine background LD by using a 10 centimorgan (cM) map containing 381 autosomal and 18 X-linked microsatellite markers. We tested the relationship between LD and recombination fraction by fitting a regression model. We estimated a slope of -0.021 (SE 0.00354; p < 0.0001). Based on our results, LD in the Samoan population decays steadily as the recombination fraction between autosomal markers increases. The patterns of LD observed in the Samoan population are quite similar to those previously observed in Palau but markedly contrast with those observed in a non-isolated Caucasian sample, where there is essentially no marker-to-marker LD. Our analyses support the hypothesis of a recent bottleneck, which is consistent with the known demographic history of the Samoan population. Furthermore, population substructure tests support the hypothesis that self-identified Samoans represent one homogenous genetic population. PMID:15588493

  1. Exploiting Linkage Disequilibrium for Ultrahigh-Dimensional Genome-Wide Data with an Integrated Statistical Approach.

    PubMed

    Carlsen, Michelle; Fu, Guifang; Bushman, Shaun; Corcoran, Christopher

    2016-02-01

    Genome-wide data with millions of single-nucleotide polymorphisms (SNPs) can be highly correlated due to linkage disequilibrium (LD). The ultrahigh dimensionality of big data brings unprecedented challenges to statistical modeling such as noise accumulation, the curse of dimensionality, computational burden, spurious correlations, and a processing and storing bottleneck. The traditional statistical approaches lose their power due to [Formula: see text] (n is the number of observations and p is the number of SNPs) and the complex correlation structure among SNPs. In this article, we propose an integrated distance correlation ridge regression (DCRR) approach to accommodate the ultrahigh dimensionality, joint polygenic effects of multiple loci, and the complex LD structures. Initially, a distance correlation (DC) screening approach is used to extensively remove noise, after which LD structure is addressed using a ridge penalized multiple logistic regression (LRR) model. The false discovery rate, true positive discovery rate, and computational cost were simultaneously assessed through a large number of simulations. A binary trait of Arabidopsis thaliana, the hypersensitive response to the bacterial elicitor AvrRpm1, was analyzed in 84 inbred lines (28 susceptibilities and 56 resistances) with 216,130 SNPs. Compared to previous SNP discovery methods implemented on the same data set, the DCRR approach successfully detected the causative SNP while dramatically reducing spurious associations and computational time. Copyright © 2016 by the Genetics Society of America.

  2. Genome-Wide Significant Linkage of Schizophrenia-Related Neuroanatomical Trait to 12q24

    PubMed Central

    Sprooten, Emma; Gupta, Cota Navin; Knowles, Emma EM; McKay, D Reese; Mathias, Samuel R; Curran, Joanne E; Kent, Jack W; Carless, Melanie A; Almeida, Marcio A; Dyer, Thomas D; Göring, Harald HH; Olvera, Rene L; Kochunov, Peter; Fox, Peter T; Duggirala, Ravi; Almasy, Laura; Calhoun, Vince D.; Blangero, John; Turner, Jessica A; Glahn, David C

    2015-01-01

    The insula and medial prefrontal cortex (mPFC) share functional, histological, transcriptional and developmental characteristics and they serve higher cognitive functions of theoretical relevance to schizophrenia and related disorders. Meta-analyses and multivariate analysis of structural magnetic resonance imaging (MRI) scans indicate that gray matter density and volume reductions in schizophrenia are the most consistent and pronounced in a network primarily composed of the insula and mPFC. We used source-based morphometry, a multivariate technique optimized for structural MRI, in a large sample of randomly ascertained pedigrees (N = 887) to derive an insula-mPFC component and to investigate its genetic determinants. Firstly, we replicated the insula-mPFC gray matter component as an independent source of gray matter variation in the general population, and verified its relevance to schizophrenia in an independent case-control sample. Secondly, we showed that the neuroanatomical variation defined by this component is largely determined by additive genetic variation (h2 = 0.59), and genome-wide linkage analysis resulted in a significant linkage peak at 12q24 (LOD = 3.76). This region has been of significant interest to psychiatric genetics as it contains the Darier’s disease locus and other proposed susceptibility genes (e.g. DAO, NOS1), and it has been linked to affective disorders and schizophrenia in multiple populations. Thus, in conjunction with previous clinical studies, our data imply that one or more psychiatric risk variants at 12q24 are co-inherited with reductions in mPFC and insula gray matter concentration. PMID:26440917

  3. Genome Wide Search for Biomarkers to Diagnose Yersinia Infections.

    PubMed

    Kalia, Vipin Chandra; Kumar, Prasun

    2015-12-01

    Bacterial identification on the basis of the highly conserved 16S rRNA (rrs) gene is limited by its presence in multiple copies and a very high level of similarity among them. The need is to look for other genes with unique characteristics to be used as biomarkers. Fifty-one sequenced genomes belonging to 10 different Yersinia species were used for searching genes common to all the genomes. Out of 304 common genes, 34 genes of sizes varying from 0.11 to 4.42 kb, were selected and subjected to in silico digestion with 10 different Restriction endonucleases (RE) (4-6 base cutters). Yersinia species have 6-7 copies of rrs per genome, which are difficult to distinguish by multiple sequence alignments or their RE digestion patterns. However, certain unique combinations of other common gene sequences-carB, fadJ, gluM, gltX, ileS, malE, nusA, ribD, and rlmL and their RE digestion patterns can be used as markers for identifying 21 strains belonging to 10 Yersinia species: Y. aldovae, Y. enterocolitica, Y. frederiksenii, Y. intermedia, Y. kristensenii, Y. pestis, Y. pseudotuberculosis, Y. rohdei, Y. ruckeri, and Y. similis. This approach can be applied for rapid diagnostic applications.

  4. Genome-wide linkage scan identifies two novel genetic loci for coronary artery disease: in GeneQuest families.

    PubMed

    Gao, Hanxiang; Li, Lin; Rao, Shaoqi; Shen, Gongqing; Xi, Quansheng; Chen, Shenghan; Zhang, Zheng; Wang, Kai; Ellis, Stephen G; Chen, Qiuyun; Topol, Eric J; Wang, Qing K

    2014-01-01

    Coronary artery disease (CAD) is the leading cause of death worldwide. Recent genome-wide association studies (GWAS) identified >50 common variants associated with CAD or its complication myocardial infarction (MI), but collectively they account for <20% of heritability, generating a phenomena of "missing heritability". Rare variants with large effects may account for a large portion of missing heritability. Genome-wide linkage studies of large families and follow-up fine mapping and deep sequencing are particularly effective in identifying rare variants with large effects. Here we show results from a genome-wide linkage scan for CAD in multiplex GeneQuest families with early onset CAD and MI. Whole genome genotyping was carried out with 408 markers that span the human genome by every 10 cM and linkage analyses were performed using the affected relative pair analysis implemented in GENEHUNTER. Affected only nonparametric linkage (NPL) analysis identified two novel CAD loci with highly significant evidence of linkage on chromosome 3p25.1 (peak NPL  = 5.49) and 3q29 (NPL  = 6.84). We also identified four loci with suggestive linkage on 9q22.33, 9q34.11, 17p12, and 21q22.3 (NPL  = 3.18-4.07). These results identify novel loci for CAD and provide a framework for fine mapping and deep sequencing to identify new susceptibility genes and novel variants associated with risk of CAD.

  5. Genome wide linkage disequilibrium and genetic structure in Sicilian dairy sheep breeds.

    PubMed

    Mastrangelo, Salvatore; Di Gerlando, Rosalia; Tolone, Marco; Tortorici, Lina; Sardina, Maria Teresa; Portolano, Baldassare

    2014-10-10

    The recent availability of sheep genome-wide SNP panels allows providing background information concerning genome structure in domestic animals. The aim of this work was to investigate the patterns of linkage disequilibrium (LD), the genetic diversity and population structure in Valle del Belice, Comisana, and Pinzirita dairy sheep breeds using the Illumina Ovine SNP50K Genotyping array. Average r (2) between adjacent SNPs across all chromosomes was 0.155 ± 0.204 for Valle del Belice, 0.156 ± 0.208 for Comisana, and 0.128 ± 0.188 for Pinzirita breeds, and some variations in LD value across chromosomes were observed, in particular for Valle del Belice and Comisana breeds. Average values of r (2) estimated for all pairwise combinations of SNPs pooled over all autosomes were 0.058 ± 0.023 for Valle del Belice, 0.056 ± 0.021 for Comisana, and 0.037 ± 0.017 for Pinzirita breeds. The LD declined as a function of distance and average r (2) was lower than the values observed in other sheep breeds. Consistency of results among the several used approaches (Principal component analysis, Bayesian clustering, F ST, Neighbor networks) showed that while Valle del Belice and Pinzirita breeds formed a unique cluster, Comisana breed showed the presence of substructure. In Valle del Belice breed, the high level of genetic differentiation within breed, the heterogeneous cluster in Admixture analysis, but at the same time the highest inbreeding coefficient, suggested that the breed had a wide genetic base with inbred individuals belonging to the same flock. The Sicilian breeds were characterized by low genetic differentiation and high level of admixture. Pinzirita breed displayed the highest genetic diversity (He, Ne) whereas the lowest value was found in Valle del Belice breed. This study has reported for the first time estimates of LD and genetic diversity from a genome-wide perspective in Sicilian dairy sheep breeds. Our results indicate that breeds formed non

  6. Genome-wide linkage disequilibrium and genetic diversity in five populations of Australian domestic sheep.

    PubMed

    Al-Mamun, Hawlader Abdullah; Clark, Samuel A; Kwan, Paul; Gondro, Cedric

    2015-11-24

    Knowledge of the genetic structure and overall diversity of livestock species is important to maximise the potential of genome-wide association studies and genomic prediction. Commonly used measures such as linkage disequilibrium (LD), effective population size (N e ), heterozygosity, fixation index (F ST) and runs of homozygosity (ROH) are widely used and help to improve our knowledge about genetic diversity in animal populations. The development of high-density single nucleotide polymorphism (SNP) arrays and the subsequent genotyping of large numbers of animals have greatly increased the accuracy of these population-based estimates. In this study, we used the Illumina OvineSNP50 BeadChip array to estimate and compare LD (measured by r (2) and D'), N e , heterozygosity, F ST and ROH in five Australian sheep populations: three pure breeds, i.e., Merino (MER), Border Leicester (BL), Poll Dorset (PD) and two crossbred populations i.e. F1 crosses of Merino and Border Leicester (MxB) and MxB crossed to Poll Dorset (MxBxP). Compared to other livestock species, the sheep populations that were analysed in this study had low levels of LD and high levels of genetic diversity. The rate of LD decay was greater in Merino than in the other pure breeds. Over short distances (<10 kb), the levels of LD were higher in BL and PD than in MER. Similarly, BL and PD had comparatively smaller N e than MER. Observed heterozygosity in the pure breeds ranged from 0.3 in BL to 0.38 in MER. Genetic distances between breeds were modest compared to other livestock species (highest F ST = 0.063) but the genetic diversity within breeds was high. Based on ROH, two chromosomal regions showed evidence of strong recent selection. This study shows that there is a large range of genome diversity in Australian sheep breeds, especially in Merino sheep. The observed range of diversity will influence the design of genome-wide association studies and the results that can be obtained from them. This

  7. Combined genome-wide linkage and targeted association analysis of head circumference in autism spectrum disorder families.

    PubMed

    Woodbury-Smith, M; Bilder, D A; Morgan, J; Jerominski, L; Darlington, T; Dyer, T; Paterson, A D; Coon, H

    2017-01-01

    It has long been recognized that there is an association between enlarged head circumference (HC) and autism spectrum disorder (ASD), but the genetics of HC in ASD is not well understood. In order to investigate the genetic underpinning of HC in ASD, we undertook a genome-wide linkage study of HC followed by linkage signal targeted association among a sample of 67 extended pedigrees with ASD. HC measurements on members of 67 multiplex ASD extended pedigrees were used as a quantitative trait in a genome-wide linkage analysis. The Illumina 6K SNP linkage panel was used, and analyses were carried out using the SOLAR implemented variance components model. Loci identified in this way formed the target for subsequent association analysis using the Illumina OmniExpress chip and imputed genotypes. A modification of the qTDT was used as implemented in SOLAR. We identified a linkage signal spanning 6p21.31 to 6p22.2 (maximum LOD = 3.4). Although targeted association did not find evidence of association with any SNP overall, in one family with the strongest evidence of linkage, there was evidence for association (rs17586672, p = 1.72E-07). Although this region does not overlap with ASD linkage signals in these same samples, it has been associated with other psychiatric risk, including ADHD, developmental dyslexia, schizophrenia, specific language impairment, and juvenile bipolar disorder. The genome-wide significant linkage signal represents the first reported observation of a potential quantitative trait locus for HC in ASD and may be relevant in the context of complex multivariate risk likely leading to ASD.

  8. Motor sequencing deficit as an endophenotype of speech sound disorder: A genome-wide linkage analysis in a multigenerational family

    PubMed Central

    Peter, Beate; Matsushita, Mark; Raskind, Wendy H.

    2012-01-01

    Objectives The purpose of this pilot study was to investigate a measure of motor sequencing deficit as a potential endophenotype of speech sound disorder (SSD) in a multigenerational family with evidence of familial SSD. Methods In a multigenerational family with evidence of a familial motor-based SSD, affectation status and a measure of motor sequencing during oral motor testing were obtained. To further investigate the role of motor sequencing as an endophenotype for genetic studies, parametric and nonparametric linkage analyses were conducted using a genome-wide panel of 404 microsatellites. Results In seven of the ten family members with available data, SSD affectation status and motor sequencing status coincided. Linkage analysis revealed four regions of interest, 6p21, 7q32, 7q36, and 8q24, primarily identified with the measure of motor sequencing ability. The 6p21 region overlaps with a locus implicated in rapid alternating naming in a recent genome-wide dyslexia linkage study. The 7q32 locus contains a locus implicated in dyslexia. The 7q36 locus borders on a gene known to affect component traits of language impairment. Conclusions Results are consistent with a motor-based endophenotype of SSD that would be informative for genetic studies. The linkage results in this first genome-wide study in a multigenerational family with SSD warrant follow-up in additional families and with fine mapping or next-generation approaches to gene identification. PMID:22517379

  9. Genome-wide scan for linkage to schizophrenia in a Spanish-origin cohort from Costa Rica.

    PubMed

    DeLisi, Lynn E; Mesen, Andrea; Rodriguez, Carlos; Bertheau, Arturo; LaPrade, Beatrice; Llach, Michelle; Riondet, Silvina; Razi, Kamran; Relja, Margaret; Byerley, William; Sherrington, Robin

    2002-07-08

    Genetic isolates have been useful cohorts in which to search for genes underlying disorders of unknown pathology. One such cohort is thought to exist in the Central Valley of Costa Rica surrounding the city of San Jose. Previous investigators identified a rare dominant gene for hereditary deafness in this population, and a suggestive linkage of severe bipolar psychosis has been reported in another study. Ninety-nine families with at least one pair of siblings affected with schizophrenia or a schizophrenia-spectrum diagnosis had clinical evaluations and DNA collected for genotyping. The Marshfield Medical Research Foundation (NHLBI) Mammalian Genotyping Service performed all genotyping using 404 short-tandem repeat polymorphic markers (STRPs) spaced on average 10 cM apart. Data were analyzed using the nonparametric program, GeneHunterPlus. The population structure was investigated using the STRUCT program. No region was found with genome-wide significance for linkage. Using a phenotype of schizophrenia plus schizoaffective disorder, the highest maximum likelihood score (MLS) observed was 1.78 (P < 0.004) at 176.6 cM from pter on chromosome 5q, an area previously implicated by some other groups. In addition, five regions on chromosomes 1p, 2p, 2q, 14p, and 8p had MLSs above 1.0. All other regions produced scores below 1.0. Population genetic analysis reveals no evidence for population substructure, for admixture with other populations, such as Amerindians, or for inbreeding in the parental generation. The latter casts some doubt on this population being an isolate, although there was evidence of inbreeding among the offspring.

  10. Genome-Wide Linkage Scan Identifies Two Novel Genetic Loci for Coronary Artery Disease: In GeneQuest Families

    PubMed Central

    Shen, Gongqing; Xi, Quansheng; Chen, Shenghan; Zhang, Zheng; Wang, Kai; Ellis, Stephen G.; Chen, Qiuyun; Topol, Eric J.; Wang, Qing K.

    2014-01-01

    Coronary artery disease (CAD) is the leading cause of death worldwide. Recent genome-wide association studies (GWAS) identified >50 common variants associated with CAD or its complication myocardial infarction (MI), but collectively they account for <20% of heritability, generating a phenomena of “missing heritability”. Rare variants with large effects may account for a large portion of missing heritability. Genome-wide linkage studies of large families and follow-up fine mapping and deep sequencing are particularly effective in identifying rare variants with large effects. Here we show results from a genome-wide linkage scan for CAD in multiplex GeneQuest families with early onset CAD and MI. Whole genome genotyping was carried out with 408 markers that span the human genome by every 10 cM and linkage analyses were performed using the affected relative pair analysis implemented in GENEHUNTER. Affected only nonparametric linkage (NPL) analysis identified two novel CAD loci with highly significant evidence of linkage on chromosome 3p25.1 (peak NPL  = 5.49) and 3q29 (NPL  = 6.84). We also identified four loci with suggestive linkage on 9q22.33, 9q34.11, 17p12, and 21q22.3 (NPL  = 3.18–4.07). These results identify novel loci for CAD and provide a framework for fine mapping and deep sequencing to identify new susceptibility genes and novel variants associated with risk of CAD. PMID:25485937

  11. Genome-wide Study of Families with Absolute Pitch Reveals Linkage to 8q24.21 and Locus Heterogeneity

    PubMed Central

    Theusch, Elizabeth; Basu, Analabha; Gitschier, Jane

    2009-01-01

    Absolute pitch (AP) is the rare ability to instantaneously recognize and label tones with their musical note names without using a reference pitch for comparison. The etiology of AP is complex. Prior studies have implicated both genetic and environmental factors in its genesis, yet the molecular basis for AP remains unknown. To locate regions of the human genome that may harbor AP-predisposing genetic variants, we performed a genome-wide linkage study on 73 multiplex AP families by genotyping them with 6090 SNP markers. Nonparametric multipoint linkage analyses were conducted, and the strongest evidence for linkage was observed on chromosome 8q24.21 in the subset of 45 families with European ancestry (exponential LOD score = 3.464, empirical genome-wide p = 0.03). Other regions with suggestive LOD scores included chromosomes 7q22.3, 8q21.11, and 9p21.3. Of these four regions, only the 7q22.3 linkage peak was also evident when 19 families with East Asian ancestry were analyzed separately. Though only one of these regions has yet reached statistical significance individually, we detected a larger number of independent linkage peaks than expected by chance overall, indicating that AP is genetically heterogeneous. PMID:19576568

  12. Linkage Disequilibrium And Genome-Wide Association Studies In O. sativa

    USDA-ARS?s Scientific Manuscript database

    There is increasing evidence that genome-wide association studies provide a powerful approach to find the genetic basis of complex phenotypic variation in all kinds of species. For this purpose, we developed the first generation 44K Affymetrix SNP array in rice (see Tung et al. poster). We genotyped...

  13. A comparison in association and linkage genome-wide scans for alcoholism susceptibility genes using single-nucleotide polymorphisms.

    PubMed

    Chiu, Yen-Feng; Liu, Su-Yun; Tsai, Ya-Yu

    2005-12-30

    We conducted genome-wide linkage scans using both microsatellite and single-nucleotide polymorphism (SNP) markers. Regions showing the strongest evidence of linkage to alcoholism susceptibility genes were identified. Haplotype analyses using a sliding-window approach for SNPs in these regions were performed. In addition, we performed a genome-wide association scan using SNP data. SNPs in these regions with evidence of association (P linkage (NPL) scores from SNP and microsatellite genome scans are fairly consistent; however, the peaks of the NPL scores are mostly higher in the SNP-based scan than those using microsatellite markers, which might be located at different regions. Furthermore, SNPs identified from linkage screens were not so strongly associated with alcoholism (the most significant SNP had a p-value of 0.030) as those identified from association genomic screening (the most significant SNP had a p-value of 2.0 x 10(-8)).

  14. Genome-wide association and linkage study in the Amish detects a novel candidate late-onset Alzheimer disease gene.

    PubMed

    Cummings, Anna C; Jiang, Lan; Velez Edwards, Digna R; McCauley, Jacob L; Laux, Renee; McFarland, Lynne L; Fuzzell, Denise; Knebusch, Clare; Caywood, Laura; Reinhart-Mercer, Lori; Nations, Laura; Gilbert, John R; Konidari, Ioanna; Tramontana, Michael; Cuccaro, Michael L; Scott, William K; Pericak-Vance, Margaret A; Haines, Jonathan L

    2012-09-01

    To identify novel late-onset Alzheimer disease (LOAD) risk genes, we have analysed Amish populations of Ohio and Indiana. We performed genome-wide SNP linkage and association studies on 798 individuals (109 with LOAD). We tested association using the Modified Quasi-Likelihood Score test and also performed two-point and multipoint linkage analyses. We found that LOAD was significantly associated with APOE (P= 9.0 × 10-6) in all our ascertainment regions except for the Adams County, Indiana, community (P= 0.55). Genome-wide, the most strongly associated SNP was rs12361953 (P= 7.92 × 10-7). A very strong, genome-wide significant multipoint peak [recessive heterogeneity multipoint LOD (HLOD) = 6.14, dominant HLOD = 6.05] was detected on 2p12. Three additional loci with multipoint HLOD scores >3 were detected on 3q26, 9q31 and 18p11. Converging linkage and association results, the most significantly associated SNP under the 2p12 peak was at rs2974151 (P= 1.29 × 10-4). This SNP is located in CTNNA2, which encodes catenin alpha 2, a neuronal-specific catenin known to have function in the developing brain. These results identify CTNNA2 as a novel candidate LOAD gene, and implicate three other regions of the genome as novel LOAD loci. These results underscore the utility of using family-based linkage and association analyses in isolated populations to identify novel loci for traits with complex genetic architecture. © 2012 The Authors Annals of Human Genetics © 2012 Blackwell Publishing Ltd/University College London.

  15. Genome-wide association and linkage study in the Amish detects a novel candidate late-onset Alzheimer disease gene

    PubMed Central

    Cummings, Anna C.; Jiang, Lan; Velez Edwards, Digna R.; McCauley, Jacob L.; Laux, Renee; McFarland, Lynne L.; Fuzzell, Denise; Knebusch, Clare; Caywood, Laura; Reinhart-Mercer, Lori; Nations, Laura; Gilbert, John R.; Konidari, Ioanna; Tramontana, Michael; Cuccaro, Michael L.; Scott, William K.; Pericak-Vance, Margaret A.; Haines, Jonathan L.

    2012-01-01

    Summary To identify novel late-onset Alzheimer disease (LOAD) risk genes, we have analyzed Amish populations of Ohio and Indiana. We performed genome-wide SNP linkage and association studies on 798 individuals (109 with LOAD). We tested association using the Modified Quasi-Likelihood Score (MQLS) test and also performed two-point and multipoint linkage analyses. We found that LOAD was significantly associated with APOE (P=9.0×10-6) in all our ascertainment regions except for the Adams County, Indiana, community (P=0.55). Genome-wide, the most strongly associated SNP was rs12361953 (P=7.92×10-7). A very strong, genome-wide significant multipoint peak (recessive HLOD=6.14, dominant HLOD=6.05) was detected on 2p12. Three additional loci with multipoint HLOD scores >3 were detected on 3q26, 9q31, and 18p11. Converging linkage and association results, the most significantly associated SNP under the 2p12 peak was at rs2974151 (P=1.29×10-4). This SNP is located in CTNNA2, which encodes catenin alpha 2, a neuronal-specific catenin known to have function in the developing brain. These results identify CTNNA2 as a novel candidate LOAD gene, and implicate three other regions of the genome as novel LOAD loci. These results underscore the utility of using family-based linkage and association analysis in isolated populations to identify novel loci for traits with complex genetic architecture. PMID:22881374

  16. Genome-wide Linkage Scan of Antisocial Behavior, Depression and Impulsive Substance Use in the UCSF Family Alcoholism Study

    PubMed Central

    Gizer, Ian R.; Ehlers, Cindy L.; Vieten, Cassandra; Feiler, Heidi S.; Gilder, David A.; Wilhelmsen, Kirk C.

    2012-01-01

    OBJECTIVE Epidemiological and clinical studies suggest that rates of antisocial behavior, depression, and impulsive substance use are increased among individuals diagnosed with alcohol dependence relative to those who are not. Thus, the present study conducted genome-wide linkage scans of antisocial behavior, depression, and impulsive substance use in the University of California at San Francisco Family Alcoholism Study. METHODS Antisocial behavior, depressive symptoms, and impulsive substance use were assessed using three scales from the MMPI-2, the Antisocial Practices content scale (ASP), the Depression content scale (DEP), and the revised MacAndrew Alcoholism scale (MAC-R). Linkage analyses were conducted using a variance components approach. RESULTS Suggestive evidence of linkage to three genomic regions independent of alcohol and cannabis dependence diagnostic status was observed: the ASP scale showed evidence of linkage to chromosome 13 at 11 cM, the MAC-R scale showed evidence of linkage to chromosome 15 at 47 cM, and all 3 scales showed evidence of linkage to chromosome 17 at 57–58 cM. CONCLUSIONS Each of these regions has shown prior evidence of linkage and association to substance dependence as well as other psychiatric disorders such as mood and anxiety disorders, ADHD, and schizophrenia thus suggesting potentially broad relations between these regions and psychopathology. PMID:22517380

  17. Genome-wide linkage scan of antisocial behavior, depression, and impulsive substance use in the UCSF family alcoholism study.

    PubMed

    Gizer, Ian R; Ehlers, Cindy L; Vieten, Cassandra; Feiler, Heidi S; Gilder, David A; Wilhelmsen, Kirk C

    2012-10-01

    Epidemiological and clinical studies suggest that the rates of antisocial behavior, depression, and impulsive substance use are increased among individuals diagnosed with alcohol dependence relative to those who are not. Thus, the present study conducted genome-wide linkage scans of antisocial behavior, depression, and impulsive substance use in the University of California at San Francisco Family Alcoholism Study. Antisocial behavior, depressive symptoms, and impulsive substance use were assessed using three scales from the Minnesota Multiphasic Personality Inventory - 2nd ed.: the Antisocial Practices content scale, the Depression content scale, and the revised MacAndrew Alcoholism scale. Linkage analyses were carried out using a variance components approach. Suggestive evidence of linkage to three genomic regions independent of alcohol and cannabis dependence diagnostic status was observed: the Antisocial Practices content scale showed evidence of linkage to chromosome 13 at 11 cM, the MacAndrew Alcoholism scale showed evidence of linkage to chromosome 15 at 47 cM, and all three scales showed evidence of linkage to chromosome 17 at 57-58 cM. Each of these regions has shown previous evidence of linkage and association to substance dependence as well as other psychiatric disorders such as mood and anxiety disorders, attention-deficit hyperactivity disorder, and schizophrenia, thus suggesting potentially broad relations between these regions and psychopathology.

  18. Genome-wide search for genes affecting the risk for alcohol dependence.

    PubMed

    Reich, T; Edenberg, H J; Goate, A; Williams, J T; Rice, J P; Van Eerdewegh, P; Foroud, T; Hesselbrock, V; Schuckit, M A; Bucholz, K; Porjesz, B; Li, T K; Conneally, P M; Nurnberger, J I; Tischfield, J A; Crowe, R R; Cloninger, C R; Wu, W; Shears, S; Carr, K; Crose, C; Willig, C; Begleiter, H

    1998-05-08

    Alcohol dependence is a leading cause of morbidity and premature death. Several lines of evidence suggest a substantial genetic component to the risk for alcoholism: sibs of alcoholic probands have a 3-8 fold increased risk of also developing alcoholism, and twin heritability estimates of 50-60% are reported by contemporary studies of twins. We report on the results of a six-center collaborative study to identify susceptibility loci for alcohol dependence. A genome-wide screen examined 291 markers in 987 individuals from 105 families. Two-point and multipoint nonparametric linkage analyses were performed to detect susceptibility loci for alcohol dependence. Multipoint methods provided the strongest suggestions of linkage with susceptibility loci for alcohol dependence on chromosomes 1 and 7, and more modest evidence for a locus on chromosome 2. In addition, there was suggestive evidence for a protective locus on chromosome 4 near the alcohol dehydrogenase genes, for which protective effects have been reported in Asian populations.

  19. A large-scale genome-wide linkage analysis to map loci linked to stature in Chinese population.

    PubMed

    Hong, Xiumei; Tsai, Hui-Ju; Liu, Xin; Li, Zhiping; Liu, Xue; Tang, Genfu; Xing, Houxun; Yang, Jianhua; Wang, Binyan; Feng, Yan; Xu, Xin; Xu, Xiping; Wang, Xiaobin

    2008-11-01

    A number of genome-wide scans of stature have been reported previously, but with inconsistent results. The inconsistency may be partly due to differential population characteristics and gender- and/or age-specific effects on this trait. This study aimed to identify the quantitative trait loci (QTLs) underlying the variation of stature in Chinese population, and to evaluate age- and gender-specific linkage for stature. We conducted a large-scale, genome-wide linkage scan using the data from three independent samples (a total of 7112 subjects from 1811 pedigrees) enrolled from the same geographical region in China. Linkage analyses were performed in the pooled samples and in subgroups defined by age (25 yr), gender, or both, using the model-free regression method implemented in MERLIN-REGRESS. The strongest linkage signal was obtained on 17q24 (LOD=3.82) in the pooled samples. Age-specific analysis revealed two additional significant QTLs on 13q34 and 18p11.3 among subjects 25 yr or younger. In gender-specific analyses, males showed suggestive QTLs on 12q21 (LOD=2.31) and 17q22 (LOD=2.60), and females showed a suggestive QTL on 13q31.1 (LOD=2.68). Age- and gender-specific linkage analyses suggested that males older than 25 yr contributed more signals to QTLs on 12q21 and 17q22, with a LOD score of 3.00 and 2.26, respectively, whereas females older than 25 yr presented a suggestive QTL on 8q24.3 (LOD=2.57). Our study identified a strong linkage of chromosome 17q24 to stature in this Chinese population, and indicated that it may be informative to consider differential age and gender effects in the genetic dissection of stature.

  20. Genome-wide linkage scan for contraction velocity characteristics of knee musculature in the Leuven Genes for Muscular Strength Study.

    PubMed

    De Mars, Gunther; Windelinckx, An; Huygens, Wim; Peeters, Maarten W; Beunen, Gaston P; Aerssens, Jeroen; Vlietinck, Robert; Thomis, Martine A I

    2008-09-17

    The torque-velocity relationship is known to be affected by ageing, decreasing its protective role in the prevention of falls. Interindividual variability in this torque-velocity relationship is partly determined by genetic factors (h(2): 44-67%). As a first attempt, this genome-wide linkage study aimed to identify chromosomal regions linked to the torque-velocity relationship of the knee flexors and extensors. A selection of 283 informative male siblings (17-36 yr), belonging to 105 families, was used to conduct a genome-wide SNP-based (Illumina Linkage IVb panel) multipoint linkage analysis for the torque-velocity relationship of the knee flexors and extensors. The strongest evidence for linkage was found at 15q23 for the torque-velocity slope of the knee extensors (TVSE). Other interesting linkage regions with LOD scores >2 were found at 7p12.3 [logarithm of the odds ratio (LOD) = 2.03, P = 0.0011] for the torque-velocity ratio of the knee flexors (TVRF), at 2q14.3 (LOD = 2.25, P = 0.0006) for TVSE, and at 4p14 and 18q23 for the torque-velocity ratio of the knee extensors TVRE (LOD = 2.23 and 2.08; P = 0.0007 and 0.001, respectively). We conclude that many small contributing genes are involved in causing variation in the torque-velocity relationship of the knee flexor and extensor muscles. Several earlier reported candidate genes for muscle strength and muscle mass and new candidates are harbored within or in close vicinity of the linkage regions reported in the present study.

  1. Genome-Wide Divergence and Linkage Disequilibrium Analyses for Capsicum baccatum Revealed by Genome-Anchored Single Nucleotide Polymorphisms.

    PubMed

    Nimmakayala, Padma; Abburi, Venkata L; Saminathan, Thangasamy; Almeida, Aldo; Davenport, Brittany; Davidson, Joshua; Reddy, C V Chandra Mohan; Hankins, Gerald; Ebert, Andreas; Choi, Doil; Stommel, John; Reddy, Umesh K

    2016-01-01

    Principal component analysis (PCA) with 36,621 polymorphic genome-anchored single nucleotide polymorphisms (SNPs) identified collectively for Capsicum annuum and Capsicum baccatum was used to characterize population structure and species domestication of these two important incompatible cultivated pepper species. Estimated mean nucleotide diversity (π) and Tajima's D across various chromosomes revealed biased distribution toward negative values on all chromosomes (except for chromosome 4) in cultivated C. baccatum, indicating a population bottleneck during domestication of C. baccatum. In contrast, C. annuum chromosomes showed positive π and Tajima's D on all chromosomes except chromosome 8, which may be because of domestication at multiple sites contributing to wider genetic diversity. For C. baccatum, 13,129 SNPs were available, with minor allele frequency (MAF) ≥0.05; PCA of the SNPs revealed 283 C. baccatum accessions grouped into 3 distinct clusters, for strong population structure. The fixation index (FST ) between domesticated C. annuum and C. baccatum was 0.78, which indicates genome-wide divergence. We conducted extensive linkage disequilibrium (LD) analysis of C. baccatum var. pendulum cultivars on all adjacent SNP pairs within a chromosome to identify regions of high and low LD interspersed with a genome-wide average LD block size of 99.1 kb. We characterized 1742 haplotypes containing 4420 SNPs (range 9-2 SNPs per haplotype). Genome-wide association study (GWAS) of peduncle length, a trait that differentiates wild and domesticated C. baccatum types, revealed 36 significantly associated genome-wide SNPs. Population structure, identity by state (IBS) and LD patterns across the genome will be of potential use for future GWAS of economically important traits in C. baccatum peppers.

  2. Genome-Wide Divergence and Linkage Disequilibrium Analyses for Capsicum baccatum Revealed by Genome-Anchored Single Nucleotide Polymorphisms

    PubMed Central

    Nimmakayala, Padma; Abburi, Venkata L.; Saminathan, Thangasamy; Almeida, Aldo; Davenport, Brittany; Davidson, Joshua; Reddy, C. V. Chandra Mohan; Hankins, Gerald; Ebert, Andreas; Choi, Doil; Stommel, John; Reddy, Umesh K.

    2016-01-01

    Principal component analysis (PCA) with 36,621 polymorphic genome-anchored single nucleotide polymorphisms (SNPs) identified collectively for Capsicum annuum and Capsicum baccatum was used to characterize population structure and species domestication of these two important incompatible cultivated pepper species. Estimated mean nucleotide diversity (π) and Tajima's D across various chromosomes revealed biased distribution toward negative values on all chromosomes (except for chromosome 4) in cultivated C. baccatum, indicating a population bottleneck during domestication of C. baccatum. In contrast, C. annuum chromosomes showed positive π and Tajima's D on all chromosomes except chromosome 8, which may be because of domestication at multiple sites contributing to wider genetic diversity. For C. baccatum, 13,129 SNPs were available, with minor allele frequency (MAF) ≥0.05; PCA of the SNPs revealed 283 C. baccatum accessions grouped into 3 distinct clusters, for strong population structure. The fixation index (FST) between domesticated C. annuum and C. baccatum was 0.78, which indicates genome-wide divergence. We conducted extensive linkage disequilibrium (LD) analysis of C. baccatum var. pendulum cultivars on all adjacent SNP pairs within a chromosome to identify regions of high and low LD interspersed with a genome-wide average LD block size of 99.1 kb. We characterized 1742 haplotypes containing 4420 SNPs (range 9–2 SNPs per haplotype). Genome-wide association study (GWAS) of peduncle length, a trait that differentiates wild and domesticated C. baccatum types, revealed 36 significantly associated genome-wide SNPs. Population structure, identity by state (IBS) and LD patterns across the genome will be of potential use for future GWAS of economically important traits in C. baccatum peppers. PMID:27857720

  3. Genome-Wide Linkage Scan for Primary Open Angle Glaucoma: Influences of Ancestry and Age at Diagnosis

    PubMed Central

    Qin, Xuejun; Liu, Yutao; Gibson, Jason R.; Santiago-Turla, Cecilia; Larocque-Abramson, Karen R.; Del Bono, Elizabeth; Challa, Pratap; Herndon, Leon W.; Akafo, Stephen; Wiggs, Janey L.; Schmidt, Silke; Hauser, Michael A.

    2011-01-01

    Primary open-angle glaucoma (POAG) is the most common form of glaucoma and one of the leading causes of vision loss worldwide. The genetic etiology of POAG is complex and poorly understood. The purpose of this work is to identify genomic regions of interest linked to POAG. This study is the largest genetic linkage study of POAG performed to date: genomic DNA samples from 786 subjects (538 Caucasian ancestry, 248 African ancestry) were genotyped using either the Illumina GoldenGate Linkage 4 Panel or the Illumina Infinium Human Linkage-12 Panel. A total of 5233 SNPs was analyzed in 134 multiplex POAG families (89 Caucasian ancestry, 45 African ancestry). Parametric and non-parametric linkage analyses were performed on the overall dataset and within race-specific datasets (Caucasian ancestry and African ancestry). Ordered subset analysis was used to stratify the data on the basis of age of glaucoma diagnosis. Novel linkage regions were identified on chromosomes 1 and 20, and two previously described loci—GLC1D on chromosome 8 and GLC1I on chromosome 15—were replicated. These data will prove valuable in the context of interpreting results from genome-wide association studies for POAG. PMID:21765929

  4. A Genome Wide Linkage Scan for Cleft Lip and Palate and Dental Anomalies

    PubMed Central

    Vieira, Alexandre R.; McHenry, Toby G.; Daack-Hirsch, Sandra; Murray, Jeffrey C.; Marazita, Mary L.

    2008-01-01

    We revisited 46 families with two or more siblings affected with an orofacial cleft that participated in previous genome wide studies and collected complete dental information. Genotypes from 392 microsatellite markers at 10 cM intervals were reanalyzed. We carried out four sets of genome wide analyses. First, we ran the analysis solely on the cleft status. Second, we assigned to any dental anomaly (tooth agenesis, supernumerary teeth, and microdontia) an affection status, and repeated the analysis. Third, we ran only the 19 families where the proband had a cleft with no dental anomalies. Finally, we ran only the 27 families that had a proband with cleft and additional dental anomalies outside the cleft area. Chromosomes (1, 2, 6, 8, 16, and 19) presented regions with LOD scores >2.0. Chromosome 19 has the most compelling results in our study. The LOD scores increased from 3.11 (in the scan of all 46 families with clefts as the only assigned affection status) to 3.91 when the 19 families whose probands present with no additional dental anomalies were studied, suggesting the interval 19p13.12-19q12 may contain a gene that contributes to clefts but not to dental anomalies. On the other hand, we found a LOD score of 3.00 in the 2q22.3 region when dental anomalies data were added to the analysis to define affection status. Our preliminary results support the hypothesis that some loci may contribute to both clefts and congenital dental anomalies. Also, adding dental anomalies information will provide new opportunities to map susceptibility loci for clefts. PMID:18442096

  5. A genome wide linkage scan for cleft lip and palate and dental anomalies.

    PubMed

    Vieira, Alexandre R; McHenry, Toby G; Daack-Hirsch, Sandra; Murray, Jeffrey C; Marazita, Mary L

    2008-06-01

    We revisited 46 families with two or more siblings affected with an orofacial cleft that participated in previous genome wide studies and collected complete dental information. Genotypes from 392 microsatellite markers at 10 cM intervals were reanalyzed. We carried out four sets of genome wide analyses. First, we ran the analysis solely on the cleft status. Second, we assigned to any dental anomaly (tooth agenesis, supernumerary teeth, and microdontia) an affection status, and repeated the analysis. Third, we ran only the 19 families where the proband had a cleft with no dental anomalies. Finally, we ran only the 27 families that had a proband with cleft and additional dental anomalies outside the cleft area. Chromosomes (1, 2, 6, 8, 16, and 19) presented regions with LOD scores >2.0. Chromosome 19 has the most compelling results in our study. The LOD scores increased from 3.11 (in the scan of all 46 families with clefts as the only assigned affection status) to 3.91 when the 19 families whose probands present with no additional dental anomalies were studied, suggesting the interval 19p13.12-19q12 may contain a gene that contributes to clefts but not to dental anomalies. On the other hand, we found a LOD score of 3.00 in the 2q22.3 region when dental anomalies data were added to the analysis to define affection status. Our preliminary results support the hypothesis that some loci may contribute to both clefts and congenital dental anomalies. Also, adding dental anomalies information will provide new opportunities to map susceptibility loci for clefts.

  6. Common variants in the JAZF1 gene associated with height identified by linkage and genome-wide association analysis

    PubMed Central

    Johansson, Åsa; Marroni, Fabio; Hayward, Caroline; Franklin, Christopher S.; Kirichenko, Anatoly V.; Jonasson, Inger; Hicks, Andrew A.; Vitart, Veronique; Isaacs, Aaron; Axenovich, Tatiana; Campbell, Susan; Dunlop, Malcolm G.; Floyd, Jamie; Hastie, Nick; Hofman, Albert; Knott, Sara; Kolcic, Ivana; Pichler, Irene; Polasek, Ozren; Rivadeneira, Fernando; Tenesa, Albert; Uitterlinden, André G.; Wild, Sarah H.; Zorkoltseva, Irina V.; Meitinger, Thomas; Wilson, James F.; Rudan, Igor; Campbell, Harry; Pattaro, Cristian; Pramstaller, Peter; Oostra, Ben A.; Wright, Alan F.; van Duijn, Cornelia M.; Aulchenko, Yurii S.; Gyllensten, Ulf

    2009-01-01

    Genes for height have gained interest for decades, but only recently have candidate genes started to be identified. We have performed linkage analysis and genome-wide association for height in approximately 4000 individuals from five European populations. A total of five chromosomal regions showed suggestive linkage and in one of these regions, two SNPs (rs849140 and rs1635852) were associated with height (nominal P = 7.0 × 10−8 and P = 9.6 × 10−7, respectively). In total, five SNPs across the genome showed an association with height that reached the threshold of genome-wide significance (nominal P < 1.6 × 10−7). The association with height was replicated for two SNPs (rs1635852 and rs849140) using three independent studies (n = 31 077, n=1268 and n = 5746) with overall meta P-values of 9.4 × 10−10 and 5.3 × 10−8. These SNPs are located in the JAZF1 gene, which has recently been associated with type II diabetes, prostate and endometrial cancer. JAZF1 is a transcriptional repressor of NR2C2, which results in low IGF1 serum concentrations, perinatal and early postnatal hypoglycemia and growth retardation when knocked out in mice. Both the linkage and association analyses independently identified the JAZF1 region affecting human height. We have demonstrated, through replication in additional independent populations, the consistency of the effect of the JAZF1 SNPs on height. Since this gene also has a key function in the metabolism of growth, JAZF1 represents one of the strongest candidates influencing human height identified so far. PMID:18952825

  7. Genome-wide linkage analysis of the tracking of systolic blood pressure using a mixed model

    PubMed Central

    Wang, Tao; Zhu, Guohua; Keen, Kevin J

    2003-01-01

    Background Elevated blood pressure in middle age is a major risk factor for subsequent cardiovascular complications. An important longitudinal characteristic of blood pressure is the "tracking phenomenon". Tracking is defined as the persistence of the rank of a person's blood pressure level in a group over a long period of time. In this analysis, we used the Framingham data to investigate whether there are some genes responsible for this phenomenon. Results Both two-point and multipoint linkage analyses were applied to family members with complete data only and to all family data with missing values imputed by a Gaussian model. The results of two-point linkage analysis indicated that two loci for linkage with the intercept were on chromosomes 10 and 13, and two loci for linkage with both slope and intercept were on chromosomes 1 and 3. Multipoint linkage analysis indicated only one region, 200–240 cM on chromosome 1, to be linked with both intercept and slope. For the intercept of SBP, the highest LOD (4.43) was found at 214 cM when missing data were imputed, and the highest LOD (2.81) was at 231 cM for the complete case data. For the slope of SBP, the highest multipoint LODs were 3.63 at 227 cM and 2.02 at 234 cM for the complete case data and imputation data, respectively. Conclusion One or more genes in the range of 200–240 cM on chromosome 1 may be related to the tracking phenomenon of SBP. PMID:14975156

  8. Genome-Wide Linkage and Association Analysis Identifies Major Gene Loci for Guttural Pouch Tympany in Arabian and German Warmblood Horses

    PubMed Central

    Metzger, Julia; Ohnesorge, Bernhard; Distl, Ottmar

    2012-01-01

    Equine guttural pouch tympany (GPT) is a hereditary condition affecting foals in their first months of life. Complex segregation analyses in Arabian and German warmblood horses showed the involvement of a major gene as very likely. Genome-wide linkage and association analyses including a high density marker set of single nucleotide polymorphisms (SNPs) were performed to map the genomic region harbouring the potential major gene for GPT. A total of 85 Arabian and 373 German warmblood horses were genotyped on the Illumina equine SNP50 beadchip. Non-parametric multipoint linkage analyses showed genome-wide significance on horse chromosomes (ECA) 3 for German warmblood at 16–26 Mb and 34–55 Mb and for Arabian on ECA15 at 64–65 Mb. Genome-wide association analyses confirmed the linked regions for both breeds. In Arabian, genome-wide association was detected at 64 Mb within the region with the highest linkage peak on ECA15. For German warmblood, signals for genome-wide association were close to the peak region of linkage at 52 Mb on ECA3. The odds ratio for the SNP with the highest genome-wide association was 0.12 for the Arabian. In conclusion, the refinement of the regions with the Illumina equine SNP50 beadchip is an important step to unravel the responsible mutations for GPT. PMID:22848553

  9. Genome-wide linkage and association analysis identifies major gene loci for guttural pouch tympany in Arabian and German warmblood horses.

    PubMed

    Metzger, Julia; Ohnesorge, Bernhard; Distl, Ottmar

    2012-01-01

    Equine guttural pouch tympany (GPT) is a hereditary condition affecting foals in their first months of life. Complex segregation analyses in Arabian and German warmblood horses showed the involvement of a major gene as very likely. Genome-wide linkage and association analyses including a high density marker set of single nucleotide polymorphisms (SNPs) were performed to map the genomic region harbouring the potential major gene for GPT. A total of 85 Arabian and 373 German warmblood horses were genotyped on the Illumina equine SNP50 beadchip. Non-parametric multipoint linkage analyses showed genome-wide significance on horse chromosomes (ECA) 3 for German warmblood at 16-26 Mb and 34-55 Mb and for Arabian on ECA15 at 64-65 Mb. Genome-wide association analyses confirmed the linked regions for both breeds. In Arabian, genome-wide association was detected at 64 Mb within the region with the highest linkage peak on ECA15. For German warmblood, signals for genome-wide association were close to the peak region of linkage at 52 Mb on ECA3. The odds ratio for the SNP with the highest genome-wide association was 0.12 for the Arabian. In conclusion, the refinement of the regions with the Illumina equine SNP50 beadchip is an important step to unravel the responsible mutations for GPT.

  10. Systematic, genome-wide, sex-specific linkage of cardiovascular traits in French Canadians.

    PubMed

    Seda, Ondrej; Tremblay, Johanne; Gaudet, Daniel; Brunelle, Pierre-Luc; Gurau, Alexandru; Merlo, Ettore; Pilote, Louise; Orlov, Sergei N; Boulva, Francis; Petrovich, Milan; Kotchen, Theodore A; Cowley, Allen W; Hamet, Pavel

    2008-04-01

    The sexual dimorphism of cardiovascular traits, as well as susceptibility to a variety of related diseases, has long been recognized, yet their sex-specific genomic determinants are largely unknown. We systematically assessed the sex-specific heritability and linkage of 539 hemodynamic, metabolic, anthropometric, and humoral traits in 120 French-Canadian families from the Saguenay-Lac-St-Jean region of Quebec, Canada. We performed multipoint linkage analysis using microsatellite markers followed by peak-wide linkage scan based on Affymetrix Human Mapping 50K Array Xba240 single nucleotide polymorphism genotypes in 3 settings, including the entire sample and then separately in men and women. Nearly one half of the traits were age and sex independent, one quarter were both age and sex dependent, and one eighth were exclusively age or sex dependent. Sex-specific phenotypes are most frequent in heart rate and blood pressure categories, whereas sex- and age-independent determinants are predominant among humoral and biochemical parameters. Twenty sex-specific loci passing multiple testing criteria were corroborated by 2-point single nucleotide polymorphism linkage. Several resting systolic blood pressure measurements showed significant genotype-by-sex interaction, eg, male-specific locus at chromosome 12 (male-female logarithm of odds difference: 4.16; interaction P=0.0002), which was undetectable in the entire population, even after adjustment for sex. Detailed interrogation of this locus revealed a 220-kb block overlapping parts of TAO-kinase 3 and SUDS3 genes. In summary, a large number of complex cardiovascular traits display significant sexual dimorphism, for which we have demonstrated genomic determinants at the haplotype level. Many of these would have been missed in a traditional, sex-adjusted setting.

  11. Classification and Regression Tree and Spatial Analyses Reveal Geographic Heterogeneity in Genome Wide Linkage Study of Indian Visceral Leishmaniasis

    PubMed Central

    Rai, Madhukar; Singh, Shri Prakash; O'Leary, Rebecca A.; Ball, Stephen; Francis, Richard W.; Firth, Martin J.; Radford, Ben T.; Miller, E. Nancy; Sundar, Shyam; Blackwell, Jenefer M.

    2010-01-01

    Background Genome wide linkage studies (GWLS) have provided evidence for loci controlling visceral leishmaniasis on Chromosomes 1p22, 6q27, 22q12 in Sudan and 6q27, 9p21, 17q11-q21 in Brazil. Genome wide studies from the major focus of disease in India have not previously been reported. Methods and Findings We undertook a GWLS in India in which a primary ∼10 cM (515 microsatellites) scan was carried out in 58 multicase pedigrees (74 nuclear families; 176 affected, 353 total individuals) and replication sought in 79 pedigrees (102 nuclear families; 218 affected, 473 total individuals). The primary scan provided evidence (≥2 adjacent markers allele-sharing LOD≥0.59; nominal P≤0.05) for linkage on Chromosomes 2, 5, 6, 7, 8, 10, 11, 20 and X, with peaks at 6p25.3-p24.3 and 8p23.1-p21.3 contributed to largely by 31 Hindu families and at Xq21.1-q26.1 by 27 Muslim families. Refined mapping confirmed linkage across all primary scan families at 2q12.2-q14.1 and 11q13.2-q23.3, but only 11q13.2-q23.3 replicated (combined LOD = 1.59; P = 0.0034). Linkage at 6p25.3-p24.3 and 8p23.1-p21.3, and at Xq21.1-q26.1, was confirmed by refined mapping for primary Hindu and Muslim families, respectively, but only Xq21.1-q26.1 replicated across all Muslim families (combined LOD 1.49; P = 0.0045). STRUCTURE and SMARTPCA did not identify population genetic substructure related to religious group. Classification and regression tree, and spatial interpolation, analyses confirm geographical heterogeneity for linkages at 6p25.3-p24.3, 8p23.1-p21.3 and Xq21.1-q26.1, with specific clusters of families contributing LOD scores of 2.13 (P = 0.0009), 1.75 (P = 0.002) and 1.84 (P = 0.001), respectively. Conclusions GWLS has identified novel loci that show geographical heterogeneity in their influence on susceptibility to VL in India. PMID:21209823

  12. Estimates of linkage disequilibrium and effective population sizes in Chinese Merino (Xinjiang type) sheep by genome-wide SNPs.

    PubMed

    Liu, Shudong; He, Sangang; Chen, Lei; Li, Wenrong; Di, Jiang; Liu, Mingjun

    2017-01-01

    Knowledge of linkage disequilibrium (LD) is important for effective genome-wide association studies and accurate genomic prediction. Chinese Merino (Xinjiang type) is well-known fine wool sheep breed. However, the extent of LD across the genome remains unexplored. In this study, we calculated autosomal LD based on genome-wide SNPs of 635 Chinese Merino (Xinjiang type) sheep by Illumina Ovine SNP50 BeadChip. A moderate level of LD (r(2) ≥ 0.25) across the whole genome was observed at short distances of 0-10 kb. Further, the ancestral effective population size (Ne ) was analyzed by extent of LD and found that Ne increased with the increase of generations and declined rapidly within the most recent 50 generations, which is consistent with the history of Chinese Merino sheep breeding, initiated in 1971. We also noted that even when the effective population size was estimated across different single chromosomes, Ne only ranged from 140.36 to 183.33 at five generations in the past, exhibiting a rapid decrease compared with that at ten generations in the past. These results indicated that the genetic diversity in Chinese Merino sheep recently decreased and proper protective measures should be taken to maintain the diversity. Our datasets provided essential genetic information to track molecular variations which potentially contribute to phenotypic variation in Chinese Merino sheep.

  13. A genome-wide linkage scan provides evidence for both new and previously reported loci influencing common migraine.

    PubMed

    Ligthart, Lannie; Nyholt, Dale R; Hottenga, Jouke-Jan; Distel, Marijn A; Willemsen, Gonneke; Boomsma, Dorret I

    2008-10-05

    Latent class analysis was performed on migraine symptom data collected in a Dutch population sample (N = 12,210, 59% female) in order to obtain empirical groupings of individuals suffering from symptoms of migraine headache. Based on these heritable groupings (h(2) = 0.49, 95% CI: 0.41-0.57) individuals were classified as affected (migrainous headache) or unaffected. Genome-wide linkage analysis was performed using genotype data from 105 families with at least 2 affected siblings. In addition to this primary phenotype, linkage analyses were performed for the individual migraine symptoms. Significance levels, corrected for the analysis of multiple traits, were determined empirically via a novel simulation approach. Suggestive linkage for migrainous headache was found on chromosomes 1 (LOD = 1.63; pointwise P = 0.0031), 13 (LOD = 1.63; P = 0.0031), and 20 (LOD = 1.85; P = 0.0018). Interestingly, the chromosome 1 peak was located close to the ATP1A2 gene, associated with familial hemiplegic migraine type 2 (FHM2). Individual symptom analysis produced a LOD score of 1.97 (P = 0.0013) on chromosome 5 (photo/phonophobia), a LOD score of 2.13 (P = 0.0009) on chromosome 10 (moderate/severe pain intensity) and a near significant LOD score of 3.31 (P = 0.00005) on chromosome 13 (pulsating headache). These peaks were all located near regions previously reported in migraine linkage studies. Our results provide important replication and support for the presence of migraine susceptibility genes within these regions, and further support the utility of an LCA-based phenotyping approach and analysis of individual symptoms in migraine genetic research. Additionally, our novel "2-step" analysis and simulation approach provides a powerful means to investigate linkage to individual trait components.

  14. Genome-wide linkage and peak-wide association study of obesity-related quantitative traits in Caribbean Hispanics.

    PubMed

    Dong, Chuanhui; Beecham, Ashley; Slifer, Susan; Wang, Liyong; McClendon, Mark S; Blanton, Susan H; Rundek, Tatjana; Sacco, Ralph L

    2011-02-01

    Although obesity is more prevalent in Hispanics than non-Hispanic whites in the United States, little is known about the genetic etiology of the related traits in this population. To identify genetic loci influencing obesity in non-Mexican Hispanics, we performed a genome-wide linkage scan in 1,390 subjects from 100 Caribbean Hispanic families on six obesity-related quantitative traits: body mass index (BMI), body weight, waist circumference, waist-to-hip ratio, abdominal and average triceps skinfold thickness after adjusting for significant demographic and lifestyle factors. We then carried out an association analysis of the linkage peaks and the FTO gene in an independent community-based Hispanic subcohort (N = 652, 64% Caribbean Hispanics) from the Northern Manhattan Study. Evidence of linkage was strongest on 1q43 with multipoint LOD score of 2.45 (p = 0.0004) for body weight. Suggestive linkage evidence of LOD > 2.0 was also identified on 1q43 for BMI (LOD = 2.03), 14q32 for abdominal skinfold thickness (LOD = 2.17), 16p12 for BMI (LOD = 2.27) and weight (LOD = 2.26), and 16q23-24 for average triceps skinfold thickness (LOD = 2.32). In the association analysis of 6,440 single nucleotide polymorphisms (SNPs) under 1-LOD unit down regions of our linkage peaks on chromosome 1q43 and 16p12 as well as in the FTO gene, we found that two SNPs (rs6665519 and rs669231) on 1q43 and one FTO SNP (rs12447427) were significantly associated with BMI or body weight after adjustment for multiple testing. Our results suggest that in addition to FTO, multiple genetic loci, particularly those on 1q43 region, may contribute to the variations in obesity-related quantitative traits in Caribbean Hispanics.

  15. Nonlinear Analysis of Time Series in Genome-Wide Linkage Disequilibrium Data

    NASA Astrophysics Data System (ADS)

    Hernández-Lemus, Enrique; Estrada-Gil, Jesús K.; Silva-Zolezzi, Irma; Fernández-López, J. Carlos; Hidalgo-Miranda, Alfredo; Jiménez-Sánchez, Gerardo

    2008-02-01

    The statistical study of large scale genomic data has turned out to be a very important tool in population genetics. Quantitative methods are essential to understand and implement association studies in the biomedical and health sciences. Nevertheless, the characterization of recently admixed populations has been an elusive problem due to the presence of a number of complex phenomena. For example, linkage disequilibrium structures are thought to be more complex than their non-recently admixed population counterparts, presenting the so-called ancestry blocks, admixed regions that are not yet smoothed by the effect of genetic recombination. In order to distinguish characteristic features for various populations we have implemented several methods, some of them borrowed or adapted from the analysis of nonlinear time series in statistical physics and quantitative physiology. We calculate the main fractal dimensions (Kolmogorov's capacity, information dimension and correlation dimension, usually named, D0, D1 and D2). We also have made detrended fluctuation analysis and information based similarity index calculations for the probability distribution of correlations of linkage disequilibrium coefficient of six recently admixed (mestizo) populations within the Mexican Genome Diversity Project [1] and for the non-recently admixed populations in the International HapMap Project [2]. Nonlinear correlations showed up as a consequence of internal structure within the haplotype distributions. The analysis of these correlations as well as the scope and limitations of these procedures within the biomedical sciences are discussed.

  16. Genome-wide search for eliminylating domains reveals novel function for BLES03-like proteins.

    PubMed

    Khater, Shradha; Mohanty, Debasisa

    2014-07-24

    Bacterial phosphothreonine lyases catalyze a novel posttranslational modification involving formation of dehydrobutyrine/dehyroalanine by β elimination of the phosphate group of phosphothreonine or phosphoserine residues in their substrate proteins. Though there is experimental evidence for presence of dehydro amino acids in human proteins, no eukaryotic homologs of these lyases have been identified as of today. A comprehensive genome-wide search for identifying phosphothreonine lyase homologs in eukaryotes was carried out. Our fold-based search revealed structural and catalytic site similarity between bacterial phosphothreonine lyases and BLES03 (basophilic leukemia-expressed protein 03), a human protein with unknown function. Ligand induced conformational changes similar to bacterial phosphothreonine lyases, and movement of crucial arginines in the loop region to the catalytic pocket upon binding of phosphothreonine-containing peptides was seen during docking and molecular dynamics studies. Genome-wide search for BLES03 homologs using sensitive profile-based methods revealed their presence not only in eukaryotic classes such as chordata and fungi but also in bacterial and archaebacterial classes. The synteny of these archaebacterial BLES03-like proteins was remarkably similar to that of type IV lantibiotic synthetases which harbor LanL-like phosphothreonine lyase domains. Hence, context-based analysis reinforced our earlier sequence/structure-based prediction of phosphothreonine lyase catalytic function for BLES03. Our in silico analysis has revealed that BLES03-like proteins with previously unknown function are novel eukaryotic phosphothreonine lyases involved in biosynthesis of dehydro amino acids, whereas their bacterial and archaebacterial counterparts might be involved in biosynthesis of natural products similar to lantibiotics.

  17. Genome-wide evaluation of genetic diversity and linkage disequilibrium in winter and spring triticale (x Triticosecale Wittmack)

    PubMed Central

    2012-01-01

    Background Recent advances in genotyping with high-density markers nowadays enable genome-wide genomic analyses in crops. A detailed characterisation of the population structure and linkage disequilibrium (LD) is essential for the application of genomic approaches and consequently for knowledge-based breeding. In this study we used the triticale-specific DArT array to analyze population structure, genetic diversity, and LD in a worldwide set of 161 winter and spring triticale lines. Results The principal coordinate analysis revealed that the first principal coordinate divides the triticale population into two clusters according to their growth habit. The density distributions of the first ten principal coordinates revealed that several show a distribution indicative of population structure. In addition, we observed relatedness within growth habits which was higher among the spring types than among the winter types. The genome-wide analysis of polymorphic information content (PIC) showed that the PIC is variable among and along chromosomes and that especially the R genome of spring types possesses a reduced genetic diversity. We also found that several chromosomes showed regions of high genetic distance between the two growth habits, indicative of divergent selection. Regarding linkage disequilibrium, the A and B genomes showed a similar LD of 0.24 for closely linked markers and a decay within approximately 12 cM. LD in the R genome was lower with 0.19 and decayed within a shorter map distance of approximately 5 cM. The extent of LD was generally higher for the spring types compared to the winter types. In addition, we observed strong variability of LD along the chromosomes. Conclusions Our results confirm winter and spring growth habit are the major contributors to population structure in triticale, and a family structure exists in both growth types. The specific patterns of genetic diversity observed within these types, such as the low diversity on some rye

  18. Genome-wide linkage analysis for ocular and nasal anthropometric traits in a Mongolian population.

    PubMed

    Im, Sun-Wha; Kim, Hyun-Jin; Lee, Mi Kyeong; Yi, Jae-hyuk; Jargal, Ganchimeg; Sung, Joohon; Cho, Sung-il; Kim, Jong-Il

    2010-12-31

    Anthropometric traits for eyes and nose are complex quantitative traits influenced by genetic and environmental factors. To date, there have been few reports on the contribution of genetic influence to these traits in Asian populations. The aim of this study was to determine the genetic effect and quantitative trait locus (QTL) of seven traits eyes- and nose-related anthropometric measurements in an isolated Mongolian population. Frontal and lateral photographs were obtained from 1,014 individuals (434 males and 580 females) of Mongolian origin. A total of 349 short tandem repeat markers on 22 autosomes were genotyped for each individual. Heritability estimates of the seven ocular and nasal traits, adjusted for significant covariates, ranged from 0.48 to 0.90, providing evidence for a genetic influence. Variance-component linkage analyses revealed 10 suggestive linkage signals on 5q34 (LOD=3.2), 18q12.2 (LOD=2.7), 5q15 (LOD=2.0), 9q34.2 (LOD=1.9), 5q34 (LOD=1.9), 17q22 (LOD=1.9), 13q33.3 (LOD=2.7), 1q36.22 (LOD=1.9), 4q32.1 (LOD=2.1) and 15q22.31 (LOD=2.9). Our study provides the first evidence that genetics influences nasal and ocular traits in a Mongolian population. Additional collaborative efforts will further extend our understanding of the link between genetic factors and human anthropometric traits.

  19. Genome-wide linkage and association analysis of primary open-angle glaucoma endophenotypes in the Norfolk Island isolate.

    PubMed

    Matovinovic, Elizabeth; Kho, Pik Fang; Lea, Rodney A; Benton, Miles C; Eccles, David A; Haupt, Larisa M; Hewitt, Alex W; Sherwin, Justin C; Mackey, David A; Griffiths, Lyn R

    2017-01-01

    Primary open-angle glaucoma (POAG) refers to a group of heterogeneous diseases involving optic nerve damage. Two well-established risk factors for POAG are elevated intraocular pressure (IOP) and a thinner central corneal thickness (CCT). These endophenotypes exhibit a high degree of heritability across populations. Large-scale genome-wide association studies (GWASs) of outbred populations have robustly implicated several susceptibility gene variants for both IOP and CCT. Despite this progress, a substantial amount of genetic variance remains unexplained. Population-specific variants that might be rare in outbred populations may also influence POAG endophenotypes. The Norfolk Island population is a founder-effect genetic isolate that has been well characterized for POAG endophenotypes. This population is therefore a suitable candidate for mapping new variants that influence these complex traits. Three hundred and thirty participants from the Norfolk Island Eye Study (NIES) core pedigree provided DNA. Ocular measurements of CCT and IOP were also taken for analysis. Heritability analyses and genome-wide linkage analyses of short tandem repeats (STRs) were conducted using SOLAR. Pedigree-based GWASs of single-nucleotide polymorphisms (SNPs) were performed using the GenABEL software. CCT was the most heritable endophenotype in this cohort (h(2) = 0.77, p = 6×10(-6)), while IOP showed a heritability of 0.39 (p = 0.008). A genome-wide linkage analysis of these POAG phenotypes identified a maximum logarithm of the odds (LOD) score of 1.9 for CCT on chromosome 20 (p = 0.0016) and 1.3 for IOP on chromosome 15 (p = 0.0072). The GWAS results revealed a study-wise significant association for IOP at rs790357, which is located within DLG2 on chr11q14.1 (p = 1.02×10(-7)). DLG2 is involved in neuronal signaling and development, and while it has not previously been associated with IOP, it has been associated with myopia. An analysis of 12 known SNPs for IOP showed that rs12419342

  20. Genome-wide linkage scans for loci affecting total cholesterol, HDL-C, and triglycerides: the Family Blood Pressure Program.

    PubMed

    Bielinski, Suzette J; Tang, Weihong; Pankow, James S; Miller, Michael B; Mosley, Thomas H; Boerwinkle, Eric; Olshen, Richard A; Curb, J David; Jaquish, Cashell E; Rao, D C; Weder, Alan; Arnett, Donna K

    2006-10-01

    Atherosclerosis accounts for 75% of all deaths from cardiovascular disease and includes coronary heart disease (CHD), stroke, and other diseases of the arteries. More than half of all CHD is attributable to abnormalities in levels and metabolism of lipids. To locate genes that affect total cholesterol, high density lipoprotein cholesterol (HDL-C), and triglycerides, genome-wide linkage scans for quantitative trait loci were performed using variance components methods as implemented in SOLAR on a large diverse sample recruited as part of the Family Blood Pressure Program. Phenotype and genetic marker data were available for 9,299 subjects in 2,953 families for total cholesterol, 8,668 subjects in 2,736 families for HDL, and 7,760 subjects in 2,499 families for triglycerides. Mean lipid levels were adjusted for the effects of sex, age, age2, age-by-sex interaction, body mass index, smoking status, and field center. HDL-C and triglycerides were further adjusted for average total alcoholic drinks per week and estrogen use. Significant linkage was found for total cholesterol on chromosome 2 (LOD=3.1 at 43 cM) in Hispanics and for HDL-C on chromosome 3 (LOD=3.0 at 182 cM) and 12 (LOD=3.5 at 124 cM) in Asians. In addition, there were 13 regions that showed suggestive linkage (LOD >or= 2.0); 7 for total cholesterol, 4 for HDL, and 2 for triglycerides. The identification of these loci affecting lipid phenotypes and the apparent congruence with previous linkage results provides increased support that these regions contain genes influencing lipid levels.

  1. Linkage Disequilibrium and Genome-Wide Association Mapping in Tetraploid Wheat (Triticum turgidum L.)

    PubMed Central

    Laidò, Giovanni; Marone, Daniela; Russo, Maria A.; Colecchia, Salvatore A.; Mastrangelo, Anna M.; De Vita, Pasquale; Papa, Roberto

    2014-01-01

    Association mapping is a powerful tool for the identification of quantitative trait loci through the exploitation of the differential decay of linkage disequilibrium (LD) between marker loci and genes of interest in natural and domesticated populations. Using a sample of 230 tetraploid wheat lines (Triticum turgidum ssp), which included naked and hulled accessions, we analysed the pattern of LD considering 26 simple sequence repeats and 970 mostly mapped diversity array technology loci. In addition, to validate the potential for association mapping in durum wheat, we evaluated the same genotypes for plant height, heading date, protein content, and thousand-kernel weight. Molecular and phenotypic data were used to: (i) investigate the genetic and phenotypic diversity; (ii) study the dynamics of LD across the durum wheat genome, by investigating the patterns of LD decay; and (iii) test the potential of our panel to identify marker–trait associations through the analysis of four quantitative traits of major agronomic importance. Moreover, we compared and validated the association mapping results with outlier detection analysis based on population divergence. Overall, in tetraploid wheat, the pattern of LD is extremely population dependent and is related to the domestication and breeding history of durum wheat. Comparing our data with several other studies in wheat, we confirm the position of many major genes and quantitative trait loci for the traits considered. Finally, the analysis of the selection signature represents a very useful complement to validate marker–trait associations. PMID:24759998

  2. Linkage disequilibrium and genome-wide association mapping in tetraploid wheat (Triticum turgidum L.).

    PubMed

    Laidò, Giovanni; Marone, Daniela; Russo, Maria A; Colecchia, Salvatore A; Mastrangelo, Anna M; De Vita, Pasquale; Papa, Roberto

    2014-01-01

    Association mapping is a powerful tool for the identification of quantitative trait loci through the exploitation of the differential decay of linkage disequilibrium (LD) between marker loci and genes of interest in natural and domesticated populations. Using a sample of 230 tetraploid wheat lines (Triticum turgidum ssp), which included naked and hulled accessions, we analysed the pattern of LD considering 26 simple sequence repeats and 970 mostly mapped diversity array technology loci. In addition, to validate the potential for association mapping in durum wheat, we evaluated the same genotypes for plant height, heading date, protein content, and thousand-kernel weight. Molecular and phenotypic data were used to: (i) investigate the genetic and phenotypic diversity; (ii) study the dynamics of LD across the durum wheat genome, by investigating the patterns of LD decay; and (iii) test the potential of our panel to identify marker-trait associations through the analysis of four quantitative traits of major agronomic importance. Moreover, we compared and validated the association mapping results with outlier detection analysis based on population divergence. Overall, in tetraploid wheat, the pattern of LD is extremely population dependent and is related to the domestication and breeding history of durum wheat. Comparing our data with several other studies in wheat, we confirm the position of many major genes and quantitative trait loci for the traits considered. Finally, the analysis of the selection signature represents a very useful complement to validate marker-trait associations.

  3. Genome-wide linkage disequilibrium analysis in bread wheat and durum wheat.

    PubMed

    Somers, Daryl J; Banks, Travis; Depauw, Ron; Fox, Stephen; Clarke, John; Pozniak, Curtis; McCartney, Curt

    2007-06-01

    Bread wheat and durum wheat were examined for linkage disequilibrium (LD) using microsatellite markers distributed across the genome. The allele database consisted of 189 bread wheat accessions genotyped at 370 loci and 93 durum wheat accessions genotyped at 245 loci. A significance level of p < 0.001 was set for all comparisons. The bread and durum wheat collections showed that 47.9% and 14.0% of all locus pairs were in LD, respectively. LD was more prevalent between loci on the same chromosome compared with loci on independent chromosomes and was highest between adjacent loci. Only a small fraction (bread wheat, 0.9%; durum wheat, 3.2%) of the locus pairs in LD showed R2 values > 0.2. The LD between adjacent locus pairs extended (R2 > 0.2) approximately 2-3 cM, on average, but some regions of the bread and durum wheat genomes showed high levels of LD (R2 = 0.7 and 1.0, respectively) extending 41.2 and 25.5 cM, respectively. The wheat collections were clustered by similarity into subpopulations using unlinked microsatellite data and the software Structure. Analysis within subpopulations showed 14- to 16-fold fewer locus pairs in LD, higher R2 values for those pairs in LD, and LD extending further along the chromosome. The data suggest that LD mapping of wheat can be performed with simple sequence repeats to a resolution of <5 cM.

  4. Genome-wide linkage disequilibrium and past effective population size in three Korean cattle breeds.

    PubMed

    Sudrajad, P; Seo, D W; Choi, T J; Park, B H; Roh, S H; Jung, W Y; Lee, S S; Lee, J H; Kim, S; Lee, S H

    2017-02-01

    The routine collection and use of genomic data are useful for effectively managing breeding programs for endangered populations. Linkage disequilibrium (LD) using high-density DNA markers has been widely used to determine population structures and predict the genomic regions that are associated with economic traits in beef cattle. The extent of LD also provides information about historical events, including past effective population size (Ne ), and it allows inferences on the genetic diversity of breeds. The objective of this study was to estimate the LD and Ne in three Korean cattle breeds that are genetically similar but have different coat colors (Brown, Brindle and Jeju Black Hanwoo). Brindle and Jeju Black are endangered breeds with small populations, whereas Brown Hanwoo is the main breeding population in Korea. DNA samples from these cattle breeds were genotyped using the Illumina BovineSNP50 Bead Chip. We examined 13 cattle breeds, including European taurines, African taurines and indicines, and hybrids to compare their LD values. Brown Hanwoo consistently had the lowest mean LD compared to Jeju Black, Brindle and the other 13 cattle breeds (0.13, 0.19, 0.21 and 0.15-0.22 respectively). The high LD values of Brindle and Jeju Black contributed to small Ne values (53 and 60 respectively), which were distinct from that of Brown Hanwoo (531) for 11 generations ago. The differences in LD and Ne for each breed reflect the breeding strategy applied. The Ne for these endangered cattle breeds remain low; thus, effort is needed to bring them back to a sustainable tract. © 2016 Stichting International Foundation for Animal Genetics.

  5. SNP markers-based map construction and genome-wide linkage analysis in Brassica napus.

    PubMed

    Raman, Harsh; Dalton-Morgan, Jessica; Diffey, Simon; Raman, Rosy; Alamery, Salman; Edwards, David; Batley, Jacqueline

    2014-09-01

    An Illumina Infinium array comprising 5306 single nucleotide polymorphism (SNP) markers was used to genotype 175 individuals of a doubled haploid population derived from a cross between Skipton and Ag-Spectrum, two Australian cultivars of rapeseed (Brassica napus L.). A genetic linkage map based on 613 SNP and 228 non-SNP (DArT, SSR, SRAP and candidate gene markers) covering 2514.8 cM was constructed and further utilized to identify loci associated with flowering time and resistance to blackleg, a disease caused by the fungus Leptosphaeria maculans. Comparison between genetic map positions of SNP markers and the sequenced Brassica rapa (A) and Brassica oleracea (C) genome scaffolds showed several genomic rearrangements in the B. napus genome. A major locus controlling resistance to L. maculans was identified at both seedling and adult plant stages on chromosome A07. QTL analyses revealed that up to 40.2% of genetic variation for flowering time was accounted for by loci having quantitative effects. Comparative mapping showed Arabidopsis and Brassica flowering genes such as Phytochrome A/D, Flowering Locus C and agamous-Like MADS box gene AGL1 map within marker intervals associated with flowering time in a DH population from Skipton/Ag-Spectrum. Genomic regions associated with flowering time and resistance to L. maculans had several SNP markers mapped within 10 cM. Our results suggest that SNP markers will be suitable for various applications such as trait introgression, comparative mapping and high-resolution mapping of loci in B. napus. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  6. Ocular refraction: heritability and genome-wide search for eye morphometry traits in an isolated Sardinian population.

    PubMed

    Biino, Ginevra; Palmas, Maria Antonietta; Corona, Carla; Prodi, Dionigio; Fanciulli, Manuela; Sulis, Roberta; Serra, Antonina; Fossarello, Maurizio; Pirastu, Mario

    2005-02-01

    No genes influencing oculometric phenotypes have yet been identified, despite it being well known that eye morphometry is involved in refraction and that genetics may play an important role. We have therefore performed a heritability analysis and genome-wide search (GWS) of biometric ocular traits in an isolated Sardinian population, assessing the genetic contribution and identifying the associated genetic loci. A complete eye examination including refraction and ocular biometry measurements such as axial length (AL), anterior chamber depth (ACD) and corneal curvature (CC), was performed on 789 subjects. Heritability analysis was carried out by means of parent-offspring regression and variance component models. Univariate and bivariate linkage analysis was performed by using 654 microsatellite markers spanning the genome. CC showed a mean heritability of 57%. AL and ACD were found to have significantly different variances (P<0.01) in males and females, so that heritability was calculated separately for each sex. AL had an estimated heritability in females of 31% and in males of 60%, whereas ACD had an estimated heritability of 47% in females and of 44% in males. In the GWS, the most suggestive evidence of linkage was identified on chromosome 2 for AL (LOD 2.64), on chromosome 1 for ACD (LOD 2.32) and on chromosomes 7, 2 and 3 for CC (LOD 2.50, 2.44 and 2.34, respectively). High heritability of eye morphometry traits was thus revealed. The identified loci are the first linkage signals available in ocular biometry. Notably, the observed significant differences in parental transmission deserve further study.

  7. Genome-wide linkage scan of epilepsy-related photoparoxysmal electroencephalographic response: evidence for linkage on chromosomes 7q32 and 16p13.

    PubMed

    Pinto, Dalila; Westland, Birgit; de Haan, Gerrit-Jan; Rudolf, Gabrielle; da Silva, Berta Martins; Hirsch, Edouard; Lindhout, Dick; Trenité, Dorothée G A Kasteleijn-Nolst; Koeleman, Bobby P C

    2005-01-01

    Photoparoxysmal response (PPR) is an abnormal visual sensitivity of the brain in reaction to intermittent photic stimulation. It is an epilepsy-related electroencephalographic trait with high prevalence in idiopathic epilepsies, especially in common idiopathic generalized epilepsies (IGEs), such as childhood absence epilepsy and juvenile myoclonic epilepsy. This degree of co-morbidity suggests that PPR may be involved in the predisposition to IGE. The identification of genes for PPR would, therefore, aid the dissection of the genetic basis of IGE. Sixteen PPR-multiplex families were collected to conduct a genome-wide linkage scan using broad (all PPR types) and narrow (exclusion of PPR types I and II and the occipital epilepsy cases) models of affectedness for PPR. We found an empirical genome-wide significance for parametric (HLOD) and non-parametric (NPL) linkage (Pgw(HLOD)=0.004 and Pgw(NPL)=0.01) for two respective chromosomal regions, 7q32 at D7S1804 (HLOD=3.47 with alpha=1, P(NPL)=3.39x10(-5)) and 16p13 at D16S3395 (HLOD=2.44 with alpha=1, P(NPL)=7.91x10(-5)). These two genomic regions contain genes that are important for the neuromodulation of cortical dynamics and may represent good targets for candidate-gene studies. Our study identified two susceptibility loci for PPR, which may be related to the underlying myoclonic epilepsy phenotype present in the families studied.

  8. Genome-wide linkage scan for maximum and length-dependent knee muscle strength in young men: significant evidence for linkage at chromosome 14q24.3.

    PubMed

    De Mars, G; Windelinckx, A; Huygens, W; Peeters, M W; Beunen, G P; Aerssens, J; Vlietinck, R; Thomis, M A I

    2008-05-01

    Maintenance of high muscular fitness is positively related to bone health, functionality in daily life and increasing insulin sensitivity, and negatively related to falls and fractures, morbidity and mortality. Heritability of muscle strength phenotypes ranges between 31% and 95%, but little is known about the identity of the genes underlying this complex trait. As a first attempt, this genome-wide linkage study aimed to identify chromosomal regions linked to muscle and bone cross-sectional area, isometric knee flexion and extension torque, and torque-length relationship for knee flexors and extensors. In total, 283 informative male siblings (17-36 years old), belonging to 105 families, were used to conduct a genome-wide SNP-based multipoint linkage analysis. The strongest evidence for linkage was found for the torque-length relationship of the knee flexors at 14q24.3 (LOD = 4.09; p<10(-5)). Suggestive evidence for linkage was found at 14q32.2 (LOD = 3.00; P = 0.005) for muscle and bone cross-sectional area, at 2p24.2 (LOD = 2.57; p = 0.01) for isometric knee torque at 30 degrees flexion, at 1q21.3, 2p23.3 and 18q11.2 (LOD = 2.33, 2.69 and 2.21; p<10(-4) for all) for the torque-length relationship of the knee extensors and at 18p11.31 (LOD = 2.39; p = 0.0004) for muscle-mass adjusted isometric knee extension torque. We conclude that many small contributing genes rather than a few important genes are involved in causing variation in different underlying phenotypes of muscle strength. Furthermore, some overlap in promising genomic regions were identified among different strength phenotypes.

  9. STAMS: STRING-assisted module search for genome wide association studies and application to autism

    PubMed Central

    Hillenmeyer, Sara; Davis, Lea K.; Gamazon, Eric R.; Cook, Edwin H.; Cox, Nancy J.; Altman, Russ B.

    2016-01-01

    Motivation: Analyzing genome wide association data in the context of biological pathways helps us understand how genetic variation influences phenotype and increases power to find associations. However, the utility of pathway-based analysis tools is hampered by undercuration and reliance on a distribution of signal across all of the genes in a pathway. Methods that combine genome wide association results with genetic networks to infer the key phenotype-modulating subnetworks combat these issues, but have primarily been limited to network definitions with yes/no labels for gene-gene interactions. A recent method (EW_dmGWAS) incorporates a biological network with weighted edge probability by requiring a secondary phenotype-specific expression dataset. In this article, we combine an algorithm for weighted-edge module searching and a probabilistic interaction network in order to develop a method, STAMS, for recovering modules of genes with strong associations to the phenotype and probable biologic coherence. Our method builds on EW_dmGWAS but does not require a secondary expression dataset and performs better in six test cases. Results: We show that our algorithm improves over EW_dmGWAS and standard gene-based analysis by measuring precision and recall of each method on separately identified associations. In the Wellcome Trust Rheumatoid Arthritis study, STAMS-identified modules were more enriched for separately identified associations than EW_dmGWAS (STAMS P-value 3.0 × 10−4; EW_dmGWAS- P-value = 0.8). We demonstrate that the area under the Precision-Recall curve is 5.9 times higher with STAMS than EW_dmGWAS run on the Wellcome Trust Type 1 Diabetes data. Availability and Implementation: STAMS is implemented as an R package and is freely available at https://simtk.org/projects/stams. Contact: rbaltman@stanford.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27542772

  10. Genome-wide distribution of genetic diversity and linkage disequilibrium in a mass-selected population of maritime pine

    PubMed Central

    2014-01-01

    Background The accessibility of high-throughput genotyping technologies has contributed greatly to the development of genomic resources in non-model organisms. High-density genotyping arrays have only recently been developed for some economically important species such as conifers. The potential for using genomic technologies in association mapping and breeding depends largely on the genome wide patterns of diversity and linkage disequilibrium in current breeding populations. This study aims to deepen our knowledge regarding these issues in maritime pine, the first species used for reforestation in south western Europe. Results Using a new map merging algorithm, we first established a 1,712 cM composite linkage map (comprising 1,838 SNP markers in 12 linkage groups) by bringing together three already available genetic maps. Using rigorous statistical testing based on kernel density estimation and resampling we identified cold and hot spots of recombination. In parallel, 186 unrelated trees of a mass-selected population were genotyped using a 12k-SNP array. A total of 2,600 informative SNPs allowed to describe historical recombination, genetic diversity and genetic structure of this recently domesticated breeding pool that forms the basis of much of the current and future breeding of this species. We observe very low levels of population genetic structure and find no evidence that artificial selection has caused a reduction in genetic diversity. By combining these two pieces of information, we provided the map position of 1,671 SNPs corresponding to 1,192 different loci. This made it possible to analyze the spatial pattern of genetic diversity (H e ) and long distance linkage disequilibrium (LD) along the chromosomes. We found no particular pattern in the empirical variogram of H e across the 12 linkage groups and, as expected for an outcrossing species with large effective population size, we observed an almost complete lack of long distance LD. Conclusions These

  11. Population genomic structure and linkage disequilibrium analysis of South African goat breeds using genome-wide SNP data.

    PubMed

    Mdladla, K; Dzomba, E F; Huson, H J; Muchadeyi, F C

    2016-08-01

    The sustainability of goat farming in marginal areas of southern Africa depends on local breeds that are adapted to specific agro-ecological conditions. Unimproved non-descript goats are the main genetic resources used for the development of commercial meat-type breeds of South Africa. Little is known about genetic diversity and the genetics of adaptation of these indigenous goat populations. This study investigated the genetic diversity, population structure and breed relations, linkage disequilibrium, effective population size and persistence of gametic phase in goat populations of South Africa. Three locally developed meat-type breeds of the Boer (n = 33), Savanna (n = 31), Kalahari Red (n = 40), a feral breed of Tankwa (n = 25) and unimproved non-descript village ecotypes (n = 110) from four goat-producing provinces of the Eastern Cape, KwaZulu-Natal, Limpopo and North West were assessed using the Illumina Goat 50K SNP Bead Chip assay. The proportion of SNPs with minor allele frequencies >0.05 ranged from 84.22% in the Tankwa to 97.58% in the Xhosa ecotype, with a mean of 0.32 ± 0.13 across populations. Principal components analysis, admixture and pairwise FST identified Tankwa as a genetically distinct population and supported clustering of the populations according to their historical origins. Genome-wide FST identified 101 markers potentially under positive selection in the Tankwa. Average linkage disequilibrium was highest in the Tankwa (r(2)  = 0.25 ± 0.26) and lowest in the village ecotypes (r(2) range = 0.09 ± 0.12 to 0.11 ± 0.14). We observed an effective population size of <150 for all populations 13 generations ago. The estimated correlations for all breed pairs were lower than 0.80 at marker distances >100 kb with the exception of those in Savanna and Tswana populations. This study highlights the high level of genetic diversity in South African indigenous goats as well as the utility of the genome-wide SNP marker panels in

  12. Genome-wide linkage scan for loci of musical aptitude in Finnish families: evidence for a major locus at 4q22

    PubMed Central

    Pulli, K; Karma, K; Norio, R; Sistonen, P; Göring, H H H; Järvelä, I

    2008-01-01

    Background: Music perception and performance are comprehensive human cognitive functions and thus provide an excellent model system for studying human behaviour and brain function. However, the molecules involved in mediating music perception and performance are so far uncharacterised. Objective: To unravel the biological background of music perception, using molecular and statistical genetic approaches. Methods: 15 Finnish multigenerational families (with a total of 234 family members) were recruited via a nationwide search. The phenotype of all family members was determined using three tests used in defining musical aptitude: a test for auditory structuring ability (Karma Music test; KMT) commonly used in Finland, and the Seashore pitch and time discrimination subtests (SP and ST respectively) used internationally. We calculated heritabilities and performed a genome-wide variance components-based linkage scan using genotype data for 1113 microsatellite markers. Results: The heritability estimates were 42% for KMT, 57% for SP, 21% for ST and 48% for the combined music test scores. Significant evidence of linkage was obtained on chromosome 4q22 (LOD 3.33) and suggestive evidence of linkage at 8q13-21 (LOD 2.29) with the combined music test scores, using variance component linkage analyses. The major contribution of the 4q22 locus was obtained for the KMT (LOD 2.91). Interestingly, a positive LOD score of 1.69 was shown at 18q, a region previously linked to dyslexia (DYX6) using combined music test scores. Conclusion: Our results show that there is a genetic contribution to musical aptitude that is likely to be regulated by several predisposing genes or variants. PMID:18424507

  13. Genome-wide linkage scan for loci of musical aptitude in Finnish families: evidence for a major locus at 4q22.

    PubMed

    Pulli, K; Karma, K; Norio, R; Sistonen, P; Göring, H H H; Järvelä, I

    2008-07-01

    Music perception and performance are comprehensive human cognitive functions and thus provide an excellent model system for studying human behaviour and brain function. However, the molecules involved in mediating music perception and performance are so far uncharacterised. To unravel the biological background of music perception, using molecular and statistical genetic approaches. 15 Finnish multigenerational families (with a total of 234 family members) were recruited via a nationwide search. The phenotype of all family members was determined using three tests used in defining musical aptitude: a test for auditory structuring ability (Karma Music test; KMT) commonly used in Finland, and the Seashore pitch and time discrimination subtests (SP and ST respectively) used internationally. We calculated heritabilities and performed a genome-wide variance components-based linkage scan using genotype data for 1113 microsatellite markers. The heritability estimates were 42% for KMT, 57% for SP, 21% for ST and 48% for the combined music test scores. Significant evidence of linkage was obtained on chromosome 4q22 (LOD 3.33) and suggestive evidence of linkage at 8q13-21 (LOD 2.29) with the combined music test scores, using variance component linkage analyses. The major contribution of the 4q22 locus was obtained for the KMT (LOD 2.91). Interestingly, a positive LOD score of 1.69 was shown at 18q, a region previously linked to dyslexia (DYX6) using combined music test scores. Our results show that there is a genetic contribution to musical aptitude that is likely to be regulated by several predisposing genes or variants.

  14. Identifying Loci for the Overlap between Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder Using a Genome-Wide QTL Linkage Approach

    ERIC Educational Resources Information Center

    Nijmeijer, Judith S.; Arias-Vasquez, Alejandro; Rommelse, Nanda N. J.; Altink, Marieke E.; Anney, Richard J. L.; Asherson, Philip; Banaschewski, Tobias; Buschgens, Cathelijne J. M.; Fliers, Ellen A.; Gill, Michael; Minderaa, Ruud B.; Poustka, Luise; Sergeant, Joseph A.; Buitelaar, Jan K.; Franke, Barbara; Ebstein, Richard P.; Miranda, Ana; Mulas, Fernando; Oades, Robert D.; Roeyers, Herbert; Rothenberger, Aribert; Sonuga-Barke, Edmund J. S.; Steinhausen, Hans-Christoph; Faraone, Stephen V.; Hartman, Catharina A.; Hoekstra, Pieter J.

    2010-01-01

    Objective: The genetic basis for autism spectrum disorder (ASD) symptoms in children with attention-deficit/hyperactivity disorder (ADHD) was addressed using a genome-wide linkage approach. Method: Participants of the International Multi-Center ADHD Genetics study comprising 1,143 probands with ADHD and 1,453 siblings were analyzed. The total and…

  15. Identifying Loci for the Overlap between Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder Using a Genome-Wide QTL Linkage Approach

    ERIC Educational Resources Information Center

    Nijmeijer, Judith S.; Arias-Vasquez, Alejandro; Rommelse, Nanda N. J.; Altink, Marieke E.; Anney, Richard J. L.; Asherson, Philip; Banaschewski, Tobias; Buschgens, Cathelijne J. M.; Fliers, Ellen A.; Gill, Michael; Minderaa, Ruud B.; Poustka, Luise; Sergeant, Joseph A.; Buitelaar, Jan K.; Franke, Barbara; Ebstein, Richard P.; Miranda, Ana; Mulas, Fernando; Oades, Robert D.; Roeyers, Herbert; Rothenberger, Aribert; Sonuga-Barke, Edmund J. S.; Steinhausen, Hans-Christoph; Faraone, Stephen V.; Hartman, Catharina A.; Hoekstra, Pieter J.

    2010-01-01

    Objective: The genetic basis for autism spectrum disorder (ASD) symptoms in children with attention-deficit/hyperactivity disorder (ADHD) was addressed using a genome-wide linkage approach. Method: Participants of the International Multi-Center ADHD Genetics study comprising 1,143 probands with ADHD and 1,453 siblings were analyzed. The total and…

  16. Single nucleotide polymorphisms generated by genotyping by sequencing to characterize genome-wide diversity, linkage disequilibrium, and selective sweeps in cultivated watermelon

    USDA-ARS?s Scientific Manuscript database

    Large datasets containing single nucleotide polymorphisms (SNPs) are used to analyze genome-wide diversity in a robust collection of cultivars from representative accessions, across the world. The extent of linkage disequilibrium (LD) within a population determines the number of markers required fo...

  17. A genome-wide search for genes predisposing to familial psoriasis by using a stratification approach.

    PubMed

    Samuelsson, L; Enlund, F; Torinsson, A; Yhr, M; Inerot, A; Enerbäck, C; Wahlström, J; Swanbeck, G; Martinsson, T

    1999-12-01

    We have performed a genome scan, using markers spaced by 10 cM, in the search for psoriasis-susceptibility loci. The family material of 134 affected sibling pairs was ascertained on the basis of a population genetic study in which 65% of the probands had two healthy parents. Genotyping results were analyzed for non-random excessive allele-sharing between sib pairs by using GENEHUNTER ver 1.1. A stratification approach was applied to increase the homogeneity of the material by means of an operational definition of joint complaints among affected individuals. Significant linkage to the human leukocyte antigen region on chromosome 6p in a cohort including 42 families without joint complaints (nonparametric linkage score of 2.83, P=0.002) strongly supported the validity of this operational definition as it replicated results from an earlier linkage report with similar stratification criteria. New candidate regions on chromosomes 3 and 15 were identified. The highest non-parametric linkage values in this study, 2.96 (P=0.0017) and 2.89 (P=0.0020), were reached on chromosome 15 in a subgroup with joint complaints and on chromosome 3 in a subgroup without joint complaints. In addition, confirmation of previously reported loci was established on chromosomes 4q, 6p, and 17q. This study indicates that distinct disease loci might be involved in psoriasis etiology for various phenotypes.

  18. Genetic epidemiology and genome-wide linkage analysis of carotid artery ultrasound traits in multigenerational African ancestry families.

    PubMed

    Kuipers, Allison L; Kammerer, Candace M; Miljkovic, Iva; Woodard, Genevieve A; Bunker, Clareann H; Patrick, Alan L; Wheeler, Victor W; Newman, Anne B; Zmuda, Joseph M

    2013-11-01

    Intima-media thickness, adventitial diameter and lumen diameter are indicators of cardiovascular disease risk. The influence of genetic factors on these measures in African ancestry populations is not well defined. Therefore, we estimated heritability and performed genome-wide linkage analysis of carotid ultrasound traits in 7 multigenerational families of African ancestry. A total of 395 individuals (7 pedigrees; mean family size = 56; 2392 relative pairs) aged ≥18 years had a common carotid artery ultrasound scan. Statistical analyses were conducted using pedigree-based maximum likelihood methods. Significant covariates included age, sex, body mass index or height and waist, and systolic blood pressure. Residual heritabilities ranged from 0.35 ± 0.10 to 0.64 ± 0.12 (P < 0.0001). We identified a novel quantitative trait locus for adventitial and lumen diameters on chromosome 11 (max LOD = 4.09, 133 cm). Further fine mapping of this region may identify specific mutations predisposing to subclinical vascular disease among African ancestry individuals. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  19. A genome-wide set of SNPs detects population substructure and long range linkage disequilibrium in wild sheep.

    PubMed

    Miller, J M; Poissant, J; Kijas, J W; Coltman, D W

    2011-03-01

    The development of genomic resources for wild species is still in its infancy. However, cross-species utilization of technologies developed for their domestic counterparts has the potential to unlock the genomes of organisms that currently lack genomic resources. Here, we apply the OvineSNP50 BeadChip, developed for domestic sheep, to two related wild ungulate species: the bighorn sheep (Ovis canadensis) and the thinhorn sheep (Ovis dalli). Over 95% of the domestic sheep markers were successfully genotyped in a sample of fifty-two bighorn sheep while over 90% were genotyped in two thinhorn sheep. Pooling the results from both species identified 868 single-nucleotide polymorphisms (SNPs), 570 were detected in bighorn sheep, while 330 SNPs were identified in thinhorn sheep. The total panel of SNPs was able to discriminate between the two species, assign population of origin for bighorn sheep and detect known relationship classes within one population of bighorn sheep. Using an informative subset of these SNPs (n=308), we examined the extent of genome-wide linkage disequilibrium (LD) within one population of bighorn sheep and found that high levels of LD persist over 4 Mb.

  20. Tagging SNP-set selection with maximum information based on linkage disequilibrium structure in genome-wide association studies.

    PubMed

    Wang, Shudong; He, Sicheng; Yuan, Fayou; Zhu, Xinjie

    2017-07-15

    Effective tagging single-nucleotide polymorphism (SNP)-set selection is crucial to SNP-set analysis in genome-wide association studies (GWAS). Most of the existing tagging SNP-set selection methods cannot make full use of the information hidden in common or rare variants associated diseases. It is noticed that some SNPs have overlapping genetic information owing to linkage disequilibrium (LD) structure between SNPs. Therefore, when testing the association between SNPs and disease susceptibility, it is sufficient to elect the representative SNPs (called tag SNP-set or tagSNP-set) with maximum information. It is proposed a new tagSNP-set selection method based on LD information between SNPs, namely TagSNP-Set with Maximum Information. Compared with classical SNP-set analytical method, our method not only has higher power, but also can minimize the number of selected tagSNPs and maximize the information provided by selected tagSNPs with less genotyping cost and lower time complexity. hesicheng12@163.com. Supplementary data are available at Bioinformatics online.

  1. Genome-wide survey of Arabidopsis natural variation in downy mildew resistance using combined association and linkage mapping

    PubMed Central

    Nemri, Adnane; Atwell, Susanna; Tarone, Aaron M.; Huang, Yu S.; Zhao, Keyan; Studholme, David J.; Nordborg, Magnus; Jones, Jonathan D. G.

    2010-01-01

    The model plant Arabidopsis thaliana exhibits extensive natural variation in resistance to parasites. Immunity is often conferred by resistance (R) genes that permit recognition of specific races of a disease. The number of such R genes and their distribution are poorly understood. In this study, we investigated the basis for resistance to the downy mildew agent Hyaloperonospora arabidopsidis ex parasitica (Hpa) in a global sample of A. thaliana. We implemented a combined genome-wide mapping of resistance using populations of recombinant inbred lines and a collection of wild A. thaliana accessions. We tested the interaction between 96 host genotypes collected worldwide and five strains of Hpa. Then, a fraction of the species-wide resistance was genetically dissected using six recently constructed populations of recombinant inbred lines. We found that resistance is usually governed by single dominant R genes that are concentrated in four genomic regions only. We show that association genetics of resistance to diseases such as downy mildew enables increased mapping resolution from quantitative trait loci interval to candidate gene level. Association patterns in quantitative trait loci intervals indicate that the pool of A. thaliana resistance sources against the tested Hpa isolates may be predominantly confined to six RPP (Resistance to Hpa) loci isolated in previous studies. Our results suggest that combining association and linkage mapping could accelerate resistance gene discovery in plants. PMID:20479233

  2. Genome-wide linkage analysis for severe obesity in french caucasians finds significant susceptibility locus on chromosome 19q.

    PubMed

    Bell, Christopher G; Benzinou, Michael; Siddiq, Afshan; Lecoeur, Cécile; Dina, Christian; Lemainque, Arnaud; Clément, Karine; Basdevant, Arnaud; Guy-Grand, Bernard; Mein, Charles A; Meyre, David; Froguel, Philippe

    2004-07-01

    To ascertain whether distinct chromosomal loci existed that were linked to severe obesity, as well as to utilize the increased heritability of this excessive phenotype, we performed a genome-wide scan in severely obese French Caucasians. The 109 selected pedigrees, totaling 447 individuals, required both the proband and a sibling to be severely obese (BMI >or=35 kg/m(2)), and 84.8% of the nuclear families possessed >or=1 morbidly obese sibling (BMI >or=40). Severe and morbid obesity are still relatively rare in France, with rates of 2.5 and 0.6%, respectively. The initial genome scan consisted of 395 evenly spaced microsatellite markers. Six regions were found to have suggestive linkage on 4q, 6cen-q, 17q, and 19q for a BMI >or=35 phenotypic subset, and 5q and 10q for an inclusive BMI >or=27 group. The highest peak on chromosome 19q (logarithm of odds [LOD] = 3.59) was significant by genome scan simulation testing (P = 0.042). These regions then underwent second-stage mapping with an additional set of 42 markers. BMI >or=35 analysis defined regions on 17q23.3-25.1 and 19q13.33-13.43 with an maximum likelihood score LOD of 3.16 and 3.21, respectively. Subsequent pooled data analysis with an additional previous population of 66 BMI >or=35 sib-pairs led to a significant LOD score of 3.8 at the 19q locus (empirical P = 0.023). For more moderate obesity and overweight susceptibility loci, BMI >or=27 analysis confirmed suggestive linkage to chromosome regions 5q14.3-q21.3 (LOD = 2.68) and 10q24.32-26.2 (LOD = 2.47). Plausible positional candidate genes include NR1H2 and TULP2.

  3. Population structure and linkage disequilibrium in oat (Avena sativa L.): implications for genome-wide association studies.

    PubMed

    Newell, M A; Cook, D; Tinker, N A; Jannink, J-L

    2011-02-01

    The level of population structure and the extent of linkage disequilibrium (LD) can have large impacts on the power, resolution, and design of genome-wide association studies (GWAS) in plants. Until recently, the topics of LD and population structure have not been explored in oat due to the lack of a high-throughput, high-density marker system. The objectives of this research were to survey the level of population structure and the extent of LD in oat germplasm and determine their implications for GWAS. In total, 1,205 lines and 402 diversity array technology (DArT) markers were used to explore population structure. Principal component analysis and model-based cluster analysis of these data indicated that, for the lines used in this study, relatively weak population structure exists. To explore LD decay, map distances of 2,225 linked DArT marker pairs were compared with LD (estimated as r²). Results showed that LD between linked markers decayed rapidly to r² = 0.2 for marker pairs with a map distance of 1.0 centi-Morgan (cM). For GWAS, we suggest a minimum of one marker every cM, but higher densities of markers should increase marker-QTL association and therefore detection power. Additionally, it was found that LD was relatively consistent across the majority of germplasm clusters. These findings suggest that GWAS in oat can include germplasm with diverse origins and backgrounds. The results from this research demonstrate the feasibility of GWAS and related analyses in oat.

  4. Bayesian Variable Selection in Searching for Additive and Dominant Effects in Genome-Wide Data

    PubMed Central

    Peltola, Tomi; Marttinen, Pekka; Jula, Antti; Salomaa, Veikko; Perola, Markus; Vehtari, Aki

    2012-01-01

    Although complex diseases and traits are thought to have multifactorial genetic basis, the common methods in genome-wide association analyses test each variant for association independent of the others. This computational simplification may lead to reduced power to identify variants with small effect sizes and requires correcting for multiple hypothesis tests with complex relationships. However, advances in computational methods and increase in computational resources are enabling the computation of models that adhere more closely to the theory of multifactorial inheritance. Here, a Bayesian variable selection and model averaging approach is formulated for searching for additive and dominant genetic effects. The approach considers simultaneously all available variants for inclusion as predictors in a linear genotype-phenotype mapping and averages over the uncertainty in the variable selection. This leads to naturally interpretable summary quantities on the significances of the variants and their contribution to the genetic basis of the studied trait. We first characterize the behavior of the approach in simulations. The results indicate a gain in the causal variant identification performance when additive and dominant variation are simulated, with a negligible loss of power in purely additive case. An application to the analysis of high- and low-density lipoprotein cholesterol levels in a dataset of 3895 Finns is then presented, demonstrating the feasibility of the approach at the current scale of single-nucleotide polymorphism data. We describe a Markov chain Monte Carlo algorithm for the computation and give suggestions on the specification of prior parameters using commonly available prior information. An open-source software implementing the method is available at http://www.lce.hut.fi/research/mm/bmagwa/ and https://github.com/to-mi/. PMID:22235263

  5. Genome-wide linkage of obstructive sleep apnoea and high-density lipoprotein cholesterol in a Filipino family: bivariate linkage analysis of obstructive sleep apnoea.

    PubMed

    Relf, Bronwyn L; Larkin, Emma K; De Torres, Carina; Baur, Louise A; Christodoulou, John; Waters, Karen A

    2010-06-01

    Increasing evidence supports an association between obstructive sleep apnoea (OSA) and metabolic syndrome (MeS) in both children and adults, suggesting a genetic component. However, the genetic relationship between the diseases remains unclear. We performed a bivariate linkage scan on a single Filipino family with a high prevalence of OSA and MeS to explore the genetic pathways underlying these diseases. A large rural family (n = 50, 50% adults) underwent a 10-cM genome-wide scan. Fasting blood was used to measure insulin, triglycerides, total cholesterol and high density lipoprotein (HDL) cholesterol. Attended overnight polysomnography was used to quantify the respiratory disturbance index (RDI), a measure of sleep apnoea. Body mass index z-scores and insulin resistance scores were calculated. Bivariate multipoint linkage analyses were performed on RDI and MeS components. OSA prevalence was 46% (n = 23; nine adults, 14 children) in our participants. MeS phenotype was present in 40% of adults (n = 10) and 48% of children (n = 12). Linkage peaks with a logarithm of odds (LOD) score >3 were demonstrated on chromosome 19q13.4 (LOD = 3.04) for the trait pair RDI and HDL cholesterol. Candidate genes identified in this region include the killer cell immunoglobulin-like receptor genes. These genes are associated with modulating inflammatory responses in reaction to cellular stress and initiation of atherosclerotic plaque formation. We have identified a novel locus for genetic links between RDI and lipid factors associated with MeS in a chromosomal region containing genes associated with inflammatory responses.

  6. Genome wide search for variation associated with micronutrient density of developing rice grains

    USDA-ARS?s Scientific Manuscript database

    "Omic" tools are rapidly being employed to delineate the biological framework controlling phenotypes of interest in crop species. An advanced understanding of the genetic basis for quantitative trait variation has been made possible through genome wide association studies (GWAS) that make use of gen...

  7. Patterns of linkage disequilibrium in different populations: implications and opportunities for lipid-associated loci identified from genome-wide association studies.

    PubMed

    Teo, Yik-Ying; Sim, Xueling

    2010-04-01

    Genome-wide association studies across numerous populations have uncovered a remarkable number of loci implicated with lipid-related traits. The association signals at a number of these loci have been successfully replicated across multiple populations, but a fraction failed to be reproduced when tested in other populations. The present review examines the patterns of linkage disequilibrium at these lipid-associated loci and the implications to replication studies, meta-analyses and fine-mapping efforts across multiple populations. The extent of linkage disequilibrium has been well established to differ across populations, particularly between African and non-African groups. A novel strategy has been developed for assessing interpopulation variations in regional patterns of linkage disequilibrium. This approach has been applied to the genomes of populations in public databases, identifying regions where linkage disequilibrium is considerably different, some of which exist in regions associated with phenotypic variation. It has been shown that such diversity in linkage disequilibrium can challenge replication studies and meta-analyses while benefiting the pursuit for the functional variants in fine-mapping studies. The next phases in genome-wide studies aim to reproduce the emerging association signals across different populations and to identify the functional variants directly responsible for these signals. Recent publications are beginning to yield valuable insights into the unique challenges and opportunities presented by both consistent and varying patterns of linkage disequilibrium in these follow-up phases.

  8. Five blood pressure loci identified by an updated genome-wide linkage scan: meta-analysis of the Family Blood Pressure Program.

    PubMed

    Simino, Jeannette; Shi, Gang; Kume, Rezart; Schwander, Karen; Province, Michael A; Gu, C Charles; Kardia, Sharon; Chakravarti, Aravinda; Ehret, Georg; Olshen, Richard A; Turner, Stephen T; Ho, Low-Tone; Zhu, Xiaofeng; Jaquish, Cashell; Paltoo, Dina; Cooper, Richard S; Weder, Alan; Curb, J David; Boerwinkle, Eric; Hunt, Steven C; Rao, Dabeeru C

    2011-03-01

    A preliminary genome-wide linkage analysis of blood pressure in the Family Blood Pressure Program (FBPP) was reported previously. We harnessed the power and ethnic diversity of the final pooled FBPP dataset to identify novel loci for blood pressure thereby enhancing localization of genes containing less common variants with large effects on blood pressure levels and hypertension. We performed one overall and 4 race-specific meta-analyses of genome-wide blood pressure linkage scans using data on 4,226 African-American, 2,154 Asian, 4,229 Caucasian, and 2,435 Mexican-American participants (total N = 13,044). Variance components models were fit to measured (raw) blood pressure levels and two types of antihypertensive medication adjusted blood pressure phenotypes within each of 10 subgroups defined by race and network. A modified Fisher's method was used to combine the P values for each linkage marker across the 10 subgroups. Five quantitative trait loci (QTLs) were detected on chromosomes 6p22.3, 8q23.1, 20q13.12, 21q21.1, and 21q21.3 based on significant linkage evidence (defined by logarithm of odds (lod) score ≥3) in at least one meta-analysis and lod scores ≥1 in at least 2 subgroups defined by network and race. The chromosome 8q23.1 locus was supported by Asian-, Caucasian-, and Mexican-American-specific meta-analyses. The new QTLs reported justify new candidate gene studies. They may help support results from genome-wide association studies (GWAS) that fall in these QTL regions but fail to achieve the genome-wide significance.

  9. Genome-wide SNP-Based Linkage Scan Identifies a Locus on 8q24 for an Age-Related Hearing Impairment Trait

    PubMed Central

    Huyghe, Jeroen R.; Van Laer, Lut; Hendrickx, Jan-Jaap; Fransen, Erik; Demeester, Kelly; Topsakal, Vedat; Kunst, Sylvia; Manninen, Minna; Jensen, Mona; Bonaconsa, Amanda; Mazzoli, Manuela; Baur, Manuela; Hannula, Samuli; Mäki-Torkko, Elina; Espeso, Angeles; Van Eyken, Els; Flaquer, Antonia; Becker, Christian; Stephens, Dafydd; Sorri, Martti; Orzan, Eva; Bille, Michael; Parving, Agnete; Pyykkö, Ilmari; Cremers, Cor W.R.J.; Kremer, Hannie; Van de Heyning, Paul H.; Wienker, Thomas F.; Nürnberg, Peter; Pfister, Markus; Van Camp, Guy

    2008-01-01

    Age-related hearing impairment (ARHI), or presbycusis, is a very common multifactorial disorder. Despite the knowledge that genetics play an important role in the etiology of human ARHI as revealed by heritability studies, to date, its precise genetic determinants remain elusive. Here we report the results of a cross-sectional family-based genetic study employing audiometric data. By using principal component analysis, we were able to reduce the dimensionality of this multivariate phenotype while capturing most of the variation and retaining biologically important features of the audiograms. We conducted a genome-wide association as well as a linkage scan with high-density SNP microarrays. Because of the presence of genetic population substructure, association testing was stratified after which evidence was combined by meta-analysis. No association signals reaching genome-wide significance were detected. Linkage analysis identified a linkage peak on 8q24.13-q24.22 for a trait correlated to audiogram shape. The signal reached genome-wide significance, as assessed by simulations. This finding represents the first locus for an ARHI trait. PMID:18760390

  10. Genome-wide SNP-based linkage scan identifies a locus on 8q24 for an age-related hearing impairment trait.

    PubMed

    Huyghe, Jeroen R; Van Laer, Lut; Hendrickx, Jan-Jaap; Fransen, Erik; Demeester, Kelly; Topsakal, Vedat; Kunst, Sylvia; Manninen, Minna; Jensen, Mona; Bonaconsa, Amanda; Mazzoli, Manuela; Baur, Manuela; Hannula, Samuli; Mäki-Torkko, Elina; Espeso, Angeles; Van Eyken, Els; Flaquer, Antonia; Becker, Christian; Stephens, Dafydd; Sorri, Martti; Orzan, Eva; Bille, Michael; Parving, Agnete; Pyykkö, Ilmari; Cremers, Cor W R J; Kremer, Hannie; Van de Heyning, Paul H; Wienker, Thomas F; Nürnberg, Peter; Pfister, Markus; Van Camp, Guy

    2008-09-01

    Age-related hearing impairment (ARHI), or presbycusis, is a very common multifactorial disorder. Despite the knowledge that genetics play an important role in the etiology of human ARHI as revealed by heritability studies, to date, its precise genetic determinants remain elusive. Here we report the results of a cross-sectional family-based genetic study employing audiometric data. By using principal component analysis, we were able to reduce the dimensionality of this multivariate phenotype while capturing most of the variation and retaining biologically important features of the audiograms. We conducted a genome-wide association as well as a linkage scan with high-density SNP microarrays. Because of the presence of genetic population substructure, association testing was stratified after which evidence was combined by meta-analysis. No association signals reaching genome-wide significance were detected. Linkage analysis identified a linkage peak on 8q24.13-q24.22 for a trait correlated to audiogram shape. The signal reached genome-wide significance, as assessed by simulations. This finding represents the first locus for an ARHI trait.

  11. Genome-wide patterns of recombination, linkage disequilibrium and nucleotide diversity from pooled resequencing and single nucleotide polymorphism genotyping unlock the evolutionary history of Eucalyptus grandis.

    PubMed

    Silva-Junior, Orzenil B; Grattapaglia, Dario

    2015-11-01

    We used high-density single nucleotide polymorphism (SNP) data and whole-genome pooled resequencing to examine the landscape of population recombination (ρ) and nucleotide diversity (ϴw ), assess the extent of linkage disequilibrium (r(2) ) and build the highest density linkage maps for Eucalyptus. At the genome-wide level, linkage disequilibrium (LD) decayed within c. 4-6 kb, slower than previously reported from candidate gene studies, but showing considerable variation from absence to complete LD up to 50 kb. A sharp decrease in the estimate of ρ was seen when going from short to genome-wide inter-SNP distances, highlighting the dependence of this parameter on the scale of observation adopted. Recombination was correlated with nucleotide diversity, gene density and distance from the centromere, with hotspots of recombination enriched for genes involved in chemical reactions and pathways of the normal metabolic processes. The high nucleotide diversity (ϴw = 0.022) of E. grandis revealed that mutation is more important than recombination in shaping its genomic diversity (ρ/ϴw = 0.645). Chromosome-wide ancestral recombination graphs allowed us to date the split of E. grandis (1.7-4.8 million yr ago) and identify a scenario for the recent demographic history of the species. Our results have considerable practical importance to Genome Wide Association Studies (GWAS), while indicating bright prospects for genomic prediction of complex phenotypes in eucalypt breeding. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  12. Genome-wide linkage scan for plasma high density lipoprotein cholesterol, apolipoprotein A-1 and triglyceride variation among American Indian populations: the Strong Heart Family Study

    PubMed Central

    Li, X; Monda, KL.; Göring, HHH; Haack, K; Cole, SA; Diego, VP; Almasy, L; Laston, S; Howard, BV; Shara, NM; Lee, ET; Best, LG; Fabsitz, RR; MacCluer, JW; North, KE

    2011-01-01

    Background Recent studies have identified chromosomal regions linked to variation in high density lipoprotein cholesterol (HDL-C), apolipoprotein A-1 (Apo A-1) and triglyceride (TG), although results have been inconsistent and previous studies of American Indian populations are limited Objective In an attempt to localize quantitative trait loci (QTLs) influencing HDL-C, Apo A-1 and TG, we conducted genome-wide linkage scans of subjects of the Strong Heart Family Study. Methods We implemented analyses in 3484 men and women aged 18 years or older, at three study centers. Results With adjustment for age, sex and center, we detected a QTL influencing both HDL-C (LOD = 4.4, genome-wide P = 0.001) and Apo A-1 (LOD = 3.2, genome-wide P = 0.020) nearest marker D6S289 at 6p23 in the Arizona sample. Another QTL influencing Apo A-1 was found nearest marker D9S287 at 9q22.2 (LOD = 3.0, genome-wide P = 0.033) in the North and South Dakotas. We detected a QTL influencing TG nearest marker D15S153 at 15q22.31 (LOD = 4.5 in the overall sample and LOD = 3.8 in the Dakotas sample, genome-wide P = 0.0044) and when additionally adjusted for waist, current smoking, current alcohol, current estrogen, lipid treatment, impaired fasting glucose, and diabetes, nearest marker D10S217 at 10q26.2 (LOD = 3.7, genome-wide P = 0.0058) in the Arizona population. Conclusions The replication of QTLs in regions of the genome that harbor well-known candidate genes suggest that chromosomes 6p, 9q and 15q warrant further investigation with fine mapping for causative polymorphisms in American Indians. PMID:19429595

  13. Genome-wide Scan and Fine-Mapping Linkage Study of Androgenetic Alopecia Reveals a Locus on Chromosome 3q26

    PubMed Central

    Hillmer, Axel M.; Flaquer, Antonia; Hanneken, Sandra; Eigelshoven, Sibylle; Kortüm, Anne-Katrin; Brockschmidt, Felix F.; Golla, Astrid; Metzen, Christine; Thiele, Holger; Kolberg, Susanne; Reinartz, Roman; Betz, Regina C.; Ruzicka, Thomas; Hennies, Hans Christian; Kruse, Roland; Nöthen, Markus M.

    2008-01-01

    Androgenetic alopecia (AGA, male pattern baldness) is the most common form of hair loss. The origin of AGA is genetic, with the X chromosome located androgen receptor gene (AR) being the only risk gene identified to date. We present the results of a genome-wide linkage study of 95 families and linkage fine mapping of the 3q21-q29, 11q14-q25, 18p11-q23, and 19p13-q13 regions in an extended sample of 125 families of German descent. The locus with strongest evidence for linkage was mapped to 3q26 with a nonparametric linkage (NPL) score of 3.97 (empirical p value = 0.00055). This is the first step toward the identification of new susceptibility genes in AGA, a process which will provide important insights into the molecular and cellular basis of scalp hair loss. PMID:18304493

  14. Genome-Wide Linkage Scan to Identify Loci Associated with Type 2 Diabetes and Blood Lipid Phenotypes in the Sikh Diabetes Study

    PubMed Central

    Sanghera, Dharambir K.; Been, Latonya F.; Ralhan, Sarju; Wander, Gurpreet S.; Mehra, Narinder K.; Singh, Jai Rup; Ferrell, Robert E.; Kamboh, Mohammed I.; Aston, Christopher E.

    2011-01-01

    In this investigation, we have carried out an autosomal genome-wide linkage analysis to map genes associated with type 2 diabetes (T2D) and five quantitative traits of blood lipids including total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL) cholesterol, and triglycerides in a unique family-based cohort from the Sikh Diabetes Study (SDS). A total of 870 individuals (526 male/344 female) from 321 families were successfully genotyped using 398 polymorphic microsatellite markers with an average spacing of 9.26 cM on the autosomes. Results of non-parametric multipoint linkage analysis using Sall statistics (implemented in Merlin) did not reveal any chromosomal region to be significantly associated with T2D in this Sikh cohort. However, linkage analysis for lipid traits using QTL-ALL analysis revealed promising linkage signals with p≤0.005 for total cholesterol, LDL cholesterol, and HDL cholesterol at chromosomes 5p15, 9q21, 10p11, 10q21, and 22q13. The most significant signal (p = 0.0011) occurred at 10q21.2 for HDL cholesterol. We also observed linkage signals for total cholesterol at 22q13.32 (p = 0.0016) and 5p15.33 (p = 0.0031) and for LDL cholesterol at 10p11.23 (p = 0.0045). Interestingly, some of linkage regions identified in this Sikh population coincide with plausible candidate genes reported in recent genome-wide association and meta-analysis studies for lipid traits. Our study provides the first evidence of linkage for loci associated with quantitative lipid traits at four chromosomal regions in this Asian Indian population from Punjab. More detailed examination of these regions with more informative genotyping, sequencing, and functional studies should lead to rapid detection of novel targets of therapeutic importance. PMID:21698157

  15. Search and Validation of Short Genome-Wide Biomarkers for Bacterial Biological Phylogenies

    NASA Astrophysics Data System (ADS)

    Garzon, Max H.; Wong, Tit-Yee

    We continue the exploration of DNA-based indexing as a universal coordinate system in DNA spaces to characterize very large groups (families, genera, and even phylla) of organisms on a uniform biomarker reference system, a comprehensive "Atlas of Life", as it is or as it could be on earth. We provide a second confirmation that DNA noncrosshybridizing (nxh) sets can be successfully applied to infer ab-initio phylogenetic trees by providing a method to measure distances among entire genomes indexed by sets of short oligonucleotides selected so as to minimize crosshybridization. These phylogenies are solidly established and well accepted in bacterial biology, albeit done by analyses of relatively small segments of highly conserved rybozomic DNA. Second, it is further demonstrated that DNA indexing does provide novel and principled genome-wide predictions into the phylogenesis of organisms hitherto inaccessible by current methods, such as a prediction of the origin of the Salmonella plasmid 50 as being acquired horizontally, likely from some bacteria somewhat related to Yesinia. We conclude with some discussion about the scalability and potential of this method to develop a comprehensive tree of life based on genome-wide methods.

  16. A genome-wide association search for type 2 diabetes genes in African Americans.

    PubMed

    Palmer, Nicholette D; McDonough, Caitrin W; Hicks, Pamela J; Roh, Bong H; Wing, Maria R; An, S Sandy; Hester, Jessica M; Cooke, Jessica N; Bostrom, Meredith A; Rudock, Megan E; Talbert, Matthew E; Lewis, Joshua P; Ferrara, Assiamira; Lu, Lingyi; Ziegler, Julie T; Sale, Michele M; Divers, Jasmin; Shriner, Daniel; Adeyemo, Adebowale; Rotimi, Charles N; Ng, Maggie C Y; Langefeld, Carl D; Freedman, Barry I; Bowden, Donald W; Voight, Benjamin F; Scott, Laura J; Steinthorsdottir, Valgerdur; Morris, Andrew P; Dina, Christian; Welch, Ryan P; Zeggini, Eleftheria; Huth, Cornelia; Aulchenko, Yurii S; Thorleifsson, Gudmar; McCulloch, Laura J; Ferreira, Teresa; Grallert, Harald; Amin, Najaf; Wu, Guanming; Willer, Cristen J; Raychaudhuri, Soumya; McCarroll, Steve A; Langenberg, Claudia; Hofmann, Oliver M; Dupuis, Josée; Qi, Lu; Segrè, Ayellet V; van Hoek, Mandy; Navarro, Pau; Ardlie, Kristin; Balkau, Beverley; Benediktsson, Rafn; Bennett, Amanda J; Blagieva, Roza; Boerwinkle, Eric; Bonnycastle, Lori L; Boström, Kristina Bengtsson; Bravenboer, Bert; Bumpstead, Suzannah; Burtt, Noël P; Charpentier, Guillaume; Chines, Peter S; Cornelis, Marilyn; Couper, David J; Crawford, Gabe; Doney, Alex S F; Elliott, Katherine S; Elliott, Amanda L; Erdos, Michael R; Fox, Caroline S; Franklin, Christopher S; Ganser, Martha; Gieger, Christian; Grarup, Niels; Green, Todd; Griffin, Simon; Groves, Christopher J; Guiducci, Candace; Hadjadj, Samy; Hassanali, Neelam; Herder, Christian; Isomaa, Bo; Jackson, Anne U; Johnson, Paul R V; Jørgensen, Torben; Kao, Wen H L; Klopp, Norman; Kong, Augustine; Kraft, Peter; Kuusisto, Johanna; Lauritzen, Torsten; Li, Man; Lieverse, Aloysius; Lindgren, Cecilia M; Lyssenko, Valeriya; Marre, Michel; Meitinger, Thomas; Midthjell, Kristian; Morken, Mario A; Narisu, Narisu; Nilsson, Peter; Owen, Katharine R; Payne, Felicity; Perry, John R B; Petersen, Ann-Kristin; Platou, Carl; Proença, Christine; Prokopenko, Inga; Rathmann, Wolfgang; Rayner, N William; Robertson, Neil R; Rocheleau, Ghislain; Roden, Michael; Sampson, Michael J; Saxena, Richa; Shields, Beverley M; Shrader, Peter; Sigurdsson, Gunnar; Sparsø, Thomas; Strassburger, Klaus; Stringham, Heather M; Sun, Qi; Swift, Amy J; Thorand, Barbara; Tichet, Jean; Tuomi, Tiinamaija; van Dam, Rob M; van Haeften, Timon W; van Herpt, Thijs; van Vliet-Ostaptchouk, Jana V; Walters, G Bragi; Weedon, Michael N; Wijmenga, Cisca; Witteman, Jacqueline; Bergman, Richard N; Cauchi, Stephane; Collins, Francis S; Gloyn, Anna L; Gyllensten, Ulf; Hansen, Torben; Hide, Winston A; Hitman, Graham A; Hofman, Albert; Hunter, David J; Hveem, Kristian; Laakso, Markku; Mohlke, Karen L; Morris, Andrew D; Palmer, Colin N A; Pramstaller, Peter P; Rudan, Igor; Sijbrands, Eric; Stein, Lincoln D; Tuomilehto, Jaakko; Uitterlinden, Andre; Walker, Mark; Wareham, Nicholas J; Watanabe, Richard M; Abecasis, Goncalo R; Boehm, Bernhard O; Campbell, Harry; Daly, Mark J; Hattersley, Andrew T; Hu, Frank B; Meigs, James B; Pankow, James S; Pedersen, Oluf; Wichmann, H-Erich; Barroso, Inês; Florez, Jose C; Frayling, Timothy M; Groop, Leif; Sladek, Rob; Thorsteinsdottir, Unnur; Wilson, James F; Illig, Thomas; Froguel, Philippe; van Duijn, Cornelia M; Stefansson, Kari; Altshuler, David; Boehnke, Michael; McCarthy, Mark I; Soranzo, Nicole; Wheeler, Eleanor; Glazer, Nicole L; Bouatia-Naji, Nabila; Mägi, Reedik; Randall, Joshua; Johnson, Toby; Elliott, Paul; Rybin, Denis; Henneman, Peter; Dehghan, Abbas; Hottenga, Jouke Jan; Song, Kijoung; Goel, Anuj; Egan, Josephine M; Lajunen, Taina; Doney, Alex; Kanoni, Stavroula; Cavalcanti-Proença, Christine; Kumari, Meena; Timpson, Nicholas J; Zabena, Carina; Ingelsson, Erik; An, Ping; O'Connell, Jeffrey; Luan, Jian'an; Elliott, Amanda; McCarroll, Steven A; Roccasecca, Rosa Maria; Pattou, François; Sethupathy, Praveen; Ariyurek, Yavuz; Barter, Philip; Beilby, John P; Ben-Shlomo, Yoav; Bergmann, Sven; Bochud, Murielle; Bonnefond, Amélie; Borch-Johnsen, Knut; Böttcher, Yvonne; Brunner, Eric; Bumpstead, Suzannah J; Chen, Yii-Der Ida; Chines, Peter; Clarke, Robert; Coin, Lachlan J M; Cooper, Matthew N; Crisponi, Laura; Day, Ian N M; de Geus, Eco J C; Delplanque, Jerome; Fedson, Annette C; Fischer-Rosinsky, Antje; Forouhi, Nita G; Frants, Rune; Franzosi, Maria Grazia; Galan, Pilar; Goodarzi, Mark O; Graessler, Jürgen; Grundy, Scott; Gwilliam, Rhian; Hallmans, Göran; Hammond, Naomi; Han, Xijing; Hartikainen, Anna-Liisa; Hayward, Caroline; Heath, Simon C; Hercberg, Serge; Hicks, Andrew A; Hillman, David R; Hingorani, Aroon D; Hui, Jennie; Hung, Joe; Jula, Antti; Kaakinen, Marika; Kaprio, Jaakko; Kesaniemi, Y Antero; Kivimaki, Mika; Knight, Beatrice; Koskinen, Seppo; Kovacs, Peter; Kyvik, Kirsten Ohm; Lathrop, G Mark; Lawlor, Debbie A; Le Bacquer, Olivier; Lecoeur, Cécile; Li, Yun; Mahley, Robert; Mangino, Massimo; Manning, Alisa K; Martínez-Larrad, María Teresa; McAteer, Jarred B; McPherson, Ruth; Meisinger, Christa; Melzer, David; Meyre, David; Mitchell, Braxton D; Mukherjee, Sutapa; Naitza, Silvia; Neville, Matthew J; Oostra, Ben A; Orrù, Marco; Pakyz, Ruth; Paolisso, Giuseppe; Pattaro, Cristian; Pearson, Daniel; Peden, John F; Pedersen, Nancy L; Perola, Markus; Pfeiffer, Andreas F H; Pichler, Irene; Polasek, Ozren; Posthuma, Danielle; Potter, Simon C; Pouta, Anneli; Province, Michael A; Psaty, Bruce M; Rayner, Nigel W; Rice, Kenneth; Ripatti, Samuli; Rivadeneira, Fernando; Rolandsson, Olov; Sandbaek, Annelli; Sandhu, Manjinder; Sanna, Serena; Sayer, Avan Aihie; Scheet, Paul; Seedorf, Udo; Sharp, Stephen J; Shields, Beverley; Sijbrands, Eric J G; Silveira, Angela; Simpson, Laila; Singleton, Andrew; Smith, Nicholas L; Sovio, Ulla; Swift, Amy; Syddall, Holly; Syvänen, Ann-Christine; Tanaka, Toshiko; Tönjes, Anke; Uitterlinden, André G; van Dijk, Ko Willems; Varma, Dhiraj; Visvikis-Siest, Sophie; Vitart, Veronique; Vogelzangs, Nicole; Waeber, Gérard; Wagner, Peter J; Walley, Andrew; Ward, Kim L; Watkins, Hugh; Wild, Sarah H; Willemsen, Gonneke; Witteman, Jaqueline C M; Yarnell, John W G; Zelenika, Diana; Zethelius, Björn; Zhai, Guangju; Zhao, Jing Hua; Zillikens, M Carola; Borecki, Ingrid B; Loos, Ruth J F; Meneton, Pierre; Magnusson, Patrik K E; Nathan, David M; Williams, Gordon H; Silander, Kaisa; Salomaa, Veikko; Smith, George Davey; Bornstein, Stefan R; Schwarz, Peter; Spranger, Joachim; Karpe, Fredrik; Shuldiner, Alan R; Cooper, Cyrus; Dedoussis, George V; Serrano-Ríos, Manuel; Lind, Lars; Palmer, Lyle J; Franks, Paul W; Ebrahim, Shah; Marmot, Michael; Kao, W H Linda; Pramstaller, Peter Paul; Wright, Alan F; Stumvoll, Michael; Hamsten, Anders; Buchanan, Thomas A; Valle, Timo T; Rotter, Jerome I; Siscovick, David S; Penninx, Brenda W J H; Boomsma, Dorret I; Deloukas, Panos; Spector, Timothy D; Ferrucci, Luigi; Cao, Antonio; Scuteri, Angelo; Schlessinger, David; Uda, Manuela; Ruokonen, Aimo; Jarvelin, Marjo-Riitta; Waterworth, Dawn M; Vollenweider, Peter; Peltonen, Leena; Mooser, Vincent; Sladek, Robert

    2012-01-01

    African Americans are disproportionately affected by type 2 diabetes (T2DM) yet few studies have examined T2DM using genome-wide association approaches in this ethnicity. The aim of this study was to identify genes associated with T2DM in the African American population. We performed a Genome Wide Association Study (GWAS) using the Affymetrix 6.0 array in 965 African-American cases with T2DM and end-stage renal disease (T2DM-ESRD) and 1029 population-based controls. The most significant SNPs (n = 550 independent loci) were genotyped in a replication cohort and 122 SNPs (n = 98 independent loci) were further tested through genotyping three additional validation cohorts followed by meta-analysis in all five cohorts totaling 3,132 cases and 3,317 controls. Twelve SNPs had evidence of association in the GWAS (P<0.0071), were directionally consistent in the Replication cohort and were associated with T2DM in subjects without nephropathy (P<0.05). Meta-analysis in all cases and controls revealed a single SNP reaching genome-wide significance (P<2.5×10(-8)). SNP rs7560163 (P = 7.0×10(-9), OR (95% CI) = 0.75 (0.67-0.84)) is located intergenically between RND3 and RBM43. Four additional loci (rs7542900, rs4659485, rs2722769 and rs7107217) were associated with T2DM (P<0.05) and reached more nominal levels of significance (P<2.5×10(-5)) in the overall analysis and may represent novel loci that contribute to T2DM. We have identified novel T2DM-susceptibility variants in the African-American population. Notably, T2DM risk was associated with the major allele and implies an interesting genetic architecture in this population. These results suggest that multiple loci underlie T2DM susceptibility in the African-American population and that these loci are distinct from those identified in other ethnic populations.

  17. A Genome-Wide Association Search for Type 2 Diabetes Genes in African Americans

    PubMed Central

    Palmer, Nicholette D.; McDonough, Caitrin W.; Hicks, Pamela J.; Roh, Bong H.; Wing, Maria R.; An, S. Sandy; Hester, Jessica M.; Cooke, Jessica N.; Bostrom, Meredith A.; Rudock, Megan E.; Talbert, Matthew E.; Lewis, Joshua P.; Ferrara, Assiamira; Lu, Lingyi; Ziegler, Julie T.; Sale, Michele M.; Divers, Jasmin; Shriner, Daniel; Adeyemo, Adebowale; Rotimi, Charles N.; Ng, Maggie C. Y.; Langefeld, Carl D.; Freedman, Barry I.; Bowden, Donald W.

    2012-01-01

    African Americans are disproportionately affected by type 2 diabetes (T2DM) yet few studies have examined T2DM using genome-wide association approaches in this ethnicity. The aim of this study was to identify genes associated with T2DM in the African American population. We performed a Genome Wide Association Study (GWAS) using the Affymetrix 6.0 array in 965 African-American cases with T2DM and end-stage renal disease (T2DM-ESRD) and 1029 population-based controls. The most significant SNPs (n = 550 independent loci) were genotyped in a replication cohort and 122 SNPs (n = 98 independent loci) were further tested through genotyping three additional validation cohorts followed by meta-analysis in all five cohorts totaling 3,132 cases and 3,317 controls. Twelve SNPs had evidence of association in the GWAS (P<0.0071), were directionally consistent in the Replication cohort and were associated with T2DM in subjects without nephropathy (P<0.05). Meta-analysis in all cases and controls revealed a single SNP reaching genome-wide significance (P<2.5×10−8). SNP rs7560163 (P = 7.0×10−9, OR (95% CI) = 0.75 (0.67–0.84)) is located intergenically between RND3 and RBM43. Four additional loci (rs7542900, rs4659485, rs2722769 and rs7107217) were associated with T2DM (P<0.05) and reached more nominal levels of significance (P<2.5×10−5) in the overall analysis and may represent novel loci that contribute to T2DM. We have identified novel T2DM-susceptibility variants in the African-American population. Notably, T2DM risk was associated with the major allele and implies an interesting genetic architecture in this population. These results suggest that multiple loci underlie T2DM susceptibility in the African-American population and that these loci are distinct from those identified in other ethnic populations. PMID:22238593

  18. A combined genome-wide linkage and association approach to find susceptibility loci for platelet function phenotypes in European American and African American families with coronary artery disease.

    PubMed

    Mathias, Rasika A; Kim, Yoonhee; Sung, Heejong; Yanek, Lisa R; Mantese, V J; Hererra-Galeano, J Enrique; Ruczinski, Ingo; Wilson, Alexander F; Faraday, Nauder; Becker, Lewis C; Becker, Diane M

    2010-06-07

    The inability of aspirin (ASA) to adequately suppress platelet aggregation is associated with future risk of coronary artery disease (CAD). Heritability studies of agonist-induced platelet function phenotypes suggest that genetic variation may be responsible for ASA responsiveness. In this study, we leverage independent information from genome-wide linkage and association data to determine loci controlling platelet phenotypes before and after treatment with ASA. Clinical data on 37 agonist-induced platelet function phenotypes were evaluated before and after a 2-week trial of ASA (81 mg/day) in 1231 European American and 846 African American healthy subjects with a family history of premature CAD. Principal component analysis was performed to minimize the number of independent factors underlying the covariance of these various phenotypes. Multi-point sib-pair based linkage analysis was performed using a microsatellite marker set, and single-SNP association tests were performed using markers from the Illumina 1 M genotyping chip from deCODE Genetics, Inc. All analyses were performed separately within each ethnic group. Several genomic regions appear to be linked to ASA response factors: a 10 cM region in African Americans on chromosome 5q11.2 had several STRs with suggestive (p-value < 7 x 10-4) and significant (p-value < 2 x 10-5) linkage to post aspirin platelet response to ADP, and ten additional factors had suggestive evidence for linkage (p-value < 7 x 10-4) to thirteen genomic regions. All but one of these factors were aspirin response variables. While the strength of genome-wide SNP association signals for factors showing evidence for linkage is limited, especially at the strict thresholds of genome-wide criteria (N = 9 SNPs for 11 factors), more signals were considered significant when the association signal was weighted by evidence for linkage (N = 30 SNPs). Our study supports the hypothesis that platelet phenotypes in response to ASA likely have genetic

  19. A combined genome-wide linkage and association approach to find susceptibility loci for platelet function phenotypes in European American and African American families with coronary artery disease

    PubMed Central

    2010-01-01

    Background The inability of aspirin (ASA) to adequately suppress platelet aggregation is associated with future risk of coronary artery disease (CAD). Heritability studies of agonist-induced platelet function phenotypes suggest that genetic variation may be responsible for ASA responsiveness. In this study, we leverage independent information from genome-wide linkage and association data to determine loci controlling platelet phenotypes before and after treatment with ASA. Methods Clinical data on 37 agonist-induced platelet function phenotypes were evaluated before and after a 2-week trial of ASA (81 mg/day) in 1231 European American and 846 African American healthy subjects with a family history of premature CAD. Principal component analysis was performed to minimize the number of independent factors underlying the covariance of these various phenotypes. Multi-point sib-pair based linkage analysis was performed using a microsatellite marker set, and single-SNP association tests were performed using markers from the Illumina 1 M genotyping chip from deCODE Genetics, Inc. All analyses were performed separately within each ethnic group. Results Several genomic regions appear to be linked to ASA response factors: a 10 cM region in African Americans on chromosome 5q11.2 had several STRs with suggestive (p-value < 7 × 10-4) and significant (p-value < 2 × 10-5) linkage to post aspirin platelet response to ADP, and ten additional factors had suggestive evidence for linkage (p-value < 7 × 10-4) to thirteen genomic regions. All but one of these factors were aspirin response variables. While the strength of genome-wide SNP association signals for factors showing evidence for linkage is limited, especially at the strict thresholds of genome-wide criteria (N = 9 SNPs for 11 factors), more signals were considered significant when the association signal was weighted by evidence for linkage (N = 30 SNPs). Conclusions Our study supports the hypothesis that platelet phenotypes

  20. Genome-wide linkage survey for genetic loci that affect the risk of suicide attempts in families with recurrent, early-onset, major depression.

    PubMed

    Zubenko, George S; Maher, Brion S; Hughes, Hugh B; Zubenko, Wendy N; Scott Stiffler, J; Marazita, Mary L

    2004-08-15

    We previously described the results of a genome-wide linkage survey for genetic loci that influenced the development of unipolar mood disorders in 81 families identified by individuals with Recurrent, Early-Onset, Major Depressive Disorder (RE-MDD) [Zubenko et al. 2003b; Am J Med Genet (Neuropsychiatr Genet) 123B:1-18]. In the current study, we extended this linkage analysis by including the history of a suicide attempt as a covariate to identify chromosomal regions that harbor genes that influence the risk of this behavior in the context of mood disorders. This approach identified six linkage peaks with maximum multipoint DeltaLOD scores that reached genome-wide adjusted levels of significance (2p, 5q, 6q, 8p, 11q, and Xq). Four of these (2p, 6q, 8p, and Xq) exceeded the criterion for "highly-significant linkage" (genome-wide adjusted P < 0.001) recommended by Lander and Kruglyak [1995; Nat Genet 11:241-246]. The strongest evidence for linkage was observed in analyses employing affected relative pairs (ARPs) with the most severe and disabling Mood Disorders: Depression Spectrum Disorder and RE-MDD. The highest DeltaLOD score that emerged from this linkage analysis, 5.08, occurred for ARPs with Depression Spectrum Disorder at D8S1145 (37.0 cM, 18.2 Mbps, P < 0.0001) at cytogenetic location 8p22-p21. Significant linkage results on Xq arose from analyses of ARPs with RE-MDD at DXS1047 (143 cM, 127.8 Mbps, DeltaLOD = 3.87, P < 0.0001), a finding that may contribute to the higher rate of suicide attempts among women than men. These findings provide evidence for suicide risk loci that are independent of susceptibility loci for Mood Disorders, and suggest that the capacity for suicide risk loci to affect the development of suicidal behavior depends on the psychiatric disorder or subtype with which they interact. Copyright 2004 Wiley-Liss, Inc.

  1. A Genome-Wide Search for Greek and Jewish Admixture in the Kashmiri Population

    PubMed Central

    Tashi, Tsewang; Lorenzo, Felipe Ramos; Feusier, Julie Ellen; Mir, Hyder

    2016-01-01

    The Kashmiri population is an ethno-linguistic group that resides in the Kashmir Valley in northern India. A longstanding hypothesis is that this population derives ancestry from Jewish and/or Greek sources. There is historical and archaeological evidence of ancient Greek presence in India and Kashmir. Further, some historical accounts suggest ancient Hebrew ancestry as well. To date, it has not been determined whether signatures of Greek or Jewish admixture can be detected in the Kashmiri population. Using genome-wide genotyping and admixture detection methods, we determined there are no significant or substantial signs of Greek or Jewish admixture in modern-day Kashmiris. The ancestry of Kashmiri Tibetans was also determined, which showed signs of admixture with populations from northern India and west Eurasia. These results contribute to our understanding of the existing population structure in northern India and its surrounding geographical areas. PMID:27490348

  2. A Genome-Wide Search for Greek and Jewish Admixture in the Kashmiri Population.

    PubMed

    Downie, Jonathan M; Tashi, Tsewang; Lorenzo, Felipe Ramos; Feusier, Julie Ellen; Mir, Hyder; Prchal, Josef T; Jorde, Lynn B; Koul, Parvaiz A

    2016-01-01

    The Kashmiri population is an ethno-linguistic group that resides in the Kashmir Valley in northern India. A longstanding hypothesis is that this population derives ancestry from Jewish and/or Greek sources. There is historical and archaeological evidence of ancient Greek presence in India and Kashmir. Further, some historical accounts suggest ancient Hebrew ancestry as well. To date, it has not been determined whether signatures of Greek or Jewish admixture can be detected in the Kashmiri population. Using genome-wide genotyping and admixture detection methods, we determined there are no significant or substantial signs of Greek or Jewish admixture in modern-day Kashmiris. The ancestry of Kashmiri Tibetans was also determined, which showed signs of admixture with populations from northern India and west Eurasia. These results contribute to our understanding of the existing population structure in northern India and its surrounding geographical areas.

  3. White matter lesion progression: A genome-wide search for genetic influences

    PubMed Central

    Hofer, Edith; Cavalieri, Margherita; Bis, Joshua C; DeCarli, Charles; Fornage, Myriam; Sigurdsson, Sigurdur; Srikanth, Velandai; Trompet, Stella; Verhaaren, Benjamin FJ; Wolf, Christiane; Yang, Qiong; Adams, Hieab HH; Amouyel, Philippe; Beiser, Alexa; Buckley, Brendan M; Callisaya, Michele; Chauhan, Ganesh; de Craen, Anton JM; Dufouil, Carole; van Duijn, Cornelia M; Ford, Ian; Freudenberger, Paul; Gottesman, Rebecca F; Gudnason, Vilmundur; Heiss, Gerardo; Hofman, Albert; Lumley, Thomas; Martinez, Oliver; Mazoyer, Bernard; Moran, Chris; Niessen, Wiro J.; Phan, Thanh; Psaty, Bruce M; Satizabal, Claudia L; Sattar, Naveed; Schilling, Sabrina; Shibata, Dean K; Slagboom, P Eline; Smith, Albert; Stott, David J; Taylor, Kent D; Thomson, Russell; Töglhofer, Anna M; Tzourio, Christophe; van Buchem, Mark; Wang, Jing; Westendorp, Rudi GJ; Windham, B Gwen; Vernooij, Meike W; Zijdenbos, Alex; Beare, Richard; Debette, Stéphanie; Ikram, M Arfan; Jukema, J Wouter; Launer, Lenore J; Longstreth, W T; Mosley, Thomas H; Seshadri, Sudha; Schmidt, Helena; Schmidt, Reinhold

    2016-01-01

    Background and Purpose White matter lesion (WML) progression on magnetic resonance imaging (MRI) is related to cognitive decline and stroke, but its determinants besides baseline WML burden are largely unknown. Here, we estimated heritability of WML progression, and sought common genetic variants associated with WML progression in elderly participants from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium. Methods Heritability of WML progression was calculated in the Framingham Heart Study. The genome-wide association study included 7773 elderly participants from 10 cohorts. To assess the relative contribution of genetic factors to progression of WML, we compared in seven cohorts risk models including demographics, vascular risk factors plus single nucleotide polymorphisms (SNPs) that have been shown to be associated cross-sectionally with WML in the current and previous association studies. Results A total of 1085 subjects showed WML progression. The heritability estimate for WML progression was low at 6.5%, and no SNPs achieved genome-wide significance (p-value < 5×10−8). Four loci were suggestive (p-value < 1×10−5) of an association with WML progression: 10q24.32 (rs10883817, p=1.46×10−6); 12q13.13 (rs4761974, p=8.71×10−7); 20p12.1 (rs6135309, p=3.69×10−6); and 4p15.31 (rs7664442, p=2.26×10−6). Variants that have been previously related to WML explained only 0.8% to 11.7% more of the variance in WML progression than age, vascular risk factors and baseline WML burden. Conclusions Common genetic factors contribute little to the progression of age-related WML in middle-aged and older adults. Future research on determinants of WML progression should focus more on environmental, life-style or host-related biological factors. PMID:26451028

  4. A genome-wide linkage scan of bipolar disorder in Latino families identifies susceptibility loci at 8q24 and 14q32.

    PubMed

    Gonzalez, Suzanne; Camarillo, Cynthia; Rodriguez, Marco; Ramirez, Mercedes; Zavala, Juan; Armas, Regina; Contreras, Salvador A; Contreras, Javier; Dassori, Albana; Almasy, Laura; Flores, Deborah; Jerez, Alvaro; Raventós, Henriette; Ontiveros, Alfonso; Nicolini, Humberto; Escamilla, Michael

    2014-09-01

    A genome-wide nonparametric linkage screen was performed to localize Bipolar Disorder (BP) susceptibility loci in a sample of 3757 individuals of Latino ancestry. The sample included 963 individuals with BP phenotype (704 relative pairs) from 686 families recruited from the US, Mexico, Costa Rica, and Guatemala. Non-parametric analyses were performed over a 5 cM grid with an average genetic coverage of 0.67 cM. Multipoint analyses were conducted across the genome using non-parametric Kong & Cox LOD scores along with Sall statistics for all relative pairs. Suggestive and significant genome-wide thresholds were calculated based on 1000 simulations. Single-marker association tests in the presence of linkage were performed assuming a multiplicative model with a population prevalence of 2%. We identified two genome-wide significant susceptibly loci for BP at 8q24 and 14q32, and a third suggestive locus at 2q13-q14. Within these three linkage regions, the top associated single marker (rs1847694, P = 2.40 × 10(-5)) is located 195 Kb upstream of DPP10 in Chromosome 2. DPP10 is prominently expressed in brain neuronal populations, where it has been shown to bind and regulate Kv4-mediated A-type potassium channels. Taken together, these results provide additional evidence that 8q24, 14q32, and 2q13-q14 are susceptibly loci for BP and these regions may be involved in the pathogenesis of BP in the Latino population. © 2014 Wiley Periodicals, Inc.

  5. Genome-wide linkage mapping of QTL for black point reaction in bread wheat (Triticum aestivum L.).

    PubMed

    Liu, Jindong; He, Zhonghu; Wu, Ling; Bai, Bin; Wen, Weie; Xie, Chaojie; Xia, Xianchun

    2016-11-01

    Nine QTL for black point resistance in wheat were identified using a RIL population derived from a Linmai 2/Zhong 892 cross and 90K SNP assay. Black point, discoloration of the embryo end of the grain, downgrades wheat grain quality leading to significant economic losses to the wheat industry. The availability of molecular markers will accelerate improvement of black point resistance in wheat breeding. The aims of this study were to identify quantitative trait loci (QTL) for black point resistance and tightly linked molecular markers, and to search for candidate genes using a high-density genetic linkage map of wheat. A recombinant inbred line (RIL) population derived from the cross Linmai 2/Zhong 892 was evaluated for black point reaction during the 2011-2012, 2012-2013 and 2013-2014 cropping seasons, providing data for seven environments. A high-density linkage map was constructed by genotyping the RILs with the wheat 90K single nucleotide polymorphism (SNP) chip. Composite interval mapping detected nine QTL on chromosomes 2AL, 2BL, 3AL, 3BL, 5AS, 6A, 7AL (2) and 7BS, designated as QBp.caas-2AL, QBp.caas-2BL, QBp.caas-3AL, QBp.caas-3BL, QBp.caas-5AS, QBp.caas-6A, QBp.caas-7AL.1, QBp.caas-7AL.2 and QBp.caas-7BS, respectively. All resistance alleles, except for QBp.caas-7AL.1 from Linmai 2, were contributed by Zhong 892. QBp.caas-3BL, QBp.caas-5AS, QBp.caas-7AL.1, QBp.caas-7AL.2 and QBp.caas-7BS probably represent new loci for black point resistance. Sequences of tightly linked SNPs were used to survey wheat and related cereal genomes identifying three candidate genes for black point resistance. The tightly linked SNP markers can be used in marker-assisted breeding in combination with the kompetitive allele specific PCR technique to improve black point resistance.

  6. Genome-wide association and linkage identify modifier loci of lung disease severity in cystic fibrosis at 11p13 and 20q13.2

    PubMed Central

    Wright, Fred A.; Strug, Lisa J.; Doshi, Vishal K.; Commander, Clayton W.; Blackman, Scott M.; Sun, Lei; Berthiaume, Yves; Cutler, David; Cojocaru, Andreea; Collaco, J. Michael; Corey, Mary; Dorfman, Ruslan; Goddard, Katrina; Green, Deanna; Kent, Jack W.; Lange, Ethan M.; Lee, Seunggeun; Li, Weili; Luo, Jingchun; Mayhew, Gregory M.; Naughton, Kathleen M.; Pace, Rhonda G.; Paré, Peter; Rommens, Johanna M.; Sandford, Andrew; Stonebraker, Jaclyn R.; Sun, Wei; Taylor, Chelsea; Vanscoy, Lori L.; Zou, Fei; Blangero, John; Zielenski, Julian; O’Neal, Wanda K.; Drumm, Mitchell L.; Durie, Peter R.; Knowles, Michael R.; Cutting, Garry R.

    2012-01-01

    A combined genome-wide association and linkage study was used to identify loci causing variation in CF lung disease severity. A significant association (P=3. 34 × 10-8) near EHF and APIP (chr11p13) was identified in F508del homozygotes (n=1,978). The association replicated in F508del homozygotes (P=0.006) from a separate family-based study (n=557), with P=1.49 × 10-9 for the three-study joint meta-analysis. Linkage analysis of 486 sibling pairs from the family-based study identified a significant QTL on chromosome 20q13.2 (LOD=5.03). Our findings provide insight into the causes of variation in lung disease severity in CF and suggest new therapeutic targets for this life-limiting disorder. PMID:21602797

  7. Modular Insulators: Genome Wide Search for Composite CTCF/Thyroid Hormone Receptor Binding Sites

    PubMed Central

    Weth, Oliver; Weth, Christine; Bartkuhn, Marek; Leers, Joerg; Uhle, Florian; Renkawitz, Rainer

    2010-01-01

    The conserved 11 zinc-finger protein CTCF is involved in several transcriptional mechanisms, including insulation and enhancer blocking. We had previously identified two composite elements consisting of a CTCF and a TR binding site at the chicken lysozyme and the human c-myc genes. Using these it has been demonstrated that thyroid hormone mediates the relief of enhancer blocking even though CTCF remains bound to its binding site. Here we wished to determine whether CTCF and TR combined sites are representative of a general feature of the genome, and whether such sites are functional in regulating enhancer blocking. Genome wide analysis revealed that about 18% of the CTCF regions harbored at least one of the four different palindromic or repeated sequence arrangements typical for the binding of TR homodimers or TR/RXR heterodimers. Functional analysis of 10 different composite elements of thyroid hormone responsive genes was performed using episomal constructs. The episomal system allowed recapitulating CTCF mediated enhancer blocking function to be dependent on poly (ADP)-ribose modification and to mediate histone deacetylation. Furthermore, thyroid hormone sensitive enhancer blocking could be shown for one of these new composite elements. Remarkably, not only did the regulation of enhancer blocking require functional TR binding, but also the basal enhancer blocking activity of CTCF was dependent on the binding of the unliganded TR. Thus, a number of composite CTCF/TR binding sites may represent a subset of other modular CTCF composite sites, such as groups of multiple CTCF sites or of CTCF/Oct4, CTCF/Kaiso or CTCF/Yy1 combinations. PMID:20404925

  8. A genome-wide search for genes predisposing to manic-depression, assuming autosomal dominant inheritance

    SciTech Connect

    Coon, H.; Jensen, S.; Hoff, M.; Holik, J.; Plaetke, R.; Reimherr, F.; Wender, P.; Leppert, M.; Byerley, W. )

    1993-06-01

    Manic-depressive illness (MDI), also known as [open quotes]bipolar affective disorder[close quotes], is a common and devastating neuropsychiatric illness. Although pivotal biochemical alterations underlying the disease are unknown, results of family, twin, and adoption studies consistently implicate genetic transmission in the pathogenesis of MDI. In order to carry out linkage analysis, the authors ascertained eight moderately sized pedigrees containing multiple cases of the disease. For a four-allele marker mapping at 5 cM from the disease gene, the pedigree sample has >97% power to detect a dominant allele under genetic homogeneity and has >73% power under 20% heterogeneity. To date, the eight pedigrees have been genotyped with 328 polymorphic DNA loci throughout the genome. When autosomal dominant inheritance was assumed, 273 DNA markers gave lod scores <[minus]2.0 at [theta] = .05, and 4 DNA marker loci yielded lod scores >1 (chromosome 5 -- D5S39, D5S43, and D5S62; chromosome 11 -- D11S85). Of the markers giving lod scores >1, only D5S62 continued to show evidence for linkage when the affected-pedigree-member method was used. The D5S62 locus maps to distal 5q, a region containing neurotransmitter-receptor genes for dopamine, norepinephrine, glutamate, and gamma-aminobutyric acid. Although additional work in this region may be warranted, the linkage results should be interpreted as preliminary data, as 68 unaffected individuals are not past the age of risk. 72 refs., 2 tabs.

  9. A genome-wide linkage and association scan reveals novel loci for hypertension and blood pressure traits.

    PubMed

    Guo, Youling; Tomlinson, Brian; Chu, Tanya; Fang, Yu Jing; Gui, Hongsheng; Tang, Clara S; Yip, Benjamin H; Cherny, Stacey S; Hur, Yoon-Mi; Sham, Pak Chung; Lam, Tai Hing; Thomas, Neil G

    2012-01-01

    Hypertension is caused by the interaction of environmental and genetic factors. The condition which is very common, with about 18% of the adult Hong Kong Chinese population and over 50% of older individuals affected, is responsible for considerable morbidity and mortality. To identify genes influencing hypertension and blood pressure, we conducted a combined linkage and association study using over 500,000 single nucleotide polymorphisms (SNPs) genotyped in 328 individuals comprising 111 hypertensive probands and their siblings. Using a family-based association test, we found an association with SNPs on chromosome 5q31.1 (rs6596140; P<9 × 10(-8)) for hypertension. One candidate gene, PDC, was replicated, with rs3817586 on 1q31.1 attaining P = 2.5 × 10(-4) and 2.9 × 10(-5) in the within-family tests for DBP and MAP, respectively. We also identified regions of significant linkage for systolic and diastolic blood pressure on chromosomes 2q22 and 5p13, respectively. Further family-based association analysis of the linkage peak on chromosome 5 yielded a significant association (rs1605685, P<7 × 10(-5)) for DBP. This is the first combined linkage and association study of hypertension and its related quantitative traits with Chinese ancestry. The associations reported here account for the action of common variants whereas the discovery of linkage regions may point to novel targets for rare variant screening.

  10. A genome-wide quantitative trait locus (QTL) linkage scan of NEO personality factors in Latino families segregating bipolar disorder.

    PubMed

    Lee, Byung Dae; Gonzalez, Suzanne; Villa, Erika; Camarillo, Cynthia; Rodriguez, Marco; Yao, Yin; Guo, Wei; Flores, Deborah; Jerez, Alvaro; Raventos, Henriette; Ontiveros, Alfonso; Nicolini, Humberto; Escamilla, Michael

    2017-10-01

    Personality traits have been suggested as potential endophenotypes for Bipolar Disorder (BP), as they can be quantitatively measured and show correlations with BP. The present study utilized data from 2,745 individuals from 686 extended pedigrees originally ascertained for having multiplex cases of BP (963 cases of BPI or schizoaffective BP). Subjects were assessed with the NEO Personality Inventory, Revised (NEO PI-R) and genotyped using the Illumina HumanLinkage-24 Bead Chip, with an average genetic coverage of 0.67 cM. Two point linkage scores were calculated for each trait as a quantitative variable using SOLAR (Sequential Oligogenic Linkage Analysis Routines). Suggestive evidence for linkage was found for neuroticism at 1q32.1 (LOD = 2.52), 6q23.3 (2.32), 16p12 (2.79), extraversion at 4p15.3 (2.33), agreeableness at 4q31.1 (2.37), 5q34 (2.80), 7q31.1 (2.56), 16q22 (2.52), and conscientiousness at 4q31.1 (2.50). Each of the above traits have been shown to be correlated with the broad BP phenotype in this same sample. In addition, for the trait of openness, we found significant evidence of linkage to chromosome 3p24.3 (rs336610, LOD = 4.75) and suggestive evidence at 1q43 (2.74), 5q35.1 (3.03), 11q14.3 (2.61), 11q21 (2.30), and 19q13.1 (2.52). These findings support previous linkage findings of the openness trait to chromosome 19q13 and the agreeableness trait to 4q31 and identify a number of new loci for personality endophenotypes related to bipolar disorder. © 2017 Wiley Periodicals, Inc.

  11. First-generation linkage map of the gray, short-tailed opossum, Monodelphis domestica, reveals genome-wide reduction in female recombination rates.

    PubMed Central

    Samollow, Paul B; Kammerer, Candace M; Mahaney, Susan M; Schneider, Jennifer L; Westenberger, Scott J; VandeBerg, John L; Robinson, Edward S

    2004-01-01

    The gray, short-tailed opossum, Monodelphis domestica, is the most extensively used, laboratory-bred marsupial resource for basic biologic and biomedical research worldwide. To enhance the research utility of this species, we are building a linkage map, using both anonymous markers and functional gene loci, that will enable the localization of quantitative trait loci (QTL) and provide comparative information regarding the evolution of mammalian and other vertebrate genomes. The current map is composed of 83 loci distributed among eight autosomal linkage groups and the X chromosome. The autosomal linkage groups appear to encompass a very large portion of the genome, yet span a sex-average distance of only 633.0 cM, making this the most compact linkage map known among vertebrates. Most surprising, the male map is much larger than the female map (884.6 cM vs. 443.1 cM), a pattern contrary to that in eutherian mammals and other vertebrates. The finding of genome-wide reduction in female recombination in M. domestica, coupled with recombination data from two other, distantly related marsupial species, suggests that reduced female recombination might be a widespread metatherian attribute. We discuss possible explanations for reduced female recombination in marsupials as a consequence of the metatherian characteristic of determinate paternal X chromosome inactivation. PMID:15020427

  12. A consensus framework map of durum wheat (Triticum durum Desf.) suitable for linkage disequilibrium analysis and genome-wide association mapping.

    PubMed

    Maccaferri, Marco; Cane', Maria Angela; Sanguineti, Maria C; Salvi, Silvio; Colalongo, Maria C; Massi, Andrea; Clarke, Fran; Knox, Ron; Pozniak, Curtis J; Clarke, John M; Fahima, Tzion; Dubcovsky, Jorge; Xu, Steven; Ammar, Karim; Karsai, Ildikó; Vida, Gyula; Tuberosa, Roberto

    2014-10-07

    Durum wheat (Triticum durum Desf.) is a tetraploid cereal grown in the medium to low-precipitation areas of the Mediterranean Basin, North America and South-West Asia. Genomics applications in durum wheat have the potential to boost exploitation of genetic resources and to advance understanding of the genetics of important complex traits (e.g. resilience to environmental and biotic stresses). A dense and accurate consensus map specific for T. durum will greatly facilitate genetic mapping, functional genomics and marker-assisted improvement. High quality genotypic data from six core recombinant inbred line populations were used to obtain a consensus framework map of 598 simple sequence repeats (SSR) and Diversity Array Technology® (DArT) anchor markers (common across populations). Interpolation of unique markers from 14 maps allowed us to position a total of 2,575 markers in a consensus map of 2,463 cM. The T. durum A and B genomes were covered in their near totality based on the reference SSR hexaploid wheat map. The consensus locus order compared to those of the single component maps showed good correspondence, (average Spearman's rank correlation rho ρ value of 0.96). Differences in marker order and local recombination rate were observed between the durum and hexaploid wheat consensus maps. The consensus map was used to carry out a whole-genome search for genetic differentiation signatures and association to heading date in a panel of 183 accessions adapted to the Mediterranean areas. Linkage disequilibrium was found to decay below the r2 threshold=0.3 within 2.20 cM, on average. Strong molecular differentiations among sub-populations were mapped to 87 chromosome regions. A genome-wide association scan for heading date from 27 field trials in the Mediterranean Basin and in Mexico yielded 50 chromosome regions with evidences of association in multiple environments. The consensus map presented here was used as a reference for genetic diversity and mapping

  13. Exome Sequencing and Genome-Wide Linkage Analysis in 17 Families Illustrates the Complex Contribution of TTN Truncating Variants to Dilated Cardiomyopathy

    PubMed Central

    Norton, Nadine; Li, Duanxiang; Rampersaud, Evadnie; Morales, Ana; Martin, Eden R.; Zuchner, Stephan; Guo, Shengru; Gonzalez, Michael; Hedges, Dale J.; Robertson, Peggy D.; Krumm, Niklas; Nickerson, Deborah A.; Hershberger, Ray E.

    2013-01-01

    Background Familial dilated cardiomyopathy is a genetically heterogeneous disease with >30 known genes. TTN truncating variants were recently implicated in a candidate gene study to cause 25% of familial and 18% of sporadic dilated cardiomyopathy (DCM) cases. Methods and Results We used an unbiased genome-wide approach employing both linkage analysis and variant filtering across the exome sequences of 48 individuals affected with DCM from 17 families to identify genetic cause. Linkage analysis ranked the TTN region as falling under the second highest genome-wide multipoint linkage peak, MLOD 1.59. We identified six TTN truncating variants carried by affected with DCM in 7 of 17 DCM families (LOD 2.99); 2 of these 7 families also had novel missense variants segregated with disease. Two additional novel truncating TTN variants did not segregate with DCM. Nucleotide diversity at the TTN locus, including missense variants, was comparable to five other known DCM genes. The average number of missense variants in the exome sequences from the DCM cases or the ~5,400 cases from the Exome Sequencing Project was ~23 per individual. The average number of TTN truncating variants in the Exome Sequencing Project was 0.014 per individual. We also identified a region (chr9q21.11-q22.31) with no known DCM genes with a maximum heterogeneity LOD score of 1.74. Conclusions These data suggest that TTN truncating variants contribute to DCM cause. However, the lack of segregation of all identified TTN truncating variants illustrates the challenge of determining variant pathogenicity even with full exome sequencing. PMID:23418287

  14. Exome sequencing and genome-wide linkage analysis in 17 families illustrate the complex contribution of TTN truncating variants to dilated cardiomyopathy.

    PubMed

    Norton, Nadine; Li, Duanxiang; Rampersaud, Evadnie; Morales, Ana; Martin, Eden R; Zuchner, Stephan; Guo, Shengru; Gonzalez, Michael; Hedges, Dale J; Robertson, Peggy D; Krumm, Niklas; Nickerson, Deborah A; Hershberger, Ray E

    2013-04-01

    BACKGROUND- Familial dilated cardiomyopathy (DCM) is a genetically heterogeneous disease with >30 known genes. TTN truncating variants were recently implicated in a candidate gene study to cause 25% of familial and 18% of sporadic DCM cases. METHODS AND RESULTS- We used an unbiased genome-wide approach using both linkage analysis and variant filtering across the exome sequences of 48 individuals affected with DCM from 17 families to identify genetic cause. Linkage analysis ranked the TTN region as falling under the second highest genome-wide multipoint linkage peak, multipoint logarithm of odds, 1.59. We identified 6 TTN truncating variants carried by individuals affected with DCM in 7 of 17 DCM families (logarithm of odds, 2.99); 2 of these 7 families also had novel missense variants that segregated with disease. Two additional novel truncating TTN variants did not segregate with DCM. Nucleotide diversity at the TTN locus, including missense variants, was comparable with 5 other known DCM genes. The average number of missense variants in the exome sequences from the DCM cases or the ≈5400 cases from the Exome Sequencing Project was ≈23 per individual. The average number of TTN truncating variants in the Exome Sequencing Project was 0.014 per individual. We also identified a region (chr9q21.11-q22.31) with no known DCM genes with a maximum heterogeneity logarithm of odds score of 1.74. CONCLUSIONS- These data suggest that TTN truncating variants contribute to DCM cause. However, the lack of segregation of all identified TTN truncating variants illustrates the challenge of determining variant pathogenicity even with full exome sequencing.

  15. Genome-wide linkage analysis of hemodynamic parameters under mental and physical stress in extended Omani Arab pedigrees: the Oman Family Study.

    PubMed

    Hassan, Mohammed O; Jaju, Deepali; Voruganti, V Saroja; Bayoumi, Riad A; Albarwani, Sulayma; Al-Yahyaee, Saeed; Aslani, Afshin; Snieder, Harold; Lopez-Alvarenga, Juan C; Al-Anqoudi, Zahir M; Alizadeh, Behrooz Z; Comuzzie, Anthony G

    2011-06-01

    We performed a genome-wide scan in a homogeneous Arab population to identify genomic regions linked to blood pressure (BP) and its intermediate phenotypes during mental and physical stress tests. The Oman Family Study subjects (N = 1277) were recruited from five extended families of ~10 generations. Hemodynamic phenotypes were computed from beat-to-beat BP, electrocardiography and impedance cardiography. Multi-point linkage was performed for resting, mental (word conflict test, WCT) and cold pressor (CPT) stress and their reactivity scores (s), using variance components decomposition-based methods implemented in SOLAR. Genome-wide scans for BP phenotypes identified quantitative trait loci (QTLs) with significant evidence of linkage on chromosomes 1 and 12 for WCT-linked cardiac output (LOD = 3.1) and systolic BP (LOD = 3.5). Evidence for suggestive linkage for WCT was found on chromosomes 3, 17 and 1 for heart rate (LOD = 2.3), DBP (LOD = 2.4) and left ventricular ejection time (LVET), respectively. For △WCT, suggestive QTLs were detected for CO on chr11 (LOD = 2.5), LVET on chr3 (LOD = 2.0) and EDI on chr9 (LOD = 2.1). For CPT, suggestive QTLs for HR and LVET shared the same region on chr22 (LOD 2.3 and 2.8, respectively) and on chr9 (LOD = 2.3) for SBP, chr7 (LOD = 2.4) for SV and chr19 (LOD = 2.6) for CO. For △CPT, CO and TPR top signals were detected on chr15 and 10 (LOD; 2.40, 2.08) respectively. Mental stress revealed the largest number of significant and suggestive loci for normal BP reported to date. The study of BP and its intermediate phenotypes under mental and physical stress may help reveal the genes involved in the pathogenesis of essential hypertension.

  16. Commonality of functional annotation: a method for prioritization of candidate genes from genome-wide linkage studies†

    PubMed Central

    Shriner, Daniel; Baye, Tesfaye M.; Padilla, Miguel A.; Zhang, Shiju; Vaughan, Laura K.; Loraine, Ann E.

    2008-01-01

    Linkage studies of complex traits frequently yield multiple linkage regions covering hundreds of genes. Testing each candidate gene from every region is prohibitively expensive and computational methods that simplify this process would benefit genetic research. We present a new method based on commonality of functional annotation (CFA) that aids dissection of complex traits for which multiple causal genes act in a single pathway or process. CFA works by testing individual Gene Ontology (GO) terms for enrichment among candidate gene pools, performs multiple hypothesis testing adjustment using an estimate of independent tests based on correlation of GO terms, and then scores and ranks genes annotated with significantly-enriched terms based on the number of quantitative trait loci regions in which genes bearing those annotations appear. We evaluate CFA using simulated linkage data and show that CFA has good power despite being conservative. We apply CFA to published linkage studies investigating age-of-onset of Alzheimer's disease and body mass index and obtain previously known and new candidate genes. CFA provides a new tool for studies in which causal genes are expected to participate in a common pathway or process and can easily be extended to utilize annotation schemes in addition to the GO. PMID:18263617

  17. A Genome-Wide SNP Linkage Analysis Suggests a Susceptibility Locus on 6p21 for Ankylosing Spondylitis and Inflammatory Back Pain Trait

    PubMed Central

    Zhang, Yanli; Liao, Zetao; Wei, Qiujing; Pan, Yunfeng; Wang, Xinwei; Cao, Shuangyan; Guo, Zishi; Wu, Yuqiong; Rong, Ju; Jin, Ou; Xu, Manlong; Gu, Jieruo

    2016-01-01

    Objectives To screen susceptibility loci for ankylosing spondylitis (AS) using an affected-only linkage analysis based on high-density single nucleotide polymorphisms (SNPs) in a genome-wide manner. Patients and Methods AS patients from ten families with Cantonese origin of China were enrolled in the study. Blood samples were genotyped using genomic DNA derived from peripheral blood leukocytes by Illumina HumanHap 610-Quad SNP Chip. Genotype data were generated using the Illumina BeadStudio 3.2 software. PLINK package was used to remove non-autosomal SNPs and to further eliminate markers of typing errors. An affected-only linkage analysis was carried out using both non-parametric and parametric linkage analyses, as implemented in MERLIN. Result Seventy-eight AS patients (48 males and 30 females, mean age: 39±16 years) were enrolled in the study. The mean age of onset was 23±10 years and mean duration of disease was 16.7±12.2 years. Iritis (2/76, 2.86%), dactylitis (5/78, 6.41%), hip joint involvement (9/78, 11.54%), peripheral arthritis (22/78, 28.21%), inflammatory back pain (IBP) (69/78, 88.46%) and HLA-B27 positivity (70/78, 89.74%) were observed in these patients. Using non-parameter linkage analysis, we found one susceptibility locus for AS, IBP and HLA-B27 in 6p21 respectively, spanning about 13.5Mb, 20.9Mb and 21.2Mb, respectively No significant results were found in the other clinical trait groups including dactylitis, hip involved and arthritis. The identical susceptibility locus region spanning above 9.44Mb was detected in AS IBP and HLA-B27 by the parametric linkage analysis. Conclusion Our genome-wide SNP linkage analysis in ten families with ankylosing spondylitis suggests a susceptibility locus on 6p21 in AS, which is a risk locus for IBP in AS patients. PMID:27973620

  18. Genome-wide linkage and positional association analyses identify associations of novel AFF3 and NTM genes with triglycerides: the GenSalt study.

    PubMed

    Li, Changwei; Bazzano, Lydia A L; Rao, Dabeeru C; Hixson, James E; He, Jiang; Gu, Dongfeng; Gu, Charles C; Shimmin, Lawrence C; Jaquish, Cashell E; Schwander, Karen; Liu, De-Pei; Huang, Jianfeng; Lu, Fanghong; Cao, Jie; Chong, Shen; Lu, Xiangfeng; Kelly, Tanika N

    2015-03-20

    We conducted a genome-wide linkage scan and positional association study to identify genes and variants influencing blood lipid levels among participants of the Genetic Epidemiology Network of Salt-Sensitivity (GenSalt) study. The GenSalt study was conducted among 1906 participants from 633 Han Chinese families. Lipids were measured from overnight fasting blood samples using standard methods. Multipoint quantitative trait genome-wide linkage scans were performed on the high-density lipoprotein, low-density lipoprotein, and log-transformed triglyceride phenotypes. Using dense panels of single nucleotide polymorphisms (SNPs), single-marker and gene-based association analyses were conducted to follow-up on promising linkage signals. Additive associations between each SNP and lipid phenotypes were tested using mixed linear regression models. Gene-based analyses were performed by combining P-values from single-marker analyses within each gene using the truncated product method (TPM). Significant associations were assessed for replication among 777 Asian participants of the Multi-ethnic Study of Atherosclerosis (MESA). Bonferroni correction was used to adjust for multiple testing. In the GenSalt study, suggestive linkage signals were identified at 2p11.2‒2q12.1 [maximum multipoint LOD score (MML) = 2.18 at 2q11.2] and 11q24.3‒11q25 (MML = 2.29 at 11q25) for the log-transformed triglyceride phenotype. Follow-up analyses of these two regions revealed gene-based associations of charged multivesicular body protein 3 (CHMP3), ring finger protein 103 (RNF103), AF4/FMR2 family, member 3 (AFF3), and neurotrimin (NTM) with triglycerides (P = 4 × 10(-4), 1.00 × 10(-5), 2.00 × 10(-5), and 1.00 × 10(-7), respectively). Both the AFF3 and NTM triglyceride associations were replicated among MESA study participants (P = 1.00 × 10(-7) and 8.00 × 10(-5), respectively). Furthermore, NTM explained the linkage signal on chromosome 11. In conclusion, we identified novel genes

  19. Genome-Wide Linkage and Positional Association Analyses Identify Associations of Novel AFF3 and NTM Genes with Triglycerides: The GenSalt Study

    PubMed Central

    Li, Changwei; Bazzano, Lydia A.L.; Rao, Dabeeru C.; Hixson, James E.; He, Jiang; Gu, Dongfeng; Gu, Charles C.; Shimmin, Lawrence C.; Jaquish, Cashell E.; Schwander, Karen; Liu, De-Pei; Huang, Jianfeng; Lu, Fanghong; Cao, Jie; Chong, Shen; Lu, Xiangfeng; Kelly, Tanika N.

    2016-01-01

    We conducted a genome-wide linkage scan and positional association study to identify genes and variants influencing blood lipid levels among participants of the Genetic Epidemiology Network of Salt-Sensitivity (GenSalt) study. The GenSalt study was conducted among 1906 participants from 633 Han Chinese families. Lipids were measured from overnight fasting blood samples using standard methods. Multipoint quantitative trait genome-wide linkage scans were performed on the high-density lipoprotein, low-density lipoprotein, and log-transformed triglyceride phenotypes. Using dense panels of single nucleotide polymorphisms (SNPs), single-marker and gene-based association analyses were conducted to follow-up on promising linkage signals. Additive associations between each SNP and lipid phenotypes were tested using mixed linear regression models. Gene-based analyses were performed by combining P-values from single-marker analyses within each gene using the truncated product method (TPM). Significant associations were assessed for replication among 777 Asian participants of the Multi-ethnic Study of Atherosclerosis (MESA). Bonferroni correction was used to adjust for multiple testing. In the GenSalt study, suggestive linkage signals were identified at 2p11.2–2q12.1 [maximum multipoint LOD score (MML) = 2.18 at 2q11.2] and 11q24.3–11q25 (MML = 2.29 at 11q25) for the log-transformed triglyceride phenotype. Follow-up analyses of these two regions revealed gene-based associations of charged multivesicular body protein 3 (CHMP3), ring finger protein 103 (RNF103), AF4/FMR2 family, member 3 (AFF3), and neurotrimin (NTM ) with triglycerides (P = 4 × 10−4, 1.00 × 10−5, 2.00 × 10−5, and 1.00 × 10−7, respectively). Both the AFF3 and NTM triglyceride associations were replicated among MESA study participants (P = 1.00 × 10−7 and 8.00 × 10−5, respectively). Furthermore, NTM explained the linkage signal on chromosome 11. In conclusion, we identified novel genes

  20. Multigenic Control of Pod Shattering Resistance in Chinese Rapeseed Germplasm Revealed by Genome-Wide Association and Linkage Analyses

    PubMed Central

    Liu, Jia; Wang, Jun; Wang, Hui; Wang, Wenxiang; Zhou, Rijin; Mei, Desheng; Cheng, Hongtao; Yang, Juan; Raman, Harsh; Hu, Qiong

    2016-01-01

    The majority of rapeseed cultivars shatter seeds upon maturity especially under hot-dry and windy conditions, reducing yield and gross margin return to growers. Here, we identified quantitative trait loci (QTL) for resistance to pod shatter in an unstructured diverse panel of 143 rapeseed accessions, and two structured populations derived from bi-parental doubled haploid (DH) and inter-mated (IF2) crosses derived from R1 (resistant to pod shattering) and R2 (prone to pod shattering) accessions. Genome-wide association analysis identified six significant QTL for resistance to pod shatter located on chromosomes A01, A06, A07, A09, C02, and C05. Two of the QTL, qSRI.A09 delimited with the SNP marker Bn-A09-p30171993 (A09) and qSRI.A06 delimited with the SNP marker Bn-A06-p115948 (A06) could be repeatedly detected across environments in a diversity panel, DH and IF2 populations, suggesting that at least two loci on chromosomes A06 and A09 were the main contributors to pod shatter resistance in Chinese germplasm. Significant SNP markers identified in this study especially those that appeared repeatedly across environments provide a cost-effective and an efficient method for introgression and pyramiding of favorable alleles for pod shatter resistance via marker-assisted selection in rapeseed improvement programs. PMID:27493651

  1. Chromosomes 4 and 8 Implicated in a Genome Wide SNP Linkage Scan of 762 Prostate Cancer Families Collected by the ICPCG

    PubMed Central

    Lu, Lingyi; Cancel-Tassin, Geraldine; Valeri, Antoine; Cussenot, Olivier; Lange, Ethan M.; Cooney, Kathleen A.; Farnham, James M.; Camp, Nicola J.; Cannon-Albright, Lisa A.; Tammela, Teuvo L.J.; Schleutker, Johanna; Hoegel, Josef; Herkommer, Kathleen; Maier, Christiane; Vogel, Walther; Wiklund, Fredrik; Emanuelsson, Monica; Grönberg, Henrik; Wiley, Kathleen E.; Isaacs, Sarah D.; Walsh, Patrick C.; Helfand, Brian T.; Kan, Donghui; Catalona, William J.; Stanford, Janet L.; FitzGerald, Liesel M.; Johanneson, Bo; Deutsch, Kerry; McIntosh, Laura; Ostrander, Elaine A.; Thibodeau, Stephen N.; McDonnell, Shannon K.; Hebbring, Scott; Schaid, Daniel J.; Whittemore, Alice S.; Oakley-Girvan, Ingrid; Hsieh, Chih-Lin; Powell, Isaac; Bailey-Wilson, Joan E.; Carpten, John D.; Seminara, Daniela; Zheng, S. Lilly; Xu, Jianfeng; Giles, Graham G.; Severi, Gianluca; Hopper, John L.; English, Dallas R.; Foulkes, William D.; Maehle, Lovise; Moller, Pal; Badzioch, Michael D.; Edwards, Steve; Guy, Michelle; Eeles, Ros; Easton, Douglas; Isaacs, William B.

    2012-01-01

    Background In spite of intensive efforts, understanding of the genetic aspects of familial prostate cancer remains largely incomplete. In a previous microsatellite-based linkage scan of 1233 prostate cancer (PC) families, we identified suggestive evidence for linkage (i.e. LOD≥1.86) at 5q12, 15q11, 17q21, 22q12, and two loci on 8p, with additional regions implicated in subsets of families defined by age at diagnosis, disease aggressiveness, or number of affected members. Methods In an attempt to replicate these findings and increase linkage resolution, we used the Illumina 6000 SNP linkage panel to perform a genome-wide linkage scan of an independent set of 762 multiplex PC families, collected by 11 ICPCG groups. Results Of the regions identified previously, modest evidence of replication was observed only on the short arm of chromosome 8, where HLOD scores of 1.63 and 3.60 were observed in the complete set of families and families with young average age at diagnosis, respectively. The most significant linkage signals found in the complete set of families were observed across a broad, 37 cM interval on 4q13-25, with LOD scores ranging from 2.02 to 2.62, increasing to 4.50 in families with older average age at diagnosis. In families with multiple cases presenting with more aggressive disease, LOD scores over 3.0 were observed at 8q24 in the vicinity of previously identified common PC risk variants, as well as MYC, an important gene in PC biology. Conclusions These results will be useful in prioritizing future susceptibility gene discovery efforts in this common cancer. PMID:21748754

  2. Genome-Wide Linkage and Regional Association Study of Blood Pressure Response to the Cold Pressor Test in Han Chinese: The GenSalt Study

    PubMed Central

    Yang, Xueli; Gu, Dongfeng; He, Jiang; Hixson, James E.; Rao, Dabeeru C.; Lu, Fanghong; Mu, Jianjun; Jaquish, Cashell E.; Chen, Jing; Huang, Jianfeng; Shimmin, Lawrence C.; Rice, Treva K.; Chen, Jichun; Wu, Xigui; Liu, Depei; Kelly, Tanika N.

    2014-01-01

    Background Blood pressure (BP) response to cold pressor test (CPT) is associated with increased risk of cardiovascular disease. We performed a genome-wide linkage scan and regional association analysis to identify genetic determinants of BP response to CPT. Methods and Results A total of 1,961 Chinese participants completed the CPT. Multipoint quantitative trait linkage analysis was performed, followed by single-marker and gene-based analyses of variants in promising linkage regions (logarithm of odds, LOD ≥ 2). A suggestive linkage signal was identified for systolic BP (SBP) response to CPT at 20p13-20p12.3, with a maximum multipoint LOD score of 2.37. Based on regional association analysis with 1,351 SNPs in the linkage region, we found that marker rs2326373 at 20p13 was significantly associated with mean arterial pressure (MAP) responses to CPT (P = 8.8×10−6) after FDR adjustment for multiple comparisons. A similar trend was also observed for SBP response (P = 0.03) and DBP response (P = 4.6×10−5). Results of gene-based analyses showed that variants in genes MCM8 and SLC23A2 were associated with SBP response to CPT (P = 4.0×10−5 and 2.7×10−4, respectively), and variants in genes MCM8 and STK35 were associated with MAP response to CPT (P = 1.5×10−5 and 5.0×10−5, respectively). Conclusions Within a suggestive linkage region on chromosome 20, we identified a novel variant associated with BP responses to CPT. We also found gene-based associations of MCM8, SLC23A2 and STK35 in this region. Further work is warranted to confirm these findings. Clinical Trial Registration URL: http://www.clinicaltrials.gov; Unique identifier: NCT00721721. PMID:25028485

  3. Genome-wide linkage scan in a large bipolar disorder sample from the National Institute of Mental Health genetics initiative suggests putative loci for bipolar disorder, psychosis, suicide, and panic disorder.

    PubMed

    Cheng, R; Juo, S H; Loth, J E; Nee, J; Iossifov, I; Blumenthal, R; Sharpe, L; Kanyas, K; Lerer, B; Lilliston, B; Smith, M; Trautman, K; Gilliam, T C; Endicott, J; Baron, M

    2006-03-01

    We conducted a 9-cM genome scan in a large bipolar pedigree sample from the National Institute of Mental Health genetics initiative (1060 individuals from 154 multiplex families). We performed parametric and nonparametric analyses using both standard diagnostic models and comorbid conditions thought to identify phenotypic subtypes: psychosis, suicidal behavior, and panic disorder. Our strongest linkage signals (genome-wide significance) were observed on chromosomes 10q25, 10p12, 16q24, 16p13, and 16p12 using standard diagnostic models, and on 6q25 (suicidal behavior), 7q21 (panic disorder) and 16p12 (psychosis) using phenotypic subtypes. Several other regions were suggestive of linkage, including 1p13 (psychosis), 1p21 (psychosis), 1q44, 2q24 (suicidal behavior), 2p25 (psychosis), 4p16 (psychosis, suicidal behavior), 5p15, 6p25 (psychosis), 8p22 (psychosis), 8q24, 10q21, 10q25 (suicidal behavior), 10p11 (psychosis), 13q32 and 19p13 (psychosis). Over half the implicated regions were identified using phenotypic subtypes. Several regions - 1p, 1q, 6q, 8p, 13q and 16p - have been previously reported to be linked to bipolar disorder. Our results suggest that dissection of the disease phenotype can enrich the harvest of linkage signals and expedite the search for susceptibility genes. This is the first large-scale linkage scan of bipolar disorder to analyze simultaneously bipolar disorder, psychosis, suicidal behavior, and panic disorder.

  4. Genome-wide SNP identification, linkage map construction and QTL mapping for seed mineral concentrations and contents in pea (Pisum sativum L.).

    PubMed

    Ma, Yu; Coyne, Clarice J; Grusak, Michael A; Mazourek, Michael; Cheng, Peng; Main, Dorrie; McGee, Rebecca J

    2017-02-13

    Marker-assisted breeding is now routinely used in major crops to facilitate more efficient cultivar improvement. This has been significantly enabled by the use of next-generation sequencing technology to identify loci and markers associated with traits of interest. While rich in a range of nutritional components, such as protein, mineral nutrients, carbohydrates and several vitamins, pea (Pisum sativum L.), one of the oldest domesticated crops in the world, remains behind many other crops in the availability of genomic and genetic resources. To further improve mineral nutrient levels in pea seeds requires the development of genome-wide tools. The objectives of this research were to develop these tools by: identifying genome-wide single nucleotide polymorphisms (SNPs) using genotyping by sequencing (GBS); constructing a high-density linkage map and comparative maps with other legumes, and identifying quantitative trait loci (QTL) for levels of boron, calcium, iron, potassium, magnesium, manganese, molybdenum, phosphorous, sulfur, and zinc in the seed, as well as for seed weight. In this study, 1609 high quality SNPs were found to be polymorphic between 'Kiflica' and 'Aragorn', two parents of an F6-derived recombinant inbred line (RIL) population. Mapping 1683 markers including 75 previously published markers and 1608 SNPs developed from the present study generated a linkage map of size 1310.1 cM. Comparative mapping with other legumes demonstrated that the highest level of synteny was observed between pea and the genome of Medicago truncatula. QTL analysis of the RIL population across two locations revealed at least one QTL for each of the mineral nutrient traits. In total, 46 seed mineral concentration QTLs, 37 seed mineral content QTLs, and 6 seed weight QTLs were discovered. The QTLs explained from 2.4% to 43.3% of the phenotypic variance. The genome-wide SNPs and the genetic linkage map developed in this study permitted QTL identification for pea seed mineral

  5. A Genome-Wide Scan for Loci Influencing Adolescent Cannabis Dependence Symptoms: Evidence for Linkage on Chromosomes 3 and 9

    PubMed Central

    Hopfer, Christian J.; Lessem, Jeffrey M.; Hartman, Christie A.; Stallings, Michael C.; Cherny, Stacey S.; Corley, Robin P.; Hewitt, John K.; Krauter, Kenneth S.; Mikulich-Gilbertson, Susan K.; Rhee, Soo Hyun; Smolen, Andrew; Young, Susan E.; Crowley, Thomas J.

    2007-01-01

    Objective: Cannabis is the most frequently abused illicit substance among adolescents and young adults. Genetic risk factors account for part of the variation in the development of Cannabis Dependence symptoms; however, no linkage studies have been performed for Cannabis Dependence symptoms. This study aimed to identify such loci. Method: 324 sibling pairs from 192 families were assessed for Cannabis Dependence symptoms. Probands (13-19 years of age) were recruited from consecutive admissions to substance abuse treatment facilities. The siblings of the probands ranged in age from 12-25 years. A community-based sample of 4843 adolescents and young adults was utilized to define an age- and sex-corrected index of Cannabis Dependence vulnerability. DSM-IV Cannabis Dependence symptoms were assessed in youth and their family members with the Composite International Diagnostic Instrument -Substance Abuse Module. Siblings and parents were genotyped for 374 microsatellite markers distributed across the 22 autosomes (average inter-marker distance = 9.2 cM). Cannabis Dependence symptoms were analyzed using Merlin-regress, a regression-based method that is robust to sample selection. Results: Evidence for suggestive linkage was found on chromosome 3q21 near marker D3S1267 (LOD = 2.61), and on chromosome 9q34 near marker D9S1826 (LOD = 2.57). Conclusions: This is the first reported linkage study of cannabis dependence symptoms. Other reports of linkage regions for illicit substance dependence have been reported near 3q21, suggesting that this region may contain a quantitative trait loci influencing cannabis dependence and other substance use disorders. PMID:17169504

  6. A genome-wide linkage scan for cleft lip and cleft palate identifies a novel locus on 8p11-23.

    PubMed

    Riley, B M; Schultz, R E; Cooper, M E; Goldstein-McHenry, T; Daack-Hirsch, S; Lee, K T; Dragan, E; Vieira, A R; Lidral, A C; Marazita, M L; Murray, J C

    2007-04-15

    Isolated or nonsyndromic cleft lip and palate (NS CLP) is a complex disorder resulting from multiple genetic and environmental factors. NS CLP has a birth prevalence of 1 per 500 in the Philippines where large families provide an opportunity for gene localization. Genotyping of 392 microsatellite repeat markers at 10 cM intervals over the genome was performed by the Center for Inherited Disease Research (CIDR) on 220 Filipino families with 567 affected and 1,109 unaffected family members genotyped. Among the most statistically significant results from analysis of the genome-wide scan data was a 20 cM region at 8p11-23 in which markers had LODs > or =1.0. This region on 8p11-23 has not been found in any previous genome wide scan nor does it contain any of the candidate genes widely studied in CLP. Fine mapping in 8p11-23 was done in the 220 families plus an additional 51 families, using SNP markers from 10 known genes (FGFR1, NRG1, FZD3, SLC8A1, PPP3CC, EPHX2, BNIP3L, EGR3, PPP2R2A, and NAT1) within the 20 cM region of 8p11-23. Linkage and association analyses of these SNPs yield suggestive results for markers in FGFR1 (recessive multipoint HLOD 1.07) and BAG4 (recessive multipoint HLOD 1.31). Copyright 2007 Wiley-Liss, Inc.

  7. Coordinated Action of Biological Processes during Embryogenesis Can Cause Genome-Wide Linkage Disequilibrium in the Human Genome and Influence Age-Related Phenotypes

    PubMed Central

    Culminskaya, Irina; Kulminski, Alexander M.; Yashin, Anatoli I.

    2017-01-01

    A role of non-Mendelian inheritance in genetics of complex, age-related traits is becoming increasingly recognized. Recently, we reported on two inheritable clusters of SNPs in extensive genome-wide linkage disequilibrium (LD) in the Framingham Heart Study (FHS), which were associated with the phenotype of premature death. Here we address biologically-related properties of these two clusters. These clusters have been unlikely selected randomly because they are functionally and structurally different from matched sets of randomly selected SNPs. For example, SNPs in LD from each cluster are highly significantly enriched in genes (p=7.1×10−22 and p=5.8×10−18), in general, and in short genes (p=1.4×10−47 and p=4.6×10−7), in particular. Mapping of SNPs in LD to genes resulted in two, partly overlapping, networks of 1764 and 4806 genes. Both these networks were gene enriched in developmental processes and in biological processes tightly linked with development including biological adhesion, cellular component organization, locomotion, localization, signaling, (p<10−4, q<10−4 for each category). Thorough analysis suggests connections of these genetic networks with different stages of embryogenesis and highlights biological interlink of specific processes enriched for genes from these networks. The results suggest that coordinated action of biological processes during embryogenesis may generate genome-wide networks of genetic variants, which may influence complex age-related phenotypes characterizing health span and lifespan. PMID:28357417

  8. A Genome-Wide Linkage Scan for Cleft Lip and Cleft Palate Identifies a Novel Locus on 8p11-23

    PubMed Central

    Riley, B.M.; Schultz, R.E.; Cooper, M.E.; Goldstein-McHenry, T.; Daack-Hirsch, S.; Lee, K.T.; Dragan, E.; Vieira, A.R.; Lidral, A.C.; Marazita, M.L.; Murray, J.C.

    2008-01-01

    Isolated or nonsyndromic cleft lip and palate (NS CLP) is a complex disorder resulting from multiple genetic and environmental factors. NS CLP has a birth prevalence of 1 per 500 in the Philippines where large families provide an opportunity for gene localization. Genotyping of 392 microsatellite repeat markers at 10 cM intervals over the genome was performed by the Center for Inherited Disease Research (CIDR) on 220 Filipino families with 567 affected and 1,109 unaffected family members genotyped. Among the most statistically significant results from analysis of the genome-wide scan data was a 20 cM region at 8p11-23 in which markers had LODs ≥1.0. This region on 8p11-23 has not been found in any previous genome wide scan nor does it contain any of the candidate genes widely studied in CLP. Fine mapping in 8p11-23 was done in the 220 families plus an additional 51 families, using SNP markers from 10 known genes (FGFR1, NRG1, FZD3, SLC8A1, PPP3CC, EPHX2, BNIP3L, EGR3, PPP2R2A, and NAT1) within the 20 cM region of 8p11-23. Linkage and association analyses of these SNPs yield suggestive results for markers in FGFR1 (recessive multipoint HLOD 1.07) and BAG4 (recessive multipoint HLOD 1.31). PMID:17366557

  9. Genome-wide scan for serum ghrelin detects linkage on chromosome 1p36 in Hispanic children: results from the Viva La Familia study.

    PubMed

    Voruganti, V Saroja; Göring, Harald H H; Diego, Vincent P; Cai, Guowen; Mehta, Nitesh R; Haack, Karin; Cole, Shelley A; Butte, Nancy F; Comuzzie, Anthony G

    2007-10-01

    This study was conducted to investigate genetic influence on serum ghrelin and its relationship with adiposity-related phenotypes in Hispanic children (n=1030) from the Viva La Familia study (VFS). Anthropometric measurements and levels of serum ghrelin were estimated and genetic analyses conducted according to standard procedures. Mean age, body mass index (BMI), and serum ghrelin were 11+/-0.13 y, 25+/-0.24 kg/m2 and 38+/-0.5 ng/mL, respectively. Significant heritabilities (p<0.001) were obtained for BMI, weight, fat mass, percent fat, waist circumference, waist-to-height ratio, and ghrelin. Bivariate analyses of ghrelin with adiposity traits showed significant negative genetic correlations (p<0.0001) with weight, BMI, fat mass, percent fat, waist circumference, and waist-to-height ratio. A genome-wide scan for ghrelin detected significant linkage on chromosome 1p36.2 between STR markers D1S2697 and D1S199 (LOD=3.2). The same region on chromosome 1 was the site of linkage for insulin (LOD=3.3), insulinlike growth factor binding protein 1 (IGFBP1) (LOD=3.4), homeostatic model assessment method (HOMA) (LOD=2.9), and C-peptide (LOD=2.0). Several family-based studies have reported linkages for obesity-related phenotypes in the region of 1p36. These results indicate the importance of this region in relation to adiposity in children from the VFS.

  10. FHSA-SED: Two-Locus Model Detection for Genome-Wide Association Study with Harmony Search Algorithm.

    PubMed

    Tuo, Shouheng; Zhang, Junying; Yuan, Xiguo; Zhang, Yuanyuan; Liu, Zhaowen

    2016-01-01

    Two-locus model is a typical significant disease model to be identified in genome-wide association study (GWAS). Due to intensive computational burden and diversity of disease models, existing methods have drawbacks on low detection power, high computation cost, and preference for some types of disease models. In this study, two scoring functions (Bayesian network based K2-score and Gini-score) are used for characterizing two SNP locus as a candidate model, the two criteria are adopted simultaneously for improving identification power and tackling the preference problem to disease models. Harmony search algorithm (HSA) is improved for quickly finding the most likely candidate models among all two-locus models, in which a local search algorithm with two-dimensional tabu table is presented to avoid repeatedly evaluating some disease models that have strong marginal effect. Finally G-test statistic is used to further test the candidate models. We investigate our method named FHSA-SED on 82 simulated datasets and a real AMD dataset, and compare it with two typical methods (MACOED and CSE) which have been developed recently based on swarm intelligent search algorithm. The results of simulation experiments indicate that our method outperforms the two compared algorithms in terms of detection power, computation time, evaluation times, sensitivity (TPR), specificity (SPC), positive predictive value (PPV) and accuracy (ACC). Our method has identified two SNPs (rs3775652 and rs10511467) that may be also associated with disease in AMD dataset.

  11. FHSA-SED: Two-Locus Model Detection for Genome-Wide Association Study with Harmony Search Algorithm

    PubMed Central

    Tuo, Shouheng; Zhang, Junying; Yuan, Xiguo; Zhang, Yuanyuan; Liu, Zhaowen

    2016-01-01

    Motivation Two-locus model is a typical significant disease model to be identified in genome-wide association study (GWAS). Due to intensive computational burden and diversity of disease models, existing methods have drawbacks on low detection power, high computation cost, and preference for some types of disease models. Method In this study, two scoring functions (Bayesian network based K2-score and Gini-score) are used for characterizing two SNP locus as a candidate model, the two criteria are adopted simultaneously for improving identification power and tackling the preference problem to disease models. Harmony search algorithm (HSA) is improved for quickly finding the most likely candidate models among all two-locus models, in which a local search algorithm with two-dimensional tabu table is presented to avoid repeatedly evaluating some disease models that have strong marginal effect. Finally G-test statistic is used to further test the candidate models. Results We investigate our method named FHSA-SED on 82 simulated datasets and a real AMD dataset, and compare it with two typical methods (MACOED and CSE) which have been developed recently based on swarm intelligent search algorithm. The results of simulation experiments indicate that our method outperforms the two compared algorithms in terms of detection power, computation time, evaluation times, sensitivity (TPR), specificity (SPC), positive predictive value (PPV) and accuracy (ACC). Our method has identified two SNPs (rs3775652 and rs10511467) that may be also associated with disease in AMD dataset. PMID:27014873

  12. Genome wide linkage study, using a 250K SNP map, of Plasmodium falciparum infection and mild malaria attack in a Senegalese population.

    PubMed

    Milet, Jacqueline; Nuel, Gregory; Watier, Laurence; Courtin, David; Slaoui, Yousri; Senghor, Paul; Migot-Nabias, Florence; Gaye, Oumar; Garcia, André

    2010-07-15

    Multiple factors are involved in the variability of host's response to P. falciparum infection, like the intensity and seasonality of malaria transmission, the virulence of parasite and host characteristics like age or genetic make-up. Although admitted nowadays, the involvement of host genetic factors remains unclear. Discordant results exist, even concerning the best-known malaria resistance genes that determine the structure or function of red blood cells. Here we report on a genome-wide linkage and association study for P. falciparum infection intensity and mild malaria attack among a Senegalese population of children and young adults from 2 to 18 years old. A high density single nucleotide polymorphisms (SNP) genome scan (Affimetrix GeneChip Human Mapping 250K-nsp) was performed for 626 individuals: i.e. 249 parents and 377 children out of the 504 ones included in the follow-up. The population belongs to a unique ethnic group and was closely followed-up during 3 years. Genome-wide linkage analyses were performed on four clinical and parasitological phenotypes and association analyses using the family based association tests (FBAT) method were carried out in regions previously linked to malaria phenotypes in literature and in the regions for which we identified a linkage peak. Analyses revealed three strongly suggestive evidences for linkage: between mild malaria attack and both the 6p25.1 and the 12q22 regions (empirical p-value=5x10(-5) and 9x10(-5) respectively), and between the 20p11q11 region and the prevalence of parasite density in asymptomatic children (empirical p-value=1.5x10(-4)). Family based association analysis pointed out one significant association between the intensity of plasmodial infection and a polymorphism located in ARHGAP26 gene in the 5q31-q33 region (p-value=3.7x10(-5)). This study identified three candidate regions, two of them containing genes that could point out new pathways implicated in the response to malaria infection

  13. Genome Wide Linkage Study, Using a 250K SNP Map, of Plasmodium falciparum Infection and Mild Malaria Attack in a Senegalese Population

    PubMed Central

    Milet, Jacqueline; Nuel, Gregory; Watier, Laurence; Courtin, David; Slaoui, Yousri; Senghor, Paul; Migot-Nabias, Florence; Gaye, Oumar; Garcia, André

    2010-01-01

    Multiple factors are involved in the variability of host's response to P. falciparum infection, like the intensity and seasonality of malaria transmission, the virulence of parasite and host characteristics like age or genetic make-up. Although admitted nowadays, the involvement of host genetic factors remains unclear. Discordant results exist, even concerning the best-known malaria resistance genes that determine the structure or function of red blood cells. Here we report on a genome-wide linkage and association study for P. falciparum infection intensity and mild malaria attack among a Senegalese population of children and young adults from 2 to 18 years old. A high density single nucleotide polymorphisms (SNP) genome scan (Affimetrix GeneChip Human Mapping 250K-nsp) was performed for 626 individuals: i.e. 249 parents and 377 children out of the 504 ones included in the follow-up. The population belongs to a unique ethnic group and was closely followed-up during 3 years. Genome-wide linkage analyses were performed on four clinical and parasitological phenotypes and association analyses using the family based association tests (FBAT) method were carried out in regions previously linked to malaria phenotypes in literature and in the regions for which we identified a linkage peak. Analyses revealed three strongly suggestive evidences for linkage: between mild malaria attack and both the 6p25.1 and the 12q22 regions (empirical p-value = 5×10−5 and 9×10−5 respectively), and between the 20p11q11 region and the prevalence of parasite density in asymptomatic children (empirical p-value = 1.5×10−4). Family based association analysis pointed out one significant association between the intensity of plasmodial infection and a polymorphism located in ARHGAP26 gene in the 5q31–q33 region (p-value = 3.7×10−5). This study identified three candidate regions, two of them containing genes that could point out new pathways implicated in the response to

  14. Two-Stage Genome-Wide Search for Epistasis with Implementation to Recombinant Inbred Lines (RIL) Populations

    PubMed Central

    Goldstein, Pavel; Korol, Abraham B.; Reiner-Benaim, Anat

    2014-01-01

    Objective and Methods This paper proposes an inegrative two-stage genome-wide search for pairwise epistasis on expression quantitative trait loci (eQTL). The traits are clustered into multi-trait complexes that account for correlations between them that may result from common epistasis effects. The search is done by first screening for epistatic regions and then using dense markers within the identified regions, resulting in substantial reduction in the number of tests for epistasis. The FDR is controlled using a hierarchical procedure that accounts for the search structure. Each combination of trait and marker-pair is tested using a model that accounts for both statistical and functional interpretations of epistasis and considers orthogonal effects, such that their contributions to heritability can be estimated individually. We examine the impact of using multi-trait complexes rather than single traits, and of using a hierarchical search for epistasis rather than skipping the initial screen for epistatic regions. We apply the proposed algorithm on Arabidopsis transcription data. Principal Findings Both epistasis detection power and heritability contributed by epistasis increased when using multi-trait complexes rather than single traits. Epistatic effects common to the eQTLs included in the complexes have higher chance of being identified by analysis of multi-trait complexes, particularly when epistatic effects on individual traits are small. Compared to direct testing for all potential epistatic effects, the hierarchical search was substantially more powerful in detecting epistasis, while controlling the FDR at the desired level. Association in functional roles within genomic regions was observed, supporting an initial screen for epistatic QTLs. PMID:25536193

  15. Sex-limited genome-wide linkage scan for body mass index in an unselected sample of 933 Australian twin families.

    PubMed

    Cornes, Belinda K; Medland, Sarah E; Ferreira, Manuel A R; Morley, Katherine I; Duffy, David L; Heijmans, Bastiaan T; Montgomery, Grant W; Martin, Nicholas G

    2005-12-01

    Genes involved in pathways regulating body weight may operate differently in men and women. To determine whether sex-limited genes influence the obesity-related phenotype body mass index (BMI), we have conducted a general nonscalar sex-limited genome-wide linkage scan using variance components analysis in Mx (Neale, 2002). BMI measurements and genotypic data were available for 2053 Australian female and male adult twins and their siblings from 933 families. Clinical measures of BMI were available for 64.4% of these individuals, while only self-reported measures were available for the remaining participants. The mean age of participants was 39.0 years of age (SD 12.1 years). The use of a sex-limited linkage model identified areas on the genome where quantitative trait loci (QTL) effects differ between the sexes, particularly on chromosome 8 and 20, providing us with evidence that some of the genes responsible for BMI may have different effects in men and women. Our highest linkage peak was observed at 12q24 (-log10p = 3.02), which was near the recommended threshold for suggestive linkage (-log10p = 3.13). Previous studies have found evidence for a quantitative trait locus on 12q24 affecting BMI in a wide range of populations, and candidate genes for noninsulin-dependent diabetes mellitus, a consequence of obesity, have also been mapped to this region. We also identified many peaks near a -log10p of 2 (threshold for replicating an existing finding) in many areas across the genome that are within regions previously identified by other studies, as well as in locations that harbor genes known to influence weight regulation.

  16. Genome-wide linkage study suggests a susceptibility locus for isolated bilateral microtia on 4p15.32-4p16.2.

    PubMed

    Li, Xin; Hu, Jintian; Zhang, Jiao; Jin, Qian; Wang, Duen-Mei; Yu, Jun; Zhang, Qingguo; Zhang, Yong-Biao

    2014-01-01

    Microtia is a congenital deformity where the external ear is underdeveloped. Genetic investigations have identified many susceptibility genes of microtia-related syndromes. However, no causal genes were reported for isolated microtia, the main form of microtia. We conducted a genome-wide linkage analysis on a 5-generation Chinese pedigree with isolated bilateral microtia. We identified a suggestive linkage locus on 4p15.32-4p16.2 with parametric LOD score of 2.70 and nonparametric linkage score (Zmean) of 12.28 (simulated occurrence per genome scan equal to 0.46 and 0.47, respectively). Haplotype reconstruction analysis of the 4p15.32-4p16.2 region further confined the linkage signal to a 10-Mb segment located between rs12505562 and rs12649803 (9.65-30.24 cM; 5.54-15.58 Mb). Various human organ developmental genes reside in this 10-Mb susceptibility region, such as EVC, EVC2, SLC2A9, NKX3-2, and HMX1. The coding regions of three genes, EVC known for cartilage development and NKX3-2, HMX1 involved in microtia, were selected for sequencing with 5 individuals from the pedigree. Of the 38 identified sequence variants, none segregates along with the disease phenotype. Other genes or DNA sequences of the 10-Mb region warrant for further investigation. In conclusion, we report a susceptibility locus of isolated microtia, and this finding will encourage future studies on the genetic basis of ear deformity.

  17. Genome-wide linkage analysis of quantitative biomarker traits of osteoarthritis in a large, multigenerational extended family.

    PubMed

    Chen, Hsiang-Cheng; Kraus, Virginia Byers; Li, Yi-Ju; Nelson, Sarah; Haynes, Carol; Johnson, Jessica; Stabler, Thomas; Hauser, Elizabeth R; Gregory, Simon G; Kraus, William E; Shah, Svati H

    2010-03-01

    The genetic contributions to the multifactorial disorder osteoarthritis (OA) have been increasingly recognized. The goal of the current study was to use OA-related biomarkers of severity and disease burden as quantitative traits to identify genetic susceptibility loci for OA. In a large multigenerational extended family (n = 350), we measured 5 OA-related biomarkers: hyaluronan (HA), cartilage oligomeric matrix protein (COMP), N-propeptide of type IIA collagen (PIIANP), C-propeptide of type II procollagen (CPII), and type II collagen neoepitope (C2C). Single-nucleotide polymorphism markers (n = 6,090) covering the whole genome were genotyped using the Illumina HumanLinkage-12 BeadChip. Variance components analysis, as implemented in the Sequential Oligogenic Linkage Analysis Routines, was used to estimate heritabilities of the quantitative traits and to calculate 2-point and multipoint logarithm of odds (LOD) scores using a polygenic model. After adjusting for age and sex, we found that 4 of the 5 biomarkers exhibited significant heritability (PIIANP 0.57, HA 0.49, COMP 0.43, C2C 0.30; P < or = 0.01 for all). Fourteen of the 19 loci that had multipoint LOD scores of >1.5 were near to or overlapped with previously reported OA susceptibility loci. Four of these loci were identified by more than 1 biomarker. The maximum multipoint LOD scores for the heritable quantitative biomarker traits were 4.3 for PIIANP (chromosome 8p23.2), 3.2 for COMP (chromosome 8q11.1), 2.0 for HA (chromosome 6q16.3), and 2.0 for C2C (chromosome 5q31.2). Herein, we report the first evidence of genetic susceptibility loci identified by OA-related biomarkers in an extended family. Our results demonstrate that serum concentrations of PIIANP, HA, COMP, and C2C have substantial heritable components, and using these biomarkers, several genetic loci potentially contributing to the genetic diversity of OA were identified.

  18. A genome-wide linkage and association study of musical aptitude identifies loci containing genes related to inner ear development and neurocognitive functions

    PubMed Central

    Oikkonen, J.; Huang, Y.; Onkamo, P.; Ukkola-Vuoti, L.; Raijas, P.; Karma, K.; Vieland, V. J.; Järvelä, I.

    2014-01-01

    Humans have developed the perception, production and processing of sounds into the art of music. A genetic contribution to these skills of musical aptitude has long been suggested. We performed a genome-wide scan in 76 pedigrees (767 individuals) characterized for the ability to discriminate pitch (SP), duration (ST) and sound patterns (KMT), which are primary capacities for music perception. Using the Bayesian linkage and association approach implemented in program package KELVIN, especially designed for complex pedigrees, several SNPs near genes affecting the functions of the auditory pathway and neurocognitive processes were identified. The strongest association was found at 3q21.3 (rs9854612) with combined SP, ST and KMT test scores (COMB). This region is located a few dozen kilobases upstream of the GATA binding protein 2 (GATA2) gene. GATA2 regulates the development of cochlear hair cells and the inferior colliculus (IC), which are important in tonotopic mapping. The highest probability of linkage was obtained for phenotype SP at 4p14, located next to the region harboring the protocadherin 7 gene, PCDH7. Two SNPs rs13146789 and rs13109270 of PCDH7 showed strong association. PCDH7 has been suggested to play a role in cochlear and amygdaloid complexes. Functional class analysis showed that inner ear and schizophrenia related genes were enriched inside the linked regions. This study is the first to show the importance of auditory pathway genes in musical aptitude. PMID:24614497

  19. A genome-wide linkage and association study of musical aptitude identifies loci containing genes related to inner ear development and neurocognitive functions.

    PubMed

    Oikkonen, J; Huang, Y; Onkamo, P; Ukkola-Vuoti, L; Raijas, P; Karma, K; Vieland, V J; Järvelä, I

    2015-02-01

    Humans have developed the perception, production and processing of sounds into the art of music. A genetic contribution to these skills of musical aptitude has long been suggested. We performed a genome-wide scan in 76 pedigrees (767 individuals) characterized for the ability to discriminate pitch (SP), duration (ST) and sound patterns (KMT), which are primary capacities for music perception. Using the Bayesian linkage and association approach implemented in program package KELVIN, especially designed for complex pedigrees, several single nucleotide polymorphisms (SNPs) near genes affecting the functions of the auditory pathway and neurocognitive processes were identified. The strongest association was found at 3q21.3 (rs9854612) with combined SP, ST and KMT test scores (COMB). This region is located a few dozen kilobases upstream of the GATA binding protein 2 (GATA2) gene. GATA2 regulates the development of cochlear hair cells and the inferior colliculus (IC), which are important in tonotopic mapping. The highest probability of linkage was obtained for phenotype SP at 4p14, located next to the region harboring the protocadherin 7 gene, PCDH7. Two SNPs rs13146789 and rs13109270 of PCDH7 showed strong association. PCDH7 has been suggested to play a role in cochlear and amygdaloid complexes. Functional class analysis showed that inner ear and schizophrenia-related genes were enriched inside the linked regions. This study is the first to show the importance of auditory pathway genes in musical aptitude.

  20. Genome-Wide Linkage Analysis of Quantitative Biomarker Traits of Osteoarthritis in a Large Multigenerational Extended Family

    PubMed Central

    Chen, Hsiang-Cheng; Kraus, Virginia Byers; Li, Yi-Ju; Nelson, Sarah; Haynes, Carol; Johnson, Jessica; Stabler, Thomas; Hauser, Elizabeth R.; Gregory, Simon G.; Kraus, William E.; Shah, Svati H.

    2013-01-01

    Objective The genetic contributions to the multifactorial disorder osteoarthritis (OA) have been increasingly recognized. Our goal was to use OA-related biomarkers of severity and disease burden as quantitative traits to identify genetic susceptibility loci for OA. Methods In a large multigenerational extended family (CARRIAGE family, n=350), we measured five OA-related biomarkers: HA (hyaluronan), COMP (cartilage oligomeric matrix protein), PIIANP (type IIA collagen N-propeptide), CPII (type II procollagen carboxy-propeptide), and C2C (type II collagen cleavage neoepitope). SNP markers (6,090) covering the whole genome were genotyped using the Illumina HumanLinkage-12 BeadChip. Variance components analysis as implemented in SOLAR was used to estimate heritabilities of the quantitative traits, and to calculate two-point and multi-point LOD scores using a polygenic model. Results Four of the five biomarkers showed significant heritability (p<0.01 age and sex adjusted h2r: PIIANP 0.57, HA 0.49, COMP 0.43, C2C 0.30). Fourteen of the 19 loci with multi-point LOD scores >1.5 were near or overlapped previously reported OA susceptibility loci. Four of these loci were identified by more than one biomarker. The maximum multi-point LOD scores for the heritable quantitative biomarker traits were LOD 4.3 for PIIANP (chromosome 8p23.2); LOD 3.2 for COMP (chromosome 8q11.1); LOD 2.0 for HA (chromosome 6q16.3); LOD 2.0 for C2C (chromosome 5q31.2). Conclusions We report the first evidence of genetic susceptibility loci identified by OA-related biomarkers in an extended family. Serum concentrations of PIIANP, HA, COMP and C2C have substantial heritable components and identified several genetic loci potentially contributing to the genetic diversity of OA. PMID:20187133

  1. FastTagger: an efficient algorithm for genome-wide tag SNP selection using multi-marker linkage disequilibrium

    PubMed Central

    2010-01-01

    Background Human genome contains millions of common single nucleotide polymorphisms (SNPs) and these SNPs play an important role in understanding the association between genetic variations and human diseases. Many SNPs show correlated genotypes, or linkage disequilibrium (LD), thus it is not necessary to genotype all SNPs for association study. Many algorithms have been developed to find a small subset of SNPs called tag SNPs that are sufficient to infer all the other SNPs. Algorithms based on the r2 LD statistic have gained popularity because r2 is directly related to statistical power to detect disease associations. Most of existing r2 based algorithms use pairwise LD. Recent studies show that multi-marker LD can help further reduce the number of tag SNPs. However, existing tag SNP selection algorithms based on multi-marker LD are both time-consuming and memory-consuming. They cannot work on chromosomes containing more than 100 k SNPs using length-3 tagging rules. Results We propose an efficient algorithm called FastTagger to calculate multi-marker tagging rules and select tag SNPs based on multi-marker LD. FastTagger uses several techniques to reduce running time and memory consumption. Our experiment results show that FastTagger is several times faster than existing multi-marker based tag SNP selection algorithms, and it consumes much less memory at the same time. As a result, FastTagger can work on chromosomes containing more than 100 k SNPs using length-3 tagging rules. FastTagger also produces smaller sets of tag SNPs than existing multi-marker based algorithms, and the reduction ratio ranges from 3%-9% when length-3 tagging rules are used. The generated tagging rules can also be used for genotype imputation. We studied the prediction accuracy of individual rules, and the average accuracy is above 96% when r2 ≥ 0.9. Conclusions Generating multi-marker tagging rules is a computation intensive task, and it is the bottleneck of existing multi-marker based tag

  2. A novel genome-wide microsatellite resource for species of Eucalyptus with linkage-to-physical correspondence on the reference genome sequence.

    PubMed

    Grattapaglia, Dario; Mamani, Eva M C; Silva-Junior, Orzenil B; Faria, Danielle A

    2015-03-01

    Keystone species in their native ranges, eucalypts, are ecologically and genetically very diverse, growing naturally along extensive latitudinal and altitudinal ranges and variable environments. Besides their ecological importance, eucalypts are also the most widely planted trees for sustainable forestry in the world. We report the development of a novel collection of 535 microsatellites for species of Eucalyptus, 494 designed from ESTs and 41 from genomic libraries. A selected subset of 223 was evaluated for individual identification, parentage testing, and ancestral information content in the two most extensively studied species, Eucalyptus grandis and Eucalyptus globulus. Microsatellites showed high transferability and overlapping allele size range, suggesting they have arisen still in their common ancestor and confirming the extensive genome conservation between these two species. A consensus linkage map with 437 microsatellites, the most comprehensive microsatellite-only genetic map for Eucalyptus, was built by assembling segregation data from three mapping populations and anchored to the Eucalyptus genome. An overall colinearity between recombination-based and physical positioning of 84% of the mapped microsatellites was observed, with some ordering discrepancies and sporadic locus duplications, consistent with the recently described whole genome duplication events in Eucalyptus. The linkage map covered 95.2% of the 605.8-Mbp assembled genome sequence, placing one microsatellite every 1.55 Mbp on average, and an overall estimate of physical to recombination distance of 618 kbp/cM. The genetic parameters estimates together with linkage and physical position data for this large set of microsatellites should assist marker choice for genome-wide population genetics and comparative mapping in Eucalyptus.

  3. Genome-wide search for genetic modulators in gene regulatory pathways: weighted window-based peak identification algorithm.

    PubMed

    Lee, Eunjee; Kim, Kyunga; Park, Taesung

    2011-06-01

    Genome-wide gene expression and genotype data have been integratively analyzed in expression quantitative trait loci (eQTL) studies to elucidate the genetics of gene transcription. Most eQTL analyses have focused on identifying polymorphic genetic variants that influence the expression levels of individual genes, and such analyses may have limitations in explaining gene regulatory pathways that are likely to involve multiple genes and their genetic and/or non-genetic modulators. We have developed a novel two-step method for identifying potential genetic modulators of transcription processes for multiple genes in a biological pathway. We proposed a new weighted window-based peak identification algorithm to improve the detection of genetic modulators for individual genes and employed a Poisson-based test to search for master genetic modulators of multiple genes. Here, we have illustrated this two-step approach by analyzing the gene expression data in the Centre d'Etude du Polymorphisme Humain (CEPH) lymphoblast cells and single nucleotide polymorphism chip data.

  4. EW_dmGWAS: edge-weighted dense module search for genome-wide association studies and gene expression profiles

    PubMed Central

    Wang, Quan; Yu, Hui; Zhao, Zhongming; Jia, Peilin

    2015-01-01

    Summary: We previously developed dmGWAS to search for dense modules in a human protein–protein interaction (PPI) network; it has since become a popular tool for network-assisted analysis of genome-wide association studies (GWAS). dmGWAS weights nodes by using GWAS signals. Here, we introduce an upgraded algorithm, EW_dmGWAS, to boost GWAS signals in a node- and edge-weighted PPI network. In EW_dmGWAS, we utilize condition-specific gene expression profiles for edge weights. Specifically, differential gene co-expression is used to infer the edge weights. We applied EW_dmGWAS to two diseases and compared it with other relevant methods. The results suggest that EW_dmGWAS is more powerful in detecting disease-associated signals. Availability and implementation: The algorithm of EW_dmGWAS is implemented in the R package dmGWAS_3.0 and is available at http://bioinfo.mc.vanderbilt.edu/dmGWAS. Contact: zhongming.zhao@vanderbilt.edu or peilin.jia@vanderbilt.edu Supplementary information: Supplementary materials are available at Bioinformatics online. PMID:25805723

  5. Genome-wide patterns of segregation and linkage disequilibrium: the construction of a linkage genetic map of the poplar rust fungus Melampsora larici-populina

    PubMed Central

    Pernaci, Michaël; De Mita, Stéphane; Andrieux, Axelle; Pétrowski, Jérémy; Halkett, Fabien; Duplessis, Sébastien; Frey, Pascal

    2014-01-01

    The poplar rust fungus Melampsora larici-populina causes significant yield reduction and severe economic losses in commercial poplar plantations. After several decades of breeding for qualitative resistance and subsequent breakdown of the released resistance genes, breeders now focus on quantitative resistance, perceived to be more durable. But quantitative resistance also can be challenged by an increase of aggressiveness in the pathogen. Thus, it is of primary importance to better understand the genetic architecture of aggressiveness traits. To this aim, our goal is to build a genetic linkage map for M. larici-populina in order to map quantitative trait loci related to aggressiveness. First, a large progeny of M. larici-populina was generated through selfing of the reference strain 98AG31 (which genome sequence is available) on larch plants, the alternate host of the poplar rust fungus. The progeny's meiotic origin was validated through a segregation analysis of 115 offspring with 14 polymorphic microsatellite markers, of which 12 segregated in the expected 1:2:1 Mendelian ratio. A microsatellite-based linkage disequilibrium analysis allowed us to identify one potential linkage group comprising two scaffolds. The whole genome of a subset of 47 offspring was resequenced using the Illumina HiSeq 2000 technology at a mean sequencing depth of 6X. The reads were mapped onto the reference genome of the parental strain and 144,566 SNPs were identified across the genome. Analysis of distribution and polymorphism of the SNPs along the genome led to the identification of 2580 recombination blocks. A second linkage disequilibrium analysis, using the recombination blocks as markers, allowed us to group 81 scaffolds into 23 potential linkage groups. These preliminary results showed that a high-density linkage map could be constructed by using high-quality SNPs based on low-coverage resequencing of a larger number of M. larici-populina offspring. PMID:25309554

  6. The impact of incomplete linkage disequilibrium and genetic model choice on the analysis and interpretation of genome-wide association studies.

    PubMed

    Iles, Mark M

    2010-07-01

    When conducting a genetic association study, it has previously been observed that a multiplicative risk model tends to fit better at a disease-associated marker locus than at the ungenotyped causative locus. This suggests that, while overall risk decreases as linkage disequilibrium breaks down, non-multiplicative components are more affected. This effect is investigated here, in particular the practical consequences it has on testing for trait/marker associations and the estimation of mode of inheritance and risk once an associated locus has been found. The extreme significance levels required for genome-wide association studies define a restricted range of detectable allele frequencies and effect sizes. For such parameters there is little to be gained by using a test that models the correct mode of inheritance rather than the multiplicative; thus the Cochran-Armitage trend test, which assumes a multiplicative model, is preferable to a more general model as it uses fewer degrees of freedom. Equally when estimating risk, it is likely that a multiplicative risk model will provide a good fit to the data, regardless of the underlying mode of inheritance at the true susceptibility locus. This may lead to problems in interpreting risk estimates.

  7. Genome-Wide Linkage and Association Mapping of Halo Blight Resistance in Common Bean to Race 6 of the Globally Important Bacterial Pathogen

    PubMed Central

    Tock, Andrew J.; Fourie, Deidré; Walley, Peter G.; Holub, Eric B.; Soler, Alvaro; Cichy, Karen A.; Pastor-Corrales, Marcial A.; Song, Qijian; Porch, Timothy G.; Hart, John P.; Vasconcellos, Renato C. C.; Vicente, Joana G.; Barker, Guy C.; Miklas, Phillip N.

    2017-01-01

    Pseudomonas syringae pv. phaseolicola (Psph) Race 6 is a globally prevalent and broadly virulent bacterial pathogen with devastating impact causing halo blight of common bean (Phaseolus vulgaris L.). Common bean lines PI 150414 and CAL 143 are known sources of resistance against this pathogen. We constructed high-resolution linkage maps for three recombinant inbred populations to map resistance to Psph Race 6 derived from the two common bean lines. This was complemented with a genome-wide association study (GWAS) of Race 6 resistance in an Andean Diversity Panel of common bean. Race 6 resistance from PI 150414 maps to a single major-effect quantitative trait locus (QTL; HB4.2) on chromosome Pv04 and confers broad-spectrum resistance to eight other races of the pathogen. Resistance segregating in a Rojo × CAL 143 population maps to five chromosome arms and includes HB4.2. GWAS detected one QTL (HB5.1) on chromosome Pv05 for resistance to Race 6 with significant influence on seed yield. The same HB5.1 QTL, found in both Canadian Wonder × PI 150414 and Rojo × CAL 143 populations, was effective against Race 6 but lacks broad resistance. This study provides evidence for marker-assisted breeding for more durable halo blight control in common bean by combining alleles of race-nonspecific resistance (HB4.2 from PI 150414) and race-specific resistance (HB5.1 from cv. Rojo). PMID:28736566

  8. Multipoint genome-wide linkage scan for nonword repetition in a multigenerational family further supports chromosome 13q as a locus for verbal trait disorders.

    PubMed

    Truong, D T; Shriberg, L D; Smith, S D; Chapman, K L; Scheer-Cohen, A R; DeMille, M M C; Adams, A K; Nato, A Q; Wijsman, E M; Eicher, J D; Gruen, J R

    2016-12-01

    Verbal trait disorders encompass a wide range of conditions and are marked by deficits in five domains that impair a person's ability to communicate: speech, language, reading, spelling, and writing. Nonword repetition is a robust endophenotype for verbal trait disorders that is sensitive to cognitive processes critical to verbal development, including auditory processing, phonological working memory, and motor planning and programming. In the present study, we present a six-generation extended pedigree with a history of verbal trait disorders. Using genome-wide multipoint variance component linkage analysis of nonword repetition, we identified a region spanning chromosome 13q14-q21 with LOD = 4.45 between 52 and 55 cM, spanning approximately 5.5 Mb on chromosome 13. This region overlaps with SLI3, a locus implicated in reading disability in families with a history of specific language impairment. Our study of a large multigenerational family with verbal trait disorders further implicates the SLI3 region in verbal trait disorders. Future studies will further refine the specific causal genetic factors in this locus on chromosome 13q that contribute to language traits.

  9. Genetic Diversity, Population Structure, and Linkage Disequilibrium of an Association-Mapping Panel Revealed by Genome-Wide SNP Markers in Sesame

    PubMed Central

    Cui, Chengqi; Mei, Hongxian; Liu, Yanyang; Zhang, Haiyang; Zheng, Yongzhan

    2017-01-01

    The characterization of genetic diversity and population structure can be used in tandem to detect reliable phenotype–genotype associations. In the present study, we genotyped a set of 366 sesame germplasm accessions by using 89,924 single-nucleotide polymorphisms (SNPs). The number of SNPs on each chromosome was consistent with the physical length of the respective chromosome, and the average marker density was approximately 2.67 kb/SNP. The genetic diversity analysis showed that the average nucleotide diversity of the panel was 1.1 × 10-3, with averages of 1.0 × 10-4, 2.7 × 10-4, and 3.6 × 10-4 obtained, respectively for three identified subgroups of the panel: Pop 1, Pop 2, and the Mixed. The genetic structure analysis revealed that these sesame germplasm accessions were structured primarily along the basis of their geographic collection, and that an extensive admixture occurred in the panel. The genome-wide linkage disequilibrium (LD) analysis showed that an average LD extended up to ∼99 kb. The genetic diversity and population structure revealed in this study should provide guidance to the future design of association studies and the systematic utilization of the genetic variation characterizing the sesame panel. PMID:28729877

  10. Genetic Diversity, Population Structure, and Linkage Disequilibrium of an Association-Mapping Panel Revealed by Genome-Wide SNP Markers in Sesame.

    PubMed

    Cui, Chengqi; Mei, Hongxian; Liu, Yanyang; Zhang, Haiyang; Zheng, Yongzhan

    2017-01-01

    The characterization of genetic diversity and population structure can be used in tandem to detect reliable phenotype-genotype associations. In the present study, we genotyped a set of 366 sesame germplasm accessions by using 89,924 single-nucleotide polymorphisms (SNPs). The number of SNPs on each chromosome was consistent with the physical length of the respective chromosome, and the average marker density was approximately 2.67 kb/SNP. The genetic diversity analysis showed that the average nucleotide diversity of the panel was 1.1 × 10(-3), with averages of 1.0 × 10(-4), 2.7 × 10(-4), and 3.6 × 10(-4) obtained, respectively for three identified subgroups of the panel: Pop 1, Pop 2, and the Mixed. The genetic structure analysis revealed that these sesame germplasm accessions were structured primarily along the basis of their geographic collection, and that an extensive admixture occurred in the panel. The genome-wide linkage disequilibrium (LD) analysis showed that an average LD extended up to ∼99 kb. The genetic diversity and population structure revealed in this study should provide guidance to the future design of association studies and the systematic utilization of the genetic variation characterizing the sesame panel.

  11. Genome-wide linkage analysis of QTL for growth and body composition employing the PorcineSNP60 BeadChip

    PubMed Central

    2012-01-01

    Background The traditional strategy to map QTL is to use linkage analysis employing a limited number of markers. These analyses report wide QTL confidence intervals, making very difficult to identify the gene and polymorphisms underlying the QTL effects. The arrival of genome-wide panels of SNPs makes available thousands of markers increasing the information content and therefore the likelihood of detecting and fine mapping QTL regions. The aims of the current study are to confirm previous QTL regions for growth and body composition traits in different generations of an Iberian x Landrace intercross (IBMAP) and especially identify new ones with narrow confidence intervals by employing the PorcineSNP60 BeadChip in linkage analyses. Results Three generations (F3, Backcross 1 and Backcross 2) of the IBMAP and their related animals were genotyped with PorcineSNP60 BeadChip. A total of 8,417 SNPs equidistantly distributed across autosomes were selected after filtering by quality, position and frequency to perform the QTL scan. The joint and separate analyses of the different IBMAP generations allowed confirming QTL regions previously identified in chromosomes 4 and 6 as well as new ones mainly for backfat thickness in chromosomes 4, 5, 11, 14 and 17 and shoulder weight in chromosomes 1, 2, 9 and 13; and many other to the chromosome-wide signification level. In addition, most of the detected QTLs displayed narrow confidence intervals, making easier the selection of positional candidate genes. Conclusions The use of higher density of markers has allowed to confirm results obtained in previous QTL scans carried out with microsatellites. Moreover several new QTL regions have been now identified in regions probably not covered by markers in previous scans, most of these QTLs displayed narrow confidence intervals. Finally, prominent putative biological and positional candidate genes underlying those QTL effects are listed based on recent porcine genome annotation. PMID

  12. Genome-wide linkage and positional candidate gene study of blood pressure response to dietary potassium intervention: the genetic epidemiology network of salt sensitivity study.

    PubMed

    Kelly, Tanika N; Hixson, James E; Rao, Dabeeru C; Mei, Hao; Rice, Treva K; Jaquish, Cashell E; Shimmin, Lawrence C; Schwander, Karen; Chen, Chung-Shuian; Liu, Depei; Chen, Jichun; Bormans, Concetta; Shukla, Pramila; Farhana, Naveed; Stuart, Colin; Whelton, Paul K; He, Jiang; Gu, Dongfeng

    2010-12-01

    Genetic determinants of blood pressure (BP) response to potassium, or potassium sensitivity, are largely unknown. We conducted a genome-wide linkage scan and positional candidate gene analysis to identify genetic determinants of potassium sensitivity. A total of 1906 Han Chinese participants took part in a 7-day high-sodium diet followed by a 7-day high-sodium plus potassium dietary intervention. BP measurements were obtained at baseline and after each intervention using a random-zero sphygmomanometer. Significant linkage signals (logarithm of odds [LOD] score, >3) for BP responses to potassium were detected at chromosomal regions 3q24-q26.1, 3q28, and 11q22.3-q24.3. Maximum multipoint LOD scores of 3.09 at 3q25.2 and 3.41 at 11q23.3 were observed for absolute diastolic BP (DBP) and mean arterial pressure (MAP) responses, respectively. Linkage peaks of 3.56 at 3q25.1 and 3.01 at 11q23.3 for percent DBP response and 3.22 at 3q25.2, 3.01 at 3q28, and 4.48 at 11q23.3 for percent MAP response also were identified. Angiotensin II receptor, type 1 (AGTR1), single-nucleotide polymorphism rs16860760 in the 3q24-q26.1 region was significantly associated with absolute and percent systolic BP responses to potassium (P=0.0008 and P=0.0006, respectively). Absolute (95% CI) systolic BP responses for genotypes C/C, C/T, and T/T were -3.71 (-4.02 to -3.40), -2.62 (-3.38 to -1.85), and 1.03 (-3.73 to 5.79) mm Hg, respectively, and percent responses (95% CI) were -3.07 (-3.33 to -2.80), -2.07 (-2.74 to -1.41), and 0.90 (-3.20 to 4.99), respectively. Similar trends were observed for DBP and MAP responses. Genetic regions on chromosomes 3 and 11 may harbor important susceptibility loci for potassium sensitivity. Furthermore, the AGTR1 gene was a significant predictor of BP responses to potassium intake.

  13. Genome-wide Linkage and Positional Candidate Gene Study of Blood Pressure Response to Dietary Potassium Intervention: The GenSalt Study

    PubMed Central

    Kelly, Tanika N.; Hixson, James E.; Rao, Dabeeru C.; Mei, Hao; Rice, Treva K.; Jaquish, Cashell E.; Shimmin, Lawrence C.; Schwander, Karen; Chen, Chung-Shuian; Liu, Depei; Chen, Jichun; Bormans, Concetta; Shukla, Pramila; Farhana, Naveed; Stuart, Colin; Whelton, Paul K.; He, Jiang; Gu, Dongfeng

    2011-01-01

    Background Genetic determinants of BP response to potassium, or potassium sensitivity, are largely unknown. We conducted a genome-wide linkage scan and positional candidate gene analysis to identify genetic determinants of potassium sensitivity. Methods and Results 1,906 Han Chinese participants took part in a 7-day high-sodium followed by a 7-day high-sodium plus potassium dietary intervention. BP measurements were obtained at baseline and following each intervention using a random-zero sphygmomanometer. Significant linkage signals (LOD>3) for BP responses to potassium were detected at chromosomal regions 3q24-q26.1, 3q28, and 11q22.3-q24.3. Maximum multipoint LOD scores of 3.09 at 3q25.2 and 3.41 at 11q23.3 were observed for absolute DBP and MAP responses, respectively. Linkage peaks of 3.56 at 3q25.1 and 3.01 at 11q23.3 for percent DBP response and 3.22 at 3q25.2, 3.01 at 3q28, and 4.48 at 11q23.3 for percent MAP response were also identified. AGTR1 SNP rs16860760 in the 3q24-q26.1 region was significantly associated with absolute and percent systolic (SBP) responses to potassium (p-values=0.0008 and 0.0006, respectively). Absolute SBP responses (95% CI) for genotypes C/C, C/T, and T/T were: −3.71 (−4.02, −3.40), −2.62 (−3.38, −1.85), and 1.03 (−3.73, 5.79) mmHg, respectively; and percent responses (95% CI) were: −3.07 (−3.33, −2.80), −2.07 (−2.74, −1.41), and 0.90 (−3.20, 4.99), respectively. Similar trends were observed for DBP and MAP responses. Conclusions Genetic regions on chromosomes 3 and 11 may harbor important susceptibility loci for potassium sensitivity. Furthermore, the AGTR1 gene was a significant predictor of BP responses to potassium intake. Clinical Trial Registration Information http://clinicaltrials.gov; Identifier: NCT00721721 PMID:20861505

  14. Genetic correlates of brain aging on MRI and cognitive test measures: a genome-wide association and linkage analysis in the Framingham study

    PubMed Central

    Seshadri, Sudha; DeStefano, Anita L; Au, Rhoda; Massaro, Joseph M; Beiser, Alexa S; Kelly-Hayes, Margaret; Kase, Carlos S; D'Agostino, Ralph B; DeCarli, Charles; Atwood, Larry D; Wolf, Philip A

    2007-01-01

    Background Brain magnetic resonance imaging (MRI) and cognitive tests can identify heritable endophenotypes associated with an increased risk of developing stroke, dementia and Alzheimer's disease (AD). We conducted a genome-wide association (GWA) and linkage analysis exploring the genetic basis of these endophenotypes in a community-based sample. Methods A total of 705 stroke- and dementia-free Framingham participants (age 62 +9 yrs, 50% male) who underwent volumetric brain MRI and cognitive testing (1999–2002) were genotyped. We used linear models adjusting for first degree relationships via generalized estimating equations (GEE) and family based association tests (FBAT) in additive models to relate qualifying single nucleotide polymorphisms (SNPs, 70,987 autosomal on Affymetrix 100K Human Gene Chip with minor allele frequency ≥ 0.10, genotypic call rate ≥ 0.80, and Hardy-Weinberg equilibrium p-value ≥ 0.001) to multivariable-adjusted residuals of 9 MRI measures including total cerebral brain (TCBV), lobar, ventricular and white matter hyperintensity (WMH) volumes, and 6 cognitive factors/tests assessing verbal and visuospatial memory, visual scanning and motor speed, reading, abstract reasoning and naming. We determined multipoint identity-by-descent utilizing 10,592 informative SNPs and 613 short tandem repeats and used variance component analyses to compute LOD scores. Results The strongest gene-phenotype association in FBAT analyses was between SORL1 (rs1131497; p = 3.2 × 10-6) and abstract reasoning, and in GEE analyses between CDH4 (rs1970546; p = 3.7 × 10-8) and TCBV. SORL1 plays a role in amyloid precursor protein processing and has been associated with the risk of AD. Among the 50 strongest associations (25 each by GEE and FBAT) were other biologically interesting genes. Polymorphisms within 28 of 163 candidate genes for stroke, AD and memory impairment were associated with the endophenotypes studied at p < 0.001. We confirmed our previously

  15. Genome-wide scan for hypertension linkage to chromosome 12q23.1 - q23.3 in a Chinese family.

    PubMed

    Dong, Yan; Yang, Lin; Fang, Fang; Zhang, Jing; Jiang, Gengru; Xu, Shijie

    2013-05-01

    Essential hypertension is a multifactorial disorder with a complex phenotype. Here we report a susceptibility locus for the hypertension mapped by a genome-wide microsatellite scanning in an affected Chinese family, in which 11 members had hypertension before the age of 40. A total of 22 individuals from a single family from Shanghai, PR China, were genotyped on more than 400 microsatellite markers with a spacing gap of less than 10 cm for nearly the entire scanned genome. Linkage analysis suggested that an affected disorder is linked to a locus in the chromosome interval 12q23.1 to 12q23.3; two-point parametric analysis showed a logarithm of odds (LOD) score of 2.97 for the marker D12S346 (12q23.1) and 1.40 for the marker D12S78 (12q23.3). Fine mapping and haplotype analysis subsequently confirmed that eight continuous markers (D12Sac023161, D12S1706, D12S346, D12S1588, D12S1607, D12Sac010202, D12S78, D12Sac084356) had positive LOD with a maximum two-point LOD score of 3.34 for the marker D12S1706 and a maximum multi-point LOD score was 2.4002 for D12Sac010202, their NPL scores were 10.9091 for D12S1706 and 10.9114 for D12Sac010202. A novel locus for essential hypertension was identified on chromosome 12q23.1 - q23.3. This finding implies that the region 12q23.1 to 12q23.3 might encompass a susceptible gene that caused hypertension in this Chinese family.

  16. Identification of Major Quantitative Trait Loci for Seed Oil Content in Soybeans by Combining Linkage and Genome-Wide Association Mapping.

    PubMed

    Cao, Yongce; Li, Shuguang; Wang, Zili; Chang, Fangguo; Kong, Jiejie; Gai, Junyi; Zhao, Tuanjie

    2017-01-01

    Soybean oil is the most widely produced vegetable oil in the world and its content in soybean seed is an important quality trait in breeding programs. More than 100 quantitative trait loci (QTLs) for soybean oil content have been identified. However, most of them are genotype specific and/or environment sensitive. Here, we used both a linkage and association mapping methodology to dissect the genetic basis of seed oil content of Chinese soybean cultivars in various environments in the Jiang-Huai River Valley. One recombinant inbred line (RIL) population (NJMN-RIL), with 104 lines developed from a cross between M8108 and NN1138-2, was planted in five environments to investigate phenotypic data, and a new genetic map with 2,062 specific-locus amplified fragment markers was constructed to map oil content QTLs. A derived F2 population between MN-5 (a line of NJMN-RIL) and NN1138-2 was also developed to confirm one major QTL. A soybean breeding germplasm population (279 lines) was established to perform a genome-wide association study (GWAS) using 59,845 high-quality single nucleotide polymorphism markers. In the NJMN-RIL population, 8 QTLs were found that explained a range of phenotypic variance from 6.3 to 26.3% in certain planting environments. Among them, qOil-5-1, qOil-10-1, and qOil-14-1 were detected in different environments, and qOil-5-1 was further confirmed using the secondary F2 population. Three loci located on chromosomes 5 and 20 were detected in a 2-year long GWAS, and one locus that overlapped with qOil-5-1 was found repeatedly and treated as the same locus. qOil-5-1 was further localized to a linkage disequilibrium block region of approximately 440 kb. These results will not only increase our understanding of the genetic control of seed oil content in soybean, but will also be helpful in marker-assisted selection for breeding high seed oil content soybean and gene cloning to elucidate the mechanisms of seed oil content.

  17. Genome-wide linkage scans for type 2 diabetes mellitus in four ethnically diverse populations-significant evidence for linkage on chromosome 4q in African Americans: the Family Investigation of Nephropathy and Diabetes Research Group.

    PubMed

    Malhotra, Alka; Igo, Robert P; Thameem, Farook; Kao, W H Linda; Abboud, Hanna E; Adler, Sharon G; Arar, Nedal H; Bowden, Donald W; Duggirala, Ravindranath; Freedman, Barry I; Goddard, Katrina A B; Ipp, Eli; Iyengar, Sudha K; Kimmel, Paul L; Knowler, William C; Kohn, Orly; Leehey, David; Meoni, Lucy A; Nelson, Robert G; Nicholas, Susanne B; Parekh, Rulan S; Rich, Stephen S; Chen, Yii-Der I; Saad, Mohammed F; Scavini, Marina; Schelling, Jeffrey R; Sedor, John R; Shah, Vallabh O; Taylor, Kent D; Thornley-Brown, Denyse; Zager, Philip G; Horvath, Amanda; Hanson, Robert L

    2009-11-01

    Previous studies have shown that in addition to environmental influences, type 2 diabetes mellitus (T2DM) has a strong genetic component. The goal of the current study is to identify regions of linkage for T2DM in ethnically diverse populations. Phenotypic and genotypic data were obtained from African American (AA; total number of individuals [N] = 1004), American Indian (AI; N = 883), European American (EA; N = 537), and Mexican American (MA; N = 1634) individuals from the Family Investigation of Nephropathy and Diabetes. Non-parametric linkage analysis, using an average of 4404 SNPs, was performed in relative pairs affected with T2DM in each ethnic group. In addition, family-based tests were performed to detect association with T2DM. Statistically significant evidence for linkage was observed on chromosome 4q21.1 (LOD = 3.13; genome-wide p = 0.04) in AA. In addition, a total of 11 regions showed suggestive evidence for linkage (estimated at LOD > 1.71), with the highest LOD scores on chromosomes 12q21.31 (LOD = 2.02) and 22q12.3 (LOD = 2.38) in AA, 2p11.1 (LOD = 2.23) in AI, 6p12.3 (LOD = 2.77) in EA, and 13q21.1 (LOD = . 2.24) in MA. While no region overlapped across all ethnic groups, at least five loci showing LOD > 1.71 have been identified in previously published studies. The results from this study provide evidence for the presence of genes affecting T2DM on chromosomes 4q, 12q, and 22q in AA; 6p in EA; 2p in AI; and 13q in MA. The strong evidence for linkage on chromosome 4q in AA provides important information given the paucity of diabetes genetic studies in this population.

  18. Genome-wide linkage scans for type 2 diabetes mellitus in four ethnically diverse populations; significant evidence for linkage on chromosome 4q in African Americans: the Family Investigation of Nephropathy and Diabetes (FIND) Research Group

    PubMed Central

    Malhotra, Alka; Igo, Robert P.; Thameem, Farook; Kao, W.H. Linda; Abboud, Hanna E.; Adler, Sharon G.; Arar, Nedal H.; Bowden, Donald W.; Duggirala, Ravindranath; Freedman, Barry I.; Goddard, Katrina A.B.; Ipp, Eli; Iyengar, Sudha K.; Kimmel, Paul L.; Knowler, William C.; Kohn, Orly; Leehey, David; Meoni, Lucy A.; Nelson, Robert G.; Nicholas, Susanne B.; Parekh, Rulan S.; Rich, Stephen S.; Chen, Yii-Der I.; Saad, Mohammed F.; Scavini, Marina; Schelling, Jeffrey R.; Sedor, John R.; Shah, Vallabh O.; Taylor, Kent D.; Thornley-Brown, Denyse; Zager, Philip G.; Horvath, Amanda; Hanson, Robert L.

    2009-01-01

    Background Previous studies have shown that, in addition to environmental influences, type 2 diabetes mellitus (T2DM) has a strong genetic component. The goal of the current study is to identify regions of linkage for T2DM in ethnically diverse populations. Methods Phenotypic and genotypic data were obtained from African American (AA; total number of individuals (N)=1004), American Indian (AI; N=883), European American (EA; N=537), and Mexican American (MA; N=1634) individuals from the Family Investigation of Nephropathy and Diabetes. Nonparametric linkage analysis, using an average of 4,404 SNPs, was performed in relative pairs affected with T2DM in each ethnic group. In addition, family-based tests were performed to detect association with T2DM. Results Statistically significant evidence for linkage was observed on chromosomes 4q21.1 (LOD=3.13; genome-wide p=0.04) in AA. In addition, a total of eleven regions showed suggestive evidence for linkage (estimated at LOD>1.71), with the highest LOD scores on chromosomes 12q21.31 (LOD=2.02) and 22q12.3 (LOD=2.38) in AA, 2p11.1 (LOD=2.23) in AI, 6p12.3 (LOD=2.77) in EA, and 13q21.1 (LOD=2.24) in MA. While no region overlapped across all ethnic groups, at least five loci showing LOD>1.71 have been identified in previously published studies. Conclusions The results from this study provide evidence for the presence of genes affecting T2DM on chromosomes 4q, 12q, and 22q in AA, 6p in EA, 2p in AI, and 13q in MA. The strong evidence for linkage on chromosome 4q in AA provides important information given the paucity of diabetes genetic studies in this population. PMID:19795399

  19. Genome-wide linkage analysis of 1233 prostate cancer pedigrees from the International Consortium for Prostate Cancer Genetics using novel sumLINK and sumLOD analyses

    PubMed Central

    Christensen, G. Bryce; Baffoe-Bonnie, Agnes B.; George, Asha; Powell, Isaac; Bailey-Wilson, Joan E.; Carpten, John D.; Giles, Graham G.; Hopper, John L.; Severi, Gianluca; English, Dallas R.; Foulkes, William D.; Maehle, Lovise; Moller, Pal; Eeles, Ros; Easton, Douglas; Badzioch, Michael D.; Whittemore, Alice S.; Oakley-Girvan, Ingrid; Hsieh, Chih-Lin; Dimitrov, Latchezar; Xu, Jianfeng; Stanford, Janet L.; Johanneson, Bo; Deutsch, Kerry; McIntosh, Laura; Ostrander, Elaine A.; Wiley, Kathleen E.; Isaacs, Sarah D.; Walsh, Patrick C.; Isaacs, William B.; Thibodeau, Stephen N.; McDonnell, Shannon K.; Hebbring, Scott; Schaid, Daniel J.; Lange, Ethan M.; Cooney, Kathleen A.; Tammela, Teuvo L.J.; Schleutker, Johanna; Paiss, Thomas; Maier, Christiane; Grönberg, Henrik; Wiklund, Fredrik; Emanuelsson, Monica; Farnham, James M.; Cannon-Albright, Lisa A.; Camp, Nicola J.

    2012-01-01

    Background Prostate cancer is generally believed to have a strong inherited component, but the search for susceptibility genes has been hindered by the effects of genetic heterogeneity. The recently developed sumLINK and sumLOD statistics are powerful tools for linkage analysis in the presence of heterogeneity. Methods We performed a secondary analysis of 1233 prostate cancer pedigrees from the International Consortium for Prostate Cancer Genetics (ICPCG) using two novel statistics, the sumLINK and sumLOD. For both statistics, dominant and recessive genetic models were considered. False discovery rate (FDR) analysis was conducted to assess the effects of multiple testing. Results Our analysis identified significant linkage evidence at chromosome 22q12, confirming previous findings by the initial conventional analyses of the same ICPCG data. Twelve other regions were identified with genomewide suggestive evidence for linkage. Seven regions (1q23, 5q11, 5q35, 6p21, 8q12, 11q13, 20p11-q11) are near loci previously identified in the initial ICPCG pooled data analysis or the subset of aggressive prostate cancer (PC) pedigrees. Three other regions (1p12, 8p23, 19q13) confirm loci reported by others, and two (2p24, 6q27) are novel susceptibility loci. FDR testing indicates that over 70% of these results are likely true positive findings. Statistical recombinant mapping narrowed regions to an average of 9 cM. Conclusions Our results represent genomic regions with the greatest consistency of positive linkage evidence across a very large collection of high-risk prostate cancer pedigrees using new statistical tests that deal powerfully with heterogeneity. These regions are excellent candidates for further study to identify prostate cancer predisposition genes. PMID:20333727

  20. Development and Integration of Genome-Wide Polymorphic Microsatellite Markers onto a Reference Linkage Map for Constructing a High-Density Genetic Map of Chickpea.

    PubMed

    Khajuria, Yash Paul; Saxena, Maneesha S; Gaur, Rashmi; Chattopadhyay, Debasis; Jain, Mukesh; Parida, Swarup K; Bhatia, Sabhyata

    2015-01-01

    The identification of informative in silico polymorphic genomic and genic microsatellite markers by comparing the genome and transcriptome sequences of crop genotypes is a rapid, cost-effective and non-laborious approach for large-scale marker validation and genotyping applications, including construction of high-density genetic maps. We designed 1494 markers, including 1016 genomic and 478 transcript-derived microsatellite markers showing in-silico fragment length polymorphism between two parental genotypes (Cicer arietinum ICC4958 and C. reticulatum PI489777) of an inter-specific reference mapping population. High amplification efficiency (87%), experimental validation success rate (81%) and polymorphic potential (55%) of these microsatellite markers suggest their effective use in various applications of chickpea genetics and breeding. Intra-specific polymorphic potential (48%) detected by microsatellite markers in 22 desi and kabuli chickpea genotypes was lower than inter-specific polymorphic potential (59%). An advanced, high-density, integrated and inter-specific chickpea genetic map (ICC4958 x PI489777) having 1697 map positions spanning 1061.16 cM with an average inter-marker distance of 0.625 cM was constructed by assigning 634 novel informative transcript-derived and genomic microsatellite markers on eight linkage groups (LGs) of our prior documented, 1063 marker-based genetic map. The constructed genome map identified 88, including four major (7-23 cM) longest high-resolution genomic regions on LGs 3, 5 and 8, where the maximum number of novel genomic and genic microsatellite markers were specifically clustered within 1 cM genetic distance. It was for the first time in chickpea that in silico FLP analysis at genome-wide level was carried out and such a large number of microsatellite markers were identified, experimentally validated and further used in genetic mapping. To best of our knowledge, in the presently constructed genetic map, we mapped highest

  1. Development and Integration of Genome-Wide Polymorphic Microsatellite Markers onto a Reference Linkage Map for Constructing a High-Density Genetic Map of Chickpea

    PubMed Central

    Gaur, Rashmi; Chattopadhyay, Debasis; Jain, Mukesh; Parida, Swarup K.; Bhatia, Sabhyata

    2015-01-01

    The identification of informative in silico polymorphic genomic and genic microsatellite markers by comparing the genome and transcriptome sequences of crop genotypes is a rapid, cost-effective and non-laborious approach for large-scale marker validation and genotyping applications, including construction of high-density genetic maps. We designed 1494 markers, including 1016 genomic and 478 transcript-derived microsatellite markers showing in-silico fragment length polymorphism between two parental genotypes (Cicer arietinum ICC4958 and C. reticulatum PI489777) of an inter-specific reference mapping population. High amplification efficiency (87%), experimental validation success rate (81%) and polymorphic potential (55%) of these microsatellite markers suggest their effective use in various applications of chickpea genetics and breeding. Intra-specific polymorphic potential (48%) detected by microsatellite markers in 22 desi and kabuli chickpea genotypes was lower than inter-specific polymorphic potential (59%). An advanced, high-density, integrated and inter-specific chickpea genetic map (ICC4958 x PI489777) having 1697 map positions spanning 1061.16 cM with an average inter-marker distance of 0.625 cM was constructed by assigning 634 novel informative transcript-derived and genomic microsatellite markers on eight linkage groups (LGs) of our prior documented, 1063 marker-based genetic map. The constructed genome map identified 88, including four major (7–23 cM) longest high-resolution genomic regions on LGs 3, 5 and 8, where the maximum number of novel genomic and genic microsatellite markers were specifically clustered within 1 cM genetic distance. It was for the first time in chickpea that in silico FLP analysis at genome-wide level was carried out and such a large number of microsatellite markers were identified, experimentally validated and further used in genetic mapping. To best of our knowledge, in the presently constructed genetic map, we mapped highest

  2. Genome-wide significant linkage to IgG subclass responses against Plasmodium falciparum antigens on chromosomes 8p22-p21, 9q34 and 20q13.

    PubMed

    Brisebarre, A; Kumulungui, B; Sawadogo, S; Afridi, S; Fumoux, F; Rihet, P

    2015-01-01

    A genome-wide scan was conducted for the levels of total immunoglobulin G (IgG) and IgG subclasses directed against Plasmodium falciparum antigens in an urban population living in Burkina Faso. Non-parametric multipoint linkage analysis provided three chromosomal regions with genome-wide significant evidence (logarithm of the odds (LOD) score >3.6), and five chromosomal regions with genome-wide suggestive evidence (LOD score >2.2). IgG3 levels were significantly linked to chromosomes 8p22-p21 and 20q13, whereas IgG4 levels were significantly linked to chromosome 9q34. In addition, we detected suggestive linkage of IgG1 levels to chromosomes 18p11-q12 and 18q12-q21, IgG4 levels to chromosomes 1p31 and 12q24 and IgG levels to chromosome 6p24-p21. Moreover, we genotyped genetic markers located within the regions of interest in a rural population living in Burkina Faso. We detected genome-wide significant and suggestive linkage results when combining the two study populations for chromosomes 1p31, 6p24-p21, 8p22-p21, 9q34, 12q24 and 20q13. Because high anti-parasite IgG3 and low anti-parasite IgG4 levels were associated with malaria resistance, the chromosomal regions linked to IgG3 and IgG4 levels are of special interest. Although the results should be confirmed in an independent population, they may provide new insights in understanding both the genetic control of IgG production and malaria resistance.

  3. High-resolution genetic map for understanding the effect of genome-wide recombination rate, selection sweep and linkage disequilibrium on nucleotide diversity in watermelon

    USDA-ARS?s Scientific Manuscript database

    Genotyping by sequencing (GBS) technology was used to identify a set of 9,933 single nucleotide polymorphism (SNP) markers for constructing a high-resolution genetic map of 1,087 cM for watermelon. The genome-wide variation of recombination rate (GWRR) across the map was evaluated and a positive co...

  4. A genome-wide search for common SNP x SNP interactions on the risk of venous thrombosis

    PubMed Central

    2013-01-01

    Background Venous Thrombosis (VT) is a common multifactorial disease with an estimated heritability between 35% and 60%. Known genetic polymorphisms identified so far only explain ~5% of the genetic variance of the disease. This study was aimed to investigate whether pair-wise interactions between common single nucleotide polymorphisms (SNPs) could exist and modulate the risk of VT. Methods A genome-wide SNP x SNP interaction analysis on VT risk was conducted in a French case–control study and the most significant findings were tested for replication in a second independent French case–control sample. The results obtained in the two studies totaling 1,953 cases and 2,338 healthy subjects were combined into a meta-analysis. Results The smallest observed p-value for interaction was p = 6.00 10-11 but it did not pass the Bonferroni significance threshold of 1.69 10-12 correcting for the number of investigated interactions that was 2.96 1010. Among the 37 suggestive pair-wise interactions with p-value less than 10-8, one was further shown to involve two SNPs, rs9804128 (IGFS21 locus) and rs4784379 (IRX3 locus) that demonstrated significant interactive effects (p = 4.83 10-5) on the variability of plasma Factor VIII levels, a quantitative biomarker of VT risk, in a sample of 1,091 VT patients. Conclusion This study, the first genome-wide SNP interaction analysis conducted so far on VT risk, suggests that common SNPs are unlikely exerting strong interactive effects on the risk of disease. PMID:23509962

  5. Identification of New Resistance Loci to African Stem Rust Race TTKSK in Tetraploid Wheats Based on Linkage and Genome-Wide Association Mapping

    PubMed Central

    Laidò, Giovanni; Panio, Giosuè; Marone, Daniela; Russo, Maria A.; Ficco, Donatella B. M.; Giovanniello, Valentina; Cattivelli, Luigi; Steffenson, Brian; de Vita, Pasquale; Mastrangelo, Anna M.

    2015-01-01

    Stem rust, caused by Puccinia graminis Pers. f. sp. tritici Eriks. and E. Henn. (Pgt), is one of the most destructive diseases of wheat. Races of the pathogen in the “Ug99 lineage” are of international concern due to their virulence for widely used stem rust resistance genes and their spread throughout Africa. Disease resistant cultivars provide one of the best means for controlling stem rust. To identify quantitative trait loci (QTL) conferring resistance to African stem rust race TTKSK at the seedling stage, we evaluated an association mapping (AM) panel consisting of 230 tetraploid wheat accessions under greenhouse conditions. A high level of phenotypic variation was observed in response to race TTKSK in the AM panel, allowing for genome-wide association mapping of resistance QTL in wild, landrace, and cultivated tetraploid wheats. Thirty-five resistance QTL were identified on all chromosomes, and seventeen are of particular interest as identified by multiple associations. Many of the identified resistance loci were coincident with previously identified rust resistance genes; however, nine on chromosomes 1AL, 2AL, 4AL, 5BL, and 7BS may be novel. To validate AM results, a biparental population of 146 recombinant inbred lines was also considered, which derived from a cross between the resistant cultivar “Cirillo” and susceptible “Neodur.” The stem rust resistance of Cirillo was conferred by a single gene on the distal region of chromosome arm 6AL in an interval map coincident with the resistance gene Sr13, and confirmed one of the resistance loci identified by AM. A search for candidate resistance genes was carried out in the regions where QTL were identified, and many of them corresponded to NBS-LRR genes and protein kinases with LRR domains. The results obtained in the present study are of great interest as a high level of genetic variability for resistance to race TTKSK was described in a germplasm panel comprising most of the tetraploid wheat sub

  6. A genome-wide search for type 2 diabetes susceptibility genes in West Africans: the Africa America Diabetes Mellitus (AADM) Study.

    PubMed

    Rotimi, Charles N; Chen, Guanjie; Adeyemo, Adebowale A; Furbert-Harris, Paulette; Parish-Gause, Debra; Zhou, Jie; Berg, Kate; Adegoke, Olufemi; Amoah, Albert; Owusu, Samuel; Acheampong, Joseph; Agyenim-Boateng, Kofi; Eghan, Benjamin A; Oli, Johnnie; Okafor, Godfrey; Ofoegbu, Ester; Osotimehin, Babatunde; Abbiyesuku, Fayeofori; Johnson, Thomas; Rufus, Theresa; Fasanmade, Olufemi; Kittles, Rick; Daniel, Harold; Chen, Yuanxiu; Dunston, Georgia; Collins, Francis S; Guass, Debra

    2004-03-01

    The incidence of type 2 diabetes is growing rapidly, not only in developed countries but also worldwide. We chose to study type 2 diabetes in West Africa, where diabetes is less common than in the U.S., reasoning that in an environment where calories are less abundant, incident cases of type 2 diabetes might carry a proportionately greater genetic component. Through the Africa America Diabetes Mellitus (AADM) study, we carried out a genome-wide linkage analysis of type 2 diabetes in a cohort of 343 affected sibling pairs (691 individuals) enrolled from five West African centers in two countries (Ghana: Accra and Kumasi; Nigeria: Enugu, Ibadan, and Lagos). A total of 390 polymorphic markers were genotyped, and multipoint linkage analysis was conducted using the GENEHUNTER-PLUS and ASM programs. Suggestive evidence of linkage was observed in four regions on three chromosomes (12, 19, and 20). The two largest logarithm of odds scores of 2.63 and 1.92 for chromosomes 20q13.3 and 12q24, respectively, are particularly interesting because these regions have been reported to harbor diabetes susceptibility genes in several other populations and ethnic groups. Given the history of forced migration of West African populations during the slave trade, these results should have considerable relevance to the study of type 2 diabetes in African Americans.

  7. Genome-wide search for Zelda-like chromatin signatures identifies GAF as a pioneer factor in early fly development.

    PubMed

    Moshe, Arbel; Kaplan, Tommy

    2017-07-04

    The protein Zelda was shown to play a key role in early Drosophila development, binding thousands of promoters and enhancers prior to maternal-to-zygotic transition (MZT), and marking them for transcriptional activation. Recently, we showed that Zelda acts through specific chromatin patterns of histone modifications to mark developmental enhancers and active promoters. Intriguingly, some Zelda sites still maintain these chromatin patterns in Drosophila embryos lacking maternal Zelda protein. This suggests that additional Zelda-like pioneer factors may act in early fly embryos. We developed a computational method to analyze and refine the chromatin landscape surrounding early Zelda peaks, using a multichannel spectral clustering. This allowed us to characterize their chromatin patterns through MZT (mitotic cycles 8-14). Specifically, we focused on H3K4me1, H3K4me3, H3K18ac, H3K27ac, and H3K27me3 and identified three different classes of chromatin signatures, matching "promoters," "enhancers" and "transiently bound" Zelda peaks. We then further scanned the genome using these chromatin patterns and identified additional loci-with no Zelda binding-that show similar chromatin patterns, resulting with hundreds of Zelda-independent putative enhancers. These regions were found to be enriched with GAGA factor (GAF, Trl) and are typically located near early developmental zygotic genes. Overall our analysis suggests that GAF, together with Zelda, plays an important role in activating the zygotic genome. As we show, our computational approach offers an efficient algorithm for characterizing chromatin signatures around some loci of interest and allows a genome-wide identification of additional loci with similar chromatin patterns.

  8. Genome-wide and interaction linkage scan for nonsyndromic cleft lip with or without cleft palate in two multiplex families in Shenyang, China.

    PubMed

    Wang, Yun; Li, Xin; Zhu, Wen-Li; Guo, Jin-Zhen; Song, Xiao-Ming; Li, Shu-Qin; Li, Yong

    2010-10-01

    To identify the loci involved in nonsyndromic cleft lip with or without cleft palate (NSCL/P) in Northern Chinese people in Shenyang by using genomewide and interaction linkage scan. Two multiplex families in Shenyang from North China were ascertained through probands with NSCL/P. Blood of every member was drawn for DNA extraction and analysis. Genotypes were available for 382 autosomal short tandem repeat (STR) markers from the ABI Prism Linkage Mapping Set version 2.5. Linkage between markers and NSCL/P was assessed by 2-point parametric LOD scores, multipoint-heterogeneity parametric LOD scores (HLODs), and multipoint nonparametric linkage score (NPL). The initial scan suggested linkage on Chromosomes 1, 2, and 15. In subsequent fine mapping, 1q32-q42 showed a maximum multipoint LOD score of 1.9(empirical P=0.013) and an NPL score of 2.35 (empirical P=0.053). For 2p24-p25, the multipoint NPL increased to 2.94 (empirical P=0.007). 2-locus interaction analysis obtained a maximum NPL score of 3.73 (P=0.00078) and a maximum LOD score of 3 for Chromosome 1 (at 221 cM) and Chromosome 2 (at 29 cM). Both parametric and nonparametric linkage scores greatly increased over the initial linkage scores on 1q32-q42, suggesting a susceptibility locus in this region. Nonparametric linkage gave a strong evidence for a candidate region on chromosome 2p24-p25. The superiority of 2-locus linkage scores compared to single-locus scores gave additional evidence for linkage on 1q32-q42 and 2p24-p25, and suggested that certain genes in the two regions may contribute to NCSL/P risks with interaction. Copyright © 2010 The Editorial Board of Biomedical and Environmental Sciences. Published by Elsevier B.V. All rights reserved.

  9. A genome-wide linkage analysis for the personality trait neuroticism in the Irish affected sib-pair study of alcohol dependence.

    PubMed

    Kuo, Po-Hsiu; Neale, Michael C; Riley, Brien P; Patterson, Diana G; Walsh, Dermot; Prescott, Carol A; Kendler, Kenneth S

    2007-06-05

    Neuroticism is a personality trait which reflects individual differences in emotional stability and vulnerability to stress and anxiety. Consistent evidence shows substantial genetic influences on variation in this trait. The present study seeks to identify regions containing susceptibility loci for neuroticism using a selected sib-pair sample from Ireland. Using Merlin regress, we conducted a 4 cM whole-genome linkage analysis on 714 sib-pairs. Evidence for linkage to neuroticism was found on chromosomes 11p, 12q, and 15q. The highest linkage peak was on 12q at marker D12S1638 with a Lod score of 2.13 (-log p = 2.76, empirical P-value <0.001). Our data also support gender specific loci for neuroticism, with male specific linkage regions on chromosomes 1, 4, 11, 12, 15, 16, and 22, and female specific linkage regions on chromosomes 2, 4, 9, 12, 13, and 18. Some genome regions reported in the present study replicate findings from previous linkage studies of neuroticism. These results, together with prior studies, indicate several potential regions for quantitative trait loci for neuroticism that warrant further study.

  10. Genome-Wide Linkage Screen for Systolic Blood Pressure in the Veterans Administration Genetic Epidemiology Study (VAGES) of Mexican-Americans and Confirmation of a Major Susceptibility Locus on Chromosome 6q14.1

    PubMed Central

    Puppala, Sobha; Coletta, Dawn K.; Schneider, Jennifer; Hu, Shirley L.; Farook, Vidya S.; Dyer, Thomas D.; Arya, Rector; Blangero, John; Duggirala, Ravindranath; DeFronzo, Ralph A.; Jenkinson, Christopher P.

    2011-01-01

    Objective Hypertension or high blood pressure is a strong correlate of diseases such as obesity and type 2 diabetes. We conducted a genome-wide linkage screen to identify susceptibility genes influencing systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Mexican-Americans from the Veterans Administration Genetic Epidemiology Study (VAGES). Methods Using data from 1,089 individuals distributed across 266 families, we performed a multipoint linkage analysis to localize susceptibility loci for SBP and DBP by applying two models. In model 1, we added a sensible constant to the observed BP values in treated subjects [Tobin et al.; Stat Med 2005;24:2911–2935] to account for antihypertensive use (i.e. 15 and 10 mm Hg to SBP and DBP values, respectively). In model 2, we fixed values of 140 mm Hg for SBP and 90 mm Hg for DBP, if the treated values were less than the standard referenced treatment thresholds of 140/90 mm Hg for hypertensive status. However, if the observed treated BP values were found to be above these standard treatment thresholds, the actual observed treated BP values were retained in order not to reduce them by substitution of the treatment threshold values. Results The multipoint linkage analysis revealed strong linkage signals for SBP compared with DBP. The strongest evidence for linkage of SBP (model 1, LOD = 5.0; model 2, LOD = 3.6) was found on chromosome 6q14.1 near the marker D6S1031 (89 cM) in both models. In addition, some evidence for SBP linkage occurred on chromosomes 1q, 4p, and 16p. Most importantly, our major SBP linkage finding on chromosome 6q near marker D6S1031 was independently confirmed in a Caucasian population (LOD = 3.3). In summary, our study found evidence for a major locus on chromosome 6q influencing SBP levels in Mexican-Americans. PMID:21293138

  11. AnABlast: a new in silico strategy for the genome-wide search of novel genes and fossil regions

    PubMed Central

    Jimenez, Juan; Duncan, Caia D. S.; Gallardo, María; Mata, Juan; Perez-Pulido, Antonio J.

    2015-01-01

    Genome annotation, assisted by computer programs, is one of the great advances in modern biology. Nevertheless, the in silico identification of small and complex coding sequences is still challenging. We observed that amino acid sequences inferred from coding—but rarely from non-coding—DNA sequences accumulated alignments in low-stringency BLAST searches, suggesting that this alignments accumulation could be used to highlight coding regions in sequenced DNA. To investigate this possibility, we developed a computer program (AnABlast) that generates profiles of accumulated alignments in query amino acid sequences using a low-stringency BLAST strategy. To validate this approach, all six-frame translations of DNA sequences between every two annotated exons of the fission yeast genome were analysed with AnABlast. AnABlast-generated profiles identified three new copies of known genes, and four new genes supported by experimental evidence. New pseudogenes, ancestral carboxyl- and amino-terminal subtractions, complex gene rearrangements, and ancient fragments of mitDNA and of bacterial origin, were also inferred. Thus, this novel in silico approach provides a powerful tool to uncover new genes, as well as fossil-coding sequences, thus providing insight into the evolutionary history of annotated genomes. PMID:26494834

  12. Genome Wide Association Studies

    NASA Astrophysics Data System (ADS)

    Sebastiani, Paola; Solovieff, Nadia

    The availability of high throughput technology for parallel genotyping has opened the field of genetics to genome-wide association studies (GWAS). These studies generate massive amount of genetic data that challenge investigators with issues related to data management, statistical analysis of large data sets, visualization, and annotation of results. We will review the common approach to analysis of GWAS data and then discuss options to learn more from these data.

  13. A Sequence-Anchored Linkage Map of the Plant–Parasitic Nematode Meloidogyne hapla Reveals Exceptionally High Genome-Wide Recombination

    PubMed Central

    Thomas, Varghese P.; Fudali, Sylwia L.; Schaff, Jennifer E.; Liu, Qingli; Scholl, Elizabeth H.; Opperman, Charles H.; Bird, David McK; Williamson, Valerie M.

    2012-01-01

    Root-knot nematodes (Meloidogyne spp.) cause major yield losses to many of the world’s crops, but efforts to understand how these pests recognize and interact with their hosts have been hampered by a lack of genetic resources. Starting with progeny of a cross between inbred strains (VW8 and VW9) of Meloidogyne hapla that differed in host range and behavioral traits, we exploited the novel, facultative meiotic parthenogenic reproductive mode of this species to produce a genetic linkage map. Molecular markers were derived from SNPs identified between the sequenced and annotated VW9 genome and de novo sequence of VW8. Genotypes were assessed in 183 F2 lines. The colinearity of the genetic and physical maps supported the veracity of both. Analysis of local crossover intervals revealed that the average recombination rate is exceptionally high compared with that in other metazoans. In addition, F2 lines are largely homozygous for markers flanking crossover points, and thus resemble recombinant inbred lines. We suggest that the unusually high recombination rate may be an adaptation to generate within-population genetic diversity in this organism. This work presents the most comprehensive linkage map of a parasitic nematode to date and, together with genomic and transcript sequence resources, empowers M. hapla as a tractable model. Alongside the molecular map, these progeny lines can be used for analyses of genome organization and the inheritance of phenotypic traits that have key functions in modulating parasitism, behavior, and survival and for the eventual identification of the responsible genes. PMID:22870404

  14. Genome-Wide SNP Linkage Mapping and QTL Analysis for Fiber Quality and Yield Traits in the Upland Cotton Recombinant Inbred Lines Population

    PubMed Central

    Li, Cong; Dong, Yating; Zhao, Tianlun; Li, Ling; Li, Cheng; Yu, En; Mei, Lei; Daud, M. K.; He, Qiuling; Chen, Jinhong; Zhu, Shuijin

    2016-01-01

    It is of significance to discover genes related to fiber quality and yield traits and tightly linked markers for marker-assisted selection (MAS) in cotton breeding. In this study, 188 F8 recombinant inbred lines (RILs), derived from a intraspecific cross between HS46 and MARCABUCAG8US-1-88 were genotyped by the cotton 63K single nucleotide polymorphism (SNP) assay. Field trials were conducted in Sanya, Hainan Province, during the 2014–2015 cropping seasons under standard conditions. Results revealed significant differences (P < 0.05) among RILs, environments and replications for fiber quality and yield traits. Broad-sense heritabilities of all traits including fiber length, fiber uniformity, micronaire, fiber elongation, fiber strength, boll weight, and lint percentage ranged from 0.26 to 0.66. A 1784.28 cM (centimorgans) linkage map, harboring 2618 polymorphic SNP markers, was constructed, which had 0.68 cM per marker density. Seventy-one quantitative trait locus (QTLs) for fiber quality and yield traits were detected on 21 chromosomes, explaining 4.70∼32.28% phenotypic variance, in which 16 were identified as stable QTLs across two environments. Meanwhile, 12 certain regions were investigated to be involved in the control of one (hotspot) or more (cluster) traits, mainly focused on Chr05, Chr09, Chr10, Chr14, Chr19, and Chr20. Nineteen pairs of epistatic QTLs (e-QTLs) were identified, of which two pairs involved in two additive QTLs. These additive QTLs, e-QTLs, and QTL clusters were tightly linked to SNP markers, which may serve as target regions for map-based cloning, gene discovery, and MAS in cotton breeding. PMID:27660632

  15. RNA-seq based SNPs in some agronomically important oleiferous lines of Brassica rapa and their use for genome-wide linkage mapping and specific-region fine mapping.

    PubMed

    Paritosh, Kumar; Yadava, Satish K; Gupta, Vibha; Panjabi-Massand, Priya; Sodhi, Yashpal S; Pradhan, Akshay K; Pental, Deepak

    2013-07-09

    Brassica rapa (AA) contains very diverse forms which include oleiferous types and many vegetable types. Genome sequence of B. rapa line Chiifu (ssp. pekinensis), a leafy vegetable type, was published in 2011. Using this knowledge, it is important to develop genomic resources for the oleiferous types of B. rapa. This will allow more involved molecular mapping, in-depth study of molecular mechanisms underlying important agronomic traits and introgression of traits from B. rapa to major oilseed crops - B. juncea (AABB) and B. napus (AACC). The study explores the availability of SNPs in RNA-seq generated contigs of three oleiferous lines of B. rapa - Candle (ssp. oleifera, turnip rape), YSPB-24 and Tetra (ssp. trilocularis, Yellow sarson) and their use in genome-wide linkage mapping and specific-region fine mapping using a RIL population between Chiifu and Tetra. RNA-seq was carried out on the RNA isolated from young inflorescences containing unopened floral buds, floral axis and small leaves, using Illumina paired-end sequencing technology. Sequence assembly was carried out using the Velvet de-novo programme and the assembled contigs were organised against Chiifu gene models, available in the BRAD-CDS database. RNA-seq confirmed the presence of more than 17,000 single-copy gene models described in the BRAD database. The assembled contigs and the BRAD gene models were analyzed for the presence of SSRs and SNPs. While the number of SSRs was limited, more than 0.2 million SNPs were observed between Chiifu and the three oleiferous lines. Assays for SNPs were designed using KASPar technology and tested on a F7-RIL population derived from a Chiifu x Tetra cross. The design of the SNP assays were based on three considerations - the 50 bp flanking region of the SNPs should be strictly similar, the SNP should have a read-depth of ≥7 and no exon/intron junction should be present within the 101 bp target region. Using these criteria, a total of 640 markers (580 for genome-wide

  16. Genetic Diversity, Population Structure, and Linkage Disequilibrium of a Core Collection of Ziziphus jujuba Assessed with Genome-wide SNPs Developed by Genotyping-by-sequencing and SSR Markers

    PubMed Central

    Chen, Wu; Hou, Lu; Zhang, Zhiyong; Pang, Xiaoming; Li, Yingyue

    2017-01-01

    Chinese jujube (Ziziphus jujuba Mill) is an economically important fruit species native to China with high nutritious and medicinal value. Genotyping-by-sequencing was used to detect and genotype single nucleotide polymorphisms (SNPs) in a core collection of 150 Chinese jujube accessions and further to characterize their genetic diversity, population structure, and linkage disequilibrium (LD). A total of 4,680 high-quality SNPs were identified, of which 38 sets of tri-allelic SNPs were detected. The average polymorphism information content (PIC) values based on bi-allelic SNPs and tri-allelic SNPs were 0.27 and 0.38, respectively. STRUCTURE and principal coordinate analyses based on SNPs revealed that the 150 accessions could be clustered into two groups. However, neighbor-joining trees indicated the accessions should be grouped into three major clusters. Our data confirm that the resolving power for genetic diversity was similar for the SSRs and SNPs. In contrast, regarding population structure, the resolving power was higher for SSRs than for SNPs. The LD pattern in Chinese jujube was investigated for the first time. We observed a relatively rapid LD decay with a short range (∼10 kb) for all pseudo-chromosomes and for individual pseudo-chromosomes. Our findings provide important information for future genome-wide association analyses and marker-assisted selective breeding of Chinese jujube. PMID:28458680

  17. Genetic Diversity, Population Structure, and Linkage Disequilibrium of a Core Collection of Ziziphus jujuba Assessed with Genome-wide SNPs Developed by Genotyping-by-sequencing and SSR Markers.

    PubMed

    Chen, Wu; Hou, Lu; Zhang, Zhiyong; Pang, Xiaoming; Li, Yingyue

    2017-01-01

    Chinese jujube (Ziziphus jujuba Mill) is an economically important fruit species native to China with high nutritious and medicinal value. Genotyping-by-sequencing was used to detect and genotype single nucleotide polymorphisms (SNPs) in a core collection of 150 Chinese jujube accessions and further to characterize their genetic diversity, population structure, and linkage disequilibrium (LD). A total of 4,680 high-quality SNPs were identified, of which 38 sets of tri-allelic SNPs were detected. The average polymorphism information content (PIC) values based on bi-allelic SNPs and tri-allelic SNPs were 0.27 and 0.38, respectively. STRUCTURE and principal coordinate analyses based on SNPs revealed that the 150 accessions could be clustered into two groups. However, neighbor-joining trees indicated the accessions should be grouped into three major clusters. Our data confirm that the resolving power for genetic diversity was similar for the SSRs and SNPs. In contrast, regarding population structure, the resolving power was higher for SSRs than for SNPs. The LD pattern in Chinese jujube was investigated for the first time. We observed a relatively rapid LD decay with a short range (∼10 kb) for all pseudo-chromosomes and for individual pseudo-chromosomes. Our findings provide important information for future genome-wide association analyses and marker-assisted selective breeding of Chinese jujube.

  18. In Search of Genes Associated with Risk for Psychopathic Tendencies in Children: A Two-Stage Genome-Wide Association Study of Pooled DNA

    ERIC Educational Resources Information Center

    Viding, Essi; Hanscombe, Ken B.; Curtis, Charles J. C.; Davis, Oliver S. P.; Meaburn, Emma L.; Plomin, Robert

    2010-01-01

    Background: Quantitative genetic data from our group indicates that antisocial behaviour (AB) is strongly heritable when coupled with psychopathic, callous-unemotional (CU) personality traits. We have also demonstrated that the genetic influences for AB and CU overlap considerably. We conducted a genome-wide association scan that capitalises on…

  19. In Search of Genes Associated with Risk for Psychopathic Tendencies in Children: A Two-Stage Genome-Wide Association Study of Pooled DNA

    ERIC Educational Resources Information Center

    Viding, Essi; Hanscombe, Ken B.; Curtis, Charles J. C.; Davis, Oliver S. P.; Meaburn, Emma L.; Plomin, Robert

    2010-01-01

    Background: Quantitative genetic data from our group indicates that antisocial behaviour (AB) is strongly heritable when coupled with psychopathic, callous-unemotional (CU) personality traits. We have also demonstrated that the genetic influences for AB and CU overlap considerably. We conducted a genome-wide association scan that capitalises on…

  20. A genome-wide search for eigenetically regulated genes in zebra finch using MethylCap-seq and RNA-seq

    PubMed Central

    Steyaert, Sandra; Diddens, Jolien; Galle, Jeroen; De Meester, Ellen; De Keulenaer, Sarah; Bakker, Antje; Sohnius-Wilhelmi, Nina; Frankl-Vilches, Carolina; Van der Linden, Annemie; Van Criekinge, Wim; Vanden Berghe, Wim; De Meyer, Tim

    2016-01-01

    Learning and memory formation are known to require dynamic CpG (de)methylation and gene expression changes. Here, we aimed at establishing a genome-wide DNA methylation map of the zebra finch genome, a model organism in neuroscience, as well as identifying putatively epigenetically regulated genes. RNA- and MethylCap-seq experiments were performed on two zebra finch cell lines in presence or absence of 5-aza-2′-deoxycytidine induced demethylation. First, the MethylCap-seq methodology was validated in zebra finch by comparison with RRBS-generated data. To assess the influence of (variable) methylation on gene expression, RNA-seq experiments were performed as well. Comparison of RNA-seq and MethylCap-seq results showed that at least 357 of the 3,457 AZA-upregulated genes are putatively regulated by methylation in the promoter region, for which a pathway analysis showed remarkable enrichment for neurological networks. A subset of genes was validated using Exon Arrays, quantitative RT-PCR and CpG pyrosequencing on bisulfite-treated samples. To our knowledge, this study provides the first genome-wide DNA methylation map of the zebra finch genome as well as a comprehensive set of genes of which transcription is under putative methylation control. PMID:26864856

  1. Quantification of amylose, amylopectin, and β-glucan in search for genes controlling the three major quality traits in barley by genome-wide association studies.

    PubMed

    Shu, Xiaoli; Rasmussen, Søren K

    2014-01-01

    Genome-wide association studies (GWAS) for amylose, amylopectin and β-glucan concentration in a collection of 254 European spring barley varieties allowed to identify 20, 17, and 21 single nucleotide polymorphic (SNP) markers, respectively, associated with these important grain quality traits. Negative correlations between the content of amylose and β-glucan (R = -0.62, P < 0.01) and amylopectin and β-glucan (R = -0.487, P < 0.01) were found in this large collection of spring barley varieties. Besides HvCslF6, amo1 and AGPL2, sex6, and waxy were identified among the major genes responsible for β-glucan, amylose and amylopectin content, respectively. Several minor genes like HvGSL4, HvGSL3, and HvCesA6, PWD were also detected by GWAS for the first time. Furthermore, the gene encoding β-fructofuranosidase, located on the short arm of chromosome 7H at 1.49 cM, and SRF6, encoding "leucine-rich repeat receptor kinase protein" on chromosome 2 H, are proposed to be new candidate genes for amylopectin formation in barley endosperm. Several of the associated SNPs on chromosome 1, 5, 6, and 7H mapped to overlapping regions containing QTLs and genes controlling the three grain constituents. In particular chromosomes 5 and 7H carry many QTLs controlling barley grain quality. Amylose, amylopectin and β-glucan were interacted among each other through a metabolic network connected by UDP showing pleiotropic effects. Taken together, these results showed that cereal quality traits related each other and regulated through an interaction network, the identified major genes and genetic regions for amylose, amylopectin and β-glucan is a helpful for further research on carbohydrates and barley breeding.

  2. Quantification of amylose, amylopectin, and β-glucan in search for genes controlling the three major quality traits in barley by genome-wide association studies

    PubMed Central

    Shu, Xiaoli; Rasmussen, Søren K.

    2014-01-01

    Genome-wide association studies (GWAS) for amylose, amylopectin and β-glucan concentration in a collection of 254 European spring barley varieties allowed to identify 20, 17, and 21 single nucleotide polymorphic (SNP) markers, respectively, associated with these important grain quality traits. Negative correlations between the content of amylose and β-glucan (R = −0.62, P < 0.01) and amylopectin and β-glucan (R = −0.487, P < 0.01) were found in this large collection of spring barley varieties. Besides HvCslF6, amo1 and AGPL2, sex6, and waxy were identified among the major genes responsible for β-glucan, amylose and amylopectin content, respectively. Several minor genes like HvGSL4, HvGSL3, and HvCesA6, PWD were also detected by GWAS for the first time. Furthermore, the gene encoding β-fructofuranosidase, located on the short arm of chromosome 7H at 1.49 cM, and SRF6, encoding “leucine-rich repeat receptor kinase protein” on chromosome 2 H, are proposed to be new candidate genes for amylopectin formation in barley endosperm. Several of the associated SNPs on chromosome 1, 5, 6, and 7H mapped to overlapping regions containing QTLs and genes controlling the three grain constituents. In particular chromosomes 5 and 7H carry many QTLs controlling barley grain quality. Amylose, amylopectin and β-glucan were interacted among each other through a metabolic network connected by UDP showing pleiotropic effects. Taken together, these results showed that cereal quality traits related each other and regulated through an interaction network, the identified major genes and genetic regions for amylose, amylopectin and β-glucan is a helpful for further research on carbohydrates and barley breeding. PMID:24860587

  3. Integration of Genome-Wide Computation DRE Search, AhR ChIP-chip and Gene Expression Analyses of TCDD-Elicited Responses in the Mouse Liver

    PubMed Central

    2011-01-01

    Background The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor (TF) that mediates responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Integration of TCDD-induced genome-wide AhR enrichment, differential gene expression and computational dioxin response element (DRE) analyses further elucidate the hepatic AhR regulatory network. Results Global ChIP-chip and gene expression analyses were performed on hepatic tissue from immature ovariectomized mice orally gavaged with 30 μg/kg TCDD. ChIP-chip analysis identified 14,446 and 974 AhR enriched regions (1% false discovery rate) at 2 and 24 hrs, respectively. Enrichment density was greatest in the proximal promoter, and more specifically, within ± 1.5 kb of a transcriptional start site (TSS). AhR enrichment also occurred distal to a TSS (e.g. intergenic DNA and 3' UTR), extending the potential gene expression regulatory roles of the AhR. Although TF binding site analyses identified over-represented DRE sequences within enriched regions, approximately 50% of all AhR enriched regions lacked a DRE core (5'-GCGTG-3'). Microarray analysis identified 1,896 number of TCDD-responsive genes (|fold change| ≥ 1.5, P1(t) > 0.999). Integrating this gene expression data with our ChIP-chip and DRE analyses only identified 625 differentially expressed genes that involved an AhR interaction at a DRE. Functional annotation analysis of differentially regulated genes associated with AhR enrichment identified overrepresented processes related to fatty acid and lipid metabolism and transport, and xenobiotic metabolism, which are consistent with TCDD-elicited steatosis in the mouse liver. Conclusions Details of the AhR regulatory network have been expanded to include AhR-DNA interactions within intragenic and intergenic genomic regions. Moreover, the AhR can interact with DNA independent of a DRE core suggesting there are alternative mechanisms of AhR-mediated gene regulation. PMID:21762485

  4. Replication in genome-wide association studies

    PubMed Central

    Kraft, Peter; Zeggini, Eleftheria; Ioannidis, John P. A.

    2009-01-01

    Summary Replication helps ensure that a genotype-phenotype association observed in a genome-wide association (GWA) study represents a credible association and is not a chance finding or an artifact due to uncontrolled biases. We discuss prerequisites for exact replication; issues of heterogeneity; advantages and disadvantages of different methods of data synthesis across multiple studies; frequentist vs. Bayesian inferences for replication; and challenges that arise from multi-team collaborations. While consistent replication can greatly improve the credibility of a genotype-phenotype association, it may not eliminate spurious associations due to biases shared by many studies. Conversely, lack of replication in well-powered follow-up studies usually invalidates the initially proposed association, although occasionally it may point to differences in linkage disequilibrium or effect modifiers across studies. PMID:20454541

  5. Genome-wide association study of working memory brain activation.

    PubMed

    Blokland, Gabriëlla A M; Wallace, Angus K; Hansell, Narelle K; Thompson, Paul M; Hickie, Ian B; Montgomery, Grant W; Martin, Nicholas G; McMahon, Katie L; de Zubicaray, Greig I; Wright, Margaret J

    2017-05-01

    In a population-based genome-wide association (GWA) study of n-back working memory task-related brain activation, we extracted the average percent BOLD signal change (2-back minus 0-back) from 46 regions-of-interest (ROIs) in functional MRI scans from 863 healthy twins and siblings. ROIs were obtained by creating spheres around group random effects analysis local maxima, and by thresholding a voxel-based heritability map of working memory brain activation at 50%. Quality control for test-retest reliability and heritability of ROI measures yielded 20 reliable (r>0.7) and heritable (h(2)>20%) ROIs. For GWA analysis, the cohort was divided into a discovery (n=679) and replication (n=97) sample. No variants survived the stringent multiple-testing-corrected genome-wide significance threshold (p<4.5×10(-9)), or were replicated (p<0.0016), but several genes were identified that are worthy of further investigation. A search of 529,379 genomic markers resulted in discovery of 31 independent single nucleotide polymorphisms (SNPs) associated with BOLD signal change at a discovery level of p<1×10(-5). Two SNPs (rs7917410 and rs7672408) were associated at a significance level of p<1×10(-7). Only one, most strongly affecting BOLD signal change in the left supramarginal gyrus (R(2)=5.5%), had multiple SNPs associated at p<1×10(-5) in linkage disequilibrium with it, all located in and around the BANK1 gene. BANK1 encodes a B-cell-specific scaffold protein and has been shown to negatively regulate CD40-mediated AKT activation. AKT is part of the dopamine-signaling pathway, suggesting a mechanism for the involvement of BANK1 in the BOLD response to working memory. Variants identified here may be relevant to (the susceptibility to) common disorders affecting brain function. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Genome-wide scan of bipolar disorder and investigation of population stratification effects on linkage: support for susceptibility loci at 4q21, 7q36, 9p21, 12q24, 14q24, and 16p13.

    PubMed

    Cassidy, F; Zhao, C; Badger, J; Claffey, E; Dobrin, S; Roche, S; McKeon, P

    2007-09-05

    Bipolar disorder (BPD) is a complex genetic disorder with cycling symptoms of depression and mania. Despite the extreme complexity of this psychiatric disorder, attempts to localize genes which confer vulnerability to the disorder have had some success. Chromosomal regions including 4p16, 12q24, 18p11, 18q22, and 21q21 have been repeatedly linked to BPD in different populations. Here we present the results of a whole genome scan for linkage to BPD in an Irish population. Our most significant result was at 14q24 which yielded a non-parametric LOD (NPL) score of 3.27 at the D14S588 marker with a nominal P-value of 0.0006 under a narrow (bipolar type I only) model of affection. We previously reported linkage to 14q22-24 in a subset of the families tested in this analysis. We also obtained suggestive evidence for linkage at 4q21, 9p21, 12q24, and 16p13, chromosomal regions that have all been previously linked to BPD. Additionally, we report on a novel approach to linkage analysis, STRUCTURE-Guided Linkage Analysis (SGLA), which is designed to reduce genetic heterogeneity and increase the power to detect linkage. Application of this technique resulted in more highly significant evidence for linkage of BPD to three regions including 16p13, a locus that has been repeatedly linked to numerous psychiatric disorders.

  7. Patterns of Genome-Wide VDR Locations

    PubMed Central

    Tuoresmäki, Pauli; Väisänen, Sami; Neme, Antonio

    2014-01-01

    The genome-wide analysis of the binding sites of the transcription factor vitamin D receptor (VDR) is essential for a global appreciation the physiological impact of the nuclear hormone 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). Genome-wide analysis of lipopolysaccharide (LPS)-polarized THP-1 human monocytic leukemia cells via chromatin immunoprecipitation sequencing (ChIP-seq) resulted in 1,318 high-confidence VDR binding sites, of which 789 and 364 occurred uniquely with and without 1,25(OH)2D3 stimulation, while only 165 were common. We re-analyzed five public VDR ChIP-seq datasets with identical peak calling settings (MACS, version 2) and found, using a novel consensus summit identification strategy, in total 23,409 non-overlapping VDR binding sites, 75% of which are unique within the six analyzed cellular models. LPS-differentiated THP-1 cells have 22% more genomic VDR locations than undifferentiated cells and both cell types display more overlap in their VDR locations than the other investigated cell types. In general, the intersection of VDR binding profiles of ligand-stimulated cells is higher than those of unstimulated cells. De novo binding site searches and HOMER screening for binding motifs formed by direct repeats spaced by three nucleotides (DR3) suggest for all six VDR ChIP-seq datasets that these sequences are found preferentially at highly ligand responsive VDR loci. Importantly, all VDR ChIP-seq datasets display the same relationship between the VDR occupancy and the percentage of DR3-type sequences below the peak summits. The comparative analysis of six VDR ChIP-seq datasets demonstrated that the mechanistic basis for the action of the VDR is independent of the cell type. Only the minority of genome-wide VDR binding sites contains a DR3-type sequence. Moreover, the total number of identified VDR binding sites in each ligand-stimulated cell line inversely correlates with the percentage of peak summits with DR3 sites. PMID:24787735

  8. Genome-Wide Linkage Scan of Bipolar Disorder in a Colombian Population Isolate Replicates Loci on Chromosomes 7p21–22, 1p31, 16p12 and 21q21–22 and Identifies a Novel Locus on Chromosome 12q

    PubMed Central

    Kremeyer, B.; García, J.; Müller, H.; Burley, M.W.; Herzberg, I.; Parra, M.V.; Duque, C.; Vega, J.; Montoya, P.; López, M.C.; Bedoya, G.; Reus, V.; Palacio, C.; López, C.; Ospina-Duque, J.; Freimer, N.B.; Ruiz-Linares, A.

    2011-01-01

    Background/Aims: Bipolar disorder (BP) is a severe psychiatric illness, characterised by alternating episodes of depression and mania, which ranks among the top ten causes of morbidity and life-long disability world-wide. We have previously performed a whole-genome linkage scan on 6 pedigrees segregating severe BP from the well-characterised population isolate of Antioquia, Colombia. We recently collected genotypes for the same set of 382 autosomal microsatellite markers in 9 additional Antioquian BP pedigrees. Here, we report the analysis of the combined pedigree set. Methods: Linkage analysis using both parametric and nonparametric approaches was conducted for 3 different diagnostic models: severe BP only (BPI); mood disorders (BPI, BPII and major depression); and psychosis (operationally defined by the occurrence of at least 1 episode of hallucinations and/or delusions). Results and Conclusion: For BPI only, the most interesting result was obtained for chromosome 7p21.1–p22.2 under a recessive model of inheritance (heterogeneity LOD score = 2.80), a region that had previously been linked to BP in a study on Portuguese Island families. For both BPI and mood disorders, nonparametric analyses identified a locus on chromosome 12ct–q14 (nonparametric linkage = 2.55 and 2.35, respectively). This locus has not previously been reported as a candidate region for BP. Additional candidate regions were found on chromosomes 1p22–31 (mood disorders) and 21q21–22 (BPI), 2 loci that have repeatedly been implicated in BP susceptibility. Linkage analysis of psychosis as a phenotype identified candidate regions on chromosomes 2q24–31 and 16p12–q12. The finding on chromosome 16p is noteworthy because the same locus has been implicated by genome-wide association analyses of BP. PMID:21071953

  9. Genome-Wide Linkage Mapping of QTL for Yield Components, Plant Height and Yield-Related Physiological Traits in the Chinese Wheat Cross Zhou 8425B/Chinese Spring

    PubMed Central

    Gao, Fengmei; Wen, Weie; Liu, Jindong; Rasheed, Awais; Yin, Guihong; Xia, Xianchun; Wu, Xiaoxia; He, Zhonghu

    2015-01-01

    Identification of genes for yield components, plant height (PH), and yield-related physiological traits and tightly linked molecular markers is of great importance in marker-assisted selection (MAS) in wheat breeding. In the present study, 246 F8 RILs derived from the cross of Zhou 8425B/Chinese Spring were genotyped using the high-density Illumina iSelect 90K single nucleotide polymorphism (SNP) assay. Field trials were conducted at Zhengzhou and Zhoukou of Henan Province, during the 2012–2013 and 2013–2014 cropping season under irrigated conditions, providing data for four environments. Analysis of variance (ANOVA) of agronomic and physiological traits revealed significant differences (P < 0.01) among RILs, environments, and RILs × environments interactions. Broad-sense heritabilities of all traits including thousand kernel weight (TKW), PH, spike length (SL), kernel number per spike (KNS), spike number/m2 (SN), normalized difference in vegetation index at anthesis (NDVI-A) and at 10 days post-anthesis (NDVI-10), SPAD value of chlorophyll content at anthesis (Chl-A) and at 10 days post-anthesis (Chl-10) ranged between 0.65 and 0.94. A linkage map spanning 3609.4 cM was constructed using 5636 polymorphic SNP markers, with an average chromosome length of 171.9 cM and marker density of 0.64 cM/marker. A total of 866 SNP markers were newly mapped to the hexaploid wheat linkage map. Eighty-six QTL for yield components, PH, and yield-related physiological traits were detected on 18 chromosomes except 1D, 5D, and 6D, explaining 2.3–33.2% of the phenotypic variance. Ten stable QTL were identified across four environments, viz. QTKW.caas-6A.1, QTKW.caas-7AL, QKNS.caas-4AL, QSN.caas-1AL.1, QPH.caas-4BS.2, QPH.caas-4DS.1, QSL.caas-4AS, QSL.caas-4AL.1, QChl-A.caas-5AL, and QChl-10.caas-5BL. Meanwhile, 10 QTL-rich regions were found on chromosome 1BS, 2AL (2), 3AL, 4AL (2), 4BS, 4DS, 5BL, and 7AL exhibiting pleiotropic effects. These QTL or QTL clusters are tightly

  10. A novel statistic for genome-wide interaction analysis.

    PubMed

    Wu, Xuesen; Dong, Hua; Luo, Li; Zhu, Yun; Peng, Gang; Reveille, John D; Xiong, Momiao

    2010-09-23

    Although great progress in genome-wide association studies (GWAS) has been made, the significant SNP associations identified by GWAS account for only a few percent of the genetic variance, leading many to question where and how we can find the missing heritability. There is increasing interest in genome-wide interaction analysis as a possible source of finding heritability unexplained by current GWAS. However, the existing statistics for testing interaction have low power for genome-wide interaction analysis. To meet challenges raised by genome-wide interactional analysis, we have developed a novel statistic for testing interaction between two loci (either linked or unlinked). The null distribution and the type I error rates of the new statistic for testing interaction are validated using simulations. Extensive power studies show that the developed statistic has much higher power to detect interaction than classical logistic regression. The results identified 44 and 211 pairs of SNPs showing significant evidence of interactions with FDR<0.001 and 0.001genome-wide interaction analysis is a valuable tool for finding remaining missing heritability unexplained by the current GWAS, and the developed novel statistic is able to search significant interaction between SNPs across the genome. Real data analysis showed that the results of genome-wide interaction analysis can be replicated in two independent studies.

  11. Genome-Wide Association Study of Schizophrenia in Japanese Population

    PubMed Central

    Yamada, Kazuo; Iwayama, Yoshimi; Hattori, Eiji; Iwamoto, Kazuya; Toyota, Tomoko; Ohnishi, Tetsuo; Ohba, Hisako; Maekawa, Motoko; Kato, Tadafumi; Yoshikawa, Takeo

    2011-01-01

    Schizophrenia is a devastating neuropsychiatric disorder with genetically complex traits. Genetic variants should explain a considerable portion of the risk for schizophrenia, and genome-wide association study (GWAS) is a potentially powerful tool for identifying the risk variants that underlie the disease. Here, we report the results of a three-stage analysis of three independent cohorts consisting of a total of 2,535 samples from Japanese and Chinese populations for searching schizophrenia susceptibility genes using a GWAS approach. Firstly, we examined 115,770 single nucleotide polymorphisms (SNPs) in 120 patient-parents trio samples from Japanese schizophrenia pedigrees. In stage II, we evaluated 1,632 SNPs (1,159 SNPs of p<0.01 and 473 SNPs of p<0.05 that located in previously reported linkage regions). The second sample consisted of 1,012 case-control samples of Japanese origin. The most significant p value was obtained for the SNP in the ELAVL2 [(embryonic lethal, abnormal vision, Drosophila)-like 2] gene located on 9p21.3 (p = 0.00087). In stage III, we scrutinized the ELAVL2 gene by genotyping gene-centric tagSNPs in the third sample set of 293 family samples (1,163 individuals) of Chinese descent and the SNP in the gene showed a nominal association with schizophrenia in Chinese population (p = 0.026). The current data in Asian population would be helpful for deciphering ethnic diversity of schizophrenia etiology. PMID:21674006

  12. Genome-wide significant loci for addiction and anxiety

    PubMed Central

    Hodgson, K.; Almasy, L.; Knowles, E.E.M.; Kent, J.W.; Curran, J.E.; Dyer, T.D.; Göring, H.H.H.; Olvera, R.L.; Fox, P.T.; Pearlson, G.D.; Krystal, J.H.; Duggirala, R.; Blangero, J.; Glahn, D.C.

    2017-01-01

    Background Psychiatric comorbidity is common among individuals with addictive disorders, with patients frequently suffering from anxiety disorders. While the genetic architecture of comorbid addictive and anxiety disorders remains unclear, elucidating the genes involved could provide important insights into the underlying etiology. Methods Here we examine a sample of 1284 Mexican-Americans from randomly selected extended pedigrees. Variance decomposition methods were used to examine the role of genetics in addiction phenotypes (lifetime history of alcohol dependence, drug dependence or chronic smoking) and various forms of clinically relevant anxiety. Genome-wide univariate and bivariate linkage scans were conducted to localize the chromosomal regions influencing these traits. Results Addiction phenotypes and anxiety were shown to be heritable and univariate genome-wide linkage scans revealed significant quantitative trait loci for drug dependence (14q13.2–q21.2, LOD = 3.322) and a broad anxiety phenotype (12q24.32–q24.33, LOD = 2.918). Significant positive genetic correlations were observed between anxiety and each of the addiction subtypes (ρg = 0.550–0.655) and further investigation with bivariate linkage analyses identified significant pleiotropic signals for alcohol dependence-anxiety (9q33.1–q33.2, LOD = 3.054) and drug dependence-anxiety (18p11.23–p11.22, LOD = 3.425). Conclusions This study confirms the shared genetic underpinnings of addiction and anxiety and identifies genomic loci involved in the etiology of these comorbid disorders. The linkage signal for anxiety on 12q24 spans the location of TMEM132D, an emerging gene of interest from previous GWAS of anxiety traits, whilst the bivariate linkage signal identified for anxiety-alcohol on 9q33 peak coincides with a region where rare CNVs have been associated with psychiatric disorders. Other signals identified implicate novel regions of the genome in addiction genetics. PMID:27318301

  13. Developments in obesity genetics in the era of genome-wide association studies.

    PubMed

    Day, Felix R; Loos, Ruth J F

    2011-01-01

    Obesity is an important factor contributing to the global burden of morbidity and mortality. By identifying obesity susceptibility genes, scientists aim to elucidate some of its aetiology. Early studies used candidate gene and genome-wide linkage approaches to search for such genes with limited success. However, the advent of genome-wide association studies (GWAS) has dramatically increased the pace of gene discovery. So far, GWAS have identified at least 50 loci robustly associated with body mass index (BMI), waist-to-hip ratio, body fat percentage and extreme obesity. Some of these have been shown to replicate in non-white populations and in children and adolescents. Furthermore, for some loci interaction studies have shown that the BMI-increasing effect is attenuated in physically active individuals. Despite many successful discoveries, the effect sizes of the established loci are small, and combined they explain only a fraction of the inter-individual variation in BMI. The low predictive value means that their value in mainstream health care is limited. However, as most of these newly established loci were not previously linked to obesity, they may provide new insights into body weight regulation. Continued efforts in gene discovery, using a range of approaches, will be needed to increase our understanding of obesity. Copyright © 2011 S. Karger AG, Basel.

  14. Genome-wide differentiation of various melon horticultural groups for use in genome wide association study for fruit firmness and construction of a high resolution genetic map

    USDA-ARS?s Scientific Manuscript database

    We generated 13,789 single nucleotide plymorphism (SNP) markers from 97 melon accessions using genotyping by sequencing and anchored them to chromosomes to understand genome-wide fixation index between various melon morphotypes and linkage disequilibrium (LD) decay for inodorus and cantalupensis, th...

  15. Genome-wide association mapping in plants.

    PubMed

    George, Andrew W; Cavanagh, Colin

    2015-06-01

    We present new association mapping methods which address the unique challenges of analyzing genome-wide data from multi-environment plant studies. Association studies on a genome-wide scale are being performed in plants. Unlike human studies, plant studies contain replicates whose data may be recorded across different environments. Plant studies also often employ elaborate experimental designs for controlling extraneous phenotypic variation. As a result, the genome-wide analysis of data from plant studies can be challenging. In this paper, we present QK-based association mapping for the analysis of data from plant association studies. In doing so, we have developed: (a) a general multivariate QK framework for association mapping in plant studies of arbitrary complexity; (b) a new weighted two-stage analysis approach for QK-based association mapping; (c) a heuristic procedure for determining when two-stage analysis is appropriate; and (d) a Monte Carlo sampling procedure for controlling the genome-wide type I error rate. We conduct a simulation study to evaluate the performance of our genome-wide mapping technique. We also analyze data from a multi-environment association study in wheat.

  16. Genome-Wide Association Studies of Drug-Resistance Determinants.

    PubMed

    Volkman, Sarah K; Herman, Jonathan; Lukens, Amanda K; Hartl, Daniel L

    2017-03-01

    Population genetic strategies that leverage association, selection, and linkage have identified drug-resistant loci. However, challenges and limitations persist in identifying drug-resistance loci in malaria. In this review we discuss the genetic basis of drug resistance and the use of genome-wide association studies, complemented by selection and linkage studies, to identify and understand mechanisms of drug resistance and response. We also discuss the implications of nongenetic mechanisms of drug resistance recently reported in the literature, and present models of the interplay between nongenetic and genetic processes that contribute to the emergence of drug resistance. Throughout, we examine artemisinin resistance as an example to emphasize challenges in identifying phenotypes suitable for population genetic studies as well as complications due to multiple-factor drug resistance. Copyright © 2016. Published by Elsevier Ltd.

  17. Genome-wide association studies of cancer.

    PubMed

    Jorgenson, Eric; Witte, John S

    2007-08-01

    Genome-wide association studies provide a new and powerful approach to investigate the effect of inherited genetic variation on the risk of human disease. These studies rely on high throughput DNA microarray technology to genotype hundreds of thousands of genetic variants across the human genome. The first genome-wide association studies have identified previously unknown genetic risk factors that influence a range of diseases, including prostate cancer, breast cancer, myocardial infarction, age-related macular degeneration, diabetes, Crohn's disease and obesity. Many more studies are currently underway, including a number that will focus on other cancers (e.g., colorectal). Here we discuss the major issues involved in conducting genome-wide association studies and how these studies can be used to examine cancer phenotypes.

  18. Genome-wide scans for loci under selection in humans.

    PubMed

    Ronald, James; Akey, Joshua M

    2005-06-01

    Natural selection, which can be defined as the differential contribution of genetic variants to future generations, is the driving force of Darwinian evolution. Identifying regions of the human genome that have been targets of natural selection is an important step in clarifying human evolutionary history and understanding how genetic variation results in phenotypic diversity, it may also facilitate the search for complex disease genes. Technological advances in high-throughput DNA sequencing and single nucleotide polymorphism genotyping have enabled several genome-wide scans of natural selection to be undertaken. Here, some of the observations that are beginning to emerge from these studies will be reviewed, including evidence for geographically restricted selective pressures (ie local adaptation) and a relationship between genes subject to natural selection and human disease. In addition, the paper will highlight several important problems that need to be addressed in future genome-wide studies of natural selection.

  19. Genome-wide RNA Tomography in the zebrafish embryo.

    PubMed

    Junker, Jan Philipp; Noël, Emily S; Guryev, Victor; Peterson, Kevin A; Shah, Gopi; Huisken, Jan; McMahon, Andrew P; Berezikov, Eugene; Bakkers, Jeroen; van Oudenaarden, Alexander

    2014-10-23

    Advancing our understanding of embryonic development is heavily dependent on identification of novel pathways or regulators. Although genome-wide techniques such as RNA sequencing are ideally suited for discovering novel candidate genes, they are unable to yield spatially resolved information in embryos or tissues. Microscopy-based approaches, using in situ hybridization, for example, can provide spatial information about gene expression, but are limited to analyzing one or a few genes at a time. Here, we present a method where we combine traditional histological techniques with low-input RNA sequencing and mathematical image reconstruction to generate a high-resolution genome-wide 3D atlas of gene expression in the zebrafish embryo at three developmental stages. Importantly, our technique enables searching for genes that are expressed in specific spatial patterns without manual image annotation. We envision broad applicability of RNA tomography as an accurate and sensitive approach for spatially resolved transcriptomics in whole embryos and dissected organs.

  20. A genome-wide association study of antidepressant response in Koreans.

    PubMed

    Myung, W; Kim, J; Lim, S-W; Shim, S; Won, H-H; Kim, Seonwoo; Kim, Sangha; Lee, M-S; Chang, H S; Kim, J-W; Carroll, B J; Kim, D K

    2015-09-08

    We conducted a three-stage genome-wide association study (GWAS) of response to antidepressant drugs in an ethnically homogeneous sample of Korean patients in untreated episodes of nonpsychotic unipolar depression, mostly of mature onset. Strict quality control was maintained in case selection, diagnosis, verification of adherence and outcome assessments. Analyzed cases completed 6 weeks of treatment with adequate plasma drug concentrations. The overall successful completion rate was 85.5%. Four candidate single-nucleotide polymorphisms (SNPs) on three chromosomes were identified by genome-wide search in the discovery sample of 481 patients who received one of four allowed selective serotonin reuptake inhibitor (SSRI) antidepressant drugs (Stage 1). In a focused replication study of 230 SSRI-treated patients, two of these four SNP candidates were confirmed (Stage 2). Analysis of the Stage 1 and Stage 2 samples combined (n = 711) revealed GWAS significance (P = 1.60 × 10(-8)) for these two SNP candidates, which were in perfect linkage disequilibrium. These two significant SNPs were confirmed also in a focused cross-replication study of 159 patients treated with the non-SSRI antidepressant drug mirtazapine (Stage 3). Analysis of the Stage 1, Stage 2 and Stage 3 samples combined (n = 870) also revealed GWAS significance for these two SNPs, which was sustained after controlling for gender, age, number of previous episodes, age at onset and baseline severity (P = 3.57 × 10(-8)). For each SNP, the response rate decreased (odds ratio=0.31, 95% confidence interval: 0.20-0.47) as a function of the number of minor alleles (non-response alleles). The two SNPs significantly associated with antidepressant response are rs7785360 and rs12698828 of the AUTS2 gene, located on chromosome 7 in 7q11.22. This gene has multiple known linkages to human psychological functions and neurobehavioral disorders. Rigorous replication efforts in other ethnic populations are recommended.

  1. Utilizing the Dog Genome in the Search for Novel Candidate Genes Involved in Glioma Development—Genome Wide Association Mapping followed by Targeted Massive Parallel Sequencing Identifies a Strongly Associated Locus

    PubMed Central

    Dickinson, Peter; Xiong, Anqi; York, Daniel; Jayashankar, Kartika; Pielberg, Gerli; Koltookian, Michele; Murén, Eva; Fuxelius, Hans-Henrik; Weishaupt, Holger; Andersson, Göran; Hedhammar, Åke; Bongcam-Rudloff, Erik; Forsberg-Nilsson, Karin

    2016-01-01

    Gliomas are the most common form of malignant primary brain tumors in humans and second most common in dogs, occurring with similar frequencies in both species. Dogs are valuable spontaneous models of human complex diseases including cancers and may provide insight into disease susceptibility and oncogenesis. Several brachycephalic breeds such as Boxer, Bulldog and Boston Terrier have an elevated risk of developing glioma, but others, including Pug and Pekingese, are not at higher risk. To identify glioma-associated genetic susceptibility factors, an across-breed genome-wide association study (GWAS) was performed on 39 dog glioma cases and 141 controls from 25 dog breeds, identifying a genome-wide significant locus on canine chromosome (CFA) 26 (p = 2.8 x 10−8). Targeted re-sequencing of the 3.4 Mb candidate region was performed, followed by genotyping of the 56 SNVs that best fit the association pattern between the re-sequenced cases and controls. We identified three candidate genes that were highly associated with glioma susceptibility: CAMKK2, P2RX7 and DENR. CAMKK2 showed reduced expression in both canine and human brain tumors, and a non-synonymous variant in P2RX7, previously demonstrated to have a 50% decrease in receptor function, was also associated with disease. Thus, one or more of these genes appear to affect glioma susceptibility. PMID:27171399

  2. Utilizing the Dog Genome in the Search for Novel Candidate Genes Involved in Glioma Development-Genome Wide Association Mapping followed by Targeted Massive Parallel Sequencing Identifies a Strongly Associated Locus.

    PubMed

    Truvé, Katarina; Dickinson, Peter; Xiong, Anqi; York, Daniel; Jayashankar, Kartika; Pielberg, Gerli; Koltookian, Michele; Murén, Eva; Fuxelius, Hans-Henrik; Weishaupt, Holger; Swartling, Fredrik J; Andersson, Göran; Hedhammar, Åke; Bongcam-Rudloff, Erik; Forsberg-Nilsson, Karin; Bannasch, Danika; Lindblad-Toh, Kerstin

    2016-05-01

    Gliomas are the most common form of malignant primary brain tumors in humans and second most common in dogs, occurring with similar frequencies in both species. Dogs are valuable spontaneous models of human complex diseases including cancers and may provide insight into disease susceptibility and oncogenesis. Several brachycephalic breeds such as Boxer, Bulldog and Boston Terrier have an elevated risk of developing glioma, but others, including Pug and Pekingese, are not at higher risk. To identify glioma-associated genetic susceptibility factors, an across-breed genome-wide association study (GWAS) was performed on 39 dog glioma cases and 141 controls from 25 dog breeds, identifying a genome-wide significant locus on canine chromosome (CFA) 26 (p = 2.8 x 10-8). Targeted re-sequencing of the 3.4 Mb candidate region was performed, followed by genotyping of the 56 SNVs that best fit the association pattern between the re-sequenced cases and controls. We identified three candidate genes that were highly associated with glioma susceptibility: CAMKK2, P2RX7 and DENR. CAMKK2 showed reduced expression in both canine and human brain tumors, and a non-synonymous variant in P2RX7, previously demonstrated to have a 50% decrease in receptor function, was also associated with disease. Thus, one or more of these genes appear to affect glioma susceptibility.

  3. Improved Heritability Estimation from Genome-wide SNPs

    PubMed Central

    Speed, Doug; Hemani, Gibran; Johnson, Michael R.; Balding, David J.

    2012-01-01

    Estimation of narrow-sense heritability, h2, from genome-wide SNPs genotyped in unrelated individuals has recently attracted interest and offers several advantages over traditional pedigree-based methods. With the use of this approach, it has been estimated that over half the heritability of human height can be attributed to the ∼300,000 SNPs on a genome-wide genotyping array. In comparison, only 5%–10% can be explained by SNPs reaching genome-wide significance. We investigated via simulation the validity of several key assumptions underpinning the mixed-model analysis used in SNP-based h2 estimation. Although we found that the method is reasonably robust to violations of four key assumptions, it can be highly sensitive to uneven linkage disequilibrium (LD) between SNPs: contributions to h2 are overestimated from causal variants in regions of high LD and are underestimated in regions of low LD. The overall direction of the bias can be up or down depending on the genetic architecture of the trait, but it can be substantial in realistic scenarios. We propose a modified kinship matrix in which SNPs are weighted according to local LD. We show that this correction greatly reduces the bias and increases the precision of h2 estimates. We demonstrate the impact of our method on the first seven diseases studied by the Wellcome Trust Case Control Consortium. Our LD adjustment revises downward the h2 estimate for immune-related diseases, as expected because of high LD in the major-histocompatibility region, but increases it for some nonimmune diseases. To calculate our revised kinship matrix, we developed LDAK, software for computing LD-adjusted kinships. PMID:23217325

  4. Genome-wide scans for footprints of natural selection

    PubMed Central

    Oleksyk, Taras K.; Smith, Michael W.; O'Brien, Stephen J.

    2010-01-01

    Detecting recent selected ‘genomic footprints’ applies directly to the discovery of disease genes and in the imputation of the formative events that molded modern population genetic structure. The imprints of historic selection/adaptation episodes left in human and animal genomes allow one to interpret modern and ancestral gene origins and modifications. Current approaches to reveal selected regions applied in genome-wide selection scans (GWSSs) fall into eight principal categories: (I) phylogenetic footprinting, (II) detecting increased rates of functional mutations, (III) evaluating divergence versus polymorphism, (IV) detecting extended segments of linkage disequilibrium, (V) evaluating local reduction in genetic variation, (VI) detecting changes in the shape of the frequency distribution (spectrum) of genetic variation, (VII) assessing differentiating between populations (FST), and (VIII) detecting excess or decrease in admixture contribution from one population. Here, we review and compare these approaches using available human genome-wide datasets to provide independent verification (or not) of regions found by different methods and using different populations. The lessons learned from GWSSs will be applied to identify genome signatures of historic selective pressures on genes and gene regions in other species with emerging genome sequences. This would offer considerable potential for genome annotation in functional, developmental and evolutionary contexts. PMID:20008396

  5. Genome-wide discovery of loci influencing chemotherapy cytotoxicity.

    PubMed

    Watters, James W; Kraja, Aldi; Meucci, Melissa A; Province, Michael A; McLeod, Howard L

    2004-08-10

    Little is known about the heritability of chemotherapy activity or the identity of genes that may enable the individualization of cancer chemotherapy. Although numerous genes are likely to influence chemotherapy response, current candidate gene-based pharmacogenetics approaches require a priori knowledge and the selection of a small number of candidate genes for hypothesis testing. In this study, an ex vivo familial genetics strategy using lymphoblastoid cells derived from Centre d'Etude du Polymorphisme Humain reference pedigrees was used to discover genetic determinants of chemotherapy cytotoxicity. Cytotoxicity to the mechanistically distinct chemotherapy agents 5-fluorouracil and docetaxel were shown to be heritable traits, with heritability values ranging from 0.26 to 0.65 for 5-fluorouracil and 0.21 to 0.70 for docetaxel, varying with dose. Genome-wide linkage analysis was also used to map a quantitative trait locus influencing the cellular effects of 5-fluorouracil to chromosome 9q13-q22 [logarithm of odds (LOD) = 3.44], and two quantitative trait loci influencing the cellular effects of docetaxel to chromosomes 5q11-21 (LOD = 2.21) and 9q13-q22 (LOD = 2.73). Finally, 5-fluorouracil and docetaxel were shown to cause apoptotic cell death involving caspase-3 cleavage in Centre d'Etude du Polymorphisme Humain lymphoblastoid cells. This study identifies genomic regions likely to harbor genes important for chemotherapy cytotoxicity using genome-wide linkage analysis in human pedigrees and provides a widely applicable strategy for pharmacogenomic discovery without the requirement for a priori candidate gene selection.

  6. A genome-wide association study of attempted suicide

    PubMed Central

    Willour, Virginia L.; Seifuddin, Fayaz; Mahon, Pamela B.; Jancic, Dubravka; Pirooznia, Mehdi; Steele, Jo; Schweizer, Barbara; Goes, Fernando S.; Mondimore, Francis M.; MacKinnon, Dean F.; Perlis, Roy H.; Lee, Phil Hyoun; Huang, Jie; Kelsoe, John R.; Shilling, Paul D.; Rietschel, Marcella; Nöthen, Markus; Cichon, Sven; Gurling, Hugh; Purcell, Shaun; Smoller, Jordan W.; Craddock, Nicholas; DePaulo, J. Raymond; Schulze, Thomas G.; McMahon, Francis J.; Zandi, Peter P.; Potash, James B.

    2011-01-01

    The heritable component to attempted and completed suicide is partly related to psychiatric disorders and also partly independent of them. While attempted suicide linkage regions have been identified on 2p11–12 and 6q25–26, there are likely many more such loci, the discovery of which will require a much higher resolution approach, such as the genome-wide association study (GWAS). With this in mind, we conducted an attempted suicide GWAS that compared the single nucleotide polymorphism (SNP) genotypes of 1,201 bipolar (BP) subjects with a history of suicide attempts to the genotypes of 1,497 BP subjects without a history of suicide attempts. 2,507 SNPs with evidence for association at p<0.001 were identified. These associated SNPs were subsequently tested for association in a large and independent BP sample set. None of these SNPs were significantly associated in the replication sample after correcting for multiple testing, but the combined analysis of the two sample sets produced an association signal on 2p25 (rs300774) at the threshold of genome-wide significance (p= 5.07 × 10−8). The associated SNPs on 2p25 fall in a large linkage disequilibrium block containing the ACP1 gene, a gene whose expression is significantly elevated in BP subjects who have completed suicide. Furthermore, the ACP1 protein is a tyrosine phosphatase that influences Wnt signaling, a pathway regulated by lithium, making ACP1 a functional candidate for involvement in the phenotype. Larger GWAS sample sets will be required to confirm the signal on 2p25 and to identify additional genetic risk factors increasing susceptibility for attempted suicide. PMID:21423239

  7. Profiling genome-wide DNA methylation.

    PubMed

    Yong, Wai-Shin; Hsu, Fei-Man; Chen, Pao-Yang

    2016-01-01

    DNA methylation is an epigenetic modification that plays an important role in regulating gene expression and therefore a broad range of biological processes and diseases. DNA methylation is tissue-specific, dynamic, sequence-context-dependent and trans-generationally heritable, and these complex patterns of methylation highlight the significance of profiling DNA methylation to answer biological questions. In this review, we surveyed major methylation assays, along with comparisons and biological examples, to provide an overview of DNA methylation profiling techniques. The advances in microarray and sequencing technologies make genome-wide profiling possible at a single-nucleotide or even a single-cell resolution. These profiling approaches vary in many aspects, such as DNA input, resolution, genomic region coverage, and bioinformatics analysis, and selecting a feasible method requires knowledge of these methods. We first introduce the biological background of DNA methylation and its pattern in plants, animals and fungi. We present an overview of major experimental approaches to profiling genome-wide DNA methylation and hydroxymethylation and then extend to the single-cell methylome. To evaluate these methods, we outline their strengths and weaknesses and perform comparisons across the different platforms. Due to the increasing need to compute high-throughput epigenomic data, we interrogate the computational pipeline for bisulfite sequencing data and also discuss the concept of identifying differentially methylated regions (DMRs). This review summarizes the experimental and computational concepts for profiling genome-wide DNA methylation, followed by biological examples. Overall, this review provides researchers useful guidance for the selection of a profiling method suited to specific research questions.

  8. Genome-Wide Approaches to Schizophrenia

    PubMed Central

    Duan, Jubao; Sanders, Alan R.; Gejman, Pablo V.

    2010-01-01

    Schizophrenia (SZ) is a common and severe psychiatric disorder with both environmental and genetic risk factors, and a high heritability. After over 20 years of molecular genetics research, new molecular strategies, primarily genome-wide association studies (GWAS), have generated major tangible progress. This new data provides evidence for: 1) A number of chromosomal regions with common polymorphisms showing genome-wide association with SZ (the major histocompatibility complex, MHC, region at 6p22-p21; 18q21.2; and 2q32.1). The associated alleles present small odds ratios (the odds of a risk variant being present in cases versus controls) and suggest causative involvement of gene regulatory mechanisms in SZ. 2) Polygenic inheritance. 3) Involvement of rare (<1%) and large (>100kb) copy number variants (CNVs). 4) A genetic overlap of SZ with autism and with bipolar disorder (BP) challenging the classical clinical classifications. Most new SZ findings (chromosomal regions and genes) have generated new biological leads. These new findings, however, still need to be translated into a better understanding of the underlying biology and into causal mechanisms. Furthermore, a considerable amount of heritability still remains unexplained (missing heritability). Deep resequencing for rare variants and system biology approaches (e.g., integrating DNA sequence and functional data) are expected to further improve our understanding of the genetic architecture of SZ and its underlying biology. PMID:20433910

  9. An Efficient Resampling Method for Assessing Genome-Wide Statistical Significance in Mapping Quantitative Trait Loci

    PubMed Central

    Zou, Fei; Fine, Jason P.; Hu, Jianhua; Lin, D. Y.

    2004-01-01

    Assessing genome-wide statistical significance is an important and difficult problem in multipoint linkage analysis. Due to multiple tests on the same genome, the usual pointwise significance level based on the chi-square approximation is inappropriate. Permutation is widely used to determine genome-wide significance. Theoretical approximations are available for simple experimental crosses. In this article, we propose a resampling procedure to assess the significance of genome-wide QTL mapping for experimental crosses. The proposed method is computationally much less intensive than the permutation procedure (in the order of 102 or higher) and is applicable to complex breeding designs and sophisticated genetic models that cannot be handled by the permutation and theoretical methods. The usefulness of the proposed method is demonstrated through simulation studies and an application to a Drosophila backcross. PMID:15611194

  10. Building the Infrastructure of Resource Sharing: Union Catalogs, Distributed Search, and Cross-Database Linkage.

    ERIC Educational Resources Information Center

    Lynch, Clifford A.

    1997-01-01

    Union catalogs and distributed search systems are two ways users can locate materials in print and electronic formats. This article examines the advantages and limitations of both approaches and argues that they should be considered complementary rather than competitive. Discusses technologies creating linkage between catalogs and databases and…

  11. Genome-Wide Association Study Identifies Candidate Loci Underlying Agronomic Traits in a Middle American Diversity Panel of Common Bean.

    PubMed

    Moghaddam, Samira Mafi; Mamidi, Sujan; Osorno, Juan M; Lee, Rian; Brick, Mark; Kelly, James; Miklas, Phillip; Urrea, Carlos; Song, Qijian; Cregan, Perry; Grimwood, Jane; Schmutz, Jeremy; McClean, Phillip E

    2016-11-01

    Common bean ( L.) breeding programs aim to improve both agronomic and seed characteristics traits. However, the genetic architecture of the many traits that affect common bean production are not completely understood. Genome-wide association studies (GWAS) provide an experimental approach to identify genomic regions where important candidate genes are located. A panel of 280 modern bean genotypes from race Mesoamerica, referred to as the Middle American Diversity Panel (MDP), were grown in four US locations, and a GWAS using >150,000 single-nucleotide polymorphisms (SNPs) (minor allele frequency [MAF] ≥ 5%) was conducted for six agronomic traits. The degree of inter- and intrachromosomal linkage disequilibrium (LD) was estimated after accounting for population structure and relatedness. The LD varied between chromosomes for the entire MDP and among race Mesoamerica and Durango-Jalisco genotypes within the panel. The LD patterns reflected the breeding history of common bean. Genome-wide association studies led to the discovery of new and known genomic regions affecting the agronomic traits at the entire population, race, and location levels. We observed strong colocalized signals in a narrow genomic interval for three interrelated traits: growth habit, lodging, and canopy height. Overall, this study detected ∼30 candidate genes based on a priori and candidate gene search strategies centered on the 100-kb region surrounding a significant SNP. These results provide a framework from which further research can begin to understand the actual genes controlling important agronomic production traits in common bean. Copyright © 2016 Crop Science Society of America.

  12. Sample Reproducibility of Genetic Association Using Different Multimarker TDTs in Genome-Wide Association Studies: Characterization and a New Approach

    PubMed Central

    Abad-Grau, Mara M.; Medina-Medina, Nuria; Montes-Soldado, Rosana; Matesanz, Fuencisla; Bafna, Vineet

    2012-01-01

    Multimarker Transmission/Disequilibrium Tests (TDTs) are very robust association tests to population admixture and structure which may be used to identify susceptibility loci in genome-wide association studies. Multimarker TDTs using several markers may increase power by capturing high-degree associations. However, there is also a risk of spurious associations and power reduction due to the increase in degrees of freedom. In this study we show that associations found by tests built on simple null hypotheses are highly reproducible in a second independent data set regardless the number of markers. As a test exhibiting this feature to its maximum, we introduce the multimarker -Groups TDT (), a test which under the hypothesis of no linkage, asymptotically follows a distribution with degree of freedom regardless the number of markers. The statistic requires the division of parental haplotypes into two groups: disease susceptibility and disease protective haplotype groups. We assessed the test behavior by performing an extensive simulation study as well as a real-data study using several data sets of two complex diseases. We show that test is highly efficient and it achieves the highest power among all the tests used, even when the null hypothesis is tested in a second independent data set. Therefore, turns out to be a very promising multimarker TDT to perform genome-wide searches for disease susceptibility loci that may be used as a preprocessing step in the construction of more accurate genetic models to predict individual susceptibility to complex diseases. PMID:22363405

  13. Genome-wide determination of drug localization

    PubMed Central

    Anders, Lars; Guenther, Matthew G.; Qi, Jun; Fan, Zi Peng; Marineau, Jason J.; Rahl, Peter B.; Lovén, Jakob; Sigova, Alla A.; Smith, William B.; Lee, Tong Ihn; Bradner, James E.; Young, Richard A.

    2014-01-01

    A vast number of small-molecule ligands, including therapeutic drugs under development and in clinical use, elicit their effects by binding specific proteins associated with the genome. An ability to map the direct interactions of a chemical entity with chromatin genome-wide could provide new and important insights into chemical perturbation of cellular function. Here we describe a method that couples ligand-affinity capture and massively parallel DNA sequencing (Chem-seq) to identify the sites bound by small chemical molecules throughout the human genome. We show how Chem-seq can be combined with ChIP-seq to gain unique insights into the interaction of drugs with their target proteins throughout the genome of tumor cells. These methods provide a powerful approach to enhance understanding of therapeutic action and characterize the specificity of chemical entities that interact with DNA or genome-associated proteins. PMID:24336317

  14. Genome-Wide Association Studies of Cancer

    PubMed Central

    Stadler, Zsofia K.; Thom, Peter; Robson, Mark E.; Weitzel, Jeffrey N.; Kauff, Noah D.; Hurley, Karen E.; Devlin, Vincent; Gold, Bert; Klein, Robert J.; Offit, Kenneth

    2010-01-01

    Knowledge of the inherited risk for cancer is an important component of preventive oncology. In addition to well-established syndromes of cancer predisposition, much remains to be discovered about the genetic variation underlying susceptibility to common malignancies. Increased knowledge about the human genome and advances in genotyping technology have made possible genome-wide association studies (GWAS) of human diseases. These studies have identified many important regions of genetic variation associated with an increased risk for human traits and diseases including cancer. Understanding the principles, major findings, and limitations of GWAS is becoming increasingly important for oncologists as dissemination of genomic risk tests directly to consumers is already occurring through commercial companies. GWAS have contributed to our understanding of the genetic basis of cancer and will shed light on biologic pathways and possible new strategies for targeted prevention. To date, however, the clinical utility of GWAS-derived risk markers remains limited. PMID:20585100

  15. Genome-wide association and genomic selection in animal breeding.

    PubMed

    Hayes, Ben; Goddard, Mike

    2010-11-01

    Results from genome-wide association studies in livestock, and humans, has lead to the conclusion that the effect of individual quantitative trait loci (QTL) on complex traits, such as yield, are likely to be small; therefore, a large number of QTL are necessary to explain genetic variation in these traits. Given this genetic architecture, gains from marker-assisted selection (MAS) programs using only a small number of DNA markers to trace a limited number of QTL is likely to be small. This has lead to the development of alternative technology for using the available dense single nucleotide polymorphism (SNP) information, called genomic selection. Genomic selection uses a genome-wide panel of dense markers so that all QTL are likely to be in linkage disequilibrium with at least one SNP. The genomic breeding values are predicted to be the sum of the effect of these SNPs across the entire genome. In dairy cattle breeding, the accuracy of genomic estimated breeding values (GEBV) that can be achieved and the fact that these are available early in life have lead to rapid adoption of the technology. Here, we discuss the design of experiments necessary to achieve accurate prediction of GEBV in future generations in terms of the number of markers necessary and the size of the reference population where marker effects are estimated. We also present a simple method for implementing genomic selection using a genomic relationship matrix. Future challenges discussed include using whole genome sequence data to improve the accuracy of genomic selection and management of inbreeding through genomic relationships.

  16. A genome-wide scan for type 1 diabetes susceptibility genes in nuclear families with multiple affected siblings in Finland.

    PubMed

    Qiao, Qing; Osterholm, Anne-May; He, Bing; Pitkäniemi, Janne; Cordell, Heather J; Sarti, Cinzia; Kinnunen, Leena; Tuomilehto-Wolf, Eva; Tryggvason, Karl; Tuomilehto, Jaakko

    2007-12-19

    A genome-wide search for genes that predispose to type 1 diabetes using linkage analysis was performed using 900 microsatellite markers in 70 nuclear families with affected siblings from Finland, a population expected to be more genetically homogeneous than others, and having the highest incidence of type 1 diabetes in the world and, yet, the highest proportion in Europe of cases (10%) carrying neither of the highest risk HLA haplotypes that include DR3 or DR4 alleles. In addition to the evidence of linkage to the HLA region on 6p21 (nominal p = 4.0 x 10-6), significant evidence of linkage in other chromosome regions was not detected with a single-locus analysis. The two-locus analysis conditional on the HLA gave a maximum lod score (MLS) of 3.1 (nominal p = 2 x 10-4) on chromosome 9p13 under an additive model; MLS of 2.1 (nominal p = 6.1 x 10-3) on chromosome 17p12 and MLS of 2.5 (nominal p = 2.9 x 10-3) on chromosome 18p11 under a general model. Our genome scan data confirmed the primary contribution of the HLA genes also in the high-risk Finnish population, and suggest that non-HLA genes also contribute to the familial clustering of type 1 diabetes in Finland.

  17. [Genome-wide associations for cigarette smoking behavior].

    PubMed

    Strauss, Ewa

    2013-01-01

    Diseases related to tobacco smoking are the second leading cause of death in the world. Despite increasing evidence of genetic determination, the susceptibility genes and loci underlying various aspects of smoking behavior are largely unknown. Genome-wide association studies (GWASs) provided a new conceptual framework in the search for variants underlying common traits/disorders. A massive scan of the genome and a "hypothesis-free" approach enable discovery of new aspects of genetics of complex traits. In this paper the results of GWASs and GWAS meta-analyzes of cigarette smoking behavior and nicotine dependence are reviewed with the particular attention to smoking cessation success and the replacement therapy. The results of these studies are discussed in the context of the results of the candidate gene association studies. Studies on the role of the genomic regions, identified in GWASs, in the development of smoking-related diseases are also discussed.

  18. Efficient strategies for genomic searching using the affected-pedigree-member method of linkage analysis

    SciTech Connect

    Brown, D.L.; Gorin, M.B.; Weeks, D.E. )

    1994-03-01

    The affected-pedigree-member (APM) method of linkage analysis is a nonparametric statistic that tests for nonrandom cosegregation of a disease and marker loci. The APM statistic is based on the observation that if a marker locus is near a disease-susceptibility locus, then affected individuals within a family should be more similar at the marker locus than is expected by chance. The APM statistic measures marker similarity in terms of identity by state (IBS) of marker alleles; that is, two alleles are IBS if they are the same, regardless of their ancestral origin. Since the APM statistic measures increased marker similarity, it makes no assumptions concerning how the disease is inherited; this can be an advantage when dealing with complex diseases for which the mode of inheritance is difficult to determine. The authors investigate here the power of the APM statistic to detect linkage in the context of a genomewide search. In such a search, the APM statistic is evaluated at a grid of markers. Then regions with high APM statistics are investigated more thoroughly by typing more markers in the region. Using simulated data, they investigate various search strategies and recommended an optimal search strategy that maximizes the power to detect linkage while minimizing the false-positive rate and number of markers. They determine an optimal series of three increasing cut-points and an independent criterion for significance. 14 refs., 7 figs., 4 tabs.

  19. Genome-wide association filtering using a highly locus-specific transmission/disequilibrium test

    PubMed Central

    Medina-Medina, Nuria; Montes-Soldado, Rosana; Moreno-Ortega, José; Matesanz, Fuencisla

    2010-01-01

    Multimarker transmission/disequilibrium tests (TDTs) are powerful association and linkage tests used to perform genome-wide filtering in the search for disease susceptibility loci. In contrast to case/control studies, they have a low rate of false positives for population stratification and admixture. However, the length of a region found in association with a disease is usually very large because of linkage disequilibrium (LD). Here, we define a multimarker proportional TDT (mTDTP) designed to improve locus specificity in complex diseases that has good power compared to the most powerful multimarker TDTs. The test is a simple generalization of a multimarker TDT in which haplotype frequencies are used to weight the effect that each haplotype has on the whole measure. Two concepts underlie the features of the metric: the ‘common disease, common variant’ hypothesis and the decrease in LD with chromosomal distance. Because of this decrease, the frequency of haplotypes in strong LD with common disease variants decreases with increasing distance from the disease susceptibility locus. Thus, our haplotype proportional test has higher locus specificity than common multimarker TDTs that assume a uniform distribution of haplotype probabilities. Because of the common variant hypothesis, risk haplotypes at a given locus are relatively frequent and a metric that weights partial results for each haplotype by its frequency will be as powerful as the most powerful multimarker TDTs. Simulations and real data sets demonstrate that the test has good power compared with the best tests but has remarkably higher locus specificity, so that the association rate decreases at a higher rate with distance from a disease susceptibility or disease protective locus. PMID:20603721

  20. Genome-wide association filtering using a highly locus-specific transmission/disequilibrium test.

    PubMed

    Abad-Grau, María M; Medina-Medina, Nuria; Montes-Soldado, Rosana; Moreno-Ortega, José; Matesanz, Fuencisla

    2010-09-01

    Multimarker transmission/disequilibrium tests (TDTs) are powerful association and linkage tests used to perform genome-wide filtering in the search for disease susceptibility loci. In contrast to case/control studies, they have a low rate of false positives for population stratification and admixture. However, the length of a region found in association with a disease is usually very large because of linkage disequilibrium (LD). Here, we define a multimarker proportional TDT (mTDT ( P )) designed to improve locus specificity in complex diseases that has good power compared to the most powerful multimarker TDTs. The test is a simple generalization of a multimarker TDT in which haplotype frequencies are used to weight the effect that each haplotype has on the whole measure. Two concepts underlie the features of the metric: the 'common disease, common variant' hypothesis and the decrease in LD with chromosomal distance. Because of this decrease, the frequency of haplotypes in strong LD with common disease variants decreases with increasing distance from the disease susceptibility locus. Thus, our haplotype proportional test has higher locus specificity than common multimarker TDTs that assume a uniform distribution of haplotype probabilities. Because of the common variant hypothesis, risk haplotypes at a given locus are relatively frequent and a metric that weights partial results for each haplotype by its frequency will be as powerful as the most powerful multimarker TDTs. Simulations and real data sets demonstrate that the test has good power compared with the best tests but has remarkably higher locus specificity, so that the association rate decreases at a higher rate with distance from a disease susceptibility or disease protective locus.

  1. A Genome-Wide Perspective on Metabolism.

    PubMed

    Rauch, Alexander; Mandrup, Susanne

    2016-01-01

    Mammals have at least 210 histologically diverse cell types (Alberts, Molecular biology of the cell. Garland Science, New York, 2008) and the number would be even higher if functional differences are taken into account. The genome in each of these cell types is differentially programmed to express the specific set of genes needed to fulfill the phenotypical requirements of the cell. Furthermore, in each of these cell types, the gene program can be differentially modulated by exposure to external signals such as hormones or nutrients. The basis for the distinct gene programs relies on cell type-selective activation of transcriptional enhancers, which in turn are particularly sensitive to modulation. Until recently we had only fragmented insight into the regulation of a few of these enhancers; however, the recent advances in high-throughput sequencing technologies have enabled the development of a large number of technologies that can be used to obtain genome-wide insight into how genomes are reprogrammed during development and in response to specific external signals. By applying such technologies, we have begun to reveal the cross-talk between metabolism and the genome, i.e., how genomes are reprogrammed in response to metabolites, and how the regulation of metabolic networks is coordinated at the genomic level.

  2. Genome-wide analysis correlates Ayurveda Prakriti

    PubMed Central

    Govindaraj, Periyasamy; Nizamuddin, Sheikh; Sharath, Anugula; Jyothi, Vuskamalla; Rotti, Harish; Raval, Ritu; Nayak, Jayakrishna; Bhat, Balakrishna K.; Prasanna, B. V.; Shintre, Pooja; Sule, Mayura; Joshi, Kalpana S.; Dedge, Amrish P.; Bharadwaj, Ramachandra; Gangadharan, G. G.; Nair, Sreekumaran; Gopinath, Puthiya M.; Patwardhan, Bhushan; Kondaiah, Paturu; Satyamoorthy, Kapaettu; Valiathan, Marthanda Varma Sankaran; Thangaraj, Kumarasamy

    2015-01-01

    The practice of Ayurveda, the traditional medicine of India, is based on the concept of three major constitutional types (Vata, Pitta and Kapha) defined as “Prakriti”. To the best of our knowledge, no study has convincingly correlated genomic variations with the classification of Prakriti. In the present study, we performed genome-wide SNP (single nucleotide polymorphism) analysis (Affymetrix, 6.0) of 262 well-classified male individuals (after screening 3416 subjects) belonging to three Prakritis. We found 52 SNPs (p ≤ 1 × 10−5) were significantly different between Prakritis, without any confounding effect of stratification, after 106 permutations. Principal component analysis (PCA) of these SNPs classified 262 individuals into their respective groups (Vata, Pitta and Kapha) irrespective of their ancestry, which represent its power in categorization. We further validated our finding with 297 Indian population samples with known ancestry. Subsequently, we found that PGM1 correlates with phenotype of Pitta as described in the ancient text of Caraka Samhita, suggesting that the phenotypic classification of India’s traditional medicine has a genetic basis; and its Prakriti-based practice in vogue for many centuries resonates with personalized medicine. PMID:26511157

  3. Reconstructing Roma History from Genome-Wide Data

    PubMed Central

    Moorjani, Priya; Patterson, Nick; Loh, Po-Ru; Lipson, Mark; Kisfali, Péter; Melegh, Bela I.; Bonin, Michael; Kádaši, Ľudevít; Rieß, Olaf; Berger, Bonnie; Reich, David; Melegh, Béla

    2013-01-01

    The Roma people, living throughout Europe and West Asia, are a diverse population linked by the Romani language and culture. Previous linguistic and genetic studies have suggested that the Roma migrated into Europe from South Asia about 1,000–1,500 years ago. Genetic inferences about Roma history have mostly focused on the Y chromosome and mitochondrial DNA. To explore what additional information can be learned from genome-wide data, we analyzed data from six Roma groups that we genotyped at hundreds of thousands of single nucleotide polymorphisms (SNPs). We estimate that the Roma harbor about 80% West Eurasian ancestry–derived from a combination of European and South Asian sources–and that the date of admixture of South Asian and European ancestry was about 850 years before present. We provide evidence for Eastern Europe being a major source of European ancestry, and North-west India being a major source of the South Asian ancestry in the Roma. By computing allele sharing as a measure of linkage disequilibrium, we estimate that the migration of Roma out of the Indian subcontinent was accompanied by a severe founder event, which appears to have been followed by a major demographic expansion after the arrival in Europe. PMID:23516520

  4. Fine mapping by composite genome-wide association analysis.

    PubMed

    Casellas, Joaquim; Cañas-Álvarez, Jhon Jacobo; Fina, Marta; Piedrafita, Jesús; Cecchinato, Alessio

    2017-06-06

    Genome-wide association (GWA) studies play a key role in current genetics research, unravelling genomic regions linked to phenotypic traits of interest in multiple species. Nevertheless, the extent of linkage disequilibrium (LD) may provide confounding results when significant genetic markers span along several contiguous cM. In this study, we have adapted the composite interval mapping approach to the GWA framework (composite GWA), in order to evaluate the impact of including competing (possibly linked) genetic markers when testing for the additive allelic effect inherent to a given genetic marker. We tested model performance on simulated data sets under different scenarios (i.e., qualitative trait loci effects, LD between genetic markers and width of the genomic region involved in the analysis). Our results showed that the genomic region had a small impact on the number of competing single nucleotide polymorphisms (SNPs) as well as on the precision of the composite GWA analysis. A similar conclusion was derived from the preferable range of LD between the tested SNP and competing SNPs, although moderate-to-high LD seemed to attenuate the loss of statistical power. The composite GWA improved specificity and reduced the number of significant genetic markers. The composite GWA model contributes a novel point of view for GWA analyses where testing circumscribed to the genomic region flanking each SNP (delimited by the nearest competing SNPs) and conditioning on linked markers increases the precision to locate causal mutations, but possibly at the expense of power.

  5. Weighted SNP set analysis in genome-wide association study.

    PubMed

    Dai, Hui; Zhao, Yang; Qian, Cheng; Cai, Min; Zhang, Ruyang; Chu, Minjie; Dai, Juncheng; Hu, Zhibin; Shen, Hongbing; Chen, Feng

    2013-01-01

    Genome-wide association studies (GWAS) are popular for identifying genetic variants which are associated with disease risk. Many approaches have been proposed to test multiple single nucleotide polymorphisms (SNPs) in a region simultaneously which considering disadvantages of methods in single locus association analysis. Kernel machine based SNP set analysis is more powerful than single locus analysis, which borrows information from SNPs correlated with causal or tag SNPs. Four types of kernel machine functions and principal component based approach (PCA) were also compared. However, given the loss of power caused by low minor allele frequencies (MAF), we conducted an extension work on PCA and used a new method called weighted PCA (wPCA). Comparative analysis was performed for weighted principal component analysis (wPCA), logistic kernel machine based test (LKM) and principal component analysis (PCA) based on SNP set in the case of different minor allele frequencies (MAF) and linkage disequilibrium (LD) structures. We also applied the three methods to analyze two SNP sets extracted from a real GWAS dataset of non-small cell lung cancer in Han Chinese population. Simulation results show that when the MAF of the causal SNP is low, weighted principal component and weighted IBS are more powerful than PCA and other kernel machine functions at different LD structures and different numbers of causal SNPs. Application of the three methods to a real GWAS dataset indicates that wPCA and wIBS have better performance than the linear kernel, IBS kernel and PCA.

  6. Genome-wide analysis links NFATC2 with asparaginase hypersensitivity

    PubMed Central

    Fernandez, Christian A.; Smith, Colton; Yang, Wenjian; Mullighan, Charles G.; Qu, Chunxu; Larsen, Eric; Bowman, W. Paul; Liu, Chengcheng; Ramsey, Laura B.; Chang, Tamara; Karol, Seth E.; Loh, Mignon L.; Raetz, Elizabeth A.; Winick, Naomi J.; Hunger, Stephen P.; Carroll, William L.; Jeha, Sima; Pui, Ching-Hon; Evans, William E.; Devidas, Meenakshi

    2015-01-01

    Asparaginase is used to treat acute lymphoblastic leukemia (ALL); however, hypersensitivity reactions can lead to suboptimal asparaginase exposure. Our objective was to use a genome-wide approach to identify loci associated with asparaginase hypersensitivity in children with ALL enrolled on St. Jude Children’s Research Hospital (SJCRH) protocols Total XIIIA (n = 154), Total XV (n = 498), and Total XVI (n = 271), or Children’s Oncology Group protocols POG 9906 (n = 222) and AALL0232 (n = 2163). Germline DNA was genotyped using the Affymetrix 500K, Affymetrix 6.0, or the Illumina Exome BeadChip array. In multivariate logistic regression, the intronic rs6021191 variant in nuclear factor of activated T cells 2 (NFATC2) had the strongest association with hypersensitivity (P = 4.1 × 10−8; odds ratio [OR] = 3.11). RNA-seq data available from 65 SJCRH ALL tumor samples and 52 Yoruba HapMap samples showed that samples carrying the rs6021191 variant had higher NFATC2 expression compared with noncarriers (P = 1.1 × 10−3 and 0.03, respectively). The top ranked nonsynonymous polymorphism was rs17885382 in HLA-DRB1 (P = 3.2 × 10−6; OR = 1.63), which is in near complete linkage disequilibrium with the HLA-DRB1*07:01 allele we previously observed in a candidate gene study. The strongest risk factors for asparaginase allergy are variants within genes regulating the immune response. PMID:25987655

  7. Genome-wide association study and premature ovarian failure.

    PubMed

    Christin-Maitre, S; Tachdjian, G

    2010-05-01

    Premature ovarian failure (POF) is defined as an amenorrhea for more than 4months, associated with elevated gonadotropins, usually higher than 20mIU/ml, occurring in a woman before the age of 40. Some candidate genes have been identified in the past 15years, such as FOXL2, FSHR, BMP15, GDF9, Xfra premutation. However, POF etiology remains unknown in more than 90% of cases. The first strategy to identify candidate gene, apart from studying genes involved in ovarian failure in animal models, relies on the study of X chromosome deletions and X;autosome translocations in patients. The second strategy is based on linkage analysis, the third one on Comparative Genomic Hybridization (CGH) array. The latest strategy relies on Genome-Wide Association Studies (GWAS). This technique consists in screening single nucleotide polymorphisms (SNPs) in patients and controls. So far, three studies have been performed and have identified different loci potentially linked to POF, such as PTHB1 and ADAMTS19. However, replications in independent cohorts need to be performed. GWAS studies on large cohorts of women with POF should find new candidate genes in the near future. Copyright 2010. Published by Elsevier Masson SAS.

  8. Genome wide selection in Citrus breeding.

    PubMed

    Gois, I B; Borém, A; Cristofani-Yaly, M; de Resende, M D V; Azevedo, C F; Bastianel, M; Novelli, V M; Machado, M A

    2016-10-17

    Genome wide selection (GWS) is essential for the genetic improvement of perennial species such as Citrus because of its ability to increase gain per unit time and to enable the efficient selection of characteristics with low heritability. This study assessed GWS efficiency in a population of Citrus and compared it with selection based on phenotypic data. A total of 180 individual trees from a cross between Pera sweet orange (Citrus sinensis Osbeck) and Murcott tangor (Citrus sinensis Osbeck x Citrus reticulata Blanco) were evaluated for 10 characteristics related to fruit quality. The hybrids were genotyped using 5287 DArT_seq(TM) (diversity arrays technology) molecular markers and their effects on phenotypes were predicted using the random regression - best linear unbiased predictor (rr-BLUP) method. The predictive ability, prediction bias, and accuracy of GWS were estimated to verify its effectiveness for phenotype prediction. The proportion of genetic variance explained by the markers was also computed. The heritability of the traits, as determined by markers, was 16-28%. The predictive ability of these markers ranged from 0.53 to 0.64, and the regression coefficients between predicted and observed phenotypes were close to unity. Over 35% of the genetic variance was accounted for by the markers. Accuracy estimates with GWS were lower than those obtained by phenotypic analysis; however, GWS was superior in terms of genetic gain per unit time. Thus, GWS may be useful for Citrus breeding as it can predict phenotypes early and accurately, and reduce the length of the selection cycle. This study demonstrates the feasibility of genomic selection in Citrus.

  9. Genome-wide positioning of bivalent mononucleosomes.

    PubMed

    Sen, Subhojit; Block, Kirsten F; Pasini, Alice; Baylin, Stephen B; Easwaran, Hariharan

    2016-09-15

    Bivalent chromatin refers to overlapping regions containing activating histone H3 Lys4 trimethylation (H3K4me3) and inactivating H3K27me3 marks. Existence of such bivalent marks on the same nucleosome has only recently been suggested. Previous genome-wide efforts to characterize bivalent chromatin have focused primarily on individual marks to define overlapping zones of bivalency rather than mapping positions of truly bivalent mononucleosomes. Here, we developed an efficacious sequential ChIP technique for examining global positioning of individual bivalent nucleosomes. Using next generation sequencing approaches we show that although individual H3K4me3 and H3K27me3 marks overlap in broad zones, bivalent nucleosomes are focally enriched in the vicinity of the transcription start site (TSS). These seem to occupy the H2A.Z nucleosome positions previously described as salt-labile nucleosomes, and are correlated with low gene expression. Although the enrichment profiles of bivalent nucleosomes show a clear dependency on CpG island content, they demonstrate a stark anti-correlation with methylation status. We show that regional overlap of H3K4me3 and H3K27me3 chromatin tend to be upstream to the TSS, while bivalent nucleosomes with both marks are mainly promoter proximal near the TSS of CpG island-containing genes with poised/low expression. We discuss the implications of the focal enrichment of bivalent nucleosomes around the TSS on the poised chromatin state of promoters in stem cells.

  10. Genome Wide Methylome Alterations in Lung Cancer.

    PubMed

    Mullapudi, Nandita; Ye, Bin; Suzuki, Masako; Fazzari, Melissa; Han, Weiguo; Shi, Miao K; Marquardt, Gaby; Lin, Juan; Wang, Tao; Keller, Steven; Zhu, Changcheng; Locker, Joseph D; Spivack, Simon D

    2015-01-01

    Aberrant cytosine 5-methylation underlies many deregulated elements of cancer. Among paired non-small cell lung cancers (NSCLC), we sought to profile DNA 5-methyl-cytosine features which may underlie genome-wide deregulation. In one of the more dense interrogations of the methylome, we sampled 1.2 million CpG sites from twenty-four NSCLC tumor (T)-non-tumor (NT) pairs using a methylation-sensitive restriction enzyme- based HELP-microarray assay. We found 225,350 differentially methylated (DM) sites in adenocarcinomas versus adjacent non-tumor tissue that vary in frequency across genomic compartment, particularly notable in gene bodies (GB; p<2.2E-16). Further, when DM was coupled to differential transcriptome (DE) in the same samples, 37,056 differential loci in adenocarcinoma emerged. Approximately 90% of the DM-DE relationships were non-canonical; for example, promoter DM associated with DE in the same direction. Of the canonical changes noted, promoter (PR) DM loci with reciprocal changes in expression in adenocarcinomas included HBEGF, AGER, PTPRM, DPT, CST1, MELK; DM GB loci with concordant changes in expression included FOXM1, FERMT1, SLC7A5, and FAP genes. IPA analyses showed adenocarcinoma-specific promoter DMxDE overlay identified familiar lung cancer nodes [tP53, Akt] as well as less familiar nodes [HBEGF, NQO1, GRK5, VWF, HPGD, CDH5, CTNNAL1, PTPN13, DACH1, SMAD6, LAMA3, AR]. The unique findings from this study include the discovery of numerous candidate The unique findings from this study include the discovery of numerous candidate methylation sites in both PR and GB regions not previously identified in NSCLC, and many non-canonical relationships to gene expression. These DNA methylation features could potentially be developed as risk or diagnostic biomarkers, or as candidate targets for newer methylation locus-targeted preventive or therapeutic agents.

  11. Genome Wide Methylome Alterations in Lung Cancer

    PubMed Central

    Suzuki, Masako; Fazzari, Melissa; Han, Weiguo; Shi, Miao K.; Marquardt, Gaby; Lin, Juan; Wang, Tao; Keller, Steven; Zhu, Changcheng; Locker, Joseph D.; Spivack, Simon D.

    2015-01-01

    Aberrant cytosine 5-methylation underlies many deregulated elements of cancer. Among paired non-small cell lung cancers (NSCLC), we sought to profile DNA 5-methyl-cytosine features which may underlie genome-wide deregulation. In one of the more dense interrogations of the methylome, we sampled 1.2 million CpG sites from twenty-four NSCLC tumor (T)–non-tumor (NT) pairs using a methylation-sensitive restriction enzyme- based HELP-microarray assay. We found 225,350 differentially methylated (DM) sites in adenocarcinomas versus adjacent non-tumor tissue that vary in frequency across genomic compartment, particularly notable in gene bodies (GB; p<2.2E-16). Further, when DM was coupled to differential transcriptome (DE) in the same samples, 37,056 differential loci in adenocarcinoma emerged. Approximately 90% of the DM-DE relationships were non-canonical; for example, promoter DM associated with DE in the same direction. Of the canonical changes noted, promoter (PR) DM loci with reciprocal changes in expression in adenocarcinomas included HBEGF, AGER, PTPRM, DPT, CST1, MELK; DM GB loci with concordant changes in expression included FOXM1, FERMT1, SLC7A5, and FAP genes. IPA analyses showed adenocarcinoma-specific promoter DMxDE overlay identified familiar lung cancer nodes [tP53, Akt] as well as less familiar nodes [HBEGF, NQO1, GRK5, VWF, HPGD, CDH5, CTNNAL1, PTPN13, DACH1, SMAD6, LAMA3, AR]. The unique findings from this study include the discovery of numerous candidate The unique findings from this study include the discovery of numerous candidate methylation sites in both PR and GB regions not previously identified in NSCLC, and many non-canonical relationships to gene expression. These DNA methylation features could potentially be developed as risk or diagnostic biomarkers, or as candidate targets for newer methylation locus-targeted preventive or therapeutic agents. PMID:26683690

  12. Genome-wide identification of molecular mimicry candidates in parasites.

    PubMed

    Ludin, Philipp; Nilsson, Daniel; Mäser, Pascal

    2011-03-08

    Among the many strategies employed by parasites for immune evasion and host manipulation, one of the most fascinating is molecular mimicry. With genome sequences available for host and parasite, mimicry of linear amino acid epitopes can be investigated by comparative genomics. Here we developed an in silico pipeline for genome-wide identification of molecular mimicry candidate proteins or epitopes. The predicted proteome of a given parasite was broken down into overlapping fragments, each of which was screened for close hits in the human proteome. Control searches were carried out against unrelated, free-living eukaryotes to eliminate the generally conserved proteins, and with randomized versions of the parasite proteins to get an estimate of statistical significance. This simple but computation-intensive approach yielded interesting candidates from human-pathogenic parasites. From Plasmodium falciparum, it returned a 14 amino acid motif in several of the PfEMP1 variants identical to part of the heparin-binding domain in the immunosuppressive serum protein vitronectin. And in Brugia malayi, fragments were detected that matched to periphilin-1, a protein of cell-cell junctions involved in barrier formation. All the results are publicly available by means of mimicDB, a searchable online database for molecular mimicry candidates from pathogens. To our knowledge, this is the first genome-wide survey for molecular mimicry proteins in parasites. The strategy can be adopted to any pair of host and pathogen, once appropriate negative control organisms are chosen. MimicDB provides a host of new starting points to gain insights into the molecular nature of host-pathogen interactions.

  13. Genome-Wide Identification of Molecular Mimicry Candidates in Parasites

    PubMed Central

    Ludin, Philipp; Nilsson, Daniel; Mäser, Pascal

    2011-01-01

    Among the many strategies employed by parasites for immune evasion and host manipulation, one of the most fascinating is molecular mimicry. With genome sequences available for host and parasite, mimicry of linear amino acid epitopes can be investigated by comparative genomics. Here we developed an in silico pipeline for genome-wide identification of molecular mimicry candidate proteins or epitopes. The predicted proteome of a given parasite was broken down into overlapping fragments, each of which was screened for close hits in the human proteome. Control searches were carried out against unrelated, free-living eukaryotes to eliminate the generally conserved proteins, and with randomized versions of the parasite proteins to get an estimate of statistical significance. This simple but computation-intensive approach yielded interesting candidates from human-pathogenic parasites. From Plasmodium falciparum, it returned a 14 amino acid motif in several of the PfEMP1 variants identical to part of the heparin-binding domain in the immunosuppressive serum protein vitronectin. And in Brugia malayi, fragments were detected that matched to periphilin-1, a protein of cell-cell junctions involved in barrier formation. All the results are publicly available by means of mimicDB, a searchable online database for molecular mimicry candidates from pathogens. To our knowledge, this is the first genome-wide survey for molecular mimicry proteins in parasites. The strategy can be adopted to any pair of host and pathogen, once appropriate negative control organisms are chosen. MimicDB provides a host of new starting points to gain insights into the molecular nature of host-pathogen interactions. PMID:21408160

  14. Genome-wide association study of circulating vitamin D levels.

    PubMed

    Ahn, Jiyoung; Yu, Kai; Stolzenberg-Solomon, Rachael; Simon, K Claire; McCullough, Marjorie L; Gallicchio, Lisa; Jacobs, Eric J; Ascherio, Alberto; Helzlsouer, Kathy; Jacobs, Kevin B; Li, Qizhai; Weinstein, Stephanie J; Purdue, Mark; Virtamo, Jarmo; Horst, Ronald; Wheeler, William; Chanock, Stephen; Hunter, David J; Hayes, Richard B; Kraft, Peter; Albanes, Demetrius

    2010-07-01

    The primary circulating form of vitamin D, 25-hydroxy-vitamin D [25(OH)D], is associated with multiple medical outcomes, including rickets, osteoporosis, multiple sclerosis and cancer. In a genome-wide association study (GWAS) of 4501 persons of European ancestry drawn from five cohorts, we identified single-nucleotide polymorphisms (SNPs) in the gene encoding group-specific component (vitamin D binding) protein, GC, on chromosome 4q12-13 that were associated with 25(OH)D concentrations: rs2282679 (P=2.0x10(-30)), in linkage disequilibrium (LD) with rs7041, a non-synonymous SNP (D432E; P=4.1x10(-22)) and rs1155563 (P=3.8x10(-25)). Suggestive signals for association with 25(OH)D were also observed for SNPs in or near three other genes involved in vitamin D synthesis or activation: rs3829251 on chromosome 11q13.4 in NADSYN1 [encoding nicotinamide adenine dinucleotide (NAD) synthetase; P=8.8x10(-7)], which was in high LD with rs1790349, located in DHCR7, the gene encoding 7-dehydrocholesterol reductase that synthesizes cholesterol from 7-dehydrocholesterol; rs6599638 in the region harboring the open-reading frame 88 (C10orf88) on chromosome 10q26.13 in the vicinity of ACADSB (acyl-Coenzyme A dehydrogenase), involved in cholesterol and vitamin D synthesis (P=3.3x10(-7)); and rs2060793 on chromosome 11p15.2 in CYP2R1 (cytochrome P450, family 2, subfamily R, polypeptide 1, encoding a key C-25 hydroxylase that converts vitamin D3 to an active vitamin D receptor ligand; P=1.4x10(-5)). We genotyped SNPs in these four regions in 2221 additional samples and confirmed strong genome-wide significant associations with 25(OH)D through meta-analysis with the GWAS data for GC (P=1.8x10(-49)), NADSYN1/DHCR7 (P=3.4x10(-9)) and CYP2R1 (P=2.9x10(-17)), but not C10orf88 (P=2.4x10(-5)).

  15. Genome-wide search for ionizing radiation responsive elements in Deinococcus radiodurans reveals regulatory role of the DNA gyrase subunit A 5' UTR in the Radiation and Desiccation Response (RDR).

    PubMed

    Villa, Jordan K; Amador, Paul; Janovsky, Justin; Bhuyan, Arijit; Saldanha, Roland; Lamkin, Thomas J; Contreras, Lydia M

    2017-04-14

    Tight regulation of gene expression is important for Deinococcus radiodurans survival, a model bacterium of extreme stress resistance. Few studies have examined the use of regulatory RNAs as a possible contributing mechanism to ionizing radiation (IR) resistance, despite their proffered efficient and dynamic gene expression regulation under IR stress. This work presents a transcriptome-based approach for identification of stress-responsive regulatory 5' UTR elements in D. radiodurans R1 that can be broadly applied to other bacteria. Using this platform and an in vivo fluorescence screen, we uncovered the presence of a radiation-responsive regulatory motif in the 5' UTR of DNA gyrase subunit A Additional screens under H2O2-induced oxidative stress revealed the specificity of the response of this element to IR stress. Further examination of the sequence revealed a regulatory motif of the Radiation and Desiccation Response (RDR) in the 5' UTR that is necessary for D. radiodurans recovery from high doses of IR. Furthermore, we suggest that it is the preservation of predicted RNA structure, in addition to DNA sequence consensus, of the motif that permits this important regulatory ability.IMPORTANCEDeinococcus radiodurans is an extremely stress resistant bacterium capable of tolerating up to 3,000 times more ionizing radiation than human cells. As an integral part of the stress response mechanism of this organism, we suspect that it maintains stringent control of gene expression. However, understanding of its regulatory pathways remains incomplete to date. Untranslated RNA elements have been demonstrated to play crucial roles in gene regulation throughout bacteria. In this work, we focus on searching for and characterizing responsive RNA elements under radiation stress and propose that multiple levels of gene regulation simultaneously work to enable this organism to efficiently recover from exposure to ionizing radiation. The model we propose serves as a generic template

  16. Genome-wide association study dissects the genetic architecture of oil biosynthesis and accumulation in maize kernel

    USDA-ARS?s Scientific Manuscript database

    A Genome Wide Association Study (GWAS) on a population of 368 maize inbreds with 1.06 million SNPs was performed and identified 74 highly significantly associated genes influencing maize kernel oil content and fatty acid composition. To validate these findings, three biparental linkage mapping popul...

  17. Genome-Wide Association Study of Septoria tritici Blotch Resistance in Ethiopian Durum Wheat Landraces.

    PubMed

    Kidane, Yosef G; Hailemariam, Bogale N; Mengistu, Dejene K; Fadda, Carlo; Pè, Mario Enrico; Dell'Acqua, Matteo

    2017-01-01

    Septoria tritici blotch (STB) is a devastating fungal disease affecting durum and bread wheat cultivation worldwide. The identification, development, and employment of resistant wheat genetic material is the key to overcoming costs and limitations of fungicide treatments. The search for resistance sources in untapped genetic material may speed up the deployment of STB genetic resistance in the field. Ethiopian durum wheat landraces represent a valuable source of such diversity. In this study, 318 Ethiopian durum wheat genotypes, for the most part traditional landraces, were phenotyped for resistance to different aspects of STB infection. Phenology, yield and yield component traits were concurrently measured the collection. Here we describe the distribution of STB resistance traits in modern varieties and in landraces, and the relation existing between STB resistance and other agronomic traits. STB resistance sources were found in landraces as well as in modern varieties tested, suggesting the presence of alleles of breeding relevance. The genetic material was genotyped with more than 16 thousand genome-wide polymorphic markers to describe the linkage disequilibrium and genetic structure existing within the panel of genotypes, and a genome-wide association (GWA) study was run to allow the identification of genomic loci involved in STB resistance. High diversity and low genetic structure in the panel allowed high efficiency GWA. The GWA scan detected five major putative QTL for STB resistance, only partially overlapping those already reported in the wheat literature. We report four putative loci for Septoria resistance with no match in previous literature: two highly significant ones on Chr 3A and 5A, and two suggestive ones on Chr 4B and 5B. Markers underlying these QTL explained as much as 10% of the phenotypic variance for disease resistance. We found three cases in which putative QTL for agronomic traits overlapped marker trait association deriving from STB GWA

  18. A Discovery Genome-Wide Association Study of Entrepreneurship

    ERIC Educational Resources Information Center

    Quaye, Lydia; Nicolaou, Nicos; Shane, Scott; Mangino, Massimo

    2012-01-01

    To identify specific genetic variants influencing the phenotype of entrepreneurship, we conducted a genome-wide association study (GWAS) with 3,933 Caucasian females from the TwinsUK Adult Twin Registry. Following stringent genotype quality control, GWAF (genome-wide association analyses for family data) software was used to assess the association…

  19. Biostatistical aspects of genome-wide association studies.

    PubMed

    Ziegler, Andreas; König, Inke R; Thompson, John R

    2008-02-01

    To search the entire human genome for association is a novel and promising approach to unravelling the genetic basis of complex genetic diseases. In these genome-wide association studies (GWAs), several hundreds of thousands of single nucleotide polymorphisms (SNPs) are analyzed at the same time, posing substantial biostatistical and computational challenges. In this paper, we discuss a number of biostatistical aspects of GWAs in detail. We specifically consider quality control issues and show that signal intensity plots are a sine qua condition non in today's GWAs. Approaches to detect and adjust for population stratification are briefly examined. We discuss different strategies aimed at tackling the problem of multiple testing, including adjustment of p -values, the false positive report probability and the false discovery rate. Another aspect of GWAs requiring special attention is the search for gene-gene and gene-environment interactions. We finally describe multistage approaches to GWAs. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  20. Genome-wide association analyses identify 13 new susceptibility loci for generalized vitiligo

    PubMed Central

    Jin, Ying; Birlea, Stanca A; Fain, Pamela R; Ferrara, Tracey M; Ben, Songtao; Riccardi, Sheri L; Cole, Joanne B; Gowan, Katherine; Holland, Paulene J; Bennett, Dorothy C; Luiten, Rosalie M; Wolkerstorfer, Albert; van der Veen, JP Wietze; Hartmann, Anke; Eichner, Saskia; Schuler, Gerold; van Geel, Nanja; Lambert, Jo; Kemp, E Helen; Gawkrodger, David J; Weetman, Anthony P; Taïeb, Alain; Jouary, Thomas; Ezzedine, Khaled; Wallace, Margaret R; McCormack, Wayne T; Picardo, Mauro; Leone, Giovanni; Overbeck, Andreas; Silverberg, Nanette B; Spritz, Richard A

    2012-01-01

    In previous linkage and genome-wide association studies we identified 17 susceptibility loci for generalized vitiligo. By a second genome-wide association study, meta-analysis, and independent replication study, we have now identified 13 additional vitiligo-associated loci, including OCA2-HERC2, a region of 16q24.3 containing MC1R, a region of chromosome 11q21 near TYR, several immunoregulatory loci including IFIH1, CD80, CLNK, BACH2, SLA, CASP7, CD44, IKZF4, SH2B3, and a region of 22q13.2 where the causal gene remains uncertain. Functional pathway analysis shows that most vitiligo susceptibility loci encode immunoregulatory proteins or melanocyte components that likely mediate immune targeting and genetic relationships among vitiligo, malignant melanoma, and normal variation of eye, skin, and hair color. PMID:22561518

  1. Sample reproducibility of genetic association using different multimarker TDTs in genome-wide association studies: characterization and a new approach.

    PubMed

    Abad-Grau, Mara M; Medina-Medina, Nuria; Montes-Soldado, Rosana; Matesanz, Fuencisla; Bafna, Vineet

    2012-01-01

    Multimarker Transmission/Disequilibrium Tests (TDTs) are very robust association tests to population admixture and structure which may be used to identify susceptibility loci in genome-wide association studies. Multimarker TDTs using several markers may increase power by capturing high-degree associations. However, there is also a risk of spurious associations and power reduction due to the increase in degrees of freedom. In this study we show that associations found by tests built on simple null hypotheses are highly reproducible in a second independent data set regardless the number of markers. As a test exhibiting this feature to its maximum, we introduce the multimarker 2-Groups TDT (mTDT(2G)), a test which under the hypothesis of no linkage, asymptotically follows a χ2 distribution with 1 degree of freedom regardless the number of markers. The statistic requires the division of parental haplotypes into two groups: disease susceptibility and disease protective haplotype groups. We assessed the test behavior by performing an extensive simulation study as well as a real-data study using several data sets of two complex diseases. We show that mTDT(2G) test is highly efficient and it achieves the highest power among all the tests used, even when the null hypothesis is tested in a second independent data set. Therefore, mTDT(2G) turns out to be a very promising multimarker TDT to perform genome-wide searches for disease susceptibility loci that may be used as a preprocessing step in the construction of more accurate genetic models to predict individual susceptibility to complex diseases.

  2. Candidate genes for obesity-susceptibility show enriched association within a large genome-wide association study for BMI

    PubMed Central

    Vimaleswaran, Karani S.; Tachmazidou, Ioanna; Zhao, Jing Hua; Hirschhorn, Joel N.; Dudbridge, Frank; Loos, Ruth J.F.

    2012-01-01

    Before the advent of genome-wide association studies (GWASs), hundreds of candidate genes for obesity-susceptibility had been identified through a variety of approaches. We examined whether those obesity candidate genes are enriched for associations with body mass index (BMI) compared with non-candidate genes by using data from a large-scale GWAS. A thorough literature search identified 547 candidate genes for obesity-susceptibility based on evidence from animal studies, Mendelian syndromes, linkage studies, genetic association studies and expression studies. Genomic regions were defined to include the genes ±10 kb of flanking sequence around candidate and non-candidate genes. We used summary statistics publicly available from the discovery stage of the genome-wide meta-analysis for BMI performed by the genetic investigation of anthropometric traits consortium in 123 564 individuals. Hypergeometric, rank tail-strength and gene-set enrichment analysis tests were used to test for the enrichment of association in candidate compared with non-candidate genes. The hypergeometric test of enrichment was not significant at the 5% P-value quantile (P = 0.35), but was nominally significant at the 25% quantile (P = 0.015). The rank tail-strength and gene-set enrichment tests were nominally significant for the full set of genes and borderline significant for the subset without SNPs at P < 10−7. Taken together, the observed evidence for enrichment suggests that the candidate gene approach retains some value. However, the degree of enrichment is small despite the extensive number of candidate genes and the large sample size. Studies that focus on candidate genes have only slightly increased chances of detecting associations, and are likely to miss many true effects in non-candidate genes, at least for obesity-related traits. PMID:22791748

  3. Adjusted P values for genome-wide scans.

    PubMed Central

    Lystig, Theodore C

    2003-01-01

    Genome-wide scans for quantitative trait loci (QTL) have traditionally been summarized with plots of logarithm of odds (LOD) scores. A valuable modification is to supplement such plots with an additional vertical axis displaying quantiles of adjusted P values and labeling local maxima of the LOD scores with location-specific adjusted P values. This provides a visible gradation of genome-wide significance for the LOD score curve, instead of the stark dichotomy that a single threshold yields. Adjusted P values give genome-wide significance of individual LOD scores and are obtained through a straightforward modification of the familiar algorithm for generating permutation-based thresholds. PMID:12930772

  4. Natural selection on functional modules, a genome-wide analysis.

    PubMed

    Serra, François; Arbiza, Leonardo; Dopazo, Joaquín; Dopazo, Hernán

    2011-03-01

    Classically, the functional consequences of natural selection over genomes have been analyzed as the compound effects of individual genes. The current paradigm for large-scale analysis of adaptation is based on the observed significant deviations of rates of individual genes from neutral evolutionary expectation. This approach, which assumed independence among genes, has not been able to identify biological functions significantly enriched in positively selected genes in individual species. Alternatively, pooling related species has enhanced the search for signatures of selection. However, grouping signatures does not allow testing for adaptive differences between species. Here we introduce the Gene-Set Selection Analysis (GSSA), a new genome-wide approach to test for evidences of natural selection on functional modules. GSSA is able to detect lineage specific evolutionary rate changes in a notable number of functional modules. For example, in nine mammal and Drosophilae genomes GSSA identifies hundreds of functional modules with significant associations to high and low rates of evolution. Many of the detected functional modules with high evolutionary rates have been previously identified as biological functions under positive selection. Notably, GSSA identifies conserved functional modules with many positively selected genes, which questions whether they are exclusively selected for fitting genomes to environmental changes. Our results agree with previous studies suggesting that adaptation requires positive selection, but not every mutation under positive selection contributes to the adaptive dynamical process of the evolution of species.

  5. Genome-Wide Specific Selection in Three Domestic Sheep Breeds.

    PubMed

    Wang, Huihua; Zhang, Li; Cao, Jiaxve; Wu, Mingming; Ma, Xiaomeng; Liu, Zhen; Liu, Ruizao; Zhao, Fuping; Wei, Caihong; Du, Lixin

    2015-01-01

    Commercial sheep raised for mutton grow faster than traditional Chinese sheep breeds. Here, we aimed to evaluate genetic selection among three different types of sheep breed: two well-known commercial mutton breeds and one indigenous Chinese breed. We first combined locus-specific branch lengths and di statistical methods to detect candidate regions targeted by selection in the three different populations. The results showed that the genetic distances reached at least medium divergence for each pairwise combination. We found these two methods were highly correlated, and identified many growth-related candidate genes undergoing artificial selection. For production traits, APOBR and FTO are associated with body mass index. For meat traits, ALDOA, STK32B and FAM190A are related to marbling. For reproduction traits, CCNB2 and SLC8A3 affect oocyte development. We also found two well-known genes, GHR (which affects meat production and quality) and EDAR (associated with hair thickness) were associated with German mutton merino sheep. Furthermore, four genes (POL, RPL7, MSL1 and SHISA9) were associated with pre-weaning gain in our previous genome-wide association study. Our results indicated that combine locus-specific branch lengths and di statistical approaches can reduce the searching ranges for specific selection. And we got many credible candidate genes which not only confirm the results of previous reports, but also provide a suite of novel candidate genes in defined breeds to guide hybridization breeding.

  6. Genome-Wide Specific Selection in Three Domestic Sheep Breeds

    PubMed Central

    Cao, Jiaxve; Wu, Mingming; Ma, Xiaomeng; Liu, Zhen; Liu, Ruizao; Zhao, Fuping; Wei, Caihong; Du, Lixin

    2015-01-01

    Background Commercial sheep raised for mutton grow faster than traditional Chinese sheep breeds. Here, we aimed to evaluate genetic selection among three different types of sheep breed: two well-known commercial mutton breeds and one indigenous Chinese breed. Results We first combined locus-specific branch lengths and di statistical methods to detect candidate regions targeted by selection in the three different populations. The results showed that the genetic distances reached at least medium divergence for each pairwise combination. We found these two methods were highly correlated, and identified many growth-related candidate genes undergoing artificial selection. For production traits, APOBR and FTO are associated with body mass index. For meat traits, ALDOA, STK32B and FAM190A are related to marbling. For reproduction traits, CCNB2 and SLC8A3 affect oocyte development. We also found two well-known genes, GHR (which affects meat production and quality) and EDAR (associated with hair thickness) were associated with German mutton merino sheep. Furthermore, four genes (POL, RPL7, MSL1 and SHISA9) were associated with pre-weaning gain in our previous genome-wide association study. Conclusions Our results indicated that combine locus-specific branch lengths and di statistical approaches can reduce the searching ranges for specific selection. And we got many credible candidate genes which not only confirm the results of previous reports, but also provide a suite of novel candidate genes in defined breeds to guide hybridization breeding. PMID:26083354

  7. Genome-wide genetic investigation of serological measures of common infections

    PubMed Central

    Rubicz, Rohina; Yolken, Robert; Drigalenko, Eugene; Carless, Melanie A; Dyer, Thomas D; Kent Jr, Jack; Curran, Joanne E; Johnson, Matthew P; Cole, Shelley A; Fowler, Sharon P; Arya, Rector; Puppala, Sobha; Almasy, Laura; Moses, Eric K; Kraig, Ellen; Duggirala, Ravindranath; Blangero, John; Leach, Charles T; Göring, Harald HH

    2015-01-01

    Populations and individuals differ in susceptibility to infections because of a number of factors, including host genetic variation. We previously demonstrated that differences in antibody titer, which reflect infection history, are significantly heritable. Here we attempt to identify the genetic factors influencing variation in these serological phenotypes. Blood samples from >1300 Mexican Americans were quantified for IgG antibody level against 12 common infections, selected on the basis of their reported role in cardiovascular disease risk: Chlamydia pneumoniae; Helicobacter pylori; Toxoplasma gondii; cytomegalovirus; herpes simplex I virus; herpes simplex II virus; human herpesvirus 6 (HHV6); human herpesvirus 8 (HHV8); varicella zoster virus; hepatitis A virus (HAV); influenza A virus; and influenza B virus. Pathogen-specific quantitative antibody levels were analyzed, as were three measures of pathogen burden. Genome-wide linkage and joint linkage and association analyses were performed using ~1 million SNPs. Significant linkage (lod scores >3.0) was obtained for HHV6 (on chromosome 7), HHV8 (on chromosome 6), and HAV (on chromosome 13). SNP rs4812712 on chromosome 20 was significantly associated with C. pneumoniae (P=5.3 × 10−8). However, no genome-wide significant loci were obtained for the other investigated antibodies. We conclude that it is possible to localize host genetic factors influencing some of these antibody traits, but that further larger-scale investigations will be required to elucidate the genetic mechanisms contributing to variation in antibody levels. PMID:25758998

  8. Human QTL linkage mapping.

    PubMed

    Almasy, Laura; Blangero, John

    2009-06-01

    Human quantitative trait locus (QTL) linkage mapping, although based on classical statistical genetic methods that have been around for many years, has been employed for genome-wide screening for only the last 10-15 years. In this time, there have been many success stories, ranging from QTLs that have been replicated in independent studies to those for which one or more genes underlying the linkage peak have been identified to a few with specific functional variants that have been confirmed in in vitro laboratory assays. Despite these successes, there is a general perception that linkage approaches do not work for complex traits, possibly because many human QTL linkage studies have been limited in sample size and have not employed the family configurations that maximize the power to detect linkage. We predict that human QTL linkage studies will continue to be productive for the next several years, particularly in combination with RNA expression level traits that are showing evidence of regulatory QTLs of large effect sizes and in combination with high-density genome-wide SNP panels. These SNP panels are being used to identify QTLs previously localized by linkage and linkage results are being used to place informative priors on genome-wide association studies.

  9. Genome-Wide Association Study of Receptive Language Ability of 12-Year-Olds

    PubMed Central

    Harlaar, Nicole; Meaburn, Emma L.; Hayiou-Thomas, Marianna E.; Davis, Oliver S. P.; Docherty, Sophia; Hanscombe, Ken B.; Haworth, Claire M. A.; Price, Thomas S.; Trzaskowski, Maciej; Dale, Philip S.; Plomin, Robert

    2014-01-01

    Purpose Researchers have previously shown that individual differences in measures of receptive language ability at age 12 are highly heritable. In the current study, the authors attempted to identify some of the genes responsible for the heritability of receptive language ability using a genome-wide association approach. Method The authors administered 4 Internet-based measures of receptive language (vocabulary, semantics, syntax, and pragmatics) to a sample of 2,329 twelve-year-olds for whom DNA and genome-wide genotyping were available. Nearly 700,000 single-nucleotide polymorphisms (SNPs) and 1 million imputed SNPs were included in a genome-wide association analysis of receptive language composite scores. Results No SNP associations met the demanding criterion of genome-wide significance that corrects for multiple testing across the genome (p < 5 × 10–8). The strongest SNP association did not replicate in an additional sample of 2,639 twelve-year-olds. Conclusions These results indicate that individual differences in receptive language ability in the general population do not reflect common genetic variants that account for more than 3% of the phenotypic variance. The search for genetic variants associated with language skill will require larger samples and additional methods to identify and functionally characterize the full spectrum of risk variants. PMID:24687471

  10. LD Score regression distinguishes confounding from polygenicity in genome-wide association studies.

    PubMed

    Bulik-Sullivan, Brendan K; Loh, Po-Ru; Finucane, Hilary K; Ripke, Stephan; Yang, Jian; Patterson, Nick; Daly, Mark J; Price, Alkes L; Neale, Benjamin M

    2015-03-01

    Both polygenicity (many small genetic effects) and confounding biases, such as cryptic relatedness and population stratification, can yield an inflated distribution of test statistics in genome-wide association studies (GWAS). However, current methods cannot distinguish between inflation from a true polygenic signal and bias. We have developed an approach, LD Score regression, that quantifies the contribution of each by examining the relationship between test statistics and linkage disequilibrium (LD). The LD Score regression intercept can be used to estimate a more powerful and accurate correction factor than genomic control. We find strong evidence that polygenicity accounts for the majority of the inflation in test statistics in many GWAS of large sample size.

  11. Multiple genome-wide analyses of smoking behavior in the Framingham Heart Study.

    PubMed

    Goode, Ellen L; Badzioch, Michael D; Kim, Helen; Gagnon, France; Rozek, Laura S; Edwards, Karen L; Jarvik, Gail P

    2003-12-31

    Cigarette smoking behavior may have a genetic basis. We assessed evidence for quantitative trait loci (QTLs) affecting the maximum number of cigarettes smoked per day, a trait meant to quantify this behavior, using data collected over 40 years as part of the Framingham Heart Study's original and offspring cohorts. Heritability was estimated to be approximately 21% using variance components (VC) methods (SOLAR), while oligogenic linkage and segregation analysis based on Bayesian Markov chain Monte Carlo (MCMC) methods (LOKI) estimated a mean of two large QTLs contributing approximately 28% and 20%, respectively, to the trait's variance. Genome-wide parametric (FASTLINK) and VC linkage analyses (SOLAR) revealed several LOD scores greater than 1.0, with peak LOD scores using both methods on chromosomes 2, 17, and 20; multi-point MCMC methods followed up on these chromosomes. The most robust linkage results were for a QTL between 65 and 84 cM on chromosome 20 with signals from multiple sex- and age-adjusted analyses including two-point LOD scores of 1.30 (parametric) and 1.07 (heritability = 0.17, VC) at 70.51 cM, a multi-point LOD score of 1.50 (heritability = 0.20, VC) at 84 cM, and an intensity ratio of 12.0 (MCMC) at 65 cM. Familial aggregation of the maximum number of cigarettes smoked per day was consistent with a genetic component to this behavior, and oligogenic segregation analyses using MCMC suggested two important QTLs. Linkage signals on chromosome 20 between 65 and 84 cM were seen using multiple analytical methods. No linkage result, however, met genome-wide statistical significance criteria, and the true relationship between these regions and smoking behavior remains unclear.

  12. Multiple genome-wide analyses of smoking behavior in the Framingham Heart Study

    PubMed Central

    Goode, Ellen L; Badzioch, Michael D; Kim, Helen; Gagnon, France; Rozek, Laura S; Edwards, Karen L; Jarvik, Gail P

    2003-01-01

    Background Cigarette smoking behavior may have a genetic basis. We assessed evidence for quantitative trait loci (QTLs) affecting the maximum number of cigarettes smoked per day, a trait meant to quantify this behavior, using data collected over 40 years as part of the Framingham Heart Study's original and offspring cohorts. Results Heritability was estimated to be approximately 21% using variance components (VC) methods (SOLAR), while oligogenic linkage and segregation analysis based on Bayesian Markov chain Monte Carlo (MCMC) methods (LOKI) estimated a mean of two large QTLs contributing approximately 28% and 20%, respectively, to the trait's variance. Genome-wide parametric (FASTLINK) and VC linkage analyses (SOLAR) revealed several LOD scores greater than 1.0, with peak LOD scores using both methods on chromosomes 2, 17, and 20; multi-point MCMC methods followed up on these chromosomes. The most robust linkage results were for a QTL between 65 and 84 cM on chromosome 20 with signals from multiple sex- and age-adjusted analyses including two-point LOD scores of 1.30 (parametric) and 1.07 (heritability = 0.17, VC) at 70.51 cM, a multi-point LOD score of 1.50 (heritability = 0.20, VC) at 84 cM, and an intensity ratio of 12.0 (MCMC) at 65 cM. Conclusion Familial aggregation of the maximum number of cigarettes smoked per day was consistent with a genetic component to this behavior, and oligogenic segregation analyses using MCMC suggested two important QTLs. Linkage signals on chromosome 20 between 65 and 84 cM were seen using multiple analytical methods. No linkage result, however, met genome-wide statistical significance criteria, and the true relationship between these regions and smoking behavior remains unclear. PMID:14975170

  13. Genome-wide evidence for speciation with gene flow in Heliconius butterflies.

    PubMed

    Martin, Simon H; Dasmahapatra, Kanchon K; Nadeau, Nicola J; Salazar, Camilo; Walters, James R; Simpson, Fraser; Blaxter, Mark; Manica, Andrea; Mallet, James; Jiggins, Chris D

    2013-11-01

    Most speciation events probably occur gradually, without complete and immediate reproductive isolation, but the full extent of gene flow between diverging species has rarely been characterized on a genome-wide scale. Documenting the extent and timing of admixture between diverging species can clarify the role of geographic isolation in speciation. Here we use new methodology to quantify admixture at different stages of divergence in Heliconius butterflies, based on whole-genome sequences of 31 individuals. Comparisons between sympatric and allopatric populations of H. melpomene, H. cydno, and H. timareta revealed a genome-wide trend of increased shared variation in sympatry, indicative of pervasive interspecific gene flow. Up to 40% of 100-kb genomic windows clustered by geography rather than by species, demonstrating that a very substantial fraction of the genome has been shared between sympatric species. Analyses of genetic variation shared over different time intervals suggested that admixture between these species has continued since early in speciation. Alleles shared between species during recent time intervals displayed higher levels of linkage disequilibrium than those shared over longer time intervals, suggesting that this admixture took place at multiple points during divergence and is probably ongoing. The signal of admixture was significantly reduced around loci controlling divergent wing patterns, as well as throughout the Z chromosome, consistent with strong selection for Müllerian mimicry and with known Z-linked hybrid incompatibility. Overall these results show that species divergence can occur in the face of persistent and genome-wide admixture over long periods of time.

  14. The First Pilot Genome-Wide Gene-Environment Study of Depression in the Japanese Population

    PubMed Central

    Otowa, Takeshi; Kawamura, Yoshiya; Tsutsumi, Akizumi; Kawakami, Norito; Kan, Chiemi; Shimada, Takafumi; Umekage, Tadashi; Kasai, Kiyoto; Tokunaga, Katsushi; Sasaki, Tsukasa

    2016-01-01

    Stressful events have been identified as a risk factor for depression. Although gene–environment (G × E) interaction in a limited number of candidate genes has been explored, no genome-wide search has been reported. The aim of the present study is to identify genes that influence the association of stressful events with depression. Therefore, we performed a genome-wide G × E interaction analysis in the Japanese population. A genome-wide screen with 320 subjects was performed using the Affymetrix Genome-Wide Human Array 6.0. Stressful life events were assessed using the Social Readjustment Rating Scale (SRRS) and depression symptoms were assessed with self-rating questionnaires using the Center for Epidemiologic Studies Depression (CES-D) scale. The p values for interactions between single nucleotide polymorphisms (SNPs) and stressful events were calculated using the linear regression model adjusted for sex and age. After quality control of genotype data, a total of 534,848 SNPs on autosomal chromosomes were further analyzed. Although none surpassed the level of the genome-wide significance, a marginal significant association of interaction between SRRS and rs10510057 with depression were found (p = 4.5 × 10−8). The SNP is located on 10q26 near Regulators of G-protein signaling 10 (RGS10), which encodes a regulatory molecule involved in stress response. When we investigated a similar G × E interaction between depression (K6 scale) and work-related stress in an independent sample (n = 439), a significant G × E effect on depression was observed (p = 0.015). Our findings suggest that rs10510057, interacting with stressors, may be involved in depression risk. Incorporating G × E interaction into GWAS can contribute to find susceptibility locus that are potentially missed by conventional GWAS. PMID:27529621

  15. Genome-wide Association and Functional Studies Identify a Role for IGFBP3 in Hip Osteoarthritis

    PubMed Central

    Evans, Daniel S.; Cailotto, Frederic; Parimi, Neeta; Valdes, Ana M.; Castaño-Betancourt, Martha C.; Liu, Youfang; Kaplan, Robert C.; Bidlingmaier, Martin; Vasan, Ramachandran S.; Teumer, Alexander; Tranah, Gregory J.; Nevitt, Michael C.; Cummings, Steven R.; Orwoll, Eric S.; Barrett-Connor, Elizabeth; Renner, Jordan B.; Jordan, Joanne M.; Doherty, Michael; Doherty, Sally A.; Uitterlinden, Andre G.; van Meurs, Joyce B.J.; Spector, Tim D.; Lories, Rik J.; Lane, Nancy E.

    2015-01-01

    Objectives To identify genetic associations with hip osteoarthritis (HOA), we performed a meta-analysis of genome-wide association studies (GWAS) of HOA. Methods The GWAS meta-analysis included approximately 2.5 million imputed HapMap single nucleotide polymorphisms (SNPs). HOA cases and controls defined radiographically and by total hip replacement were selected from the Osteoporotic Fractures in Men (MrOS) Study and the Study of Osteoporotic Fractures (SOF) (654 cases and 4697 controls, combined). Replication of genome-wide significant SNP associations (P-value ≤ 5x10−8) was examined in five studies (3243 cases and 6891 controls, combined). Functional studies were performed using in vitro models of chondrogenesis and osteogenesis. Results The A allele of rs788748, located 65 kb upstream of the IGFBP3 gene, was associated with lower HOA odds at the genome-wide significance level in the discovery stage (OR = 0.71, P-value = 2x10−8). The association replicated in five studies (OR = 0.92, P-value = 0.020), but the joint analysis of discovery and replication results was not genome-wide significant (P-value = 1x10−6). In separate study populations, the rs788748 A allele was also associated with lower circulating IGFBP3 protein levels (P-value = 4x10−13), suggesting that this SNP or a variant in linkage disequilibrium (LD) could be an IGFBP3 regulatory variant. Results from functional studies were consistent with association results. Chondrocyte hypertrophy, a deleterious event in OA pathogenesis, was largely prevented upon IGFBP3 knockdown in chondrocytes. Furthermore, IGFBP3 overexpression induced cartilage catabolism and osteogenic differentiation. Conclusions Results from GWAS and functional studies provided suggestive links between IGFBP3 and HOA. PMID:24928840

  16. Significant Locus and Metabolic Genetic Correlations Revealed in Genome-Wide Association Study of Anorexia Nervosa.

    PubMed

    Duncan, Laramie; Yilmaz, Zeynep; Gaspar, Helena; Walters, Raymond; Goldstein, Jackie; Anttila, Verneri; Bulik-Sullivan, Brendan; Ripke, Stephan; Thornton, Laura; Hinney, Anke; Daly, Mark; Sullivan, Patrick F; Zeggini, Eleftheria; Breen, Gerome; Bulik, Cynthia M

    2017-09-01

    The authors conducted a genome-wide association study of anorexia nervosa and calculated genetic correlations with a series of psychiatric, educational, and metabolic phenotypes. Following uniform quality control and imputation procedures using the 1000 Genomes Project (phase 3) in 12 case-control cohorts comprising 3,495 anorexia nervosa cases and 10,982 controls, the authors performed standard association analysis followed by a meta-analysis across cohorts. Linkage disequilibrium score regression was used to calculate genome-wide common variant heritability (single-nucleotide polymorphism [SNP]-based heritability [h(2)SNP]), partitioned heritability, and genetic correlations (rg) between anorexia nervosa and 159 other phenotypes. Results were obtained for 10,641,224 SNPs and insertion-deletion variants with minor allele frequencies >1% and imputation quality scores >0.6. The h(2)SNP of anorexia nervosa was 0.20 (SE=0.02), suggesting that a substantial fraction of the twin-based heritability arises from common genetic variation. The authors identified one genome-wide significant locus on chromosome 12 (rs4622308) in a region harboring a previously reported type 1 diabetes and autoimmune disorder locus. Significant positive genetic correlations were observed between anorexia nervosa and schizophrenia, neuroticism, educational attainment, and high-density lipoprotein cholesterol, and significant negative genetic correlations were observed between anorexia nervosa and body mass index, insulin, glucose, and lipid phenotypes. Anorexia nervosa is a complex heritable phenotype for which this study has uncovered the first genome-wide significant locus. Anorexia nervosa also has large and significant genetic correlations with both psychiatric phenotypes and metabolic traits. The study results encourage a reconceptualization of this frequently lethal disorder as one with both psychiatric and metabolic etiology.

  17. A genome-wide association study of sporadic ALS in a homogenous Irish population.

    PubMed

    Cronin, Simon; Berger, Stephen; Ding, Jinhui; Schymick, Jennifer C; Washecka, Nicole; Hernandez, Dena G; Greenway, Matthew J; Bradley, Daniel G; Traynor, Bryan J; Hardiman, Orla

    2008-03-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive limb or bulbar weakness. Efforts to elucidate the disease-associated loci have to date produced conflicting results. One strategy to improve power in genome-wide studies is to genotype a genetically homogenous population. Such a population exhibits extended linkage disequilibrium (LD) and lower allelic heterogeneity to facilitate disease gene mapping. We sought to identify associated variants for ALS in the Irish, a stable population of relatively homogenous genetic background, and to replicate these findings in larger genetically out-bred populations. We conducted a genome-wide association study in 432 Irish individuals using Illumina HumanHap 550K single nucleotide polymorphism chips. We demonstrated extended LD and increased homogeneity in the Irish sample when compared to an out-bred population of mixed European ancestry. The Irish scan identified 35 loci associated with P-values below 0.0001. For replication, we identified seven chromosomal regions commonly associated in a joint analysis of genome-wide data on 958 ALS cases and 932 controls from Ireland and the previously published datasets from the US and The Netherlands. When pooled, the strongest association was a variant in the gene encoding DPP6, a component of type A neuronal transmembrane potassium channels. Further confirmation of the candidate loci is warranted in additional genome-wide datasets. We have made our individual genotyping data publicly available, contributing to a powerful world-wide resource to refine our understanding of the genetics of sporadic ALS.

  18. Genome-Wide Architecture of Disease Resistance Genes in Lettuce.

    PubMed

    Christopoulou, Marilena; Wo, Sebastian Reyes-Chin; Kozik, Alex; McHale, Leah K; Truco, Maria-Jose; Wroblewski, Tadeusz; Michelmore, Richard W

    2015-10-08

    Genome-wide motif searches identified 1134 genes in the lettuce reference genome of cv. Salinas that are potentially involved in pathogen recognition, of which 385 were predicted to encode nucleotide binding-leucine rich repeat receptor (NLR) proteins. Using a maximum-likelihood approach, we grouped the NLRs into 25 multigene families and 17 singletons. Forty-one percent of these NLR-encoding genes belong to three families, the largest being RGC16 with 62 genes in cv. Salinas. The majority of NLR-encoding genes are located in five major resistance clusters (MRCs) on chromosomes 1, 2, 3, 4, and 8 and cosegregate with multiple disease resistance phenotypes. Most MRCs contain primarily members of a single NLR gene family but a few are more complex. MRC2 spans 73 Mb and contains 61 NLRs of six different gene families that cosegregate with nine disease resistance phenotypes. MRC3, which is 25 Mb, contains 22 RGC21 genes and colocates with Dm13. A library of 33 transgenic RNA interference tester stocks was generated for functional analysis of NLR-encoding genes that cosegregated with disease resistance phenotypes in each of the MRCs. Members of four NLR-encoding families, RGC1, RGC2, RGC21, and RGC12 were shown to be required for 16 disease resistance phenotypes in lettuce. The general composition of MRCs is conserved across different genotypes; however, the specific repertoire of NLR-encoding genes varied particularly of the rapidly evolving Type I genes. These tester stocks are valuable resources for future analyses of additional resistance phenotypes. Copyright © 2015 Christopoulou et al.

  19. Genome-Wide Architecture of Disease Resistance Genes in Lettuce

    PubMed Central

    Christopoulou, Marilena; Wo, Sebastian Reyes-Chin; Kozik, Alex; McHale, Leah K.; Truco, Maria-Jose; Wroblewski, Tadeusz; Michelmore, Richard W.

    2015-01-01

    Genome-wide motif searches identified 1134 genes in the lettuce reference genome of cv. Salinas that are potentially involved in pathogen recognition, of which 385 were predicted to encode nucleotide binding-leucine rich repeat receptor (NLR) proteins. Using a maximum-likelihood approach, we grouped the NLRs into 25 multigene families and 17 singletons. Forty-one percent of these NLR-encoding genes belong to three families, the largest being RGC16 with 62 genes in cv. Salinas. The majority of NLR-encoding genes are located in five major resistance clusters (MRCs) on chromosomes 1, 2, 3, 4, and 8 and cosegregate with multiple disease resistance phenotypes. Most MRCs contain primarily members of a single NLR gene family but a few are more complex. MRC2 spans 73 Mb and contains 61 NLRs of six different gene families that cosegregate with nine disease resistance phenotypes. MRC3, which is 25 Mb, contains 22 RGC21 genes and colocates with Dm13. A library of 33 transgenic RNA interference tester stocks was generated for functional analysis of NLR-encoding genes that cosegregated with disease resistance phenotypes in each of the MRCs. Members of four NLR-encoding families, RGC1, RGC2, RGC21, and RGC12 were shown to be required for 16 disease resistance phenotypes in lettuce. The general composition of MRCs is conserved across different genotypes; however, the specific repertoire of NLR-encoding genes varied particularly of the rapidly evolving Type I genes. These tester stocks are valuable resources for future analyses of additional resistance phenotypes. PMID:26449254

  20. Machine learning in genome-wide association studies.

    PubMed

    Szymczak, Silke; Biernacka, Joanna M; Cordell, Heather J; González-Recio, Oscar; König, Inke R; Zhang, Heping; Sun, Yan V

    2009-01-01

    Recently, genome-wide association studies have substantially expanded our knowledge about genetic variants that influence the susceptibility to complex diseases. Although standard statistical tests for each single-nucleotide polymorphism (SNP) separately are able to capture main genetic effects, different approaches are necessary to identify SNPs that influence disease risk jointly or in complex interactions. Experimental and simulated genome-wide SNP data provided by the Genetic Analysis Workshop 16 afforded an opportunity to analyze the applicability and benefit of several machine learning methods. Penalized regression, ensemble methods, and network analyses resulted in several new findings while known and simulated genetic risk variants were also identified. In conclusion, machine learning approaches are promising complements to standard single-and multi-SNP analysis methods for understanding the overall genetic architecture of complex human diseases. However, because they are not optimized for genome-wide SNP data, improved implementations and new variable selection procedures are required. (c) 2009 Wiley-Liss, Inc.

  1. An efficient multi-locus mixed-model approach for genome-wide association studies in structured populations.

    PubMed

    Segura, Vincent; Vilhjálmsson, Bjarni J; Platt, Alexander; Korte, Arthur; Seren, Ümit; Long, Quan; Nordborg, Magnus

    2012-06-17

    Population structure causes genome-wide linkage disequilibrium between unlinked loci, leading to statistical confounding in genome-wide association studies. Mixed models have been shown to handle the confounding effects of a diffuse background of large numbers of loci of small effect well, but they do not always account for loci of larger effect. Here we propose a multi-locus mixed model as a general method for mapping complex traits in structured populations. Simulations suggest that our method outperforms existing methods in terms of power as well as false discovery rate. We apply our method to human and Arabidopsis thaliana data, identifying new associations and evidence for allelic heterogeneity. We also show how a priori knowledge from an A. thaliana linkage mapping study can be integrated into our method using a Bayesian approach. Our implementation is computationally efficient, making the analysis of large data sets (n > 10,000) practicable.

  2. A genome-wide scan for human obesity genes reveals a major susceptibility locus on chromosome 10.

    PubMed

    Hager, J; Dina, C; Francke, S; Dubois, S; Houari, M; Vatin, V; Vaillant, E; Lorentz, N; Basdevant, A; Clement, K; Guy-Grand, B; Froguel, P

    1998-11-01

    Obesity, a common multifactorial disorder, is a major risk factor for type 2 diabetes, hypertension and coronary heart disease (CHD). According to the definition of the World Health Organization (WHO), approximately 6-10% of the population in Westernized countries are considered obese. Epidemiological studies have shown that 30-70% of the variation in body weight may be attributable to genetic factors. To date, two genome-wide scans using different obesity-related quantitative traits have provided candidate regions for obesity. We have undertaken a genome-wide scan in affected sibpairs to identify chromosomal regions linked to obesity in a collection of French families. Model-free multipoint linkage analyses revealed evidence for linkage to a region on chromosome 10p (MLS=4.85). Two further loci on chromosomes 5cen-q and 2p showed suggestive evidence for linkage of serum leptin levels in a genome-wide context. The peak on chromosome 2 coincided with the region containing the gene (POMC) encoding pro-opiomelanocortin, a locus previously linked to leptin levels and fat mass in a Mexican-American population and shown to be mutated in obese humans. Our results suggest that there is a major gene on chromosome 10p implicated in the development of human obesity, and the existence of two further loci influencing leptin levels.

  3. Genome-wide association mapping of soybean aphid resistance traits

    USDA-ARS?s Scientific Manuscript database

    Soybean aphid is the most damaging insect pest of soybean in the Upper Midwest and is primarily controlled by insecticides. Soybean aphid resistance (i.e., Rag genes) has been documented in some soybean lines at chromosomes 6, 7, 13, and 16, but more sources of resistance are needed. Genome-wide ass...

  4. A super powerful method for genome wide association study

    USDA-ARS?s Scientific Manuscript database

    Genome-Wide Association Studies shed light on the identification of genes underlying human diseases and agriculturally important traits. This potential has been shadowed by false positive findings. The Mixed Linear Model (MLM) method is flexible enough to simultaneously incorporate population struct...

  5. Genome-wide characterization of maize miRNA genes

    USDA-ARS?s Scientific Manuscript database

    MicroRNAs (miRNAs) are small non-coding RNAs that play essential roles in plant growth and development. We conducted a genome-wide survey of maize miRNA genes, characterizing their structure, expression, and evolution. Computational approaches based on homology and secondary structure modeling ident...

  6. Genome-wide association studies in maize: praise and stargaze

    USDA-ARS?s Scientific Manuscript database

    Genome-wide association study (GWAS) has appeared as a widespread strategy in decoding genotype-phenotype associations in many species thanks to technical advances in next-generation sequencing (NGS) applications. Maize is an ideal crop for GWAS and significant progress has been made in the last dec...

  7. Genome-wide association study identifies five new schizophrenia loci

    PubMed Central

    2012-01-01

    We examined the role of common genetic variation in schizophrenia in a genome-wide association study of substantial size: a stage 1 discovery sample of 21,856 individuals of European ancestry and a stage 2 replication sample of 29,839 independent subjects. The combined stage 1 and 2 analysis yielded genome-wide significant associations with schizophrenia for seven loci, five of which are new (1p21.3, 2q32.3, 8p23.2, 8q21.3 and 10q24.32-q24.33) and two of which have been previously implicated (6p21.32-p22.1 and 18q21.2). The strongest new finding (P = 1.6 × 10−11) was with rs1625579 within an intron of a putative primary transcript for MIR137 (microRNA 137), a known regulator of neuronal development. Four other schizophrenia loci achieving genome-wide significance contain predicted targets of MIR137, suggesting MIR137-mediated dysregulation as a previously unknown etiologic mechanism in schizophrenia. In a joint analysis with a bipolar disorder sample (16,374 affected individuals and 14,044 controls), three loci reached genome-wide significance: CACNA1C (rs4765905, P = 7.0 × 10−9), ANK3 (rs10994359, P = 2.5 × 10−8) and the ITIH3-ITIH4 region (rs2239547, P = 7.8 × 10−9). PMID:21926974

  8. Chromosome 9p21 in Amyotrophic Lateral Sclerosis in Finland: A Genome-Wide Association Study

    PubMed Central

    Laaksovirta, Hannu; Peuralinna, Terhi; Schymick, Jennifer C.; Scholz, Sonja W.; Lai, Shaoi-Lin; Myllykangas, Liisa; Sulkava, Raimo; Jansson, Lilja; Hernandez, Dena G.; Gibbs, J. Raphael; Nalls, Michael A.; Heckerman, David; Tienari, Pentti J.; Traynor, Bryan J.

    2010-01-01

    Introduction The genetic etiology of amyotrophic lateral sclerosis (ALS) is not well understood. Finland is a well-suited location for a genome-wide association study of ALS, as the incidence of the disease is one of the highest in the world, and because the genetic homogeneity of the Finnish population enhances the ability to detect risk loci. Methods We performed a genome-wide association study of 442 Finnish patients diagnosed with ALS, and 521 Finnish control subjects using Illumina genome-wide genotyping arrays. DNA was collected from patients attending an ALS specialty clinic that receives referrals from neurologists throughout Finland, whereas the control samples were obtained from a population-based study of elderly Finnish individuals. Individuals known to carry D90A alleles of the SOD1 gene (n = 40) were included in the final analysis as positive controls to determine if our GWAS was able to detect an association signal at this locus. Findings We identified two association peaks that exceeded genome-wide significance. One of these was located on chromosome 21q22 (rs13048019, p = 2·58×10−8) that corresponded to the known autosomal recessive D90A allele of the SOD1 gene. The other was detected in a 232kb block of linkage disequilibrium (rs3849942, p = 9·11×10−11) in a region of chromosome 9p that has been previously identified by linkage studies of ALS families. Within this region, we defined a 42-SNP haplotype that significantly increased risk of developing ALS (p = 4·2×10−33 among familial cases, odds ratio = 21·0, 95% CI = 11·2–39·1), and which overlapped with an association locus recently reported for fronto-temporal dementia (FTD). Based on the 93 familial ALS cases included in the analysis, population attributable risk percent for the chromosome 9p21 locus was 37.9% (95% CI, 27·7 – 48·1%), and for D90A homozygosity was 25·5% (95% CI, 16·9 – 34·1%). Interpretation In summary, we present evidence that the chromosome 9p21 ALS

  9. Genome-wide analysis of genetic susceptibility to language impairment in an isolated Chilean population

    PubMed Central

    Villanueva, Pia; Newbury, Dianne F; Jara, Lilian; De Barbieri, Zulema; Mirza, Ghazala; Palomino, Hernán M; Fernández, María Angélica; Cazier, Jean-Baptiste; Monaco, Anthony P; Palomino, Hernán

    2011-01-01

    Specific language impairment (SLI) is an unexpected deficit in the acquisition of language skills and affects between 5 and 8% of pre-school children. Despite its prevalence and high heritability, our understanding of the aetiology of this disorder is only emerging. In this paper, we apply genome-wide techniques to investigate an isolated Chilean population who exhibit an increased frequency of SLI. Loss of heterozygosity (LOH) mapping and parametric and non-parametric linkage analyses indicate that complex genetic factors are likely to underlie susceptibility to SLI in this population. Across all analyses performed, the most consistently implicated locus was on chromosome 7q. This locus achieved highly significant linkage under all three non-parametric models (max NPL=6.73, P=4.0 × 10−11). In addition, it yielded a HLOD of 1.24 in the recessive parametric linkage analyses and contained a segment that was homozygous in two affected individuals. Further, investigation of this region identified a two-SNP haplotype that occurs at an increased frequency in language-impaired individuals (P=0.008). We hypothesise that the linkage regions identified here, in particular that on chromosome 7, may contain variants that underlie the high prevalence of SLI observed in this isolated population and may be of relevance to other populations affected by language impairments. PMID:21248734

  10. Poor replication of candidate genes for major depressive disorder using genome-wide association data.

    PubMed

    Bosker, F J; Hartman, C A; Nolte, I M; Prins, B P; Terpstra, P; Posthuma, D; van Veen, T; Willemsen, G; DeRijk, R H; de Geus, E J; Hoogendijk, W J; Sullivan, P F; Penninx, B W; Boomsma, D I; Snieder, H; Nolen, W A

    2011-05-01

    Data from the Genetic Association Information Network (GAIN) genome-wide association study (GWAS) in major depressive disorder (MDD) were used to explore previously reported candidate gene and single-nucleotide polymorphism (SNP) associations in MDD. A systematic literature search of candidate genes associated with MDD in case-control studies was performed before the results of the GAIN MDD study became available. Measured and imputed candidate SNPs and genes were tested in the GAIN MDD study encompassing 1738 cases and 1802 controls. Imputation was used to increase the number of SNPs from the GWAS and to improve coverage of SNPs in the candidate genes selected. Tests were carried out for individual SNPs and the entire gene using different statistical approaches, with permutation analysis as the final arbiter. In all, 78 papers reporting on 57 genes were identified, from which 92 SNPs could be mapped. In the GAIN MDD study, two SNPs were associated with MDD: C5orf20 (rs12520799; P=0.038; odds ratio (OR) AT=1.10, 95% CI 0.95-1.29; OR TT=1.21, 95% confidence interval (CI) 1.01-1.47) and NPY (rs16139; P=0.034; OR C allele=0.73, 95% CI 0.55-0.97), constituting a direct replication of previously identified SNPs. At the gene level, TNF (rs76917; OR T=1.35, 95% CI 1.13-1.63; P=0.0034) was identified as the only gene for which the association with MDD remained significant after correction for multiple testing. For SLC6A2 (norepinephrine transporter (NET)) significantly more SNPs (19 out of 100; P=0.039) than expected were associated while accounting for the linkage disequilibrium (LD) structure. Thus, we found support for involvement in MDD for only four genes. However, given the number of candidate SNPs and genes that were tested, even these significant may well be false positives. The poor replication may point to publication bias and false-positive findings in previous candidate gene studies, and may also be related to heterogeneity of the MDD phenotype as well as

  11. Genome-Wide Meta-Analysis of Longitudinal Alcohol Consumption Across Youth and Early Adulthood.

    PubMed

    Adkins, Daniel E; Clark, Shaunna L; Copeland, William E; Kennedy, Martin; Conway, Kevin; Angold, Adrian; Maes, Hermine; Liu, Youfang; Kumar, Gaurav; Erkanli, Alaattin; Patkar, Ashwin A; Silberg, Judy; Brown, Tyson H; Fergusson, David M; Horwood, L John; Eaves, Lindon; van den Oord, Edwin J C G; Sullivan, Patrick F; Costello, E J

    2015-08-01

    The public health burden of alcohol is unevenly distributed across the life course, with levels of use, abuse, and dependence increasing across adolescence and peaking in early adulthood. Here, we leverage this temporal patterning to search for common genetic variants predicting developmental trajectories of alcohol consumption. Comparable psychiatric evaluations measuring alcohol consumption were collected in three longitudinal community samples (N=2,126, obs=12,166). Consumption-repeated measurements spanning adolescence and early adulthood were analyzed using linear mixed models, estimating individual consumption trajectories, which were then tested for association with Illumina 660W-Quad genotype data (866,099 SNPs after imputation and QC). Association results were combined across samples using standard meta-analysis methods. Four meta-analysis associations satisfied our pre-determined genome-wide significance criterion (FDR<0.1) and six others met our 'suggestive' criterion (FDR<0.2). Genome-wide significant associations were highly biological plausible, including associations within GABA transporter 1, SLC6A1 (solute carrier family 6, member 1), and exonic hits in LOC100129340 (mitofusin-1-like). Pathway analyses elaborated single marker results, indicating significant enriched associations to intuitive biological mechanisms, including neurotransmission, xenobiotic pharmacodynamics, and nuclear hormone receptors (NHR). These findings underscore the value of combining longitudinal behavioral data and genome-wide genotype information in order to study developmental patterns and improve statistical power in genomic studies.

  12. Anxiety genetics – findings from cross-species genome-wide approaches

    PubMed Central

    2013-01-01

    Anxiety disorders are complex diseases, which often occur in combination with major depression, alcohol use disorder, or general medical conditions. Anxiety disorders were the most common mental disorders within the EU states in 2010 with 14% prevalence. Anxiety disorders are triggered by environmental factors in genetically susceptible individuals, and therefore genetic research offers a great route to unravel molecular basis of these diseases. As anxiety is an evolutionarily conserved response, mouse models can be used to carry out genome-wide searches for specific genes in a setting that controls for the environmental factors. In this review, we discuss translational approaches that aim to bridge results from unbiased genome-wide screens using mouse models to anxiety disorders in humans. Several methods, such as quantitative trait locus mapping, gene expression profiling, and proteomics, have been used in various mouse models of anxiety to identify genes that regulate anxiety or play a role in maintaining pathological anxiety. We first discuss briefly the evolutionary background of anxiety, which justifies cross-species approaches. We then describe how several genes have been identified through genome-wide methods in mouse models and subsequently investigated in human anxiety disorder samples as candidate genes. These studies have led to the identification of completely novel biological pathways that regulate anxiety in mice and humans, and that can be further investigated as targets for therapy. PMID:23659354

  13. High-Resolution Genetic Map for Understanding the Effect of Genome-Wide Recombination Rate on Nucleotide Diversity in Watermelon

    PubMed Central

    Reddy, Umesh K.; Nimmakayala, Padma; Levi, Amnon; Abburi, Venkata Lakshmi; Saminathan, Thangasamy; Tomason, Yan. R.; Vajja, Gopinath; Reddy, Rishi; Abburi, Lavanya; Wehner, Todd C.; Ronin, Yefim; Karol, Abraham

    2014-01-01

    We used genotyping by sequencing to identify a set of 10,480 single nucleotide polymorphism (SNP) markers for constructing a high-resolution genetic map of 1096 cM for watermelon. We assessed the genome-wide variation in recombination rate (GWRR) across the map and found an association between GWRR and genome-wide nucleotide diversity. Collinearity between the map and the genome-wide reference sequence for watermelon was studied to identify inconsistency and chromosome rearrangements. We assessed genome-wide nucleotide diversity, linkage disequilibrium (LD), and selective sweep for wild, semi-wild, and domesticated accessions of Citrullus lanatus var. lanatus to track signals of domestication. Principal component analysis combined with chromosome-wide phylogenetic study based on 1563 SNPs obtained after LD pruning with minor allele frequency of 0.05 resolved the differences between semi-wild and wild accessions as well as relationships among worldwide sweet watermelon. Population structure analysis revealed predominant ancestries for wild, semi-wild, and domesticated watermelons as well as admixture of various ancestries that were important for domestication. Sliding window analysis of Tajima’s D across various chromosomes was used to resolve selective sweep. LD decay was estimated for various chromosomes. We identified a strong selective sweep on chromosome 3 consisting of important genes that might have had a role in sweet watermelon domestication. PMID:25227227

  14. Genome-wide view of genetic diversity reveals paths of selection and cultivar differentiation in peach domestication

    PubMed Central

    Akagi, Takashi; Hanada, Toshio; Yaegaki, Hideaki; Gradziel, Thomas M.; Tao, Ryutaro

    2016-01-01

    Domestication and cultivar differentiation are requisite processes for establishing cultivated crops. These processes inherently involve substantial changes in population structure, including those from artificial selection of key genes. In this study, accessions of peach (Prunus persica) and its wild relatives were analysed genome-wide to identify changes in genetic structures and gene selections associated with their differentiation. Analysis of genome-wide informative single-nucleotide polymorphism loci revealed distinct changes in genetic structures and delineations among domesticated peach and its wild relatives and among peach landraces and modern fruit (F) and modern ornamental (O-A) cultivars. Indications of distinct changes in linkage disequilibrium extension/decay and of strong population bottlenecks or inbreeding were identified. Site frequency spectrum- and extended haplotype homozygosity-based evaluation of genome-wide genetic diversities supported selective sweeps distinguishing the domesticated peach from its wild relatives and each F/O-A cluster from the landrace clusters. The regions with strong selective sweeps harboured promising candidates for genes subjected to selection. Further sequence-based evaluation further defined the candidates and revealed their characteristics. All results suggest opportunities for identifying critical genes associated with each differentiation by analysing genome-wide genetic diversity in currently established populations. This approach obviates the special development of genetic populations, which is particularly difficult for long-lived tree crops. PMID:27085183

  15. Genome-wide view of genetic diversity reveals paths of selection and cultivar differentiation in peach domestication.

    PubMed

    Akagi, Takashi; Hanada, Toshio; Yaegaki, Hideaki; Gradziel, Thomas M; Tao, Ryutaro

    2016-06-01

    Domestication and cultivar differentiation are requisite processes for establishing cultivated crops. These processes inherently involve substantial changes in population structure, including those from artificial selection of key genes. In this study, accessions of peach (Prunus persica) and its wild relatives were analysed genome-wide to identify changes in genetic structures and gene selections associated with their differentiation. Analysis of genome-wide informative single-nucleotide polymorphism loci revealed distinct changes in genetic structures and delineations among domesticated peach and its wild relatives and among peach landraces and modern fruit (F) and modern ornamental (O-A) cultivars. Indications of distinct changes in linkage disequilibrium extension/decay and of strong population bottlenecks or inbreeding were identified. Site frequency spectrum- and extended haplotype homozygosity-based evaluation of genome-wide genetic diversities supported selective sweeps distinguishing the domesticated peach from its wild relatives and each F/O-A cluster from the landrace clusters. The regions with strong selective sweeps harboured promising candidates for genes subjected to selection. Further sequence-based evaluation further defined the candidates and revealed their characteristics. All results suggest opportunities for identifying critical genes associated with each differentiation by analysing genome-wide genetic diversity in currently established populations. This approach obviates the special development of genetic populations, which is particularly difficult for long-lived tree crops.

  16. Genome-wide evidence for speciation with gene flow in Heliconius butterflies

    PubMed Central

    Martin, Simon H.; Dasmahapatra, Kanchon K.; Nadeau, Nicola J.; Salazar, Camilo; Walters, James R.; Simpson, Fraser; Blaxter, Mark; Manica, Andrea; Mallet, James; Jiggins, Chris D.

    2013-01-01

    Most speciation events probably occur gradually, without complete and immediate reproductive isolation, but the full extent of gene flow between diverging species has rarely been characterized on a genome-wide scale. Documenting the extent and timing of admixture between diverging species can clarify the role of geographic isolation in speciation. Here we use new methodology to quantify admixture at different stages of divergence in Heliconius butterflies, based on whole-genome sequences of 31 individuals. Comparisons between sympatric and allopatric populations of H. melpomene, H. cydno, and H. timareta revealed a genome-wide trend of increased shared variation in sympatry, indicative of pervasive interspecific gene flow. Up to 40% of 100-kb genomic windows clustered by geography rather than by species, demonstrating that a very substantial fraction of the genome has been shared between sympatric species. Analyses of genetic variation shared over different time intervals suggested that admixture between these species has continued since early in speciation. Alleles shared between species during recent time intervals displayed higher levels of linkage disequilibrium than those shared over longer time intervals, suggesting that this admixture took place at multiple points during divergence and is probably ongoing. The signal of admixture was significantly reduced around loci controlling divergent wing patterns, as well as throughout the Z chromosome, consistent with strong selection for Müllerian mimicry and with known Z-linked hybrid incompatibility. Overall these results show that species divergence can occur in the face of persistent and genome-wide admixture over long periods of time. PMID:24045163

  17. Power comparison of admixture mapping and direct association analysis in genome-wide association studies.

    PubMed

    Qin, Huaizhen; Zhu, Xiaofeng

    2012-04-01

    When dense markers are available, one can interrogate almost every common variant across the genome via imputation and single nucleotide polymorphism (SNP) test, which has become a routine in current genome-wide association studies (GWASs). As a complement, admixture mapping exploits the long-range linkage disequilibrium (LD) generated by admixture between genetically distinct ancestral populations. It is then questionable whether admixture mapping analysis is still necessary in detecting the disease associated variants in admixed populations. We argue that admixture mapping is able to reduce the burden of massive comparisons in GWASs; it therefore can be a powerful tool to locate the disease variants with substantial allele frequency differences between ancestral populations. In this report we studied a two-stage approach, where candidate regions are defined by conducting admixture mapping at stage 1, and single SNP association tests are followed at stage 2 within the candidate regions defined at stage 1. We first established the genome-wide significance levels corresponding to the criteria to define the candidate regions at stage 1 by simulations. We next compared the power of the two-stage approach with direct association analysis. Our simulations suggest that the two-stage approach can be more powerful than the standard genome-wide association analysis when the allele frequency difference of a causal variant in ancestral populations, is larger than 0.4. Our conclusion is consistent with a theoretical prediction by Risch and Tang ([2006] Am J Hum Genet 79:S254). Surprisingly, our study also suggests that power can be improved when we use less strict criteria to define the candidate regions at stage 1.

  18. Genome-Wide Significant Association between Alcohol Dependence and a Variant in the ADH Gene Cluster

    PubMed Central

    Frank, Josef; Cichon, Sven; Treutlein, Jens; Ridinger, Monika; Mattheisen, Manuel; Hoffmann, Per; Herms, Stefan; Wodarz, Norbert; Soyka, Michael; Zill, Peter; Maier, Wolfgang; Mössner, Rainald; Gaebel, Wolfgang; Dahmen, Norbert; Scherbaum, Norbert; Schmäl, Christine; Steffens, Michael; Lucae, Susanne; Ising, Marcus; Müller-Myhsok, Bertram; Nöthen, Markus M; Mann, Karl; Kiefer, Falk; Rietschel, Marcella

    2011-01-01

    Alcohol dependence (AD) is an important contributory factor to the global burden of disease. The etiology of AD involves both environmental and genetic factors, and the disorder has a heritability of around 50%. The aim of the present study was to identify susceptibility genes for AD by performing a genome-wide association study (GWAS). The sample comprised 1,333 male in-patients with severe DSM-IV AD and 2,168 controls. These included 487 patients and 1,358 controls from a previous GWAS study by our group. All individuals were of German descent. Single marker tests and a polygenic score based analysis to assess the combined contribution of multiple markers with small effects were performed. The SNP rs1789891, which is located between the ADH1B and ADH1C genes, achieved genome-wide significance (p=1.27E–8; OR=1.46). Other markers from this region were also associated with AD, and conditional analyses indicated that these made a partially independent contribution. The SNP rs1789891 is in complete linkage disequilibrium with the functional Arg272Gln variant (p=1.24E–7, OR=1.31) of the ADH1C gene, which has been reported to modify the rate of ethanol oxidation to acetaldehyde in vitro. A polygenic score based approach produced a significant result (p=9.66E–9). This is the first GWAS of AD to provide genome-wide significant support for the role of the ADH gene cluster and to suggest a polygenic component to the etiology of AD. The latter result suggests that many more AD susceptibility genes still await identification. PMID:22004471

  19. Genome-wide patterns of selection in 230 ancient Eurasians.

    PubMed

    Mathieson, Iain; Lazaridis, Iosif; Rohland, Nadin; Mallick, Swapan; Patterson, Nick; Roodenberg, Songül Alpaslan; Harney, Eadaoin; Stewardson, Kristin; Fernandes, Daniel; Novak, Mario; Sirak, Kendra; Gamba, Cristina; Jones, Eppie R; Llamas, Bastien; Dryomov, Stanislav; Pickrell, Joseph; Arsuaga, Juan Luís; de Castro, José María Bermúdez; Carbonell, Eudald; Gerritsen, Fokke; Khokhlov, Aleksandr; Kuznetsov, Pavel; Lozano, Marina; Meller, Harald; Mochalov, Oleg; Moiseyev, Vyacheslav; Guerra, Manuel A Rojo; Roodenberg, Jacob; Vergès, Josep Maria; Krause, Johannes; Cooper, Alan; Alt, Kurt W; Brown, Dorcas; Anthony, David; Lalueza-Fox, Carles; Haak, Wolfgang; Pinhasi, Ron; Reich, David

    2015-12-24

    Ancient DNA makes it possible to observe natural selection directly by analysing samples from populations before, during and after adaptation events. Here we report a genome-wide scan for selection using ancient DNA, capitalizing on the largest ancient DNA data set yet assembled: 230 West Eurasians who lived between 6500 and 300 bc, including 163 with newly reported data. The new samples include, to our knowledge, the first genome-wide ancient DNA from Anatolian Neolithic farmers, whose genetic material we obtained by extracting from petrous bones, and who we show were members of the population that was the source of Europe's first farmers. We also report a transect of the steppe region in Samara between 5600 and 300 bc, which allows us to identify admixture into the steppe from at least two external sources. We detect selection at loci associated with diet, pigmentation and immunity, and two independent episodes of selection on height.

  20. Genome-wide patterns of selection in 230 ancient Eurasians

    PubMed Central

    Mathieson, Iain; Lazaridis, Iosif; Rohland, Nadin; Mallick, Swapan; Patterson, Nick; Roodenberg, Songül Alpaslan; Harney, Eadaoin; Stewardson, Kristin; Fernandes, Daniel; Novak, Mario; Sirak, Kendra; Gamba, Cristina; Jones, Eppie R.; Llamas, Bastien; Dryomov, Stanislav; Pickrel, Joseph; Arsuaga, Juan Luís; de Castro, José María Bermúdez; Carbonell, Eudald; Gerritsen, Fokke; Khokhlov, Aleksandr; Kuznetsov, Pavel; Lozano, Marina; Meller, Harald; Mochalov, Oleg; Moiseyev, Vayacheslav; Rojo Guerra, Manuel A.; Roodenberg, Jacob; Vergès, Josep Maria; Krause, Johannes; Cooper, Alan; Alt, Kurt W.; Brown, Dorcas; Anthony, David; Lalueza-Fox, Carles; Haak, Wolfgang; Pinhasi, Ron; Reich, David

    2016-01-01

    Ancient DNA makes it possible to directly witness natural selection by analyzing samples from populations before, during and after adaptation events. Here we report the first scan for selection using ancient DNA, capitalizing on the largest genome-wide dataset yet assembled: 230 West Eurasians dating to between 6500 and 1000 BCE, including 163 with newly reported data. The new samples include the first genome-wide data from the Anatolian Neolithic culture whose genetic material we extracted from the DNA-rich petrous bone and who we show were members of the population that was the source of Europe’s first farmers. We also report a complete transect of the steppe region in Samara between 5500 and 1200 BCE that allows us to recognize admixture from at least two external sources into steppe populations during this period. We detect selection at loci associated with diet, pigmentation and immunity, and two independent episodes of selection on height. PMID:26595274

  1. Genome-wide association studies of obesity and metabolic syndrome.

    PubMed

    Fall, Tove; Ingelsson, Erik

    2014-01-25

    Until just a few years ago, the genetic determinants of obesity and metabolic syndrome were largely unknown, with the exception of a few forms of monogenic extreme obesity. Since genome-wide association studies (GWAS) became available, large advances have been made. The first single nucleotide polymorphism robustly associated with increased body mass index (BMI) was in 2007 mapped to a gene with for the time unknown function. This gene, now known as fat mass and obesity associated (FTO) has been repeatedly replicated in several ethnicities and is affecting obesity by regulating appetite. Since the first report from a GWAS of obesity, an increasing number of markers have been shown to be associated with BMI, other measures of obesity or fat distribution and metabolic syndrome. This systematic review of obesity GWAS will summarize genome-wide significant findings for obesity and metabolic syndrome and briefly give a few suggestions of what is to be expected in the next few years.

  2. Genome wide copy number analysis of single cells

    PubMed Central

    Baslan, Timour; Kendall, Jude; Rodgers, Linda; Cox, Hilary; Riggs, Mike; Stepansky, Asya; Troge, Jennifer; Ravi, Kandasamy; Esposito, Diane; Lakshmi, B.; Wigler, Michael; Navin, Nicholas; Hicks, James

    2016-01-01

    Summary Copy number variation (CNV) is increasingly recognized as an important contributor to phenotypic variation in health and disease. Most methods for determining CNV rely on admixtures of cells, where information regarding genetic heterogeneity is lost. Here, we present a protocol that allows for the genome wide copy number analysis of single nuclei isolated from mixed populations of cells. Single nucleus sequencing (SNS), combines flow sorting of single nuclei based on DNA content, whole genome amplification (WGA), followed by next generation sequencing to quantize genomic intervals in a genome wide manner. Multiplexing of single cells is discussed. Additionally, we outline informatic approaches that correct for biases inherent in the WGA procedure and allow for accurate determination of copy number profiles. All together, the protocol takes ~3 days from flow cytometry to sequence-ready DNA libraries. PMID:22555242

  3. Genome-wide functional analysis in Candida albicans.

    PubMed

    Motaung, Thabiso E; Ells, Ruan; Pohl, Carolina H; Albertyn, Jacobus; Tsilo, Toi J

    2017-02-08

    Candida albicans is an important etiological agent of superficial and life-threatening infections in individuals with compromised immune systems. To date, we know of several overlapping genetic networks that govern virulence attributes in this fungal pathogen. Classical use of deletion mutants has led to the discovery of numerous virulence factors over the years, and genome-wide functional analysis has propelled gene discovery at an even faster pace. Indeed, a number of recent studies using large-scale genetic screens followed by genome-wide functional analysis has allowed for the unbiased discovery of many new genes involved in C. albicans biology. Here we share our perspectives on the role of these studies in analyzing fundamental aspects of C. albicans virulence properties.

  4. Analysis of Heritability Using Genome-Wide Data.

    PubMed

    Hall, Jacob B; Bush, William S

    2016-10-11

    Most analyses of genome-wide association data consider each variant independently without considering or adjusting for the genetic background present in the rest of the genome. New approaches to genome analysis use representations of genomic sharing to better account for confounding factors like population stratification or to directly approximate heritability through the estimated sharing of individuals in a dataset. These approaches use mixed linear models, which relate genotypic sharing to phenotypic sharing, and rely on the efficient computation of genetic sharing among individuals in a dataset. This unit describes the principles and practical application of mixed models for the analysis of genome-wide association study data. © 2016 by John Wiley & Sons, Inc.

  5. Genome-Wide Significant Loci: How Important Are They?

    PubMed Central

    Björkegren, Johan L.M.; Kovacic, Jason C.; Dudley, Joel T.; Schadt, Eric E.

    2015-01-01

    Genome-wide association studies (GWAS) have been extensively used to study common complex diseases such as coronary artery disease (CAD), revealing 153 suggestive CAD loci, of which at least 46 have been validated as having genome-wide significance. However, these loci collectively explain <10% of the genetic variance in CAD. Thus, we must address the key question of what factors constitute the remaining 90% of CAD heritability. We review possible limitations of GWAS, and contextually consider some candidate CAD loci identified by this method. Looking ahead, we propose systems genetics as a complementary approach to unlocking the CAD heritability and etiology. Systems genetics builds network models of relevant molecular processes by combining genetic and genomic datasets to ultimately identify key “drivers” of disease. By leveraging systems-based genetic approaches, we can help reveal the full genetic basis of common complex disorders, enabling novel diagnostic and therapeutic opportunities. PMID:25720628

  6. Genome-Wide Association Studies and Liver Disease

    PubMed Central

    Speliotes, Elizabeth K.

    2016-01-01

    Sequencing of the human genome has opened up many opportunities to learn about our own genetic susceptibilities to disease. In this Foreword to this issue of Seminars in Liver Disease, I provide some required background to understanding genome-wide association analyses in general, including a list of terms (Table 1) often used in such studies. Five areas of particular significance are then reviewed in detail in the articles that follow. PMID:26676811

  7. Genome-wide association study of schizophrenia in Ashkenazi Jews.

    PubMed

    Goes, Fernando S; McGrath, John; Avramopoulos, Dimitrios; Wolyniec, Paula; Pirooznia, Mehdi; Ruczinski, Ingo; Nestadt, Gerald; Kenny, Eimear E; Vacic, Vladimir; Peters, Inga; Lencz, Todd; Darvasi, Ariel; Mulle, Jennifer G; Warren, Stephen T; Pulver, Ann E

    2015-12-01

    Schizophrenia is a common, clinically heterogeneous disorder associated with lifelong morbidity and early mortality. Several genetic variants associated with schizophrenia have been identified, but the majority of the heritability remains unknown. In this study, we report on a case-control sample of Ashkenazi Jews (AJ), a founder population that may provide additional insights into genetic etiology of schizophrenia. We performed a genome-wide association analysis (GWAS) of 592 cases and 505 controls of AJ ancestry ascertained in the US. Subsequently, we performed a meta-analysis with an Israeli AJ sample of 913 cases and 1640 controls, followed by a meta-analysis and polygenic risk scoring using summary results from Psychiatric GWAS Consortium 2 schizophrenia study. The U.S. AJ sample showed strong evidence of polygenic inheritance (pseudo-R(2) ∼9.7%) and a SNP-heritability estimate of 0.39 (P = 0.00046). We found no genome-wide significant associations in the U.S. sample or in the combined US/Israeli AJ meta-analysis of 1505 cases and 2145 controls. The strongest AJ specific associations (P-values in 10(-6) -10(-7) range) were in the 22q 11.2 deletion region and included the genes TBX1, GLN1, and COMT. Supportive evidence (meta P < 1 × 10(-4) ) was also found for several previously identified genome-wide significant findings, including the HLA region, CNTN4, IMMP2L, and GRIN2A. The meta-analysis of the U.S. sample with the PGC2 results provided initial genome-wide significant evidence for six new loci. Among the novel potential susceptibility genes is PEPD, a gene involved in proline metabolism, which is associated with a Mendelian disorder characterized by developmental delay and cognitive deficits. © 2015 Wiley Periodicals, Inc.

  8. Genome-Wide Profiling of Alternative Translation Initiation Sites.

    PubMed

    Gao, Xiangwei; Wan, Ji; Qian, Shu-Bing

    2016-01-01

    Regulation of translation initiation is a central control point in protein synthesis. Variations of start codon selection contribute to protein diversity and complexity. Systemic mapping of start codon positions and precise measurement of the corresponding initiation rate would transform our understanding of translational control. Here we describe a ribosome profiling approach that enables identification of translation initiation sites on a genome-wide scale. By capturing initiating ribosomes using lactimidomycin, this approach permits qualitative and quantitative analysis of alternative translation initiation.

  9. Genome-wide association study of paliperidone efficacy

    PubMed Central

    Wineinger, Nathan E.; Fu, Dong-Jing; Libiger, Ondrej; Alphs, Larry; Savitz, Adam; Gopal, Srihari; Cohen, Nadine; Schork, Nicholas J.

    2017-01-01

    Objective Clinical response to the atypical antipsychotic paliperidone is known to vary among schizophrenic patients. We carried out a genome-wide association study to identify common genetic variants predictive of paliperidone efficacy. Methods We leveraged a collection of 1390 samples from individuals of European ancestry enrolled in 12 clinical studies investigating the efficacy of the extended-release tablet paliperidone ER (n1=490) and the once-monthly injection paliperidone palmitate (n2=550 and n3=350). We carried out a genome-wide association study using a general linear model (GLM) analysis on three separate cohorts, followed by meta-analysis and using a mixed linear model analysis on all samples. The variations in response explained by each single nucleotide polymorphism (h2SNP) were estimated. Results No SNP passed genome-wide significance in the GLM-based analyses with suggestive signals from rs56240334 [P=7.97×10−8 for change in the Clinical Global Impression Scale-Severity (CGI-S); P=8.72×10−7 for change in the total Positive and Negative Syndrome Scale (PANSS)] in the intron of ADCK1. The mixed linear model-based association P-values for rs56240334 were consistent with the results from GLM-based analyses and the association with change in CGI-S (P=4.26×10−8) reached genome-wide significance (i.e. P<5×10−8). We also found suggestive evidence for a polygenic contribution toward paliperidone treatment response with estimates of heritability, h2SNP, ranging from 0.31 to 0.43 for change in the total PANSS score, the PANSS positive Marder factor score, and CGI-S. Conclusion Genetic variations in the ADCK1 gene may differentially predict paliperidone efficacy in schizophrenic patients. However, this finding should be replicated in additional samples. PMID:27846195

  10. Genome-wide epigenomic profiling for biomarker discovery.

    PubMed

    Dirks, René A M; Stunnenberg, Hendrik G; Marks, Hendrik

    2016-01-01

    A myriad of diseases is caused or characterized by alteration of epigenetic patterns, including changes in DNA methylation, post-translational histone modifications, or chromatin structure. These changes of the epigenome represent a highly interesting layer of information for disease stratification and for personalized medicine. Traditionally, epigenomic profiling required large amounts of cells, which are rarely available with clinical samples. Also, the cellular heterogeneity complicates analysis when profiling clinical samples for unbiased genome-wide biomarker discovery. Recent years saw great progress in miniaturization of genome-wide epigenomic profiling, enabling large-scale epigenetic biomarker screens for disease diagnosis, prognosis, and stratification on patient-derived samples. All main genome-wide profiling technologies have now been scaled down and/or are compatible with single-cell readout, including: (i) Bisulfite sequencing to determine DNA methylation at base-pair resolution, (ii) ChIP-Seq to identify protein binding sites on the genome, (iii) DNaseI-Seq/ATAC-Seq to profile open chromatin, and (iv) 4C-Seq and HiC-Seq to determine the spatial organization of chromosomes. In this review we provide an overview of current genome-wide epigenomic profiling technologies and main technological advances that allowed miniaturization of these assays down to single-cell level. For each of these technologies we evaluate their application for future biomarker discovery. We will focus on (i) compatibility of these technologies with methods used for clinical sample preservation, including methods used by biobanks that store large numbers of patient samples, and (ii) automation of these technologies for robust sample preparation and increased throughput.

  11. Significance of genome-wide association studies in molecular anthropology.

    PubMed

    Gupta, Vipin; Khadgawat, Rajesh; Sachdeva, Mohinder Pal

    2009-12-01

    The successful advent of a genome-wide approach in association studies raises the hopes of human geneticists for solving a genetic maze of complex traits especially the disorders. This approach, which is replete with the application of cutting-edge technology and supported by big science projects (like Human Genome Project; and even more importantly the International HapMap Project) and various important databases (SNP database, CNV database, etc.), has had unprecedented success in rapidly uncovering many of the genetic determinants of complex disorders. The magnitude of this approach in the genetics of classical anthropological variables like height, skin color, eye color, and other genome diversity projects has certainly expanded the horizons of molecular anthropology. Therefore, in this article we have proposed a genome-wide association approach in molecular anthropological studies by providing lessons from the exemplary study of the Wellcome Trust Case Control Consortium. We have also highlighted the importance and uniqueness of Indian population groups in facilitating the design and finding optimum solutions for other genome-wide association-related challenges.

  12. Voxelwise genome-wide association study (vGWAS).

    PubMed

    Stein, Jason L; Hua, Xue; Lee, Suh; Ho, April J; Leow, Alex D; Toga, Arthur W; Saykin, Andrew J; Shen, Li; Foroud, Tatiana; Pankratz, Nathan; Huentelman, Matthew J; Craig, David W; Gerber, Jill D; Allen, April N; Corneveaux, Jason J; Dechairo, Bryan M; Potkin, Steven G; Weiner, Michael W; Thompson, Paul

    2010-11-15

    The structure of the human brain is highly heritable, and is thought to be influenced by many common genetic variants, many of which are currently unknown. Recent advances in neuroimaging and genetics have allowed collection of both highly detailed structural brain scans and genome-wide genotype information. This wealth of information presents a new opportunity to find the genes influencing brain structure. Here we explore the relation between 448,293 single nucleotide polymorphisms in each of 31,622 voxels of the entire brain across 740 elderly subjects (mean age+/-s.d.: 75.52+/-6.82 years; 438 male) including subjects with Alzheimer's disease, Mild Cognitive Impairment, and healthy elderly controls from the Alzheimer's Disease Neuroimaging Initiative (ADNI). We used tensor-based morphometry to measure individual differences in brain structure at the voxel level relative to a study-specific template based on healthy elderly subjects. We then conducted a genome-wide association at each voxel to identify genetic variants of interest. By studying only the most associated variant at each voxel, we developed a novel method to address the multiple comparisons problem and computational burden associated with the unprecedented amount of data. No variant survived the strict significance criterion, but several genes worthy of further exploration were identified, including CSMD2 and CADPS2. These genes have high relevance to brain structure. This is the first voxelwise genome wide association study to our knowledge, and offers a novel method to discover genetic influences on brain structure.

  13. Genome-wide DNA polymorphism analyses using VariScan

    PubMed Central

    Hutter, Stephan; Vilella, Albert J; Rozas, Julio

    2006-01-01

    Background DNA sequence polymorphisms analysis can provide valuable information on the evolutionary forces shaping nucleotide variation, and provides an insight into the functional significance of genomic regions. The recent ongoing genome projects will radically improve our capabilities to detect specific genomic regions shaped by natural selection. Current available methods and software, however, are unsatisfactory for such genome-wide analysis. Results We have developed methods for the analysis of DNA sequence polymorphisms at the genome-wide scale. These methods, which have been tested on a coalescent-simulated and actual data files from mouse and human, have been implemented in the VariScan software package version 2.0. Additionally, we have also incorporated a graphical-user interface. The main features of this software are: i) exhaustive population-genetic analyses including those based on the coalescent theory; ii) analysis adapted to the shallow data generated by the high-throughput genome projects; iii) use of genome annotations to conduct a comprehensive analyses separately for different functional regions; iv) identification of relevant genomic regions by the sliding-window and wavelet-multiresolution approaches; v) visualization of the results integrated with current genome annotations in commonly available genome browsers. Conclusion VariScan is a powerful and flexible suite of software for the analysis of DNA polymorphisms. The current version implements new algorithms, methods, and capabilities, providing an important tool for an exhaustive exploratory analysis of genome-wide DNA polymorphism data. PMID:16968531

  14. Genome-Wide Detection and Analysis of Multifunctional Genes

    PubMed Central

    Pritykin, Yuri; Ghersi, Dario; Singh, Mona

    2015-01-01

    Many genes can play a role in multiple biological processes or molecular functions. Identifying multifunctional genes at the genome-wide level and studying their properties can shed light upon the complexity of molecular events that underpin cellular functioning, thereby leading to a better understanding of the functional landscape of the cell. However, to date, genome-wide analysis of multifunctional genes (and the proteins they encode) has been limited. Here we introduce a computational approach that uses known functional annotations to extract genes playing a role in at least two distinct biological processes. We leverage functional genomics data sets for three organisms—H. sapiens, D. melanogaster, and S. cerevisiae—and show that, as compared to other annotated genes, genes involved in multiple biological processes possess distinct physicochemical properties, are more broadly expressed, tend to be more central in protein interaction networks, tend to be more evolutionarily conserved, and are more likely to be essential. We also find that multifunctional genes are significantly more likely to be involved in human disorders. These same features also hold when multifunctionality is defined with respect to molecular functions instead of biological processes. Our analysis uncovers key features about multifunctional genes, and is a step towards a better genome-wide understanding of gene multifunctionality. PMID:26436655

  15. Genome-Wide Association Study of Polymorphisms Predisposing to Bronchiolitis

    PubMed Central

    Pasanen, Anu; Karjalainen, Minna K.; Bont, Louis; Piippo-Savolainen, Eija; Ruotsalainen, Marja; Goksör, Emma; Kumawat, Kuldeep; Hodemaekers, Hennie; Nuolivirta, Kirsi; Jartti, Tuomas; Wennergren, Göran; Hallman, Mikko; Rämet, Mika; Korppi, Matti

    2017-01-01

    Bronchiolitis is a major cause of hospitalization among infants. Severe bronchiolitis is associated with later asthma, suggesting a common genetic predisposition. Genetic background of bronchiolitis is not well characterized. To identify polymorphisms associated with bronchiolitis, we conducted a genome-wide association study (GWAS) in which 5,300,000 single nucleotide polymorphisms (SNPs) were tested for association in a Finnish–Swedish population of 217 children hospitalized for bronchiolitis and 778 controls. The most promising SNPs (n = 77) were genotyped in a Dutch replication population of 416 cases and 432 controls. Finally, we used a set of 202 Finnish bronchiolitis cases to further investigate candidate SNPs. We did not detect genome-wide significant associations, but several suggestive association signals (p < 10−5) were observed in the GWAS. In the replication population, three SNPs were nominally associated (p < 0.05). Of them, rs269094 was an expression quantitative trait locus (eQTL) for KCND3, previously shown to be associated with occupational asthma. In the additional set of Finnish cases, the association for another SNP (rs9591920) within a noncoding RNA locus was further strengthened. Our results provide a first genome-wide examination of the genetics underlying bronchiolitis. These preliminary findings require further validation in a larger sample size. PMID:28139761

  16. Genome-Wide Estimates of Heritability for Social Demographic Outcomes

    PubMed Central

    Domingue, Benjamin W.; Wedow, Robbee; Conley, Dalton; McQueen, Matt; Hoffmann, Thomas J.; Boardman, Jason D.

    2016-01-01

    An increasing number of studies that are widely used in the demographic research community have collected genome-wide data from their respondents. It is therefore important that demographers have a proper understanding of some of the methodological tools needed to analyze such data. Our paper details the underlying methodology behind one of the most common techniques for analyzing genome-wide data, Genome-Wide Complex Trait Analysis (GCTA). GCTA models provide heritability estimates for health, health behaviors, or indicators of attainment using data from unrelated persons.. Our goal is to describe this model, to highlight the utility of the model for biodemographic research, and to demonstrate the performance of this approach under modifications of the underlying assumptions. The first set of modifications involves changing the nature of the genetic data used to compute genetic similarities between individuals (the genetic relationship matrix). We then explore the sensitivity of the model to heteroscedastic errors. In general, GCTA estimates are robust to the modifications proposed here but we also highlight potential limitations of GCTA estimates. PMID:27050030

  17. Genome-wide association study identifies candidate markers for bull fertility in Holstein dairy cattle.

    PubMed

    Peñagaricano, F; Weigel, K A; Khatib, H

    2012-07-01

    The decline in the reproductive efficiency of dairy cattle has become a challenging problem worldwide. Female fertility is now taken into account in breeding goals while generally less attention is given to male fertility. The objective of this study was to perform a genome-wide association study in Holstein bulls to identify genetic variants significantly related to sire conception rate (SCR), a new phenotypic evaluation of bull fertility. The analysis included 1755 sires with SCR data and 38,650 single nucleotide polymorphisms (SNPs) spanning the entire bovine genome. Associations between SNPs and SCR were analyzed using a mixed linear model that included a random polygenic effect and SNP genotype either as a linear covariate or as a categorical variable. A multiple testing correction approach was used to account for the correlation between SNPs because of linkage disequilibrium. After genome-wide correction, eight SNPs showed significant association with SCR. Some of these SNPs are located close to or in the middle of genes with functions related to male fertility, such as the sperm acrosome reaction, chromatin remodeling during the spermatogenesis, and the meiotic process during male germ cell maturation. Some SNPs showed marked dominance effects, which provide more evidence for the relevance of non-additive effects in traits closely related to fitness such as fertility. The results could contribute to the identification of genes and pathways associated with male fertility in dairy cattle.

  18. A Rapid Genome-wide Gene-based Association Test with Multivariate Traits

    PubMed Central

    Basu, Saonli; Zhang, Yiwei; Ray, Debashree; Miller, Michael B.; Iacono, William G.; McGueM, Matt

    2013-01-01

    Objectives: A gene-based genome-wide association study (GWAS) provides a powerful alternative to the traditional single SNP association analysis due to its substantial reduction in the multiple testing burden and possible gain in power due to modeling multiple SNPs within a gene. A gene-based association analysis on multivariate traits is often of interest, but imposes substantial analytical as well as computational challenges to implement it at a genome-wide level. Methods: We have proposed a rapid implementation of multivariate multiple linear regression approach (RMMLR) in unrelated individuals as well as in families. Our approach allows for covariates. Moreover the asymptotic distribution of the test statistic is not heavily influenced by the linkage disequilibrium (LD) among the SNPs and hence can be used efficiently to perform a gene-based GWAS. We have developed corresponding R package to implement such multivariate gene-based GWAS with this RMMLR approach. Results: We compare through extensive simulation several approaches for both single and multivariate traits. Our RMMLR maintains correct type-I error level even for set of SNPs in strong LD. It also has substantial gain in power to detect a gene when it is associated with a subset of the traits. We have also studied their performance on Minnesota Center for Twin Family Research dataset. Conclusions: In our overall comparison, our RMMLR approach provides an efficient and powerful tool to perform a gene-based GWAS with single or multivariate traits and maintains the type I error appropriately. PMID:24247328

  19. Six decades of vitiligo genetics: genome-wide studies provide insights into autoimmune pathogenesis.

    PubMed

    Spritz, Richard A

    2012-02-01

    Generalized vitiligo (GV) is a complex disease in which patchy depigmentation results from autoimmune loss of melanocytes from affected regions. Genetic analyses of GV span six decades, with the goal of understanding biological mechanisms and elucidating pathways that underlie the disease. The earliest studies attempted to describe the mode of inheritance and genetic epidemiology. Early genetic association studies of biological candidate genes resulted in some successes, principally HLA and PTPN22, but in hindsight many such reports now seem to be false-positives. Later, genome-wide linkage studies of multiplex GV families identified NLRP1 and XBP1, which appear to be valid GV susceptibility genes that control key aspects of immune regulation. Recently, the application of genome-wide association studies to analysis of GV has produced a rich yield of validated GV susceptibility genes that encode components of biological pathways reaching from immune cells to the melanocyte. These genes and pathways provide insights into underlying pathogenetic mechanisms and possible triggers of GV, establish relationships to other autoimmune diseases, and may provide clues to potential new approaches to GV treatment and perhaps even prevention. These results thus validate the hopes and efforts of the early investigators who first attempted to comprehend the genetic basis of vitiligo.

  20. A genome-wide SNP scan accelerates trait-regulatory genomic loci identification in chickpea

    PubMed Central

    Kujur, Alice; Bajaj, Deepak; Upadhyaya, Hari D.; Das, Shouvik; Ranjan, Rajeev; Shree, Tanima; Saxena, Maneesha S.; Badoni, Saurabh; Kumar, Vinod; Tripathi, Shailesh; Gowda, C.L.L.; Sharma, Shivali; Singh, Sube; Tyagi, Akhilesh K.; Parida, Swarup K.

    2015-01-01

    We identified 44844 high-quality SNPs by sequencing 92 diverse chickpea accessions belonging to a seed and pod trait-specific association panel using reference genome- and de novo-based GBS (genotyping-by-sequencing) assays. A GWAS (genome-wide association study) in an association panel of 211, including the 92 sequenced accessions, identified 22 major genomic loci showing significant association (explaining 23–47% phenotypic variation) with pod and seed number/plant and 100-seed weight. Eighteen trait-regulatory major genomic loci underlying 13 robust QTLs were validated and mapped on an intra-specific genetic linkage map by QTL mapping. A combinatorial approach of GWAS, QTL mapping and gene haplotype-specific LD mapping and transcript profiling uncovered one superior haplotype and favourable natural allelic variants in the upstream regulatory region of a CesA-type cellulose synthase (Ca_Kabuli_CesA3) gene regulating high pod and seed number/plant (explaining 47% phenotypic variation) in chickpea. The up-regulation of this superior gene haplotype correlated with increased transcript expression of Ca_Kabuli_CesA3 gene in the pollen and pod of high pod/seed number accession, resulting in higher cellulose accumulation for normal pollen and pollen tube growth. A rapid combinatorial genome-wide SNP genotyping-based approach has potential to dissect complex quantitative agronomic traits and delineate trait-regulatory genomic loci (candidate genes) for genetic enhancement in crop plants, including chickpea. PMID:26058368

  1. Development and application of a novel genome-wide SNP array reveals domestication history in soybean.

    PubMed

    Wang, Jiao; Chu, Shanshan; Zhang, Huairen; Zhu, Ying; Cheng, Hao; Yu, Deyue

    2016-02-09

    Domestication of soybeans occurred under the intense human-directed selections aimed at developing high-yielding lines. Tracing the domestication history and identifying the genes underlying soybean domestication require further exploration. Here, we developed a high-throughput NJAU 355 K SoySNP array and used this array to study the genetic variation patterns in 367 soybean accessions, including 105 wild soybeans and 262 cultivated soybeans. The population genetic analysis suggests that cultivated soybeans have tended to originate from northern and central China, from where they spread to other regions, accompanied with a gradual increase in seed weight. Genome-wide scanning for evidence of artificial selection revealed signs of selective sweeps involving genes controlling domestication-related agronomic traits including seed weight. To further identify genomic regions related to seed weight, a genome-wide association study (GWAS) was conducted across multiple environments in wild and cultivated soybeans. As a result, a strong linkage disequilibrium region on chromosome 20 was found to be significantly correlated with seed weight in cultivated soybeans. Collectively, these findings should provide an important basis for genomic-enabled breeding and advance the study of functional genomics in soybean.

  2. Development and application of a novel genome-wide SNP array reveals domestication history in soybean

    PubMed Central

    Wang, Jiao; Chu, Shanshan; Zhang, Huairen; Zhu, Ying; Cheng, Hao; Yu, Deyue

    2016-01-01

    Domestication of soybeans occurred under the intense human-directed selections aimed at developing high-yielding lines. Tracing the domestication history and identifying the genes underlying soybean domestication require further exploration. Here, we developed a high-throughput NJAU 355 K SoySNP array and used this array to study the genetic variation patterns in 367 soybean accessions, including 105 wild soybeans and 262 cultivated soybeans. The population genetic analysis suggests that cultivated soybeans have tended to originate from northern and central China, from where they spread to other regions, accompanied with a gradual increase in seed weight. Genome-wide scanning for evidence of artificial selection revealed signs of selective sweeps involving genes controlling domestication-related agronomic traits including seed weight. To further identify genomic regions related to seed weight, a genome-wide association study (GWAS) was conducted across multiple environments in wild and cultivated soybeans. As a result, a strong linkage disequilibrium region on chromosome 20 was found to be significantly correlated with seed weight in cultivated soybeans. Collectively, these findings should provide an important basis for genomic-enabled breeding and advance the study of functional genomics in soybean. PMID:26856884

  3. An efficient hierarchical generalized linear mixed model for pathway analysis of genome-wide association studies.

    PubMed

    Wang, Lily; Jia, Peilin; Wolfinger, Russell D; Chen, Xi; Grayson, Britney L; Aune, Thomas M; Zhao, Zhongming

    2011-03-01

    In genome-wide association studies (GWAS) of complex diseases, genetic variants having real but weak associations often fail to be detected at the stringent genome-wide significance level. Pathway analysis, which tests disease association with combined association signals from a group of variants in the same pathway, has become increasingly popular. However, because of the complexities in genetic data and the large sample sizes in typical GWAS, pathway analysis remains to be challenging. We propose a new statistical model for pathway analysis of GWAS. This model includes a fixed effects component that models mean disease association for a group of genes, and a random effects component that models how each gene's association with disease varies about the gene group mean, thus belongs to the class of mixed effects models. The proposed model is computationally efficient and uses only summary statistics. In addition, it corrects for the presence of overlapping genes and linkage disequilibrium (LD). Via simulated and real GWAS data, we showed our model improved power over currently available pathway analysis methods while preserving type I error rate. Furthermore, using the WTCCC Type 1 Diabetes (T1D) dataset, we demonstrated mixed model analysis identified meaningful biological processes that agreed well with previous reports on T1D. Therefore, the proposed methodology provides an efficient statistical modeling framework for systems analysis of GWAS. The software code for mixed models analysis is freely available at http://biostat.mc.vanderbilt.edu/LilyWang.

  4. BlueSNP: R package for highly scalable genome-wide association studies using Hadoop clusters.

    PubMed

    Huang, Hailiang; Tata, Sandeep; Prill, Robert J

    2013-01-01

    Computational workloads for genome-wide association studies (GWAS) are growing in scale and complexity outpacing the capabilities of single-threaded software designed for personal computers. The BlueSNP R package implements GWAS statistical tests in the R programming language and executes the calculations across computer clusters configured with Apache Hadoop, a de facto standard framework for distributed data processing using the MapReduce formalism. BlueSNP makes computationally intensive analyses, such as estimating empirical p-values via data permutation, and searching for expression quantitative trait loci over thousands of genes, feasible for large genotype-phenotype datasets. http://github.com/ibm-bioinformatics/bluesnp

  5. Implications of genome wide association studies for addiction: Are our a priori assumptions all wrong?

    PubMed Central

    Hall, F. Scott; Drgonova, Jana; Jain, Siddharth; Uhl, George R.

    2013-01-01

    Substantial genetic contributions to addiction vulnerability are supported by data from twin studies, linkage studies, candidate gene association studies and, more recently, Genome Wide Association Studies (GWAS). Parallel to this work, animal studies have attempted to identify the genes that may contribute to responses to addictive drugs and addiction liability, initially focusing upon genes for the targets of the major drugs of abuse. These studies identified genes/proteins that affect responses to drugs of abuse; however, this does not necessarily mean that variation in these genes contributes to the genetic component of addiction liability. One of the major problems with initial linkage and candidate gene studies was an a priori focus on the genes thought to be involved in addiction based upon the known contributions of those proteins to drug actions, making the identification of novel genes unlikely. The GWAS approach is systematic and agnostic to such a priori assumptions. From the numerous GWAS now completed several conclusions may be drawn: (1) addiction is highly polygenic; each allelic variant contributing in a small, additive fashion to addiction vulnerability; (2) unexpected, compared to our a priori assumptions, classes of genes are most important in explaining addiction vulnerability; (3) although substantial genetic heterogeneity exists, there is substantial convergence of GWAS signals on particular genes. This review traces the history of this research; from initial transgenic mouse models based upon candidate gene and linkage studies, through the progression of GWAS for addiction and nicotine cessation, to the current human and transgenic mouse studies post-GWAS. PMID:23872493

  6. Implications of genome wide association studies for addiction: are our a priori assumptions all wrong?

    PubMed

    Hall, F Scott; Drgonova, Jana; Jain, Siddharth; Uhl, George R

    2013-12-01

    Substantial genetic contributions to addiction vulnerability are supported by data from twin studies, linkage studies, candidate gene association studies and, more recently, Genome Wide Association Studies (GWAS). Parallel to this work, animal studies have attempted to identify the genes that may contribute to responses to addictive drugs and addiction liability, initially focusing upon genes for the targets of the major drugs of abuse. These studies identified genes/proteins that affect responses to drugs of abuse; however, this does not necessarily mean that variation in these genes contributes to the genetic component of addiction liability. One of the major problems with initial linkage and candidate gene studies was an a priori focus on the genes thought to be involved in addiction based upon the known contributions of those proteins to drug actions, making the identification of novel genes unlikely. The GWAS approach is systematic and agnostic to such a priori assumptions. From the numerous GWAS now completed several conclusions may be drawn: (1) addiction is highly polygenic; each allelic variant contributing in a small, additive fashion to addiction vulnerability; (2) unexpected, compared to our a priori assumptions, classes of genes are most important in explaining addiction vulnerability; (3) although substantial genetic heterogeneity exists, there is substantial convergence of GWAS signals on particular genes. This review traces the history of this research; from initial transgenic mouse models based upon candidate gene and linkage studies, through the progression of GWAS for addiction and nicotine cessation, to the current human and transgenic mouse studies post-GWAS.

  7. Privacy-preserving genome-wide association studies on cloud environment using fully homomorphic encryption.

    PubMed

    Lu, Wen-Jie; Yamada, Yoshiji; Sakuma, Jun

    2015-01-01

    Developed sequencing techniques are yielding large-scale genomic data at low cost. A genome-wide association study (GWAS) targeting genetic variations that are significantly associated with a particular disease offers great potential for medical improvement. However, subjects who volunteer their genomic data expose themselves to the risk of privacy invasion; these privacy concerns prevent efficient genomic data sharing. Our goal is to presents a cryptographic solution to this problem. To maintain the privacy of subjects, we propose encryption of all genotype and phenotype data. To allow the cloud to perform meaningful computation in relation to the encrypted data, we use a fully homomorphic encryption scheme. Noting that we can evaluate typical statistics for GWAS from a frequency table, our solution evaluates frequency tables with encrypted genomic and clinical data as input. We propose to use a packing technique for efficient evaluation of these frequency tables. Our solution supports evaluation of the D' measure of linkage disequilibrium, the Hardy-Weinberg Equilibrium, the χ2 test, etc. In this paper, we take χ2 test and linkage disequilibrium as examples and demonstrate how we can conduct these algorithms securely and efficiently in an outsourcing setting. We demonstrate with experimentation that secure outsourcing computation of one χ2 test with 10, 000 subjects requires about 35 ms and evaluation of one linkage disequilibrium with 10, 000 subjects requires about 80 ms. With appropriate encoding and packing technique, cryptographic solutions based on fully homomorphic encryption for secure computations of GWAS can be practical.

  8. Genome-Wide Association Mapping of Acid Soil Resistance in Barley (Hordeum vulgare L.)

    PubMed Central

    Zhou, Gaofeng; Broughton, Sue; Zhang, Xiao-Qi; Ma, Yanling; Zhou, Meixue; Li, Chengdao

    2016-01-01

    Genome-wide association studies (GWAS) based on linkage disequilibrium (LD) have been used to detect QTLs underlying complex traits in major crops. In this study, we collected 218 barley (Hordeum vulgare L.) lines including wild barley and cultivated barley from China, Canada, Australia, and Europe. A total of 408 polymorphic markers were used for population structure and LD analysis. GWAS for acid soil resistance were performed on the population using a general linkage model (GLM) and a mixed linkage model (MLM), respectively. A total of 22 QTLs (quantitative trait loci) were detected with the GLM and MLM analyses. Two QTLs, close to markers bPb-1959 (133.1 cM) and bPb-8013 (86.7 cM), localized on chromosome 1H and 4H respectively, were consistently detected in two different trials with both the GLM and MLM analyses. Furthermore, bPb-8013, the closest marker to the major Al3+ resistance gene HvAACT1 in barley, was identified to be QTL5. The QTLs could be used in marker-assisted selection to identify and pyramid different loci for improved acid soil resistance in barley. PMID:27064793

  9. Genome-wide association study of 12 agronomic traits in peach.

    PubMed

    Cao, Ke; Zhou, Zhengkui; Wang, Qi; Guo, Jian; Zhao, Pei; Zhu, Gengrui; Fang, Weichao; Chen, Changwen; Wang, Xinwei; Wang, Xiaoli; Tian, Zhixi; Wang, Lirong

    2016-11-08

    Peach (Prunus persica L.) is a highly valuable crop species and is recognized by molecular researchers as a model fruit for the Rosaceae family. Using whole-genome sequencing data generated from 129 peach accessions, here we perform a comprehensive genome-wide association study for 12 key agronomic traits. We show that among the 10 qualitative traits investigated, nine exhibit consistent and more precise association signals than previously identified by linkage analysis. For two of the qualitative traits, we describe candidate genes, one potentially involved in cell death and another predicted to encode an auxin-efflux carrier, that are highly associated with fruit shape and non-acidity, respectively. Furthermore, we find that several genomic regions harbouring association signals for fruit weight and soluble solid content overlapped with predicted selective sweeps that occurred during peach domestication and improvement. Our findings contribute to the large-scale characterization of genes controlling agronomic traits in peach.

  10. The identification of loci for polydactyly in chickens using a genome-wide association study.

    PubMed

    Sheng, Xihui; Chen, Yu; Jia, Yaxiong; Qi, Xiaolong; Feng, Yun; Huang, Zhen; Guo, Yong

    2015-09-01

    Polydactyly is a commonly observed limb malformation in humans and other vertebrates. The Beijing-You chicken expressing the polydactyly phenotype provides an opportunity to investigate the potential cause for polydactyly. Here we extensively exploited genetic determinants of the chicken polydactyly in a genome wide association study using over 580,000 SNPs characterized in a Beijing-You × Lohmann F1 cross, consisting of 79 animals. A total of 10 loci clustered on the short arm of chromosome 2 were identified to be significantly associated with the trait. Among the 10 significant SNPs, 7 were located in a linkage disequilibrium block of 1737kb. The strongest association signal (rs317674023, P=5.48×10(-8)) residing nearby Bone Morphogenetic Protein Receptor-Associated Molecule 1 (BRAM1) was identified in the genomic region. Our results provide insights to the genetic basis underlying chicken polydactyly and may facilitate studies of the limb malformation in humans and other species.

  11. Comparative and parallel genome-wide association studies for metabolic and agronomic traits in cereals

    PubMed Central

    Chen, Wei; Wang, Wensheng; Peng, Meng; Gong, Liang; Gao, Yanqiang; Wan, Jian; Wang, Shouchuang; Shi, Lei; Zhou, Bin; Li, Zongmei; Peng, Xiaoxi; Yang, Chenkun; Qu, Lianghuan; Liu, Xianqing; Luo, Jie

    2016-01-01

    The plant metabolome is characterized by extensive diversity and is often regarded as a bridge between genome and phenome. Here we report metabolic and phenotypic genome-wide studies (mGWAS and pGWAS) in rice grain that, in addition to previous metabolic GWAS in rice leaf and maize kernel, show both distinct and overlapping aspects of genetic control of metabolism within and between species. We identify new candidate genes potentially influencing important metabolic and/or morphological traits. We show that the differential genetic architecture of rice metabolism between different tissues is in part determined by tissue specific expression. Using parallel mGWAS and pGWAS we identify new candidate genes potentially responsible for variation in traits such as grain colour and size, and provide evidence of metabotype-phenotype linkage. Our study demonstrates a powerful strategy for interactive functional genomics and metabolomics in plants, especially the cloning of minor QTLs for complex phenotypic traits. PMID:27698483

  12. Genome-wide association study of 12 agronomic traits in peach

    PubMed Central

    Cao, Ke; Zhou, Zhengkui; Wang, Qi; Guo, Jian; Zhao, Pei; Zhu, Gengrui; Fang, Weichao; Chen, Changwen; Wang, Xinwei; Wang, Xiaoli; Tian, Zhixi; Wang, Lirong

    2016-01-01

    Peach (Prunus persica L.) is a highly valuable crop species and is recognized by molecular researchers as a model fruit for the Rosaceae family. Using whole-genome sequencing data generated from 129 peach accessions, here we perform a comprehensive genome-wide association study for 12 key agronomic traits. We show that among the 10 qualitative traits investigated, nine exhibit consistent and more precise association signals than previously identified by linkage analysis. For two of the qualitative traits, we describe candidate genes, one potentially involved in cell death and another predicted to encode an auxin-efflux carrier, that are highly associated with fruit shape and non-acidity, respectively. Furthermore, we find that several genomic regions harbouring association signals for fruit weight and soluble solid content overlapped with predicted selective sweeps that occurred during peach domestication and improvement. Our findings contribute to the large-scale characterization of genes controlling agronomic traits in peach. PMID:27824331

  13. A re-assigned American mink (Neovison vison) map optimal for genome-wide studies.

    PubMed

    Anistoroaei, Razvan; Nielsen, Vivi; Markakis, Marios Nektarios; Karlskov-Mortensen, Peter; Jørgensen, Claus B; Christensen, Knud; Fredholm, Merete

    2012-12-10

    Our previously published second generation genetic map for the American mink (Neovison vison) has been used and redesigned in its best for genome-wide studies with maximum of efficiency. A number of 114 selected markers, including 33 newly developed microsatellite markers from the CHORI-231 mink Bacterial Artificial Chromosome (BAC) library, have been genotyped in a two generation population composed of 1200 individuals. The outcome reassigns the position of some markers on the chromosomes and it produces a more reliable map with a convenient distance between markers. A total of 104 markers mapped to 14 linkage groups corresponding to the mink autosomes. Six markers are unlinked and four markers are allocated to the X chromosome by homology but no linkage was detected. The sex-average linkage map spans 1192 centiMorgans (cM) with an average intermarker distance of 11.4cM and 1648cM when the ends of the linkage groups and the autosomal unlinked markers are added. Sex-specific genetic linkage maps were also generated. The male sex-specific map had a total length of 1014.6cM between the linked markers and an average inter-marker interval of 9.7cM. The female map has a corresponding length of 1378.6cM and an average inter-marker interval of 13.3cM. The study is complemented with additional anchorage for most of the chromosomes of the map by BAC in situ hybridization with clones containing microsatellites strategically selected from the various parts of the genome. This map provides an improved tool for genetic mapping and comparative genomics in mink, also useful for the future assembly of the mink genome sequence when this will be taken forward. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Genome-wide association analysis reveals new targets for carotenoid biofortification in maize.

    PubMed

    Suwarno, Willy B; Pixley, Kevin V; Palacios-Rojas, Natalia; Kaeppler, Shawn M; Babu, Raman

    2015-05-01

    Genome-wide association analysis in CIMMYT's association panel revealed new favorable native genomic variations in/nearby important genes such as hydroxylases and CCD1 that have potential for carotenoid biofortification in maize. Genome-wide association studies (GWAS) have been used extensively to identify allelic variation for genes controlling important agronomic and nutritional traits in plants. Provitamin A (proVA) enhancing alleles of lycopene epsilon cyclase (LCYE) and β-carotene hydroxylase 1 (CRTRB1), previously identified through candidate-gene based GWAS, are currently used in CIMMYT's maize breeding program. The objective of this study was to identify genes or genomic regions controlling variation for carotenoid concentrations in grain for CIMMYT's carotenoid association mapping panel of 380 inbred maize lines, using high-density genome-wide platforms with ~476,000 SNP markers. Population structure effects were minimized by adjustments using principal components and kinship matrix with mixed models. Genome-wide linkage disequilibrium (LD) analysis indicated faster LD decay (3.9 kb; r (2) = 0.1) than commonly reported for temperate germplasm, and therefore the possibility of achieving higher mapping resolution with our mostly tropical diversity panel. GWAS for various carotenoids identified CRTRB1, LCYE and other key genes or genomic regions that govern rate-critical steps in the upstream pathway, such as DXS1, GGPS1, and GGPS2 that are known to play important roles in the accumulation of precursor isoprenoids as well as downstream genes HYD5, CCD1, and ZEP1, which are involved in hydroxylation and carotenoid degradation. SNPs at or near all of these regions were identified and may be useful target regions for carotenoid biofortification breeding efforts in maize; for example a genomic region on chromosome 2 explained ~16% of the phenotypic variance for β-carotene independently of CRTRB1, and a variant of CCD1 that resulted in reduced

  15. FVGWAS: Fast Voxelwise Genome Wide Association Analysis of Large-scale Imaging Genetic Data 1

    PubMed Central

    Huang, Meiyan; Nichols, Thomas; Huang, Chao; Yang, Yu; Lu, Zhaohua; Feng, Qianjing; Knickmeyer, Rebecca C; Zhu, Hongtu

    2015-01-01

    More and more large-scale imaging genetic studies are being widely conducted to collect a rich set of imaging, genetic, and clinical data to detect putative genes for complexly inherited neuropsychiatric and neurodegenerative disorders. Several major big-data challenges arise from testing genome-wide (NC > 12 million known variants) associations with signals at millions of locations (NV ~ 106) in the brain from thousands of subjects (n ~ 103). The aim of this paper is to develop a Fast Voxelwise Genome Wide Association analysiS (FVGWAS) framework to e ciently carry out whole-genome analyses of whole-brain data. FVGWAS consists of three components including a heteroscedastic linear model, a global sure independence screening (G-SIS) procedure, and a detection procedure based on wild bootstrap methods. Specifically, for standard linear association, the computational complexity is O(nNV NC) for voxelwise genome wide association analysis (VGWAS) method compared with O((NC + NV)n2) for FVGWAS. Simulation studies show that FVGWAS is an effcient method of searching sparse signals in an extremely large search space, while controlling for the family-wise error rate. Finally, we have successfully applied FVGWAS to a large-scale imaging genetic data analysis of ADNI data with 708 subjects, 193,275 voxels in RAVENS maps, and 501,584 SNPs, and the total processing time was 203,645 seconds for a single CPU. Our FVG-WAS may be a valuable statistical toolbox for large-scale imaging genetic analysis as the field is rapidly advancing with ultra-high-resolution imaging and whole-genome sequencing. PMID:26025292

  16. Genome-wide QTL mapping of nine body composition and bone mineral density traits in pigs.

    PubMed

    Rothammer, Sophie; Kremer, Prisca V; Bernau, Maren; Fernandez-Figares, Ignacio; Pfister-Schär, Jennifer; Medugorac, Ivica; Scholz, Armin M

    2014-10-28

    Since the pig is one of the most important livestock animals worldwide, mapping loci that are associated with economically important traits and/or traits that influence animal welfare is extremely relevant for efficient future pig breeding. Therefore, the purpose of this study was a genome-wide mapping of quantitative trait loci (QTL) associated with nine body composition and bone mineral traits: absolute (Fat, Lean) and percentage (FatPC, LeanPC) fat and lean mass, live weight (Weight), soft tissue X-ray attenuation coefficient (R), absolute (BMC) and percentage (BMCPC) bone mineral content and bone mineral density (BMD). Data on the nine traits investigated were obtained by Dual-energy X-ray absorptiometry for 551 pigs that were between 160 and 200 days old. In addition, all pigs were genotyped using Illumina's PorcineSNP60 Genotyping BeadChip. Based on these data, a genome-wide combined linkage and linkage disequilibrium analysis was conducted. Thus, we used 44 611 sliding windows that each consisted of 20 adjacent single nucleotide polymorphisms (SNPs). For the middle of each sliding window a variance component analysis was carried out using ASReml. The underlying mixed linear model included random QTL and polygenic effects, with fixed effects of sex, housing, season and age. Using a Bonferroni-corrected genome-wide significance threshold of P < 0.001, significant peaks were identified for all traits except BMCPC. Overall, we identified 72 QTL on 16 chromosomes, of which 24 were significantly associated with one trait only and the remaining with more than one trait. For example, a QTL on chromosome 2 included the highest peak across the genome for four traits (Fat, FatPC, LeanPC and R). The nearby gene, ZNF608, is known to be associated with body mass index in humans and involved in starvation in Drosophila, which makes it an extremely good candidate gene for this QTL. Our QTL mapping approach identified 72 QTL, some of which confirmed results of previous

  17. Genome-wide Association Study of Obsessive-Compulsive Disorder

    PubMed Central

    Stewart, S Evelyn; Yu, Dongmei; Scharf, Jeremiah M; Neale, Benjamin M; Fagerness, Jesen A; Mathews, Carol A; Arnold, Paul D; Evans, Patrick D; Gamazon, Eric R; Osiecki, Lisa; McGrath, Lauren; Haddad, Stephen; Crane, Jacquelyn; Hezel, Dianne; Illman, Cornelia; Mayerfeld, Catherine; Konkashbaev, Anuar; Liu, Chunyu; Pluzhnikov, Anna; Tikhomirov, Anna; Edlund, Christopher K; Rauch, Scott L; Moessner, Rainald; Falkai, Peter; Maier, Wolfgang; Ruhrmann, Stephan; Grabe, Hans-Jörgen; Lennertz, Leonard; Wagner, Michael; Bellodi, Laura; Cavallini, Maria Cristina; Richter, Margaret A; Cook, Edwin H; Kennedy, James L; Rosenberg, David; Stein, Dan J; Hemmings, Sian MJ; Lochner, Christine; Azzam, Amin; Chavira, Denise A; Fournier, Eduardo; Garrido, Helena; Sheppard, Brooke; Umaña, Paul; Murphy, Dennis L; Wendland, Jens R; Veenstra-VanderWeele, Jeremy; Denys, Damiaan; Blom, Rianne; Deforce, Dieter; Van Nieuwerburgh, Filip; Westenberg, Herman GM; Walitza, Susanne; Egberts, Karin; Renner, Tobias; Miguel, Euripedes Constantino; Cappi, Carolina; Hounie, Ana G; Conceição do Rosário, Maria; Sampaio, Aline S; Vallada, Homero; Nicolini, Humberto; Lanzagorta, Nuria; Camarena, Beatriz; Delorme, Richard; Leboyer, Marion; Pato, Carlos N; Pato, Michele T; Voyiaziakis, Emanuel; Heutink, Peter; Cath, Danielle C; Posthuma, Danielle; Smit, Jan H; Samuels, Jack; Bienvenu, O Joseph; Cullen, Bernadette; Fyer, Abby J; Grados, Marco A; Greenberg, Benjamin D; McCracken, James T; Riddle, Mark A; Wang, Ying; Coric, Vladimir; Leckman, James F; Bloch, Michael; Pittenger, Christopher; Eapen, Valsamma; Black, Donald W; Ophoff, Roel A; Strengman, Eric; Cusi, Daniele; Turiel, Maurizio; Frau, Francesca; Macciardi, Fabio; Gibbs, J Raphael; Cookson, Mark R; Singleton, Andrew; Hardy, John; Crenshaw, Andrew T; Parkin, Melissa A; Mirel, Daniel B; Conti, David V; Purcell, Shaun; Nestadt, Gerald; Hanna, Gregory L; Jenike, Michael A; Knowles, James A; Cox, Nancy; Pauls, David L

    2014-01-01

    Obsessive-compulsive disorder (OCD) is a common, debilitating neuropsychiatric illness with complex genetic etiology. The International OCD Foundation Genetics Collaborative (IOCDF-GC) is a multi-national collaboration established to discover the genetic variation predisposing to OCD. A set of individuals affected with DSM-IV OCD, a subset of their parents, and unselected controls, were genotyped with several different Illumina SNP microarrays. After extensive data cleaning, 1,465 cases, 5,557 ancestry-matched controls and 400 complete trios remained, with a common set of 469,410 autosomal and 9,657 X-chromosome SNPs. Ancestry-stratified case-control association analyses were conducted for three genetically-defined subpopulations and combined in two meta-analyses, with and without the trio-based analysis. In the case-control analysis, the lowest two p-values were located within DLGAP1 (p=2.49×10-6 and p=3.44×10-6), a member of the neuronal postsynaptic density complex. In the trio analysis, rs6131295, near BTBD3, exceeded the genome-wide significance threshold with a p-value=3.84 × 10-8. However, when trios were meta-analyzed with the combined case-control samples, the p-value for this variant was 3.62×10-5, losing genome-wide significance. Although no SNPs were identified to be associated with OCD at a genome-wide significant level in the combined trio-case-control sample, a significant enrichment of methylation-QTLs (p<0.001) and frontal lobe eQTLs (p=0.001) was observed within the top-ranked SNPs (p<0.01) from the trio-case-control analysis, suggesting these top signals may have a broad role in gene expression in the brain, and possibly in the etiology of OCD. PMID:22889921

  18. Genome-Wide Approaches to Drosophila Heart Development

    PubMed Central

    Frasch, Manfred

    2016-01-01

    The development of the dorsal vessel in Drosophila is one of the first systems in which key mechanisms regulating cardiogenesis have been defined in great detail at the genetic and molecular level. Due to evolutionary conservation, these findings have also provided major inputs into studies of cardiogenesis in vertebrates. Many of the major components that control Drosophila cardiogenesis were discovered based on candidate gene approaches and their functions were defined by employing the outstanding genetic tools and molecular techniques available in this system. More recently, approaches have been taken that aim to interrogate the entire genome in order to identify novel components and describe genomic features that are pertinent to the regulation of heart development. Apart from classical forward genetic screens, the availability of the thoroughly annotated Drosophila genome sequence made new genome-wide approaches possible, which include the generation of massive numbers of RNA interference (RNAi) reagents that were used in forward genetic screens, as well as studies of the transcriptomes and proteomes of the developing heart under normal and experimentally manipulated conditions. Moreover, genome-wide chromatin immunoprecipitation experiments have been performed with the aim to define the full set of genomic binding sites of the major cardiogenic transcription factors, their relevant target genes, and a more complete picture of the regulatory network that drives cardiogenesis. This review will give an overview on these genome-wide approaches to Drosophila heart development and on computational analyses of the obtained information that ultimately aim to provide a description of this process at the systems level. PMID:27294102

  19. Genome Wide Association Study of Sepsis in Extremely Premature Infants

    PubMed Central

    Srinivasan, Lakshmi; Page, Grier; Kirpalani, Haresh; Murray, Jeffrey C.; Das, Abhik; Higgins, Rosemary D.; Carlo, Waldemar A.; Bell, Edward F.; Goldberg, Ronald N.; Schibler, Kurt; Sood, Beena G.; Stevenson, David K.; Stoll, Barbara J.; Van Meurs, Krisa P.; Johnson, Karen J.; Levy, Joshua; McDonald, Scott A.; Zaterka-Baxter, Kristin M.; Kennedy, Kathleen A.; Sánchez, Pablo J.; Duara, Shahnaz; Walsh, Michele C.; Shankaran, Seetha; Wynn, James L.; Cotten, C. Michael

    2017-01-01

    Objective To identify genetic variants associated with sepsis (early and late-onset) using a genome wide association (GWA) analysis in a cohort of extremely premature infants. Study Design Previously generated GWA data from the Neonatal Research Network’s anonymized genomic database biorepository of extremely premature infants were used for this study. Sepsis was defined as culture-positive early-onset or late-onset sepsis or culture-proven meningitis. Genomic and whole genome amplified DNA was genotyped for 1.2 million single nucleotide polymorphisms (SNPs); 91% of SNPs were successfully genotyped. We imputed 7.2 million additional SNPs. P values and false discovery rates were calculated from multivariate logistic regression analysis adjusting for gender, gestational age and ancestry. Target statistical value was p<10−5. Secondary analyses assessed associations of SNPs with pathogen type. Pathway analyses were also run on primary and secondary end points. Results Data from 757 extremely premature infants were included: 351 infants with sepsis and 406 infants without sepsis. No SNPs reached genome-wide significance levels (5×10−8); two SNPs in proximity to FOXC2 and FOXL1 genes achieved target levels of significance. In secondary analyses, SNPs for ELMO1, IRAK2 (Gram positive sepsis), RALA, IMMP2L (Gram negative sepsis) and PIEZO2 (fungal sepsis) met target significance levels. Pathways associated with sepsis and Gram negative sepsis included gap junctions, fibroblast growth factor receptors, regulators of cell division and Interleukin-1 associated receptor kinase 2 (p values<0.001 and FDR<20%). Conclusions No SNPs met genome-wide significance in this cohort of ELBW infants; however, areas of potential association and pathways meriting further study were identified. PMID:28283553

  20. Genome-Wide Association Study of Metabolic Syndrome in Koreans

    PubMed Central

    Jeong, Seok Won; Chung, Myungguen; Park, Soo-Jung; Cho, Seong Beom

    2014-01-01

    Metabolic syndrome (METS) is a disorder of energy utilization and storage and increases the risk of developing cardiovascular disease and diabetes. To identify the genetic risk factors of METS, we carried out a genome-wide association study (GWAS) for 2,657 cases and 5,917 controls in Korean populations. As a result, we could identify 2 single nucleotide polymorphisms (SNPs) with genome-wide significance level p-values (<5 × 10-8), 8 SNPs with genome-wide suggestive p-values (5 × 10-8 ≤ p < 1 × 10-5), and 2 SNPs of more functional variants with borderline p-values (5 × 10-5 ≤ p < 1 × 10-4). On the other hand, the multiple correction criteria of conventional GWASs exclude false-positive loci, but simultaneously, they discard many true-positive loci. To reconsider the discarded true-positive loci, we attempted to include the functional variants (nonsynonymous SNPs [nsSNPs] and expression quantitative trait loci [eQTL]) among the top 5,000 SNPs based on the proportion of phenotypic variance explained by genotypic variance. In total, 159 eQTLs and 18 nsSNPs were presented in the top 5,000 SNPs. Although they should be replicated in other independent populations, 6 eQTLs and 2 nsSNP loci were located in the molecular pathways of LPL, APOA5, and CHRM2, which were the significant or suggestive loci in the METS GWAS. Conclusively, our approach using the conventional GWAS, reconsidering functional variants and pathway-based interpretation, suggests a useful method to understand the GWAS results of complex traits and can be expanded in other genomewide association studies. PMID:25705157

  1. Voxelwise genome-wide association study (vGWAS)

    PubMed Central

    Stein, Jason L.; Hua, Xue; Lee, Suh; Ho, April J.; Leow, Alex D.; Toga, Arthur W.; Saykin, Andrew J.; Shen, Li; Foroud, Tatiana; Pankratz, Nathan; Huentelman, Matthew J.; Craig, David W.; Gerber, Jill D.; Allen, April N.; Corneveaux, Jason J.; DeChairo, Bryan M.; Potkin, Steven G.; Weiner, Michael W.; Thompson, Paul M.

    2010-01-01

    The structure of the human brain is highly heritable, and is thought to be influenced by many common genetic variants, many of which are currently unknown. Recent advances in neuroimaging and genetics have allowed collection of both highly detailed structural brain scans and genome-wide genotype information. This wealth of information presents a new opportunity to find the genes influencing brain structure. Here we explore the relation between 448,293 single nucleotide polymorphisms in each of 31,622 voxels of the entire brain across 740 elderly subjects (mean age±s.d.: 75.52±6.82 years; 438 male) including subjects with Alzheimer's disease, Mild Cognitive Impairment, and healthy elderly controls from the Alzheimer's Disease Neuroimaging Initiative (ADNI). We used tensor-based morphometry to measure individual differences in brain structure at the voxel level relative to a study-specific template based on healthy elderly subjects. We then conducted a genome-wide association at each voxel to identify genetic variants of interest. By studying only the most associated variant at each voxel, we developed a novel method to address the multiple comparisons problem and computational burden associated with the unprecedented amount of data. No variant survived the strict significance criterion, but several genes worthy of further exploration were identified, including CSMD2 and CADPS2. These genes have high relevance to brain structure. This is the first voxelwise genome wide association study to our knowledge, and offers a novel method to discover genetic influences on brain structure. PMID:20171287

  2. Genome-Wide Association of Heroin Dependence in Han Chinese.

    PubMed

    Kalsi, Gursharan; Euesden, Jack; Coleman, Jonathan R I; Ducci, Francesca; Aliev, Fazil; Newhouse, Stephen J; Liu, Xiehe; Ma, Xiaohong; Wang, Yingcheng; Collier, David A; Asherson, Philip; Li, Tao; Breen, Gerome

    2016-01-01

    Drug addiction is a costly and recurring healthcare problem, necessitating a need to understand risk factors and mechanisms of addiction, and to identify new biomarkers. To date, genome-wide association studies (GWAS) for heroin addiction have been limited; moreover they have been restricted to examining samples of European and African-American origin due to difficulty of recruiting samples from other populations. This is the first study to test a Han Chinese population; we performed a GWAS on a homogeneous sample of 370 Han Chinese subjects diagnosed with heroin dependence using the DSM-IV criteria and 134 ethnically matched controls. Analysis using the diagnostic criteria of heroin dependence yielded suggestive evidence for association between variants in the genes CCDC42 (coiled coil domain 42; p = 2.8x10-7) and BRSK2 (BR serine/threonine 2; p = 4.110-6). In addition, we found evidence for risk variants within the ARHGEF10 (Rho guanine nucleotide exchange factor 10) gene on chromosome 8 and variants in a region on chromosome 20q13, which is gene-poor but has a concentration of mRNAs and predicted miRNAs. Gene-based association analysis identified genome-wide significant association between variants in CCDC42 and heroin addiction. Additionally, when we investigated shared risk variants between heroin addiction and risk of other addiction-related and psychiatric phenotypes using polygenic risk scores, we found a suggestive relationship with variants predicting tobacco addiction, and a significant relationship with variants predicting schizophrenia. Our genome wide association study of heroin dependence provides data in a novel sample, with functionally plausible results and evidence of genetic data of value to the field.

  3. Genome-Wide Association of Heroin Dependence in Han Chinese

    PubMed Central

    Coleman, Jonathan R. I.; Ducci, Francesca; Aliev, Fazil; Newhouse, Stephen J.; Liu, Xiehe; Ma, Xiaohong; Wang, Yingcheng; Collier, David A.; Asherson, Philip; Li, Tao; Breen, Gerome

    2016-01-01

    Drug addiction is a costly and recurring healthcare problem, necessitating a need to understand risk factors and mechanisms of addiction, and to identify new biomarkers. To date, genome-wide association studies (GWAS) for heroin addiction have been limited; moreover they have been restricted to examining samples of European and African-American origin due to difficulty of recruiting samples from other populations. This is the first study to test a Han Chinese population; we performed a GWAS on a homogeneous sample of 370 Han Chinese subjects diagnosed with heroin dependence using the DSM-IV criteria and 134 ethnically matched controls. Analysis using the diagnostic criteria of heroin dependence yielded suggestive evidence for association between variants in the genes CCDC42 (coiled coil domain 42; p = 2.8x10-7) and BRSK2 (BR serine/threonine 2; p = 4.110−6). In addition, we found evidence for risk variants within the ARHGEF10 (Rho guanine nucleotide exchange factor 10) gene on chromosome 8 and variants in a region on chromosome 20q13, which is gene-poor but has a concentration of mRNAs and predicted miRNAs. Gene-based association analysis identified genome-wide significant association between variants in CCDC42 and heroin addiction. Additionally, when we investigated shared risk variants between heroin addiction and risk of other addiction-related and psychiatric phenotypes using polygenic risk scores, we found a suggestive relationship with variants predicting tobacco addiction, and a significant relationship with variants predicting schizophrenia. Our genome wide association study of heroin dependence provides data in a novel sample, with functionally plausible results and evidence of genetic data of value to the field. PMID:27936112

  4. Genome-wide association study of parity in Bangladeshi women.

    PubMed

    Aschebrook-Kilfoy, Briseis; Argos, Maria; Pierce, Brandon L; Tong, Lin; Jasmine, Farzana; Roy, Shantanu; Parvez, Faruque; Ahmed, Alauddin; Islam, Tariqul; Kibriya, Muhammad G; Ahsan, Habibul

    2015-01-01

    Human fertility is a complex trait determined by gene-environment interactions in which genetic factors represent a significant component. To better understand inter-individual variability in fertility, we performed one of the first genome-wide association studies (GWAS) of common fertility phenotypes, lifetime number of pregnancies and number of children in a developing country population. The fertility phenotype data and DNA samples were obtained at baseline recruitment from individuals participating in a large prospective cohort study in Bangladesh. GWAS analyses of fertility phenotypes were conducted among 1,686 married women. One SNP on chromosome 4 was non-significantly associated with number of children at P <10(-7) and number of pregnancies at P <10(-6). This SNP is located in a region without a gene within 1 Mb. One SNP on chromosome 6 was non-significantly associated with extreme number of children at P <10(-6). The closest gene to this SNP is HDGFL1, a hepatoma-derived growth factor. When we excluded hormonal contraceptive users, a SNP on chromosome 5 was non-significantly associated at P <10(-5) for number of children and number of pregnancies. This SNP is located near C5orf64, an open reading frame, and ZSWIM6, a zinc ion binding gene. We also estimated the heritability of these phenotypes from our genotype data using GCTA (Genome-wide Complex Trait Analysis) for number of children (hg2 = 0.149, SE = 0.24, p-value = 0.265) and number of pregnancies (hg2 = 0.007, SE = 0.22, p-value = 0.487). Our genome-wide association study and heritability estimates of number of pregnancies and number of children in Bangladesh did not confer strong evidence of common variants for parity variation. However, our results suggest that future studies may want to consider the role of 3 notable SNPs in their analysis.

  5. Genome-wide association study of conduct disorder symptomatology

    PubMed Central

    Dick, DM; Aliev, F; Krueger, RF; Edwards, A; Agrawal, A; Lynskey, M; Lin, P; Schuckit, M; Hesselbrock, V; Nurnberger, J; Almasy, L; Porjesz, B; Edenberg, HJ; Bucholz, K; Kramer, J; Kuperman, S; Bierut, L

    2013-01-01

    Conduct disorder (CD) is one of the most prevalent childhood psychiatric conditions, and is associated with a number of serious concomitant and future problems. CD symptomatology is known to have a considerable genetic component, with heritability estimates in the range of 50%. Despite this, there is a relative paucity of studies aimed at identifying genes involved in the susceptibility to CD. In this study, we report results from a genome-wide association study of CD symptoms. CD symptoms were retrospectively reported by a psychiatric interview among a sample of cases and controls, in which cases met the criteria for alcohol dependence. Our primary phenotype was the natural log transformation of the number of CD symptoms that were endorsed, with data available for 3963 individuals who were genotyped on the Illumina Human 1M beadchip array. Secondary analyses are presented for case versus control status, in which caseness was established as endorsing three or more CD symptoms (N= 872 with CD and N= 3091 without CD). We find four markers that meet the criteria for genome-wide significance (P < 5 × 10−8) with the CD symptom count, two of which are located in the gene C1QTNF7 (C1q and tumor necrosis factor-related protein 7). There were six additional SNPs in the gene that yielded converging evidence of association. These data provide the first evidence of a specific gene that is associated with CD symptomatology. None of the top signals resided in traditional candidate genes, underscoring the importance of a genome-wide approach for identifying novel variants involved in this serious childhood disorder. PMID:20585324

  6. Genome-Wide Association Study Identifies African-Specific Susceptibility Loci in African Americans With Inflammatory Bowel Disease.

    PubMed

    Brant, Steven R; Okou, David T; Simpson, Claire L; Cutler, David J; Haritunians, Talin; Bradfield, Jonathan P; Chopra, Pankaj; Prince, Jarod; Begum, Ferdouse; Kumar, Archana; Huang, Chengrui; Venkateswaran, Suresh; Datta, Lisa W; Wei, Zhi; Thomas, Kelly; Herrinton, Lisa J; Klapproth, Jan-Micheal A; Quiros, Antonio J; Seminerio, Jenifer; Liu, Zhenqiu; Alexander, Jonathan S; Baldassano, Robert N; Dudley-Brown, Sharon; Cross, Raymond K; Dassopoulos, Themistocles; Denson, Lee A; Dhere, Tanvi A; Dryden, Gerald W; Hanson, John S; Hou, Jason K; Hussain, Sunny Z; Hyams, Jeffrey S; Isaacs, Kim L; Kader, Howard; Kappelman, Michael D; Katz, Jeffry; Kellermayer, Richard; Kirschner, Barbara S; Kuemmerle, John F; Kwon, John H; Lazarev, Mark; Li, Ellen; Mack, David; Mannon, Peter; Moulton, Dedrick E; Newberry, Rodney D; Osuntokun, Bankole O; Patel, Ashish S; Saeed, Shehzad A; Targan, Stephan R; Valentine, John F; Wang, Ming-Hsi; Zonca, Martin; Rioux, John D; Duerr, Richard H; Silverberg, Mark S; Cho, Judy H; Hakonarson, Hakon; Zwick, Michael E; McGovern, Dermot P B; Kugathasan, Subra

    2017-01-01

    The inflammatory bowel diseases (IBD) ulcerative colitis (UC) and Crohn's disease (CD) cause significant morbidity and are increasing in prevalence among all populations, including African Americans. More than 200 susceptibility loci have been identified in populations of predominantly European ancestry, but few loci have been associated with IBD in other ethnicities. We performed 2 high-density, genome-wide scans comprising 2345 cases of African Americans with IBD (1646 with CD, 583 with UC, and 116 inflammatory bowel disease unclassified) and 5002 individuals without IBD (controls, identified from the Health Retirement Study and Kaiser Permanente database). Single-nucleotide polymorphisms (SNPs) associated at P < 5.0 × 10(-8) in meta-analysis with a nominal evidence (P < .05) in each scan were considered to have genome-wide significance. We detected SNPs at HLA-DRB1, and African-specific SNPs at ZNF649 and LSAMP, with associations of genome-wide significance for UC. We detected SNPs at USP25 with associations of genome-wide significance for IBD. No associations of genome-wide significance were detected for CD. In addition, 9 genes previously associated with IBD contained SNPs with significant evidence for replication (P < 1.6 × 10(-6)): ADCY3, CXCR6, HLA-DRB1 to HLA-DQA1 (genome-wide significance on conditioning), IL12B,PTGER4, and TNC for IBD; IL23R, PTGER4, and SNX20 (in strong linkage disequilibrium with NOD2) for CD; and KCNQ2 (near TNFRSF6B) for UC. Several of these genes, such as TNC (near TNFSF15), CXCR6, and genes associated with IBD at the HLA locus, contained SNPs with unique association patterns with African-specific alleles. We performed a genome-wide association study of African Americans with IBD and identified loci associated with UC in only this population; we also replicated IBD, CD, and UC loci identified in European populations. The detection of variants associated with IBD risk in only people of African descent demonstrates the

  7. Genome-wide association study (GWAS) for growth rate and age at sexual maturation in Atlantic salmon (Salmo salar).

    PubMed

    Gutierrez, Alejandro P; Yáñez, José M; Fukui, Steve; Swift, Bruce; Davidson, William S

    2015-01-01

    Early sexual maturation is considered a serious drawback for Atlantic salmon aquaculture as it retards growth, increases production times and affects flesh quality. Although both growth and sexual maturation are thought to be complex processes controlled by several genetic and environmental factors, selection for these traits has been continuously accomplished since the beginning of Atlantic salmon selective breeding programs. In this genome-wide association study (GWAS) we used a 6.5K single-nucleotide polymorphism (SNP) array to genotype ∼ 480 individuals from the Cermaq Canada broodstock program and search for SNPs associated with growth and age at sexual maturation. Using a mixed model approach we identified markers showing a significant association with growth, grilsing (early sexual maturation) and late sexual maturation. The most significant associations were found for grilsing, with markers located in Ssa10, Ssa02, Ssa13, Ssa25 and Ssa12, and for late maturation with markers located in Ssa28, Ssa01 and Ssa21. A lower level of association was detected with growth on Ssa13. Candidate genes, which were linked to these genetic markers, were identified and some of them show a direct relationship with developmental processes, especially for those in association with sexual maturation. However, the relatively low power to detect genetic markers associated with growth (days to 5 kg) in this GWAS indicates the need to use a higher density SNP array in order to overcome the low levels of linkage disequilibrium observed in Atlantic salmon before the information can be incorporated into a selective breeding program.

  8. Arabidopsis transcription factors: genome-wide comparative analysis among eukaryotes.

    PubMed

    Riechmann, J L; Heard, J; Martin, G; Reuber, L; Jiang, C; Keddie, J; Adam, L; Pineda, O; Ratcliffe, O J; Samaha, R R; Creelman, R; Pilgrim, M; Broun, P; Zhang, J Z; Ghandehari, D; Sherman, B K; Yu, G

    2000-12-15

    The completion of the Arabidopsis thaliana genome sequence allows a comparative analysis of transcriptional regulators across the three eukaryotic kingdoms. Arabidopsis dedicates over 5% of its genome to code for more than 1500 transcription factors, about 45% of which are from families specific to plants. Arabidopsis transcription factors that belong to families common to all eukaryotes do not share significant similarity with those of the other kingdoms beyond the conserved DNA binding domains, many of which have been arranged in combinations specific to each lineage. The genome-wide comparison reveals the evolutionary generation of diversity in the regulation of transcription.

  9. Genome-wide approaches to defining macrophage identity and function

    PubMed Central

    Fonseca, Gregory J; Seidman, Jason S; Glass, Christopher K

    2016-01-01

    Macrophages play essential roles in the response to injury and infection and contribute to the development and/or homeostasis of the various tissues they reside in. Conversely, macrophages also influence the pathogenesis of metabolic, neurodegenerative, and neoplastic diseases. Mechanisms that contribute to the phenotypic diversity of macrophages in health and disease remain poorly understood. Here we review the recent application of genome-wide approaches to characterize the transcriptomes and epigenetic landscapes of tissue-resident macrophages. These studies are beginning to provide insights into how distinct tissue environments are interpreted by transcriptional regulatory elements to drive specialized programs of gene expression. PMID:28087927

  10. Genome-wide approaches to understanding behaviour in Drosophila melanogaster.

    PubMed

    Neville, Megan; Goodwin, Stephen F

    2012-09-01

    Understanding how an organism exhibits specific behaviours remains a major and important biological question. Studying behaviour in a simple model organism like the fruit fly Drosophila melanogaster has the advantages of advanced molecular genetics approaches along with well-defined anatomy and physiology. With advancements in functional genomic technologies, researchers are now attempting to uncover genes and pathways involved in complex behaviours on a genome-wide scale. A systems-level network approach, which will include genomic approaches, to study behaviour will be key to understanding the regulation and modulation of behaviours and the importance of context in regulating them.

  11. Validating, augmenting and refining genome-wide association signals.

    PubMed

    Ioannidis, John P A; Thomas, Gilles; Daly, Mark J

    2009-05-01

    Studies using genome-wide platforms have yielded an unprecedented number of promising signals of association between genomic variants and human traits. This Review addresses the steps required to validate, augment and refine such signals to identify underlying causal variants for well-defined phenotypes. These steps include: large-scale exact replication across both similar and diverse populations; fine mapping and resequencing; determination of the most informative markers and multiple independent informative loci; incorporation of functional information; and improved phenotype mapping of the implicated genetic effects. Even in cases for which replication proves that an effect exists, confident localization of the causal variant often remains elusive.

  12. Genome-wide association studies and contribution to cardiovascular physiology

    PubMed Central

    Munroe, Patricia B.

    2015-01-01

    The study of family pedigrees with rare monogenic cardiovascular disorders has revealed new molecular players in physiological processes. Genome-wide association studies of complex traits with a heritable component may afford a similar and potentially intellectually richer opportunity. In this review we focus on the interpretation of genetic associations and the issue of causality in relation to known and potentially new physiology. We mainly discuss cardiometabolic traits as it reflects our personal interests, but the issues pertain broadly in many other disciplines. We also describe some of the resources that are now available that may expedite follow up of genetic association signals into observations on causal mechanisms and pathophysiology. PMID:26106147

  13. [Genome-wide association study for adolescent idiopathic scoliosis].

    PubMed

    Ogura, Yoji; Kou, Ikuyo; Scoliosis, Japan; Matsumoto, Morio; Watanabe, Kota; Ikegawa, Shiro

    2016-04-01

    Adolescent idiopathic scoliosis(AIS)is a polygenic disease. Genome-wide association studies(GWASs)have been performed for a lot of polygenic diseases. For AIS, we conducted GWAS and identified the first AIS locus near LBX1. After the discovery, we have extended our study by increasing the numbers of subjects and SNPs. In total, our Japanese GWAS has identified four susceptibility genes. GWASs for AIS have also been performed in the USA and China, which identified one and three susceptibility genes, respectively. Here we review GWASs in Japan and abroad and functional analysis to clarify the pathomechanism of AIS.

  14. [New insight of genome-wide association study (GWAS)].

    PubMed

    Hotta, Kikuko

    2013-02-01

    The number of obese patients is increasing in Japan, due to the westernization of lifestyle. Obesity, especially visceral fat obesity, is important for the development of metabolic syndrome. Genetic factors are important for the development of obesity as well as environmental factors. Importance of genetic factors of fat distribution is also reported. Recent genome-wide association studies (GWASs) have revealed the obesity and fat distribution-related polymorphisms. GWAS will highlight a better understanding of the underlying molecular mechanisms in the regulation of obesity and distribution of body fat.

  15. Genome-wide interaction analysis reveals replicated epistatic effects on brain structure

    PubMed Central

    Hibar, Derrek P.; Stein, Jason L.; Jahanshad, Neda; Kohannim, Omid; Hua, Xue; Toga, Arthur W.; McMahon, Katie L.; de Zubicaray, Greig I.; Martin, Nicholas G.; Wright, Margaret J.; Weiner, Michael W.; Thompson, Paul M.

    2015-01-01

    The discovery of several genes that affect risk for Alzheimer's disease ignited a worldwide search for Single Nucleotide Polymorphisms (SNPs), common genetic variants that affect the brain. Genome-wide search of all possible SNP-SNP interactions is challenging and rarely attempted, due to the complexity of conducting ∼1011 pairwise statistical tests. However, recent advances in machine learning, e.g., iterative sure independence screening (SIS), make it possible to analyze datasets with vastly more predictors than observations. Using an implementation of the SIS algorithm (called EPISIS), we performed a genome-wide interaction analysis testing all possible SNP-SNP interactions affecting regional brain volumes measured on MRI and mapped using tensor-based morphometry. We identified a significant SNP-SNP interaction between rs1345203 and rs1213205 that explains 1.9% of the variance in temporal lobe volume. We mapped the whole-brain, voxelwise effects of the interaction in the ADNI dataset and separately in an independent replication dataset of healthy twins (QTIM). Each additional loading in the interaction effect was associated with ∼5% greater brain regional brain volume (a protective effect) in both ADNI and QTIM samples. PMID:25264344

  16. Genome-wide association study of Tourette Syndrome

    PubMed Central

    Scharf, Jeremiah M.; Yu, Dongmei; Mathews, Carol A.; Neale, Benjamin M.; Stewart, S. Evelyn; Fagerness, Jesen A; Evans, Patrick; Gamazon, Eric; Edlund, Christopher K.; Service, Susan; Tikhomirov, Anna; Osiecki, Lisa; Illmann, Cornelia; Pluzhnikov, Anna; Konkashbaev, Anuar; Davis, Lea K; Han, Buhm; Crane, Jacquelyn; Moorjani, Priya; Crenshaw, Andrew T.; Parkin, Melissa A.; Reus, Victor I.; Lowe, Thomas L.; Rangel-Lugo, Martha; Chouinard, Sylvain; Dion, Yves; Girard, Simon; Cath, Danielle C; Smit, Jan H; King, Robert A.; Fernandez, Thomas; Leckman, James F.; Kidd, Kenneth K.; Kidd, Judith R.; Pakstis, Andrew J.; State, Matthew; Herrera, Luis Diego; Romero, Roxana; Fournier, Eduardo; Sandor, Paul; Barr, Cathy L; Phan, Nam; Gross-Tsur, Varda; Benarroch, Fortu; Pollak, Yehuda; Budman, Cathy L.; Bruun, Ruth D.; Erenberg, Gerald; Naarden, Allan L; Lee, Paul C; Weiss, Nicholas; Kremeyer, Barbara; Berrío, Gabriel Bedoya; Campbell, Desmond; Silgado, Julio C. Cardona; Ochoa, William Cornejo; Restrepo, Sandra C. Mesa; Muller, Heike; Duarte, Ana V. Valencia; Lyon, Gholson J; Leppert, Mark; Morgan, Jubel; Weiss, Robert; Grados, Marco A.; Anderson, Kelley; Davarya, Sarah; Singer, Harvey; Walkup, John; Jankovic, Joseph; Tischfield, Jay A.; Heiman, Gary A.; Gilbert, Donald L.; Hoekstra, Pieter J.; Robertson, Mary M.; Kurlan, Roger; Liu, Chunyu; Gibbs, J. Raphael; Singleton, Andrew; Hardy, John; Strengman, Eric; Ophoff, Roel; Wagner, Michael; Moessner, Rainald; Mirel, Daniel B.; Posthuma, Danielle; Sabatti, Chiara; Eskin, Eleazar; Conti, David V.; Knowles, James A.; Ruiz-Linares, Andres; Rouleau, Guy A.; Purcell, Shaun; Heutink, Peter; Oostra, Ben A.; McMahon, William; Freimer, Nelson; Cox, Nancy J.; Pauls, David L.

    2012-01-01

    Tourette Syndrome (TS) is a developmental disorder that has one of the highest familial recurrence rates among neuropsychiatric diseases with complex inheritance. However, the identification of definitive TS susceptibility genes remains elusive. Here, we report the first genome-wide association study (GWAS) of TS in 1285 cases and 4964 ancestry-matched controls of European ancestry, including two European-derived population isolates, Ashkenazi Jews from North America and Israel, and French Canadians from Quebec, Canada. In a primary meta-analysis of GWAS data from these European ancestry samples, no markers achieved a genome-wide threshold of significance (p<5 × 10−8); the top signal was found in rs7868992 on chromosome 9q32 within COL27A1 (p=1.85 × 10−6). A secondary analysis including an additional 211 cases and 285 controls from two closely-related Latin-American population isolates from the Central Valley of Costa Rica and Antioquia, Colombia also identified rs7868992 as the top signal (p=3.6 × 10−7 for the combined sample of 1496 cases and 5249 controls following imputation with 1000 Genomes data). This study lays the groundwork for the eventual identification of common TS susceptibility variants in larger cohorts and helps to provide a more complete understanding of the full genetic architecture of this disorder. PMID:22889924

  17. Genome-wide identification of hypoxia-induced enhancer regions

    PubMed Central

    Preston, Jessica L.; Randel, Melissa A.; Johnson, Eric A.

    2015-01-01

    Here we present a genome-wide method for de novo identification of enhancer regions. This approach enables massively parallel empirical investigation of DNA sequences that mediate transcriptional activation and provides a platform for discovery of regulatory modules capable of driving context-specific gene expression. The method links fragmented genomic DNA to the transcription of randomer molecule identifiers and measures the functional enhancer activity of the library by massively parallel sequencing. We transfected a Drosophila melanogaster library into S2 cells in normoxia and hypoxia, and assayed 4,599,881 genomic DNA fragments in parallel. The locations of the enhancer regions strongly correlate with genes up-regulated after hypoxia and previously described enhancers. Novel enhancer regions were identified and integrated with RNAseq data and transcription factor motifs to describe the hypoxic response on a genome-wide basis as a complex regulatory network involving multiple stress-response pathways. This work provides a novel method for high-throughput assay of enhancer activity and the genome-scale identification of 31 hypoxia-activated enhancers in Drosophila. PMID:26713262

  18. A genome-wide association study for malignant mesothelioma risk.

    PubMed

    Cadby, Gemma; Mukherjee, Sutapa; Musk, A W Bill; Reid, Alison; Garlepp, Mike; Dick, Ian; Robinson, Cleo; Hui, Jennie; Fiorito, Giovanni; Guarrera, Simonetta; Beilby, John; Melton, Phillip E; Moses, Eric K; Ugolini, Donatella; Mirabelli, Dario; Bonassi, Stefano; Magnani, Corrado; Dianzani, Irma; Matullo, Giuseppe; Robinson, Bruce; Creaney, Jenette; Palmer, Lyle J

    2013-10-01

    Malignant mesothelioma (MM) is a uniformly fatal tumour of mesothelial cells. MM is caused by exposure to asbestos however most individuals with documented asbestos exposure do not develop MM. Although MM appears to aggregate within families, the genetics of MM susceptibility is a relatively unexplored area. The aim of the current study was to identify genetic factors that contribute to MM risk. A genome-wide association analysis of 2,508,203 single nucleotide polymorphisms (SNPs) from 428 MM cases and 1269 controls from Western Australia was performed. Additional genotyping was performed on a sample of 778 asbestos-exposed Western Australian controls. Replication of the most strongly associated SNPs was undertaken in an independent case-control study of 392 asbestos-exposed cases and 367 asbestos-exposed controls from Italy. No SNPs achieved formal genome-wide statistical significance in the Western Australian study. However, suggestive results for MM risk were identified in the SDK1, CRTAM and RASGRF2 genes, and in the 2p12 chromosomal region. These findings were not replicated in the Italian study, although there was some evidence of replication in the region of SDK1. These suggestive associations will be further investigated in sequencing and functional studies. Copyright © 2013. Published by Elsevier Ireland Ltd.

  19. A Genome-Wide Association Study of Aging

    PubMed Central

    Walter, Stefan; Atzmon, Gil; Demerath, Ellen W.; Garcia, Melissa E.; Kaplan, Robert C.; Kumari, Meena; Lunetta, Kathryn L.; Milaneschi, Yuri; Tanaka, Toshiko; Tranah, Gregory J.; Völker, Uwe; Yu, Lei; Arnold, Alice; Benjamin, Emelia J.; Biffar, Reiner; Buchman, Aron S.; Boerwinkle, Eric; Couper, David; De Jager, Philip L.; Evans, Denis A.; Harris, Tamara B.; Hoffmann, Wolfgang; Hofman, Albert; Karasik, David; Kiel, Douglas P.; Kocher, Thomas; Kuningas, Maris; Launer, Lenore J.; Lohman, Kurt K.; Lutsey, Pamela L.; Mackenbach, Johan; Marciante, Kristin; Psaty, Bruce M.; Reiman, Eric M.; Rotter, Jerome I.; Seshadri, Sudha; Shardell, Michelle D.; Smith, Albert V.; van Duijn, Cornelia; Walston, Jeremy; Zillikens, M. Carola; Bandinelli, Stefania; Baumeister, Sebastian E.; Bennett, David A.; Ferrucci, Luigi; Gudnason, Vilmundur; Kivimaki, Mika; Liu, Yongmei; Murabito, Joanne M.; Newman, Anne B.; Tiemeier, Henning; Franceschini, Nora

    2011-01-01

    Human longevity and healthy aging show moderate heritability (20–50%). We conducted a meta-analysis of genome-wide association studies from nine studies from the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium for two outcomes: a) all-cause mortality and b) survival free of major disease or death. No single nucleotide polymorphism (SNP) was a genome-wide significant predictor of either outcome (p < 5 × 10−8). We found fourteen independent SNPs that predicted risk of death, and eight SNPs that predicted event-free survival (p < 10−5). These SNPs are in or near genes that are highly expressed in the brain (HECW2, HIP1, BIN2, GRIA1), genes involved in neural development and function (KCNQ4, LMO4, GRIA1, NETO1) and autophagy (ATG4C), and genes that are associated with risk of various diseases including cancer and Alzheimer’s disease. In addition to considerable overlap between the traits, pathway and network analysis corroborated these findings. These findings indicate that variation in genes involved in neurological processes may be an important factor in regulating aging free of major disease and achieving longevity. PMID:21782286

  20. Genome-wide patterns of Arabidopsis gene expression in nature.

    PubMed

    Richards, Christina L; Rosas, Ulises; Banta, Joshua; Bhambhra, Naeha; Purugganan, Michael D

    2012-01-01

    Organisms in the wild are subject to multiple, fluctuating environmental factors, and it is in complex natural environments that genetic regulatory networks actually function and evolve. We assessed genome-wide gene expression patterns in the wild in two natural accessions of the model plant Arabidopsis thaliana and examined the nature of transcriptional variation throughout its life cycle and gene expression correlations with natural environmental fluctuations. We grew plants in a natural field environment and measured genome-wide time-series gene expression from the plant shoot every three days, spanning the seedling to reproductive stages. We find that 15,352 genes were expressed in the A. thaliana shoot in the field, and accession and flowering status (vegetative versus flowering) were strong components of transcriptional variation in this plant. We identified between ∼110 and 190 time-varying gene expression clusters in the field, many of which were significantly overrepresented by genes regulated by abiotic and biotic environmental stresses. The two main principal components of vegetative shoot gene expression (PC(veg)) correlate to temperature and precipitation occurrence in the field. The largest PC(veg) axes included thermoregulatory genes while the second major PC(veg) was associated with precipitation and contained drought-responsive genes. By exposing A. thaliana to natural environments in an open field, we provide a framework for further understanding the genetic networks that are deployed in natural environments, and we connect plant molecular genetics in the laboratory to plant organismal ecology in the wild.

  1. Genome-wide association interaction analysis for Alzheimer's disease

    PubMed Central

    Gusareva, Elena S.; Carrasquillo, Minerva M.; Bellenguez, Céline; Cuyvers, Elise; Colon, Samuel; Graff-Radford, Neill R.; Petersen, Ronald C.; Dickson, Dennis W.; Mahachie Johna, Jestinah M.; Bessonov, Kyrylo; Van Broeckhoven, Christine; Williams, Julie; Amouyel, Philippe; Sleegers, Kristel; Ertekin-Taner, Nilüfer; Lambert, Jean-Charles; Van Steen, Kristel

    2015-01-01

    We propose a minimal protocol for exhaustive genome-wide association interaction analysis that involves screening for epistasis over large-scale genomic data combining strengths of different methods and statistical tools. The different steps of this protocol are illustrated on a real-life data application for Alzheimer's disease (AD) (2259 patients and 6017 controls from France). Particularly, in the exhaustive genome-wide epistasis screening we identified AD-associated interacting SNPs-pair from chromosome 6q11.1 (rs6455128, the KHDRBS2 gene) and 13q12.11 (rs7989332, the CRYL1 gene) (p = 0.006, corrected for multiple testing). A replication analysis in the independent AD cohort from Germany (555 patients and 824 controls) confirmed the discovered epistasis signal (p = 0.036). This signal was also supported by a meta-analysis approach in 5 independent AD cohorts that was applied in the context of epistasis for the first time. Transcriptome analysis revealed negative correlation between expression levels of KHDRBS2 and CRYL1 in both the temporal cortex (β = −0.19, p = 0.0006) and cerebellum (β = −0.23, p < 0.0001) brain regions. This is the first time a replicable epistasis associated with AD was identified using a hypothesis free screening approach. PMID:24958192

  2. Measuring genome-wide nucleosome turnover using CATCH-IT.

    PubMed

    Teves, Sheila S; Deal, Roger B; Henikoff, Steven

    2012-01-01

    The dynamic interplay between DNA-binding proteins and nucleosomes underlies essential nuclear processes such as transcription, replication, and DNA repair. Manifestations of this interplay include the assembly, eviction, and replacement of nucleosomes. Hence, measurements of nucleosome turnover kinetics can lead to insights into the regulation of dynamic chromatin processes. In this chapter, we describe a genome-wide method for measuring nucleosome turnover that uses metabolic labeling followed by capture of newly synthesized histones, which we have termed Covalent Attachment of Tagged Histones to Capture and Identify Turnover (CATCH-IT). Although CATCH-IT can be used with any genome-wide mapping procedure, high-resolution profiling is attainable using paired-end sequencing of native chromatin. Our protocol also includes an efficient Solexa DNA sequencing library preparation protocol that can be used for single base-pair resolution mapping of both nucleosome and subnucleosomal particles. We not only describe the use of these protocols in the context of a Drosophila cell line but also provide the necessary changes for adaptation to other model systems. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Genome-wide analysis of differential RNA editing in epilepsy.

    PubMed

    Srivastava, Prashant Kumar; Bagnati, Marta; Delahaye-Duriez, Andree; Ko, Jeong-Hun; Rotival, Maxime; Langley, Sarah R; Shkura, Kirill; Mazzuferi, Manuela; Danis, Bénédicte; van Eyll, Jonathan; Foerch, Patrik; Behmoaras, Jacques; Kaminski, Rafal M; Petretto, Enrico; Johnson, Michael R

    2017-03-01

    The recoding of genetic information through RNA editing contributes to proteomic diversity, but the extent and significance of RNA editing in disease is poorly understood. In particular, few studies have investigated the relationship between RNA editing and disease at a genome-wide level. Here, we developed a framework for the genome-wide detection of RNA sites that are differentially edited in disease. Using RNA-sequencing data from 100 hippocampi from mice with epilepsy (pilocarpine-temporal lobe epilepsy model) and 100 healthy control hippocampi, we identified 256 RNA sites (overlapping with 87 genes) that were significantly differentially edited between epileptic cases and controls. The degree of differential RNA editing in epileptic mice correlated with frequency of seizures, and the set of genes differentially RNA-edited between case and control mice were enriched for functional terms highly relevant to epilepsy, including "neuron projection" and "seizures." Genes with differential RNA editing were preferentially enriched for genes with a genetic association to epilepsy. Indeed, we found that they are significantly enriched for genes that harbor nonsynonymous de novo mutations in patients with epileptic encephalopathy and for common susceptibility variants associated with generalized epilepsy. These analyses reveal a functional convergence between genes that are differentially RNA-edited in acquired symptomatic epilepsy and those that contribute risk for genetic epilepsy. Taken together, our results suggest a potential role for RNA editing in the epileptic hippocampus in the occurrence and severity of epileptic seizures.

  4. Genome-wide mapping of DNA strand breaks.

    PubMed

    Leduc, Frédéric; Faucher, David; Bikond Nkoma, Geneviève; Grégoire, Marie-Chantal; Arguin, Mélina; Wellinger, Raymund J; Boissonneault, Guylain

    2011-02-25

    Determination of cellular DNA damage has so far been limited to global assessment of genome integrity whereas nucleotide-level mapping has been restricted to specific loci by the use of specific primers. Therefore, only limited DNA sequences can be studied and novel regions of genomic instability can hardly be discovered. Using a well-characterized yeast model, we describe a straightforward strategy to map genome-wide DNA strand breaks without compromising nucleotide-level resolution. This technique, termed "damaged DNA immunoprecipitation" (dDIP), uses immunoprecipitation and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin end-labeling (TUNEL) to capture DNA at break sites. When used in combination with microarray or next-generation sequencing technologies, dDIP will allow researchers to map genome-wide DNA strand breaks as well as other types of DNA damage and to establish a clear profiling of altered genes and/or intergenic sequences in various experimental conditions. This mapping technique could find several applications for instance in the study of aging, genotoxic drug screening, cancer, meiosis, radiation and oxidative DNA damage.

  5. A genome-wide association study of aging.

    PubMed

    Walter, Stefan; Atzmon, Gil; Demerath, Ellen W; Garcia, Melissa E; Kaplan, Robert C; Kumari, Meena; Lunetta, Kathryn L; Milaneschi, Yuri; Tanaka, Toshiko; Tranah, Gregory J; Völker, Uwe; Yu, Lei; Arnold, Alice; Benjamin, Emelia J; Biffar, Reiner; Buchman, Aron S; Boerwinkle, Eric; Couper, David; De Jager, Philip L; Evans, Denis A; Harris, Tamara B; Hoffmann, Wolfgang; Hofman, Albert; Karasik, David; Kiel, Douglas P; Kocher, Thomas; Kuningas, Maris; Launer, Lenore J; Lohman, Kurt K; Lutsey, Pamela L; Mackenbach, Johan; Marciante, Kristin; Psaty, Bruce M; Reiman, Eric M; Rotter, Jerome I; Seshadri, Sudha; Shardell, Michelle D; Smith, Albert V; van Duijn, Cornelia; Walston, Jeremy; Zillikens, M Carola; Bandinelli, Stefania; Baumeister, Sebastian E; Bennett, David A; Ferrucci, Luigi; Gudnason, Vilmundur; Kivimaki, Mika; Liu, Yongmei; Murabito, Joanne M; Newman, Anne B; Tiemeier, Henning; Franceschini, Nora

    2011-11-01

    Human longevity and healthy aging show moderate heritability (20%-50%). We conducted a meta-analysis of genome-wide association studies from 9 studies from the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium for 2 outcomes: (1) all-cause mortality, and (2) survival free of major disease or death. No single nucleotide polymorphism (SNP) was a genome-wide significant predictor of either outcome (p < 5 × 10(-8)). We found 14 independent SNPs that predicted risk of death, and 8 SNPs that predicted event-free survival (p < 10(-5)). These SNPs are in or near genes that are highly expressed in the brain (HECW2, HIP1, BIN2, GRIA1), genes involved in neural development and function (KCNQ4, LMO4, GRIA1, NETO1) and autophagy (ATG4C), and genes that are associated with risk of various diseases including cancer and Alzheimer's disease. In addition to considerable overlap between the traits, pathway and network analysis corroborated these findings. These findings indicate that variation in genes involved in neurological processes may be an important factor in regulating aging free of major disease and achieving longevity.

  6. Genome-Wide Mapping of DNA Methylation in Chicken

    PubMed Central

    Hu, Xiaoxiang; Li, Jinxiu; Du, Zhuo; Chen, Li; Yin, Guangliang; Duan, Jinjie; Zhang, Haichao; Zhao, Yaofeng; Wang, Jun; Li, Ning

    2011-01-01

    Cytosine DNA methylation is an important epigenetic modification termed as the fifth base that functions in diverse processes. Till now, the genome-wide DNA methylation maps of many organisms has been reported, such as human, Arabidopsis, rice and silkworm, but the methylation pattern of bird remains rarely studied. Here we show the genome-wide DNA methylation map of bird, using the chicken as a model organism and an immunocapturing approach followed by high-throughput sequencing. In both of the red jungle fowl and the avian broiler, DNA methylation was described separately for the liver and muscle tissue. Generally, chicken displays analogous methylation pattern with that of animals and plants. DNA methylation is enriched in the gene body regions and the repetitive sequences, and depleted in the transcription start site (TSS) and the transcription termination site (TTS). Most of the CpG islands in the chicken genome are kept in unmethylated state. Promoter methylation is negatively correlated with the gene expression level, indicating its suppressive role in regulating gene transcription. This work contributes to our understanding of epigenetics in birds. PMID:21573164

  7. A Pooled Genome-Wide Association Study of Asperger Syndrome.

    PubMed

    Warrier, Varun; Chakrabarti, Bhismadev; Murphy, Laura; Chan, Allen; Craig, Ian; Mallya, Uma; Lakatošová, Silvia; Rehnstrom, Karola; Peltonen, Leena; Wheelwright, Sally; Allison, Carrie; Fisher, Simon E; Baron-Cohen, Simon

    2015-01-01

    Asperger Syndrome (AS) is a neurodevelopmental condition characterized by impairments in social interaction and communication, alongside the presence of unusually repetitive, restricted interests and stereotyped behaviour. Individuals with AS have no delay in cognitive and language development. It is a subset of Autism Spectrum Conditions (ASC), which are highly heritable and has a population prevalence of approximately 1%. Few studies have investigated the genetic basis of AS. To address this gap in the literature, we performed a genome-wide pooled DNA association study to identify candidate loci in 612 individuals (294 cases and 318 controls) of Caucasian ancestry, using the Affymetrix GeneChip Human Mapping version 6.0 array. We identified 11 SNPs that had a p-value below 1x10-5. These SNPs were independently genotyped in the same sample. Three of the SNPs (rs1268055, rs7785891 and rs2782448) were nominally significant, though none remained significant after Bonferroni correction. Two of our top three SNPs (rs7785891 and rs2782448) lie in loci previously implicated in ASC. However, investigation of the three SNPs in the ASC genome-wide association dataset from the Psychiatric Genomics Consortium indicated that these three SNPs were not significantly associated with ASC. The effect sizes of the variants were modest, indicating that our study was not sufficiently powered to identify causal variants with precision.

  8. Genome-wide nucleotide-level mammalian ancestor reconstruction.

    PubMed

    Paten, Benedict; Herrero, Javier; Fitzgerald, Stephen; Beal, Kathryn; Flicek, Paul; Holmes, Ian; Birney, Ewan

    2008-11-01

    Recently attention has been turned to the problem of reconstructing complete ancestral sequences from large multiple alignments. Successful generation of these genome-wide reconstructions will facilitate a greater knowledge of the events that have driven evolution. We present a new evolutionary alignment modeler, called "Ortheus," for inferring the evolutionary history of a multiple alignment, in terms of both substitutions and, importantly, insertions and deletions. Based on a multiple sequence probabilistic transducer model of the type proposed by Holmes, Ortheus uses efficient stochastic graph-based dynamic programming methods. Unlike other methods, Ortheus does not rely on a single fixed alignment from which to work. Ortheus is also more scaleable than previous methods while being fast, stable, and open source. Large-scale simulations show that Ortheus performs close to optimally on a deep mammalian phylogeny. Simulations also indicate that significant proportions of errors due to insertions and deletions can be avoided by not assuming a fixed alignment. We additionally use a challenging hold-out cross-validation procedure to test the method; using the reconstructions to predict extant sequence bases, we demonstrate significant improvements over using closest extant neighbor sequences. Accompanying this paper, a new, public, and genome-wide set of Ortheus ancestor alignments provide an intriguing new resource for evolutionary studies in mammals. As a first piece of analysis, we attempt to recover "fossilized" ancestral pseudogenes. We confidently find 31 cases in which the ancestral sequence had a more complete sequence than any of the extant sequences.

  9. Genome-wide analysis of differential RNA editing in epilepsy

    PubMed Central

    Srivastava, Prashant Kumar; Bagnati, Marta; Delahaye-Duriez, Andree; Ko, Jeong-Hun; Rotival, Maxime; Langley, Sarah R.; Shkura, Kirill; Mazzuferi, Manuela; Danis, Bénédicte; van Eyll, Jonathan; Foerch, Patrik; Behmoaras, Jacques; Kaminski, Rafal M.; Petretto, Enrico; Johnson, Michael R.

    2017-01-01

    The recoding of genetic information through RNA editing contributes to proteomic diversity, but the extent and significance of RNA editing in disease is poorly understood. In particular, few studies have investigated the relationship between RNA editing and disease at a genome-wide level. Here, we developed a framework for the genome-wide detection of RNA sites that are differentially edited in disease. Using RNA-sequencing data from 100 hippocampi from mice with epilepsy (pilocarpine–temporal lobe epilepsy model) and 100 healthy control hippocampi, we identified 256 RNA sites (overlapping with 87 genes) that were significantly differentially edited between epileptic cases and controls. The degree of differential RNA editing in epileptic mice correlated with frequency of seizures, and the set of genes differentially RNA-edited between case and control mice were enriched for functional terms highly relevant to epilepsy, including “neuron projection” and “seizures.” Genes with differential RNA editing were preferentially enriched for genes with a genetic association to epilepsy. Indeed, we found that they are significantly enriched for genes that harbor nonsynonymous de novo mutations in patients with epileptic encephalopathy and for common susceptibility variants associated with generalized epilepsy. These analyses reveal a functional convergence between genes that are differentially RNA-edited in acquired symptomatic epilepsy and those that contribute risk for genetic epilepsy. Taken together, our results suggest a potential role for RNA editing in the epileptic hippocampus in the occurrence and severity of epileptic seizures. PMID:28250018

  10. A Pooled Genome-Wide Association Study of Asperger Syndrome

    PubMed Central

    Warrier, Varun; Chakrabarti, Bhismadev; Murphy, Laura; Chan, Allen; Craig, Ian; Mallya, Uma; Lakatošová, Silvia; Rehnstrom, Karola; Wheelwright, Sally; Allison, Carrie; Fisher, Simon E.; Baron-Cohen, Simon

    2015-01-01

    Asperger Syndrome (AS) is a neurodevelopmental condition characterized by impairments in social interaction and communication, alongside the presence of unusually repetitive, restricted interests and stereotyped behaviour. Individuals with AS have no delay in cognitive and language development. It is a subset of Autism Spectrum Conditions (ASC), which are highly heritable and has a population prevalence of approximately 1%. Few studies have investigated the genetic basis of AS. To address this gap in the literature, we performed a genome-wide pooled DNA association study to identify candidate loci in 612 individuals (294 cases and 318 controls) of Caucasian ancestry, using the Affymetrix GeneChip Human Mapping version 6.0 array. We identified 11 SNPs that had a p-value below 1x10-5. These SNPs were independently genotyped in the same sample. Three of the SNPs (rs1268055, rs7785891 and rs2782448) were nominally significant, though none remained significant after Bonferroni correction. Two of our top three SNPs (rs7785891 and rs2782448) lie in loci previously implicated in ASC. However, investigation of the three SNPs in the ASC genome-wide association dataset from the Psychiatric Genomics Consortium indicated that these three SNPs were not significantly associated with ASC. The effect sizes of the variants were modest, indicating that our study was not sufficiently powered to identify causal variants with precision. PMID:26176695

  11. Automated linkage analysis in psychiatric disorders

    SciTech Connect

    He, L.; Mansfield, D.C.; Brown, A.F.; Green, D.K.

    1995-06-19

    A genome-wide search for linkage of microsatellite markers to chromosomal loci containing genes responsible for the major psychoses is a laborious task which can be carried out with greater speed and economy by introducing automation to several steps in the procedure. We describe the use of the Automated Linkage Preprocessor (ALP) program for the computer analysis of the waveform generated by fluorescein-labelled markers after electrophoretic separation. (To obtain a copy send a request to A.F. Brown at the below MRC address or use Anonymous FTP to ftp.hgu.mrc.ac.uk. Software is in directory pub/ALP.) The program runs on a PC in the Microsoft Windows environment, and is used in conjunction with an automated laser fluorescence (ALF) sequencer (Pharmacia) and its Fragment Manager{trademark} software to detect and size the PCR products, filter out peaks of fluorescence due to nonallele fragments, and generate genotypes in a format suitable for direct input to standard linkage analysis programs. The method should offer the advantages of speed, accuracy, and reduced cost. Its use in linkage studies in a large family with manic-depressive illness is discussed. 14 refs., 3 figs., 1 tab.

  12. A genome-wide scan for tying-up syndrome in Japanese Thoroughbreds.

    PubMed

    Tozaki, T; Hirota, K; Sugita, S; Ishida, N; Miyake, T; Oki, H; Hasegawa, T

    2010-12-01

    Tying-up syndrome, also known as recurrent exertional rhabdomyolysis in Thoroughbreds, is a common muscle disorder for racehorses. In this study, we performed a multipoint linkage analysis using LOKI based on the Bayesian Markov chain Monte Carlo method using 5 half-sib families (51 affected and 277 nonaffected horses in total), and a genome-wide association study (GWAS) using microsatellites (144 affected and 144 nonaffected horses) to map candidate regions for tying-up syndrome in Japanese Thoroughbreds. The linkage analysis identified one strong L-score (82.45) between the loci UCDEQ411 and COR058 (24.9-27.9 Mb) on ECA12. The GWAS identified two suggestive genomic regions on ECA12 (24.9-27.8 Mb) and ECA20 (29.3-33.5 Mb). Based on both results, the genomic region between UCDEQ411 and TKY499 (24.9-27.8 Mb) on ECA12 was the most significant and was considered as a candidate region for tying-up syndrome in Japanese Thoroughbreds. © 2010 The Authors, Journal compilation © 2010 Stichting International Foundation for Animal Genetics.

  13. Quantifying the mapping precision of genome-wide association studies using whole-genome sequencing data.

    PubMed

    Wu, Yang; Zheng, Zhili; Visscher, Peter M; Yang, Jian

    2017-05-16

    Understanding the mapping precision of genome-wide association studies (GWAS), that is the physical distances between the top associated single-nucleotide polymorphisms (SNPs) and the causal variants, is essential to design fine-mapping experiments for complex traits and diseases. Using simulations based on whole-genome sequencing (WGS) data from 3642 unrelated individuals of European descent, we show that the association signals at rare causal variants (minor allele frequency ≤ 0.01) are very unlikely to be mapped to common variants in GWAS using either WGS data or imputed data and vice versa. We predict that at least 80% of the common variants identified from published GWAS using imputed data are within 33.5 Kbp of the causal variants, a resolution that is comparable with that using WGS data. Mapping precision at these loci will improve with increasing sample sizes of GWAS in the future. For rare variants, the mapping precision of GWAS using WGS data is extremely high, suggesting WGS is an efficient strategy to detect and fine-map rare variants simultaneously. We further assess the mapping precision by linkage disequilibrium between GWAS hits and causal variants and develop an online tool (gwasMP) to query our results with different thresholds of physical distance and/or linkage disequilibrium ( http://cnsgenomics.com/shiny/gwasMP ). Our findings provide a benchmark to inform future design and development of fine-mapping experiments and technologies to pinpoint the causal variants at GWAS loci.

  14. Genome-wide Pleiotropy Between Parkinson Disease and Autoimmune Diseases.

    PubMed

    Witoelar, Aree; Jansen, Iris E; Wang, Yunpeng; Desikan, Rahul S; Gibbs, J Raphael; Blauwendraat, Cornelis; Thompson, Wesley K; Hernandez, Dena G; Djurovic, Srdjan; Schork, Andrew J; Bettella, Francesco; Ellinghaus, David; Franke, Andre; Lie, Benedicte A; McEvoy, Linda K; Karlsen, Tom H; Lesage, Suzanne; Morris, Huw R; Brice, Alexis; Wood, Nicholas W; Heutink, Peter; Hardy, John; Singleton, Andrew B; Dale, Anders M; Gasser, Thomas; Andreassen, Ole A; Sharma, Manu

    2017-07-01

    Recent genome-wide association studies (GWAS) and pathway analyses supported long-standing observations of an association between immune-mediated diseases and Parkinson disease (PD). The post-GWAS era provides an opportunity for cross-phenotype analyses between different complex phenotypes. To test the hypothesis that there are common genetic risk variants conveying risk of both PD and autoimmune diseases (ie, pleiotropy) and to identify new shared genetic variants and their pathways by applying a novel statistical framework in a genome-wide approach. Using the conjunction false discovery rate method, this study analyzed GWAS data from a selection of archetypal autoimmune diseases among 138 511 individuals of European ancestry and systemically investigated pleiotropy between PD and type 1 diabetes, Crohn disease, ulcerative colitis, rheumatoid arthritis, celiac disease, psoriasis, and multiple sclerosis. NeuroX data (6927 PD cases and 6108 controls) were used for replication. The study investigated the biological correlation between the top loci through protein-protein interaction and changes in the gene expression and methylation levels. The dates of the analysis were June 10, 2015, to March 4, 2017. The primary outcome was a list of novel loci and their pathways involved in PD and autoimmune diseases. Genome-wide conjunctional analysis identified 17 novel loci at false discovery rate less than 0.05 with overlap between PD and autoimmune diseases, including known PD loci adjacent to GAK, HLA-DRB5, LRRK2, and MAPT for rheumatoid arthritis, ulcerative colitis and Crohn disease. Replication confirmed the involvement of HLA, LRRK2, MAPT, TRIM10, and SETD1A in PD. Among the novel genes discovered, WNT3, KANSL1, CRHR1, BOLA2, and GUCY1A3 are within a protein-protein interaction network with known PD genes. A subset of novel loci was significantly associated with changes in methylation or expression levels of adjacent genes. The study findings provide novel mechanistic

  15. Genome-wide association study of antisocial personality disorder

    PubMed Central

    Rautiainen, M-R; Paunio, T; Repo-Tiihonen, E; Virkkunen, M; Ollila, H M; Sulkava, S; Jolanki, O; Palotie, A; Tiihonen, J

    2016-01-01

    The pathophysiology of antisocial personality disorder (ASPD) remains unclear. Although the most consistent biological finding is reduced grey matter volume in the frontal cortex, about 50% of the total liability to developing ASPD has been attributed to genetic factors. The contributing genes remain largely unknown. Therefore, we sought to study the genetic background of ASPD. We conducted a genome-wide association study (GWAS) and a replication analysis of Finnish criminal offenders fulfilling DSM-IV criteria for ASPD (N=370, N=5850 for controls, GWAS; N=173, N=3766 for controls and replication sample). The GWAS resulted in suggestive associations of two clusters of single-nucleotide polymorphisms at 6p21.2 and at 6p21.32 at the human leukocyte antigen (HLA) region. Imputation of HLA alleles revealed an independent association with DRB1*01:01 (odds ratio (OR)=2.19 (1.53–3.14), P=1.9 × 10-5). Two polymorphisms at 6p21.2 LINC00951–LRFN2 gene region were replicated in a separate data set, and rs4714329 reached genome-wide significance (OR=1.59 (1.37–1.85), P=1.6 × 10−9) in the meta-analysis. The risk allele also associated with antisocial features in the general population conditioned for severe problems in childhood family (β=0.68, P=0.012). Functional analysis in brain tissue in open access GTEx and Braineac databases revealed eQTL associations of rs4714329 with LINC00951 and LRFN2 in cerebellum. In humans, LINC00951 and LRFN2 are both expressed in the brain, especially in the frontal cortex, which is intriguing considering the role of the frontal cortex in behavior and the neuroanatomical findings of reduced gray matter volume in ASPD. To our knowledge, this is the first study showing genome-wide significant and replicable findings on genetic variants associated with any personality disorder. PMID:27598967

  16. Susceptibility to Childhood Pneumonia: A Genome-Wide Analysis.

    PubMed

    Hayden, Lystra P; Cho, Michael H; McDonald, Merry-Lynn N; Crapo, James D; Beaty, Terri H; Silverman, Edwin K; Hersh, Craig P

    2017-01-01

    Previous studies have indicated that in adult smokers, a history of childhood pneumonia is associated with reduced lung function and chronic obstructive pulmonary disease. There have been few previous investigations using genome-wide association studies to investigate genetic predisposition to pneumonia. This study aims to identify the genetic variants associated with the development of pneumonia during childhood and over the course of the lifetime. Study subjects included current and former smokers with and without chronic obstructive pulmonary disease participating in the COPDGene Study. Pneumonia was defined by subject self-report, with childhood pneumonia categorized as having the first episode at <16 years. Genome-wide association studies for childhood pneumonia (843 cases, 9,091 control subjects) and lifetime pneumonia (3,766 cases, 5,659 control subjects) were performed separately in non-Hispanic whites and African Americans. Non-Hispanic white and African American populations were combined in the meta-analysis. Top genetic variants from childhood pneumonia were assessed in network analysis. No single-nucleotide polymorphisms reached genome-wide significance, although we identified potential regions of interest. In the childhood pneumonia analysis, this included variants in NGR1 (P = 6.3 × 10(-8)), PAK6 (P = 3.3 × 10(-7)), and near MATN1 (P = 2.8 × 10(-7)). In the lifetime pneumonia analysis, this included variants in LOC339862 (P = 8.7 × 10(-7)), RAPGEF2 (P = 8.4 × 10(-7)), PHACTR1 (P = 6.1 × 10(-7)), near PRR27 (P = 4.3 × 10(-7)), and near MCPH1 (P = 2.7 × 10(-7)). Network analysis of the genes associated with childhood pneumonia included top networks related to development, blood vessel morphogenesis, muscle contraction, WNT signaling, DNA damage, apoptosis, inflammation, and immune response (P ≤ 0.05). We have identified genes potentially associated with the risk of pneumonia

  17. Genome-wide analysis of mutations in mutant lineages selected following fast-neutron irradiation mutagenesis of Arabidopsis thaliana

    PubMed Central

    Belfield, Eric J.; Gan, Xiangchao; Mithani, Aziz; Brown, Carly; Jiang, Caifu; Franklin, Keara; Alvey, Elizabeth; Wibowo, Anjar; Jung, Marko; Bailey, Kit; Kalwani, Sharan; Ragoussis, Jiannis; Mott, Richard; Harberd, Nicholas P.

    2012-01-01

    Ionizing radiation has long been known to induce heritable mutagenic change in DNA sequence. However, the genome-wide effect of radiation is not well understood. Here we report the molecular properties and frequency of mutations in phenotypically selected mutant lines isolated following exposure of the genetic model flowering plant Arabidopsis thaliana to fast neutrons (FNs). Previous studies suggested that FNs predominantly induce deletions longer than a kilobase in A. thaliana. However, we found a higher frequency of single base substitution than deletion mutations. While the overall frequency and molecular spectrum of fast-neutron (FN)–induced single base substitutions differed substantially from those of “background” mutations arising spontaneously in laboratory-grown plants, G:C>A:T transitions were favored in both. We found that FN-induced G:C>A:T transitions were concentrated at pyrimidine dinucleotide sites, suggesting that FNs promote the formation of mutational covalent linkages between adjacent pyrimidine residues. In addition, we found that FNs induced more single base than large deletions, and that these single base deletions were possibly caused by replication slippage. Our observations provide an initial picture of the genome-wide molecular profile of mutations induced in A. thaliana by FN irradiation and are particularly informative of the nature and extent of genome-wide mutation in lines selected on the basis of mutant phenotypes from FN-mutagenized A. thaliana populations. PMID:22499668

  18. Meta-analysis of Genome-Wide Association Studies for Extraversion: Findings from the Genetics of Personality Consortium.

    PubMed

    van den Berg, Stéphanie M; de Moor, Marleen H M; Verweij, Karin J H; Krueger, Robert F; Luciano, Michelle; Arias Vasquez, Alejandro; Matteson, Lindsay K; Derringer, Jaime; Esko, Tõnu; Amin, Najaf; Gordon, Scott D; Hansell, Narelle K; Hart, Amy B; Seppälä, Ilkka; Huffman, Jennifer E; Konte, Bettina; Lahti, Jari; Lee, Minyoung; Miller, Mike; Nutile, Teresa; Tanaka, Toshiko; Teumer, Alexander; Viktorin, Alexander; Wedenoja, Juho; Abdellaoui, Abdel; Abecasis, Goncalo R; Adkins, Daniel E; Agrawal, Arpana; Allik, Jüri; Appel, Katja; Bigdeli, Timothy B; Busonero, Fabio; Campbell, Harry; Costa, Paul T; Smith, George Davey; Davies, Gail; de Wit, Harriet; Ding, Jun; Engelhardt, Barbara E; Eriksson, Johan G; Fedko, Iryna O; Ferrucci, Luigi; Franke, Barbara; Giegling, Ina; Grucza, Richard; Hartmann, Annette M; Heath, Andrew C; Heinonen, Kati; Henders, Anjali K; Homuth, Georg; Hottenga, Jouke-Jan; Iacono, William G; Janzing, Joost; Jokela, Markus; Karlsson, Robert; Kemp, John P; Kirkpatrick, Matthew G; Latvala, Antti; Lehtimäki, Terho; Liewald, David C; Madden, Pamela A F; Magri, Chiara; Magnusson, Patrik K E; Marten, Jonathan; Maschio, Andrea; Mbarek, Hamdi; Medland, Sarah E; Mihailov, Evelin; Milaneschi, Yuri; Montgomery, Grant W; Nauck, Matthias; Nivard, Michel G; Ouwens, Klaasjan G; Palotie, Aarno; Pettersson, Erik; Polasek, Ozren; Qian, Yong; Pulkki-Råback, Laura; Raitakari, Olli T; Realo, Anu; Rose, Richard J; Ruggiero, Daniela; Schmidt, Carsten O; Slutske, Wendy S; Sorice, Rossella; Starr, John M; St Pourcain, Beate; Sutin, Angelina R; Timpson, Nicholas J; Trochet, Holly; Vermeulen, Sita; Vuoksimaa, Eero; Widen, Elisabeth; Wouda, Jasper; Wright, Margaret J; Zgaga, Lina; Porteous, David; Minelli, Alessandra; Palmer, Abraham A; Rujescu, Dan; Ciullo, Marina; Hayward, Caroline; Rudan, Igor; Metspalu, Andres; Kaprio, Jaakko; Deary, Ian J; Räikkönen, Katri; Wilson, James F; Keltikangas-Järvinen, Liisa; Bierut, Laura J; Hettema, John M; Grabe, Hans J; Penninx, Brenda W J H; van Duijn, Cornelia M; Evans, David M; Schlessinger, David; Pedersen, Nancy L; Terracciano, Antonio; McGue, Matt; Martin, Nicholas G; Boomsma, Dorret I

    2016-03-01

    Extraversion is a relatively stable and heritable personality trait associated with numerous psychosocial, lifestyle and health outcomes. Despite its substantial heritability, no genetic variants have been detected in previous genome-wide association (GWA) studies, which may be due to relatively small sample sizes of those studies. Here, we report on a large meta-analysis of GWA studies for extraversion in 63,030 subjects in 29 cohorts. Extraversion item data from multiple personality inventories were harmonized across inventories and cohorts. No genome-wide significant associations were found at the single nucleotide polymorphism (SNP) level but there was one significant hit at the gene level for a long non-coding RNA site (LOC101928162). Genome-wide complex trait analysis in two large cohorts showed that the additive variance explained by common SNPs was not significantly different from zero, but polygenic risk scores, weighted using linkage information, significantly predicted extraversion scores in an independent cohort. These results show that extraversion is a highly polygenic personality trait, with an architecture possibly different from other complex human traits, including other personality traits. Future studies are required to further determine which genetic variants, by what modes of gene action, constitute the heritable nature of extraversion.

  19. In Search of Institutional Linkages for Participatory Extension in Agricultural and Rural Development.

    ERIC Educational Resources Information Center

    Duvel, G. H.

    1995-01-01

    Essential aspects of a linkage model for rural development and extension are an umbrella organization representing subcommunities and having overall coordination responsibility and program development committees. Principles include the following: development is about self-help; degree of community participation determines effectiveness; and…

  20. Externalizing disorders in American Indians: comorbidity and a genome wide linkage analysis.

    PubMed

    Ehlers, Cindy L; Gilder, David A; Slutske, Wendy S; Lind, Penelope A; Wilhelmsen, Kirk C

    2008-09-05

    Alcohol dependence is one of the leading causes of morbidity and mortality in Native Americans. Externalizing disorders such as conduct disorder (CD) and antisocial personality disorder (ASPD) have been demonstrated to have significant comorbidity with alcohol dependence in the general population. This study's aims were to: assess the comorbidity of DSM-III-R ASPD and CD with alcohol dependence, to map susceptibility loci for ASPD and CD, and to see if there is overlap with loci previously mapped for alcohol dependence phenotypes in 587 American Indians. Alcohol dependence was found to be comorbid with DSM-III-R ASPD but not CD. However, the amount of alcohol dependence in the population attributable to ASPD and/or CD is low. ASPD and the combined phenotype of participants with ASPD or CD were both found to have significant heritability, whereas no significant evidence was found for CD alone. Genotypes were determined for a panel of 791 micro-satellite polymorphisms in 251 of the participants. Analyses of multipoint variance component LOD scores, for ASPD and ASPD/CD, revealed six locations that had a LOD score of 2.0 or above: on chromosome 13 for ASPD and on chromosomes 1, 3, 4, 14, 17, and 20 for ASPD/CD. These results corroborate the importance of several chromosomal regions highlighted in prior segregation studies for externalizing diagnoses. These results also further identify new regions of the genome, that do not overlap with alcohol dependence phenotypes previously identified in this population, that may be unique to either the phenotypes evaluated or this population of American Indians.

  1. An integrated approach to exploit linkage disequilibrium for ultra high dimensional genome-wide data

    USDA-ARS?s Scientific Manuscript database

    With the advent of recent DNA sequencing methods (determining molecule order) that quickly produce millions of DNA sequences, variation among sequences in a genome (all the DNA contained in chromosomes of an organism) can be tested for association with traits of economic interest on a relatively lar...

  2. Progress of genome wide association study in domestic animals.

    PubMed

    Zhang, Hui; Wang, Zhipeng; Wang, Shouzhi; Li, Hui

    2012-08-22

    Domestic animals are invaluable resources for study of the molecular architecture of complex traits. Although the mapping of quantitative trait loci (QTL) responsible for economically important traits in domestic animals has achieved remarkable results in recent decades, not all of the genetic variation in the complex traits has been captured because of the low density of markers used in QTL mapping studies. The genome wide association study (GWAS), which utilizes high-density single-nucleotide polymorphism (SNP), provides a new way to tackle this issue. Encouraging achievements in dissection of the genetic mechanisms of complex diseases in humans have resulted from the use of GWAS. At present, GWAS has been applied to the field of domestic animal breeding and genetics, and some advances have been made. Many genes or markers that affect economic traits of interest in domestic animals have been identified. In this review, advances in the use of GWAS in domestic animals are described.

  3. Microfluidics for genome-wide studies involving next generation sequencing

    PubMed Central

    Murphy, Travis W.; Lu, Chang

    2017-01-01

    Next-generation sequencing (NGS) has revolutionized how molecular biology studies are conducted. Its decreasing cost and increasing throughput permit profiling of genomic, transcriptomic, and epigenomic features for a wide range of applications. Microfluidics has been proven to be highly complementary to NGS technology with its unique capabilities for handling small volumes of samples and providing platforms for automation, integration, and multiplexing. In this article, we review recent progress on applying microfluidics to facilitate genome-wide studies. We emphasize on several technical aspects of NGS and how they benefit from coupling with microfluidic technology. We also summarize recent efforts on developing microfluidic technology for genomic, transcriptomic, and epigenomic studies, with emphasis on single cell analysis. We envision rapid growth in these directions, driven by the needs for testing scarce primary cell samples from patients in the context of precision medicine. PMID:28396707

  4. Implications of genome-wide association studies in cancer therapeutics

    PubMed Central

    Patel, Jai N; McLeod, Howard L; Innocenti, Federico

    2013-01-01

    Genome wide association studies (GWAS) provide an agnostic approach to identifying potential genetic variants associated with disease susceptibility, prognosis of survival and/or predictive of drug response. Although these techniques are costly and interpretation of study results is challenging, they do allow for a more unbiased interrogation of the entire genome, resulting in the discovery of novel genes and understanding of novel biological associations. This review will focus on the implications of GWAS in cancer therapy, in particular germ-line mutations, including findings from major GWAS which have identified predictive genetic loci for clinical outcome and/or toxicity. Lessons and challenges in cancer GWAS are also discussed, including the need for functional analysis and replication, as well as future perspectives for biological and clinical utility. Given the large heterogeneity in response to cancer therapeutics, novel methods of identifying mechanisms and biology of variable drug response and ultimately treatment individualization will be indispensable. PMID:23701381

  5. High-resolution genome-wide mapping of histone modifications.

    PubMed

    Roh, Tae-young; Ngau, Wing Chi; Cui, Kairong; Landsman, David; Zhao, Keji

    2004-08-01

    The expression patterns of eukaryotic genomes are controlled by their chromatin structure, consisting of nucleosome subunits in which DNA of approximately 146 bp is wrapped around a core of 8 histone molecules. Post-translational histone modifications play an essential role in modifying chromatin structure. Here we apply a combination of SAGE and chromatin immunoprecipitation (ChIP) protocols to determine the distribution of hyperacetylated histones H3 and H4 in the Saccharomyces cerevisiae genome. We call this approach genome-wide mapping technique (GMAT). Using GMAT, we find that the highest acetylation levels are detected in the 5' end of a gene's coding region, but not in the promoter. Furthermore, we show that the histone acetyltransferase, GCN5p, regulates H3 acetylation in the promoter and 5' end of the coding regions. These findings indicate that GMAT should find valuable applications in mapping target sites of chromatin-modifying enzymes.

  6. Genome-wide measurement of RNA folding energies.

    PubMed

    Wan, Yue; Qu, Kun; Ouyang, Zhengqing; Kertesz, Michael; Li, Jun; Tibshirani, Robert; Makino, Debora L; Nutter, Robert C; Segal, Eran; Chang, Howard Y

    2012-10-26

    RNA structural transitions are important in the function and regulation of RNAs. Here, we reveal a layer of transcriptome organization in the form of RNA folding energies. By probing yeast RNA structures at different temperatures, we obtained relative melting temperatures (Tm) for RNA structures in over 4000 transcripts. Specific signatures of RNA Tm demarcated the polarity of mRNA open reading frames and highlighted numerous candidate regulatory RNA motifs in 3' untranslated regions. RNA Tm distinguished noncoding versus coding RNAs and identified mRNAs with distinct cellular functions. We identified thousands of putative RNA thermometers, and their presence is predictive of the pattern of RNA decay in vivo during heat shock. The exosome complex recognizes unpaired bases during heat shock to degrade these RNAs, coupling intrinsic structural stabilities to gene regulation. Thus, genome-wide structural dynamics of RNA can parse functional elements of the transcriptome and reveal diverse biological insights.

  7. Genome-wide studies of telomere biology in budding yeast

    PubMed Central

    Harari, Yaniv; Kupiec, Martin

    2014-01-01

    Telomeres are specialized DNA-protein structures at the ends of eukaryotic chromosomes. Telomeres are essential for chromosomal stability and integrity, as they prevent chromosome ends from being recognized as double strand breaks. In rapidly proliferating cells, telomeric DNA is synthesized by the enzyme telomerase, which copies a short template sequence within its own RNA moiety, thus helping to solve the “end-replication problem”, in which information is lost at the ends of chromosomes with each DNA replication cycle. The basic mechanisms of telomere length, structure and function maintenance are conserved among eukaryotes. Studies in the yeast Saccharomyces cerevisiae have been instrumental in deciphering the basic aspects of telomere biology. In the last decade, technical advances, such as the availability of mutant collections, have allowed carrying out systematic genome-wide screens for mutants affecting various aspects of telomere biology. In this review we summarize these efforts, and the insights that this Systems Biology approach has produced so far.

  8. The utility of genome-wide association studies in hepatology.

    PubMed

    Karlsen, Tom H; Melum, Espen; Franke, Andre

    2010-05-01

    Over the last 4 years, more than 450 genome-wide association studies (GWAS) have been successfully performed in a variety of human traits, of which approximately 2% relates to the field of hepatology. Whereas the many robust susceptibility gene findings have provided insight into fundamental physiological aspects of the phenotypes that have been studied, the widespread application has also revealed important limitations of the GWAS design. This review aims to systematically summarize both the strengths and the weaknesses of GWAS, as well as underscore important experiences made in model diseases outside the field of hepatology. By reviewing the GWAS performed in hepatology so far on this broader background, extensions and guidelines for the rational application of the study design in hepatology are proposed.

  9. Implications of genome-wide association studies in cancer therapeutics.

    PubMed

    Patel, Jai N; McLeod, Howard L; Innocenti, Federico

    2013-09-01

    Genome wide association studies (GWAS) provide an agnostic approach to identifying potential genetic variants associated with disease susceptibility, prognosis of survival and/or predictive of drug response. Although these techniques are costly and interpretation of study results is challenging, they do allow for a more unbiased interrogation of the entire genome, resulting in the discovery of novel genes and understanding of novel biological associations. This review will focus on the implications of GWAS in cancer therapy, in particular germ-line mutations, including findings from major GWAS which have identified predictive genetic loci for clinical outcome and/or toxicity. Lessons and challenges in cancer GWAS are also discussed, including the need for functional analysis and replication, as well as future perspectives for biological and clinical utility. Given the large heterogeneity in response to cancer therapeutics, novel methods of identifying mechanisms and biology of variable drug response and ultimately treatment individualization will be indispensable. © 2013 The British Pharmacological Society.

  10. Bioinformatics challenges in genome-wide association studies (GWAS).

    PubMed

    De, Rishika; Bush, William S; Moore, Jason H

    2014-01-01

    Genome-wide association studies (GWAS) are a powerful tool for investigators to examine the human genome to detect genetic risk factors, reveal the genetic architecture of diseases and open up new opportunities for treatment and prevention. However, despite its successes, GWAS have not been able to identify genetic loci that are effective classifiers of disease, limiting their value for genetic testing. This chapter highlights the challenges that lie ahead for GWAS in better identifying disease risk predictors, and how we may address them. In this regard, we review basic concepts regarding GWAS, the technologies used for capturing genetic variation, the missing heritability problem, the need for efficient study design especially for replication efforts, reducing the bias introduced into a dataset, and how to utilize new resources available, such as electronic medical records. We also look to what lies ahead for the field, and the approaches that can be taken to realize the full potential of GWAS.

  11. Quality control for genome-wide association studies.

    PubMed

    Gondro, Cedric; Lee, Seung Hwan; Lee, Hak Kyo; Porto-Neto, Laercio R

    2013-01-01

    This chapter overviews the quality control (QC) issues for SNP-based genotyping methods used in genome-wide association studies. The main metrics for evaluating the quality of the genotypes are discussed followed by a worked out example of QC pipeline starting with raw data and finishing with a fully filtered dataset ready for downstream analysis. The emphasis is on automation of data storage, filtering, and manipulation to ensure data integrity throughput the process and on how to extract a global summary from these high dimensional datasets to allow better-informed downstream analytical decisions. All examples will be run using the R statistical programming language followed by a practical example using a fully automated QC pipeline for the Illumina platform.

  12. Ultrafast laser nanosurgery in microfluidics for genome-wide screenings

    PubMed Central

    Ben-Yakar, Adela; Bourgeois, Frederic

    2009-01-01

    Summary The use of ultrafast laser pulses in surgery has allowed for unprecedented precision with minimal collateral damage to surrounding tissues. For these reasons, ultrafast laser nanosurgery, as an injury model, has gained tremendous momentum in experimental biology ranging from in-vitro manipulations of subcellular structures to in-vivo studies in whole living organisms. For example, femtosecond laser nanosurgery on such model organism as the nematode Caenorhabditis elegans (C. elegans) has opened new opportunities for in-vivo nerve regeneration studies. Meanwhile, the development of novel microfluidic devices has brought the control in experimental environment to the level required for precise nanosurgery in various animal models. Merging microfluidics and laser nanosurgery has recently improved the specificities and increased the speed of laser surgeries enabling fast genome-wide screenings that can more readily decode the genetic map of various biological processes. PMID:19278850

  13. Genome-wide association studies in pharmacogenomics of antidepressants.

    PubMed

    Lin, Eugene; Lane, Hsien-Yuan

    2015-01-01

    Major depressive disorder (MDD) is one of the most common psychiatric disorders worldwide. Doctors must prescribe antidepressants based on educated guesses due to the fact that it is unmanageable to predict the effectiveness of any particular antidepressant in an individual patient. With the recent advent of scientific research, the genome-wide association study (GWAS) is extensively employed to analyze hundreds of thousands of single nucleotide polymorphisms by high-throughput genotyping technologies. In addition to the candidate-gene approach, the GWAS approach has recently been utilized to investigate the determinants of antidepressant response to therapy. In this study, we reviewed GWAS studies, their limitations and future directions with respect to the pharmacogenomics of antidepressants in MDD.

  14. Genome-wide association study of drought-related resistance traits in Aegilops tauschii

    PubMed Central

    Qin, Peng; Lin, Yu; Hu, Yaodong; Liu, Kun; Mao, Shuangshuang; Li, Zhanyi; Wang, Jirui; Liu, Yaxi; Wei, Yuming; Zheng, Youliang

    2016-01-01

    Abstract The D-genome progenitor of wheat (Triticum aestivum), Aegilops tauschii, possesses numerous genes for resistance to abiotic stresses, including drought. Therefore, information on the genetic architecture of A. tauschii can aid the development of drought-resistant wheat varieties. Here, we evaluated 13 traits in 373 A. tauschii accessions grown under normal and polyethylene glycol-simulated drought stress conditions and performed a genome-wide association study using 7,185 single nucleotide polymorphism (SNP) markers. We identified 208 and 28 SNPs associated with all traits using the general linear model and mixed linear model, respectively, while both models detected 25 significant SNPs with genome-wide distribution. Public database searches revealed several candidate/flanking genes related to drought resistance that were grouped into three categories according to the type of encoded protein (enzyme, storage protein, and drought-induced protein). This study provided essential information for SNPs and genes related to drought resistance in A. tauschii and wheat, and represents a foundation for breeding drought-resistant wheat cultivars using marker-assisted selection. PMID:27560650

  15. Genome-wide characterization of microsatellites in Triticeae species: abundance, distribution and evolution

    PubMed Central

    Deng, Pingchuan; Wang, Meng; Feng, Kewei; Cui, Licao; Tong, Wei; Song, Weining; Nie, Xiaojun

    2016-01-01

    Microsatellites are an important constituent of plant genome and distributed across entire genome. In this study, genome-wide analysis of microsatellites in 8 Triticeae species and 9 model plants revealed that microsatellite characteristics were similar among the Triticeae species. Furthermore, genome-wide microsatellite markers were designed in wheat and then used to analyze the evolutionary relationship of wheat and other Triticeae species. Results displayed that Aegilops tauschii was found to be the closest species to Triticum aestivum, followed by Triticum urartu, Triticum turgidum and Aegilops speltoides, while Triticum monococcum, Aegilops sharonensis and Hordeum vulgare showed a relatively lower PCR amplification effectivity. Additionally, a significantly higher PCR amplification effectivity was found in chromosomes at the same subgenome than its homoeologous when these markers were subjected to search against different chromosomes in wheat. After a rigorous screening process, a total of 20,666 markers showed high amplification and polymorphic potential in wheat and its relatives, which were integrated with the public available wheat markers and then anchored to the genome of wheat (CS). This study not only provided the useful resource for SSR markers development in Triticeae species, but also shed light on the evolution of polyploid wheat from the perspective of microsatellites. PMID:27561724

  16. Comparison of genome-wide selection strategies to identify furfural tolerance genes in Escherichia coli.

    PubMed

    Glebes, Tirzah Y; Sandoval, Nicholas R; Gillis, Jacob H; Gill, Ryan T

    2015-01-01

    Engineering both feedstock and product tolerance is important for transitioning towards next-generation biofuels derived from renewable sources. Tolerance to chemical inhibitors typically results in complex phenotypes, for which multiple genetic changes must often be made to confer tolerance. Here, we performed a genome-wide search for furfural-tolerant alleles using the TRackable Multiplex Recombineering (TRMR) method (Warner et al. (2010), Nature Biotechnology), which uses chromosomally integrated mutations directed towards increased or decreased expression of virtually every gene in Escherichia coli. We employed various growth selection strategies to assess the role of selection design towards growth enrichments. We also compared genes with increased fitness from our TRMR selection to those from a previously reported genome-wide identification study of furfural tolerance genes using a plasmid-based genomic library approach (Glebes et al. (2014) PLOS ONE). In several cases, growth improvements were observed for the chromosomally integrated promoter/RBS mutations but not for the plasmid-based overexpression constructs. Through this assessment, four novel tolerance genes, ahpC, yhjH, rna, and dicA, were identified and confirmed for their effect on improving growth in the presence of furfural. © 2014 Wiley Periodicals, Inc.

  17. A genome-wide association study of anorexia nervosa

    PubMed Central

    Boraska, Vesna; Franklin, Christopher S; Floyd, James AB; Thornton, Laura M; Huckins, Laura M; Southam, Lorraine; Rayner, N William; Tachmazidou, Ioanna; Klump, Kelly L; Treasure, Janet; Lewis, Cathryn M; Schmidt, Ulrike; Tozzi, Federica; Kiezebrink, Kirsty; Hebebrand, Johannes; Gorwood, Philip; Adan, Roger AH; Kas, Martien JH; Favaro, Angela; Santonastaso, Paolo; Fernández-Aranda, Fernando; Gratacos, Monica; Rybakowski, Filip; Dmitrzak-Weglarz, Monika; Kaprio, Jaakko; Keski-Rahkonen, Anna; Raevuori, Anu; Van Furth, Eric F; Landt, Margarita CT Slof-Op t; Hudson, James I; Reichborn-Kjennerud, Ted; Knudsen, Gun Peggy S; Monteleone, Palmiero; Kaplan, Allan S; Karwautz, Andreas; Hakonarson, Hakon; Berrettini, Wade H; Guo, Yiran; Li, Dong; Schork, Nicholas J.; Komaki, Gen; Ando, Tetsuya; Inoko, Hidetoshi; Esko, Tõnu; Fischer, Krista; Männik, Katrin; Metspalu, Andres; Baker, Jessica H; Cone, Roger D; Dackor, Jennifer; DeSocio, Janiece E; Hilliard, Christopher E; O'Toole, Julie K; Pantel, Jacques; Szatkiewicz, Jin P; Taico, Chrysecolla; Zerwas, Stephanie; Trace, Sara E; Davis, Oliver SP; Helder, Sietske; Bühren, Katharina; Burghardt, Roland; de Zwaan, Martina; Egberts, Karin; Ehrlich, Stefan; Herpertz-Dahlmann, Beate; Herzog, Wolfgang; Imgart, Hartmut; Scherag, André; Scherag, Susann; Zipfel, Stephan; Boni, Claudette; Ramoz, Nicolas; Versini, Audrey; Brandys, Marek K; Danner, Unna N; de Kovel, Carolien; Hendriks, Judith; Koeleman, Bobby PC; Ophoff, Roel A; Strengman, Eric; van Elburg, Annemarie A; Bruson, Alice; Clementi, Maurizio; Degortes, Daniela; Forzan, Monica; Tenconi, Elena; Docampo, Elisa; Escaramís, Geòrgia; Jiménez-Murcia, Susana; Lissowska, Jolanta; Rajewski, Andrzej; Szeszenia-Dabrowska, Neonila; Slopien, Agnieszka; Hauser, Joanna; Karhunen, Leila; Meulenbelt, Ingrid; Slagboom, P Eline; Tortorella, Alfonso; Maj, Mario; Dedoussis, George; Dikeos, Dimitris; Gonidakis, Fragiskos; Tziouvas, Konstantinos; Tsitsika, Artemis; Papezova, Hana; Slachtova, Lenka; Martaskova, Debora; Kennedy, James L.; Levitan, Robert D.; Yilmaz, Zeynep; Huemer, Julia; Koubek, Doris; Merl, Elisabeth; Wagner, Gudrun; Lichtenstein, Paul; Breen, Gerome; Cohen-Woods, Sarah; Farmer, Anne; McGuffin, Peter; Cichon, Sven; Giegling, Ina; Herms, Stefan; Rujescu, Dan; Schreiber, Stefan; Wichmann, H-Erich; Dina, Christian; Sladek, Rob; Gambaro, Giovanni; Soranzo, Nicole; Julia, Antonio; Marsal, Sara; Rabionet, Raquel; Gaborieau, Valerie; Dick, Danielle M; Palotie, Aarno; Ripatti, Samuli; Widén, Elisabeth; Andreassen, Ole A; Espeseth, Thomas; Lundervold, Astri; Reinvang, Ivar; Steen, Vidar M; Le Hellard, Stephanie; Mattingsdal, Morten; Ntalla, Ioanna; Bencko, Vladimir; Foretova, Lenka; Janout, Vladimir; Navratilova, Marie; Gallinger, Steven; Pinto, Dalila; Scherer, Stephen; Aschauer, Harald; Carlberg, Laura; Schosser, Alexandra; Alfredsson, Lars; Ding, Bo; Klareskog, Lars; Padyukov, Leonid; Finan, Chris; Kalsi, Gursharan; Roberts, Marion; Logan, Darren W; Peltonen, Leena; Ritchie, Graham RS; Barrett, Jeffrey C; Estivill, Xavier; Hinney, Anke; Sullivan, Patrick F; Collier, David A; Zeggini, Eleftheria; Bulik, Cynthia M

    2015-01-01

    Anorexia nervosa (AN) is a complex and heritable eating disorder characterized by dangerously low body weight. Neither candidate gene studies nor an initial genome wide association study (GWAS) have yielded significant and replicated results. We performed a GWAS in 2,907 cases with AN from 14 countries (15 sites) and 14,860 ancestrally matched controls as part of the Genetic Consortium for AN (GCAN) and the Wellcome Trust Case Control Consortium 3 (WTCCC3). Individual association analyses were conducted in each stratum and meta-analyzed across all 15 discovery datasets. Seventy-six (72 independent) SNPs were taken forward for in silico (two datasets) or de novo (13 datasets) replication genotyping in 2,677 independent AN cases and 8,629 European ancestry controls along with 458 AN cases and 421 controls from Japan. The final global meta-analysis across discovery and replication datasets comprised 5,551 AN cases and 21,080 controls. AN subtype analyses (1,606 AN restricting; 1,445 AN binge-purge) were performed. No findings reached genome-wide significance. Two intronic variants were suggestively associated: rs9839776 (P=3.01×10-7) in SOX2OT and rs17030795 (P=5.84×10-6) in PPP3CA. Two additional signals were specific to Europeans: rs1523921 (P=5.76×10-6) between CUL3 and FAM124B and rs1886797 (P=8.05×10-6) near SPATA13. Comparing discovery to replication results, 76% of the effects were in the same direction, an observation highly unlikely to be due to chance (P=4×10-6), strongly suggesting that true findings exist but that our sample, the largest yet reported, was underpowered for their detection. The accrual of large genotyped AN case-control samples should be an immediate priority for the field. PMID:24514567

  18. Genome-Wide Expression Profiling of Complex Regional Pain Syndrome

    PubMed Central

    Jin, Eun-Heui; Zhang, Enji; Ko, Youngkwon; Sim, Woo Seog; Moon, Dong Eon; Yoon, Keon Jung; Hong, Jang Hee; Lee, Won Hyung

    2013-01-01

    Complex regional pain syndrome (CRPS) is a chronic, progressive, and devastating pain syndrome characterized by spontaneous pain, hyperalgesia, allodynia, altered skin temperature, and motor dysfunction. Although previous gene expression profiling studies have been conducted in animal pain models, there genome-wide expression profiling in the whole blood of CRPS patients has not been reported yet. Here, we successfully identified certain pain-related genes through genome-wide expression profiling in the blood from CRPS patients. We found that 80 genes were differentially expressed between 4 CRPS patients (2 CRPS I and 2 CRPS II) and 5 controls (cut-off value: 1.5-fold change and p<0.05). Most of those genes were associated with signal transduction, developmental processes, cell structure and motility, and immunity and defense. The expression levels of major histocompatibility complex class I A subtype (HLA-A29.1), matrix metalloproteinase 9 (MMP9), alanine aminopeptidase N (ANPEP), l-histidine decarboxylase (HDC), granulocyte colony-stimulating factor 3 receptor (G-CSF3R), and signal transducer and activator of transcription 3 (STAT3) genes selected from the microarray were confirmed in 24 CRPS patients and 18 controls by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). We focused on the MMP9 gene that, by qRT-PCR, showed a statistically significant difference in expression in CRPS patients compared to controls with the highest relative fold change (