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Sample records for adult twin pairs

  1. Childhood infections and adult height in monozygotic twin pairs.

    PubMed

    Hwang, Amie E; Mack, Thomas M; Hamilton, Ann S; Gauderman, W James; Bernstein, Leslie; Cockburn, Myles G; Zadnick, John; Rand, Kristin A; Hopper, John L; Cozen, Wendy

    2013-08-15

    Adult height is determined by genetics and childhood nutrition, but childhood infections may also play a role. Monozygotic twins are genetically matched and offer an advantage when identifying environmental determinants. In 2005-2007, we examined the association of childhood infections with adult height in 140 height-discordant monozygotic twin pairs from the California Twin Program. To obtain information on childhood infections and growth, we interviewed the mothers of monozygotic twins who differed in self-reported adult height by at least 1-inch (2.5 cm). Within-pair differences in the relative frequency of childhood infections were highly correlated, especially within age groups. A conditional logistic regression analysis demonstrated that more reported episodes of febrile illness occurred in the twin with shorter stature (odds ratio = 2.00, 95% confidence interval: 1.18, 3.40). The association was strongest for differences in the relative frequency of infection during the toddler years (ages 1-5: odds ratio = 3.34, 95% confidence interval: 1.47, 7.59) and was similar when restricted to twin pairs of equal birth length. The association was not explained by differential nutritional status. Measures of childhood infection were associated with height difference in monozygotic twin pairs, independent of genome, birth length, and available measures of diet. PMID:23585330

  2. [Adult twins].

    PubMed

    Charlemaine, Christiane

    2006-12-31

    This paper explores the deep roots of closeness that twins share in their youngest age and their effect on their destiny at the adult age. Psychologists believe the bond between twins begins in utero and develops throughout the twins' lives. The four patterns of twinship described show that the twin bond is determined by the quality of parenting that twins receive in their infancy and early childhood. Common problems of adult twins bring about difficulties to adapt in a non-twin world. The nature versus nurture controversy has taken on new life focusing on inter-twin differences and the importance of parent-child interaction as fundamental to the growth and development of personality. PMID:17352324

  3. One CNV Discordance in NRXN1 Observed Upon Genome-wide Screening in 38 Pairs of Adult Healthy Monozygotic Twins.

    PubMed

    Magnusson, Patrik K E; Lee, Donghwan; Chen, Xu; Szatkiewicz, Jin; Pramana, Setia; Teo, Shumei; Sullivan, Patrick F; Feuk, Lars; Pawitan, Yudi

    2016-04-01

    Monozygotic (MZ) twins stem from the same single fertilized egg and therefore share all their inherited genetic variation. This is one of the unequivocal facts on which genetic epidemiology and twin studies are based. To what extent this also implies that MZ twins share genotypes in adult tissues is not precisely established, but a common pragmatic assumption is that MZ twins are 100% genetically identical also in adult tissues. During the past decade, this view has been challenged by several reports, with observations of differences in post-zygotic copy number variations (CNVs) between members of the same MZ pair. In this study, we performed a systematic search for differences of CNVs within 38 adult MZ pairs who had been misclassified as dizygotic (DZ) twins by questionnaire-based assessment. Initial scoring by PennCNV suggested a total of 967 CNV discordances. The within-pair correlation in number of CNVs detected was strongly dependent on confidence score filtering and reached a plateau of r = 0.8 when restricting to CNVs detected with confidence score larger than 50. The top-ranked discordances were subsequently selected for validation by quantitative polymerase chain reaction (qPCR), from which one single ~120kb deletion in NRXN1 on chromosome 2 (bp 51017111-51136802) was validated. Despite involving an exon, no sign of cognitive/mental consequences was apparent in the affected twin pair, potentially reflecting limited or lack of expression of the transcripts containing this exon in nerve/brain. PMID:26899349

  4. Intra-Monozygotic Twin Pair Discordance and Longitudinal Variation of Whole-Genome Scale DNA Methylation in Adults

    PubMed Central

    Zhang, Su-Hua; Chen, Jinzhong; Lu, Daru; Shen, Min; Li, Chengtao

    2015-01-01

    Monozygotic twins share identical genomic DNA and are indistinguishable using conventional genetic markers. Increasing evidence indicates that monozygotic twins are epigenetically distinct, suggesting that a comparison between DNA methylation patterns might be useful to approach this forensic problem. However, the extent of epigenetic discordance between healthy adult monozygotic twins and the stability of CpG loci within the same individual over a short time span at the whole-genome scale are not well understood. Here, we used Infinium HumanMethylation450 Beadchips to compare DNA methylation profiles using blood collected from 10 pairs of monozygotic twins and 8 individuals sampled at 0, 3, 6, and 9 months. Using an effective and unbiased method for calling differentially methylated (DM) CpG sites, we showed that 0.087%–1.530% of the CpG sites exhibit differential methylation in monozygotic twin pairs. We further demonstrated that, on whole-genome level, there has been no significant epigenetic drift within the same individuals for up to 9 months, including one monozygotic twin pair. However, we did identify a subset of CpG sites that vary in DNA methylation over the 9-month period. The magnitude of the intra-pair or longitudinal methylation discordance of the CpG sites inside the CpG islands is greater than those outside the CpG islands. The CpG sites located on shores appear to be more suitable for distinguishing between MZ twins. PMID:26248206

  5. Intra-Monozygotic Twin Pair Discordance and Longitudinal Variation of Whole-Genome Scale DNA Methylation in Adults.

    PubMed

    Zhang, Na; Zhao, Shumin; Zhang, Su-Hua; Chen, Jinzhong; Lu, Daru; Shen, Min; Li, Chengtao

    2015-01-01

    Monozygotic twins share identical genomic DNA and are indistinguishable using conventional genetic markers. Increasing evidence indicates that monozygotic twins are epigenetically distinct, suggesting that a comparison between DNA methylation patterns might be useful to approach this forensic problem. However, the extent of epigenetic discordance between healthy adult monozygotic twins and the stability of CpG loci within the same individual over a short time span at the whole-genome scale are not well understood. Here, we used Infinium HumanMethylation450 Beadchips to compare DNA methylation profiles using blood collected from 10 pairs of monozygotic twins and 8 individuals sampled at 0, 3, 6, and 9 months. Using an effective and unbiased method for calling differentially methylated (DM) CpG sites, we showed that 0.087%-1.530% of the CpG sites exhibit differential methylation in monozygotic twin pairs. We further demonstrated that, on whole-genome level, there has been no significant epigenetic drift within the same individuals for up to 9 months, including one monozygotic twin pair. However, we did identify a subset of CpG sites that vary in DNA methylation over the 9-month period. The magnitude of the intra-pair or longitudinal methylation discordance of the CpG sites inside the CpG islands is greater than those outside the CpG islands. The CpG sites located on shores appear to be more suitable for distinguishing between MZ twins. PMID:26248206

  6. Modeling genetic and environmental influences in the etiology of conduct disorder: a study of 2,682 adult twin pairs.

    PubMed

    Slutske, W S; Heath, A C; Dinwiddie, S H; Madden, P A; Bucholz, K K; Dunne, M P; Statham, D J; Martin, N G

    1997-05-01

    The etiology of conduct disorder (CD) was examined retrospectively in a sample of 2,682 male, female, and unlike-sex adult twin pairs from the community-based Australian Twin Register. Model-fitting analyses indicated a substantial genetic influence on risk for CD, accounting for 71% of the variance (95% confidence interval [CI] = 32-79%). There was not a statistically significant effect of the shared environment in the best-fitting model of CD, but a modest effect of the shared environment on the risk for CD could not be rejected (95% CI = 0-32%). The magnitude of genetic and environmental influences for CD liability did not vary significantly for boys and girls, and the specific genetic and environmental mechanisms important for the development of CD appeared to be largely the same for both sexes. The fit of a multiple-threshold model raises the possibility that CD may not necessarily be a discrete entity but rather an extreme of the normal variation in conduct-disordered behavior found in the general population. PMID:9131847

  7. A Comparison of Anthropometric, Metabolic, and Reproductive Characteristics of Young Adult Women from Opposite-Sex and Same-Sex Twin Pairs

    PubMed Central

    Korsoff, Pirkko; Bogl, Leonie H.; Korhonen, Päivi; Kangas, Antti J.; Soininen, Pasi; Ala-Korpela, Mika; Rose, Richard J.; Kaaja, Risto; Kaprio, Jaakko

    2014-01-01

    Background: Prenatal exposure to androgens has been linked to masculinization of several traits. We aimed to determine whether putative female intra-uterine exposure to androgens influences anthropometric, metabolic, and reproductive parameters using a twin design. Methods: Two cohorts of Finnish twins born in 1975–1979 and 1983–1987 formed the basis for the longitudinal FinnTwin16 (FT16) and FinnTwin12 (FT12) studies. Self-reported anthropometric characteristics, disease status, and reproductive history were compared between 679 same-sex (SS) and 789 opposite-sex (OS) female twins (mean age ± SD: 34 ± 1.1) from the wave 5 of data collection in FT16. Serum lipid and lipoprotein subclass concentrations measured by nuclear magnetic resonance spectroscopy were compared in 226 SS and 169 OS female twins (mean age ± SD: 24 ± 2.1) from the wave 4 of data collection in FT12 and FT16. Results: Anthropometric measures, the prevalence of hypertension and diabetes mellitus type 2 did not differ significantly between females from SS and OS twin pairs at age 34. Similarly, the prevalence of infertility, age at first pregnancy and number of induced and spontaneous abortions did not differ significantly between these two groups of women. The serum lipid and lipoprotein profile did not differ between females from SS and OS twins at age 24. Conclusion: We found no evidence that androgen overexposure of the female fetus affects obesity, metabolic profile, or reproductive health in young adult females. However, these results do not exclude the possibility that prenatal androgen exposure in females could be adversely associated with these phenotypes later in life. PMID:24639667

  8. CNV Concordance in 1,097 MZ Twin Pairs.

    PubMed

    Abdellaoui, Abdel; Ehli, Erik A; Hottenga, Jouke-Jan; Weber, Zachary; Mbarek, Hamdi; Willemsen, Gonneke; van Beijsterveldt, Toos; Brooks, Andrew; Hudziak, Jim J; Sullivan, Patrick F; de Geus, Eco J; Davies, Gareth E; Boomsma, Dorret I

    2015-02-01

    Monozygotic (MZ) twins are genetically identical at conception, making them informative subjects for studies on somatic mutations. Copy number variants (CNVs) are responsible for a substantial part of genetic variation, have relatively high mutation rates, and are likely to be involved in phenotypic variation. We conducted a genome-wide survey for post-twinning de novo CNVs in 1,097 MZ twin pairs. Comparisons between MZ twins were made by CNVs measured in DNA from blood or buccal epithelium with the Affymetrix 6.0 microarray and two calling algorithms. In addition, CNV concordance rates were compared between the different sources of DNA, and gene-enrichment association analyses were conducted for thought problems (TP) and attention problems (AP) using CNVs concordant within MZ pairs. We found a total of 153 putative post-twinning de novo CNVs >100 kb, of which the majority resided in 15q11.2. Based on the discordance of raw intensity signals a selection was made of 20 de novo CNVs for a qPCR validation experiments. Two out of 20 post-twinning de novo CNVs were validated with qPCR in the same twin pair. The 13-year-old MZ twin pair that showed two discordances in CN in 15q11.2 in their buccal DNA did not show large phenotypic differences. From the remaining 18 putative de novo CNVs, 17 were deletions or duplications that were concordant within MZ twin pairs. Concordance rates within twin pairs of CNV calls with CN ≠ 2 were ~80%. Buccal epithelium-derived DNA showed a slightly but significantly higher concordance rate, and blood-derived DNA showed significantly more concordant CNVs per twin pair. The gene-enrichment analyses on concordant CNVs showed no significant associations between CNVs overlapping with genes involved in neuronal processes and TP or AP after accounting for the source of DNA. PMID:25578775

  9. Hippocampal MRI volumetry in cognitively discordant monozygotic twin pairs

    PubMed Central

    Jarvenpaa, T; Laakso, M; Rossi, R; Koskenvuo, M; Kaprio, J; Raiha, I; Kurki, T; Laine, M; Frisoni, G; Rinne, J

    2004-01-01

    Objective: To investigate whether hippocampal atrophy, a proxy for incipient Alzheimer's disease, can be detected in non-demented monozygotic co-twins of demented twins by using volumetric magnetic resonance imaging (MRI). Methods: Seven pairs of monozygotic female twins discordant for cognitive function (mean (SD) age 75 (4) years), and 10 age and education matched healthy controls (seven women, three men; mean age 73 (3) years) were studied with volumetric MRI. Results: The mean normalised right hippocampal volume was 31% lower (p = 0.002) in the demented twins, and 6% lower (p = 0.45) in the non-demented twins than in the controls. In the left hippocampus, the mean normalised volume was 36% lower (p<0.001) in the demented twins, and 9% lower (p = 0.13) in the non-demented twins than in the controls. Conclusions: Significant hippocampal atrophy was detected in the demented twins compared with the controls. This is in line with previous imaging and pathological studies, with hippocampus showing the early changes in Alzheimer's disease. In the non-demented twins, only a minor, non-significant reduction was observed in the hippocampal volumes compared with the controls. This could reflect gene–environment interactions that have protected the non-demented twins longer than their demented co-twins and contributed to the relative preservation of their hippocampal volumes, or it could be a sign of preclinical Alzheimer's disease in the non-demented twins. PMID:14707319

  10. Mesial temporal lobe epilepsy with hippocampal sclerosis in two pairs of identical twins.

    PubMed

    Karatas, H; Dericioglu, N; Saygi, S

    2012-01-01

    The most common pathology in adult patients with temporal lobe epilepsy is hippocampal sclerosis (HS), the etiology of which is not clear. There is a conflicting evidence in literature regarding whether HS is genetic or acquired. Twin studies can help to clarify the mechanisms of HS, but limited numbers of twins have been studied. We describe two monozygotic pairs, in whom the affected twin had mesial temporal lobe epilepsy and HS. The unaffected twin remained seizure free on long-term follow-up. HS was confirmed pathologically in one of the affected twins. Our data and other limited twin studies indicate that HS occurs as a consequence of prolonged repeated seizures or other events during childhood. In other words, some acquired factors may be more important than genetic ones in the etiology of HS (Fig. 2, Ref. 16). PMID:22794520

  11. Gut microbiomes of Malawian twin pairs discordant for kwashiorkor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Kwashiorkor, an enigmatic form of severe acute malnutrition, is the consequence of inadequate nutrient intake plus additional environmental insults. To investigate the role of the gut microbiome, we studied 317 Malawian twin pairs during the first 3 years of life. During this time, half of the twin ...

  12. Biliary lipid composition in monozygotic and dizygotic pairs of twins.

    PubMed Central

    Antero Kesäniemi, Y; Koskenvuo, M; Vuoristo, M; Miettinen, T A

    1989-01-01

    The relative contribution of genetic factors to biliary and serum lipid composition was studied in 17 monozygotic and 18 dizygotic middle aged male pairs of twins. Cholesterol precursors, squalene and Methylated sterols which reflect the activity of cholesterol synthesis were also measured. Pairwise intraclass correlations were determined for monozygotic and dizygotic twin pairs and heritability estimates were calculated. Molar % of biliary cholesterol and percentage distribution of biliary cholic acid and particularly deoxycholic acid showed significant pairwise correlations within the monozygotic but not the dizygotic pairs. Similar correlations were found for total biliary methylsterols and of the methylsterol subfractions for the two methostenols but not for squalene, lanosterol and dimethylsterols. In serum, the precursor sterols, but not squalene, showed even higher pairwise correlations in the monozygotic twins than the corresponding precursors in bile. Molar per cent of bile acids and phospholipids and cholesterol saturation index were not correlated significantly in either twin pairs, but the pairwise correlations tended to be higher in the monozygotic than in the dizygotic pairs. Gall stones were found in seven monozygotic and three dizygotic subjects. Two monozygotic twin pairs were concordant for gall stones; all the dizygotic pairs were discordant. Overall, these data suggest that molar percentage of biliary cholesterol, bile acid composition, cholesterol synthesis, bile cholesterol saturation, and gall stone formation may be under a significant genetic control. PMID:2612989

  13. Proton MRS in twin pairs discordant for schizophrenia.

    PubMed

    Lutkenhoff, E S; van Erp, T G; Thomas, M A; Therman, S; Manninen, M; Huttunen, M O; Kaprio, J; Lönnqvist, J; O'Neill, J; Cannon, T D

    2010-03-01

    Proton magnetic resonance spectroscopy ((1)H MRS) neurometabolite abnormalities have been detected widely in subjects with and at risk for schizophrenia. We hypothesized that such abnormalities would be present both in patients with schizophrenia and in their unaffected twin siblings. We acquired magnetic resonance spectra (TR/TE=3000/30 ms) at voxels in the mesial prefrontal gray matter, left prefrontal white matter and left hippocampus in 14 twin pairs discordant for schizophrenia (2 monozygotic, 12 dizygotic), 13 healthy twin pairs (4 monozygotic, 9 dizygotic) and 1 additional unaffected co-twin of a schizophrenia proband. In the mesial prefrontal gray matter voxel, N-acetylaspartate (NAA), creatine+phosphocreatine (Cr), glycerophosphocholine+phosphocholine (Cho) and myo-inositol (mI) did not differ significantly between patients with schizophrenia, their unaffected co-twins or healthy controls. However, glutamate (Glu) was significantly lower in patients with schizophrenia (31%, percent difference) and unaffected co-twins (21%) than in healthy controls (collapsed across twin pairs). In the left hippocampus voxel, levels of NAA (23%), Cr (22%) and Cho (36%) were higher in schizophrenia patients compared with controls. Hippocampal NAA (25%), Cr (22%) and Cho (37%) were also significantly higher in patients than in their unaffected co-twins. Region-to-region differences in metabolite levels were also notable within all three diagnosis groups. These findings suggest that (1)H MRS neurometabolite abnormalities are present not only in patients with schizophrenia, but also in their unaffected co-twins. Thus, reduced mesial prefrontal cortical Glu and elevated hippocampal NAA, Cr and Cho may represent trait markers of schizophrenia risk and, when exacerbated, state markers of schizophrenia itself. PMID:18645571

  14. Twins: within-pair similarity on Bayley's Infant Behavior Record.

    PubMed

    Matheny, A P; Dolan, A B; Wilson, R S

    1976-06-01

    Summary scores for behaviors rated on Bayley's Infant Behavior Record were obtained by summing sequential ratings for same-sex twins participating in a longitudinal study. The first year scores were based on visits made at 3, 6, 9, and 12 months, by 55 identical and 27 fraternal pairs; the second year scores were based on visits at 18, 24, and 30 months, by 47 identical and 27 fraternal pairs. During the first year, within-pair correlations for almost all behaviors were stronger for identical than for fraternal pairs; in the second year, within-pair correlations for identical twins were similar to those of fraternal twins except for the more cognitive behaviors. Composite scores were calculated for two behavioral clusters--one composed of behaviors related to Primary Cognition, and the other composed of behaviors related to Extraversion. Within-pair correlations were higher for identical than for fraternal twins in both the first and second years, indicating stronger and more consistent genetic influences on the more cognitive behaviors. PMID:945328

  15. [Refsum syndrome in a pair of monozygotic twins].

    PubMed

    Kohnen, S; Hammerstein, W

    1993-10-01

    We report the case of a pair of twins with the ophthalmological and functional findings of Refsum syndrome. The twins were monozygotic twin brothers whose ophthalmological symptoms were noticed when they were in their forties. The diagnosis in the first brother led to a search for findings in the second. It was possible to attribute the non-specific subjective complaints to this as yet unknown syndrome. No causal therapy can be offered the patients. However, knowledge of the biochemical basis of the disease makes it possible to treat it by means of diet. In patients with retinopathia pigmentosa, an attempt should be made to identify Refsum syndrome if neurological symptoms are found in addition.

  16. Gut microbiomes of Malawian twin pairs discordant for kwashiorkor.

    PubMed

    Smith, Michelle I; Yatsunenko, Tanya; Manary, Mark J; Trehan, Indi; Mkakosya, Rajhab; Cheng, Jiye; Kau, Andrew L; Rich, Stephen S; Concannon, Patrick; Mychaleckyj, Josyf C; Liu, Jie; Houpt, Eric; Li, Jia V; Holmes, Elaine; Nicholson, Jeremy; Knights, Dan; Ursell, Luke K; Knight, Rob; Gordon, Jeffrey I

    2013-02-01

    Kwashiorkor, an enigmatic form of severe acute malnutrition, is the consequence of inadequate nutrient intake plus additional environmental insults. To investigate the role of the gut microbiome, we studied 317 Malawian twin pairs during the first 3 years of life. During this time, half of the twin pairs remained well nourished, whereas 43% became discordant, and 7% manifested concordance for acute malnutrition. Both children in twin pairs discordant for kwashiorkor were treated with a peanut-based, ready-to-use therapeutic food (RUTF). Time-series metagenomic studies revealed that RUTF produced a transient maturation of metabolic functions in kwashiorkor gut microbiomes that regressed when administration of RUTF was stopped. Previously frozen fecal communities from several discordant pairs were each transplanted into gnotobiotic mice. The combination of Malawian diet and kwashiorkor microbiome produced marked weight loss in recipient mice, accompanied by perturbations in amino acid, carbohydrate, and intermediary metabolism that were only transiently ameliorated with RUTF. These findings implicate the gut microbiome as a causal factor in kwashiorkor.

  17. Gut microbiomes of Malawian twin pairs discordant for kwashiorkor

    PubMed Central

    Smith, Michelle I.; Yatsunenko, Tanya; Manary, Mark J.; Trehan, Indi; Mkakosya, Rajhab; Cheng, Jiye; Kau, Andrew L.; Rich, Stephen S.; Concannon, Patrick; Mychaleckyj, Josyf C.; Liu, Jie; Houpt, Eric; Li, Jia V.; Holmes, Elaine; Nicholson, Jeremy; Knights, Dan; Ursell, Luke K.; Knight, Rob; Gordon, Jeffrey I.

    2013-01-01

    Kwashiorkor, an enigmatic form of severe acute malnutrition, is the consequence of inadequate nutrient intake plus additional environmental insults. To investigate the role of the gut microbiome, we studied 317 Malawian twin pairs during the first 3 years of life. During this time, half of the twin pairs remained well-nourished, while 43% became discordant and 7% manifested concordance for acute malnutrition. Both children in twin pairs discordant for kwashiorkor were treated with a peanut-based, ready-to-use therapeutic food (RUTF). Time-series metagenomic studies revealed that RUTF produced a transient maturation of metabolic functions in kwashiorkor microbiomes that regressed when RUTF was stopped. Previously frozen fecal communities from several discordant pairs were each transplanted into gnotobiotic mice. The combination of Malawian diet and kwashiorkor microbiome produced marked weight loss in recipient mice, accompanied by perturbations in amino acid, carbohydrate and intermediary metabolism that were only transiently ameliorated with RUTF. These findings implicate the gut microbiome as a causal factor in kwashiorkor. PMID:23363771

  18. The 2016 Satellite Meeting of the International Society of Twin Studies: An Overview/Tribute to Irving I. Gottesman/Research: MZ Twinning After Single Embryo Transfer; Twin Study of Mononucleosis; Cerebral Injury After Twin-To-Twin Transfusion Syndrome Surgery/Human Interest: Sixteen Twin Pairs Born in a Single Hospital; Death of an Identical Twin Playwright; Twin Themes in Advertising; Conjoined Twins Separated in Saudi Arabia; Murder of One Twin By Her Co-Twin Disproved.

    PubMed

    Segal, Nancy L

    2016-10-01

    The 2016 Satellite Meeting of the International Society of Twin Studies took place on June 20 in Brisbane, Australia. The host institution was the QIMR Berghofer Medical Research Institute. An overview of selected presentations and activities is provided. This synopsis is followed by a brief tribute to the recent passing of our esteemed colleague, Dr Irving I. Gottesman. Next, there are summaries of research on monozygotic twinning after single embryo transfer, a twin study of mononucleosis susceptibility, cerebral injury following twin-to-twin transfusion syndrome surgery, and a correction and clarification regarding an article by Segal (2016) on the Brazilian Twin Registry. Human interest articles cover a hospital whose 2015 newborns included 16 pairs of twins born in 1 month, the death of an identical twin playwright, twin themes in advertising, conjoined twins separated in Saudi Arabia, and the dismissed charges of the murder of one twin by her co-twin.

  19. The 2016 Satellite Meeting of the International Society of Twin Studies: An Overview/Tribute to Irving I. Gottesman/Research: MZ Twinning After Single Embryo Transfer; Twin Study of Mononucleosis; Cerebral Injury After Twin-To-Twin Transfusion Syndrome Surgery/Human Interest: Sixteen Twin Pairs Born in a Single Hospital; Death of an Identical Twin Playwright; Twin Themes in Advertising; Conjoined Twins Separated in Saudi Arabia; Murder of One Twin By Her Co-Twin Disproved.

    PubMed

    Segal, Nancy L

    2016-10-01

    The 2016 Satellite Meeting of the International Society of Twin Studies took place on June 20 in Brisbane, Australia. The host institution was the QIMR Berghofer Medical Research Institute. An overview of selected presentations and activities is provided. This synopsis is followed by a brief tribute to the recent passing of our esteemed colleague, Dr Irving I. Gottesman. Next, there are summaries of research on monozygotic twinning after single embryo transfer, a twin study of mononucleosis susceptibility, cerebral injury following twin-to-twin transfusion syndrome surgery, and a correction and clarification regarding an article by Segal (2016) on the Brazilian Twin Registry. Human interest articles cover a hospital whose 2015 newborns included 16 pairs of twins born in 1 month, the death of an identical twin playwright, twin themes in advertising, conjoined twins separated in Saudi Arabia, and the dismissed charges of the murder of one twin by her co-twin. PMID:27524469

  20. Genetic determinants of bone mass in adults. A twin study.

    PubMed Central

    Pocock, N A; Eisman, J A; Hopper, J L; Yeates, M G; Sambrook, P N; Eberl, S

    1987-01-01

    The relative importance of genetic factors in determining bone mass in different parts of the skeleton is poorly understood. Lumbar spine and proximal femur bone mineral density and forearm bone mineral content were measured by photon absorptiometry in 38 monozygotic and 27 dizygotic twin pairs. Bone mineral density was significantly more highly correlated in monozygotic than in dizygotic twins for the spine and proximal femur and in the forearm of premenopausal twin pairs, which is consistent with significant genetic contributions to bone mass at all these sites. The lesser genetic contribution to proximal femur and distal forearm bone mass compared with the spine suggests that environmental factors are of greater importance in the aetiology of osteopenia of the hip and wrist. This is the first demonstration of a genetic contribution to bone mass of the spine and proximal femur in adults and confirms similar findings of the forearm. Furthermore, bivariate analysis suggested that a single gene or set of genes determines bone mass at all sites. PMID:3624485

  1. [Adult identical twins with moyamoya disease].

    PubMed

    Kashihara, M; Oki, H; Sasaki, K; Soga, T; Ueda, S; Matsumoto, K

    1984-11-01

    Adult identical twins with Moyamoya disease are reported. Laboratory examinations such as blood types, AB, Rh(+), HLA (human leucocytic antigen) analysis [AW26(9), A26(10), BW62(15), BW61(40), CW3], and finger prints, and hairs confirmed that two patients were identical twins. Both had normal serum immunoglobulin levels and no anti-DNA antibodies. Patient No. 1, a 39-year-old female, was admitted to our service with chief complaints of nausea, vomiting and left hemiparesis with sudden onset on Oct 31, 1981. The patient had an episode of tetraplegia that occurred suddenly at 4 years of her age and lasted about a week. Motor weakness had completely disappeared but moderate mental retardation remained. She had been employed just prior to this attack. CT and angiographic examinations revealed ventricular hemorrhage with Moyamoya disease, which had miliary aneurysm in the branch of the right posterior choroidal artery. The operation of encephalomyosynangiosis was performed on her left hemisphere. The postoperative course was uneventful. Patient No. 2, the twin sister of patient No. 1, was in good health and mental state until 19 years of her age, when she suddenly lost consciousness and developed hemiparesis. After this attack, her motor function had recovered well. However, mental ability gradually deteriorated and she was admitted to a psychiatric ward. CT examination and angiographic studies were performed on Oct 12, 1982, and she was diagnosed as having Moyamoya disease.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Functional neuroimaging study in identical twin pairs discordant for regular cigarette smoking.

    PubMed

    Lessov-Schlaggar, Christina N; Lepore, Rebecca L; Kristjansson, Sean D; Schlaggar, Bradley L; Barnes, Kelly Anne; Petersen, Steven E; Madden, Pamela A F; Heath, Andrew C; Barch, Deanna M

    2013-01-01

    Despite the tremendous public health and financial burden of cigarette smoking, relatively little is understood about brain mechanisms that subserve smoking behavior. This study investigated the effect of lifetime regular smoking on brain processing in a reward guessing task using functional magnetic resonance imaging and a co-twin control study design in monozygotic (MZ) twin pairs that maximally controls for genetic and family background factors. Young adult (24-34 years) MZ female twin pairs (n = 15 pairs), discordant for regular smoking defined using Centers for Disease Control criteria as having smoked ≥100 cigarettes in their lifetime, were recruited from an ongoing genetic epidemiological longitudinal study of substance use and psychopathology. We applied hypothesis-driven region of interest (ROI) and whole-brain analyses to investigate the effect of regular smoking on reward processing. Reduced response to reward and punishment in regular compared with never-regular smokers was seen in hypothesis-driven ROI analysis of bilateral ventral striatum. Whole-brain analysis identified bilateral reward-processing regions that showed activation differences in response to winning or losing money but no effect of regular smoking; and frontal/parietal regions, predominantly in the right hemisphere, that showed robust effect of regular smoking but no effect of winning or losing money. Altogether, using a study design that maximally controls for group differences, we found that regular smoking had modest effects on striatal reward processing regions but robust effects on cognitive control/attentional systems. PMID:22340136

  3. Familial risk and ADHD-specific neural activity revealed by case-control, discordant twin pair design.

    PubMed

    Godinez, Detre A; Willcutt, Erik G; Burgess, Gregory C; Depue, Brendan E; Andrews-Hanna, Jessica R; Banich, Marie T

    2015-09-30

    Individuals with ADHD, as well as their family members who do not meet clinical criteria, have shown deficits in executive function. However, it remains unclear whether underlying neural alterations are familial or ADHD-specific. To investigate this issue, neural activation underlying executive function was assessed using functional magnetic resonance imaging during performance of a Stroop task in three groups of individuals: 20 young adults who were diagnosed with ADHD in childhood, their 20 dizygotic co-twins without ADHD in childhood, and 20 unrelated controls selected from dizygotic twin pairs in which neither twin had ADHD in childhood (total n=60). Implicating the frontoparietal network as a location of effects specific to ADHD, activation in the superior frontal (Brodmann's Area - BA 6) and parietal regions (BA 40) was significantly reduced in twins with childhood ADHD compared to both their control co-twins and unrelated control twins. Consistent with familial influences, activity in the anterior cingulate and insula was significantly reduced in both the twins with ADHD and their co-twins compared to the unrelated controls. These results show that both ADHD-specific and familial influences related to an ADHD diagnosis impact neural systems underlying executive function. PMID:26256128

  4. Stressful life events and depression among adolescent twin pairs.

    PubMed

    Boardman, Jason D; Alexander, Kari B; Stallings, Michael C

    2011-01-01

    Using the twin pairs sample from the National Longitudinal Study ofAdolescent Health, we estimate bivariate Cholesky models for the influence of stressful life events (SLEs) on depressive symptoms. We show that depressive symptoms (h2Depression = .28) and dependent SLEs (events influenced by an individual's behavior) are both moderately heritable (h2SLE Dependent = .43). We find no evidence for the heritability of independent SLEs. Results from the bivariate Cholesky model suggest that roughly one-half of the correlation between depression and dependent SLEs is due to common genetic factors. Our findings suggest that attempts to characterize the causal effect of SLEs on mental health should limit their list of SLEs to those that are outside of the control of the individual.

  5. Differentially Methylated Genomic Regions in Birth-Weight Discordant Twin Pairs.

    PubMed

    Chen, Mubo; Baumbach, Jan; Vandin, Fabio; Röttger, Richard; Barbosa, Eudes; Dong, Mingchui; Frost, Morten; Christiansen, Lene; Tan, Qihua

    2016-03-01

    Poor nutrition during critical growth phases may alter the structural and physiologic development of vital organs thus "programming" the susceptibility to adult-onset diseases and disease-related health conditions. Epigenome-wide association studies have been performed in birth-weight discordant twin pairs to find evidence for such "programming" effects, but no significant results emerged. We further investigated this issue using a new computational approach: Instead of probing single genomic sites for significant alterations in epigenetic marks, we scan for differentially methylated genomic regions. Whole genome DNA methylation levels were measured in whole blood from 150 pairs of adult identical twins discordant for birth-weight. Intrapair differential DNA methylation was associated with qualitative (large or small) and quantitative (percentage) birth-weight discordance at each genomic site using regression models adjusting for age and sex. Based on the regression results, genomic regions with consistent alteration patterns of DNA methylation were located and tested for significant robustness using computational permutation tests. This yielded an interesting genomic region on chromosome 1, which is significantly differentially methylated for quantitative birth-weight discordance. The region covers two genes (TYW3 and CRYZ) both reportedly associated with metabolism. We conclude that prenatal conditions for birth-weight discordance may result in persistent epigenetic modifications potentially affecting even adult health. PMID:26831219

  6. Functional Neuroimaging Study in Identical Twin Pairs Discordant for Regular Cigarette Smoking

    PubMed Central

    Lessov-Schlaggar, Christina N.; Lepore, Rebecca L.; Kristjansson, Sean D.; Schlaggar, Bradley L.; Barnes, Kelly Anne; Petersen, Steven E.; Madden, Pamela A. F.; Heath, Andrew C.; Barch, Deanna M.

    2012-01-01

    Despite the tremendous public health and financial burden of cigarette smoking, relatively little is understood about brain mechanisms that subserve smoking behavior. This study investigated the effect of lifetime regular smoking on brain processing in a reward guessing task using functional magnetic resonance imaging (fMRI) and a cotwin-control study design in monozygotic (MZ) twin pairs that maximally controls for genetic and family background factors. Young adult (24–34 years) MZ female twin pairs (n=15 pairs), discordant for regular smoking defined using Centers for Disease Control (CDC) criteria as having smoked ≥100 cigarettes lifetime were recruited from an ongoing genetic epidemiological longitudinal study of substance use and psychopathology. We applied hypothesis-driven region of interest and whole brain analyses to investigate the effect of regular smoking on reward processing. Reduced response to reward and punishment in regular compared to never-regular smokers was seen in hypothesis-driven region of interest analysis of bilateral ventral striatum. Whole brain analysis identified bilateral reward-processing regions that showed activation differences in response to winning or losing money but no effect of regular smoking; and frontal/parietal regions, predominantly in the right hemisphere, that showed robust effect of regular smoking but no effect of winning or losing money. Altogether, using a study design that maximally controls for group differences, we found that regular smoking had modest effects on striatal reward processing regions but robust effects on cognitive control/attentional systems. PMID:22340136

  7. Large Autosomal Copy-Number Differences within Unselected Monozygotic Twin Pairs are Rare.

    PubMed

    McRae, Allan F; Visscher, Peter M; Montgomery, Grant W; Martin, Nicholas G

    2015-02-01

    Monozygotic (MZ) twins form an important system for the study of biological plasticity in humans. While MZ twins are generally considered to be genetically identical, a number of studies have emerged that have demonstrated copy-number differences within a twin pair, particularly in those discordant for disease. The rate of autosomal copy-number variation (CNV) discordance within MZ twin pairs was investigated using a population sample of 376 twin pairs genotyped on Illumina Human610-Quad arrays. After CNV calling using both QuantiSNP and PennCNV followed by manual annotation, only a single CNV difference was observed within the MZ twin pairs, being a 130 KB duplication of chromosome 5. Five other potential discordant CNV were called by the software, but excluded based on manual annotation of the regions. It is concluded that large CNV discordance is rare within MZ twin pairs, indicating that any CNV difference found within phenotypically discordant MZ twin pairs has a high probability of containing the causal gene(s) involved. PMID:25578400

  8. Twins and politics: political careers and political attitudes / twin research reviews: pair-bonding; facial expressivity in reared apart twins; educating multiples / stories that move and amaze us: a military funeral; a twins' reunion; Egyptian septuplets; rare occupations.

    PubMed

    Segal, Nancy L

    2008-12-01

    Twins and twin research are providing fresh insights into the roots of political behavior. This topic is approached from dual perspectives: why some individuals choose to become politicians, and why individuals vary in their political attitudes and interests. Reviews of timely twin studies in the areas of pair-bonding, facial expressivity and education follow. Finally, some extraordinary events in the lives of twins and their families are revealed.

  9. Genetic and Environmental Regulation on Longitudinal Change of Metabolic Phenotypes in Danish and Chinese Adult Twins

    PubMed Central

    Li, Shuxia; Kyvik, Kirsten Ohm; Pang, Zengchang; Zhang, Dongfeng; Duan, Haiping; Tan, Qihua; Hjelmborg, Jacob; Kruse, Torben; Dalgård, Christine

    2016-01-01

    Objective The rate of change in metabolic phenotypes can be highly indicative of metabolic disorders and disorder-related modifications. We analyzed data from longitudinal twin studies on multiple metabolic phenotypes in Danish and Chinese twins representing two populations of distinct ethnic, cultural, social-economic backgrounds and geographical environments. Materials and Methods The study covered a relatively large sample of 502 pairs of Danish adult twins followed up for a long period of 12 years with a mean age at intake of 38 years (range: 18–65) and a total of 181 Chinese adult twin pairs traced for about 7 years with a mean baseline age of 39.5 years (range: 23–64). The classical twin models were fitted to the longitudinal change in each phenotype (Δphenotype) to estimate the genetic and environmental contributions to the variation in Δphenotype. Results Moderate to high contributions by the unique environment were estimated for all phenotypes in both Danish (from 0.51 for low density lipoprotein cholesterol up to 0.72 for triglycerides) and Chinese (from 0.41 for triglycerides up to 0.73 for diastolic blood pressure) twins; low to moderate genetic components were estimated for long-term change in most of the phenotypes in Danish twins except for triglycerides and hip circumference. Compared with Danish twins, the Chinese twins tended to have higher genetic control over the longitudinal changes in lipids (except high density lipoprotein cholesterol) and glucose, higher unique environmental contribution to blood pressure but no genetic contribution to longitudinal change in body mass traits. Conclusion Our results emphasize the major contribution of unique environment to the observed intra-individual variation in all metabolic phenotypes in both samples, and meanwhile reveal differential patterns of genetic and common environmental regulation on changes over time in metabolic phenotypes across the two samples. PMID:26862898

  10. A pair of monozygotic twins discordant for homosexuality: sex-dimorphic behavior and penile volume responses.

    PubMed

    McConaghy, N; Blaszczynski, A

    1980-04-01

    In reports of identical twins discordant for homosexuality, the homosexual twins showed the effeminacy syndrome in childhood. This has been considered evidence that the homosexuality comes from the twin himself. The possibility that the heterosexual twin was denying homosexuality has never been excluded. A pair of identical male twins discordant for homosexuality are reported. They showed significant differences in their penile volume responses to moving pictures of male and female nudes indicative of sexual orientations consistent with their statements. The homosexual twin showed the effeminacy syndrome. Aspects of the syndrome can be induced in mammals by altering their hormonal environment during some critical period in their intrauterine development. Discordance for homosexuality in identical twins could be due to one's being exposed to a different hormonal level during such a critical period.

  11. Movement Disorders in a Twins Pair: A Casual Expression or Genetic Determination?

    ERIC Educational Resources Information Center

    Gennaro, Leonarda; Russo, Luigi; Losito, Luciana; Zaccaria, Alessia; De Rinaldis, Marta; Trabacca, Antonio

    2010-01-01

    A twin study is an excellent means of assessing the contribution of heritability to motor behaviour. We present a movement video-analysis of a monozygotic twins pair with a motor repertoire which is almost totally constituted by persistent and subcontinuous motor stereotypies. Purpose: The specific aim of this study is to verify the heritable…

  12. Child abuse of one of a pair of twins in Japan.

    PubMed

    Tanimura, M; Matsui, I; Kobayashi, N

    1990-11-24

    A nationwide survey in Japan on child abuse and neglect revealed that 10% of the victims were products of multiple births. None of the victims who were singletons had multiple-birth siblings, and only in a few cases were both twins abused. The findings indicated that one rather than both of a pair of twins was likely to be abused in Japan. Abuse of both twins was likely when there were serious parental or family problems, whereas abuse of one twin was associated with the child's medical problems or non-home care. There was no instance of abuse of a pair of twins when both were handicapped. Comparisons of the abused twin with the non-abused co-twin and examination of the abuser's attitude to the victim suggested that the difference between twins in their development or in their response to parents increased the stress of child-rearing and encouraged favouritism, which resulted in abuse of only one twin. Comparison by parents of children with their siblings may be a common factor in general child abuse because it is a natural thing for parents to do. PMID:1978124

  13. Associations Between Fast-Food Consumption and Body Mass Index: A Cross-Sectional Study in Adult Twins.

    PubMed

    Cohen-Cline, Hannah; Lau, Richard; Moudon, Anne V; Turkheimer, Eric; Duncan, Glen E

    2015-08-01

    Obesity is a substantial health problem in the United States, and is associated with many chronic diseases. Previous studies have linked poor dietary habits to obesity. This cross-sectional study aimed to identify the association between body mass index (BMI) and fast-food consumption among 669 same-sex adult twin pairs residing in the Puget Sound region around Seattle, Washington. We calculated twin-pair correlations for BMI and fast-food consumption. We next regressed BMI on fast-food consumption using generalized estimating equations (GEE), and finally estimated the within-pair difference in BMI associated with a difference in fast-food consumption, which controls for all potential genetic and environment characteristics shared between twins within a pair. Twin-pair correlations for fast-food consumption were similar for identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins, but were substantially higher in MZ than DZ twins for BMI. In the unadjusted GEE model, greater fast-food consumption was associated with larger BMI. For twin pairs overall, and for MZ twins, there was no association between within-pair differences in fast-food consumption and BMI in any model. In contrast, there was a significant association between within-pair differences in fast-food consumption and BMI among DZ twins, suggesting that genetic factors play a role in the observed association. Thus, although variance in fast-food consumption itself is largely driven by environmental factors, the overall association between this specific eating behavior and BMI is largely due to genetic factors.

  14. Associations Between Fast-Food Consumption and Body Mass Index: A Cross-Sectional Study in Adult Twins.

    PubMed

    Cohen-Cline, Hannah; Lau, Richard; Moudon, Anne V; Turkheimer, Eric; Duncan, Glen E

    2015-08-01

    Obesity is a substantial health problem in the United States, and is associated with many chronic diseases. Previous studies have linked poor dietary habits to obesity. This cross-sectional study aimed to identify the association between body mass index (BMI) and fast-food consumption among 669 same-sex adult twin pairs residing in the Puget Sound region around Seattle, Washington. We calculated twin-pair correlations for BMI and fast-food consumption. We next regressed BMI on fast-food consumption using generalized estimating equations (GEE), and finally estimated the within-pair difference in BMI associated with a difference in fast-food consumption, which controls for all potential genetic and environment characteristics shared between twins within a pair. Twin-pair correlations for fast-food consumption were similar for identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins, but were substantially higher in MZ than DZ twins for BMI. In the unadjusted GEE model, greater fast-food consumption was associated with larger BMI. For twin pairs overall, and for MZ twins, there was no association between within-pair differences in fast-food consumption and BMI in any model. In contrast, there was a significant association between within-pair differences in fast-food consumption and BMI among DZ twins, suggesting that genetic factors play a role in the observed association. Thus, although variance in fast-food consumption itself is largely driven by environmental factors, the overall association between this specific eating behavior and BMI is largely due to genetic factors. PMID:26005202

  15. Remembered parental bonding in adult twins: genetic and environmental influences.

    PubMed

    Lichtenstein, Paul; Ganiban, Jody; Neiderhiser, Jenae M; Pedersen, Nancy L; Hansson, Kjell; Cederblad, Marianne; Elthammar, Olof; Reiss, David

    2003-07-01

    One common assumption in psychology is the impact of parenting and parent-child relationships on the child's adjustment throughout the life span. Studies have indicated that there are genetic influences on memories of parenting, but how these influences are mediated has not typically been investigated. A sample of 150 pairs of monozygotic and 176 pairs of dizygotic Swedish twin women reported on personal characteristics and on remembered relationships with their mother and father using the Parental Bonding Instrument (PBI). Quantitative genetic analyses showed moderate genetic influences for remembered parental warmth, which also was partly explained by genetic influences for optimism, aggression, and humor. The other two PBI scales, authoritarianism and protectiveness, showed only shared and nonshared environmental influences. One interpretation of the findings is that heritable personal characteristics of children elicit parental warmth. However, other explanations such as personality characteristics influencing how experiences with parents are interpreted or circumstances in adult life that affect the recall of experiences could not be ruled out. PMID:14574139

  16. The road not taken: life experiences in monozygotic twin pairs discordant for major depression

    PubMed Central

    Kendler, KS; Halberstadt, LJ

    2012-01-01

    In an effort to understand how environmental experiences contribute to risk for major depression (MD), we conducted joint autobiographical interviews with 14 pairs of monozygotic twins (mean age 51.2) rigorously discordant for a lifetime history of MD. Twelve of the pairs could be sorted into four broad categories. In two pairs, discordance was associated with a single traumatic event occurring to the affected twin. In seven pairs, the well twin had one stable, long-term, successful romantic relationship, whereas the affected co-twin had romantic reversals one or more of which precipitated depressive episodes. These pairs varied in the degree to which the romantic problems seemed to arise from bad luck or poor choices. In one pair, occupational difficulties were strongly related to discordance in experiences with MD. In two pairs, several mechanisms seemed to be at work. Discordance in the quality of intimate love relationships was the most common etiological factor revealed by interview in these discordant pairs, with single dramatic events and occupational problems being considerably rarer. Even in this best of natural experiments, the causal interrelationship between personality, environment and depressive episodes was not always clear. Many pairs illustrated the protective effects of planfulness and the malignant effect of cumulative continuity where early difficulties in relationships shaped the subsequent life course. These results speak both to the importance of environmental influences on human well-being and psychopathology, and the complexity of the causal paths underlying their effects. PMID:22641178

  17. DNA Methylation Changes in the IGF1R Gene in Birth Weight Discordant Adult Monozygotic Twins.

    PubMed

    Tsai, Pei-Chien; Van Dongen, Jenny; Tan, Qihua; Willemsen, Gonneke; Christiansen, Lene; Boomsma, Dorret I; Spector, Tim D; Valdes, Ana M; Bell, Jordana T

    2015-12-01

    Low birth weight (LBW) can have an impact on health outcomes in later life, especially in relation to pre-disposition to metabolic disease. Several studies suggest that LBW resulting from restricted intrauterine growth leaves a footprint on DNA methylation in utero, and this influence likely persists into adulthood. To investigate this further, we performed epigenome-wide association analyses of blood DNA methylation using Infinium HumanMethylation450 BeadChip profiles in 71 adult monozygotic (MZ) twin pairs who were extremely discordant for birth weight. A signal mapping to the IGF1R gene (cg12562232, p = 2.62 × 10(-8)), was significantly associated with birth weight discordance at a genome-wide false-discovery rate (FDR) of 0.05. We pursued replication in three additional independent datasets of birth weight discordant MZ pairs and observed the same direction of association, but the results were not significant. However, a meta-analysis across the four independent samples, in total 216 birth-weight discordant MZ twin pairs, showed a significant positive association between birth weight and DNA methylation differences at IGF1R (random-effects meta-analysis p = .04), and the effect was particularly pronounced in older twins (random-effects meta-analysis p = .008, 98 older birth-weight discordant MZ twin pairs). The results suggest that severe intra-uterine growth differences (birth weight discordance >20%) are associated with methylation changes in the IGF1R gene in adulthood, independent of genetic effects.

  18. Phonological and Morphosyntactic Intervention for a Twin Pair

    ERIC Educational Resources Information Center

    Feehan, Angela; Francis, Charmaine; Bernhardt, B. May; Colozzo, Paola

    2015-01-01

    Two 6-year-old male fraternal twins each received 8 weeks of morphosyntactic and phonological intervention in counterbalanced order. Progress occurred for most targets and measures, with each child making greater progress for either phonology or morphosyntax during the corresponding unitary-domain block. Gains were maintained during the subsequent…

  19. Determination of Zygosity in Adult Chinese Twins Using the 450K Methylation Array versus Questionnaire Data.

    PubMed

    Wang, Biqi; Gao, Wenjing; Yu, Canqing; Cao, Weihua; Lv, Jun; Wang, Shengfeng; Pang, Zengchang; Cong, Liming; Wang, Hua; Wu, Xianping; Li, Liming

    2015-01-01

    Previous studies have shown that both single nucleotide polymorphisms (SNPs) and questionnaires-based method can be used for twin zygosity determination, but few validation studies have been conducted using Chinese populations. In the current study, we recruited 192 same sex Chinese adult twin pairs to evaluate the validity of using genetic markers-based method and questionnaire-based method in zygosity determination. We considered the relatedness analysis based on more than 0.6 million SNPs genotyping as the golden standards for zygosity determination. After quality control, qualified twins were left for relatedness analysis based on identical by descent calculation. Then those same sex twin pairs were included in the zygosity questionnaire validation analysis. Logistic regression model was applied to assess the discriminant ability of age, sex and the three questions in zygosity determination. Leave one out cross-validation was used as a measurement of internal validation. The results of zygosity determination based on 65 SNPs in 450k methylation array were all consistent with genotyping. Age, gender, questions of appearance confused by strangers and previously perceived zygosity consisted of the most predictable model with a consistency rate of 0.8698, cross validation predictive error of 0.1347. For twin studies with genotyping and\\or 450k methylation array, there would be no need to conduct other zygosity testing for the sake of costs consideration. PMID:25927701

  20. Integration of DNA sequence and DNA methylation changes in monozygotic twin pairs discordant for schizophrenia.

    PubMed

    Castellani, C A; Melka, M G; Gui, J L; O'Reilly, R L; Singh, S M

    2015-12-01

    Schizophrenia is a complex mental disorder with high heritability (80%), extensive genetic heterogeneity, environmental contributions and only 50% concordance in discordant monozygotic (MZ) twins. Discordant MZ twins provide an exceptional opportunity to assess patient specific genome-wide genetic and epigenetic changes that may account for the disease phenotype. A combined analysis of genetic and epigenetic changes on the same twin pairs is expected to provide a more effective approach for two reasons. First, it is now possible to generate relatively reliable complete genome sequences as well as promoter methylation states on an individual level and second, the unaffected twin that originated from the same zygote provides a near perfect genetic match for contrast and comparison. This report deals with the combined analysis of DNA sequence data and methylation data on two pairs of discordant MZ twins that have been clinically followed for over 20 years. Results on Family 1 show that 58 genes differ in DNA sequence as well as promoter methylation in a schizophrenia-affected twin as compared to her healthy co-twin. The corresponding number for family 2 was 13. The two lists are over represented by neuronal genes and include a number of known schizophrenia candidate genes and drug targets. The results argue that changes in multiple genes via co-localized genetic and epigenetic alteration contribute to a liability threshold that is necessary for development of schizophrenia. This novel hypothesis, although logical, remains to be validated.

  1. Diversity of Gut Microbiota Metabolic Pathways in 10 Pairs of Chinese Infant Twins

    PubMed Central

    Wang, Yan; Zhou, Jianli; Zhou, Wenhao

    2016-01-01

    Early colonization of gut microbiota in human gut is a complex process. It remains unclear when gut microbiota colonization occurs and how it proceeds. In order to study gut microbiota composition in human early life, the present study recruited 10 healthy pairs of twins, including five monozygotic (MZ) and five dizygotic (DZ) twin pairs, whose age ranged from 0 to 6 years old. 20 fecal samples from these twins were processed by shotgun metagenomic sequencing, and their averaged data outputs were generated as 2G per sample. We used MEGAN5 to perform taxonomic and functional annotation of the metagenomic data, and systematically analyzed those 20 samples, including Jaccard index similarity, principle component, clustering, and correlation analyses. Our findings indicated that within our study group: 1) MZ-twins share more microbes than DZ twins or non-twin pairs, 2) gut microbiota distribution is relatively stable at metabolic pathways level, 3) age represents the strongest factor that can account for variation in gut microbiota, and 4) a clear metabolic pathway shift can be observed, which speculatively occurs around the age of 1 year old. This research will serve as a base for future studies of gut microbiota-related disease research. PMID:27583441

  2. Diversity of Gut Microbiota Metabolic Pathways in 10 Pairs of Chinese Infant Twins.

    PubMed

    Zhou, Shaoming; Xu, Ruihuan; He, Fusheng; Zhou, Jiaxiu; Wang, Yan; Zhou, Jianli; Wang, Mingbang; Zhou, Wenhao

    2016-01-01

    Early colonization of gut microbiota in human gut is a complex process. It remains unclear when gut microbiota colonization occurs and how it proceeds. In order to study gut microbiota composition in human early life, the present study recruited 10 healthy pairs of twins, including five monozygotic (MZ) and five dizygotic (DZ) twin pairs, whose age ranged from 0 to 6 years old. 20 fecal samples from these twins were processed by shotgun metagenomic sequencing, and their averaged data outputs were generated as 2G per sample. We used MEGAN5 to perform taxonomic and functional annotation of the metagenomic data, and systematically analyzed those 20 samples, including Jaccard index similarity, principle component, clustering, and correlation analyses. Our findings indicated that within our study group: 1) MZ-twins share more microbes than DZ twins or non-twin pairs, 2) gut microbiota distribution is relatively stable at metabolic pathways level, 3) age represents the strongest factor that can account for variation in gut microbiota, and 4) a clear metabolic pathway shift can be observed, which speculatively occurs around the age of 1 year old. This research will serve as a base for future studies of gut microbiota-related disease research. PMID:27583441

  3. Pairing the Adult Learner and Boutique Wineries

    ERIC Educational Resources Information Center

    Holyoke, Laura; Heath-Simpson, Delta

    2013-01-01

    This study explored connections between adult learners and their experiences in the context of small boutique wineries operating in the start-up phase of the organizational life cycle. The research objective was to gain insight regarding the pairing of adult learners with the entering of a specialty industry. Fourteen individuals from four…

  4. De novo and inherited CNVs in MZ twin pairs selected for discordance and concordance on Attention Problems.

    PubMed

    Ehli, Erik A; Abdellaoui, Abdel; Hu, Yueshan; Hottenga, Jouke Jan; Kattenberg, Mathijs; van Beijsterveldt, Toos; Bartels, Meike; Althoff, Robert R; Xiao, Xiangjun; Scheet, Paul; de Geus, Eco J; Hudziak, James J; Boomsma, Dorret I; Davies, Gareth E

    2012-10-01

    Copy number variations (CNVs) have been reported to be causal suspects in a variety of psychopathologic traits. We investigate whether de novo and/or inherited CNVs contribute to the risk for Attention Problems (APs) in children. Based on longitudinal phenotyping, 50 concordant and discordant monozygotic (MZ) twin pairs were selected from a sample of ∼3200 MZ pairs. Two types of de novo CNVs were investigated: (1) CNVs shared by both MZ twins, but not inherited (pre-twinning de novo CNVs), which were detected by comparing copy number (CN) calls between parents and twins and (2) CNVs not shared by co-twins (post-twinning de novo CNVs), which were investigated by comparing the CN calls within MZ pairs. The association between the overall CNV burden and AP was also investigated for CNVs genome-wide, CNVs within genes and CNVs outside of genes. Two de novo CNVs were identified and validated using quantitative PCR: a pre-twinning de novo duplication in a concordant-unaffected twin pair and a post-twinning deletion in the higher scoring twin from a concordant-affected pair. For the overall CNV burden analyses, affected individuals had significantly larger CNVs that overlapped with genes than unaffected individuals (P=0.008). This study suggests that the presence of larger CNVs may increase the risk for AP, because they are more likely to affect genes, and confirms that MZ twins are not always genetically identical. PMID:22490988

  5. Asthma and height in twins: a cohort and within-pair analyses study.

    PubMed

    Protudjer, Jennifer L P; Lundholm, Cecilia; Almqvist, Catarina

    2015-04-01

    In singletons, asthma may be associated with shorter height and delayed growth during adolescence. Yet, these studies do not account for heritability of asthma, puberty/menarche, and height. We aimed to study the association between asthma and puberty in boys and menarche in girls, and height, in a cohort of twins and subsequently in same-sex twin pairs discordant for asthma. From a Swedish twin cohort, parent- and self-reported data on asthma, puberty/menarche, and height were collected. Pubertal staging was established via the Petersen index. Logistic and linear regression was used to estimate associations between asthma and puberty/menarche and height, respectively. For within-pair analyses in twins discordant for asthma, conditional logistic and linear regression were used. Data on 2,658 (49.1% boys) twins were included. Among boys, asthma prevalence was 8.2% at 8-9 years and 10.2% at 13-14 years. Corresponding numbers for girls were 4.2% and 4.9%, respectively. In the entire cohort, no statistically significant associations were found between current asthma and puberty/menarche. Boys with asthma were shorter than boys without asthma at 8-9 years (on average, 1.86 [0.17-3.56] cm, p = .03) and at 13-14 years (on average, 2.94 [0.98-4.91] cm, p = .003) but not at 19-20 years. No such associations were found for girls. Within same-sex twin pairs discordant for asthma, no statistically significant associations were found for either sex. Twin boys, but not girls, with asthma were shorter than those without asthma. Non-statistically significant estimates from within-pair analyses suggest the association is partly confounded by genetic or familial environmental factors. PMID:25761570

  6. Individual Differences in Dynamic Measures of Verbal Learning Abilities in Young Twin Pairs and Their Older Siblings

    ERIC Educational Resources Information Center

    van Soelen, Inge L. C.; van den Berg, Stephanie M.; Dekker, Peter H.; van Leeuwen, Marieke; Peper, Jiska S.; Hulshoff Pol, Hilleke E.; Boomsma, Dorret I.

    2009-01-01

    We explored the genetic background of individual differences in dynamic measures of verbal learning ability in children, using a Dutch version of the Auditory Verbal Learning Test (AVLT). Nine-year-old twin pairs (N = 112 pairs) were recruited from the Netherlands Twin Register. When possible, an older sibling between 10 and 14 years old…

  7. Mapping corpus callosum morphology in twin pairs discordant for bipolar disorder.

    PubMed

    Bearden, Carrie E; van Erp, Theo G M; Dutton, Rebecca A; Boyle, Christina; Madsen, Sarah; Luders, Eileen; Kieseppa, Tuula; Tuulio-Henriksson, Annamari; Huttunen, Matti; Partonen, Timo; Kaprio, Jaakko; Lönnqvist, Jouko; Thompson, Paul M; Cannon, Tyrone D

    2011-10-01

    Callosal volume reduction has been observed in patients with bipolar disorder, but whether these deficits reflect genetic vulnerability to the illness remains unresolved. Here, we used computational methods to map corpus callosum abnormalities in a population-based sample of twin pairs discordant for bipolar disorder. Twenty-one probands with bipolar I disorder (mean age 44.4 ± 7.5 years; 48% female), 19 of their non-bipolar co-twins, and 34 demographically matched control twin individuals underwent magnetic resonance imaging. Three-dimensional callosal surface models were created to visualize its morphologic variability and to localize group differences. Neurocognitive correlates of callosal area differences were additionally investigated in a subsample of study participants. Bipolar (BPI) probands, but not their co-twins, showed significant callosal thinning and area reduction, most pronounced in the genu and splenium, relative to healthy twins. Altered callosal curvature was additionally observed in BPI probands. In bipolar probands and co-twins, genu and splenium midsagittal areas were significantly correlated with verbal processing speed and response inhibition. These findings suggest that aberrant connections between cortical regions--possibly reflecting decreased myelination of white matter tracts--may be involved in bipolar pathophysiology. However, findings of callosal thinning appear to be disease related, rather than reflecting genetic vulnerability to bipolar illness. PMID:21383237

  8. Heritability of thyroid peroxidase autoantibody levels in type 1 diabetes: evidence from discordant twin pairs

    PubMed Central

    Wang, Bin; Hawa, Mohammed I.; Rijsdijk, Frühling V.; Fain, Pamela R.; Paschou, Stavroula A.; Boehm, Bernhard O.; Steck, Andrea K.; Snieder, Harold

    2016-01-01

    Aims/hypothesis The discordance status of (autoimmune) type 1 diabetes within monozygotic twin pairs points to the importance of environmental factors. The aim of this study was to investigate whether the environmental events causing type 1 diabetes influence thyroid autoimmunity. Methods Monozygotic and dizygotic twins discordant for type 1 diabetes from the UK and USA were tested for thyroid peroxidase autoantibodies (TPOA) by radioimmunoassay. Using quantitative genetic model fitting of a liability-threshold model we estimated the contribution of genetic (heritability) and environmental factors to TPOA. Results TPOA positivity was higher in females than in males in both cohorts and was associated with later age at diagnosis in the UK and combined cohorts (p<0.01). TPOA did not specifically segregate with type 1 diabetes in the twin pairs (p>0.2 in all groups). The best-fitting models showed heritability (95% CI) estimates for TPOA of 63% (37%, 80%) for the UK and 80% (51%, 92%) for US twins, while the best-fitting meta-analysis model of the two twin cohorts combined included additive genetic and unique environmental factors with a heritability estimate of 69% (50%, 82%). Conclusions/interpretation Risk of thyroid autoimmunity, defined by TPOA, in the context of autoimmune diabetes is, substantially, genetically determined in discordant twin pairs. Environmental factors leading to type 1 diabetes were not the same as those involved with thyroid autoimmunity. It follows that it is as important to investigate for thyroid autoimmunity in relatives of type 1 diabetes patients as it is in the patients themselves. PMID:26070305

  9. Path analytic, sib-pair linkage and co-twin control studies of asthma and atopy

    SciTech Connect

    Duffy, D.L.; Healey, S.C.; Martin, N.G.

    1994-09-01

    Asthma and atopy are complex traits with multifactorial determinants, and require appropriate choice of phenotypes and analyses, including a linkage analysis of the putative 11q atopy locus. Participants in a large registry-based twin study of asthma were invited to take part in clinical testing. A total of 863 individuals including 419 complete twin pairs (where one or both members reported a history of wheeze) underwent histamine inhalation challenge, allergen skin prick testing, and venesection. Total serum immunoglobulin E (IgE) and bronchial responsiveness (BR) to histamine were highest in those who had wheezed most recently, and whose skin tests demonstrated allergy to house dust mite, cockroach, and rye grass. In ascertainment-corrected path analyses (FISHER), the heritability of IgE and BR were both 60%. Monozygotic (MZ) co-twin control analyses suggested house dust mite sensitization was the single strongest environmentally controlled risk factor for wheeze, while path analyses suggested genetic determination. In dizygotic (DZ) co-twin control analyses, sensitization to grasses was also an important predictor, suggesting pollinosis to be genetically correlated with wheezing, rather than causative. Multivariate path analyses suggested separate (correlated) genetic factors for BR, IgE, and allergy to house dust mite. A sib-pair (Haseman-Elston) linkage analysis of 220 DZ twin pairs did not support linkage to the high-affinity IgE receptor beta-subunit gene on 11q13 of atopy or BR. More recent linkage analyses that include parental genotyping will also be discussed. We conclude that the atopic phenotype consists of a number of traits with specific genetic allergens. Exposure to particular allergens can then cause specific outcomes, such as asthma.

  10. Risk Factors and Relationship of Cutaneous and Uveal Melanocytic Lesions in Monozygotic and Dizygotic Twin Pairs

    PubMed Central

    Varga, Anita; Szabó, Hajnalka; Orvos, Hajnalka; Kemény, Lajos; Oláh, Judit

    2016-01-01

    Background The similar genetic background of a pair of twins, and the similar environmental impacts to which they are exposed allow an exact and objective investigation of various constitutional and environmental factors in naevus development. As far as we are aware, this is the first published survey that simultaneously examines cutaneous and ocular pigmented lesions in an appreciable sample of identical and non-identical twins. Methods 172 pairs of twins of Caucasian origin were included in this study. A whole-body skin examination and a detailed ophthalmological examination were performed to determine the density of melanocytic lesions. A standardized questionnaire was used to assess the data relating to constitutional, sun exposure and other variables. Results A notably high proportion of the subjects (36.78%) manifested one or more clinically atypical melanocytic naevi (CAMNs), and approximately one-third (31.4%) of them at least one benign uveal pigmented lesion (BUPL). The incidence of iris freckles (IFs), iris naevi (INs) and choroidal naevi (CHNs) proved to be 25.35%, 5.98% and 3.52%, respectively. The interclass correlation coefficients for common melanocytic naevi (CMNs), CAMNs, and INs were 0.77, 0.76 and 0.86 in monozygotic twins, as compared with 0.5, 0.27 and 0.25 in dizygotic twin pairs, respectively. A statistically significant correlation was found between the prevalence of CAMNs and that of INs. Conclusions This significant correlation suggests the existence of a subgroup of Caucasian people with an increased susceptibility to both cutaneous and ocular naevus formation. There is accumulating evidence that, besides the presence of cutaneous atypical naevi, INs can serve as a marker of a predisposed phenotype at risk of uveal melanoma. The correlation between cutaneous and ocular pigmented lesions underlines the need for the adequate ophthalmological screening of subjects with CAMNs and INs. PMID:27486750

  11. Genetic and Environmental Etiologies of Reading Difficulties: DeFries-Fulker Analysis of Reading Performance Data from Twin Pairs and Their Non-Twin Siblings

    ERIC Educational Resources Information Center

    Astrom, Raven L.; Wadsworth, Sally J.; Olson, Richard K.; Willcutt, Erik G.; DeFries, John C.

    2012-01-01

    Reading performance data from 254 pairs of identical (MZ) and 420 pairs of fraternal (DZ) twins, 8.0 to 20.0 years of age, were subjected to multiple regression analyses. An extension of the DeFries-Fulker (DF) analysis (DeFries & Fulker, 1985, 1988) that facilitated inclusion of data from 303 of their nontwin siblings was employed. In addition to…

  12. Intended Sensitive and Harsh Caregiving Responses to Infant Crying: The Role of Cry Pitch and Perceived Urgency in an Adult Twin Sample

    ERIC Educational Resources Information Center

    Out, Dorothee; Pieper, Suzanne; Bakermans-Kranenburg, Marian J.; Zeskind, Philip Sanford; van IJzendoorn, Marinus H.

    2010-01-01

    Objective: To examine the underlying mechanisms of adults' intended caregiving responses to cry sounds in a behavioral genetic design and to investigate the role of cry pitch and perceived urgency in sensitive and harsh caregiving responses. Methods: The sample consisted of 184 adult twin pairs (18-69 years), including males and females, parents…

  13. Non-random X chromosome inactivation in an affected twin in a monozygotic twin pair discordant for Wiedemann-Beckwith syndrome

    SciTech Connect

    Oestavik, R.E.; Eiklid, K.; Oerstavik, K.H.

    1995-03-27

    Wiedemann-Beckwith syndrome (WBS) is a syndrome including exomphalos, macroglossia, and generalized overgrowth. The locus has been assigned to 11p15, and genomic imprinting may play a part in the expression of one or more genes involved. Most cases are sporadic. An excess of female monozygotic twins discordant for WBS have been reported, and it has been proposed that this excess could be related to the process of X chromosome inactivation. We have therefore studied X chromosome inactivation in 13-year-old monozygotic twin girls who were discordant for WBS. In addition, both twins had Tourette syndrome. The twins were monochorionic and therefore the result of a late twinning process. This has also been the case in previously reported discordant twin pairs with information on placentation. X chromosome inactivation was determined in DNA from peripheral blood cells by PCR analysis at the androgen receptor locus. The affected twin had a completely skewed X inactivation, where the paternal allele was on the active X chromosome in all cells. The unaffected twin had a moderately skewed X inactivation in the same direction, whereas the mother had a random pattern. Further studies are necessary to establish a possible association between the expression of WBS and X chromosome inactivation. 18 refs., 2 figs., 1 tab.

  14. Health-Related Findings Among Twin Pairs Discordant for Leisure-Time Physical Activity for 32 Years: The TWINACTIVE Study Synopsis.

    PubMed

    Leskinen, Tuija; Kujala, Urho M

    2015-06-01

    We are lacking very long-term and controlled intervention studies investigating the effects of habitual physical activity on health-related factors. To address this gap, we performed a natural experiment by identifying same-sex twin pairs in which the co-twins of each pair differed with respect to leisure-time physical-activity habits throughout their adult life. Our criterion for the discordance was that the same co-twin had a higher leisure time-activity volume than that of the other member of the pair at the majority -- if not all -- of the follow-up time points according to reported/interviewed physical-activity data. Overall, we identified and conducted multidimensional health-related measurements (including fitness, body composition, cardiometabolic risk factor levels, bone and arterial status, and exercise motivation) of 16 twin pairs (seven monozygotic (MZ) and nine dizygotic (DZ) pairs, mean age 60 years) who had persistent discordance in leisure-time physical-activity habits over three decades (TWINACTIVE study). In our discordant-pair study design, after adjusting for sequence-level genes, both systemic-level metabolic, and site-specific structural findings differed significantly in the pairwise analysis in MZ pairs only. These findings included intrapair differences in accumulated fat depots and structure of heart, arteries, and bones. In addition, our study revealed intrapair differences in metabolic and regulatory pathways, which may partly explain the mechanistic links between long-term physical activity, phenotypic changes, and decreased risk of cardiometabolic diseases. PMID:25906784

  15. Twin-based study of the complex interplay between childhood maltreatment, socioeconomic status and adult memory.

    PubMed

    Goldberg, Ximena; Alemany, Silvia; Fatjó-Vilas, Mar; González-Ortega, Itxaso; González-Pinto, Ana; Cuesta, Manuel J; Fañanás, Lourdes

    2013-08-01

    Childhood maltreatment and low socioeconomic status (SES) are considered stressful environmental events with lasting detrimental effects on adult mental health and associated cognitive performance, such as memory. However, the association between childhood maltreatment and low SES remains unclear, probably due to design limitations and putative confounding factors. Particular concerns have been raised on genetic influences, as genetic background may modulate the effects of environmental stressors. The aim of the present study was to examine the effect of childhood maltreatment on adult memory in low- and high-SES subjects, free of confounding due to other environmental and genetic influences. A monozygotic twin design based on 188 healthy adult subjects (94 twin pairs) from the general population was conducted. This design based on genetically identical individuals allowed disentangling the unique environmental effects of childhood maltreatment on memory, which was explored in low and high SES. Results showed that the unique environmental effects of childhood maltreatment were only evident in the high-SES group (β = -0.22; SE = 0.08; p < 0.01; 95 % CI = -0.375 to -0.066). By contrast, no evidence for this effect could be detected in the more stressful low-SES group. These results suggest that enriched environments may provide a more stable context where early stressful experiences can influence cognitive processes. This study provides preliminary support for the inclusion of environmental enrichment in studies addressing the impact of childhood maltreatment on adult cognition and psychiatric disorders.

  16. Twin-based study of the complex interplay between childhood maltreatment, socioeconomic status and adult memory.

    PubMed

    Goldberg, Ximena; Alemany, Silvia; Fatjó-Vilas, Mar; González-Ortega, Itxaso; González-Pinto, Ana; Cuesta, Manuel J; Fañanás, Lourdes

    2013-08-01

    Childhood maltreatment and low socioeconomic status (SES) are considered stressful environmental events with lasting detrimental effects on adult mental health and associated cognitive performance, such as memory. However, the association between childhood maltreatment and low SES remains unclear, probably due to design limitations and putative confounding factors. Particular concerns have been raised on genetic influences, as genetic background may modulate the effects of environmental stressors. The aim of the present study was to examine the effect of childhood maltreatment on adult memory in low- and high-SES subjects, free of confounding due to other environmental and genetic influences. A monozygotic twin design based on 188 healthy adult subjects (94 twin pairs) from the general population was conducted. This design based on genetically identical individuals allowed disentangling the unique environmental effects of childhood maltreatment on memory, which was explored in low and high SES. Results showed that the unique environmental effects of childhood maltreatment were only evident in the high-SES group (β = -0.22; SE = 0.08; p < 0.01; 95 % CI = -0.375 to -0.066). By contrast, no evidence for this effect could be detected in the more stressful low-SES group. These results suggest that enriched environments may provide a more stable context where early stressful experiences can influence cognitive processes. This study provides preliminary support for the inclusion of environmental enrichment in studies addressing the impact of childhood maltreatment on adult cognition and psychiatric disorders. PMID:23188190

  17. [A 20-year follow-up study of a sample of 50 pairs of twins with neurotic-psychosomatic disorders].

    PubMed

    Muhs, A; Schepank, H; Manz, R

    1990-01-01

    As part of a research project, examination was made of a sample of 50 pairs of twins (21 pairs of identical twins, 16 pairs of non-identical twins of the same sex, and 13 pairs of male-female twins [n = 100 test persons]) between 1963 and 1969 and again recently after a period of 20 years. The index twins were drawn from among the patients who made use of the services of an out-patient psychotherapeutic clinic, and they were determined to be either psychoneurotic, character neurotic, or psychosomatically ill. The question examined was again one of nature vs. nurture. Identical twins showed a significantly higher similarity with regard to the seriousness of their neuroses and the manifestation of neurotic symptoms than did non-identical twins. Noticeable similarities existed in cases of depressive disturbances, disturbances of oral and aggressive behavior, and disturbances of interpersonal contact. With regard to the influence of variables in the environment, we examined the effect of factors in early childhood on neurotic development. Lack of a reference person, a negative attitude on the part of parents toward the child, etc., frustration within and outside the family have an effect on the manifestation of neuroses and on the course of their development. The influence of early childhood factors on the degree of neurotic disorder is still to be noted in the current point prevalence.

  18. [A 20-year follow-up study of a sample of 50 pairs of twins with neurotic-psychosomatic disorders].

    PubMed

    Muhs, A; Schepank, H; Manz, R

    1990-01-01

    As part of a research project, examination was made of a sample of 50 pairs of twins (21 pairs of identical twins, 16 pairs of non-identical twins of the same sex, and 13 pairs of male-female twins [n = 100 test persons]) between 1963 and 1969 and again recently after a period of 20 years. The index twins were drawn from among the patients who made use of the services of an out-patient psychotherapeutic clinic, and they were determined to be either psychoneurotic, character neurotic, or psychosomatically ill. The question examined was again one of nature vs. nurture. Identical twins showed a significantly higher similarity with regard to the seriousness of their neuroses and the manifestation of neurotic symptoms than did non-identical twins. Noticeable similarities existed in cases of depressive disturbances, disturbances of oral and aggressive behavior, and disturbances of interpersonal contact. With regard to the influence of variables in the environment, we examined the effect of factors in early childhood on neurotic development. Lack of a reference person, a negative attitude on the part of parents toward the child, etc., frustration within and outside the family have an effect on the manifestation of neuroses and on the course of their development. The influence of early childhood factors on the degree of neurotic disorder is still to be noted in the current point prevalence. PMID:2305597

  19. Genetic and environmental contributions to food use patterns of young adult twins

    PubMed Central

    Keskitalo, Kaisu; Silventoinen, Karri; Tuorila, Hely; Perola, Markus; Pietiläinen, Kirsi H; Rissanen, Aila; Kaprio, Jaakko

    2009-01-01

    The contribution of genetic factors to individual differences in food use was estimated in a large population-based twin cohort of young adults (22- to 27-year-old). Male and female twins (n=2009 complete twin pairs) evaluated use-frequencies of 24 food items using 5 categories (1=never - 5=several times a day) in a postal questionnaire. Foods were categorized by factor analysis. Estimates of the relative proportions of additive genetic, shared environmental, and unshared environmental effects on the use-frequency of food items and factor scores were obtained by quantitative genetic modeling of twin data based on linear structural equations. Four factors of food use were identified: “healthy” foods, high-fat foods, sweet foods, and meats. The variance of the use-frequency of food items and food categories was explained by additive genetic and unshared environmental influences, whereas shared environmental factors did not contribute to food use. The average proportions of genetic effects on the total variance of the use-frequency of food items and food categories were 40% and 45%, respectively. Sex differences were observed in the magnitude of genetic influences for use-frequency of four food items (chocolate, other sweets, fried foods, and meat), and in genetic factors underlying the use of three (fresh vegetables, fruits, and cheeses) items. In conclusion, family environment does not appear to influence the food use of young adults and thus nutritional education should be targeted at this age group to support development of healthy eating patterns. In addition, the results illuminate the importance of the sex-specific genetic effects on food use. PMID:17897688

  20. Brain Activation during Memory Encoding in Type 2 Diabetes Mellitus: A Discordant Twin Pair Study.

    PubMed

    Wood, Amanda G; Chen, Jian; Moran, Christopher; Phan, Thanh; Beare, Richard; Cooper, Kimberley; Litras, Stacey; Srikanth, Velandai

    2016-01-01

    Type 2 diabetes mellitus increases the risk of dementia and neuronal dysfunction may occur years before perceptible cognitive decline. We aimed to study the impact of type 2 diabetes on brain activation during memory encoding in middle-aged people, controlling for age, sex, genes, and early-shared environment. Twenty-two twin pairs discordant for type 2 diabetes mellitus (mean age 60.9 years) without neurological disease were recruited from the Australian Twin Registry (ATR) and underwent functional magnetic resonance imaging (fMRI) during a memory encoding task, cognitive tests, and structural MRI. Type 2 diabetes was associated with significantly reduced activation in left hemisphere temporoparietal regions including angular gyrus, supramarginal gyrus, and middle temporal gyrus and significantly increased activation in bilateral posteriorly distributed regions. These findings were present in the absence of within-pair differences in standard cognitive test scores, brain volumes, or vascular lesion load. Differences in activation were more pronounced among monozygotic (MZ) pairs, with MZ individuals with diabetes also displaying greater frontal activation. These results provide evidence for preclinical memory-related neuronal dysfunction in type 2 diabetes. They support the search for modifiable later-life environmental factors or epigenetic mechanisms linking type 2 diabetes and cognitive decline. PMID:27314047

  1. Brain Activation during Memory Encoding in Type 2 Diabetes Mellitus: A Discordant Twin Pair Study

    PubMed Central

    Wood, Amanda G.; Chen, Jian; Moran, Christopher; Phan, Thanh; Beare, Richard; Cooper, Kimberley; Litras, Stacey; Srikanth, Velandai

    2016-01-01

    Type 2 diabetes mellitus increases the risk of dementia and neuronal dysfunction may occur years before perceptible cognitive decline. We aimed to study the impact of type 2 diabetes on brain activation during memory encoding in middle-aged people, controlling for age, sex, genes, and early-shared environment. Twenty-two twin pairs discordant for type 2 diabetes mellitus (mean age 60.9 years) without neurological disease were recruited from the Australian Twin Registry (ATR) and underwent functional magnetic resonance imaging (fMRI) during a memory encoding task, cognitive tests, and structural MRI. Type 2 diabetes was associated with significantly reduced activation in left hemisphere temporoparietal regions including angular gyrus, supramarginal gyrus, and middle temporal gyrus and significantly increased activation in bilateral posteriorly distributed regions. These findings were present in the absence of within-pair differences in standard cognitive test scores, brain volumes, or vascular lesion load. Differences in activation were more pronounced among monozygotic (MZ) pairs, with MZ individuals with diabetes also displaying greater frontal activation. These results provide evidence for preclinical memory-related neuronal dysfunction in type 2 diabetes. They support the search for modifiable later-life environmental factors or epigenetic mechanisms linking type 2 diabetes and cognitive decline. PMID:27314047

  2. Increased Frequency of Micronuclei in Adults with a History of Childhood Sexual Abuse: A Discordant Monozygotic Twin Study

    PubMed Central

    York, Timothy P.; Brumelle, Jenni; Juusola, Jane; Kendler, Kenneth S.; Eaves, Lindon J.; Amstadter, Ananda B.; Aggen, Steven H.; Jones, Kimberly H.; Ferreira-Gonzalez, Andrea; Jackson-Cook, Colleen

    2013-01-01

    Background Childhood sexual abuse (CSA) is a traumatic life event associated with an increased lifetime risk for psychopathology/morbidity. The long-term biological consequences of CSA-elicited stress on chromosomal stability in adults are unknown. The primary aim of this study was to determine if the rate of acquired chromosomal changes, measured using the cytokinesis-block micronucleus assay on stimulated peripheral blood lymphocytes, differs in adult female monozygotic twins discordant for CSA. Methods Monozygotic twin pairs discordant for CSA were identified from a larger population-based sample of female adult twins for whom the experience of CSA was assessed by self-report (51 individuals including a reference sample). Micronuclei (MN) contain chromatin from structurally normal or abnormal chromosomes that are excluded from the daughter nuclei during cell division and serve as a biomarker to assess acquired chromosomal instability. Results Female twins exposed to CSA exhibited a 1.63-fold average increase in their frequency of MN compared to their nonexposed genetically identical cotwins (Paired t-test, t16 = 2.65, P = 0.017). No additional effects of familial factors were detected after controlling for the effect of CSA exposure. A significant interaction between CSA history and age was observed, suggesting that the biological effects of CSA on MN formation may be cumulative. Conclusions These data support a direct link between CSA exposure and MN formation measured in adults that is not attributable to genetic or environmental factors shared by siblings. Further research is warranted to understand the biological basis for the observed increase in acquired chromosomal findings in people exposed to CSA and to determine if acquired somatic chromosomal abnormalities/somatic clonal mosaicism might mediate the adult pathology associated with CSA. PMID:23383158

  3. Maternal Hypomethylation of KvDMR in a Monozygotic Male Twin Pair Discordant for Beckwith-Wiedemann Syndrome.

    PubMed

    Elalaoui, S C; Garin, I; Sefiani, A; Perez de Nanclares, G

    2014-01-01

    Beckwith-Wiedemann syndrome (BWS; OMIM 130650) is a heterogeneous overgrowth syndrome characterized by visceromegaly, macroglossia, tumor predisposition, and other congenital abnormalities. BWS is usually associated with abnormalities of chromosome 11p15, including (epi)genetic changes, paternal disomy and point mutations. A number of identical twin pairs, mostly female, have been reported to be clinically discordant for BWS. Studies of monozygotic twins discordant for BWS provide more information about failure in the DNA methylation maintenance machinery during very early embryonic development. Here, we report a case of monozygotic male twins discordant for BWS phenotype. Methylation analysis of the 2 imprinted domains at 11p15.5 (H19DMR and KvDMR) was performed by methylation-specific MLPA and pyrosequencing of DNA extracted from peripheral blood and buccal swabs of both twins. Hypomethylation at KvDMR was identified in both cell types of the affected twin, whereas his healthy brother presented hypomethylation only in blood cells and a normal methylation profile in buccal swab. For diagnostic purposes, it is important to remember that twins can share fetal circulation and possibly share hematopoietic stem cells early in development; therefore, the affected and unaffected twins can share an epigenotype that will resemble partial hypomethylation. If a patient is a twin, it is valuable to obtain a sample from a tissue other than blood. PMID:24550765

  4. Genetic factors in evolution of sleep length--a longitudinal twin study in Finnish adults.

    PubMed

    Hublin, Christer; Partinen, Markku; Koskenvuo, Markku; Kaprio, Jaakko

    2013-10-01

    Genetic factors affect many aspects of sleep, such as sleep length. We investigated the contribution of genetic factors to stability and change of sleep length among adults over a 15-year period. In this representative follow-up study we used the Finnish Twin Cohort as the study population. Questionnaire surveys were performed in 1975 (response rate 89%, 11,041 twin pairs; age ≥18 years), 1981 (84%, 9323; ≥24 years) and 1990 (77%, 4507; 33-60 years). Sleep was categorized as short (<7 h), average or long (>8 h). Pairwise similarity in monozygotic and dizygotic pairs was examined at each survey by age group and sex. Quantitative genetic modelling was used to estimate cross-sectional and longitudinal genetic effects. The proportion of variance in sleep length at one point in time that was accounted for by genetic effects was very stable over the study period, being 0.31 in 1975, 0.32 in 1981 and 0.30 in 1990. Longitudinal genetic modelling indicated that the correlations of genetic effects between the three measurement points were high: 0.85 between 1975 and 1981; 0.93 between 1981 and 1990; and 0.76 between 1975 and 1990. Despite a high contribution of environmental effects, their correlations over time were modest: 0.31 between 1975 and 1981; 0.33 between 1981 and 1990; and 0.18 between 1975 and 1990. In conclusion, genetic factors have a modest but stable effect on the evolution of sleep length over a long time span in adults. Multiple measures are a more robust basis for genetic analyses than a single cross-sectional measure. PMID:23509990

  5. The impact of sleep duration on adolescent development: a genetically informed analysis of identical twin pairs.

    PubMed

    Barnes, J C; Meldrum, Ryan C

    2015-02-01

    Recent work provides evidence that reduced sleep duration has detrimental effects on a range of developmentally related outcomes during adolescence. Yet, the potential confounding influence of genetic and shared environmental effects has not been sufficiently addressed. This study addresses this issue by analyzing cross-sectional data from the twin sub-sample of the first wave of the National Longitudinal Study of Adolescent Health [N ≈ 287 MZ (monozygotic) twin pairs; 50% male; 22% Black; mean age = 15.75]. Associations between sleep duration (measured through two different strategies, one tapping number of hours slept at night and the other measuring weeknight bedtimes) and seven outcomes (self-control, depressive symptoms, suicidal ideation, body mass index, violent delinquency, non-violent delinquency, and drug use) were estimated. Consistent with prior research, associations between sleep duration and several outcomes were statistically significant when using standard social science analytic methods. Yet, when employing a methodology that accounts for genetic and shared environmental influences, some of these associations were reduced to non-significance. Still, two consistent associations remained in that participants who reported sleeping fewer hours at night (or who reported later bedtimes) exhibited lower levels of self-control and more depressive symptoms. Implications of the findings and directions for future research are discussed.

  6. The impact of sleep duration on adolescent development: a genetically informed analysis of identical twin pairs.

    PubMed

    Barnes, J C; Meldrum, Ryan C

    2015-02-01

    Recent work provides evidence that reduced sleep duration has detrimental effects on a range of developmentally related outcomes during adolescence. Yet, the potential confounding influence of genetic and shared environmental effects has not been sufficiently addressed. This study addresses this issue by analyzing cross-sectional data from the twin sub-sample of the first wave of the National Longitudinal Study of Adolescent Health [N ≈ 287 MZ (monozygotic) twin pairs; 50% male; 22% Black; mean age = 15.75]. Associations between sleep duration (measured through two different strategies, one tapping number of hours slept at night and the other measuring weeknight bedtimes) and seven outcomes (self-control, depressive symptoms, suicidal ideation, body mass index, violent delinquency, non-violent delinquency, and drug use) were estimated. Consistent with prior research, associations between sleep duration and several outcomes were statistically significant when using standard social science analytic methods. Yet, when employing a methodology that accounts for genetic and shared environmental influences, some of these associations were reduced to non-significance. Still, two consistent associations remained in that participants who reported sleeping fewer hours at night (or who reported later bedtimes) exhibited lower levels of self-control and more depressive symptoms. Implications of the findings and directions for future research are discussed. PMID:24915970

  7. Discordant tooth agenesis and peg-shaped in a pair of monozygotic twins: Clinical and molecular study

    PubMed Central

    Antunes, Lívia Azeredo Alves; Küchler, Erika Calvano; Costa, Marcelo de Castro; Antunes, Leonardo Santos; Granjeiro, José Mauro

    2013-01-01

    The present report aimed to study an uncommon case of a pair of twins that presented a discordant dental phenotype. Family investigation, clinical, radiographic examination and molecular analysis were performed in both girls. Molecular analysis confirmed the monozygosity by deoxyribonucleic acid chip technology. One twin presented tooth agenesis in left upper lateral incisor and peg-shaped on the contra lateral side while the other twin had no dental alterations. The dental casts study employed digital caliper to compare morphological dimensions and showed alteration only in peg-shaped tooth. In conclusion, this study provide support that one or more mutated gene could cause discordances in dental phenotype in these monozygotic twins. PMID:24379875

  8. Coordination difficulty and internalizing symptoms in adults: A twin/sibling study.

    PubMed

    Waszczuk, Monika A; Leonard, Hayley C; Hill, Elisabeth L; Rowe, Richard; Gregory, Alice M

    2016-05-30

    Increased anxiety and depression symptoms have been reported in individuals with neurodevelopmental disorders, and have been found to be associated with motor coordination difficulties, but little is known about the etiology of these associations. This study aimed to assess genetic, shared (making twins/siblings alike) and non-shared (individual-specific) environmental influences on the association between poor coordination and symptoms of anxiety and depressed mood using a sample of adult twin and sibling pairs. Participants were asked about their coordination skill and anxiety and depression symptoms. About half of the variance in coordination difficulty was explained by familial (combined genetic and shared environmental) influences, with the remaining variance explained by non-shared environmental influences. Phenotypic associations between coordination and anxiety (r=.46) and depression symptoms (r=.44) were largely underpinned by shared familial liability for the three traits. Non-shared environment accounted for about a third of the phenotypic association. Results suggest that both familial and non-shared environmental influences play a role in the etiology of coordination difficulty and its association with internalizing symptoms. The current study highlights that both biological and environmental pathways shared between these symptoms should be examined in future research to inform prevention and treatment approaches in clinical settings.

  9. A Twin Study of the Genetics of High Cognitive Ability Selected from 11,000 Twin Pairs in Six Studies from Four Countries

    PubMed Central

    Haworth, Claire M.A.; Wright, Margaret J.; Martin, Nicolas W.; Martin, Nicholas G.; Boomsma, Dorret I; Bartels, Meike; Posthuma, Danielle; Davis, Oliver S.P.; Brant, Angela M.; Corley, Robin P.; Hewitt, John K.; Iacono, William G.; McGue, Matthew; Thompson, Lee A.; Hart, Sara A.; Petrill, Stephen A.; Lubinski, David; Plomin, Robert

    2009-01-01

    Although much genetic research has addressed normal variation in intelligence, little is known about the etiology of high cognitive abilities. Using data from 11,000 twin pairs (age range = 6 – 71 years) from the Genetics of High Cognitive Abilities (GHCA) Consortium, we investigated the genetic and environmental etiologies of high general cognitive ability (g). Age-appropriate psychometric cognitive tests were administered to the twins and used to create g scores standardized within each study. Liability-threshold model fitting was used to estimate genetic and environmental parameters for the top 15% of the distribution of g. Genetic influence for high g was substantial (0.50, with a 95% confidence interval of 0.41 – 0.60). Shared environmental influences were moderate (0.28, 0.19 – 0.37). We conclude that genetic variation contributes substantially to high g in Australia, the Netherlands, the United Kingdom and the United States. PMID:19381794

  10. Motives for and barriers to physical activity in twin pairs discordant for leisure time physical activity for 30 years.

    PubMed

    Aaltonen, S; Leskinen, T; Morris, T; Alen, M; Kaprio, J; Liukkonen, J; Kujala, U

    2012-02-01

    Long-term persistent physical activity is important in the prevention of chronic diseases, but a large number of people do not participate in physical activity to obtain health benefits. The purpose of this study was to examine the motives and perceived barriers to long-term engagement in leisure time physical activity. Same-sex twin pairs (N=16, mean age 60) discordant for physical activity over 30 years were identified from the Finnish Twin Cohort. We evaluated participants' physical activity motivation with the 73-item Recreational Exercise Motivation Measure and assessed barriers to physical activity with a 25-item questionnaire. The characteristics of physical activity motivation and perceived barriers between the active and inactive co-twins were analysed using paired tests. Motives related to the sub-dimensions of enjoyment and physical fitness and psychological state were the most important reasons for participation in physical activity among all the twin individuals analysed. The sub-dimensions mastery (p=0.018, Cohen's d=0.76), physical fitness (p=0.029, Cohen's d=0.69), and psychological state (p=0.039, Cohen's d=0.65) differed significantly between active and inactive co-twins. More than half of the participants reported no reasons for not being physically active. If reasons existed, participation in physical activity was deterred mostly by pain and various health problems. This study found no differences in perceived barriers between active and inactive co-twins. We conclude from our results that the main factors promoting persistent leisure time physical activity were participants' wish to improve or maintain their physical skills or techniques, a feeling that exercise would improve their mental and physical health and that they found the activity enjoyable. This study helps us understand the importance of the role of motives and the minor role of perceived barriers for engagement in persistent physical activity. PMID:22318531

  11. Aging as accelerated accumulation of somatic variants: whole-genome sequencing of centenarian and middle-aged monozygotic twin pairs.

    PubMed

    Ye, Kai; Beekman, Marian; Lameijer, Eric-Wubbo; Zhang, Yanju; Moed, Matthijs H; van den Akker, Erik B; Deelen, Joris; Houwing-Duistermaat, Jeanine J; Kremer, Dennis; Anvar, Seyed Yahya; Laros, Jeroen F J; Jones, David; Raine, Keiran; Blackburne, Ben; Potluri, Shobha; Long, Quan; Guryev, Victor; van der Breggen, Ruud; Westendorp, Rudi G J; 't Hoen, Peter A C; den Dunnen, Johan; van Ommen, Gert Jan B; Willemsen, Gonneke; Pitts, Steven J; Cox, David R; Ning, Zemin; Boomsma, Dorret I; Slagboom, P Eline

    2013-12-01

    It has been postulated that aging is the consequence of an accelerated accumulation of somatic DNA mutations and that subsequent errors in the primary structure of proteins ultimately reach levels sufficient to affect organismal functions. The technical limitations of detecting somatic changes and the lack of insight about the minimum level of erroneous proteins to cause an error catastrophe hampered any firm conclusions on these theories. In this study, we sequenced the whole genome of DNA in whole blood of two pairs of monozygotic (MZ) twins, 40 and 100 years old, by two independent next-generation sequencing (NGS) platforms (Illumina and Complete Genomics). Potentially discordant single-base substitutions supported by both platforms were validated extensively by Sanger, Roche 454, and Ion Torrent sequencing. We demonstrate that the genomes of the two twin pairs are germ-line identical between co-twins, and that the genomes of the 100-year-old MZ twins are discerned by eight confirmed somatic single-base substitutions, five of which are within introns. Putative somatic variation between the 40-year-old twins was not confirmed in the validation phase. We conclude from this systematic effort that by using two independent NGS platforms, somatic single nucleotide substitutions can be detected, and that a century of life did not result in a large number of detectable somatic mutations in blood. The low number of somatic variants observed by using two NGS platforms might provide a framework for detecting disease-related somatic variants in phenotypically discordant MZ twins. PMID:24182360

  12. A Comparison of Disease Burden Between Twins and Control Pairs in Medicare: Quantification of Heredity's Role in Human Health.

    PubMed

    Sorace, James; Rogers, Michael; Millman, Michael; Rogers, Daniel; Price, Kyle; Queen, Susan; Worrall, Chris; Kelman, Jeffrey

    2015-10-01

    To quantify heredity's effects on the burden of illness in the Medicare population, this study linked information between participants in a research twin registry to a comprehensive set of Medicare claims. To calculate disease categories, the authors used the Centers for Medicare & Medicaid Services Hierarchical Conditions Categories (HCC) model that was developed to risk adjust Medicare's capitation payments to private health care plans based on the health expenditure risk of their enrollees. Using the Medicare database, 2 sets of unrelated but demographically matched control pairs (MCPs) were generated, one specific for the monozygotic twin population and the second specific for the dizygotic twin population. The concordance and correlation rates of the 70 HCC categories for the 2 twin populations, in comparison to their corresponding MCP, was then calculated using Medicare claims data from 1991 through 2011. When indicated, HCCs for which there was a statistically significant difference between the twin and corresponding MCP control group were analyzed by calculating concordance and correlation rates of the International Classification of Diseases, Ninth Revision codes that compose the HCC. Findings reveal that monozygotic twins share 6.5% more HCC disease categories than their MCP while dizygotic twins share 3.8% more HCC disease categories than their MCP. Atrial fibrillation is a highly heritable disease category, a finding consistent with prior literature describing the heritability of the cardiac arrhythmias. These findings are consistent with qualitative assessments of heredity's role found in previous models of population health, and provide both novel methods and quantitative evidence to support future model development. PMID:25658666

  13. A Comparison of Disease Burden Between Twins and Control Pairs in Medicare: Quantification of Heredity's Role in Human Health.

    PubMed

    Sorace, James; Rogers, Michael; Millman, Michael; Rogers, Daniel; Price, Kyle; Queen, Susan; Worrall, Chris; Kelman, Jeffrey

    2015-10-01

    To quantify heredity's effects on the burden of illness in the Medicare population, this study linked information between participants in a research twin registry to a comprehensive set of Medicare claims. To calculate disease categories, the authors used the Centers for Medicare & Medicaid Services Hierarchical Conditions Categories (HCC) model that was developed to risk adjust Medicare's capitation payments to private health care plans based on the health expenditure risk of their enrollees. Using the Medicare database, 2 sets of unrelated but demographically matched control pairs (MCPs) were generated, one specific for the monozygotic twin population and the second specific for the dizygotic twin population. The concordance and correlation rates of the 70 HCC categories for the 2 twin populations, in comparison to their corresponding MCP, was then calculated using Medicare claims data from 1991 through 2011. When indicated, HCCs for which there was a statistically significant difference between the twin and corresponding MCP control group were analyzed by calculating concordance and correlation rates of the International Classification of Diseases, Ninth Revision codes that compose the HCC. Findings reveal that monozygotic twins share 6.5% more HCC disease categories than their MCP while dizygotic twins share 3.8% more HCC disease categories than their MCP. Atrial fibrillation is a highly heritable disease category, a finding consistent with prior literature describing the heritability of the cardiac arrhythmias. These findings are consistent with qualitative assessments of heredity's role found in previous models of population health, and provide both novel methods and quantitative evidence to support future model development.

  14. Ischiopagus and diprosopus in India: two pairs of conjoined twins perceived as incarnations of Hindu deities.

    PubMed

    Tubbs, R Shane; Ditty, Benjamin; Bosmia, Anand N; Bosmia, Arpan N

    2015-02-01

    This article briefly reviews two specific types of conjoined twins, ischiopagus and diprosopus, and discusses recent cases of such twins born in India. Some members of the Hindu community worshiped these conjoined twins as incarnations of Hindu deities. In discussing this phenomenon, the authors aim to elucidate certain features of the faith tradition of Hinduism itself. The reception of these conjoined twins as incarnations of Hindu deities can be understood by examining two salient features of Hindu polytheism: the pictorial depiction of Hindu deities with multiple appendages and the concept of an incarnation, or avatar, of a Hindu deity. PMID:23733407

  15. Population based study of prevalence of islet cell autoantibodies in monozygotic and dizygotic Danish twin pairs with insulin dependent diabetes mellitus.

    PubMed Central

    Petersen, J. S.; Kyvik, K. O.; Bingley, P. J.; Gale, E. A.; Green, A.; Dyrberg, T.; Beck-Nielsen, H.

    1997-01-01

    OBJECTIVE: To study the comparative importance of environment and genes in the development of islet cell autoimmunity associated with insulin dependent diabetes mellitus. DESIGN: Population based study of diabetic twins. SETTING: Danish population. SUBJECTS: 18 monozygotic and 36 dizygotic twin pairs with one or both partners having insulin dependent diabetes. MAIN OUTCOME MEASURES: Presence of islet cell antibodies, insulin autoantibodies, and autoantibodies to glutamic acid decarboxylase (GAD65) in serum samples from twin pairs 10 years (range 0-30 years) and 9.5 years (2-30 years) after onset of disease. RESULTS: In those with diabetes the prevalence of islet cell antibodies, insulin autoantibodies, and autoantibodies to glutamic acid decarboxylase in the 26 monozygotic twins was 38%, 85%, and 92%, respectively, and in the dizygotic twins was 57%, 70%, and 57%, respectively. In those without diabetes the proportions were 20%, 50%, and 40% in the 10 monozygotic twins and 26%, 49%, and 40% in the 35 dizygotic twins. CONCLUSION: There is no difference between the prevalence of islet cell autoantibodies in dizygotic and monozygotic twins without diabetes, suggesting that islet cell autoimmunity is environmentally rather than genetically determined. Furthermore, the prevalence of islet cell antibodies was higher in the non-diabetic twins than in other first degree relatives of patients with insulin dependent diabetes. This implies that the prenatal or early postnatal period during which twins are exposed to the same environment, in contrast with that experienced by first degree relatives, is of aetiological importance. PMID:9169400

  16. Genetic and environmental influences on spontaneous micronuclei frequencies in children and adults: a twin study.

    PubMed

    Jones, Kimberly H; York, Timothy P; Juusola, Jane; Ferreira-Gonzalez, Andrea; Maes, Hermine H; Jackson-Cook, Colleen

    2011-11-01

    The primary aim of this study was to quantify genetic and environmental influences on the frequency of spontaneously occurring micronuclei in children and adults. To meet this aim, a total of 63 male and female twin pairs and 19 singletons (145 individuals) were evaluated, ranging in age from 7 to 85 years. Micronuclei frequencies significantly increased with age for both genders (r = 0.49, P < 0.001), with the lowest and highest rates being seen in the 7- to 9 (mean = 0.56%, SD = .28) and 60- to 69-year-olds (mean = 2.12%, SD = 1.0), respectively. This age effect was significantly more pronounced in females than males (P = 0.017). In addition to the main effect of age, the completion of puberty in either gender (P = 0.036) and menopause in females (P = 0.024) was associated with a significant increase in micronuclei frequencies. Genetic model fitting indicated that influences from both additive genetic (65.2% of variance) and unique environmental (34.8% of variance) sources best explained the observed micronuclei frequencies in monozygotic and dizygotic twin pairs. Self-reported health conditions associated with an increased frequency of micronuclei included a history of allergies (P < 0.007) and migraines (P = 0.026). Multivitamin use was also associated with increased micronuclei frequencies (P = 0.004). In contrast, significantly lower micronuclei frequencies were associated with arthritis (P = 0.002), as well as consuming fruit (P = 0.014), green, leafy vegetables (P < 0.001) and/or folate-enriched bread (P = 0.035). A sex-specific effect, resulting in a significantly increased frequency of micronuclei with tobacco usage, was observed for females (but not males). Gender differences also moderated the impact of vitamin D and calcium consumption. In conclusion, the frequency of spontaneously arising micronuclei in humans is a complex trait, being influenced by both heritable genetic and environmental components. Recognition of factors contributing to baseline

  17. Sex Differences in the Pathways to Symptoms of Alcohol Use Disorder: A Study of Opposite-Sex Twin Pairs

    PubMed Central

    Kendler, Kenneth S.; Edwards, Alexis C.; Gardner, Charles O.

    2015-01-01

    Background We sought to develop an empirical, broad-based developmental model for sex differences in risk for symptoms of alcohol use disorders, here called alcohol problems (AP). Methods We assessed 18 risk factors in five developmental tiers in both members of 1,377 opposite sex dizygotic twin pairs from the Virginia population-based twin registry. Analyses were conducted by structural modeling, examining within-pair differences. Results The best-fitting model explained 73% of the variance in men and 71% in women for last year AP. 49% of paths differed significantly across sexes. Ten variables had appreciably different predictive effects on AP in males versus females. Three were stronger in females: familial risk, early onset anxiety disorders, and nicotine dependence. Seven predictors had a stronger total effect in males: novelty seeking, conduct disorder, childhood sexual abuse, parental loss, neuroticism, low self-esteem, and low marital satisfaction. Conclusions In a co-twin control design, which matches sisters and brothers on genetic and familial-environmental background, we found numerous sex differences in predictors of last year AP. Factors that were more prominent in men and in women were diverse, reflecting both internalizing and externalizing psychopathology. The model was slightly more successful at predicting AP in men than in women. PMID:25845269

  18. Does educational status impact adult mortality in Denmark? A twin approach.

    PubMed

    Madsen, Mia; Andersen, Anne-Marie Nybo; Christensen, Kaare; Andersen, Per Kragh; Osler, Merete

    2010-07-15

    To disentangle an independent effect of educational status on mortality risk from direct and indirect selection mechanisms, the authors used a discordant twin pair design, which allowed them to isolate the effect of education by means of adjustment for genetic and environmental confounding per design. The study is based on data from the Danish Twin Registry and Statistics Denmark. Using Cox regression, they estimated hazard ratios for mortality according to the highest attained education among 5,260 monozygotic and 11,088 dizygotic same-sex twin pairs born during 1921-1950 and followed during 1980-2008. Both standard cohort and intrapair analyses were conducted separately for zygosity, gender, and birth cohort. Educational differences in mortality were demonstrated in the standard cohort analyses but attenuated in the intrapair analyses in all subgroups but men born during 1921-1935, and no effect modification by zygosity was observed. Hence, the results are most compatible with an effect of early family environment in explaining the educational inequality in mortality. However, large educational differences were still reflected in mortality risk differences within twin pairs, thus supporting some degree of independent effect of education. In addition, the effect of education may be more pronounced in older cohorts of Danish men.

  19. APOL1 polymorphisms and development of CKD in an identical twin donor and recipient pair.

    PubMed

    Kofman, Tomek; Audard, Vincent; Narjoz, Céline; Gribouval, Olivier; Matignon, Marie; Leibler, Claire; Desvaux, Dominique; Lang, Philippe; Grimbert, Philippe

    2014-05-01

    We report an occurrence of progressive loss of transplant function and ultimately transplant failure after living related kidney transplantation involving monozygotic twin brothers of Afro-Caribbean origin who were both heterozygous for the G1 and G2 kidney disease risk alleles in the APOL1 gene, which encodes apolipoprotein L-I. A 21-year-old man with end-stage kidney disease of unknown cause received a kidney from his brother, who was confirmed as a monozygotic twin by microsatellite analysis. Thirty months after transplantation, the patient presented with proteinuria and decreased estimated glomerular filtration rate; a biopsy of the transplant showed typical focal segmental glomerulosclerosis lesions. He received steroid therapy, but progressed to kidney failure 5 years later. The twin brother had normal kidney function without proteinuria at the time of transplantation; however, 7 years later, he was found to have decreased estimated glomerular filtration rate (40mL/min/1.73m(2)) and proteinuria (protein excretion of 2.5g/d). APOL1 genotyping revealed that both donor and recipient were heterozygous for the G1 and G2 alleles. This case is in stark contrast to the expected course of kidney transplantation in identical twins and suggests a role for APOL1 polymorphisms in both the donor and recipient. PMID:24518129

  20. Uneven X inactivation in a female monozygotic twin pair with Fabry disease and discordant expression of a novel mutation in the alpha-galactosidase A gene.

    PubMed Central

    Redonnet-Vernhet, I; Ploos van Amstel, J K; Jansen, R P; Wevers, R A; Salvayre, R; Levade, T

    1996-01-01

    We describe two female monozygotic (MZ) twins heterozygous for Fabry disease, an X linked disorder resulting from the deficient activity of alpha-galactosidase A. While one of the twins was clinically affected, the other was asymptomatic. Enzymatic assay of alpha-galactosidase in blood leucocytes, skin fibroblasts, Epstein-Barr virus transformed lymphoid cell lines, and hair follicles of the twins and their parents confirmed the heterozygous status of the twins and indicated that Fabry disease had occurred as a result of a de novo mutation. The son of the unaffected twin sister was shown to be hemizygous. Molecular analysis of the alpha-galactosidase A gene permitted the identification of an as yet undescribed point mutation at position 10182 of exon 5 which causes an Asp to Asn substitution at codon 231. Single strand conformation polymorphism (SSCP) analysis again showed the heterozygous status of the twins and a normal pattern in their parents. The basis for the discordant expression of this d novo mutation in the twins was investigated by studying their X inactivation status. Analysis of the inactive X specific methylation at the androgen receptor gene showed unbalanced inactivation in the twins' fibroblasts and in opposite directions. While the maternally derived X chromosome was preferentially active in the asymptomatic twin, the paternal X chromosome was active in the other, affected twin and was found in her hemizygotic nephew. These data suggest that the paternal X chromosome carries the de novo alpha-galactosidase A mutation and that uneven X inactivation is the underlying mechanism for disease expression in this novel female MZ twin pair. This is the first documented case of female twins discordant for Fabry disease. Images PMID:8863162

  1. Assessment of heritability for personality, based on a short-form of the Eysenck Personality Inventory: a study of 12,898 twin pairs.

    PubMed

    Floderus-Myrhed, B; Pedersen, N; Rasmuson, I

    1980-03-01

    The influence of genetic factors for two personality dimensions was analyzed using data from 12,898 unselected twin pairs of the Swedish Twin Registry. The heritability index was 0.50 (men) and 0.58 (women) for psychosocial instability. Corresponding figures for psychosocial extraversion were 0.54 and 0.66. Thus, about half the phenotypic variation may be attributed to genetic factors.

  2. The Host Genotype and Environment Affect Strain Types of Bifidobacterium longum subsp. longum Inhabiting the Intestinal Tracts of Twins

    PubMed Central

    Zhang, Min; Hang, Xiaomin; Tan, Jing

    2015-01-01

    To investigate the influences of host genotype and environment on Bifidobacterium longum subsp. longum inhabiting human intestines at the strain level, six pairs of twins, divided into two groups (children and adults), were recruited. Each group consisted of two monozygotic (MZ) twin pairs and one dizygotic (DZ) twin pair. Child twins had been living together from birth, while adult twins had been living separately for 5 to 10 years. A total of 345 B. longum subsp. longum isolates obtained from 60 fecal samples from these twins were analyzed by multilocus sequence typing (MLST), and 35 sequence types (STs) were finally acquired. Comparison of strains within and between the twin pairs showed that no strains with identical STs were observed between unrelated individuals or within adult DZ twin pairs. Eight STs were found to be monophyletic, existing within MZ twins and child DZ twins. The similarity of strain types within child cotwins was significantly higher than that within adult cotwins, which indicated that environment was one of the important determinants in B. longum subsp. longum strain types inhabiting human intestines. However, although these differences between MZ and DZ twins were observed, it is still difficult to reach an exact conclusion about the impact of host genotype. This is mainly because of the limited number of subjects tested in the present study and the lack of strain types tracing in the same twin pairs from birth until adulthood. PMID:25956768

  3. DeFries-Fulker and Pearson-Aitken model-fitting analyses of reading performance data from selected and unselected twin pairs.

    PubMed

    Hawke, Jesse L; Stallings, Michael C; Wadsworth, Sally J; DeFries, John C

    2008-03-01

    Although a comparison of concordance rates for deviant scores in identical and fraternal twin pairs can provide prima facie evidence for a genetic etiology, information is not fully utilized when continuous measures are analyzed in a dichotomous manner. Thus, DeFries and Fulker (Behav Genet 15:467-473, 1985; Acta Genet Med Gemellol, 37:205-216, 1988) developed a regression-based methodology (DF analysis) to assess genetic etiology in both selected and unselected twin samples. While the DF analysis is a very versatile and relatively powerful statistical approach, it is not easily extended to the multivariate case. In contrast, structural equation models may be readily extended to analyze multivariate data sets (Neale and Cardon, Methodology for genetic studies of twins and families, 1992). However, such methodologies may yield biased estimates of additive genetic, shared environmental, and non-shared environmental influences when multivariate models are fitted to selected twin data. Therefore, the Pearson-Aitken (PA) selection formula (Aitken, Proc Edinburgh Math Soc B, 4:106-110, 1934) was used to analyze reading performance data from twins with reading difficulties (selected sample) and a population of normally-achieving twin pairs (control sample). As a comparison, DF models were also fitted to these same data sets. In general, resulting estimates of additive genetic, shared environmental, and non-shared environmental influences were similar when the DF and PA models were fitted to the data. However, the PA selection formula may be more readily generalized to the multivariate case.

  4. Parkinsonism in a pair of monozygotic CADASIL twins sharing the R1006C mutation: a transcranial sonography study.

    PubMed

    Ragno, Michele; Sanguigni, Sandro; Manca, Antonio; Pianese, Luigi; Paci, Cristina; Berbellini, Alfonso; Cozzolino, Valeria; Gobbato, Roberto; Peluso, Silvio; De Michele, Giuseppe

    2016-06-01

    Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the most common hereditary cerebral small vessel disease, is caused by mutations in the NOTCH3 gene on chromosome 19. Clinical manifestations of CADASIL include recurrent transient ischemic attacks, strokes, cognitive defects, epilepsy, migraine and psychiatric symptoms. Parkinsonian features have variably been reported in CADASIL patients, but only a few patients showed a clear parkinsonian syndrome. We studied two patients, a pair of monozygotic twins, carrying the R1006C mutation of the NOTCH3 gene and affected by a parkinsonian syndrome. For the first time in CADASIL patients, we used transcranial sonography (TCS) to assess basal ganglia abnormalities. TCS showed a bilateral hyperechogenic pattern of substantia nigra in one twin, and a right hyperechogenic pattern in the other. In both patients, lenticular nuclei showed a bilateral hyperechogenic pattern, and the width of the third ventricle was slightly increased. The TCS pattern found in our CADASIL patients is characteristic neither for Parkinson's disease, nor for vascular parkinsonism and seems to be specific and related to the disease-specific pathological features. PMID:26850715

  5. Behavioural observations of adult-child pairs at pedestrian crossings.

    PubMed

    Zeedyk, M Suzanne; Kelly, Laura

    2003-09-01

    Pedestrian accidents are a serious health risk to children in the UK and other Western countries. There remains a considerable amount to be learned about children's behaviour in real-traffic environments. The present study was intended to help fill this gap, by observing unobtrusively the behaviours of 123 adult-child pairs as they crossed the road at pedestrian light-controlled crossings. Eight behaviours were coded, including whether or not the pair stopped at the kerb, waited for the light to change, and checked to ensure traffic flow had stopped. Results showed that the adults observed provided reasonably good models of pedestrian behaviour, but that they rarely treated the crossing event as an opportunity to teach children explicitly about road safety. The only gender difference to emerge revealed that adults were more likely to hold girls' hands than boys' hands. No differences were observed in relation to (estimated) age of child. The implications of these findings for parental training programmes are explored.

  6. Birth Weight and Adult IQ, but Not Anxious-Depressive Psychopathology, Are Associated with Cortical Surface Area: A Study in Twins

    PubMed Central

    Córdova-Palomera, Aldo; Fatjó-Vilas, Mar; Falcón, Carles; Bargalló, Nuria; Alemany, Silvia; Crespo-Facorro, Benedicto; Nenadic, Igor; Fañanás, Lourdes

    2015-01-01

    Background Previous research suggests that low birth weight (BW) induces reduced brain cortical surface area (SA) which would persist until at least early adulthood. Moreover, low BW has been linked to psychiatric disorders such as depression and psychological distress, and to altered neurocognitive profiles. Aims We present novel findings obtained by analysing high-resolution structural MRI scans of 48 twins; specifically, we aimed: i) to test the BW-SA association in a middle-aged adult sample; and ii) to assess whether either depression/anxiety disorders or intellectual quotient (IQ) influence the BW-SA link, using a monozygotic (MZ) twin design to separate environmental and genetic effects. Results Both lower BW and decreased IQ were associated with smaller total and regional cortical SA in adulthood. Within a twin pair, lower BW was related to smaller total cortical and regional SA. In contrast, MZ twin differences in SA were not related to differences in either IQ or depression/anxiety disorders. Conclusion The present study supports findings indicating that i) BW has a long-lasting effect on cortical SA, where some familial and environmental influences alter both foetal growth and brain morphology; ii) uniquely environmental factors affecting BW also alter SA; iii) higher IQ correlates with larger SA; and iv) these effects are not modified by internalizing psychopathology. PMID:26086820

  7. Crossed cerebral lateralization for verbal and visuo-spatial function in a pair of handedness discordant monozygotic twins: MRI and fMRI brain imaging

    PubMed Central

    Lux, Silke; Keller, Simon; Mackay, Clare; Ebers, George; Marshall, John C; Cherkas, Lynne; Rezaie, Roozbeh; Roberts, Neil; Fink, Gereon R; Gurd, Jennifer M

    2008-01-01

    To examine the nature of hemispheric lateralization for neural processes underlying verbal fluency and visuo-spatial attention, we investigated a single pair of handedness discordant monozygotic (MzHd) twins. Imaging of the brain was undertaken using magnetic resonance imaging (MRI) and functional magnetic resonance imaging (fMRI) in combination with manual performance tasks. The twins were discordant for MRI anatomical asymmetries of the pars triangularis and planum temporale, whose asymmetry was consistent with verbal laterality on fMRI. Thus, the right-handed twin had left lateralized verbal with right lateralized visuo-spatial attention, while the left-handed twin had right lateralized verbal with left lateralized visuo-spatial activation; these data lend further support for to the conclusions of Sommer et al. PMID:18304205

  8. Common immune-related exposures/conditions and risk of non-Hodgkin lymphoma: a case-control study of disease-discordant twin pairs.

    PubMed

    Wang, Jun; Mack, Thomas M; Hamilton, Ann S; Hwang, Amie E; Nathwani, Bharat N; Masood, Kamil; Buchanan, Laura H; Bernstein, Leslie; Deapen, Dennis M; Martínez-Maza, Otoniel; Cozen, Wendy

    2015-09-01

    We evaluated the association between common immune system-altering experiences and non-Hodgkin lymphoma (NHL) risk using a case-control study of 162 like-sex twin pairs discordant for NHL, identified from the International Twin Study. Information on medical history and evidence of childhood exposure to microbes was obtained by questionnaire from 1998 to 2002. Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals. Intra-twin-pair agreement between twins on individual exposures was high (76%-97%). A negative association between NHL and seasonal hay fever (odds ratio (OR) = 0.28, 95% confidence interval (CI): 0.10, 0.75) and certain allergies (OR = 0.29, 95% CI: 0.13, 0.68) was observed. The number of atopic diseases was negatively associated with NHL (P for trend = 0.0003). A history of infectious mononucleosis was negatively associated with NHL risk (OR = 0.35, 95% CI: 0.14, 0.90). NHL risk was associated with more frequent childhood exposure to microbes during early life (P for trend = 0.04). No differences in association by NHL subtype were observed, although statistical power for these comparisons was low. These observations support the hypothesis that immune-related exposures, especially atopy, are associated with decreased NHL risk. Use of the within-twin-pair study design mitigates confounding by genome, family structure, and unmeasured characteristics of early childhood factors. PMID:26271116

  9. Common immune-related exposures/conditions and risk of non-Hodgkin lymphoma: a case-control study of disease-discordant twin pairs.

    PubMed

    Wang, Jun; Mack, Thomas M; Hamilton, Ann S; Hwang, Amie E; Nathwani, Bharat N; Masood, Kamil; Buchanan, Laura H; Bernstein, Leslie; Deapen, Dennis M; Martínez-Maza, Otoniel; Cozen, Wendy

    2015-09-01

    We evaluated the association between common immune system-altering experiences and non-Hodgkin lymphoma (NHL) risk using a case-control study of 162 like-sex twin pairs discordant for NHL, identified from the International Twin Study. Information on medical history and evidence of childhood exposure to microbes was obtained by questionnaire from 1998 to 2002. Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals. Intra-twin-pair agreement between twins on individual exposures was high (76%-97%). A negative association between NHL and seasonal hay fever (odds ratio (OR) = 0.28, 95% confidence interval (CI): 0.10, 0.75) and certain allergies (OR = 0.29, 95% CI: 0.13, 0.68) was observed. The number of atopic diseases was negatively associated with NHL (P for trend = 0.0003). A history of infectious mononucleosis was negatively associated with NHL risk (OR = 0.35, 95% CI: 0.14, 0.90). NHL risk was associated with more frequent childhood exposure to microbes during early life (P for trend = 0.04). No differences in association by NHL subtype were observed, although statistical power for these comparisons was low. These observations support the hypothesis that immune-related exposures, especially atopy, are associated with decreased NHL risk. Use of the within-twin-pair study design mitigates confounding by genome, family structure, and unmeasured characteristics of early childhood factors.

  10. Common Immune-Related Exposures/Conditions and Risk of Non-Hodgkin Lymphoma: A Case-Control Study of Disease-Discordant Twin Pairs

    PubMed Central

    Wang, Jun; Mack, Thomas M.; Hamilton, Ann S.; Hwang, Amie E.; Nathwani, Bharat N.; Masood, Kamil; Buchanan, Laura H.; Bernstein, Leslie; Deapen, Dennis M.; Martínez-Maza, Otoniel; Cozen, Wendy

    2015-01-01

    We evaluated the association between common immune system–altering experiences and non-Hodgkin lymphoma (NHL) risk using a case-control study of 162 like-sex twin pairs discordant for NHL, identified from the International Twin Study. Information on medical history and evidence of childhood exposure to microbes was obtained by questionnaire from 1998 to 2002. Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals. Intra-twin-pair agreement between twins on individual exposures was high (76%–97%). A negative association between NHL and seasonal hay fever (odds ratio (OR) = 0.28, 95% confidence interval (CI): 0.10, 0.75) and certain allergies (OR = 0.29, 95% CI: 0.13, 0.68) was observed. The number of atopic diseases was negatively associated with NHL (P for trend = 0.0003). A history of infectious mononucleosis was negatively associated with NHL risk (OR = 0.35, 95% CI: 0.14, 0.90). NHL risk was associated with more frequent childhood exposure to microbes during early life (P for trend = 0.04). No differences in association by NHL subtype were observed, although statistical power for these comparisons was low. These observations support the hypothesis that immune-related exposures, especially atopy, are associated with decreased NHL risk. Use of the within-twin-pair study design mitigates confounding by genome, family structure, and unmeasured characteristics of early childhood factors. PMID:26271116

  11. Kinetics of 3H-serotonin uptake by platelets in infantile autism and developmental language disorder (including five pairs of twins)

    SciTech Connect

    Katsui, T.; Okuda, M.; Usuda, S.; Koizumi, T.

    1986-03-01

    The kinetics of 5-HT uptake by platelets was studied in cases of infantile autism and developmental language disorder (DLD) and normal subjects. Two patients of the autism group were twins, and the seven patients of the DLD group were members of four pairs of twins. The Vmax values (means +/- SD) for autism and DLD were 6.46 +/- .90 pmol 5-HT/10(7) cells/min and 4.85 +/- 1.50 pmol 5-HT/10(7) cells/min, respectively. These values were both significantly higher than that of 2.25 +/- .97 pmole 5-HT/10(7) cells/min for normal children. The Km values of the three groups were not significantly different. Data on the five pairs of twins examined suggested that the elevated Vmax of 5-HT uptake by platelets was determined genetically.

  12. Association of cognitive distortions with problem and pathological gambling in adult male twins.

    PubMed

    Xian, Hong; Shah, Kamini R; Phillips, Sharon M; Scherrer, Jeffrey F; Volberg, Rachel; Eisen, Seth A

    2008-09-30

    Treatment studies suggest that gambling-related irrational beliefs and attitudes (i.e., cognitive distortions (CDs)) contribute to the risk for problem gambling behavior. In a community sample of men, we investigated the associations among lifetime gambling-related CDs, psychiatric disorders other than pathological gambling , and problem gambling severity. Subjects were 1354 members of the Vietnam Era Twin Registry. Problem gambling and gambling-related CDs were derived from a 2002 interview using the National Opinion Research Center DSM-IV Screen for Gambling Problems (NODS). Exploratory factor analysis was performed with the 12 CD items to identify an underlying construct. Generalized linear models were computed to test for associations among CDs, psychiatric disorders other than pathological gambling, and gambling problem severity. Co-twin control analyses of monozygotic twin pairs discordant for problem gambling severity adjusted for genetic and shared environmental influences. Twelve CD items related to one underlying CD construct. After adjustment for lifetime psychiatric disorders, pathological gambling symptoms were positively associated with higher CD scores. Pathological gambling symptoms remained significantly associated with CD scores after controlling for genetic and shared environmental influence. These results provide empirical support for an association between gambling-related CDs and gambling problem severity, even after controlling for genetic and shared environmental influences and non-pathological gambling psychiatric disorders. Public health messages and therapeutic interventions that reinforce the randomness of gambling and draw attention to distorted thinking may prevent the development of problem gambling and improve treatment outcomes.

  13. Attention Interchanges at Story-Time: A Case Study from a Deaf and Hearing Twin Pair Acquiring Swedish Sign Language in Their Deaf Family

    ERIC Educational Resources Information Center

    Cramer-Wolrath, Emelie

    2012-01-01

    This case study longitudinally analyzes and describes the changes of attentional expressions in interchanges between a pair of fraternal twins, 1 deaf and 1 hearing, from the age of 10-40 months, and their Deaf family members. The video-observed attentional expressions of initiating and reestablishing interchange were grouped in 5 functional…

  14. The effects of shared environment on adult intelligence: a critical review of adoption, twin, and MZA studies.

    PubMed

    Kaplan, Jack S

    2012-09-01

    There has been a vigorous debate for decades concerning the heritability of intelligence. In recent years, the debate has been focused on whether the components of IQ variability change with age and on separating environmental effects into shared and unshared components. Citing evidence from adoption studies, studies comparing identical and fraternal twins, and studies of identical twins raised apart, some prominent psychologists have concluded that the shared environment has a significant effect on the intelligence of children but little or no effect on the intelligence of adults. In this article, the evidence from such studies is reviewed. The article reaches the conclusion that while there is some evidence from adoption studies supporting the claim that shared environment has little or no effect on adult intelligence, that evidence is inconclusive and is inconsistent with evidence from twin studies and from studies of identical twins reared apart.

  15. The effects of shared environment on adult intelligence: a critical review of adoption, twin, and MZA studies.

    PubMed

    Kaplan, Jack S

    2012-09-01

    There has been a vigorous debate for decades concerning the heritability of intelligence. In recent years, the debate has been focused on whether the components of IQ variability change with age and on separating environmental effects into shared and unshared components. Citing evidence from adoption studies, studies comparing identical and fraternal twins, and studies of identical twins raised apart, some prominent psychologists have concluded that the shared environment has a significant effect on the intelligence of children but little or no effect on the intelligence of adults. In this article, the evidence from such studies is reviewed. The article reaches the conclusion that while there is some evidence from adoption studies supporting the claim that shared environment has little or no effect on adult intelligence, that evidence is inconclusive and is inconsistent with evidence from twin studies and from studies of identical twins reared apart. PMID:22746221

  16. Acral pseudolymphomatous angiokeratoma of children (APACHE)-like eruption in adult identical twins.

    PubMed

    Fonia, A; Bhatt, N; Robson, A; Kennedy, C T C

    2016-10-01

    Acral pseudolymphomatous angiokeratoma of children (APACHE) is a condition that was first described in 1990 in a group of children, but has since been described in adults. We present the cases of identical twin patients aged 40 years. The first brother presented with an 8-year history of itchy lesions over the left ankle and the insteps of both feet. After a diagnostic biopsy, he was treated with potent steroids under occlusion for 8 weeks, which resulted in flattening of the lesions and resolution of the pruritus. The second twin had a 20-year history of a very similar presentation but the lesions were less pronounced; he chose not to have treatment. No other family members were affected. Skin biopsies from both patients showed similar changes. Within an overall hyperkeratotic and acanthotic epidermis, there were focal areas of lichenoid change and epidermal thinning. Beneath these areas, there was oedema and nodular aggregates of dense inflammatory cell infiltrate, predominantly lymphocytic infiltrate. APACHE has not been previously described in twins. PMID:27663149

  17. Associations between sports participation, cardiorespiratory fitness, and adiposity in young adult twins.

    PubMed

    Mustelin, L; Latvala, A; Pietiläinen, K H; Piirilä, P; Sovijärvi, A R; Kujala, U M; Rissanen, A; Kaprio, J

    2011-03-01

    Exercise behavior, cardiorespiratory fitness, and obesity are strongly influenced by genetic factors. By studying young adult twins, we examined to what extent these interrelated traits have shared genetic and environmental etiologies. We studied 304 twin individuals selected from the population-based FinnTwin16 study. Physical activity was assessed with the Baecke questionnaire, yielding three indexes: sport index, leisure-time index, and work index. In this study, we focused on sport index, which describes sports participation. Body composition was determined using dual-energy X-ray absorptiometry and cardiorespiratory fitness using a bicycle ergometer exercise test with gas exchange analysis. The Baecke sport index was associated with high maximal oxygen uptake adjusted for lean body mass (Vo(2max)[adj]) (r = 0.40), with low body fat percentage (BF%) (r = -0.44) and low waist circumference (WC) (r = -0.29). Heritability estimates for the key traits were as follows: 56% for sport index, 71% for Vo(2max)[adj], 77% for body mass index, 66% for WC, and 68% for BF%. The association between sport index and Vo(2max) was mostly explained by genetic factors (70%), as were both the association between sport index and BF% (71%) and that between sport index and WC (59%). Our results suggest that genetic factors explain a considerable part of the associations between sports participation, cardiorespiratory fitness, and obesity.

  18. Why Accurate Knowledge of Zygosity is Important to Twins.

    PubMed

    Cutler, Tessa L; Murphy, Kate; Hopper, John L; Keogh, Louise A; Dai, Yun; Craig, Jeffrey M

    2015-06-01

    All same-sex dizygotic (DZ) twins and approximately one-third of monozygotic (MZ) twin pairs have separate placentas, making it impossible to use the number of placentas to determine zygosity. Zygosity determination is further complicated because incorrect assumptions are often made, such as that only DZ pairs have two placentas and that all MZ pairs are phenotypically identical. These assumptions, by twins, their families and health professionals, along with the lack of universal zygosity testing for same-sex twins, has led to confusion within the twin community, yet little research has been conducted with twins about their understanding and assumptions about zygosity. We aimed to explore and quantify understanding and assumptions about zygosity using twins attending an Australian twin festival. We recruited 91 twin pairs younger than 18 years of age and their parents, and 30 adult twin pairs who were all uncertain of their zygosity, to complete one pen and paper questionnaire and one online questionnaire about their assumed zygosity, reasons for their assumptions and the importance of accurate zygosity knowledge. Responses were compared with their true zygosity measured using a genetic test. We found a substantial proportion of parents and twins had been misinformed by their own parents or medical professionals, and that knowledge of their true zygosity status provided peace of mind and positive emotional responses. For these reasons we propose universal zygosity testing of same-sex twins as early in life as possible and an increase in education of medical professionals, twins and families of twins about zygosity issues. PMID:25851727

  19. Why Accurate Knowledge of Zygosity is Important to Twins.

    PubMed

    Cutler, Tessa L; Murphy, Kate; Hopper, John L; Keogh, Louise A; Dai, Yun; Craig, Jeffrey M

    2015-06-01

    All same-sex dizygotic (DZ) twins and approximately one-third of monozygotic (MZ) twin pairs have separate placentas, making it impossible to use the number of placentas to determine zygosity. Zygosity determination is further complicated because incorrect assumptions are often made, such as that only DZ pairs have two placentas and that all MZ pairs are phenotypically identical. These assumptions, by twins, their families and health professionals, along with the lack of universal zygosity testing for same-sex twins, has led to confusion within the twin community, yet little research has been conducted with twins about their understanding and assumptions about zygosity. We aimed to explore and quantify understanding and assumptions about zygosity using twins attending an Australian twin festival. We recruited 91 twin pairs younger than 18 years of age and their parents, and 30 adult twin pairs who were all uncertain of their zygosity, to complete one pen and paper questionnaire and one online questionnaire about their assumed zygosity, reasons for their assumptions and the importance of accurate zygosity knowledge. Responses were compared with their true zygosity measured using a genetic test. We found a substantial proportion of parents and twins had been misinformed by their own parents or medical professionals, and that knowledge of their true zygosity status provided peace of mind and positive emotional responses. For these reasons we propose universal zygosity testing of same-sex twins as early in life as possible and an increase in education of medical professionals, twins and families of twins about zygosity issues.

  20. Dietary Intake at 9 Years and Subsequent Body Mass Index in Adolescent Boys and Girls: A Study of Monozygotic Twin Pairs.

    PubMed

    Dubois, Lise; Diasparra, Maikol; Bogl, Leonie-Helen; Fontaine-Bisson, Bénédicte; Bédard, Brigitte; Tremblay, Richard E; Kaprio, Jaakko; Boivin, Michel

    2016-02-01

    There is a lack of evidence pointing to specific dietary elements related to weight gain and obesity prevention in childhood and adulthood. Dietary intake and obesity are both inherited and culturally transmitted, but most prospective studies on the association between diet and weight status do not take genetics into consideration. The objective of this study was to document the association between dietary intake at 9 years and subsequent Body Mass Index (BMI) in adolescent monozygotic boy and girl twin pairs. This research used data from 152 twin pairs. Dietary data were collected from two 24-hour-recall interviews with a parent and the child aged 9 years. Height and weight were obtained when the twins were aged 9, 12, 13, and 14 years. Intrapair variability analysis was performed to identify dietary elements related to BMI changes in subsequent years. BMI-discordant monozygotic twin pairs were also identified to analyze the dietary constituents that may have generated the discordance. After eliminating potential confounding genetic factors, pre-adolescent boys who ate fewer grain products and fruit and consumed more high-fat meat and milk had higher BMIs during adolescence; pre-adolescent girls who consumed more grain products and high-fat meat and milk had higher BMIs during adolescence. Energy intake (EI) at 9 years was not related to BMI in subsequent years. Our study suggests that messages and interventions directed at obesity prevention could take advantage of sex-specific designs and' eventually' genetic information.

  1. Dietary Intake at 9 Years and Subsequent Body Mass Index in Adolescent Boys and Girls: A Study of Monozygotic Twin Pairs.

    PubMed

    Dubois, Lise; Diasparra, Maikol; Bogl, Leonie-Helen; Fontaine-Bisson, Bénédicte; Bédard, Brigitte; Tremblay, Richard E; Kaprio, Jaakko; Boivin, Michel

    2016-02-01

    There is a lack of evidence pointing to specific dietary elements related to weight gain and obesity prevention in childhood and adulthood. Dietary intake and obesity are both inherited and culturally transmitted, but most prospective studies on the association between diet and weight status do not take genetics into consideration. The objective of this study was to document the association between dietary intake at 9 years and subsequent Body Mass Index (BMI) in adolescent monozygotic boy and girl twin pairs. This research used data from 152 twin pairs. Dietary data were collected from two 24-hour-recall interviews with a parent and the child aged 9 years. Height and weight were obtained when the twins were aged 9, 12, 13, and 14 years. Intrapair variability analysis was performed to identify dietary elements related to BMI changes in subsequent years. BMI-discordant monozygotic twin pairs were also identified to analyze the dietary constituents that may have generated the discordance. After eliminating potential confounding genetic factors, pre-adolescent boys who ate fewer grain products and fruit and consumed more high-fat meat and milk had higher BMIs during adolescence; pre-adolescent girls who consumed more grain products and high-fat meat and milk had higher BMIs during adolescence. Energy intake (EI) at 9 years was not related to BMI in subsequent years. Our study suggests that messages and interventions directed at obesity prevention could take advantage of sex-specific designs and' eventually' genetic information. PMID:26810866

  2. X-CHROMOSOME INACTIVATION PATTERNS IN MONOZYGOTIC TWINS AND SIB PAIRS DISCORDANT FOR NON-SYNDROMIC CLEFT LIP AND/OR PALATE

    PubMed Central

    Kimani, Jane W.; Shi, Min; Daack-Hirsch, Sandra; Christensen, Kaare; Moretti-Ferreira, Danilo; Marazita, Mary L.; Field, Leigh L.; Canady, John W.; Murray, Jeffrey C.

    2009-01-01

    Background Orofacial clefts are common birth defects with a complex etiology. While underlying mechanisms are still largely unknown, altered gender ratios for clefting phenotypes, evidence for linkage to the X chromosome and the occurrence of several X-linked clefting syndromes suggest that skewed X chromosome inactivation (XCI) may contribute to the etiology of orofacial clefting. We tested this hypothesis in a sample set of female monozygotic (MZ) twins and sister pairs discordant for clefting. Methods We determined XCI in peripheral blood lymphocyte DNA using a methylation based androgen receptor gene assay. We measured skewing of XCI as the deviation in XCI pattern from a 50:50 ratio and used a paired t-test to compare the degree of skewing in cases and their unaffected sisters. Results Our analysis revealed no significant difference in the degree of skewing between twin pairs (P=0.3). However, significant differences were observed in the sister pairs (P=0.02), with the cleft lip with cleft palate (CL+P) group showing the most significant result (P=0.01). Results from the cleft lip only (P=0.79) and cleft palate only (P=0.75) groups were not significant. Conclusions We did not find evidence for involvement of skewed XCI in the discordance for clefting in our sample of female MZ twins. However, results from the paired sister study suggest that skewed XCI may be important in orofacial clefting, particularly CL+P. PMID:18000982

  3. The Adult Netherlands Twin Register: Twenty-Five Years of Survey and Biological Data Collection

    PubMed Central

    Willemsen, Gonneke; Vink, Jacqueline M.; Abdellaoui, Abdel; den Braber, Anouk; van Beek, Jenny H. D. A.; Draisma, Harmen H. M.; van Dongen, Jenny; van ‘t Ent, Dennis; Geels, Lot M.; van Lien, Rene; Ligthart, Lannie; Kattenberg, Mathijs; Mbarek, Hamdi; de Moor, Marleen H. M.; Neijts, Melanie; Pool, Rene; Stroo, Natascha; Kluft, Cornelis; Suchiman, H. Eka D.; Slagboom, P. Eline; de Geus, Eco J. C.; Boomsma, Dorret I.

    2013-01-01

    Over the past 25 years, the Adult Netherlands Twin Register (ANTR) has collected a wealth of information on physical and mental health, lifestyle, and personality in adolescents and adults. This article provides an overview of the sources of information available, the main research findings, and an outlook for the future. Between 1991 and 2012, longitudinal surveys were completed by twins, their parents, siblings, spouses, and offspring. Data are available for 33,957 participants, with most individuals having completed two or more surveys. Smaller projects provided in-depth phenotyping, including measurements of the autonomic nervous system, neurocognitive function, and brain imaging. For 46% of the ANTR participants, DNA samples are available and whole genome scans have been obtained in more than 11,000 individuals. These data have resulted in numerous studies on heritability, gene × environment interactions, and causality, as well as gene finding studies. In the future, these studies will continue with collection of additional phenotypes, such as metabolomic and telomere length data, and detailed genetic information provided by DNA and RNA sequencing. Record linkage to national registers will allow the study of morbidity and mortality, thus providing insight into the development of health, lifestyle, and behavior across the lifespan. PMID:23298648

  4. Body mass index and subjective well-being in young adults: a twin population study

    PubMed Central

    2013-01-01

    Background Body mass index (BMI) is associated with subjective well-being. Higher BMI is believed to be related with lower well-being. However, the association may not be linear. Therefore, we investigated whether a nonlinear (U-shaped) trend would better describe this relationship, and whether eating disorders might account for the association in young adults. Methods FinnTwin16 study evaluated multiple measures of subjective well-being, including life satisfaction, General Health Questionnaire (GHQ-20), satisfaction with leisure time, work, and family relationships, and satisfaction with sex life in young adulthood in the 1975–79 birth cohorts of Finnish twins (n=5240). We studied the relationship between indicators of subjective well-being and BMI both in full birth cohorts and in subgroups stratified by lifetime DSM-IV eating disorders. Results We found an inverse U-shaped relationship between all indicators of subjective well-being and BMI in men. There was no overall association between BMI and subjective well-being in women. However, there was an inverse U-shaped relationship between BMI and indicators of subjective well-being in women with a lifetime eating disorder and their healthy female co-twins. Subjective well-being was optimal in the overweight category. Conclusions Both underweight and obesity are associated with impaired subjective well-being in young men. The BMI reflecting optimal subjective well-being of young men may be higher than currently recognized. Categorization of body weight in terms of BMI may need to be reassessed in young men. BMI and subjective well-being are related in women with a lifetime eating disorder, but not in the general population of young women. PMID:23496885

  5. Muscle dissatisfaction and muscle-enhancing substance use: a population-based twin study in young adult men.

    PubMed

    Raevuori, Anu; Keski-Rahkonen, Anna; Rose, Richard J; Rissanen, Aila; Kaprio, Jaakko

    2006-06-01

    In the population-based Finn Twin 16 study, proportions of genetic and environmental factors contributing to muscle dissatisfaction and muscle-enhancing substance use were assessed in 319 pairs of twin brothers: 141 monozygotic (MZ) and 178 dizygotic (DZ) pairs. In addition there were 86 twin individuals from pairs in which only one co-twin responded. Of all respondents, 30% experienced high muscle dissatisfaction. The corresponding proportion of muscle-enhancing substance use was 10%. The subjects were similar in age (23.8 years, 95% confidence interval [CI] 23.76-23.84), body mass index (23.7, 95% CI 23.5-23.9), and waist circumference (84.5 cm, 95% CI 83.7-85.2), independent of their muscle dissatisfaction or muscle-enhancing substance use status and independent of their zygosity. The MZ polychoric correlation for muscle dissatisfaction was .39 (95% CI .17-.58) and .27 for DZ pairs (95% CI .07-.46). The MZ tetrachoric correlation for muscle-enhancing substance use was .65 (95% CI .28-.87) and .56 for DZ pairs (95% CI .26-.78). The AE model, where additive genetic factors (A) accounted for 42% (95% CI .23-.59) and unique environmental factors (E) 58% (95% CI .41-.77) of the liability, provided the best fit for muscle dissatisfaction. The CE model, where common environmental factors (C) accounted for 60% (95% CI .37-.77) and unique environmental factors (E) 40% (95% CI .23-.63) of the liability, provided the best fit for muscle-enhancing substance use. Both genetic and unique (nonfamilial) environmental factors are involved in muscle dissatisfaction in the population. Nongenetic factors (both familial and nonfamilial) appear to best explain the use of muscle-enhancing substances.

  6. Twin Mitochondrial Sequence Analysis.

    PubMed

    Bouhlal, Yosr; Martinez, Selena; Gong, Henry; Dumas, Kevin; Shieh, Joseph T C

    2013-09-01

    When applying genome-wide sequencing technologies to disease investigation, it is increasingly important to resolve sequence variation in regions of the genome that may have homologous sequences. The human mitochondrial genome challenges interpretation given the potential for heteroplasmy, somatic variation, and homologous nuclear mitochondrial sequences (numts). Identical twins share the same mitochondrial DNA (mtDNA) from early life, but whether the mitochondrial sequence remains similar is unclear. We compared an adult monozygotic twin pair using high throughput-sequencing and evaluated variants with primer extension and mitochondrial pre-enrichment. Thirty-seven variants were shared between the twin individuals, and the variants were verified on the original genomic DNA. These studies support highly identical genetic sequence in this case. Certain low-level variant calls were of high quality and homology to the mitochondrial DNA, and they were further evaluated. When we assessed calls in pre-enriched mitochondrial DNA templates, we found that these may represent numts, which can be differentiated from mtDNA variation. We conclude that twin identity extends to mitochondrial DNA, and it is critical to differentiate between numts and mtDNA in genome sequencing, particularly since significant heteroplasmy could influence genome interpretation. Further studies on mtDNA and numts will aid in understanding how variation occurs and persists. PMID:24040623

  7. Nature and nurture: a case of transcending haematological pre-malignancies in a pair of monozygotic twins adding possible clues on the pathogenesis of B-cell proliferations.

    PubMed

    Hansen, Marcus C; Nyvold, Charlotte G; Roug, Anne S; Kjeldsen, Eigil; Villesen, Palle; Nederby, Line; Hokland, Peter

    2015-05-01

    We describe a comprehensive molecular analysis of a pair of monozygotic twins, who came to our attention when one experienced amaurosis fugax and was diagnosed with JAK2+ polycythaemia vera. He (Twin A) was also found to have an asymptomatic B-cell chronic lymphocytic leukaemia (B-CLL). Although JAK2-, Twin B was subsequently shown to have a benign monoclonal B-cell lymphocytosis (MBL). Flow cytometric and molecular analyses of the B-cell compartments revealed different immunoglobulin light and heavy chain usage in each twin. We hypothesized that whole exome sequencing could help delineating the pattern of germline B-cell disorder susceptibility and reveal somatic mutations potentially contributing to the differential patterns of pre-malignancy. Comparing bone marrow cells and T cells and employing in-house engineered integrative analysis, we found aberrations in Twin A consistent with a myeloid neoplasm, i.e. in TET2, RUNX1, PLCB1 and ELF4. Employing the method for detecting high-ranking variants by extensive annotation and relevance scoring, we also identified shared germline variants in genes of proteins interacting with B-cell receptor signalling mediators and the WNT-pathway, including IRF8, PTPRO, BCL9L, SIT1 and SIRPB1, all with possible implications in B-cell proliferation. Similar patterns of IGHV-gene usage to those demonstrated here have been observed in inherited acute lymphoblastic leukaemia. Collectively, these findings may help in facilitating identification of putative master gene(s) involved in B-cell proliferations in general and MBL and B-CLL in particular. PMID:25752595

  8. Nature and nurture: a case of transcending haematological pre-malignancies in a pair of monozygotic twins adding possible clues on the pathogenesis of B-cell proliferations.

    PubMed

    Hansen, Marcus C; Nyvold, Charlotte G; Roug, Anne S; Kjeldsen, Eigil; Villesen, Palle; Nederby, Line; Hokland, Peter

    2015-05-01

    We describe a comprehensive molecular analysis of a pair of monozygotic twins, who came to our attention when one experienced amaurosis fugax and was diagnosed with JAK2+ polycythaemia vera. He (Twin A) was also found to have an asymptomatic B-cell chronic lymphocytic leukaemia (B-CLL). Although JAK2-, Twin B was subsequently shown to have a benign monoclonal B-cell lymphocytosis (MBL). Flow cytometric and molecular analyses of the B-cell compartments revealed different immunoglobulin light and heavy chain usage in each twin. We hypothesized that whole exome sequencing could help delineating the pattern of germline B-cell disorder susceptibility and reveal somatic mutations potentially contributing to the differential patterns of pre-malignancy. Comparing bone marrow cells and T cells and employing in-house engineered integrative analysis, we found aberrations in Twin A consistent with a myeloid neoplasm, i.e. in TET2, RUNX1, PLCB1 and ELF4. Employing the method for detecting high-ranking variants by extensive annotation and relevance scoring, we also identified shared germline variants in genes of proteins interacting with B-cell receptor signalling mediators and the WNT-pathway, including IRF8, PTPRO, BCL9L, SIT1 and SIRPB1, all with possible implications in B-cell proliferation. Similar patterns of IGHV-gene usage to those demonstrated here have been observed in inherited acute lymphoblastic leukaemia. Collectively, these findings may help in facilitating identification of putative master gene(s) involved in B-cell proliferations in general and MBL and B-CLL in particular.

  9. Genetic and environmental contributions to pro-social attitudes: a twin study of social responsibility.

    PubMed

    Rushton, J Philippe

    2004-12-22

    Although 51 twin and adoption studies have been performed on the genetic architecture of antisocial behaviour, only four previous studies have examined a genetic contribution to pro-social behaviour. Earlier work by the author with the University of London Institute of Psychiatry Adult Twin Register found that genes contributed approximately half of the variance to measures of self-report altruism, empathy, nurturance and aggression, including acts of violence. The present study extends those results by using a 22-item Social Responsibility Questionnaire with 174 pairs of monozygotic twins and 148 pairs of dizygotic twins. Forty-two per cent of the reliable variance was due to the twins' genes, 23% to the twins' common environment and the remainder to the twins' non-shared environment.

  10. How Do Friends Influence Smoking Uptake? Findings from Qualitative Interviews with Identical Twins

    ERIC Educational Resources Information Center

    McLeod, Kim; White, Victoria; Mullins, Robyn; Davey, Claire; Wakefield, Melanie; Hill, David

    2008-01-01

    The smoking behavior of friends is a major risk factor for adolescent smoking uptake. To explore the social context of smoking experimentation and consolidation with a particular focus on friends, the authors interviewed both members of 14 young adult identical twin pairs who were discordant for smoking. The different smoking status of twins was…

  11. Mental Representations of Attachment in Identical Female Twins with and without Conduct Problems

    ERIC Educational Resources Information Center

    Constantino, John N.; Chackes, Laura M.; Wartner, Ulrike G.; Gross, Maggie; Brophy, Susan L.; Vitale, Josie; Heath, Andrew C.

    2006-01-01

    Insecure mental representations of attachment, a nearly invariant feature of cluster B personality disorders, have never previously been studied in twins. We conducted the Adult Attachment Interview (AAI) on 33 pairs of monozygotic (MZ) female twins reared together as an initial exploration of causal influences on mental representations of…

  12. Cross-sectional schooling-health associations misrepresented causal schooling effects on adult health and health-related behaviors: evidence from the Chinese Adults Twins Survey.

    PubMed

    Behrman, Jere R; Xiong, Yanyan; Zhang, Junsen

    2015-02-01

    Adult health outcomes and health behaviors are often associated with schooling. However, such associations do not necessarily imply that schooling has causal effects on health with the signs or magnitudes found in the cross-sectional associations. Schooling may be proxying for unobserved factors related to genetics and family background that directly affect both health and schooling. Recently several studies have used within-monozygotic (MZ) twins methods to control for unobserved factors shared by identical twins. Within-MZ estimates for developed countries are generally smaller than suggested by cross-sectional associations, consistent with positive correlations between unobserved factors that determine schooling and those that determine health. This study contributes new estimates of cross-sectional associations and within-MZ causal effects using the Chinese Adults Twins Survey, the first study of its type for developing countries. The cross-sectional estimates suggest that schooling is significantly associated with adult health-related behaviors (smoking, drinking, exercising) but not with own or spouse health outcomes (general health, mental health, overweight, chronic diseases). However, within-MZ-twins estimators change the estimates for approximately half of these health indicators, in one case declining in absolute magnitudes and becoming insignificant and in the other cases increasing in absolute magnitudes. Within-MZ estimates indicate significant pro-health effects for at least one of the indicators for own health (better mental health), own health-related behaviors (less smoking) and spouse health (less overweight). PMID:25464872

  13. Cross-sectional schooling-health associations misrepresented causal schooling effects on adult health and health-related behaviors: Evidence from the Chinese Adults Twins Survey

    PubMed Central

    Behrman, Jere R.; Xiong, Yanyan; Zhang, Junsen

    2015-01-01

    Adult health outcomes and health behaviors are often associated with schooling. However, such associations do not necessarily imply that schooling has causal effects on health with the signs or magnitudes found in the cross-sectional associations. Schooling may be proxying for unobserved factors related to genetics and family background that directly affect both health and schooling. Recently several studies have used within-monozygotic (MZ) twins methods to control for unobserved factors shared by identical twins. Within-MZ estimates for developed countries are generally smaller than suggested by cross-sectional associations, consistent with positive correlations between unobserved factors that determine schooling and those that determine health. This study contributes new estimates of cross-sectional associations and within-MZ causal effects using the Chinese Adults Twins Survey, the first study of its type for developing countries. The cross-sectional estimates suggest that schooling is significantly associated with adult health-related behaviors (smoking, drinking, exercising) but not with own or spouse health outcomes (general health, mental health, overweight, chronic diseases). However, within-MZ-twins estimators change the estimates for approximately half of these health indicators, in one case declining in absolute magnitudes and becoming insignificant and in the other cases increasing in absolute magnitudes. Within-MZ estimates indicate significant pro-health effects for at least one of the indicators for own health (better mental health), own health-related behaviors (less smoking) and spouse health (less overweight). PMID:25464872

  14. Heritability of the neural response to emotional pictures: evidence from ERPs in an adult twin sample

    PubMed Central

    Venables, Noah C.; Proudfit, Greg Hajcak; Patrick, Christopher J.

    2015-01-01

    Affect-modulated event-related potentials (ERPs) are increasingly used to study psychopathology and individual differences in emotion processing. Many have suggested that variation in these neural responses reflects genetically mediated risk. However, to date, no studies have demonstrated genetic contributions to affect-modulated ERPs. The present study therefore sought to examine the heritability of a range of ERPs elicited during affective picture viewing. One hundred and thirty monozygotic and 124 dizygotic twin pairs passively viewed 30 pleasant, 30 neutral and 30 unpleasant images for 6 s each. The early posterior negativity was scored for each subject; in addition, the P300/late positive potential (LPP) was scored in multiple time windows and sites. Results indicate that the centro-parietal P300 (occurring between 300 and 600 ms) is subject to substantial genetic contributions. Furthermore, variance in the P300 elicited by affective stimuli was moderately heritable even after controlling for the P300 elicited by neutral stimuli. Later and more frontal activation (i.e. between 1000 and 3000 ms) also showed evidence of heritablity. Early parietal, and perhaps later frontal portions of the P300/LPP complex, may therefore represent promising neurobehavioral markers of genetically influenced processing of emotional information. PMID:24795435

  15. Digit ratio (2D:4D) in twins: heritability estimates and evidence for a masculinized trait expression in women from opposite-sex pairs.

    PubMed

    Voracek, Martin; Dressler, Stefan G

    2007-02-01

    The second-to-fourth digit ratio (2D:4D) is sexually dimorphic in humans, such that men on average have a lower 2D:4D than women. This somatic trait has been proposed as a biomarker for the organizational (permanent) effects of prenatal testosterone on the brain and behavior. Over the past few years, an accumulating research program has shown 2D:4D to be related to a multitude of sex-dependent, hormonally influenced psychological and behavioral traits. The present study investigated the 2D:4D ratio of 44 men and 70 women from 36 identical and 21 fraternal twin pairs. Both basic and advanced approaches for estimating heritability concordantly suggested that the trait is substantially heritable. The best-fitting structural equation model indicated that the contributions to individual differences in 2D:4D are 81% additively genetic, 19% nonshared environmental, and 0% shared environmental. Supplemental analyses showed that, consistent with a prediction from sex-hormone transfer theory, women from opposite-sex fraternal twin pairs had significantly lower (more male-typical) 2D:4D than women from same-sex fraternal twin pairs. Directions for research are discussed, such as investigating possible influences of the sex chromosomes on the expression of 2D:4D. Further family studies will be needed to test whether the transmission mode of 2D:4D is consistent with X-linked or Y-linked inheritance. The study of sex chromosome aberrations should indicate whether the presence of additional X or Y chromosomes is associated with 2D:4D levels.

  16. Whole-exome sequencing in a family with a monozygotic twin pair concordant for autism spectrum disorder and a follow-up study.

    PubMed

    Egawa, Jun; Watanabe, Yuichiro; Sugimoto, Atsunori; Nunokawa, Ayako; Shibuya, Masako; Igeta, Hirofumi; Inoue, Emiko; Hoya, Satoshi; Orime, Naoki; Hayashi, Taketsugu; Sugiyama, Toshiro; Someya, Toshiyuki

    2015-09-30

    Two truncating variations (WDR90 V1125fs and EFCAB5 L1210fs), identified by whole-exome sequencing in a family with a monozygotic twin pair concordant for autism spectrum disorder (ASD), were not detected in 257 ASD patients, 677 schizophrenia patients or 667 controls in a follow-up study. Thus, these variations were exclusively identified in the family, suggesting that rare truncating variations may have a role in the genetic etiology of ASD, at least in a subset of ASD patients. PMID:26189338

  17. A monozygotic twin pair with β-thalassemia carrier status in a Dudh Kharia tribal family of Orissa

    PubMed Central

    Balgir, R. S.

    2007-01-01

    BACKGROUND: The β-thalassemia syndrome is a genetically inherited commonly encountered hematological disorder in the state of Orissa. It causes high degree of morbidity, mortality and fetal wastage in the poor vulnerable people. AIMS AND OBJECTIVES: There is an equal probability (50% chance) in every singleton pregnancy that a carrier parent of β-thalassemia major would either bear normal or carrier offspring, but not two offspring with carrier of β-thalassemia major genotype together. For the first time, a carrier parent of β-thalassemia major gene has born progeny (three daughters and a twin male offspring) with a carrier status of β-thalassemia major in Dudh Kharia tribal family studied from Sundargarh district of Orissa. MATERIALS AND METHODS: We screened randomly selected population of Dudh Kharia tribe from Sundargarh district of Orissa for hemoglobinopathies to assess the extent of the problem, design possible interventions and provide genetic counseling to them. A family with twin children was identified during screening in Lata Gaon in Bargaon block of Sundargarh district of Orissa for the above-mentioned study. Background information for this family such as name, age, sex, tribe, native place, reproductive history, family pedigree and clinical signs and symptoms were also recorded. Standardized genetic and hematological procedures and techniques were followed for analysis. RESULTS: Laboratory investigations for alkaline electrophoresis of blood lysate on cellulose acetate membrane showed raised hemoglobin A2 level in mother (Hb A2 = 5.3%), in three daughters (Hb A2 =6.5, 5.9, 5.5% in chronological and birth order), in two twin sons (Hb A2 =5.9% and 6.0%) and normal (Hb A2 = 3.3%) for father. Hence, all the children i.e., three daughters and two twin sons, including the mother were β-thalassemia carriers. Since all the hematological parameters i.e., red cell indices, G-6-PD enzyme activity, ABO and Rhesus blood groups and identical

  18. Suicidal Ideation, Depression, and Conduct Disorder in a Sample of Adolescent and Young Adult Twins

    ERIC Educational Resources Information Center

    Linker, Julie; Gillespie, Nathan A.; Maes, Hermine; Eaves, Lindon; Silberg, Judy L.

    2012-01-01

    The co-occurrence of suicidal ideation, depression, and conduct disturbance is likely explained in part by correlated genetic and environmental risk factors. Little is known about the specific nature of these associations. Structured interviews on 2,814 twins from the Virginia Twin Study of Adolescent Behavioral Development (VTSABD) and Young…

  19. The National Longitudinal Study of Adolescent to Adult Health (Add Health) sibling pairs genome-wide data.

    PubMed

    McQueen, Matthew B; Boardman, Jason D; Domingue, Benjamin W; Smolen, Andrew; Tabor, Joyce; Killeya-Jones, Ley; Halpern, Carolyn T; Whitsel, Eric A; Harris, Kathleen Mullan

    2015-01-01

    Here we provide a detailed description of the genome-wide information available on the National Longitudinal Study of Adolescent to Adult Health (Add Health) sibling pair subsample (Harris et al. in Twin Res Hum Genet 16:391-398, 2013). A total of 2,020 samples were genotyped (including duplicates) arising from 1946 Add Health individuals from the sibling pairs subsample. After various steps for quality control (QC) and quality assurance (QA), we have high quality genome-wide data available on 1,888 individuals. In this report, we first highlight the QC and QA steps that were taken to prune the data of poorly performing samples and genetic markers. We further estimate the pairwise biological relationships using genome-wide data and compare those estimates to the assumed relationships in Add Health. Additionally, using genome-wide data from known regional reference populations from Europe, West Africa, North and South America, Japan and China, we estimate the relative genetic ancestry of the respondents. Finally, rather than conducting a traditional cross-sectional genome-wide association study (GWAS) of body mass index (BMI), we opted to utilize the extensive publicly available genome-wide information to conduct a weighted GWAS of longitudinal BMI while accounting for both family and ethnic variation.

  20. Monozygotic Twinning.

    PubMed

    Benirschke, Kurt

    2013-03-01

    This article discusses pathologies found in monozygotic twinning. Detailed information is provided regarding the development during monozygotic twin formation: embryo development, twin-to-twin transfusion syndrome, acardiac twinning, vanishing twins, conjoined twins, and Beckwith-Weidmann syndrome twins. An algorithm describing the approach for identifying pathology in a placenta with multiple pregnancies is presented.

  1. Twinning rates in Tamilnadu.

    PubMed Central

    Rao, P S; Inbaraj, S G; Muthurathnam, S

    1983-01-01

    A prospective study of human reproduction was conducted in Tamilnadu State, South India, from 1969 to 1975. This paper reports twinning rates and relates these to maternal age, parity, and consanguinity. Birth weights and other dimensions at birth and infant mortality are also studied. The overall twinning rate was 1 in 115 births. Dizygotic twinning rates increased significantly with maternal age and parity. The measurements at birth for like-sexed twin pairs were lower than that of unlike-sexed, but the mortalities did not differ significantly. Twins, in general, had a several fold increase in mortality as compared with singletons. PMID:6886580

  2. A Pair of Identical Twins Discordant for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Differ in Physiological Parameters and Gut Microbiome Composition

    PubMed Central

    Giloteaux, Ludovic; Hanson, Maureen R.; Keller, Betsy A.

    2016-01-01

    Patient: Male, 34 Final Diagnosis: ME/CFS Symptoms: Exertion intolerance • loss of functional capacity • pain • severe fatigue Medication: — Clinical Procedure: Cardiopulmonary exercise test Specialty: Sports Medicine Objective: Unknown ethiology Background: Patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) present with profound fatigue, flu-like symptoms, pain, cognitive impairment, orthostatic intolerance, post-exertional malaise (PEM), and exacerbation of some or all of the baseline symptoms. Case Report: We report on a pair of 34-year-old monozygotic twins discordant for ME/CFS, with WELL, the non-affected twin, and ILL, the affected twin. Both twins performed a two-day cardiopulmonary exercise test (CPET), preand post-exercise blood samples were drawn, and both provided stool samples for biochemical and molecular analyses. At peak exertion for both CPETs, ILL presented lower VO2peak and peak workload compared to WELL. WELL demonstrated normal reproducibility of VO2@ventilatory/anaerobic threshold (VAT) during CPET2, whereas ILL experienced an abnormal reduction of 13% in VAT during CPET2. A normal rise in lactate dehydrogenase (LDH), creatine kinase (CK), adrenocorticotropic hormone (ACTH), cortisol, creatinine, and ferritin content was observed following exercise for both WELL and ILL at each CPET. ILL showed higher increases of resistin, soluble CD40 ligand (sCD40L), and soluble Fas ligand (sFasL) after exercise compared to WELL. The gut bacterial microbiome and virome were examined and revealed a lower microbial diversity in ILL compared to WELL, with fewer beneficial bacteria such as Faecalibacterium and Bifidobacterium, and an expansion of bacteriophages belonging to the tailed dsDNA Caudovirales order. Conclusions: Results suggest dysfunctional immune activation in ILL following exercise and that prokaryotic viruses may contribute to mucosal inflammation and bacterial dysbiosis. Therefore, a two-day CPET and molecular

  3. Longitudinal Investigation into Genetics in the Conservation of Metabolic Phenotypes in Danish and Chinese Twins.

    PubMed

    Li, Shuxia; Kyvik, Kirsten Ohm; Duan, Haiping; Zhang, Dongfeng; Pang, Zengchang; Hjelmborg, Jacob; Tan, Qihua; Kruse, Torben; Dalgård, Christine

    2016-01-01

    Longitudinal twin studies on long term conservation of individual metabolic phenotypes can help to explore the genetic and environmental basis in maintaining metabolic homeostasis and metabolic health. We performed a longitudinal twin study on 12 metabolic phenotypes from Danish twins followed up for 12 years and Chinese twins traced for 7 years. The study covered a relatively large sample of 502 pairs of Danish adult twins with a mean age at intake of 38 years and a total of 181 Chinese adult twin pairs with a mean baseline age of 39.5 years. Bivariate twin models were fitted to the longitudinal measurements taken at two time points (at baseline and follow-up) to estimate the genetic and environmental contributions to phenotype variation and correlation at and between the two time points. High genetic components in the regulation of intra-individual phenotype correlation or stability over time were estimated in both Danish (h2>0.75 except fasting blood glucose) and Chinese (h2>0.72 except blood pressure) twins; moderate to high genetic contribution to phenotype variation at the two time points were also estimated except for the low genetic regulation on glucose in Danish and on blood pressure in Chinese twins. Meanwhile the bivariate twin models estimated shared environmental contributions to the variance and covariance in fasting blood glucose in Danish twins, and in systolic and diastolic blood pressure, low and high density lipoprotein cholesterol in Chinese twins. Overall, our longitudinal twin study on long-term stability of metabolic phenotypes in Danish and Chinese twins identified a common pattern of high genetic control over phenotype conservation, and at the same time revealed population-specific patterns of genetic and common environmental regulation on the variance as well as covariance of glucose and blood pressure. PMID:27618179

  4. Longitudinal Investigation into Genetics in the Conservation of Metabolic Phenotypes in Danish and Chinese Twins

    PubMed Central

    Li, Shuxia; Duan, Haiping; Zhang, Dongfeng; Pang, Zengchang; Hjelmborg, Jacob; Tan, Qihua; Kruse, Torben; Dalgård, Christine

    2016-01-01

    Longitudinal twin studies on long term conservation of individual metabolic phenotypes can help to explore the genetic and environmental basis in maintaining metabolic homeostasis and metabolic health. We performed a longitudinal twin study on 12 metabolic phenotypes from Danish twins followed up for 12 years and Chinese twins traced for 7 years. The study covered a relatively large sample of 502 pairs of Danish adult twins with a mean age at intake of 38 years and a total of 181 Chinese adult twin pairs with a mean baseline age of 39.5 years. Bivariate twin models were fitted to the longitudinal measurements taken at two time points (at baseline and follow-up) to estimate the genetic and environmental contributions to phenotype variation and correlation at and between the two time points. High genetic components in the regulation of intra-individual phenotype correlation or stability over time were estimated in both Danish (h2>0.75 except fasting blood glucose) and Chinese (h2>0.72 except blood pressure) twins; moderate to high genetic contribution to phenotype variation at the two time points were also estimated except for the low genetic regulation on glucose in Danish and on blood pressure in Chinese twins. Meanwhile the bivariate twin models estimated shared environmental contributions to the variance and covariance in fasting blood glucose in Danish twins, and in systolic and diastolic blood pressure, low and high density lipoprotein cholesterol in Chinese twins. Overall, our longitudinal twin study on long-term stability of metabolic phenotypes in Danish and Chinese twins identified a common pattern of high genetic control over phenotype conservation, and at the same time revealed population-specific patterns of genetic and common environmental regulation on the variance as well as covariance of glucose and blood pressure. PMID:27618179

  5. Prevalence and heritability of skin picking in an adult community sample: a twin study.

    PubMed

    Monzani, Benedetta; Rijsdijk, Fruhling; Cherkas, Lynn; Harris, Juliette; Keuthen, Nancy; Mataix-Cols, David

    2012-07-01

    Skin-picking disorder (SPD) is a disabling psychiatric condition that can lead to skin damage and other medical complications. Epidemiological data is scarce and its causes are unknown. The present study examined the prevalence and heritability of skin-picking symptoms in a large sample of twins. A total of 2,518 twins completed a valid and reliable self-report measure of skin-picking behavior. The prevalence of clinically significant skin picking was established using empirically derived cut-offs. Twin modeling methods were employed to decompose the variance in the liability to skin picking into additive genetic and shared and non-shared environmental factors. A total of 1.2% of twins scored above the cut-off, indicative of clinically significant skin picking. All these participants were women. Univariate model-fitting analyses (female twins only, N = 2,191) showed that genetic factors accounted for approximately 40% (95% CI 19-58%) of the variance in skin picking, with non-shared environmental factors and measurement error accounting for the remaining variance (60% [95% CI 42-81%]). Shared environmental factors were negligible. It is concluded that pathological skin picking is relatively prevalent problem, particularly among women, and that it tends to run in families primarily due to genetic factors. Non-shared environmental factors are also likely to play an important role in its etiology. PMID:22619132

  6. The Role of Adolescent Nutrition and Physical Activity in the Prediction of Verbal Intelligence during Early Adulthood: A Genetically Informed Analysis of Twin Pairs

    PubMed Central

    Jackson, Dylan B.; Beaver, Kevin M.

    2015-01-01

    A large body of research has revealed that nutrition and physical activity influence brain functioning at various stages of the life course. Nevertheless, very few studies have explored whether diet and exercise influence verbal intelligence as youth transition from adolescence into young adulthood. Even fewer studies have explored the link between these health behaviors and verbal intelligence while accounting for genetic and environmental factors that are shared between siblings. Employing data from the National Longitudinal Study of Adolescent Health, the current study uses a sample of same-sex twin pairs to test whether youth who engage in poorer fitness and nutritional practices are significantly more likely to exhibit reduced verbal intelligence during young adulthood. The results suggests that, independent of the effects of genetic and shared environmental factors, a number of nutritional and exercise factors during adolescence influence verbal intelligence during adulthood. Limitations are noted and suggestions for future research are outlined. PMID:25568969

  7. The role of adolescent nutrition and physical activity in the prediction of verbal intelligence during early adulthood: a genetically informed analysis of twin pairs.

    PubMed

    Jackson, Dylan B; Beaver, Kevin M

    2015-01-05

    A large body of research has revealed that nutrition and physical activity influence brain functioning at various stages of the life course. Nevertheless, very few studies have explored whether diet and exercise influence verbal intelligence as youth transition from adolescence into young adulthood. Even fewer studies have explored the link between these health behaviors and verbal intelligence while accounting for genetic and environmental factors that are shared between siblings. Employing data from the National Longitudinal Study of Adolescent Health, the current study uses a sample of same-sex twin pairs to test whether youth who engage in poorer fitness and nutritional practices are significantly more likely to exhibit reduced verbal intelligence during young adulthood. The results suggests that, independent of the effects of genetic and shared environmental factors, a number of nutritional and exercise factors during adolescence influence verbal intelligence during adulthood. Limitations are noted and suggestions for future research are outlined.

  8. The role of adolescent nutrition and physical activity in the prediction of verbal intelligence during early adulthood: a genetically informed analysis of twin pairs.

    PubMed

    Jackson, Dylan B; Beaver, Kevin M

    2015-01-01

    A large body of research has revealed that nutrition and physical activity influence brain functioning at various stages of the life course. Nevertheless, very few studies have explored whether diet and exercise influence verbal intelligence as youth transition from adolescence into young adulthood. Even fewer studies have explored the link between these health behaviors and verbal intelligence while accounting for genetic and environmental factors that are shared between siblings. Employing data from the National Longitudinal Study of Adolescent Health, the current study uses a sample of same-sex twin pairs to test whether youth who engage in poorer fitness and nutritional practices are significantly more likely to exhibit reduced verbal intelligence during young adulthood. The results suggests that, independent of the effects of genetic and shared environmental factors, a number of nutritional and exercise factors during adolescence influence verbal intelligence during adulthood. Limitations are noted and suggestions for future research are outlined. PMID:25568969

  9. Genetic and Environmental Influences on Two Measures of Speed of Information Processing and Their Relation to Psychometric Intelligence: Evidence from the German Observational Study of Adult Twins.

    ERIC Educational Resources Information Center

    Neubauer, Alioscha C.; Spinath, Frank M.; Riemann, Rainer; Angleitner, Alois; Borkenau, Peter

    2000-01-01

    Administered 2 elementary cognitive task (ECT) tests and 2 psychometric intelligence tests to 169 monozygotic and 131 dizygotic pairs of twins in Germany. Reaction times correlated negatively with psychometric intelligence, and habitability estimates were substantial for both psychometric intelligence and reaction times on the ECTs. Multivariate…

  10. Lifetime medical and psychiatric comorbidity of night eating behavior in the Swedish Twin Study of Adults: Genes and Environment (STAGE).

    PubMed

    Lundgren, Jennifer D; Allison, Kelly C; Stunkard, Albert J; Bulik, Cynthia M; Thornton, Laura M; Karin Lindroos, Anna; Rasmussen, Finn

    2012-09-30

    The medical and psychosocial comorbidity of two core features of night eating syndrome (NES), evening hyperphagia (EH) and nocturnal awakening and ingestion of food (NI), was evaluated in adults enrolled in the Swedish Twin Study of Adults: Genes and Environment (STAGE) study. As part of the STAGE study, more than 20,000 participants completed assessments of their physical and mental health, which included two night eating screening questions designed to assess EH and NI. STAGE participants who completed a night eating validation interview to confirm the presence or absence of night eating and who had comorbidity data available (n=463) were compared on the lifetime prevalence of several psychiatric and medical conditions. In contrast to previous studies, night eating (EH and/or NI) was not significantly associated with lifetime history of any mental or physical health variable.

  11. Lifetime medical and psychiatric comorbidity of night eating behavior in the Swedish Twin Study of Adults: Genes and Environment (STAGE).

    PubMed

    Lundgren, Jennifer D; Allison, Kelly C; Stunkard, Albert J; Bulik, Cynthia M; Thornton, Laura M; Karin Lindroos, Anna; Rasmussen, Finn

    2012-09-30

    The medical and psychosocial comorbidity of two core features of night eating syndrome (NES), evening hyperphagia (EH) and nocturnal awakening and ingestion of food (NI), was evaluated in adults enrolled in the Swedish Twin Study of Adults: Genes and Environment (STAGE) study. As part of the STAGE study, more than 20,000 participants completed assessments of their physical and mental health, which included two night eating screening questions designed to assess EH and NI. STAGE participants who completed a night eating validation interview to confirm the presence or absence of night eating and who had comorbidity data available (n=463) were compared on the lifetime prevalence of several psychiatric and medical conditions. In contrast to previous studies, night eating (EH and/or NI) was not significantly associated with lifetime history of any mental or physical health variable. PMID:22560060

  12. Language Difference between Twins and Singletons - Biological, Environmental, or Both?

    ERIC Educational Resources Information Center

    Conway, Dorice; Lytton, Hugh

    This data compared language complexity measures, birth information, and family data for twins and singletons of the same sex, age, and socio-economic status. The subjects were four pairs of male twins, four pairs of female twins, four pairs of opposite sex twins, and 24 singletons, 32-33 months of age. Samples of each child's spontaneous…

  13. Mitochondrial DNA heteroplasmy in diabetes and normal adults: role of acquired and inherited mutational patterns in twins

    PubMed Central

    Avital, Gal; Buchshtav, Mor; Zhidkov, Ilia; Tuval (Feder), Jeanette; Dadon, Sarah; Rubin, Eitan; Glass, Dan; Spector, Timothy D.; Mishmar, Dan

    2012-01-01

    Heteroplasmy, the mixture of mitochondrial genomes (mtDNA), varies among individuals and cells. Heteroplasmy levels alter the penetrance of pathological mtDNA mutations, and the susceptibility to age-related diseases such as Parkinson's disease. Although mitochondrial dysfunction occurs in age-related type 2 diabetes mellitus (T2DM), the involvement of heteroplasmy in diabetes is unclear. We hypothesized that the heteroplasmic mutational (HM) pattern may change in T2DM. To test this, we used next-generation sequencing, i.e. massive parallel sequencing (MPS), along with PCR–cloning–Sanger sequencing to analyze HM in blood and skeletal muscle DNA samples from monozygotic (MZ) twins either concordant or discordant for T2DM. Great variability was identified in the repertoires and amounts of HMs among individuals, with a tendency towards more mutations in skeletal muscle than in blood. Whereas many HMs were unique, many were either shared among twin pairs or among tissues of the same individual, regardless of their prevalence. This suggested a heritable influence on even low abundance HMs. We found no clear differences between T2DM and controls. However, we found ∼5-fold increase of HMs in non-coding sequences implying the influence of negative selection (P < 0.001). This negative selection was evident both in moderate to highly abundant heteroplasmy (>5% of the molecules per sample) and in low abundance heteroplasmy (<5% of the molecules). Although our study found no evidence supporting the involvement of HMs in the etiology of T2DM, the twin study found clear evidence of a heritable influence on the accumulation of HMs as well as the signatures of selection in heteroplasmic mutations. PMID:22736028

  14. Mitochondrial DNA heteroplasmy in diabetes and normal adults: role of acquired and inherited mutational patterns in twins.

    PubMed

    Avital, Gal; Buchshtav, Mor; Zhidkov, Ilia; Tuval Feder, Jeanette; Dadon, Sarah; Rubin, Eitan; Glass, Dan; Spector, Timothy D; Mishmar, Dan

    2012-10-01

    Heteroplasmy, the mixture of mitochondrial genomes (mtDNA), varies among individuals and cells. Heteroplasmy levels alter the penetrance of pathological mtDNA mutations, and the susceptibility to age-related diseases such as Parkinson's disease. Although mitochondrial dysfunction occurs in age-related type 2 diabetes mellitus (T2DM), the involvement of heteroplasmy in diabetes is unclear. We hypothesized that the heteroplasmic mutational (HM) pattern may change in T2DM. To test this, we used next-generation sequencing, i.e. massive parallel sequencing (MPS), along with PCR-cloning-Sanger sequencing to analyze HM in blood and skeletal muscle DNA samples from monozygotic (MZ) twins either concordant or discordant for T2DM. Great variability was identified in the repertoires and amounts of HMs among individuals, with a tendency towards more mutations in skeletal muscle than in blood. Whereas many HMs were unique, many were either shared among twin pairs or among tissues of the same individual, regardless of their prevalence. This suggested a heritable influence on even low abundance HMs. We found no clear differences between T2DM and controls. However, we found ~5-fold increase of HMs in non-coding sequences implying the influence of negative selection (P < 0.001). This negative selection was evident both in moderate to highly abundant heteroplasmy (>5% of the molecules per sample) and in low abundance heteroplasmy (<5% of the molecules). Although our study found no evidence supporting the involvement of HMs in the etiology of T2DM, the twin study found clear evidence of a heritable influence on the accumulation of HMs as well as the signatures of selection in heteroplasmic mutations.

  15. Production of the Higgs boson associated with a top quark pair in the left-right twin Higgs model

    NASA Astrophysics Data System (ADS)

    Shen, Jie-Fen; Cao, Jun; Yan, Lei-Bing

    2010-09-01

    In the left-right twin Higgs (LRTH) model, we first examine the effects on the t\\bar{t}h production at the ILC and LHC. Our results show that in the allowed parameter space, the absolute values of the relative correction can be significantly large and thus provide a good test for the LRTH model. We also estimate the new production channel of t\\bar{T}h or T\\bar{t}h at the LHC and find that, with reasonable parameter values of the LRTH model, the values of the total hadronic cross-section can reach the level of 102 fb. The dominant decay mode T\\rightarrow \\phi^{+}b \\rightarrow t\\bar{b}b , with h\\rightarrow b\\bar{b} (or h→W+W-) can make the processes pp\\rightarrow t\\bar{T}h+T\\bar{t}h give rise to the t\\bar{t}bb\\bar{b}\\bar{b} (or t\\bar{t}bbW^{+}W^{-} ) final state, which has less background than ht\\bar{t} production, and thus this new channel may likely be observable at the LHC.

  16. The Western Australian Twin Register: a population-based register of adult and child multiples.

    PubMed

    Lee, Jessica D Y; Palmer, Lyle J

    2006-12-01

    The Western Australian Twin Register (WATR) was established in 1997 to study the health of all child multiples born in Western Australia (WA). The Register has until recently consisted of all multiples born in WA between 1980 and 1997. Using unique record linkage capacities available through the WA data linkage system, we have subsequently been able to identify all multiple births born in WA since 1974. New affiliations with the Australian Twin Registry and the WA Institute for Medical Research are further enabled by the use of the WA Genetic Epidemiology Resource--a high-end bioinformatics infrastructure that allows efficient management of health datasets and facilitates collaborative research capabilities. In addition to this infrastructure, funding provided by these institutions has allowed the extension of the WATR to include a greater number of WA multiples, including those born between 1974 and 1979, and from 1998 onwards. These resources are in the process of being enabled for national and international access.

  17. SuperQuads: a day in the life; research reviews: color-number association, finger-length ratios, twinning diets, athletic pairs.

    PubMed

    Segal, Nancy L

    2006-08-01

    The nature and frequency of quadruplet births are reviewed, followed by a close-up look at the 6-year-old monozygotic Mathias quadruplets. This essay is followed by reviews of new twin research on color-number association, male-female twins' finger-length ratios, and links between twinning and dietary practices. The article finishes by focusing on unusual twin athletes in football, basketball and golf, and on twin co-authors of a new book on the 1972 silver medal victory by the United States hockey team.

  18. Heritability of Renal Function and Inflammatory Markers in Adult Male Twins

    PubMed Central

    Raggi, Paolo; Su, Shaoyong; Karohl, Cristina; Veledar, Emir; Rojas-Campos, Enrique; Vaccarino, Viola

    2010-01-01

    Background Loss of renal function is accompanied by a progressive increase in markers of inflammation; it is unknown whether they share common genetic pathways. Study Design We evaluated the shared heritability of estimated glomerular filtration rate (eGFR) and markers of inflammation and endothelial activation in 524 twin males from the Vietnam Era Twin Registry; 9 twins were excluded due to incomplete or incorrect data. Models were adjusted for age, race, body mass index, smoking, hypertension, diabetes mellitus, prior coronary artery disease and intercurrent medications. Results The mean eGFR was 89 ± 13 ml/min/1.73 m2 (range 35–146); eGFR, intracellular adhesion molecule (ICAM) and TNF-α receptor (TNF-αR) were moderately heritable (all ∼50%), while IL-6 receptor (IL-6R) and P-selectin were highly heritable (68 and 76%, respectively). IL-6R and TNF-αR showed a significant inverse association with eGFR (p = 0.04 and p < 0.0001) while the association with ICAM and P-selectin was direct (p = 0.001 and p = 0.06). Bivariate structural equation models showed that the association between eGFR and biomarkers was due to unique environmental factors and there were no shared genetic pathways. Conclusion We found no shared genetic pathways between renal function and inflammation. Thus, increased inflammation represents a response to declining renal function rather than being a mechanism contributing to renal deterioration. PMID:20720405

  19. Reflections on twin relationships: twins reared apart and twins of opposite gender.

    PubMed

    Segal, Nancy L

    2012-12-01

    The complexities of twin relationships posed by separate rearing and by opposite sex are considered. Unusual cases may highlight unique social-interactional processes and outcomes occurring in these pairs. Research reviews include recent twin studies on second language acquisition, political behavior, and multiple birth rates. Items of more general interest include twin 'cousins' reared apart, indistinguishable monozygotic quadruplets, a genetic testing dilemma, and a performance about separated twins. PMID:23363461

  20. Twin classics: research that always inspires/Twin studies: elder twin relationships; Superfecundated twinning in chimpanzees; Conjoined twinning and embryo transfer; Reduced frequency of in vitro multiples/Professional and human interest: first identical twin renal transplant; Identical triplet wedding; Spanakos twins: boxers; Twins in space; Political twins.

    PubMed

    Segal, Nancy L

    2015-08-01

    Ten classic works in twin research are described. These volumes are rich in data, interpretation, and impact, and contain life history material that adds depth and dimension to the quantitative findings. Next, research on social relationships in older twins, superfecundated twinning in chimpanzees; effects of embryo transfer on conjoined twinning and the reduced frequency of in vitro multiples is reviewed. Finally, there has been considerable public interest surrounding the first identical twin renal transplant, an identical triplet wedding; identical twin boxers, a twin living in space, and a politically active twin pair. PMID:26148718

  1. Twin classics: research that always inspires/Twin studies: elder twin relationships; Superfecundated twinning in chimpanzees; Conjoined twinning and embryo transfer; Reduced frequency of in vitro multiples/Professional and human interest: first identical twin renal transplant; Identical triplet wedding; Spanakos twins: boxers; Twins in space; Political twins.

    PubMed

    Segal, Nancy L

    2015-08-01

    Ten classic works in twin research are described. These volumes are rich in data, interpretation, and impact, and contain life history material that adds depth and dimension to the quantitative findings. Next, research on social relationships in older twins, superfecundated twinning in chimpanzees; effects of embryo transfer on conjoined twinning and the reduced frequency of in vitro multiples is reviewed. Finally, there has been considerable public interest surrounding the first identical twin renal transplant, an identical triplet wedding; identical twin boxers, a twin living in space, and a politically active twin pair.

  2. Malaysian Twin Registry.

    PubMed

    Jahanfar, Shayesteh; Jaffar, Sharifah Halimah

    2013-02-01

    The National Malaysian Twin Registry was established in Royal College of Medicine, Perak, University Kuala Lumpur (UniKL) in June 2008 through a grant provided by UniKL. The general objective is to facilitate scientific research involving participation of twins and their family members in order to answer questions of health and wellbeing relevant to Malaysians. Recruitment is done via mass media, poster, and pamphlets. We now have 266 adult and 204 children twins registered. Several research projects including reproductive health study of twins and the role of co-bedding on growth and development of children are carried out. Registry holds annual activities for twins and seeks to provide health-related information for twins. We seek international collaboration.

  3. Monozygotic VS. Dizygotic Twin Behavior in Artificial Mouse Twins

    PubMed Central

    Baunack, E.; Falk, U.; Gärtner, K.

    1984-01-01

    Adult inbred mice of an isogenic strain (AKR/NHan or C57BL/6J Han) differ in social (sexual and agonistic), emotional and psychomotoric behavior, depending on the kind of manipulation to which they were subjected at an early ontogenetic stage. Monozygotic twins (MZT) from eight-cell stages halved and transferred to uterine foster mothers were compared with dizygotic twins (DZT) from nonreduced but transferred eight-cell stages and with naturally born animals (NBA). Generally, early embryonic conditions predict the behavioral characteristics of the adult animals to a high degree. The MZT are motorially less active, less emotional, less aggressive and less socially interested than DZT and NBA. In tests of spontaneous social behavior (allogrooming, anogenital licking, mounting, fighting), as well as in tests for emotionality (open field: crossed fields and defecation), these behavioral patterns occurred less frequently in MZT than in DZT; the NBA were mostly intermediate. The copulatory pattern of male MZT differs from that of male DZT by a shortage of intromission latency and duration; furthermore, MZT pairs do not build up a steady rank order in competitive copulation tests, as opposed to DZT and NBA pairs. In a test for psychomotoric behavior (swimming), the MZT prefer "floating" as a survival strategy, wheras the DZT and NBA prefer "adult swimming." Therefore, it can be concluded that these behavioral differences may be caused by the particular psychosocial environment in which the twins grow up or may be due to early prenatal peculiarities, such as inadequate synchronization of the developmental status of uterus and embryo. PMID:6538528

  4. Further studies on in vitro pairing of Echinostoma revolutum (Trematoda) adults.

    PubMed

    Fried, B; Pallone, A

    1984-01-01

    Various factors that influence in vitro pairing of Echinostoma revolutum adults were studied. More worms paired in Locke's, Ringer's, and 0.85% NaCl solutions than in the defined medium NCTC 135. Also, more pairing occurred at 39 or 43 degrees C than at 35 degrees C. Echinostomes placed 1, 3, or 5 cm apart in 5.5 cm diameter Petri dishes as well as those placed 2, 4, or 6 cm apart in 8.5 cm diameter Petri dishes paired; however, worms placed 8 cm apart in the latter dishes did not. Individuals maintained in Locke's solution at 20 or 39 degrees C for 1 h after having been removed from the chicks paired less frequently than those used for experiments immediately after their removal from chicks. Worms showed more pairing in fresh Locke's solution than in this solution preconditioned by excretory-secretory products of E. revolutum. Scanning electron microscopy revealed no differences between the tegument of fresh worms and of those maintained under experimental conditions for 2 h at 39 degrees C. PMID:6741219

  5. The red dwarf pair GJ65 AB: inflated, spinning twins of Proxima. Fundamental parameters from PIONIER, NACO, and UVES observations

    NASA Astrophysics Data System (ADS)

    Kervella, P.; Mérand, A.; Ledoux, C.; Demory, B.-O.; Le Bouquin, J.-B.

    2016-10-01

    The nearby red dwarf binary GJ65 AB (UV+BL Ceti, M5.5Ve+M6Ve) is a cornerstone system to probe the physics of very low-mass stars. The radii of the two stars are currently known only from indirect photometric estimates, however, and this prevents us from using GJ65 AB as calibrators for the mass-radius (M-R) relation. We present new interferometric measurements of the angular diameters of the two components of GJ65 with the VLTI/PIONIER instrument in the near-infrared H band: θUD(A) = 0.558 ± 0.008 ± 0.020 mas and θUD(B) = 0.539 ± 0.009 ± 0.020 mas. They translate into limb-darkened angular diameters of θLD(A) = 0.573 ± 0.021 mas and θLD(B) = 0.554 ± 0.022 mas. Based on the known parallax, the linear radii are R(A) = 0.165 ± 0.006 R⊙ and R(B) = 0.159 ± 0.006 R⊙ (σ(R) /R = 4%). We searched for the signature of flares and faint companions in the interferometric visibilities and closure phases, but we did not identify any significant signal. We also observed GJ65 with the VLT/NACO adaptive optics and refined the orbital parameters and infrared magnitudes of the system. We derived masses for the two components of m(A) = 0.1225 ± 0.0043 M⊙ and m(B) = 0.1195 ± 0.0043 M⊙ (σ(m) /m = 4%). To derive the radial and rotational velocities of the two stars as well as their relative metallicity with respect to Proxima, we also present new individual UVES high-resolution spectra of the two components. Placing GJ65 A and B in the mass-radius diagram shows that their radii exceed expectations from recent models by 14 ± 4% and 12 ± 4%, respectively. Following previous theories, we propose that this discrepancy is caused by the inhibition of convective energy transport by a strong internal magnetic field generated by dynamo effect in these two fast-rotating stars. A comparison with the almost identical twin Proxima, which is rotating slowly, strengthens this hypothesis because the radius of Proxima does not appear to be inflated compared to models. Based on

  6. The Murcia Twin Registry: a population-based registry of adult multiples in Spain.

    PubMed

    Ordoñana, Juan R; Rebollo-Mesa, Irene; Carrillo, Eduvigis; Colodro-Conde, Lucía; García-Palomo, Francisco J; González-Javier, Francisca; Sánchez-Romera, Juan F; Aznar Oviedo, José M; de Pancorbo, Marian M; Pérez-Riquelme, Francisco

    2013-02-01

    The Murcia Twin Registry (MTR) was created in 2006, under the auspices of the University of Murcia and the regional Health Authority, aiming to develop a research resource in Spain intended to stimulate current research and new investigation on the analysis of genetic factors related to health and health-related behaviors. The MTR development strategy was designed as a step-by-step process. Initially, it was focused on women's health but nowadays it includes males and opposite-sex twins. The database comprises 2,281 participants born between 1940 and 1966 in the region of Murcia, in Spain. There have been three waves of data collection and today the MTR databases include questionnaire and anthropometric data as well as biological samples. The current main areas of research interest are health and health-related behaviors, including lifestyle, health promotion, and quality of life. Future short-term development points to the completion of the biobank and continuing the collection of longitudinal data.

  7. Dramatically different dizygotic twins: will we include them in Research? Twin research reviews: congenital anomalies, mirror-image effects in conjoined twins, older mothers of twins; Twin statistics: 'Massachusetts, land of twins'; Tribute: Dr Victor A. McKusick.

    PubMed

    Segal, Nancy L

    2008-10-01

    The increased frequency of interracial marriage is a likely source of unusual-looking dizygotic (DZ) twins. Some members of DZ twin pairs born to mixed-race couples inherit very different physical features from their parents. This raises several questions, such as: Will researchers wish to include such twins in their ongoing studies? Next, new twin research concerned with congenital anomalies, mirror-image effects in conjoined twins and older mothers of twins will be reviewed. New statistics on twinning rates in Massachusetts will also be summarized, followed by a tribute to the late medical geneticist Dr. Victor A. McKusick.

  8. Schooling has smaller or insignificant effects on adult health in the US than suggested by cross-sectional associations: new estimates using relatively large samples of identical twins.

    PubMed

    Amin, Vikesh; Behrman, Jere R; Kohler, Hans-Peter

    2015-02-01

    Numerous theoretical reasons have been posited about why more schooling might improve health. Adult health outcomes and behaviors generally are significantly associated with schooling. However, such associations do not necessarily imply that schooling has causal effects on health outcomes and behaviors. Causal estimates based on schooling variation from policies and from within-MZ (monozygotic) twins have reached mixed conclusions. This study contributed new estimates of cross-sectional associations and within-MZ causal effects using three relatively large US twins samples. The estimates suggested that schooling was significantly associated with numerous health outcomes and behaviors. However, with within-MZ twins control for unobserved factors, schooling was no longer associated with most indicators of better health (with the exception of self-reported health), while it continued to be associated with outcomes such as fertility and spousal schooling. Similar patterns were observed for spousal schooling. PMID:25110343

  9. Sleep characteristics in twins.

    PubMed

    Hori, A

    1986-03-01

    Polysomnograms were recorded for three consecutive nights on 14 male students (mean age, 16), comprising 4 identical and 3 fraternal twin pairs. The number of body movements and the measures related to the REM cycle, which correlated among the identical twins without reference to the physical parameters, were considered to be determined by a genetic trait. The sleep spindle density was in almost complete concordance between the identical twins and was associated with some physical parameters, which suggests that sleep spindles rather reflect the individual development. %S3, %SREM and the number of SREM showed a relationship to the physical parameters, without heritability. Twitch movements during REM sleep correlated not only between the identical twins but also between the fraternal twins.

  10. A Computational Discriminability Analysis on Twin Fingerprints

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Srihari, Sargur N.

    Sharing similar genetic traits makes the investigation of twins an important study in forensics and biometrics. Fingerprints are one of the most commonly found types of forensic evidence. The similarity between twins’ prints is critical establish to the reliability of fingerprint identification. We present a quantitative analysis of the discriminability of twin fingerprints on a new data set (227 pairs of identical twins and fraternal twins) recently collected from a twin population using both level 1 and level 2 features. Although the patterns of minutiae among twins are more similar than in the general population, the similarity of fingerprints of twins is significantly different from that between genuine prints of the same finger. Twins fingerprints are discriminable with a 1.5%~1.7% higher EER than non-twins. And identical twins can be distinguished by examine fingerprint with a slightly higher error rate than fraternal twins.

  11. Monozygotic twins discordant for sex.

    PubMed Central

    Schmidt, R; Sobel, E H; Nitowsky, H M; Dar, H; Allen, F H

    1976-01-01

    A pair of monozygotic, adolescent twins is discordant for sex. The phenotypic female twin has chromosome constitution of 46, XY/45, X. She displays many signs of Turner's syndrome, including typical facies, webbed neck, malformed left kidney, high plasma gonadotropins, and streak ovaries. However, her height is 154 cm which exceeds the height usually reported in Turner's syndrome. The male twin has a karyotype of 46, XY and normal sexual development. Only two other reports of pairs of monozygotic twins of opposite sex have been published. Images PMID:944787

  12. Genetic, epigenetic, and environmental influences on dentofacial structures and oral health: ongoing studies of Australian twins and their families.

    PubMed

    Hughes, Toby; Bockmann, Michelle; Mihailidis, Suzanna; Bennett, Corinna; Harris, Abbe; Seow, W Kim; Lekkas, Dimitra; Ranjitkar, Sarbin; Rupinskas, Loreta; Pinkerton, Sandra; Brook, Alan; Smith, Richard; Townsend, Grant C

    2013-02-01

    The Craniofacial Biology Research Group in the School of Dentistry at The University of Adelaide is entering an exciting new phase of its studies of dental development and oral health in twins and their families. Studies of the teeth and faces of Australian twins have been continuing for nearly 30 years, with three major cohorts of twins recruited over that time, and currently we are working with twins aged 2 years old to adults. Cross-sectional data and records relating to teeth and faces of twins are available for around 300 pairs of teenage twins, as well as longitudinal data for 300 pairs of twins examined at three different stages of development, once with primary teeth, once at the mixed dentition stage, and then again when the permanent teeth had emerged. The third cohort of twins comprises over 600 pairs of twins recruited at around birth, together with other family members. The emphasis in this third group of twins has been to record the timing of emergence of the primary teeth and also to sample saliva and dental plaque to establish the timing of colonization of decay-forming bacteria in the mouth. Analyses have confirmed that genetic factors strongly influence variation in timing of primary tooth emergence. The research team is now beginning to carry out clinical examinations of the twins to see whether those who become colonized earlier with decay-forming bacteria develop dental decay at an earlier age. By making comparisons within and between monozygotic (MZ) and dizygotic (DZ) twin pairs and applying modern molecular approaches, we are now teasing out how genetic, epigenetic, and environmental factors interact to influence dental development and also oral health.

  13. Twins' reactions to delayed auditory feedback.

    PubMed

    Timmons, B A

    1985-10-01

    10 pairs of identical and 10 pairs of fraternal twins, matched by age, spoke under conditions of 0.0-, 100-, 200-, 300-, 400-, and 500-msec. delayed auditory feedback. Length of spoken passages was controlled. Product-moment and intraclass correlations were calculated for speaking times and disfluencies. Significant Pearson rs for times were noted at 0.0 and 300 msec. for both groups and at 100, 200, and 400 msec. for identical twins, while fraternal twins' times were significantly correlated at 500 msec. Difference scores were significantly correlated at 100, 200, 300, and 400 msec. for identical twins. Disfluencies were significantly correlated for identical twins at 400 msec. Data were combined with those of Timmons' (1969) study, increasing subjects to 21 pairs per group. Intraclass correlations supported the contention that responses of identical twin pairs to delayed auditory feedback were more highly correlated than those for fraternal twin pairs.

  14. In vitro pairing of Echinostoma revolutum (trematoda) metacercariae and adults, and characterization of worm products involved in chemoattraction.

    PubMed

    Fried, B; Tancer, R B; Fleming, S J

    1980-12-01

    In vitro pairing studies were done on chemically excysted metacercariae and on adults of Echinostoma revolutum maintained in vitro in agar-Locke's petri dish cultures at 39 +/- 1 C for up to 24 hr. Whereas newly excysted metacercariae did not pair, both immature and mature adults showed significant pairing. Adult echinostomes confined in dialysis sacs emitted excretory-secretory (EC) products which significantly attracted single echinostome adults in vitro. Only the lipophilic fraction of ES products was found to elicit attraction. Preparative TLC analysis of adult echinostomes produced three major bands as follows: I (phospholipids); II (free sterols); and III (free fatty acids + triglycerides). When tested in vitro, only the free sterol fraction significantly attracted single adult echinostomes. TLC and GLC analyses of free sterols of E. revolutum have indicated that cholesterol is the major free sterol. PMID:7218094

  15. Twinning and heteropaternity in chimpanzees (Pan troglodytes).

    PubMed

    Ely, John J; Frels, William I; Howell, Sue; Izard, M Kay; Keeling, Michale E; Lee, D Rick

    2006-05-01

    Unlike monozygotic (MZ) twins, dizygotic (DZ) twins develop from separate ova. The resulting twins can have different sires if the fertilizing sperm comes from different males. Routine paternity testing of a pair of same-sexed chimpanzee twins born to a female housed with two males indicated that the twins were sired by two different males. DNA typing of 22 short-tandem repeat (STR) loci demonstrated that these twins were not MZ twins but heteropaternal DZ twins. Reproductive data from 1926-2002 at five domestic chimpanzee colonies, including 52 twins and two triplets in 1,865 maternities, were used to estimate total twinning rates and the MZ and DZ components. The average chimpanzee MZ twinning rate (0.43%) equaled the average human MZ rate (0.48%). However, the chimpanzee DZ twinning rate (2.36%) was over twice the human average, and higher than all but the fertility-enhanced human populations of Nigeria. Similarly high twinning rates among African chimpanzees indicated that these estimates were not artifacts of captivity. Log-linear analyses of maternal and paternal effects on recurrent twinning indicated that females who twinned previously had recurrence risks five times greater than average, while evidence for a paternal twinning effect was weak. Chimpanzee twinning rates appear to be elevated relative to corresponding estimated human rates, making twinning and possibly heteropaternity more important features of chimpanzee reproductive biology than previously recognized. PMID:16353220

  16. Comparing Facial 3D Analysis With DNA Testing to Determine Zygosities of Twins.

    PubMed

    Vuollo, Ville; Sidlauskas, Mantas; Sidlauskas, Antanas; Harila, Virpi; Salomskiene, Loreta; Zhurov, Alexei; Holmström, Lasse; Pirttiniemi, Pertti; Heikkinen, Tuomo

    2015-06-01

    The aim of this study was to compare facial 3D analysis to DNA testing in twin zygosity determinations. Facial 3D images of 106 pairs of young adult Lithuanian twins were taken with a stereophotogrammetric device (3dMD, Atlanta, Georgia) and zygosity was determined according to similarity of facial form. Statistical pattern recognition methodology was used for classification. The results showed that in 75% to 90% of the cases, zygosity determinations were similar to DNA-based results. There were 81 different classification scenarios, including 3 groups, 3 features, 3 different scaling methods, and 3 threshold levels. It appeared that coincidence with 0.5 mm tolerance is the most suitable feature for classification. Also, leaving out scaling improves results in most cases. Scaling was expected to equalize the magnitude of differences and therefore lead to better recognition performance. Still, better classification features and a more effective scaling method or classification in different facial areas could further improve the results. In most of the cases, male pair zygosity recognition was at a higher level compared with females. Erroneously classified twin pairs appear to be obvious outliers in the sample. In particular, faces of young dizygotic (DZ) twins may be so similar that it is very hard to define a feature that would help classify the pair as DZ. Correspondingly, monozygotic (MZ) twins may have faces with quite different shapes. Such anomalous twin pairs are interesting exceptions, but they form a considerable portion in both zygosity groups.

  17. Heritability of regional and global brain structure at the onset of puberty: a magnetic resonance imaging study in 9-year-old twin pairs.

    PubMed

    Peper, Jiska S; Schnack, Hugo G; Brouwer, Rachel M; Van Baal, G Caroline M; Pjetri, Eneda; Székely, Eszter; van Leeuwen, Marieke; van den Berg, Stéphanie M; Collins, D Louis; Evans, Alan C; Boomsma, Dorret I; Kahn, René S; Hulshoff Pol, Hilleke E

    2009-07-01

    Puberty represents the phase of sexual maturity, signaling the change from childhood into adulthood. During childhood and adolescence, prominent changes take place in the brain. Recently, variation in frontal, temporal, and parietal areas was found to be under varying genetic control between 5 and 19 years of age. However, at the onset of puberty, the extent to which variation in brain structures is influenced by genetic factors (heritability) is not known. Moreover, whether a direct link between human pubertal development and brain structure exists has not been studied. Here, we studied the heritability of brain structures at 9 years of age in 107 monozygotic and dizygotic twin pairs (N = 210 individuals) using volumetric MRI and voxel-based morphometry. Children showing the first signs of secondary sexual characteristics (N = 47 individuals) were compared with children without these signs, based on Tanner-stages. High heritabilities of intracranial, total brain, cerebellum, and gray and white matter volumes (up to 91%) were found. Regionally, the posterior fronto-occipital, corpus callosum, and superior longitudinal fascicles (up to 93%), and the amygdala, superior frontal and middle temporal cortices (up to 83%) were significantly heritable. The onset of secondary sexual characteristics of puberty was associated with decreased frontal and parietal gray matter densities. Thus, in 9-year-old children, global brain volumes, white matter density in fronto-occipital and superior longitudinal fascicles, and gray matter density of (pre-)frontal and temporal areas are highly heritable. Pubertal development may be directly involved in the decreases in gray matter areas that accompany the transition of our brains from childhood into adulthood.

  18. Twins Early Development Study (TEDS): A Genetically Sensitive Investigation of Cognitive and Behavioral Development From Childhood to Young Adulthood

    PubMed Central

    Haworth, Claire M. A.; Davis, Oliver S. P.; Plomin, Robert

    2013-01-01

    The Twins Early Development Study (TEDS) is a large longitudinal sample of twins born in England and Wales between 1994 and 1996. The focus of TEDS has been on cognitive and behavioral development, including difficulties in the context of normal development. TEDS began when multiple births were identified from birth records and the families were invited to take part in the study; 16,810 pairs of twins were originally enrolled in TEDS. More than 10,000 of these twin pairs remain enrolled in the study to date. DNA has been collected for more than 7,000 pairs, and genome-wide genotyping data for two million DNA markers are available for 3,500 individuals. The TEDS families have taken part in studies when the twins were aged 2, 3, 4, 7, 8, 9, 10, 12, 14, and 16 years of age. Data collection is currently underway to assess the adult destinations of the twins as they move from school to university and the workplace. Between January 2012 and December 2014, all of the TEDS twins will turn 18, and the study will transition to an adult sample. TEDS represents an outstanding resource for investigating the developmental effects of genes and environments on complex quantitative traits from childhood to young adulthood and beyond. PMID:23110994

  19. Congenital toxoplasmosis in premature twins.

    PubMed

    Sibalić, D; Djurković-Djaković, O; Nikolić, R

    1986-01-01

    In the course of the study "Toxoplasmosis and Prematurity" 330 blood samples from twins were examined. Our findings in a series of 21 premature twins (maternal sera were also examined) are reported in this paper. Toxoplasma antibodies were detected by the Sabin-Feldman test and specific IgM antibodies by the Remington test. The classical form of congenital toxoplasmosis was present in five pairs of twins, while toxoplasmosis was subclinical at birth in both twins of three pairs. The pattern of disease varied very much in seven pairs of twins. In one twin of two pairs signs of disease were present, while his cotwin appeared unaffected but with strongly positive result of SFT. The most interesting observation, however, is that in three pairs, one twin was infected and had evident congenital toxoplasmosis, while his cotwin was not, as proven by the disappearance of the Toxoplasma antibodies. This finding undoubtedly indicates the importance of whether the placenta is intact or not for the transmission of the infection.

  20. Is "g" an Entity? A Japanese Twin Study Using Syllogisms and Intelligence Tests

    ERIC Educational Resources Information Center

    Shikishima, Chizuru; Hiraishi, Kai; Yamagata, Shinji; Sugimoto, Yutaro; Takemura, Ryo; Ozaki, Koken; Okada, Mitsuhiro; Toda, Tatsushi; Ando, Juko

    2009-01-01

    Using a behavioral genetic approach, we examined the validity of the hypothesis concerning the singularity of human general intelligence, the "g" theory, by analyzing data from two tests: the first consisted of 100 syllogism problems and the second a full-scale intelligence test. The participants were 448 Japanese young adult twins (167 pairs of…

  1. Genetic Influences on Perceptions of Childhood Family Environment: A Reared Apart Twin Study.

    ERIC Educational Resources Information Center

    Hur, Yoon-Mi; Bouchard, Thomas J., Jr.

    1995-01-01

    Estimates the extent to which heredity influences perceptions of childhood family environment in a sample of 58 monozygotic and 46 dizygotic pairs of adult twins who were reared apart. The data confirm the importance of genetic factors in some, but not all, measures of family environment. Environmental influences were more important than genetic…

  2. Dogs Discriminate Identical Twins

    PubMed Central

    Pinc, Ludvík; Bartoš, Luděk; Reslová, Alice; Kotrba, Radim

    2011-01-01

    Earlier studies have shown variation among experimental attempts to establish whether human monozygotic twins that are genetically identical also have identical individual scents. In none of the cases were the dogs able to distinguish all the individual scents of monozygotic twins living in the same environment if the scents were presented to them separately. Ten specially trained police German Shepherd dogs of three Czech Republic Police Regional Headquarters were used for scent identification in our study. The dogs were supposed to match scents of two monozygotic pairs (5 and 7 years old) and two dizygotic twin pairs (8 and 13 years old). Scents were collected on cotton squares stored in glass jars. Dog handlers were blind to the experiment details. In each trial (line-up), one scent was used as a starting scent and the dog was then sent to determine if any of the 7 presented glass jars contained a matching scent. Scents of children of similar ages were used as distractors. In the matching procedure, the dogs matched correctly the scent of one twin with the other, as well as two scents collected from every single identical and non-identical twin to prove their efficacy and likewise, the presence of the matching twin scent in any given glass jar. All dogs in all trials distinguished correctly the scents of identical as well as non-identical twins. All dogs similarly matched positively two scents collected from the same individuals. Our findings indicated that specially trained German Shepherd dogs are able to distinguish individual scents of identical twins despite the fact that they live in the same environment, eat the same food and even if the scents are not presented to them simultaneously. PMID:21698282

  3. Dogs discriminate identical twins.

    PubMed

    Pinc, Ludvík; Bartoš, Luděk; Reslová, Alice; Kotrba, Radim

    2011-01-01

    Earlier studies have shown variation among experimental attempts to establish whether human monozygotic twins that are genetically identical also have identical individual scents. In none of the cases were the dogs able to distinguish all the individual scents of monozygotic twins living in the same environment if the scents were presented to them separately. Ten specially trained police German Shepherd dogs of three Czech Republic Police Regional Headquarters were used for scent identification in our study. The dogs were supposed to match scents of two monozygotic pairs (5 and 7 years old) and two dizygotic twin pairs (8 and 13 years old). Scents were collected on cotton squares stored in glass jars. Dog handlers were blind to the experiment details. In each trial (line-up), one scent was used as a starting scent and the dog was then sent to determine if any of the 7 presented glass jars contained a matching scent. Scents of children of similar ages were used as distractors. In the matching procedure, the dogs matched correctly the scent of one twin with the other, as well as two scents collected from every single identical and non-identical twin to prove their efficacy and likewise, the presence of the matching twin scent in any given glass jar. All dogs in all trials distinguished correctly the scents of identical as well as non-identical twins. All dogs similarly matched positively two scents collected from the same individuals. Our findings indicated that specially trained German Shepherd dogs are able to distinguish individual scents of identical twins despite the fact that they live in the same environment, eat the same food and even if the scents are not presented to them simultaneously. PMID:21698282

  4. Physically active vs. inactive lifestyle, muscle properties, and glucose homeostasis in middle-aged and older twins.

    PubMed

    Leskinen, T; Sipilä, S; Kaprio, J; Kainulainen, H; Alen, M; Kujala, U M

    2013-10-01

    Exercise-induced positive changes in skeletal muscle properties and metabolism decrease the risk for disability, cardiometabolic diseases and mortality. Here, we studied muscle properties and glucose homeostasis in a non-exercise stage in twin pairs with co-twins discordant for physical activity habits for at least 32 years of their adult lives. Isometric knee extension force, MR imaging of midthigh tissue composition and muscle volume, and fasting blood samples were acquired from 16 same-sex (seven monozygotic, nine dizygotic) middle-aged and older twin pairs. The consistently active twins had 20 % higher knee extension forces than their inactive co-twins (p = 0.006) although the active twins had only 4 % higher midthigh muscle cross-sectional areas (p = 0.072). These results were similar in intrapair analysis in which only the seven identical twin pairs were included. The ratio between the area of midthigh fat and muscle tissues was significantly lower among the active twins (0.65 vs. 0.48, p = 0.006). The active twins had also lower fasting plasma glucose levels (5.1 vs 5.6 mmol/l, p = 0.041). The area of midthigh intramuscular (extramyocellular) fat was associated with the markers of glucose homeostasis, especially with glycated hemoglobin, and these associations were emphasized by the diabetic and inactive twins. Regular exercise throughout the adult life retains muscle strength and quality but not necessarily mass. The regular use of muscles also prevents from the accumulation of intramuscular fat which might be related to maintained glucose metabolism and, thus, prevention of metabolic disorders. PMID:23124702

  5. Genetic and Environmental Influences on Traits of Gender Identity Disorder: A Study of Japanese Twins Across Developmental Stages.

    PubMed

    Sasaki, Shoko; Ozaki, Koken; Yamagata, Shinji; Takahashi, Yusuke; Shikishima, Chizuru; Kornacki, Tamara; Nonaka, Koichi; Ando, Juko

    2016-10-01

    The present study examined: (1) gender and age differences of mean gender identity disorder (GID) trait scores in Japanese twins; (2) the validity of the prenatal hormone transfer theory, which predicts that, in dizygotic (DZ) twin pairs, twins with an opposite-gender co-twin more frequently exhibit GID traits than twins with a same-gender co-twin; and (3) the magnitude of genetic and environmental influences on GID traits as a function of age and gender. Data from 1450 male twin pairs, 1882 female twin pairs, and 1022 DZ male-female pairs ranging from 3 to 26 years of age were analyzed. To quantify individual variances in GID traits, each participant completed four questionnaire items based on criteria for GID from the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Our most important findings were: (1) Japanese females exhibited GID traits more frequently than males and Japanese children exhibited GID traits less frequently than adolescents and adults (among females, the prevalence was 1.6 % in children, 10 % in adolescents, and 12 % in adults; among males, the prevalence was 0.5, 2, and 3 %, respectively); (2) the data did not support the prenatal hormone transfer theory for GID traits; and (3) a large part of the variance for GID traits in children was accounted for by familial factors; however, the magnitude was found to be greater in children than in adolescents or adults, particularly among females. This study suggests that although the prevalence is likely to increase, familial effects are likely to decrease as individuals age. PMID:27507021

  6. Genetic and Environmental Influences on Traits of Gender Identity Disorder: A Study of Japanese Twins Across Developmental Stages.

    PubMed

    Sasaki, Shoko; Ozaki, Koken; Yamagata, Shinji; Takahashi, Yusuke; Shikishima, Chizuru; Kornacki, Tamara; Nonaka, Koichi; Ando, Juko

    2016-10-01

    The present study examined: (1) gender and age differences of mean gender identity disorder (GID) trait scores in Japanese twins; (2) the validity of the prenatal hormone transfer theory, which predicts that, in dizygotic (DZ) twin pairs, twins with an opposite-gender co-twin more frequently exhibit GID traits than twins with a same-gender co-twin; and (3) the magnitude of genetic and environmental influences on GID traits as a function of age and gender. Data from 1450 male twin pairs, 1882 female twin pairs, and 1022 DZ male-female pairs ranging from 3 to 26 years of age were analyzed. To quantify individual variances in GID traits, each participant completed four questionnaire items based on criteria for GID from the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Our most important findings were: (1) Japanese females exhibited GID traits more frequently than males and Japanese children exhibited GID traits less frequently than adolescents and adults (among females, the prevalence was 1.6 % in children, 10 % in adolescents, and 12 % in adults; among males, the prevalence was 0.5, 2, and 3 %, respectively); (2) the data did not support the prenatal hormone transfer theory for GID traits; and (3) a large part of the variance for GID traits in children was accounted for by familial factors; however, the magnitude was found to be greater in children than in adolescents or adults, particularly among females. This study suggests that although the prevalence is likely to increase, familial effects are likely to decrease as individuals age.

  7. The Nature and Nurture of Melody: A Twin Study of Musical Pitch and Rhythm Perception.

    PubMed

    Seesjärvi, Erik; Särkämö, Teppo; Vuoksimaa, Eero; Tervaniemi, Mari; Peretz, Isabelle; Kaprio, Jaakko

    2016-07-01

    Both genetic and environmental factors are known to play a role in our ability to perceive music, but the degree to which they influence different aspects of music cognition is still unclear. We investigated the relative contribution of genetic and environmental effects on melody perception in 384 young adult twins [69 full monozygotic (MZ) twin pairs, 44 full dizygotic (DZ) twin pairs, 70 MZ twins without a co-twin, and 88 DZ twins without a co-twin]. The participants performed three online music tests requiring the detection of pitch changes in a two-melody comparison task (Scale) and key and rhythm incongruities in single-melody perception tasks (Out-of-key, Off-beat). The results showed predominantly additive genetic effects in the Scale task (58 %, 95 % CI 42-70 %), shared environmental effects in the Out-of-key task (61 %, 49-70 %), and non-shared environmental effects in the Off-beat task (82 %, 61-100 %). This highly different pattern of effects suggests that the contribution of genetic and environmental factors on music perception depends on the degree to which it calls for acquired knowledge of musical tonal and metric structures. PMID:26650514

  8. The Nature and Nurture of Melody: A Twin Study of Musical Pitch and Rhythm Perception.

    PubMed

    Seesjärvi, Erik; Särkämö, Teppo; Vuoksimaa, Eero; Tervaniemi, Mari; Peretz, Isabelle; Kaprio, Jaakko

    2016-07-01

    Both genetic and environmental factors are known to play a role in our ability to perceive music, but the degree to which they influence different aspects of music cognition is still unclear. We investigated the relative contribution of genetic and environmental effects on melody perception in 384 young adult twins [69 full monozygotic (MZ) twin pairs, 44 full dizygotic (DZ) twin pairs, 70 MZ twins without a co-twin, and 88 DZ twins without a co-twin]. The participants performed three online music tests requiring the detection of pitch changes in a two-melody comparison task (Scale) and key and rhythm incongruities in single-melody perception tasks (Out-of-key, Off-beat). The results showed predominantly additive genetic effects in the Scale task (58 %, 95 % CI 42-70 %), shared environmental effects in the Out-of-key task (61 %, 49-70 %), and non-shared environmental effects in the Off-beat task (82 %, 61-100 %). This highly different pattern of effects suggests that the contribution of genetic and environmental factors on music perception depends on the degree to which it calls for acquired knowledge of musical tonal and metric structures.

  9. Access to green space, physical activity and mental health: a twin study

    PubMed Central

    Cohen-Cline, Hannah; Turkheimer, Eric; Duncan, Glen E

    2015-01-01

    Background Increasing global urbanisation has resulted in a greater proportion of the world’s population becoming exposed to risk factors unique to urban areas, and understanding these effects on public health is essential. The aim of this study was to examine the association between access to green space and mental health among adult twin pairs. Methods We used a multilevel random intercept model of same-sex twin pairs (4338 individuals) from the community-based University of Washington Twin Registry to analyse the association between access to green space, as measured by the Normalised Difference Vegetation Index and self-reported depression, stress, and anxiety. The main parameter of interest was the within-pair effect for identical (monozygotic, MZ) twins because it was not subject to confounding by genetic or shared childhood environment factors. Models were adjusted for income, physical activity, neighbourhood deprivation and population density. Results When treating twins as individuals and not as members of a twin pair, green space was significantly inversely associated with each mental health outcome. The association with depression remained significant in the within-pair MZ univariate and adjusted models; however, there was no within-pair MZ effect for stress or anxiety among the models adjusted for income and physical activity. Conclusions These results suggest that greater access to green space is associated with less depression, but provide less evidence for effects on stress or anxiety. Understanding the mechanisms linking neighbourhood characteristics to mental health has important public health implications. Future studies should combine twin designs and longitudinal data to strengthen causal inference. PMID:25631858

  10. X-inactivation patterns in monozygotic and dizygotic female twins

    SciTech Connect

    Goodship, J.; Carter, J.; Burn, J.

    1996-01-22

    We have tested the hypothesis that contrasting X-inactivation patterns could be a trigger for monozygotic twinning in females. X-inactivation patterns were studied in umbilical cord tissue in 43 monozygotic twin pairs and 24 dizygotic twin pairs. Very skewed or non-random X-inactivation patterns were observed in both twins in six of the monozygotic twin pairs and in one of the dizygotic twin pairs. Contrasting X-inactivation patterns occurred in only one of the six monozygotic twin pairs. This does not support the original hypothesis. There is a trend to extreme skewing of X-inactivation pattern occurring more frequently in monozygotic twins. 21 refs., 1 fig., 2 tabs.

  11. Lipoprotein(a) in women twins: Heritability and relationship to apolipoprotein(a) phenotypes

    SciTech Connect

    Austin, M.A. ); Sandholzer, C.; Utermann, G. ); Selby, J.V. ); Newman, B. ); Krauss, R.M. )

    1992-10-01

    Lp(a) is a unique lipoprotein consisting of an LDL-like particle and a characteristic protein, apo(a). Increased levels of Lp(a) constitute a risk factor for coronary heart disease. Variation in the size of the apo(a) protein is a phenotype controlled by the apo(a) gene on chromosome 6 and is related to Lp(a) plasma levels. Based on 169 MZ and 125 DZ adult female twin pairs, this study's purpose was to estimate the proportion of the variation in Lp(a) levels that is due to genetic influences and to determine the extent to which the apo(a) locus explains this heritability. Lp(a) levels were significantly more similar in MZ twins than in DZ twins: mean co-twin differences were 3.9 [+-] 5.7 mg/dl and 16.0 [+-] 19.9 mg/dl (P < .001), respectively. Intraclass correlations were .94 in MZ twins and .32 in DZ twins, resulting in a heritability estimate of .94 (P < .001). Heritability was then calculated using only co-twins with the same apo(a) phenotype: the heritability estimate decreased to .45 but was still highly significant (P < .001). Therefore, on the basis of heritability analysis of women twins, Lp(a) levels are almost entirely genetically controlled. Variation at the apo(a) locus contributes to this heritability, although other genetic factors could be involved. 66 refs., 2 figs., 4 tabs.

  12. A Multivariate Twin Study of Early Literacy in Japanese "Kana"

    ERIC Educational Resources Information Center

    Fujisawa, Keiko K.; Wadsworth, Sally J.; Kakihana, Shinichiro; Olson, Richard K.; DeFries, John C.; Byrne, Brian; Ando, Juko

    2013-01-01

    This first Japanese twin study of early literacy development investigated the extent to which genetic and environmental factors influence individual differences in prereading skills in 238 pairs of twins at 42 months of age. Twin pairs were individually tested on measures of phonological awareness, "kana" letter name/sound knowledge, receptive…

  13. Twins with schizophrenia: genes or germs?

    PubMed

    Davis, J O; Phelps, J A

    1995-01-01

    High concordance for schizophrenia in monozygotic (MZ) twins is often cited as evidence for the etiological influence of genetics; however, even if twins are separated at birth, MZ twin concordance is influenced by the shared prenatal environment. Study of the placentation status of MZ twins provides a way to investigate some prenatal influences, including the possible role of viral infections. The probability of shared infections is likely to be greater in monochorionic MZ twin pairs than in dichorionic pairs because of shared fetal circulation in the monochorionic pairs. We drew from published twin studies and used reported concordance for handedness as a retrospective marker of placentation status. We found that MZ twin pairs with opposite-hand preferences were concordant for psychosis in 9 of 15 cases (60%), while only 18 of 56 twin pairs (32%) with same-hand preferences were concordant for psychosis. These results suggest that shared prenatal viral infection may account for much of the high concordance for schizophrenia in identical twins. PMID:7770735

  14. Beyond Heritability: Twin Studies in Behavioral Research

    PubMed Central

    Johnson, Wendy; Turkheimer, Eric; Gottesman, Irving I.; Bouchard, Thomas J.

    2010-01-01

    The heritability of human behavioral traits is now well established, due in large measure to classical twin studies. We see little need for further studies of the heritability of individual traits in behavioral science, but the twin study is far from having outlived its usefulness. The existence of pervasive familial influences on behavior means that selection bias is always a concern in any study of the causal effects of environmental circumstances. Twin samples continue to provide new opportunities to identify causal effects with appropriate genetic and shared environmental controls. We discuss environmental studies of discordant twin pairs and twin studies of genetic and environmental transactions in this context. PMID:20625474

  15. Analysis of clinical efficacy of interceptive treatment of Class II division 2 malocclusion in a pair of twins through the use of two modified removable appliances

    PubMed Central

    CONDÒ, R.; PERUGIA, C.; BARTOLINO, M.; DOCIMO, R.

    2011-01-01

    SUMMARY The interceptive therapeutic approach of a functional type is indicated for the treatment of Class II Division 2 mandibular retrusion with deep bite, where improvement is required not only in occlusal relationships but also in skeletal and aesthetic parameters. Purpose The aim of this study is to assess, in two identical twins suffering from the same malocclusion, the effectiveness and clinical stability of functional interceptive Class II division 2 treatment during puberty by mandibular retro-positioning associated with deep bite, and to compare skeletal changes and dental and dental-alveolar changes induced by the application of two different modified removable appliances: Clark’s Twin block and Bergersen’s Occlus-o-guide. Results The results show that both devices allowed for circumvention of the pre-functional therapy phase aimed at correcting the upper labial segment, and for the conversion of the Class II division 1 incisor relationship, they were able to promote significant and obvious clinical effects. Conclusions The study shows that Class II Division 2 functional type interceptive treatment of mandibular retrusion with deep bite conducted in the puberal phase through clinical use of modified Bergersen’s Occlus-o-guide® allowed for simultaneous resolution of the skeletal, dental-alveolar and dental problems in one step, while that using modified Clark’s Twin-block still requires a second phase of treatment necessary to resolve the alignment, levelling, inter-cuspidation of the arches, optimization of the dental overjet and overbite parameters and to the stabilization of the basal Class I. PMID:23285386

  16. Twin-to-Twin Transfusion Syndrome

    PubMed Central

    Mahieu-Caputo, Dominique; Dommergues, Marc; Delezoide, Anne-Lise; Lacoste, Mireille; Cai, Yi; Narcy, Françoise; Jolly, Dominique; Gonzales, Marie; Dumez, Yves; Gubler, Marie-Claire

    2000-01-01

    The twin-to-twin transfusion syndrome (TTS) results from an unbalanced blood supply through placental anastomoses in monochorionic twins. It induces growth restriction, renal tubular dysgenesis, and oliguria in the donor and visceromegaly and polyuria in the recipient. A better understanding of its pathophysiology could contribute to improving the management of TTS, which still carries a high perinatal mortality in both twins. As well as several other candidates, the renin-angiotensin system might be involved in TTS. To evaluate its role in the pathogenesis of the syndrome, we studied the kidneys of 21 twin pairs who died from TTS at 19 to 30 weeks, compared with 39 individuals in a control group, using light microscopy, immunohistochemistry, and in situ hybridization. The overexpression of the renin protein and transcript with frequent evidence of renin synthesis by mesangial cells was observed in the donor kidneys, presumably as a consequence of chronic renal hypoperfusion. This upregulation of renin synthesis might be beneficial to restore euvolemia. In severe cases of TTS, however, angiotensin-II-induced vasoconstriction acts as an additional deleterious factor by further reducing the renal blood flow in donors. In recipients, renin expression was virtually absent, possibly because it was down-regulated by hypervolemia. However, in addition to congestion and hemorrhagic infarction, there were severe glomerular and arterial lesions resembling those observed in polycythemia- or hypertension-induced microangiopathy. We speculate that fetal hypertension in the recipient might be partly mediated by the transfer of circulating renin produced by the donor, through the placental vascular shunts. PMID:10666392

  17. Methylomic analysis of monozygotic twins discordant for childhood psychotic symptoms

    PubMed Central

    Fisher, Helen L; Murphy, Therese M; Arseneault, Louise; Caspi, Avshalom; Moffitt, Terrie E; Viana, Joana; Hannon, Eilis; Pidsley, Ruth; Burrage, Joe; Dempster, Emma L; Wong, Chloe C Y; Pariante, Carmine M; Mill, Jonathan

    2015-01-01

    Childhood psychotic symptoms are associated with increased rates of schizophrenia, other psychiatric disorders, and suicide attempts in adulthood; thus, elucidating early risk indicators is crucial to target prevention efforts. There is considerable discordance for psychotic symptoms between monozygotic twins, indicating that child-specific non-genetic factors must be involved. Epigenetic processes may constitute one of these factors and have not yet been investigated in relation to childhood psychotic symptoms. Therefore, this study explored whether differences in DNA methylation at age 10 were associated with monozygotic twin discordance for psychotic symptoms at age 12. The Environmental Risk (E-Risk) Longitudinal Twin Study cohort of 2,232 children (1,116 twin pairs) was assessed for age-12 psychotic symptoms and 24 monozygotic twin pairs discordant for symptoms were identified for methylomic comparison. Children provided buccal samples at ages 5 and 10. DNA was bisulfite modified and DNA methylation was quantified using the Infinium HumanMethylation450 array. Differentially methylated positions (DMPs) associated with psychotic symptoms were subsequently tested in post-mortem prefrontal cortex tissue from adult schizophrenia patients and age-matched controls. Site-specific DNA methylation differences were observed at age 10 between monozygotic twins discordant for age-12 psychotic symptoms. Similar DMPs were not found at age 5. The top-ranked psychosis-associated DMP (cg23933044), located in the promoter of the C5ORF42 gene, was also hypomethylated in post-mortem prefrontal cortex brain tissue from schizophrenia patients compared to unaffected controls. These data tentatively suggest that epigenetic variation in peripheral tissue is associated with childhood psychotic symptoms and may indicate susceptibility to schizophrenia and other mental health problems. PMID:26479702

  18. Double effort: Parental behavior of wild Azara's owl monkeys in the face of twins.

    PubMed

    Huck, Maren; Van Lunenburg, Mari; Dávalos, Victor; Rotundo, Marcelo; Di Fiore, Anthony; Fernandez-Duque, Eduardo

    2014-07-01

    In species of mammals that habitually bear single offspring, like most anthropoid primates, the occurrence of twins is expected to impose considerable energetic costs on the caretakers. The question then arises of how caregivers cope with the potentially increased costs of raising twins. These increased costs should lead to differing developmental rates in twins when compared to singletons, and/or to changes in the caregivers' behavior. Likewise, time budgets of parents of singletons are expected to differ from those of adults without offspring. Additionally, if twinning was an adaptive response to favorable ecological conditions, it should be more likely in years with high food abundance. Following the birth in 2011 of two sets of twins in a wild population of pair-living Azara's owl monkeys (Aotus azarae) in Northern Argentina, we used long-term demographic, behavioral, and phenological data to compare (a) the proportion of time that singleton and twin infants were carried by either parent; (b) adult time budgets and ranging behavior in groups with zero, one, or two infants; and (c) the availability of food in 2011 with food availability in other years. Twins, like singletons, were carried nearly exclusively by the male, and they were carried slightly more than singletons, suggesting a relatively inflexible pattern of infant care in the species. Time budgets showed that twin parents foraged more and moved less than singleton parents or groups without infants, despite the fact that phenological data indicate that fruit availability in 2011 was not substantially higher than in some of the other years. Overall, twinning thus presumably increased costs to breeders, especially males, but its effect on animals' long-term reproductive success remains unclear.

  19. Sexual Behavior in Young Adulthood: A Population-Based Twin Study

    PubMed Central

    Mustanski, Brian; Viken, Richard J.; Kaprio, Jaakko; Winter, Torsten; Rose, Richard J.

    2007-01-01

    Objective With behavior genetic analyses of data from young adult twins, we evaluated theoretical perspectives that differentially emphasize biological dispositions, social/cultural factors, or universal pathways to explain individual differences in sexual behaviors. Design We fit biometric sex limitation models to three aspects of sexual behavior reported by 4,925 Finnish twins aged 23–27. The sample, from five consecutive birth cohorts, of 2,448 twin pairs (886 sister-sister, 862 brother-sister, 700 brother-brother), included 785 monozygotic and 801 same-sex dizygotic pairs. In addition to model fitting data from twin pairs, we conducted analyses on twins as individuals to test for independence of initiation of sexual behavior from onset age and number of partners. Main Outcome Measures From a postal questionnaire, we obtained self-report information on initiation/abstinence of sexual intercourse, onset age, and number of sexual partners. Results Genetic and non-shared environmental influences were significant for all three measures. There were trends for common environmental influences on initiation and, in females, age at first intercourse. Some differential effects in males and females were found. Results comparing onset age and number of partners among experienced twins from pairs concordant and discordant for initiation found genetic and environmental influences on initiation/abstinence overlapped those found for the other aspects of sexual behavior. Conclusions These results document genetic variation in individual differences in sexual behavior of young adults. Incorporating genetic dispositions into integrated models of sexual behavior will facilitate more effective health promotion and risk taking intervention. PMID:17845112

  20. Tests of a Direct Effect of Childhood Abuse on Adult Borderline Personality Disorder Traits: A Longitudinal Discordant Twin Design

    PubMed Central

    Bornovalova, Marina A.; Huibregtse, Brooke M.; Hicks, Brian M.; Keyes, Margaret; McGue, Matt; Iacono, William

    2012-01-01

    We used a longitudinal twin design to examine the causal association between sexual, emotional, and physical abuse in childhood (before age 18) and borderline personality disorder (BPD) traits at age 24 using a discordant twin design and biometric modeling. Additionally, we examined the mediating and moderating effects of symptoms of childhood externalizing and internalizing disorders on the link between childhood abuse and BPD traits. Although childhood abuse, BPD traits, and internalizing and externalizing symptoms were all correlated, the discordant twin analyses and biometric modeling showed little to no evidence that consistent with a causal effect of childhood abuse on BPD traits. Instead, our results indicate that the association between childhood abuse and BPD traits stems from common genetic influences that, in some cases, also overlap with internalizing and externalizing disorders. These findings are inconsistent with the widely held assumption that childhood abuse causes BPD, and suggests that BPD traits in adulthood are better accounted for by heritable vulnerabilities to internalizing and externalizing disorders. PMID:22686871

  1. Genetic and environmental contributions to long-term sick leave and disability pension: a population-based study of young adult Norwegian twins.

    PubMed

    Gjerde, Line C; Knudsen, Gun Peggy; Czajkowski, Nikolai; Gillespie, Nathan; Aggen, Steven H; Røysamb, Espen; Reichborn-Kjennerud, Ted; Tambs, Kristian; Kendler, Kenneth S; Orstavik, Ragnhild E

    2013-08-01

    Although exclusion from the workforce due to long-term sick leave (LTSL) and disability pension (DP) is a major problem in many Western countries, the etiology of LTSL and DP is not well understood. These phenomena have a strong association as most patients receiving DP have first been on LTSL. However, only a few of those on LTSL end up with DP. The present study aimed to investigate the common and specific genetic and environmental risk factors for LTSL and DP. The present study utilizes a population-based sample of 7,710 young adult twins from the Norwegian Institute of Public Health Twin Panel, which has been linked to the Historical-Event Database (FD-Trygd; 1998-2008). Univariate and bivariate twin models were fitted to determine to what degree genetic and environmental factors contribute to variation in LTSL and DP. The estimated heritabilities of LTSL and DP were 0.49 and 0.66, respectively. There was no evidence for shared environmental or sex-specific factors. The phenotypic-, genetic-, and non-familial environmental correlations between the variables were 0.86, 0.82, and 0.94, respectively. Our results indicate that familial transmission of LTSL and DP is due to genetic and not environmental factors. The risk factors contributing to LTSL and DP were mainly shared, suggesting that what increases risk for LTSL also increases risk for DP. However, a non-negligible part of the genetic variance was not shared between the variables, which may contribute to explaining why some progress from LTSL to DP, whereas others return to work.

  2. The Charles Perkins Centre's Twins Research Node.

    PubMed

    Ferreira, Lucas C; Craig, Jeffrey M; Hopper, John L; Carrick, Susan E

    2016-08-01

    Twins can help researchers disentangle the roles of genes from those of the environment on human traits, health, and diseases. To realize this potential, the Australian Twin Registry (ATR), University of Melbourne, and the Charles Perkins Centre (CPC), University of Sydney, established a collaboration to form the Twins Research Node, a highly interconnected research facility dedicated specifically to research involving twins. This collaboration aims to foster the adoption of twin designs as important tools for research in a range of health-related domains. The CPC hosted their Twins Research Node's launch seminar entitled 'Double the power of your research with twin studies', in which experienced twin researchers described how twin studies are supporting scientific discoveries and careers. The launch also featured twin pairs who have actively participated in research through the ATR. Researchers at the CPC were surveyed before the event to gauge their level of understanding and interest in utilizing twin research. This article describes the new Twins Research Node, discusses the survey's main results and reports on the launch seminar. PMID:27302367

  3. Early Life Manipulations of the Nonapeptide System Alter Pair Maintenance Behaviors and Neural Activity in Adult Male Zebra Finches

    PubMed Central

    Baran, Nicole M.; Tomaszycki, Michelle L.; Adkins-Regan, Elizabeth

    2016-01-01

    Adult zebra finches (T. guttata) form socially monogamous pair bonds characterized by proximity, vocal communication, and contact behaviors. In this experiment, we tested whether manipulations of the nonapeptide hormone arginine vasotocin (AVT, avian homolog of vasopressin) and the V1a receptor (V1aR) early in life altered species-typical pairing behavior in adult zebra finches of both sexes. Although there was no effect of treatment on the tendency to pair in either sex, males in different treatments exhibited profoundly different profiles of pair maintenance behavior. Following a brief separation, AVT-treated males were highly affiliative with their female partner but sang very little compared to Controls. In contrast, males treated with a V1aR antagonist sang significantly less than Controls, but did not differ in affiliation. These effects on behavior in males were also reflected in changes in the expression of V1aR and immediate early gene activity in three brain regions known to be involved in pairing behavior in birds: the medial amygdala, medial bed nucleus of the stria terminalis, and the lateral septum. AVT males had higher V1aR expression in the medial amygdala than both Control and antagonist-treated males and immediate early gene activity of V1aR neurons in the medial amygdala was positively correlated with affiliation. Antagonist treated males showed decreased activity in the medial amygdala. In addition, there was a negative correlation between the activity of V1aR cells in the medial bed nucleus of the stria terminalis and singing. Treatment also affected the expression of V1aR and activity in the lateral septum, but this was not correlated with any behaviors measured. These results provide evidence that AVT and V1aR play developmental roles in specific pair maintenance behaviors and the neural substrate underlying these behaviors in a bird. PMID:27065824

  4. Early Life Manipulations of the Nonapeptide System Alter Pair Maintenance Behaviors and Neural Activity in Adult Male Zebra Finches.

    PubMed

    Baran, Nicole M; Tomaszycki, Michelle L; Adkins-Regan, Elizabeth

    2016-01-01

    Adult zebra finches (T. guttata) form socially monogamous pair bonds characterized by proximity, vocal communication, and contact behaviors. In this experiment, we tested whether manipulations of the nonapeptide hormone arginine vasotocin (AVT, avian homolog of vasopressin) and the V1a receptor (V1aR) early in life altered species-typical pairing behavior in adult zebra finches of both sexes. Although there was no effect of treatment on the tendency to pair in either sex, males in different treatments exhibited profoundly different profiles of pair maintenance behavior. Following a brief separation, AVT-treated males were highly affiliative with their female partner but sang very little compared to Controls. In contrast, males treated with a V1aR antagonist sang significantly less than Controls, but did not differ in affiliation. These effects on behavior in males were also reflected in changes in the expression of V1aR and immediate early gene activity in three brain regions known to be involved in pairing behavior in birds: the medial amygdala, medial bed nucleus of the stria terminalis, and the lateral septum. AVT males had higher V1aR expression in the medial amygdala than both Control and antagonist-treated males and immediate early gene activity of V1aR neurons in the medial amygdala was positively correlated with affiliation. Antagonist treated males showed decreased activity in the medial amygdala. In addition, there was a negative correlation between the activity of V1aR cells in the medial bed nucleus of the stria terminalis and singing. Treatment also affected the expression of V1aR and activity in the lateral septum, but this was not correlated with any behaviors measured. These results provide evidence that AVT and V1aR play developmental roles in specific pair maintenance behaviors and the neural substrate underlying these behaviors in a bird. PMID:27065824

  5. Asynchronous Vowel-Pair Identification across the Adult Life Span for Monaural and Dichotic Presentations

    ERIC Educational Resources Information Center

    Fogerty, Daniel; Kewley-Port, Diane; Humes, Larry E.

    2012-01-01

    Purpose: Temporal order abilities decrease with age. Declining temporal processing abilities may influence the identification of rapid vowel sequences. Identification patterns for asynchronous vowel pairs were explored across the life span. Method: Young, middle-aged, and older listeners completed temporal order tasks for pairs of 70-ms and 40-ms…

  6. Is that me or my twin? Lack of self-face recognition advantage in identical twins.

    PubMed

    Martini, Matteo; Bufalari, Ilaria; Stazi, Maria Antonietta; Aglioti, Salvatore Maria

    2015-01-01

    Despite the increasing interest in twin studies and the stunning amount of research on face recognition, the ability of adult identical twins to discriminate their own faces from those of their co-twins has been scarcely investigated. One's own face is the most distinctive feature of the bodily self, and people typically show a clear advantage in recognizing their own face even more than other very familiar identities. Given the very high level of resemblance of their faces, monozygotic twins represent a unique model for exploring self-face processing. Herein we examined the ability of monozygotic twins to distinguish their own face from the face of their co-twin and of a highly familiar individual. Results show that twins equally recognize their own face and their twin's face. This lack of self-face advantage was negatively predicted by how much they felt physically similar to their co-twin and by their anxious or avoidant attachment style. We speculate that in monozygotic twins, the visual representation of the self-face overlaps with that of the co-twin. Thus, to distinguish the self from the co-twin, monozygotic twins have to rely much more than control participants on the multisensory integration processes upon which the sense of bodily self is based. Moreover, in keeping with the notion that attachment style influences perception of self and significant others, we propose that the observed self/co-twin confusion may depend upon insecure attachment. PMID:25853249

  7. Infant twins' social interactions with caregivers and same-age siblings.

    PubMed

    Aldrich, Naomi J; Brooks, Patricia J; Yuksel-Sokmen, P Ozlem; Ragir, Sonia; Flory, Michael J; Lennon, Elizabeth M; Karmel, Bernard Z; Gardner, Judith M

    2015-11-01

    The study of twin behavior offers the opportunity to study differential patterns of social and communicative interactions in a context where the adult partner and same-age peer are equally familiar. We investigated the development of social engagement, communicative gestures, and imitation in 7- to 25-month-old twins. Twin dyads (N=20 pairs) participated in 10-min, semi-structured play sessions, with the mother seated in a chair completing paperwork for half the session, and on the floor with her children for the other half. Overall, twins engaged more with their mothers than with their siblings: they showed objects and imitated speech and object use more frequently when interacting with their mothers than with their siblings. When the mother was otherwise engaged, the twins played with toys separately, observed each other's toy play, or were unengaged. These results demonstrate that adult scaffolding of social interactions supports increased communicative bids even in a context where both familiar peers and adults are available as communicative partners. PMID:26476957

  8. Shorter adult stature increases the impact of risk factors for cognitive impairment: a comparison of two Nordic twin cohorts.

    PubMed

    Laitala, Venla S; Hjelmborg, Jacob; Koskenvuo, Markku; Räihä, Ismo; Rinne, Juha O; Christensen, Kaare; Kaprio, Jaakko; Silventoinen, Karri

    2011-12-01

    We analyzed the association between mean height and old age cognition in two Nordic twin cohorts with different childhood living conditions. The cognitive performance of 4720 twin individuals from Denmark (mean age 81.6 years, SD = 4.59) and Finland (mean age 74.4 years, SD = 5.26) was measured using validated cognitive screens. Taller height was associated with better cognitive performance in Finland (beta-estimates 0.18 SD/10cm, p value < .001, for men and 0.13 SD, p = .008, for women), but this association was not significant in Denmark (beta-estimates 0.0093 SD, p value = .16, for men and 0.0075 SD, p value = .016, for women) when adjusted for age and education/social class. Among Finnish participants higher variability of cognitive performance within shorter height quintiles was observed. Analysis using gene-environment interaction models showed that environmental factors exerted a greater impact on cognitive performance in shorter participants, whereas in taller participants' it was explained mainly by genetic factors. Our results suggest that shorter participants with childhood adversity are more vulnerable to environmental risk factors for cognitive impairment. PMID:22506310

  9. Establishing a twin register in Sri Lanka.

    PubMed

    Sumathipala, A; Fernando, D J; Siribaddana, S H; Abeysingha, M R; Jayasekare, R W; Dissanayake, V H; De Silva, N

    2000-12-01

    Nearly all twin registers are based in developed countries and there is no twin register in the developing world. Our objectives were to initiate the process of establishing a nationwide twin register in Sri Lanka by starting a volunteer register first and working towards a population-based register. Regular newspaper advertisements, feature articles, radio talks, and television programmes were used to publicise a competition for twins, their parents/relatives and friends requesting them to participate by sending in details of twins. The competition ran from 28 March 1997 for a period of 3 months. It offered prizes for three winners selected by drawing lots. Advertisements highlighted the objective of the competition as establishing a twin register for future research and emphasised that informed consent would be obtained for individual research projects. Those who registered comprise 4602 twin pairs (same sex: male--1564, female--1885; different sex--1153), 80 sets of triplets (same sex: male--17, female--31; different sex--42) and two sets of quadruplets (different sex). The oldest twins, triplets, quadruplets are 85, 46, and 5 years old, respectively; 88.0% of twins are less than 30 years old. Although others have previously used media publicity to enrol twins in twin registers, we believe this to be the first time that twins have been enrolled through competition. We have more young twins, and our gender and zygosity proportions after applying Weinburg's rule do not match the proportions expected from a volunteer twin sample. Establishing a twin register for research purposes has proved possible in a developing country. PMID:11463139

  10. The Perfect Pairing: The Adult Learner and the Boutique Winery in the Start-Up Phase

    ERIC Educational Resources Information Center

    Heath-Simpson, Delta F.

    2011-01-01

    The purpose of this phenomenological study was to understand and describe the lived experiences of adult learners who are owners and managers of small winery businesses operating in the start-up phase of the organizational life cycle. The study explored and identified the meaning of adult learning in the entrepreneurial context and its affect on…

  11. Marital Conflict and Conduct Problems in Children of Twins

    ERIC Educational Resources Information Center

    Harden, K. Paige; Turkheimer, Eric; Emery, Robert E.; D'Onofrio, Brian M.; Slutske, Wendy S.; Heath, Andrew C.; Martin, Nicholas G.

    2007-01-01

    The Children-of-Twins design was used to test whether associations between marital conflict frequency and conduct problems can be replicated within the children of discordant twin pairs. A sample of 2,051 children (age 14-39 years) of 1,045 twins was used to estimate the genetic and environmental influences on marital conflict and determine…

  12. Intrauterine growth of twins in Taiwan.

    PubMed

    Teng, R J; Jou, H J; Ho, M M

    1994-01-01

    During the period between January 1, 1980 and December 31, 1991, there was a total of 21,348 live born neonates delivered in our hospital. Among them, there were 368 pairs of twins and 18 sets of triplets. The incidences of twin and triplet pregnancy were 1.76% (one pair in every 57.8 live deliveries) and 0.086% (one set in every 1,164 live deliveries), respectively. The mode of gestational age for all twins in this study was 36.6 +/- 3.2 weeks (36.6 +/- 3.6 weeks for vaginal delivery and 36.7 +/- 2.8 weeks for cesarean section, respectively). Among twins delivered by cesarean section, the birth weight of the first born twin was significantly heavier than the second born twin; however, this difference was not observed for those twins delivered vaginally. Also, the birth weight between male and female was not significantly different. However, for those twin pairs of different sexes, the birth weight for the male twin was significantly heavier than the female co-twin. In those cases the mean birth weight increased steadily as the gestational age increased and plateaued at about the 40th week. Compared to the intrauterine growth curve of the Chinese singleton, the difference started from the 33rd gestational week and reached a significant level at about the 37th gestational week. This may indicate the incipient of the placental insufficiency for multiple pregnancies. The intrauterine growth curve for twin pregnancies may serve as guide for studying the mortality and morbidity of twins in the future.

  13. Australian Twin Registry: 30 years of progress.

    PubMed

    Hopper, John L; Foley, Debra L; White, Paul A; Pollaers, Vincent

    2013-02-01

    The Australian Twin Registry (ATR) is a national volunteer resource of twin pairs and higher-order multiples willing to consider participating in health, medical, and scientific research. The vision of the ATR is 'to realize the full potential of research involving twins to improve the health and well-being of all Australians'. The ATR has been funded continuously by the National Health and Medical Council for more than 30 years. Its core functions entail the recruitment and retention of twin members, the maintenance of an up-to-date database containing members' contact details and baseline information, and the promotion and provision of open access to researchers from all institutes in Australia, and their collaborators, in a fair and equitable manner. The ATR is administered by The University of Melbourne, which acts as custodian. Since the late 1970s the ATR has enrolled more than 40,000 twin pairs of all zygosities and facilitated more than 500 studies that have produced at least 700 peer-reviewed publications from classical twin studies, co-twin control studies, within-pair comparisons, twin family studies, longitudinal twin studies, randomized controlled trials, and epigenetics studies, as well as studies of issues specific to twins. New initiatives include: a Health and Life Style Questionnaire; data collection, management, and archiving using a secure online software program (The Ark); and the International Network of Twin Registries. The ATR's expertise and 30 years of experience in providing services to national and international twin studies has made it an important resource for research across a broad range of disciplines.

  14. Fingerprint recognition with identical twin fingerprints.

    PubMed

    Tao, Xunqiang; Chen, Xinjian; Yang, Xin; Tian, Jie

    2012-01-01

    Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6) images. Compared to the previous work, our contributions are summarized as follows: (1) Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2) Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3) A larger sample (83 pairs) was collected. (4) A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5) A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a) A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b) The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c) For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d) For each of four fingers of identical twins, the probability of having same fingerprint type is similar. PMID:22558204

  15. Fingerprint recognition with identical twin fingerprints.

    PubMed

    Tao, Xunqiang; Chen, Xinjian; Yang, Xin; Tian, Jie

    2012-01-01

    Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6) images. Compared to the previous work, our contributions are summarized as follows: (1) Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2) Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3) A larger sample (83 pairs) was collected. (4) A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5) A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a) A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b) The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c) For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d) For each of four fingers of identical twins, the probability of having same fingerprint type is similar.

  16. Late Language Emergence in 24-Month-Old Twins: Heritable and Increased Risk for Late Language Emergence in Twins

    ERIC Educational Resources Information Center

    Rice, Mabel L.; Zubrick, Stephen R.; Taylor, Catherine L.; Gayán, Javier; Bontempo, Daniel E.

    2014-01-01

    Purpose: This study investigated the etiology of late language emergence (LLE) in 24-month-old twins, considering possible twinning, zygosity, gender, and heritability effects for vocabulary and grammar phenotypes. Method: A population-based sample of 473 twin pairs participated. Multilevel modeling estimated means and variances of vocabulary and…

  17. Common plankton of Twin Lakes, Colorado

    SciTech Connect

    Lieberman, D.M.

    1983-02-01

    A series of studies is being performed to evaluate the effects of the Mt. Elbert Pumped-Storage Powerplant on the ecology of Twin Lakes. Twin Lakes are a pair of connected dimictic lakes, formed as the result of glacial action on alluvial deposits. This report presents a taxonomic species study of the common plankton collected since 1974 from Twin Lakes. A total of 11 zooplankters and 14 phytoplankters were identified from the limnetic zone of Twin Lakes and the associated Mt. Elbert Forebay. The four divisions of zooplankton included four species of Rotifera (rotifer), three species of Copepoda (copepod), three species of Cladocera (cladoceran), and one species of Mysidacea (opossum shrimp).

  18. The Boston University Twin Project (BUTP).

    PubMed

    Saudino, Kimberly J; Asherson, Philip

    2013-02-01

    The Boston University Twin Project (BUTP) is a multi-method, multi-situation, longitudinal study of early child temperament and related behaviors. The first phase of this project focused primarily on activity level and comprised over 300 twin pairs assessed in the home and lab at ages 2 and 3. Subject recruitment, sample characteristics, and study procedures are described. A second phase broadens our focus to the development of multiple temperament dimensions and developmental outcomes in a new cohort of 300 twin pairs to be assessed at 3, 4, and 5 years of age. Recruitment is currently underway.

  19. Investigating Unique Environmental Influences of Parenting Practices on Youth Anxiety: A Monozygotic Twin Differences Study

    ERIC Educational Resources Information Center

    Chen, Jie; Yu, Jing; Zhang, Jianxin

    2016-01-01

    The associations between parenting practices and adolescent anxiety symptoms were examined in both individual and monozygotic (MZ) twin differences levels. Participants were 804 pairs of Chinese MZ adolescent twins aged 10-18 years (M = 13.57, SD = 2.67, 52% females). Twins' anxiety symptoms were assessed by self- and parent-reports. Twins also…

  20. Human heart rate: Heritability of resting and stress values in twin pairs, and influence of genetic variation in the adrenergic pathway at a micro-RNA motif in the 3’-UTR of cytochrome b561 (CYB561)

    PubMed Central

    Zhang, Kuixing; Deacon, Dekker C.; Rao, Fangwen; Schork, Andrew J.; Fung, Maple M.; Waalen, Jill; Schork, Nicholas J.; Nievergelt, Caroline M.; Chi, Neil C.; O'Connor, Daniel T.

    2013-01-01

    Objective To understand the role of genetic variation in the catecholamine biosynthetic pathway for control of human heart rate (HR). Background Human HR is an integrated cardiovascular trait predictive of morbidity and survival. Since the autonomic pathway exerts rapid control over the heart, we probed the role of heredity in control of HR, focusing on a component of the autonomic sympathetic pathway already predictive of outflow responses: Cytochrome b561 (CYB561), the electron shuttle in catecholamine vesicle membranes for transmitter biosynthesis. Methods We studied hereditary control of HR with the twin pair design, at rest and during environmental (cold) stress. SNP disruption of a micro-RNA recognition motif in the human CYB561 3’-UTR was identified computationally, and its differential effect on gene expression was demonstrated in a transfected luciferase reporter / 3’-UTR variant. We exposed of stem-cell-derived human embryoid bodies to the micro-RNA mimic or antagomir oligonucleotides, and observed effects on contraction rate in proto-hearts. Results Substantial heritability (h2) was demonstrated, by twin pair variance components, for both basal/resting HR (h2=50.9±6.4% of trait variation, p=2.47E-10) and stress-augmented HR (h2=55.1±5.9%, p=8.79E-13), and the two HR traits shared genetic determination (genetic covariance ρG=0.747±0.058, p=2.85E-09). CYB561 displayed one common genetic variant in the transcript region: A+1485G (rs3087776), in the 3’-UTR, 1485 bp downstream of the termination codon, in a conserved region, with the A-allele ancestral in primates. In a twin/sibling sample (n=576), A+1485G influenced HR, both at rest (p=0.010) and after environmental stress (p=0.002), with the minor (A) allele displaying a recessive effect with lower HR. The effect of A+1485G on HR was extended by meta-analysis into two additional population samples (total n=2579), and the influence remained directionally consistent and significant (p=0.007). A+1485

  1. Is marriage a buzzkill? A twin study of marital status and alcohol consumption.

    PubMed

    Dinescu, Diana; Turkheimer, Eric; Beam, Christopher R; Horn, Erin E; Duncan, Glen; Emery, Robert E

    2016-09-01

    Married adults have consistently been found to drink less than their single or divorced counterparts. This correlation may not be causal, however, as people nonrandomly "select" into marriage and into alcohol use. The current study uses a sample of 2,425 same-sex twin pairs (1,703 MZ; 722 DZ) to control for genetic and shared environmental selection, thereby eliminating a great many third variable, alternative explanations to the hypothesis that marriage causes less drinking. Married twins were compared with their single, divorced, and cohabiting cotwins on drinking frequency and quantity. Married cotwins consumed fewer alcoholic beverages than their single or divorced cotwins, and drank less frequently than their single cotwins. Alcohol use patterns did not differ among married and cohabiting twins. These findings provide strong evidence that intimate relationships cause a decline in alcohol consumption. (PsycINFO Database Record PMID:27336180

  2. Sonar cephalometry in twin pregnancy: discordancy of the biparietal diameter after 28 weeks' gestation.

    PubMed

    Leveno, K J; Santos-Ramos, R; Duenhoelter, J H; Reisch, J S; Whalley, P J

    1980-11-15

    Sonar measured biparietal diameter (BPD) differences of twin paires were examined in 123 twin pregnancies at or beyond 28 weeks' gestation. Among 117 liveborn sets, the risk of a twin infant being small for gestational age was threefold greater when paired BPD differences were 5 mm or more compared to 4 mm or less. The incidence of fetal death increased from 2.7% for twin pairs with 0 to 6 mm BPD differences to 20% when the difference was 7 mm or more. Sonar cephalometry may be helpful in the antepartum evaluation of twin pregnancies, although detection of BPD discordancy does not preclude normal twin outcome.

  3. Neonatal morbidity in growth-discordant monochorionic twins: comparison between the larger and the smaller twin.

    PubMed

    Lopriore, Enrico; Sluimers, Carolien; Pasman, Suzanne A; Middeldorp, Johanna M; Oepkes, Dick; Walther, Frans J

    2012-08-01

    Fetal growth restriction in singletons has been shown to enhance fetal lung maturation and reduce the risk of respiratory distress syndrome due to increased endogenous steroid production. However, data on lung maturation in growth-discordant monochorionic (thus, identical) twins are lacking. Our objective was to compare the risk of severe neonatal morbidity between the larger and the smaller twin in monochorionic twins with birth weight discordance (BWD). We included in the study all consecutive monochorionic diamniotic pregnancies with severe BWD (≥25%) and two live-born twins delivered at our center (n=47 twin pairs). We compared the incidence of neonatal morbidity, particularly respiratory distress syndrome (RDS), and cerebral lesions between the larger and the smaller co-twin. The incidence of severe neonatal morbidity in the larger and smaller twin was 38% (18/47) and 19% (9/47), respectively (odds ratio (OR) 2.66, 95% confidence interval (CI) 0.94-7.44) and was due primarily to the higher incidence of RDS, 32% (15/47) and 6% (3/47), respectively (OR 6.88, 95% CI 1.66-32.83). In conclusion, this study shows that the larger twin in monochorionic twin pairs with BWD is at increased risk of severe neonatal morbidity, particularly RDS, compared to the smaller twin. PMID:22854118

  4. Birth/Death/Rebirth: Pairing Young Adult and Classic Novels To Teach Situational Archetypes.

    ERIC Educational Resources Information Center

    Sanderson, Christine

    2001-01-01

    Notes that the use of Young Adult literature to introduce the complex literary concept of the archetype is ideally suited to teachers of gifted students in high school classrooms. Discusses how once students understand the concept of archetypes in literature, they can begin to make deeper connections among all of the literary works that they read.…

  5. Longitudinal Stability of Genetic and Environmental Influences on the Association between Diurnal Preference and Sleep Quality in Young Adult Twins and Siblings.

    PubMed

    Barclay, Nicola L; Rowe, Richard; O'Leary, Rachael; Bream, Danielle; Gregory, Alice M

    2016-08-01

    Overlapping genetic influences have been implicated in diurnal preference and subjective sleep quality. Our overall aim was to examine overlapping concurrent and longitudinal genetic and environmental effects on diurnal preference and sleep quality over ~5 years. Behavioral genetic analyses were performed on data from the longitudinal British G1219 study of young adult twins and nontwin siblings. A total of 1556 twins and siblings provided data on diurnal preference (Morningness-Eveningness Questionnaire) and sleep quality (Pittsburgh Sleep Quality Index) at time 1 (mean age = 20.30 years, SD = 1.76; 62% female), and 862 participated at time 2 (mean age = 25.30 years, SD = 1.81; 66% female). Preference for eveningness was associated with poorer sleep quality at both time points (r = 0.25 [95% confidence intervals {CIs} = 0.20-0.30] and r = 0.21 [CI = 0.15-0.28]). There was substantial overlap in the genetic influences on diurnal preference and sleep quality individually, across time (genetic correlations [rAs]: 0.64 [95% CI = 0.59-0.67] and 0.48 [95% CI = 0.42-.053]). There were moderate genetic correlations between diurnal preference and sleep quality concurrently and longitudinally (rAs = 0.29-0.60). Nonshared environmental overlap was substantially smaller for all cross-phenotype associations (nonshared environmental correlations (rEs) = -0.02 to 0.08). All concurrent and longitudinal associations within and between phenotypes were largely accounted for by genetic factors (explaining between 60% and 100% of the associations). All shared environmental effects were nonsignificant. Nonshared environmental influences played a smaller role on the associations between phenotypes (explaining between -0.06% and 40% of the associations). These results suggest that to some extent, similar genes contribute to the stability of diurnal preference and sleep quality throughout young adulthood but also that different genes play a part over this relatively short time frame

  6. Effects of paired-object affordance in search tasks across the adult lifespan.

    PubMed

    Wulff, Melanie; Stainton, Alexandra; Rotshtein, Pia

    2016-06-01

    The study investigated the processes underlying the retrieval of action information about functional object pairs, focusing on the contribution of procedural and semantic knowledge. We further assessed whether the retrieval of action knowledge is affected by task demands and age. The contribution of procedural knowledge was examined by the way objects were selected, specifically whether active objects were selected before passive objects. The contribution of semantic knowledge was examined by manipulating the relation between targets and distracters. A touchscreen-based search task was used testing young, middle-aged, and elderly participants. Participants had to select by touching two targets among distracters using two search tasks. In an explicit action search task, participants had to select two objects which afforded a mutual action (e.g., functional pair: hammer-nail). Implicit affordance perception was tested using a visual color-matching search task; participants had to select two objects with the same colored frame. In both tasks, half of the colored targets also afforded an action. Overall, middle-aged participants performed better than young and elderly participants, specifically in the action task. Across participants in the action task, accuracy was increased when the distracters were semantically unrelated to the functional pair, while the opposite pattern was observed in the color task. This effect was enhanced with increased age. In the action task all participants utilized procedural knowledge, i.e., selected the active object before the passive object. This result supports the dual-route account from vision to action. Semantic knowledge contributed to both the action and the color task, but procedural knowledge associated with the direct route was primarily retrieved when the task was action-relevant. Across the adulthood lifespan, the data show inverted U-shaped effects of age on the retrieval of action knowledge. Age also linearly increased the

  7. Head Circumferences in Twins with and without Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Froehlich, Wendy; Cleveland, Sue; Torres, Andrea; Phillips, Jennifer; Cohen, Brianne; Torigoe, Tiffany; Miller, Janet; Fedele, Angie; Collins, Jack; Smith, Karen; Lotspeich, Linda; Croen, Lisa A.; Ozonoff, Sally; Lajonchere, Clara; Grether, Judith K.; Hallmayer, Joachim

    2013-01-01

    To determine the genetic relationship between head circumference (HC) and Autism Spectrum Disorders (ASDs). Twin pairs with at least one twin with an ASD were assessed. HCs in affected and unaffected individuals were compared, as were HC correlations in monozygotic and dizygotic pairs. 404 subjects, ages 4-18, were included. 20% of males and 27%…

  8. Asthma discordance in twins is linked to epigenetic modifications of T cells.

    PubMed

    Runyon, R Scott; Cachola, Leslie M; Rajeshuni, Nitya; Hunter, Tessa; Garcia, Marco; Ahn, Regina; Lurmann, Fred; Krasnow, Ruth; Jack, Lisa M; Miller, Rachel L; Swan, Gary E; Kohli, Arunima; Jacobson, Amanda C; Nadeau, Kari C

    2012-01-01

    T cells mediate the inflammatory responses observed in asthma among genetically susceptible individuals and have been suspected to be prone to epigenetic regulation. However, these relationships are not well established from past clinical studies that have had limited capacity to control for the effects of variable genetic predisposition and early environmental exposures. Relying on a cohort of monozygotic twins discordant for asthma we sought to determine if epigenetic modifications in T cells were associated with current asthma and explored whether such modifications were associated with second hand smoke exposures. Our study was conducted in a monozygotic twin cohort of adult twin pairs (n = 21) all discordant for asthma. Regulatory T cell (Treg) and effector T cell (Teff) subsets were assessed for levels of cellular function, protein expression, gene expression and CpG methylation within Forkhead box P3 (FOXP3) and interferon gamma-γ (IFNγ) loci. Comparisons by asthma and current report of exposure to second hand smoke were made. Treg from asthmatic discordant twins demonstrated decreased FOXP3 protein expression and impaired Treg function that was associated with increased levels of CpG methylation within the FOXP3 locus when compared to their non-asthmatic twin partner. In parallel, Teff from discordant asthmatic twins demonstrated increased methylation of the IFNγ locus, decreased IFNγ expression and reduced Teff function when compared to Teff from the non-asthmatic twin. Finally, report of current exposure to second hand smoke was associated with modifications in both Treg and Teff at the transcriptional level among asthmatics. The results of the current study provide evidence for differential function of T cell subsets in monozygotic twins discordant for asthma that are regulated by changes in DNA methylation. Our preliminary data suggest exposure to second hand smoke may augment the modified T cell responses associated with asthma. PMID:23226205

  9. Parenting and risk for mood, anxiety and substance use disorders: a study in population-based male twins

    PubMed Central

    Gardner, Charles O.; Kendler, Kenneth S.; Hettema, John M.

    2013-01-01

    Background Previous studies consistently identified a relationship between parenting behavior and psychopathology. In this study, we extended prior analyses performed in female twins to a large sample of twins from male–male pairs. Methods We used interview data on 2,609 adult male twins from a population-based twin registry. We examined the association between three retrospectively reported parenting dimensions (coldness, protectiveness, and authoritarianism) and lifetime history of seven common psychiatric and substance use disorders. Using univariate structural equation modeling, we also examined the influence of the genetic and environmental factors on parenting. Results Examined individually, coldness was consistently associated with risk for a broad range of adult psychopathology. Averaged odds of psychiatric disorders associated with parenting were increased between 26 and 36 %. When the three parenting dimensions were examined together, coldness remained significant for major depression, phobia, and generalized anxiety disorder. Controlling for other disorders, the associations between the parenting dimensions and psychopathology were non-specific. Twin fitting model demonstrated that modest heritability accounted for parenting, whereas most variance resulted from the non-shared environment. Conclusions Based on our current and prior findings, there is broad similarity in the impact of parenting on adult psychopathology between men and women. PMID:23344783

  10. Zygosity and intrauterine growth of twins.

    PubMed

    Grennert, L; Persson, P H; Gennser, G; Gullberg, B

    1980-06-01

    Six hundred seventy-eight sonar measurements of the fetal biparietal diameter (BPD) were used to assess the intrauterine growth of 182 twins between 18 and 40 weeks' gestation. These values, as well as the weight and body length at birth, were related to the zygosity, which was determined by sex of the infants, histologic examination of placenta, or blood grouping. The mean BPD of twin 1 was larger than that of twin 2 in both monozygotic and dizygotic pairs throughout the study period (P less than .001). The size of BPD of the dizygotic infants exceeded that of the monozygotic among both twin 1 (P less than .001) and twin 2 (P less than .001). The absolute intrapair differences of birth length and weight were larger among dizygotic than among monozygotic twins. These findings suggest that in late pregnancy a substantial one-way intertwin transfusion among monochorial twins does not occur frequently enough to mask the inherent genetically determined similarity between the twins. The appearance already in the second trimester of the difference in the longitudinally monitored BPD between monozygotic and dizygotic twins suggests that the discrepancy is determined early in gestation.

  11. B-cell repertoire responses to varicella-zoster vaccination in human identical twins.

    PubMed

    Wang, Chen; Liu, Yi; Cavanagh, Mary M; Le Saux, Sabine; Qi, Qian; Roskin, Krishna M; Looney, Timothy J; Lee, Ji-Yeun; Dixit, Vaishali; Dekker, Cornelia L; Swan, Gary E; Goronzy, Jörg J; Boyd, Scott D

    2015-01-13

    Adaptive immune responses in humans rely on somatic genetic rearrangements of Ig and T-cell receptor loci to generate diverse antigen receptors. It is unclear to what extent an individual's genetic background affects the characteristics of the antibody repertoire used in responding to vaccination or infection. We studied the B-cell repertoires and clonal expansions in response to attenuated varicella-zoster vaccination in four pairs of adult identical twins and found that the global antibody repertoires of twin pair members showed high similarity in antibody heavy chain V, D, and J gene segment use, and in the length and features of the complementarity-determining region 3, a major determinant of antigen binding. These twin similarities were most pronounced in the IgM-expressing B-cell pools, but were seen to a lesser extent in IgG-expressing B cells. In addition, the degree of antibody somatic mutation accumulated in the B-cell repertoire was highly correlated within twin pair members. Twin pair members had greater numbers of shared convergent antibody sequences, including mutated sequences, suggesting similarity among memory B-cell clonal lineages. Despite these similarities in the memory repertoire, the B-cell clones used in acute responses to ZOSTAVAX vaccination were largely unique to each individual. Taken together, these results suggest that the overall B-cell repertoire is significantly shaped by the underlying germ-line genome, but that stochastic or individual-specific effects dominate the selection of clones in response to an acute antigenic stimulus. PMID:25535378

  12. The National Longitudinal Study of Adolescent to Adult Health (Add Health) Sibling Pairs Genome-Wide Data

    PubMed Central

    McQueen, Matthew B.; Boardman, Jason D.; Domingue, Benjamin W.; Smolen, Andrew; Tabor, Joyce; Killeya-Jones, Ley; Halpern, Carolyn T.; Whitsel, Eric A.; MullanHarris, Kathleen

    2014-01-01

    Here we provide a detailed description of the genome-wide information available on the National Longitudinal Study of Adolescent to Adult Health (Add Health) sibling pair subsample (Harris et al., 2012). A total of 2020 samples were genotyped (including duplicates) arising from 1946 Add Health individuals from the sibling pairs subsample. After various steps for quality control (QC) and quality assurance (QA), we have high quality genome-wide data available on 1,888 individuals. In this report, we first highlight theQC and QA steps that were taken to prune the data of poorly performing samples and genetic markers. We further estimate the pairwise biological relationships using genome-wide data and compare those estimates to the assumed relationships in Add Health. Additionally, using genome-wide data from knownregional reference populations from Europe, West Africa, North and South America, Japan and China, weestimate the relative genetic ancestry of the respondents. Finally, rather than conducting a traditional cross-sectional genome-wide association study (GWAS) of body mass index (BMI), we opted to utilize the extensivepublicly available genome-wide information to conduct a weighted genome-wide association study (GWAS) of longitudinal BMI while accounting for both family and ethnic variation. PMID:25378290

  13. Twinning of dodecanedicarboxylic acid

    NASA Technical Reports Server (NTRS)

    Sen, R.; Wilcox, W. R.

    1986-01-01

    Twinning of 1,10-dodecanedicarboxyl acid (DDA) was observed in 0.1 mm thick films with a polarizing microscope. Twins originated from polycrystalline regions which tended to nucleate on twin faces, and terminated by intersection gone another. Twinning increased dramatically with addition of organic compounds with a similar molecular size and shape. Increasing the freezing rate, increasing the temperature gradient, and addition of silica particles increased twinning. It is proposed that twins nucleate with polycrystals and sometimes anneal out before they become observable. The impurities may enhance twinning either by lowering the twin energy or by adsorbing on growing faces.

  14. Twin-to-twin transfusion syndrome

    MedlinePlus Videos and Cool Tools

    ... Transfusion Syndrome, or TTTS, is a disease of the placenta. This condition affects twins or other multiples ... containing blood vessels going from one baby to the other. Blood from the smaller "donor" twin is ...

  15. Monochorionic dizygous twins presenting with blood chimerism and discordant sex.

    PubMed

    Smeets, Dominique; van Vugt, John M G; Gomes, Ingrid; van den Heuvel, Simone; van Heijst, Arno; Reuss, Annette; Claahsen-van der Grinten, Hedi L

    2013-08-01

    Monochorionic dizygous twins are probably more frequent than considered previously as many cases remain unrecognized, especially when the children have the same sex. Here we present a pair of dizygous, sex-discordant monochorionic twins who were conceived after artificial insemination. Histological examination of the placenta and extensive genetic studies of the healthy boy and girl clearly proved that they indeed were monochorionic dizygous twins with a fully joined blood circulation. We conclude that when counseling parents expecting monochorionic twins of discordant sex, not only a disorder of sexual differentiation in one of the twins should be addressed but also the possibility of dizygosity with a completely normal (sexual) development of both children.

  16. What Virtual Twins Reveal About General Intelligence and Other Behaviors

    PubMed Central

    Segal, Nancy L.; McGuire, Shirley A.; Stohs, Joanne Hoven

    2011-01-01

    The Fullerton Virtual Twin Study has been assessing the behaviors of an unusual sibship since 1982. Virtual twins (VTs) are same-age, unrelated siblings reared together since infancy. They replicate the rearing situation of twins but without the genetic link, enabling direct assessment of shared environmental effects on behavior. An updated analysis of IQ data, based on an increased sample of 142 VT pairs (7.87 years, SD=8.22), is presented. Intraclass correlations of .28 (IQ) and .11 (subtest profile) indicated modest shared environmental influences on intelligence. Findings from the Twins, Adoptees, Peers and Siblings (TAPS) project that studies virtual twins and other kinships are described. PMID:22711965

  17. Maternal serum alpha fetoprotein in monozygotic and dizygotic twin pregnancies.

    PubMed

    Thom, H; Buckland, C M; Campbell, A G; Thompson, B; Farr, V

    1984-01-01

    Maternal serum alpha-fetoprotein (MSAFP) values in the second trimester have been related to pregnancy outcome for 100 normal twin pairs, 42 monozygous (MZ) and 58 dizygous (DZ), liveborn after 28 weeks gestation. The median MSAFP value was 1.9 multiples of the median value (MOM) for uncomplicated singleton pregnancies. Both very low and very high MSAFP values were associated with twins of low birthweight. MSAFP values were higher in MZ than DZ twin pregnancies particularly those with dizygotes of like-sex. This effect was even more marked when only dichorionic like-sex twin pairs were compared. PMID:6209699

  18. The occurrence of gonadal dysgenesis in association with monozygotic twinning.

    PubMed Central

    Karp, L; Bryant, J I; Tagatz, G; Giblett, E; Fialkow, P J

    1975-01-01

    A case is presented of a monozygotic twin pair, discordant for phenotypic sex, in which the female member showed gonadal dysgenesis and chromosomal mosaicism. Review of the pertinent literature reveals that in monozygotic twin pairs, phenotypic and karyotypic concordance is the usual occurrence for Down's and Klinefelter's syndromes, whereas discordance often accompanies gonadal dysgenesis. Mosaicism is a frequent concomitant of gonadal dysgenesis in monozygotic twins. Our case strengthens the probability of a real association between mosaicism and monozygotic twinning in gonadal dysgenesis. Images PMID:1121022

  19. A twin study on age-related macular degeneration.

    PubMed Central

    Meyers, S M

    1994-01-01

    A prospective twin study on age-related macular degeneration (AMD) recruited 83 monozygotic pairs, 28 dizygotic pairs, and one triplet set from 1986 through 1993. Zygosity was determined by genetic testing of red cell markers, HLA antigens, or specific DNA loci. There were no twin pairs in which I collected data on only one twin. To decrease ascertainment bias, after 1991 the recruitment notice did not mention AMD, and I did not ask about a history of eye disease before the eye examination. Because of this, twin pairs recruited from 1986 through 1991 were statistically analyzed separately from those after January 1, 1992. From 1986 through 1991, 23 twin pairs were recruited; 11 monozygotic and 2 dizygotic pairs had nonAMD retinal changes or no retinal abnormalities, 9 monozygotic pairs with AMD were all concordant, and 1 dizygotic pair was discordant for basal laminar drusen. The concordance rate of AMD did not differ significantly between monozygotic and dizygotic twin pairs (P = .10) for 1986 through 1991. In 1992 and 1993, 88 twin pairs and one triplet set were recruited; 49 monozygotic and 19 dizygotic pairs had nonAMD retinal changes or no retinal abnormalities, 14 monozygotic pairs with AMD were all concordant, and 2 of 7 dizygotic pairs were concordant for AMD. The nonidentical triplets (1 with and 2 without AMD) were categorized as one of the discordant dizygotic pairs in the statistical evaluation. In nontwin age-matched (within 2 or 5 years of age) or age- and sex-matched sibling pairs the concordance rate of AMD ranged from 16% to 25%. The concordance rate of AMD was significantly higher in monozygotic than in dizygotic twins (P = .001) for 1992 and 1993. The concordance rate was higher for monozygotic twin pairs recruited in 1992 and 1993 than in any of the four subsets of nontwin age-method or age- and sex-matched sibling pairs (P < .0001). Overall, from 1986 through 1993, 23 of 23 monozygotic and 2 of 8 dizygotic twin pairs were concordant for AMD

  20. Twin concordance and sibling recurrence rates in multiple sclerosis

    PubMed Central

    Willer, C. J.; Dyment, D. A.; Risch, N. J.; Sadovnick, A. D.; Ebers, G. C.

    2003-01-01

    Size and ascertainment constraints often limit twin studies to concordance comparisons between identical and fraternal twins. Here we report the final results of a longitudinal, population-based study of twins with multiple sclerosis (MS) in Canada. Bias was demonstrably minimized, and an estimated 75% of all Canadian MS twin pairs were ascertained, giving a sample sufficiently large (n = 370) to permit additional informative comparisons. Twinning was not found to affect prevalence, and twins with MS did not differ from nontwins for DR15 allele frequency nor for MS risk to their siblings. Probandwise concordance rates of 25.3% (SE ± 4.4) for monozygotic (MZ), 5.4% (±2.8) for dizygotic (DZ), and 2.9% (±0.6) for their nontwin siblings were found. MZ twin concordance was in excess of DZ twin concordance. The excess concordance in MZ was derived primarily from like-sexed female pairs with a probandwise concordance rate of 34 of 100 (34 ± 5.7%) compared with 3 of 79 (3.8 ± 2.8%) for female DZ pairs. We did not demonstrate an MZ/DZ difference in males, although the sample size was small. We observed a 2-fold increase in risk to DZ twins over nontwin siblings of twins, but the difference was not significant. PMID:14569025

  1. The Sri Lankan Twin Registry: 2012 update.

    PubMed

    Sumathipala, Athula; Siribaddana, Sisira; Hotopf, Mathew; McGuffin, Peter; Glozier, Nick; Ball, Harriet; Kovas, Yulia; Rijsdijk, Fruhling; Yatawara, Lalani; Pariante, Carmine; Zavos, Helena; Siriwardhana, Chesmal; Pannala, Gayani; Jayaweera, Kaushalya; Adikari, Anushka; Gunewardane, Dinesha

    2013-02-01

    The Sri Lankan Twin Registry (SLTR), established in 1997, is a unique resource for twin and genetic research in a low- and middle-income country (LMIC). It comprises of a volunteer cohort of 14,120 twins (7,060 pairs) and 119 sets of triplets, and a population-based cohort of 19,040 (9,520 pairs) twins and 89 sets of triplets. Several studies have been conducted using this registry, including the Colombo Twin and Singleton Study (CoTaSS 1; 4,387 twins, 2,311 singletons), which have explored the prevalence and heritability of a range of psychiatric disorders as well as gene-environmental interplay. Currently, a follow-up study (CoTaSS 2) of the same cohort is underway, looking at the prevalence and interrelationship of key cardiovascular and metabolic risk markers (e.g., metabolic syndrome). A significant feature of CoTaSS 2 is the establishment of a biobank. Current SLTR work is extending beyond mental health and the interface between mental and physical health to new horizons, extending collaborations with the wider global twin research community. Ethics and governance have been given special emphasis in the initiative. Capacity building and public engagement are two crucial components. Establishment of a state-of-the-art genetic laboratory was a major accomplishment. SLTR is a classic showcase of successful North-South partnership in building a progressive research infrastructure in a LMIC. PMID:23302519

  2. Understanding the covariation of tics, attention-deficit/hyperactivity, and obsessive-compulsive symptoms: A population-based adult twin study.

    PubMed

    Pinto, Rebecca; Monzani, Benedetta; Leckman, James F; Rück, Christian; Serlachius, Eva; Lichtenstein, Paul; Mataix-Cols, David

    2016-10-01

    Chronic tic disorders (TD), attention-deficit/hyperactivity-disorder (ADHD), and obsessive-compulsive disorder (OCD) frequently co-occur in clinical and epidemiological samples. Family studies have found evidence of shared familial transmission between TD and OCD, whereas the familial association between these disorders and ADHD is less clear. This study aimed to investigate to what extent liability of tics, attention-deficit/hyperactivity, and obsessive-compulsive symptoms is caused by shared or distinct genetic or environmental influences, in a large population-representative sample of Swedish adult twins (n = 21,911). Tics, attention-deficit/hyperactivity, and obsessive-compulsive symptoms showed modest, but significant covariation. Model fitting suggested a latent liability factor underlying the three phenotypes. This common factor was relatively heritable, and explained significantly less of the variance of attention-deficit/hyperactivity symptom liability. The majority of genetic variance was specific rather than shared. The greatest proportion of total variance in liability of tics, attention-deficit/hyperactivity, and obsessive-compulsive symptoms was attributed to specific non-shared environmental influences. Our findings suggest that the co-occurrence of tics and obsessive-compulsive symptoms, and to a lesser extent attention-deficit/hyperactivity symptoms, can be partly explained by shared etiological influences. However, these phenotypes do not appear to be alternative expressions of the same underlying genetic liability. Further research examining sub-dimensions of these phenotypes may serve to further clarify the association between these disorders and identify more genetically homogenous symptom subtypes. © 2016 Wiley Periodicals, Inc.

  3. Heritable breast cancer in twins

    PubMed Central

    Mack, T M; Hamilton, A S; Press, M F; Diep, A; Rappaport, E B

    2002-01-01

    Known major mutations such as BRCA1/2 and TP53 only cause a small proportion of heritable breast cancers. Co-dominant genes of lower penetrance that regulate hormones have been thought responsible for most others. Incident breast cancer cases in the identical (monozygotic) twins of representative cases reflect the entire range of pertinent alleles, whether acting singly or in combination. Having reported the rate in twins and other relatives of cases to be high and nearly constant over age, we now examine the descriptive and histological characteristics of the concordant and discordant breast cancers occurring in 2310 affected pairs of monozygotic and fraternal (dizygotic) twins in relation to conventional expectations and hypotheses. Like other first-degree relatives, dizygotic co-twins of breast cancer cases are at higher than usual risk (standardised incidence ratio (SIR)=1.7, CI=1.1–2.6), but the additional cases among monozygotic co-twins of cases are much more numerous, both before and after menopause (SIR=4.4, CI=3.6–5.6), than the 100% genetic identity would predict. Monozygotic co-twin diagnoses following early proband cancers also occur more rapidly than expected (within 5 years, SIR=20.0, CI=7.5–53.3). Cases in concordant pairs represent heritable disease and are significantly more likely to be oestrogen receptor-positive than those of comparable age from discordant pairs. The increase in risk to the monozygotic co-twins of cases cannot be attributed to the common environment, to factors that cumulate with age, or to any aggregate of single autosomal dominant mutations. The genotype more plausibly consists of multiple co-existing susceptibility alleles acting through heightened susceptibility to hormones and/or defective tumour suppression. The resultant class of disease accounts for a larger proportion of all breast cancers than previously thought, with a rather high overall penetrance. Some of the biological characteristics differ from those of

  4. Head Circumferences in Twins With and Without Autism Spectrum Disorders

    PubMed Central

    Cleveland, Sue; Torres, Andrea; Phillips, Jennifer; Cohen, Brianne; Torigoe, Tiffany; Miller, Janet; Fedele, Angie; Collins, Jack; Smith, Karen; Lotspeich, Linda; Croen, Lisa A.; Ozonoff, Sally; Lajonchere, Clara; Grether, Judith K.; Hallmayer, Joachim

    2013-01-01

    To determine the genetic relationship between head circumference (HC) and Autism Spectrum Disorders (ASDs). Twin pairs with at least one twin with an ASD were assessed. HCs in affected and unaffected individuals were compared, as were HC correlations in monozygotic and dizygotic pairs. 404 subjects, ages 4–18, were included. 20 % of males and 27 % of females with an ASD had macrocephaly. Unaffected co-twins showed similar rates (15 % of males and 22 % of females). Statistical analysis revealed no significant difference in HCs between affected and unaffected twins. Twins with ASDs and unaffected co-twins have similar HCs and increased rates of macrocephaly. Correlations demonstrated partial inheritance of HCs. Thus, macrocephaly may represent an endophenotype in ASDs. PMID:23321801

  5. The effects of sibling relationships on social adjustment among Japanese twins compared with singletons.

    PubMed

    Nozaki, Mari; Fujisawa, Keiko K; Ando, Juko; Hasegawa, Toshikazu

    2012-12-01

    This study examined the link between sibling relationships and children's social adjustment by comparing twin siblings and siblings with different ages (singleton siblings}, and clarified the role of reciprocity in sibling relationships on children's social development. Mothers of 58 monozygotic twin pairs, 48 dizygotic twin pairs, and 86 singleton sibling pairs reported their children's sibling relationships and social adjustment.This study showed that the effects of sibling relationships on the prosocial behaviors and conduct problems of each child are stronger for twins than for singleton siblings. Moreover, positivity toward one's sibling increased peer problems only among monozygotic twins. The opposite tendency was present among dizygotic twins and singleton siblings. This study suggests the importance for children's social development of having many interactions with siblings and establishing reciprocity in sibling relationships. Moreover, our results suggest that the quality of sibling relationships among monozygotic twins may be different from those among dizygotic twins and singleton siblings.

  6. The TWIN-E project in emotional wellbeing: study protocol and preliminary heritability results across four MRI and DTI measures.

    PubMed

    Gatt, Justine M; Korgaonkar, Mayuresh S; Schofield, Peter R; Harris, Anthony; Clark, C Richard; Oakley, Karen L; Ram, Kaushik; Michaelson, Hope; Yap, Sarsha; Stanners, Melinda; Wise, Vikki; Williams, Leanne M

    2012-06-01

    Despite the significant advancements being made in the neurogenetics for mental health, the identification and validation of potential endophenotype markers of risk and resilience remain to be confirmed. The TWIN-E study (The Twin study in Wellbeing using Integrative Neuroscience of Emotion) aims to validate endophenotype markers of mental health across cognitive, brain, and autonomic measures by testing the heritability, clinical plausibility, and reliability of each of these measures in a large adult twin cohort. The specific gene and environmental mechanisms that moderate prospective links between endophenotype-phenotype markers and the final outcome of wellbeing will also be identified. TWIN-E is a national prospective study with three phases: I) baseline testing on a battery of online questionnaires and cognitive tasks, and EEG, MRI, and autonomic testing; II) 12-month follow-up testing on the online assessments; and III) randomized controlled trial of brain training. Minimum target numbers include 1,500 male/female twins (18-65 years) for the online assessments (Phase I and II), 300 twins for the EEG testing component, and 244 twins for the MRI testing component. For Phase III, each twin out of the pair will be randomized to either the treatment or waitlist control group to test the effects of brain training on mental health over a 30-day period, and to confirm the gene-environment and endophenotype contributions to treatment response. Preliminary heritability results are provided for the first 50% of the MRI subgroup (n = 142) for the grey matter volume, thickness, and surface area measures, and white matter diffuse tensor imaging fractional anisotropy. PMID:22856376

  7. Concordance for neuroblastoma in monozygotic twins: case report and review of the literature.

    PubMed

    Tajiri, Tatsuro; Souzaki, Ryota; Kinoshita, Yoshiaki; Tanaka, Sakura; Koga, Yuhki; Suminoe, Aiko; Hara, Toshiro; Kohashi, Kenichi; Oda, Yoshinao; Masumoto, Kouji; Ohira, Miki; Nakagawara, Akira; Taguchi, Tomoaki

    2010-12-01

    The patients were infant male twins born by cesarean delivery following a healthy pregnancy at 36 weeks' gestation to unrelated parents. At 4 months of age, twin 2 presented with hepatomegaly and a right suprarenal mass. Resection of an adrenal tumor and a liver tumor biopsy were performed. Twin 1 had no symptoms at 4 months of age. Screening by abdominal ultrasonography showed multiple masses in the liver but no adrenal mass. Metaiodobenzylguanidine scintigraphy showed positive findings in multiple liver masses. A laparoscopic biopsy for a liver tumor was performed. All primary tumor and liver tumor specimens from twin 2 and the liver tumor of twin 1 had the same histologic classification of neuroblastoma and nearly identical genetic aberrations, including a chromosome gain or loss using array-comparative genomic hybridization. From these clinical and pathologic findings and genetic analyses, we strongly demonstrate the transplacental metastatic spread from twin 2 to twin 1. In the literature, 9 pairs of concordant twin neuroblastomas, including the current twin, have been presented; and the clinical findings of 5 twin pairs may represent placental metastases from one twin with congenital neuroblastoma to the other twin. This study is the first report presenting the possibility of twin-to-twin metastasis in monozygotic twins with neuroblastoma based on an analysis of the clinical features and genetic aberrations.

  8. "Twin language": a risk factor for language impairment?

    PubMed

    Bishop, D V; Bishop, S J

    1998-02-01

    Retrospective parental report of earlier "twin language" was obtained for two groups of twins. Sample G consisted of 94 twin pairs between the ages of 7 and 13 years recruited through the school system as a general population sample. Sample L consisted of 82 twin pairs between the ages of 7 and 13 years who had been recruited for a genetic study; of these twin pairs at least one of the twins had a speech-language impairment persisting to school age. Parental report of twin language was higher (around 50%) for children with speech-language impairment than for those with normal language (11%). Consistent with this, children with twin language obtained significantly lower mean language scores than other children, although their mean nonverbal IQ was equivalent. The exceptions were a handful of children whose parents described use of a "private language" that coexisted alongside normal use of English. These findings are consistent with the view that what is described as twin language is usually use of immature or deviant language by two children at the same developmental level.

  9. Temperament and Character in the Child and Adolescent Twin Study in Sweden (CATSS): Comparison to the General Population, and Genetic Structure Analysis

    PubMed Central

    Garcia, Danilo; Lundström, Sebastian; Brändström, Sven; Råstam, Maria; Cloninger, C. Robert; Kerekes, Nóra; Nilsson, Thomas; Anckarsäter, Henrik

    2013-01-01

    Background The Child and Adolescent Twin Study in Sweden (CATSS) is an on-going, large population-based longitudinal twin study. We aimed (1) to investigate the reliability of two different versions (125-items and 238-items) of Cloninger's Temperament and Character Inventory (TCI) used in the CATSS and the validity of extracting the short version from the long version, (2) to compare these personality dimensions between twins and adolescents from the general population, and (3) to investigate the genetic structure of Cloninger's model. Method Reliability and correlation analyses were conducted for both TCI versions, 2,714 CATSS-twins were compared to 631 adolescents from the general population, and the genetic structure was investigated through univariate genetic analyses, using a model-fitting approach with structural equation-modeling techniques based on same-sex twin pairs from the CATSS (423 monozygotic and 408 dizygotic pairs). Results The TCI scores from the short and long versions showed comparable reliability coefficients and were strongly correlated. Twins scored about half a standard deviation higher in the character scales. Three of the four temperament dimensions (Novelty Seeking, Harm Avoidance, and Persistence) had strong genetic and non-shared environmental effects, while Reward Dependence and the three character dimensions had moderate genetic effects, and both shared and non-shared environmental effects. Conclusions Twins showed higher scores in character dimensions compared to adolescents from the general population. At least among adolescents there is a shared environmental influence for all of the character dimensions, but only for one of the temperament dimensions (i.e., Reward Dependence). This specific finding regarding the existence of shared environmental factors behind the character dimensions in adolescence, together with earlier findings showing a small shared environmental effects on character among young adults and no shared

  10. Variations in the Binary Conception Model in Twinning.

    ERIC Educational Resources Information Center

    Lord, Thomas R.

    1988-01-01

    Presents a brief summary of the transformation of a single fertilized ovum into a multi-celled human. Discusses the similarities and differences of identical and non-identical twins. Cites twin pairs that do not neatly fit the monozygotic or dizygotic schemes of human development. (RT)

  11. Monoamniotic monochorionic twins discordant for noncompaction cardiomyopathy.

    PubMed

    Ng, Dianna; Bouhlal, Yosr; Ursell, Philip C; Shieh, Joseph T C

    2013-06-01

    Occasionally "identical twins" are phenotypically different, raising the question of zygosity and the issue of genetic versus environmental influences during development. We recently noted monochorionic-monoamniotic twins, one of which had an isolated cardiac abnormality, noncompaction cardiomyopathy, a condition characterized by cardiac ventricular hypertrabeculation. We examined the prenatal course and subsequent pathologic correlation since ventricular morphogenesis may depend on early muscular contraction and blood flow. The monochorionic-monoamniotic female twin pair was initially identified since one fetus presented with increased nuchal translucency. Complete heart block was later identified in the fetus with nuchal translucency who did not survive after delivery. In contrast, the unaffected twin had normal cardiac studies both prenatally and postnatally. Pathologic analysis of the affected twin demonstrated noncompaction of the left ventricle with dysplasia of the aortic and pulmonary valves. Dissection of the cardiac conduction system disclosed atrioventricular bundle fibrosis. Maternal lupus studies, amniocentesis with karyotype, and studies for 22q11.2 were normal. To test for zygosity, we performed multiple STR marker analysis and found that all markers were shared even using nonblood tissues from the affected twin. These studies demonstrate that monozygotic twins that are monochorionic monoamniotic can be discordant for cardiac noncompaction. The results suggest further investigation into the potential roles of pathologic fibrosis, contractility, and blood flow in cardiac ventricle development. PMID:23636980

  12. Thai Twin Registry: description of the initial stage.

    PubMed

    Nanakorn, Somsong; Chusilp, Kusuma; Kutanan, Wibhu

    2013-02-01

    The present study describes the initial phase of the Thai Twin Registry (TTR) in Khon Kaen University, a pioneer research university located in the Northeast of Thailand. The initial steps of the study included the analysis of dermatoglyphic information in Thai twins for answering the research question: Are monozygotic (MZ) and dizygotic (DZ) twins different in dermatoglyphic variables? Subjects were 212 twin pairs (131 MZ and 81 [corrected] DZ), consisting of 155 males and 269 females. Four types of fingerprint pattern (FP) - that is, arch, radial loop, ulnar loop, and whorl - were classified and analyzed and compared between MZ and DZ twins. The arch radial loop and whorl frequencies differ between MZ and DZ twins. When comparing FP in each finger, only the right little finger shows a statistically different FP, while the FP similarity average from 10 homologous fingers of co-twins was greater in MZ than DZ twins. By using the Area Under the Receiver Operating Characteristic curve analysis, the MZ twins could be differentiated from DZ twins by the FP similarity. Summarizing, this valuable report about TTR was conducted by analysis of FP data, which indicated that the MZ and DZ twins exhibited FP pattern and FP similarity differences. Other dermatoglyphic studies of the existing FP database, such as finger ridge count, finger ridge density, and minutia, will be considered for ongoing research at the TTR.

  13. T-cell-replete haploidentical transplantation versus autologous stem cell transplantation in adult acute leukemia: a matched pair analysis.

    PubMed

    Gorin, Norbert-Claude; Labopin, Myriam; Piemontese, Simona; Arcese, William; Santarone, Stella; Huang, He; Meloni, Giovanna; Ferrara, Felicetto; Beelen, Dietrich; Sanz, Miguel; Bacigalupo, Andrea; Ciceri, Fabio; Mailhol, Audrey; Nagler, Arnon; Mohty, Mohamad

    2015-04-01

    Adult patients with acute leukemia in need of a transplant but without a genoidentical donor are usually considered upfront for transplantation with stem cells from any other allogeneic source, rather than autologous stem cell transplantation. We used data from the European Society for Blood and Marrow Transplantation and performed a matched pair analysis on 188 T-cell-replete haploidentical and 356 autologous transplants done from January 2007 to December 2012, using age, diagnosis, disease status, cytogenetics, and interval from diagnosis to transplant as matching factors. "Haploidentical expert" centers were defined as having reported more than five haploidentical transplants for acute leukemia (median value for the study period). The median follow-up was 28 months. Multivariate analyses, including type of transplant categorized into three classes ("haploidentical regular", "haploidentical expert" and autologous), conditioning intensity (reduced intensity versus myeloablative conditioning) and the random effect taking into account associations related to matching, showed that non-relapse mortality was higher following haploidentical transplants in expert (HR: 4.7; P=0.00004) and regular (HR: 8.98; P<10(-5)) centers. Relapse incidence for haploidentical transplants was lower in expert centers (HR:0.39; P=0.0003) but in regular centers was similar to that for autologous transplants. Leukemia-free survival and overall survival rates were higher following autologous transplantation than haploidentical transplants in regular centers (HR: 1.63; P=0.008 and HR: 2.31; P=0.0002 respectively) but similar to those following haploidentical transplants in expert centers. We conclude that autologous stem cell transplantation should presently be considered as a possible alternative to haploidentical transplantation in regular centers that have not developed a specific expert program. PMID:25637051

  14. T-cell-replete haploidentical transplantation versus autologous stem cell transplantation in adult acute leukemia: a matched pair analysis.

    PubMed

    Gorin, Norbert-Claude; Labopin, Myriam; Piemontese, Simona; Arcese, William; Santarone, Stella; Huang, He; Meloni, Giovanna; Ferrara, Felicetto; Beelen, Dietrich; Sanz, Miguel; Bacigalupo, Andrea; Ciceri, Fabio; Mailhol, Audrey; Nagler, Arnon; Mohty, Mohamad

    2015-04-01

    Adult patients with acute leukemia in need of a transplant but without a genoidentical donor are usually considered upfront for transplantation with stem cells from any other allogeneic source, rather than autologous stem cell transplantation. We used data from the European Society for Blood and Marrow Transplantation and performed a matched pair analysis on 188 T-cell-replete haploidentical and 356 autologous transplants done from January 2007 to December 2012, using age, diagnosis, disease status, cytogenetics, and interval from diagnosis to transplant as matching factors. "Haploidentical expert" centers were defined as having reported more than five haploidentical transplants for acute leukemia (median value for the study period). The median follow-up was 28 months. Multivariate analyses, including type of transplant categorized into three classes ("haploidentical regular", "haploidentical expert" and autologous), conditioning intensity (reduced intensity versus myeloablative conditioning) and the random effect taking into account associations related to matching, showed that non-relapse mortality was higher following haploidentical transplants in expert (HR: 4.7; P=0.00004) and regular (HR: 8.98; P<10(-5)) centers. Relapse incidence for haploidentical transplants was lower in expert centers (HR:0.39; P=0.0003) but in regular centers was similar to that for autologous transplants. Leukemia-free survival and overall survival rates were higher following autologous transplantation than haploidentical transplants in regular centers (HR: 1.63; P=0.008 and HR: 2.31; P=0.0002 respectively) but similar to those following haploidentical transplants in expert centers. We conclude that autologous stem cell transplantation should presently be considered as a possible alternative to haploidentical transplantation in regular centers that have not developed a specific expert program.

  15. A Study of the Conjoint Drawings of Identical and Fraternal Twins: A Pilot Study.

    ERIC Educational Resources Information Center

    Rehmann, Jacqueline T.

    Drawings designed by three identical and three fraternal, normal, 6- and 7-year-old twin pairs are inspected for signs of a struggle for individual identity. Each twin must go through the process of becoming aware of him/herself as separate from the mother and must individuate from his/her twin as well. Interdependence may retard maturation. In…

  16. A Monozygotic Twin Difference Study of Friends' Aggression and Children's Adjustment Problems

    ERIC Educational Resources Information Center

    Vitaro, Frank; Brendgen, Mara; Boivin, Michel; Cantin, Stephane; Dionne, Ginette; Tremblay, Richard E.; Girard, Alain; Perusse, Daniel

    2011-01-01

    This study used the monozygotic (MZ) twin difference method to examine whether differences in friends' aggression increased the differences in MZ twins' aggression and depressive symptoms from kindergarten to Grade 1 and whether perceived victimization by the friend played a mediating role in this context. Participants were 223 MZ twin pairs.…

  17. Bidirectional Influences between Maternal Parenting and Children's Peer Problems: A Longitudinal Monozygotic Twin Difference Study

    ERIC Educational Resources Information Center

    Yamagata, Shinji; Takahashi, Yusuke; Ozaki, Koken; Fujisawa, Keiko K.; Nonaka, Koichi; Ando, Juko

    2013-01-01

    This twin study examined the bidirectional relationship between maternal parenting behaviors and children's peer problems that were not confounded by genetic and family environmental factors. Mothers of 259 monozygotic twin pairs reported parenting behaviors and peer problems when twins were 42 and 48 months. Path analyses on monozygotic twin…

  18. I. 'Street of twins': multiple births in Cuba II. The Cuban twin registry: an update / twin research reports: cord entanglement; heritability of clubfoot; school separation / twins and twin researchers in the news: reunited at seventy-eight; basketball duo dissolved; delivered holding hands; the better brew; award winners.

    PubMed

    Segal, Nancy L; Marcheco-Teruel, Beatriz

    2014-08-01

    I was part of a people-to-people tour of Havana, Cuba during the first week in April 2014. Among the many highlights of that adventure were an informal meeting with Dr Beatriz Marcheco-Teruel, from Cuba's National Center for Medical Genetics, and a visit to the famous 'Street of Twins'. A fortuitous meeting with parents of twins in the fishing town of Jaimanitas was also an extraordinary event. The Cuban experience is followed by summaries of recent twin research, covering umbilical cord entanglement, the heritability of clubfoot and school separation policies for twins. Media reports include twins reunited at age 78, the future of UCLA's twin basketball players, MZ twins born holding hands, a twin conflict over beer and a pair of American Psychological Association honors for Drs Nancy L. Segal and Thomas J. Bouchard, Jr. PMID:24992183

  19. I. 'Street of twins': multiple births in Cuba II. The Cuban twin registry: an update / twin research reports: cord entanglement; heritability of clubfoot; school separation / twins and twin researchers in the news: reunited at seventy-eight; basketball duo dissolved; delivered holding hands; the better brew; award winners.

    PubMed

    Segal, Nancy L; Marcheco-Teruel, Beatriz

    2014-08-01

    I was part of a people-to-people tour of Havana, Cuba during the first week in April 2014. Among the many highlights of that adventure were an informal meeting with Dr Beatriz Marcheco-Teruel, from Cuba's National Center for Medical Genetics, and a visit to the famous 'Street of Twins'. A fortuitous meeting with parents of twins in the fishing town of Jaimanitas was also an extraordinary event. The Cuban experience is followed by summaries of recent twin research, covering umbilical cord entanglement, the heritability of clubfoot and school separation policies for twins. Media reports include twins reunited at age 78, the future of UCLA's twin basketball players, MZ twins born holding hands, a twin conflict over beer and a pair of American Psychological Association honors for Drs Nancy L. Segal and Thomas J. Bouchard, Jr.

  20. A Twin Study of Personality and Temperament during Middle Childhood.

    ERIC Educational Resources Information Center

    Matheny, Adam P., Jr.; Dolan, Anne Brown

    1980-01-01

    In a study of 105 twin pairs, correlations for identical pairs were significantly higher than fraternal pairs on all but one factor: tough-mindedness. Data suggested several components and the total organization of those components of personality and temperament are genetically influenced. (Author)

  1. Evolutionary trajectories of hyperdiploid ALL in monozygotic twins.

    PubMed

    Bateman, C M; Alpar, D; Ford, A M; Colman, S M; Wren, D; Morgan, M; Kearney, L; Greaves, M

    2015-01-01

    Identical twins have provided unique insights on timing or sequence of genetic events in acute lymphoblastic leukaemia (ALL). To date, this has mainly focused on ALL with MLL or ETV6-RUNX1 fusions, with hyperdiploid ALL remaining less well characterised. We examined three pairs of monozygotic twins, two concordant and one discordant for hyperdiploid ALL, for single-nucleotide polymorphism (SNP)-defined copy number alterations (CNAs), IGH/L plus TCR gene rearrangements and mutations in NRAS, KRAS, FLT3 and PTPN11 genes. We performed whole exome sequencing in one concordant twin pair. Potential 'driver' CNAs were low, 0-3 per case, and all were different within a pair. One patient had an NRAS mutation that was lacking from leukaemic cells of the twin sibling. By exome sequencing, there were 12 nonsynonymous mutations found in one twin and 5 in the other, one of which in SCL44A2 was shared or identical. Concordant pairs had some identical IGH/L and TCR rearrangements. In the twin pair with discordant hyperdiploid ALL, the healthy co-twin had persistent low level hyperdiploid CD19+ cells that lacked a CNA present in the ALL cells of her sibling. From these data, we propose that hyperdiploid ALL arises in a pre-B cell in utero and mutational changes necessary for clinical ALL accumulate subclonally and postnatally. PMID:24897505

  2. A core gut microbiome in obese and lean twins.

    PubMed

    Turnbaugh, Peter J; Hamady, Micah; Yatsunenko, Tanya; Cantarel, Brandi L; Duncan, Alexis; Ley, Ruth E; Sogin, Mitchell L; Jones, William J; Roe, Bruce A; Affourtit, Jason P; Egholm, Michael; Henrissat, Bernard; Heath, Andrew C; Knight, Rob; Gordon, Jeffrey I

    2009-01-22

    The human distal gut harbours a vast ensemble of microbes (the microbiota) that provide important metabolic capabilities, including the ability to extract energy from otherwise indigestible dietary polysaccharides. Studies of a few unrelated, healthy adults have revealed substantial diversity in their gut communities, as measured by sequencing 16S rRNA genes, yet how this diversity relates to function and to the rest of the genes in the collective genomes of the microbiota (the gut microbiome) remains obscure. Studies of lean and obese mice suggest that the gut microbiota affects energy balance by influencing the efficiency of calorie harvest from the diet, and how this harvested energy is used and stored. Here we characterize the faecal microbial communities of adult female monozygotic and dizygotic twin pairs concordant for leanness or obesity, and their mothers, to address how host genotype, environmental exposure and host adiposity influence the gut microbiome. Analysis of 154 individuals yielded 9,920 near full-length and 1,937,461 partial bacterial 16S rRNA sequences, plus 2.14 gigabases from their microbiomes. The results reveal that the human gut microbiome is shared among family members, but that each person's gut microbial community varies in the specific bacterial lineages present, with a comparable degree of co-variation between adult monozygotic and dizygotic twin pairs. However, there was a wide array of shared microbial genes among sampled individuals, comprising an extensive, identifiable 'core microbiome' at the gene, rather than at the organismal lineage, level. Obesity is associated with phylum-level changes in the microbiota, reduced bacterial diversity and altered representation of bacterial genes and metabolic pathways. These results demonstrate that a diversity of organismal assemblages can nonetheless yield a core microbiome at a functional level, and that deviations from this core are associated with different physiological states (obese

  3. An Update on the Florida State Twin Registry

    PubMed Central

    Taylor, Jeanette E.; Hart, Sara A.; Mikolajewski, Amy J.

    2012-01-01

    The Florida State Twin Registry began in 2002 through a pilot study of personality disorders and executive cognitive functioning in adult twins. Since 2006, the registry has grown substantially as part of the Learning Disability Research Center at Florida State University that recently began its second funding cycle through the National Institute of Child Health and Development. An update on the Florida State Twin Registry sample, focus, and measures is provided as well as future directions. PMID:23067863

  4. X-chromosome inactivation is mostly random in placental tissues of female monozygotic twins and triplets

    SciTech Connect

    Bamforth, F.; Machin, G.; Innes, M.

    1996-01-22

    Patterns of X-chromosome inactivation in chorion, amnion, and cord from 79 pairs of twins were examined. Seven sets of triplets were included in the analysis, both as twin pairs and triplets. Twins were stratified as dizygotic (DZ), monozygotic (MZ), monochorionic, and dichorionic and were selected for birth weight discordance, discordance for congenital anomalies, twin-twin transfusion syndrome, and various patterns of vascular anastomosis. X-inactivation was predominantly symmetric. Chorion was the most likely tissue to show asymmetric X-inactivation and was found most frequently in MZ dichorionic twins. There was no correlation of X-inactivation pattern with the selected clinical criteria. This study does not confirm that asymmetric X-inactivation in embryonic tissues is a common phenomenon in female twins, including monozygotic twins. 27 refs., 2 figs., 9 tabs.

  5. Methylation matters? Decreased methylation status of genomic DNA in the blood of schizophrenic twins.

    PubMed

    Bönsch, Dominikus; Wunschel, Michael; Lenz, Bernd; Janssen, Gesa; Weisbrod, Matthias; Sauer, Heinrich

    2012-08-15

    Studies of schizophrenia inheritance in identical twins show a concordance of about 50%, which supports an epigenetic model. In our present study we investigated methylation of genomic DNA and promoter methylation of Reelin and SOX10 genes in peripheral blood of twins suffering from schizophrenia. Global DNA methylation was reduced (52.3%) in schizophrenic twins if compared with healthy control twins (65.7%). The reduced methylation was significant in males only. We also found a similar hypomethylation in the non-affected twins of discordant pairs and a mixed group of psychiatric controls. In discordant twins there was a relative hypermethylation of the SOX10 promoter. Within-pair-difference of methylation of Reelin promoter was significantly lower in monozygotic twins than in dizygotic twins. PMID:23102571

  6. Genetic and epigenetic analysis of monozygotic twins discordant for testicular cancer.

    PubMed

    Kratz, Christian P; Edelman, Daniel C; Wang, Yonghong; Meltzer, Paul S; Greene, Mark H

    2014-01-01

    Despite the notion that monozygotic (identical) twins share 100% identical genetic information, genetic differences among monozygotic twin pairs do occur and can be explained by mechanisms occurring during post-zygotic events. Despite such twins being fundamentally "identical", these post-zygotic genetic changes may give rise to phenotypic differences and genetic diseases. Consequently, studies of monozygotic twin pairs discordant for specific genetic diseases represent an important tool for the identification of disease genes. We used array comparative genomic hybridization (aCGH) and methylation arrays to search for genetic and epigenetic differences in blood drawn from four monozygotic twin pairs discordant for testicular germ cell tumors. No consistent differences were identified. A larger twin study would be required to achieve confident discovery of very subtle differences between monozygotic twins discordant for testicular germ cell tumors. PMID:25379132

  7. Neuropathologic assessment of dementia markers in identical and fraternal twins.

    PubMed

    Iacono, Diego; Volkman, Inga; Nennesmo, Inger; Pedersen, Nancy L; Fratiglioni, Laura; Johansson, Boo; Karlsson, David; Winblad, Bengt; Gatz, Margaret

    2014-07-01

    Twin studies are an incomparable source of investigation to shed light on genetic and non-genetic components of neurodegenerative diseases, as Alzheimer's disease (AD). Detailed clinicopathologic correlations using twin longitudinal data and post-mortem examinations are mostly missing. We describe clinical and pathologic findings of seven monozygotic (MZ) and dizygotic (DZ) twin pairs. Our findings show good agreement between clinical and pathologic diagnoses in the majority of the twin pairs, with greater neuropathologic concordance in MZ than DZ twins. Greater neuropathologic concordance was found for β-amyloid than tau pathology within the pairs. ApoE4 was associated with higher β-amyloid and earlier dementia onset, and importantly, higher frequency of other co-occurring brain pathologies, regardless of the zygosity. Dementia onset, dementia duration, difference between twins in age at dementia onset and at death, did not correlate with AD pathology. These clinicopathologic correlations of older identical and fraternal twins support the relevance of genetic factors in AD, but not their sufficiency to determine the pathology, and consequently the disease, even in monozygotic twins. It is the interaction among genetic and non-genetic risks which plays a major role in influencing, or probably determining, the degeneration of those brain circuits associated with pathology and cognitive deficits in AD. PMID:24450926

  8. Symmetry relations of magnetic twin laws.

    PubMed

    Schlessman, J; Litvin, D B

    2001-11-01

    Symmetry relationships between two simultaneously observed domain states (domain pair) are used to determine physical properties that can distinguish between the observed domains. Here the tabulation of these symmetry relationships is extended from non-magnetic cases to magnetic cases, in terms of magnetic point groups, i.e. all possible magnetic symmetry groups and magnetic twinning groups of domain pairs are determined and tabulated. PMID:11679705

  9. Creativity in Monozygotic and Dyzygotic Twins.

    ERIC Educational Resources Information Center

    Richmond, Bert O.

    The purpose of this study is to clarify further the relationships among creative, cognitive, and affective production of students. Thirteen pairs of twins, eight monozygotic (MZ), five dyzygotic (DZ), were administered the Torrance Tests of Creative Thinking, MMPI, and Revised Beta Examination. The F ratio for testing significance of within-set…

  10. Genetic and environmental contributions to population group differences on the Raven's Progressive Matrices estimated from twins reared together and apart.

    PubMed

    Rushton, J Philippe; Bons, Trudy Ann; Vernon, Philip A; Cvorović, Jelena

    2007-07-22

    We carried out two studies to test the hypothesis that genetic and environmental influences explain population group differences in general mental ability just as they do individual differences within a group. We estimated the heritability and environmentality of scores on the diagrammatic puzzles of the Raven's Coloured and/or Standard Progressive Matrices (CPM/SPM) from two independent twin samples and correlated these estimates with group differences on the same items. In Study 1, 199 pairs of 5- to 7-year-old monozygotic (MZ) and dizygotic (DZ) twins reared together provided estimates of heritability and environmentality for 36 puzzles from the CPM. These estimates correlated with the differences between the twins and 94 Serbian Roma (both rs=0.32; Ns=36; ps<0.05). In Study 2, 152 pairs of adult MZ and DZ twins reared apart provided estimates of heritability and environmentality for 58 puzzles from the SPM. These estimates correlated with the differences among 11 diverse samples including (i) the reared-apart twins, (ii) another sample of Serbian Roma, and (iii) East Asian, White, South Asian, Coloured and Black high school and university students in South Africa. In 55 comparisons, group differences were more pronounced on the more heritable and on the more environmental items (mean rs=0.40 and 0.47, respectively; Ns=58; ps<0.05). After controlling for measurement reliability and variance in item pass rates, the heritabilities still correlated with the group differences, although the environmentalities did not. Puzzles found relatively difficult (or easy) by the twins were those found relatively difficult (or easy) by the others (mean r=0.87). These results suggest that population group differences are part of the normal variation expected within a universal human cognition. PMID:17504738

  11. Comparisons of dermatoglyphic patterns in monochorionic and dichorionic monozygotic twins.

    PubMed Central

    Reed, T; Uchida, I A; Norton, J A; Christian, J C

    1978-01-01

    The data presented here indicate that different influences affect dermatoglyphic pattern development in MC-MZ and DC-MZ twins. Only five of 84 variables had significant mean differences but their clustering suggested a real difference in mean placement of the atd angle. Nineteen of 84 variables had significantly different within-pair mean squares for the two twin types. Larger numbers of twins will be required to obtain accurate estimates of the magnitude of the dermatoglyphic differences between MC-MZ and DC-MZ twins. Studies of dermatoglyphics in MC-MZ and DC-MZ twins are important to the understanding of factors which influence early embryonic development and when better documented may provide a mechanism for retrospectively diagnosing placental type of MZ twins. PMID:568879

  12. Merohedral twins revisited: quinary twins and beyond.

    PubMed

    Quiquandon, Marianne; Gratias, Denis; Sirindil, Abdullah; Portier, Richard

    2016-01-01

    A twin is defined as being an external operation between two identical crystals that share a fraction of the atomic structure with no discontinuity from one crystal to the other. This includes merohedral twins, twins by reticular merohedry as well as coherent twins by contact where only the habit plane is shared by the two adjacent crystals (epitaxy). Interesting and original cases appear when the invariant substructure is built with positions belonging to the same {\\bb Z}-module as, for example, the quinary twin structure first drawn by Albrecht Dürer [(1525). The Painter's Manual: a Manual of Measurement of Lines, Areas and Solids by Means of Compass and Ruler. Facsimile Edition (1977), translated with commentary by W. L. Strauss. New York: Abaris Books]. This paper will show that the Dürer twins, once defined in five-dimensional space, are simple merohedral twins, in the sense of Georges Friedel, leaving the five-dimensional lattice invariant. This analysis will be generalized to some other higher-order {\\bb Z}-modules. PMID:26697867

  13. Merohedral twins revisited: quinary twins and beyond

    PubMed Central

    Quiquandon, Marianne; Gratias, Denis; Sirindil, Abdullah; Portier, Richard

    2016-01-01

    A twin is defined as being an external operation between two identical crystals that share a fraction of the atomic structure with no discontinuity from one crystal to the other. This includes merohedral twins, twins by reticular merohedry as well as coherent twins by contact where only the habit plane is shared by the two adjacent crystals (epitaxy). Interesting and original cases appear when the invariant substructure is built with positions belonging to the same -module as, for example, the quinary twin structure first drawn by Albrecht Dürer [(1525 ▸). The Painter’s Manual: a Manual of Measurement of Lines, Areas and Solids by Means of Compass and Ruler. Facsimile Edition (1977), translated with commentary by W. L. Strauss. New York: Abaris Books]. This paper will show that the Dürer twins, once defined in five-dimensional space, are simple merohedral twins, in the sense of Georges Friedel, leaving the five-dimensional lattice invariant. This analysis will be generalized to some other higher-order -modules. PMID:26697867

  14. Pan-genome of the dominant human gut-associated archaeon, Methanobrevibacter smithii, studied in twins

    PubMed Central

    Hansen, Elizabeth E.; Lozupone, Catherine A.; Rey, Federico E.; Guruge, Janaki L.; Narra, Aneesha; Goodfellow, Jonathan; Zaneveld, Jesse R.; McDonald, Daniel T.; Goodrich, Julia A.; Heath, Andrew C.; Knight, Rob; Gordon, Jeffrey I.

    2011-01-01

    The human gut microbiota harbors three main groups of H2-consuming microbes: methanogens including the dominant archaeon, Methanobrevibacter smithii, a polyphyletic group of acetogens, and sulfate-reducing bacteria. Defining their roles in the gut is important for understanding how hydrogen metabolism affects the efficiency of fermentation of dietary components. We quantified methanogens in fecal samples from 40 healthy adult female monozygotic (MZ) and 28 dizygotic (DZ) twin pairs, analyzed bacterial 16S rRNA datasets generated from their fecal samples to identify taxa that co-occur with methanogens, sequenced the genomes of 20 M. smithii strains isolated from families of MZ and DZ twins, and performed RNA-Seq of a subset of strains to identify their responses to varied formate concentrations. The concordance rate for methanogen carriage was significantly higher for MZ versus DZ twin pairs. Co-occurrence analysis revealed 22 bacterial species-level taxa positively correlated with methanogens: all but two were members of the Clostridiales, with several being, or related to, known hydrogen-producing and -consuming bacteria. The M. smithii pan-genome contains 987 genes conserved in all strains, and 1,860 variably represented genes. Strains from MZ and DZ twin pairs had a similar degree of shared genes and SNPs, and were significantly more similar than strains isolated from mothers or members of other families. The 101 adhesin-like proteins (ALPs) in the pan-genome (45 ± 6 per strain) exhibit strain-specific differences in expression and responsiveness to formate. We hypothesize that M. smithii strains use their different repertoires of ALPs to create diversity in their metabolic niches, by allowing them to establish syntrophic relationships with bacterial partners with differing metabolic capabilities and patterns of co-occurrence. PMID:21317366

  15. Asymmetric twin Dark Matter

    SciTech Connect

    Farina, Marco

    2015-11-09

    We study a natural implementation of Asymmetric Dark Matter in Twin Higgs models. The mirroring of the Standard Model strong sector suggests that a twin baryon with mass around 5 GeV is a natural Dark Matter candidate once a twin baryon number asymmetry comparable to the SM asymmetry is generated. We explore twin baryon Dark Matter in two different scenarios, one with minimal content in the twin sector and one with a complete copy of the SM, including a light twin photon. The essential requirements for successful thermal history are presented, and in doing so we address some of the cosmological issues common to many Twin Higgs models. The required interactions we introduce predict signatures at direct detection experiments and at the LHC.

  16. Asymmetric twin Dark Matter

    SciTech Connect

    Farina, Marco

    2015-11-01

    We study a natural implementation of Asymmetric Dark Matter in Twin Higgs models. The mirroring of the Standard Model strong sector suggests that a twin baryon with mass around 5 GeV is a natural Dark Matter candidate once a twin baryon number asymmetry comparable to the SM asymmetry is generated. We explore twin baryon Dark Matter in two different scenarios, one with minimal content in the twin sector and one with a complete copy of the SM, including a light twin photon. The essential requirements for successful thermal history are presented, and in doing so we address some of the cosmological issues common to many Twin Higgs models. The required interactions we introduce predict signatures at direct detection experiments and at the LHC.

  17. Further possible physiological connectedness between identical twins: the London study.

    PubMed

    Parker, Adrian; Jensen, Christian

    2013-01-01

    Four pairs of monozygotic twins were tested for synchronous responses that occurred in the physiological data of one twin during the period when the other twin was exposed to shock and surprise stimuli. Each of the five stimuli was presented in random order, producing five blocks of trial periods within each 25-minute session per twin. There were eight possible trial periods within each block. The choice of the trial periods, that is, the exact time placement of the shock stimuli within the blocks, was determined randomly. Data from six sessions with the four pairs of twins were used by the same polygraph expert who was successful in a previous study in identifying these trial periods. In accordance with the previously determined protocol for the experiment, six of these trials were passed on, leaving 24 trial blocks for which assessments were made as to which period the stimulus had occurred. Six of these gave hits, whereas three hits were expected by chance and four of these six correct placements were made by one of the pairs of twins. The data provide further justification for a major study in this area using the outlined methodology with selected pairs of twins. PMID:23294817

  18. Relations between twins' similarity of appearance and behavioral similarity: testing an assumption.

    PubMed

    Matheny, A P; Wilson, R S; Dolan, A B

    1976-07-01

    Questionnaires rating twins' physical similarity and similarity of dress were obtained from the parents of 121 identical and 70 same-sex fraternal twin pairs. Within-pair difference scores on several behavioral measures (two intelligence tests, two perceptual tests, one reading test, one test of speech articulation, and one personality inventory) were correlated with the twins' scores for physical similarity and similarity of dress. The correlations revealed no systematic relation between the similarity of appearance and the similarity of behaviors for either the identical twin pairs or the same-sex fraternal twin pairs. The assumption that twins' behaviors are more alike because they are more similar in appearance does not seem warranted.

  19. Traces of embryogenesis are the same in monozygotic and dizygotic twins: not compatible with double ovulation

    PubMed Central

    Boklage, Charles E.

    2009-01-01

    Common knowledge of over a century has it that monozygotic and dizygotic twinning events occur by unrelated mechanisms: monozygotic twinning ‘splits’ embryos, producing anomalously re-arranged embryogenic asymmetries; dizygotic twinning begins with independent ovulations yielding undisturbed parallel embryogeneses with no expectation of departures from singleton outcomes. The anomalies statistically associated with twin births are due to the re-arranged embryos of the monozygotics. Common knowledge further requires that dizygotic pairs are dichorionic; monochorionicity is exclusive to monozygotic pairs. These are fundamental certainties in the literature of twin biology. Multiple observations contradict those common knowledge understandings. The double ovulation hypothesis of dizygotic twinning is untenable. Girl–boy twins differ subtly from all other humans of either sex, absolutely not representative of all dizygotics. Embryogenesis of dizygotic twins differs from singleton development at least as much as monozygotic embryogenesis does, and in the same ways, and the differences between singletons and twins of both zygosities represent a coherent system of re-arranged embryogenic asymmetries. Dizygotic twinning and monozygotic twinning have the same list of consequences of anomalous embryogenesis. Those include an unignorable fraction of dizygotic pairs that are in fact monochorionic, plus many more sharing co-twins’ cells in tissues other than a common chorion. The idea that monozygotic and dizygotic twinning events arise from the same embryogenic mechanism is the only plausible hypothesis that might explain all of the observations. PMID:19252194

  20. Genetic and environmental influences on optimism and its relationship to mental and self-rated health: a study of aging twins.

    PubMed

    Mosing, Miriam A; Zietsch, Brendan P; Shekar, Sri N; Wright, Margaret J; Martin, Nicholas G

    2009-11-01

    Optimism has been shown to be important in maintaining wellbeing into old age, but little is known about the sources of variation in optimism and its links to mental and somatic health. Optimism, mental, and self-rated health were measured in 3,053 twin individuals (501 MZF, 153 MZM, 274 DZF, 77 DZM, and 242 DZ opposite-sex twin pairs and 561 single twins) over 50 years using the life orientation test, the General Health Questionnaire and a single-item question for self-rated health. Additive genetic factors explained 36, 34, and 46% of the variation in optimism, mental, and self-rated health, respectively, with the remainder being due to non-shared environmental influences. Genetic influences accounted for most of the covariance between the variables (14-20% of the genetic variance) indicating that in older adults genes predisposing to high optimism also predispose to good mental health and self-rated health.

  1. DNA methylation analysis of multiple tissues from newborn twins reveals both genetic and intrauterine components to variation in the human neonatal epigenome.

    PubMed

    Ollikainen, Miina; Smith, Katherine R; Joo, Eric Ji-Hoon; Ng, Hong Kiat; Andronikos, Roberta; Novakovic, Boris; Abdul Aziz, Nur Khairunnisa; Carlin, John B; Morley, Ruth; Saffery, Richard; Craig, Jeffrey M

    2010-11-01

    Mounting evidence from both animal and human studies suggests that the epigenome is in constant drift over the life course in response to stochastic and environmental factors. In humans, this has been highlighted by a small number of studies that have demonstrated discordant DNA methylation patterns in adolescent or adult monozygotic (MZ) twin pairs. However, to date, it remains unclear when such differences emerge, and how prevalent they are across different tissues. To address this, we examined the methylation of four differentially methylated regions associated with the IGF2/H19 locus in multiple birth tissues derived from 91 twin pairs: 56 MZ and 35 dizygotic (DZ). Tissues included cord blood-derived mononuclear cells and granulocytes, human umbilical vein endothelial cells, buccal epithelial cells and placental tissue. Considerable variation in DNA methylation was observed between tissues and between unrelated individuals. Most interestingly, methylation discordance was also present within twin pairs, with DZ pairs showing greater discordance than MZ pairs. These data highlight the variable contribution of both intrauterine environmental exposures and underlying genetic factors to the establishment of the neonatal epigenome of different tissues and confirm the intrauterine period as a sensitive time for the establishment of epigenetic variability in humans. This has implications for the effects of maternal environment on the development of the newborn epigenome and supports an epigenetic mechanism for the previously described phenomenon of 'fetal programming' of disease risk. PMID:20699328

  2. Social Development in Six-Year-Old Identical and Fraternal Twins.

    ERIC Educational Resources Information Center

    Schave, Barbara; And Others

    Four null hypotheses were formulated to test for relationships between pairs of identical and fraternal twins and their parents on measures of locus of control. Two additional hypotheses were formulated to test for differences between mean scores of identical and fraternal twins and scores of their parents on these same constructs. Twenty pairs of…

  3. Genetic Influences on Reading Difficulties in Boys and Girls: The Colorado Twin Study

    ERIC Educational Resources Information Center

    Hawke, Jesse L.; Wadsworth, Sally J.; DeFries, John C.

    2006-01-01

    To test the hypothesis that the genetic etiology for reading disability may differ in males and females, data from identical and fraternal twin pairs were analysed using both concordance and multiple regression methods. The sample included 264 identical (129 male, 135 female) and 214 same-sex fraternal (121 male, 93 female) twin pairs in which at…

  4. Twin-to-twin transfusion syndrome

    MedlinePlus

    ... skin, too much blood, and a higher blood pressure. The twin that gets too much blood may develop cardiac failure because of the high blood volume. The infant may also need medicine to strengthen ...

  5. Current twin studies in Germany: report on CoSMoS, SOEP, and ChronoS.

    PubMed

    Hahn, Elisabeth; Gottschling, Juliana; Spinath, Frank M

    2013-02-01

    This article summarizes the status of three recent German twin studies: CoSMoS, SOEP, and ChronoS. The German twin study on Cognitive Ability, Self-Reported Motivation, and School Achievement (CoSMoS) is a three-wave longitudinal study of monozygotic and dizygotic twins reared together, and aims to investigate predictors of and influences on school performance. In the first wave of the data collection in 2005, 408 pairs of twins aged between 7 and 11 as well as their parents participated in CoSMoS. The SOEP twin study is an extended twin study, which has combined data from monozygotic and dizygotic twins reared together with additional data from full sibling pairs, mother-child, and grandparent-child dyads who participated in the German Socio-Economic Panel (GSOEP) study. The SOEP twin project comprises about 350 twin and 950 non-twin pairs aged between 17 and 70. Data were collected between 2009 and 2010, with a focus on personality traits, wellbeing, education, employment, income, living situation, life-satisfaction, and several attitudes. The aim of the Chronotype twin study (ChronoS) was to examine genetic and environmental influences on chronotype (morningness and eveningness), coping strategies, and several aspects of the previous SOEP twin project in a sample of 301 twin pairs aged between 19 and 76 years, recruited in 2010 and 2011. Part of the ChronoS twin sample also participated in the earlier SOEP twin study, representing a second wave of assessments. We briefly describe the design and contents of these three studies as well as selected recent findings.

  6. A Twin Protection Effect? Explaining Twin Survival Advantages with a Two-Process Mortality Model

    PubMed Central

    2016-01-01

    Twin studies that focus on the correlation in age-at-death between twin pairs have yielded important insights into the heritability and role of genetic factors in determining lifespan, but less attention is paid to the biological and social role of zygosity itself in determining survival across the entire life course. Using data from the Danish Twin Registry and the Human Mortality Database, we show that monozygotic twins have greater cumulative survival proportions at nearly every age compared to dizygotic twins and the Danish general population. We examine this survival advantage by fitting these data with a two-process mortality model that partitions survivorship patterns into extrinsic and intrinsic mortality processes roughly corresponding to acute, environmental and chronic, biological origins. We find intrinsic processes confer a survival advantage at older ages for males, while at younger ages, all monozygotic twins show a health protection effect against extrinsic death akin to a marriage protection effect. While existing research suggests an increasingly important role for genetic factors at very advanced ages, we conclude that the social closeness of monozygotic twins is a plausible driver of the survival advantage at ages <65. PMID:27192433

  7. Genetic modelling of dizygotic twinning in pedigrees of spontaneous dizygotic twins

    SciTech Connect

    Meulemans, W.J.; Derom, C.A.; Derom, R.M.

    1996-01-22

    The inheritance of spontaneous dizygotic (DZ) twinning was investigated in 1,422 three-generation pedigrees ascertained through mothers of spontaneous DZ proband twins. DZ twinning was modelled as a trait expressed only in women. The penetrance was modelled first as a parity independent and secondly as parity dependent. The observed frequencies of maternal and paternal grandmothers with DZ twins differed significantly from the expectations under an X-linked mode of inheritance. Complex segregation analysis showed that the parity-independent phenotype of {open_quotes}having DZ twins{close_quotes} was consistent with an autosomal monogenic dominant model, with a gene frequency of 0.035 and a female-specific lifetime penetrance of 0.10. Recessive, polygenic, and sporadic models were rejected. The autosomal dominant model revealed a strong robustness against a changing population prevalence and the loss of information due to the presence of same-sexed twin pairs of unknown zygosity. When DZ twinning was modelled as a parity dependent trait, the data were compatible with an autosomal dominant model with a gene frequency of 0.306 and a penetrance of 0.03 per birth for female gene carriers. 19 refs., 5 tabs.

  8. A Twin Protection Effect? Explaining Twin Survival Advantages with a Two-Process Mortality Model.

    PubMed

    Sharrow, David J; Anderson, James J

    2016-01-01

    Twin studies that focus on the correlation in age-at-death between twin pairs have yielded important insights into the heritability and role of genetic factors in determining lifespan, but less attention is paid to the biological and social role of zygosity itself in determining survival across the entire life course. Using data from the Danish Twin Registry and the Human Mortality Database, we show that monozygotic twins have greater cumulative survival proportions at nearly every age compared to dizygotic twins and the Danish general population. We examine this survival advantage by fitting these data with a two-process mortality model that partitions survivorship patterns into extrinsic and intrinsic mortality processes roughly corresponding to acute, environmental and chronic, biological origins. We find intrinsic processes confer a survival advantage at older ages for males, while at younger ages, all monozygotic twins show a health protection effect against extrinsic death akin to a marriage protection effect. While existing research suggests an increasingly important role for genetic factors at very advanced ages, we conclude that the social closeness of monozygotic twins is a plausible driver of the survival advantage at ages <65.

  9. The Twin Jet Nebula

    NASA Technical Reports Server (NTRS)

    1997-01-01

    M2-9 is a striking example of a 'butterfly' or a bipolar planetary nebula. Another more revealing name might be the 'Twin Jet Nebula.' If the nebula is sliced across the star, each side of it appears much like a pair of exhausts from jet engines. Indeed, because of the nebula's shape and the measured velocity of the gas, in excess of 200 miles per second, astronomers believe that the description as a super-super-sonic jet exhaust is quite apt. This is much the same process that takes place in a jet engine: The burning and expanding gases are deflected by the engine walls through a nozzle to form long, collimated jets of hot air at high speeds. M2-9 is 2,100 light-years away in the constellation Ophiucus. The observation was taken Aug. 2, 1997 by the Hubble telescope's Wide Field and Planetary Camera 2. In this image, neutral oxygen is shown in red, once-ionized nitrogen in green, and twice-ionized oxygen in blue.

  10. Sex ratios provide evidence for monozygotic twinning in the ring-tailed lemur, Lemur catta.

    PubMed

    St Clair, John; Campbell-Palmer, Roisin; Lathe, Richard

    2014-02-01

    Monozygotic (MZ) twinning is generally considered to be rare in species other than human. We inspected sex ratios in European zoo-bred ring-tailed lemurs (Lemur catta), revealing a significant excess of same-sex twins. Of 94 pairs, 60 (64%) were either both males or both females (p = .004). Application of the Weinberg differential rule argues that 27% of all twins in this species are MZ pairs. In this protected species, where twinning is commonplace (~50% of newborns are twins), the probable existence of frequent MZ twinning has ramifications for breeding programs aimed to maximize genetic diversity, and suggests that twin studies in a species other than human could have potential as a medical research tool.

  11. Sex ratios provide evidence for monozygotic twinning in the ring-tailed lemur, Lemur catta.

    PubMed

    St Clair, John; Campbell-Palmer, Roisin; Lathe, Richard

    2014-02-01

    Monozygotic (MZ) twinning is generally considered to be rare in species other than human. We inspected sex ratios in European zoo-bred ring-tailed lemurs (Lemur catta), revealing a significant excess of same-sex twins. Of 94 pairs, 60 (64%) were either both males or both females (p = .004). Application of the Weinberg differential rule argues that 27% of all twins in this species are MZ pairs. In this protected species, where twinning is commonplace (~50% of newborns are twins), the probable existence of frequent MZ twinning has ramifications for breeding programs aimed to maximize genetic diversity, and suggests that twin studies in a species other than human could have potential as a medical research tool. PMID:24384029

  12. Cohort Profile: The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry)

    PubMed Central

    Gatz, Margaret; Harris, Jennifer R; Kaprio, Jaakko; McGue, Matt; Smith, Nicholas L; Snieder, Harold; Spiro, Avron; Butler, David A

    2015-01-01

    The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry) is a comprehensive registry of White male twin pairs born in the USA between 1917 and 1927, both of the twins having served in the military. The purpose was medical research and ultimately improved clinical care. The cohort was assembled in the early 1960s with identification of approximately 16 000 twin pairs, review of service records, a brief mailed questionnaire assessing zygosity, and a health survey largely comparable to questionnaires used at that time with Scandinavian twin registries. Subsequent large-scale data collection occurred in 1974, 1985 and 1998, repeating the health survey and including information on education, employment history and earnings. Self-reported data have been supplemented with mortality, disability and medical data through record linkage. Potential collaborators should access the study website [http://www.iom.edu/Activities/Veterans/TwinsStudy.aspx] or e-mail the Medical Follow-up Agency at [Twins@nas.edu]. Questionnaire data are being prepared for future archiving with the National Archive of Computerized Data on Aging (NACDA) at the Inter-University Consortium for Political and Social Research (ICPSR), University of Michigan, MI. PMID:25183748

  13. Cohort Profile: The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry).

    PubMed

    Gatz, Margaret; Harris, Jennifer R; Kaprio, Jaakko; McGue, Matt; Smith, Nicholas L; Snieder, Harold; Spiro, Avron; Butler, David A

    2015-06-01

    The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry) is a comprehensive registry of White male twin pairs born in the USA between 1917 and 1927, both of the twins having served in the military. The purpose was medical research and ultimately improved clinical care. The cohort was assembled in the early 1960s with identification of approximately 16,000 twin pairs, review of service records, a brief mailed questionnaire assessing zygosity, and a health survey largely comparable to questionnaires used at that time with Scandinavian twin registries. Subsequent large-scale data collection occurred in 1974, 1985 and 1998, repeating the health survey and including information on education, employment history and earnings. Self-reported data have been supplemented with mortality, disability and medical data through record linkage. Potential collaborators should access the study website [http://www.iom.edu/Activities/Veterans/TwinsStudy.aspx] or e-mail the Medical Follow-up Agency at [Twins@nas.edu]. Questionnaire data are being prepared for future archiving with the National Archive of Computerized Data on Aging (NACDA) at the Inter-University Consortium for Political and Social Research (ICPSR), University of Michigan, MI. PMID:25183748

  14. Danish cohort of monozygotic inflammatory bowel disease twins: Clinical characteristics and inflammatory activity

    PubMed Central

    Moller, Frederik Trier; Knudsen, Lina; Harbord, Marcus; Satsangi, Jack; Gordon, Hannah; Christiansen, Lene; Christensen, Kaare; Jess, Tine; Andersen, Vibeke

    2016-01-01

    AIM: To describe the establishment of a Danish inflammatory bowel diseases (IBD) twin cohort with focus on concordance of treatment and inflammatory markers. METHODS: We identified MZ twins, likely to be discordant or concordant for IBD, by merging information from the Danish Twin Register and the National Patient Register. The twins were asked to provide biological samples, questionnaires, and data access to patient files and public registries. Biological samples were collected via a mobile laboratory, which allowed for immediate centrifugation, fractionation, and storage of samples. The mean time from collection of samples to storage in the -80 °C mobile freezer was less than one hour. The diagnoses where validated using the Copenhagen diagnostic criteria. RESULTS: We identified 159 MZ IBD twin pairs, in a total of 62 (39%) pairs both twins agreed to participate. Of the supposed 62 IBD pairs, the IBD diagnosis could be confirmed in 54 pairs. The cohort included 10 concordant pairs, whereof some were discordant for either treatment or surgery. The 10 concordant pairs, where both pairs suffered from IBD, included eight CD/CD pairs, one UC/UC pair and one UC/IBDU pair. The discordant pairs comprised 31 UC, 5 IBDU (IBD unclassified), and 8 CD discordant pairs. In the co-twins not affected by IBD, calprotectin was above 100 μg/g in 2 participants, and above 50 μg/g in a further 5 participants. CONCLUSION: The presented IBD twin cohorts are an excellent resource for bioinformatics studies with proper adjustment for disease-associated exposures including medication and inflammatory activity in the co-twins. PMID:27275097

  15. Power estimation for gene-longevity association analysis using concordant twins.

    PubMed

    Tan, Qihua; Zhao, Jing Hua; Kruse, Torben; Christensen, Kaare

    2014-01-01

    Statistical power is one of the major concerns in genetic association studies. Related individuals such as twins are valuable samples for genetic studies because of their genetic relatedness. Phenotype similarity in twin pairs provides evidence of genetic control over the phenotype variation in a population. The genetic association study on human longevity, a complex trait that is under control of both genetic and environmental factors, has been confronted by the small sample sizes of longevity subjects which limit statistical power. Twin pairs concordant for longevity have increased probability for carrying beneficial genes and thus are useful samples for gene-longevity association analysis. We conducted a computer simulation to estimate the power of association study using longevity concordant twin pairs. We observed remarkable power increases in using singletons from longevity concordant twin pairs as cases in comparison with cases of sporadic proband. A similar power would require doubled sample sizes for fraternal twins than for identical twins who are concordant for longevity suggesting that longevity concordant identical twins are more efficient samples than fraternal twins. We also observed an approximate of 2- to 3-fold increase in sample sizes needed for longevity cutoff at age 90 as compared with that at age 95. Overall, our results showed high value of twins in genetic association studies on human longevity. PMID:25309757

  16. Adolescent health and adult labor market outcomes.

    PubMed

    Lundborg, Petter; Nilsson, Anton; Rooth, Dan-Olof

    2014-09-01

    Whereas a large literature has shown the importance of early life health for adult socioeconomic outcomes, there is little evidence on the importance of adolescent health. We contribute to the literature by studying the impact of adolescent health status on adult labor market outcomes using a unique and large-scale dataset covering almost the entire population of Swedish males. We show that most types of major conditions have long-run effects on future outcomes, and that the strongest effects result from mental conditions. Including sibling fixed effects or twin pair fixed effects reduces the magnitudes of the estimates, but they remain substantial.

  17. Dementia in Swedish Twins: Predicting Incident Cases

    PubMed Central

    Reynolds, Chandra A.; Finkel, Deborah; Pedersen, Nancy L.; Walters, Ellen

    2010-01-01

    Thirty same-sex twin pairs were identified in which both members were assessed at baseline and one twin subsequently developed dementia, at least 3 years subsequent to the baseline measurement, while the partner remained cognitively intact for at least three additional years. Eighteen of the 30 cases were diagnosed with Alzheimer’s disease. Baseline assessments, conducted when twins’ average age was 70.6 (SD = 6.8), included a mailed questionnaire and in-person testing. Which twin would develop dementia was predicted by less favorable lipid values (higher apoB, ratio of apoB to apoA1, and total cholesterol), poorer grip strength, and—to a lesser extent—higher emotionality on the EAS Temperament Scale. Given the long preclinical period that characterizes Alzheimer’s disease, these findings may suggest late life risk factors for dementia, or may reflect changes that are part of preclinical disease. PMID:20972885

  18. TWSVR: Regression via Twin Support Vector Machine.

    PubMed

    Khemchandani, Reshma; Goyal, Keshav; Chandra, Suresh

    2016-02-01

    Taking motivation from Twin Support Vector Machine (TWSVM) formulation, Peng (2010) attempted to propose Twin Support Vector Regression (TSVR) where the regressor is obtained via solving a pair of quadratic programming problems (QPPs). In this paper we argue that TSVR formulation is not in the true spirit of TWSVM. Further, taking motivation from Bi and Bennett (2003), we propose an alternative approach to find a formulation for Twin Support Vector Regression (TWSVR) which is in the true spirit of TWSVM. We show that our proposed TWSVR can be derived from TWSVM for an appropriately constructed classification problem. To check the efficacy of our proposed TWSVR we compare its performance with TSVR and classical Support Vector Regression(SVR) on various regression datasets.

  19. Upgrades for TwinSol facility

    NASA Astrophysics Data System (ADS)

    O'Malley, P. D.; Bardayan, D. W.; Kolata, J. J.; Hall, M. R.; Hall, O.; Allen, J.; Becchetti, F. D.

    2016-06-01

    TwinSol, a pair of coupled, superconducting solenoids, was one of the first devices capable of producing beams of radioactive nuclei at energies near the Coulomb barrier. A primary beam from University of Notre Dame (UND) tandem accelerator is used to bombard a primary target producing a secondary beam in flight. TwinSol is used to gather, separate, and focus the recoils. Since it was commissioned at the UND in 1997, at least 58 publications have reported data from its use and there have been hundreds of collaborators from many different countries that use this device. Currently, plans are in place at the UND to provide several upgrades to TwinSol, including a multi-cell gas production target and the possible addition of a third solenoid. Upgrades currently in progress will be discussed along with future plans.

  20. TWSVR: Regression via Twin Support Vector Machine.

    PubMed

    Khemchandani, Reshma; Goyal, Keshav; Chandra, Suresh

    2016-02-01

    Taking motivation from Twin Support Vector Machine (TWSVM) formulation, Peng (2010) attempted to propose Twin Support Vector Regression (TSVR) where the regressor is obtained via solving a pair of quadratic programming problems (QPPs). In this paper we argue that TSVR formulation is not in the true spirit of TWSVM. Further, taking motivation from Bi and Bennett (2003), we propose an alternative approach to find a formulation for Twin Support Vector Regression (TWSVR) which is in the true spirit of TWSVM. We show that our proposed TWSVR can be derived from TWSVM for an appropriately constructed classification problem. To check the efficacy of our proposed TWSVR we compare its performance with TSVR and classical Support Vector Regression(SVR) on various regression datasets. PMID:26624223

  1. NOTE: Arterio-venous flow between monochorionic twins determined during intra-uterine transfusion

    NASA Astrophysics Data System (ADS)

    van Gemert, Martin J. C.; van den Wijngaard, Jeroen P. H. M.; Lopriore, Enrico; Pasman, Suzanne A.; Vandenbussche, Frank P. H. A.

    2008-04-01

    Twin-twin transfusion syndrome (TTTS) is a severe complication of monozygotic (identical) twin fetuses sharing one single (monochorionic) placenta. TTTS is caused by a net inter-twin transfusion of blood through placental anastomoses, from one twin (the donor) to the other (the recipient), which link the two feto-placental circulations. Currently, the only reliable method to measure the net inter-twin transfusion clinically is when incomplete laser therapy of TTTS occurs and one of the twins becomes anemic and requires an intra-uterine transfusion of adult red blood cells. Then, differences between adult hemoglobin concentrations measured during the transfusion and at birth relate not only to the net inter-twin transfusion but also to the finite lifetime of the adult red blood cells. We have analyzed this situation, derived the differential equations of adult hemoglobin in the donor and recipient twins, given the solutions and given expressions relating the net inter-twin flow with clinically measured parameters. We have included single and multiple intra-uterine transfusions. In conclusion, because incomplete laser therapy occurs frequently, and some cases require an intra-uterine transfusion, this method may allow collecting a wealth of net inter-twin flow data from clinicians involved in laser therapy of TTTS. To aid to the widespread use of this method, we have presented the equations as clearly as possible in tables for easy use by others.

  2. Attention Problems and Attention-Deficit/Hyperactivity Disorder in Discordant and Concordant Monozygotic Twins: Evidence of Environmental Mediators

    ERIC Educational Resources Information Center

    Lehn, Hanne; Derks, Eske M.; Hudziak, James J.; Heutink, Peter; van Beijsterveldt, Toos; Boomsma, Dorret I.

    2007-01-01

    Objective: To study familial and nonfamilial environmental influences on attention problems and attention-deficit/hyperactivity disorder (ADHD) in monozygotic twins discordant and concordant-high and low for these traits. Method: Ninety-five twin pairs from The Netherlands Twin Register were selected. Longitudinal survey data were collected at 1,…

  3. Peer Network Overlap in Twin, Sibling, and Friend Dyads

    ERIC Educational Resources Information Center

    McGuire, Shirley; Segal, Nancy L.

    2013-01-01

    Research suggests that sibling–peer connections are important for understanding adolescent problem behaviors. Using a novel behavioral genetic design, the current study investigated peer network overlap in 300 child–child pairs (aged 7-13 years) in 5 dyad types: monozygotic (MZ), dizygotic twins, full siblings (FSs), friend pairs, and virtual…

  4. Epigenetic discordance at imprinting control regions in twins.

    PubMed

    Ollikainen, Miina; Craig, Jeffrey M

    2011-06-01

    Imprinting control regions are differentially methylated in a parent-of-origin-dependent manner and this methylation state is inherited through the germline. These regions control parent-specific monoallelic expression of their target genes. Genetically identical organisms show considerable variation in their epigenomes owing to environmental and stochastic influences creating fluctuations in phenotype. Monozygotic twin pairs discordant for imprinting disorders due to epigenetic changes at imprinting control regions are an example of phenotypic variation caused by extreme variations of the epigenome. Here, we discuss the within-pair epigenetic discordance at imprinted loci, both in phenotypically concordant and discordant monozygotic twin pairs. PMID:22122339

  5. Heritability of responses to painful stimuli in women: a classical twin study.

    PubMed

    Norbury, Timothy A; MacGregor, Alex J; Urwin, Jane; Spector, Tim D; McMahon, Stephen B

    2007-11-01

    There is as yet no conclusive evidence for the heritability of pain sensitivity in humans. We performed a classical twin study to evaluate the relative contributions of genetic and environmental factors on responses to painful stimuli in women. Ninety-eight pairs of twins, 51 monozygotic (MZ) and 47 dizygotic (DZ), were recruited from the TwinsUK adult registry held at St Thomas' Hospital, London. The correlation of quantitative sensory testing scores for the different responses to painful stimuli were compared between the MZ and DZ twin pairs and structural equation modelling was used to provide an estimate of the heritability. Statistically significant genetic components (varying between 22 and 55%) were seen for the responses to the majority of painful stimuli including: heat pain threshold (HPT), the pain rating during induction of a thermal burn, the secondary areas of punctate hyperalgesia and brush evoked allodynia following the induction of a 45 degrees C thermal burn, and the pain ratings during the iontophoresis of adenosine triphosphate (ATP) and acid. The area of skin flare following thermal burn induction did not have a significant genetic component; rather common environmental factors provided the greatest contribution (65%). In our experiment neither shared genetic nor environmental features were significant in determining the extent of thermal sensitisation. In summary we show that sensitivity to a variety of experimental thermal, mechanical and chemical pain-producing stimuli has a genetic contribution. Our study demonstrates the importance of genetic factors in determining human experimental pain sensitivity, and opens the way for its use as a phenotype in gene discovery. Since experimental pain sensitivity is known to be a predictor for pathological pain, our data imply that genetic factors have an important aetiological contribution towards clinical pain states. PMID:17932101

  6. Guidelines on Library Twinning.

    ERIC Educational Resources Information Center

    Doyle, Robert P., Comp.; Scarry, Patricia, Comp.

    This document serves as an overview of the many forms of library twinning, or formal exchanges of materials and/or staff between two institutions. Twinning can be reciprocal, but often involves a one-way arrangement whereby a library in a developing country receives a visit from a librarian of a developed country. Either way, both institutions can…

  7. Birth weight, infant mortality, and race: twin comparisons and genetic/environmental inputs.

    PubMed

    Conley, Dalton; Strully, Kate W

    2012-12-01

    Genetic and environmental inputs may shape population health disparities in varying ways. In this article, we use unique variation involved in twin births to attempt to untangle how genetic and prenatal environmental variation may make different contributions to infant health among white and black populations in the United States. Using twin fixed effects models and data from the 1995-1997 Matched Multiple Birth Dataset we compare birth weight-mortality associations across twin sex composition, zygosity, and race. Findings reveal suggestive differences between fraternal and imputed identical twin estimates for white and black twin pairs. PMID:23083893

  8. LETTER TO THE EDITOR: Arterio-venous flow between monochorionic twins determined during intra-uterine transfusion. Nonlinear decay of adult red blood cells

    NASA Astrophysics Data System (ADS)

    van Gemert, Martin J. C.; Pasman, Suzanne A.; van den Wijngaard, Jeroen P. H. M.; Lopriore, Enrico; Vandenbussche, Frank P. H. A.

    2008-07-01

    Recently, we derived equations relating the flow of adult red blood cells through a placental arterio-venous anastomosis with intra-uterine and post-natal measured adult hemoglobin concentrations. In this letter, we re-derived the equations, now including a more realistic nonlinear decay of adult red blood cells, and re-evaluated the measurement accuracy of the arterio-venous flow and the lifetime of the red blood cells.

  9. The 'Planemo' Twins

    NASA Astrophysics Data System (ADS)

    2006-08-01

    The cast of exoplanets has an extraordinary new member. Using ESO's telescopes, astronomers have discovered an approximately seven-Jupiter-mass companion to an object that is itself only twice as hefty. Both objects have masses similar to those of extra-solar giant planets, but they are not in orbit around a star - instead they appear to circle each other. The existence of such a double system puts strong constraints on formation theories of free-floating planetary mass objects. ESO PR Photo 29a/06 ESO PR Photo 29a/06 Double System of Planetary Mass Objects (Artist's View) Ray Jayawardhana of the University of Toronto (Canada) and Valentin D. Ivanov of ESO report the discovery in the August 3 issue of Science Express, the rapid online publication service of the journal Science. "This is a truly remarkable pair of twins - each having only about one percent the mass of our Sun," said Jayawardhana. "Its mere existence is a surprise, and its origin and fate a bit of a mystery." Roughly half of all Sun-like stars come in pairs. So do about a sixth of brown dwarfs, 'failed stars' that have less than 75 Jupiter masses and are unable to sustain nuclear fusion in their cores. During the past five years, astronomers have identified a few dozen of even smaller free-floating planetary mass objects, or planemos, in nearby star forming regions. Oph 162225-240515, or Oph1622 for short, is the first planemo found to be a double. The researchers discovered the companion candidate in an optical image taken with ESO's 3.5-m New Technology Telescope at La Silla, Chile. They decided to take optical spectra and infrared images of the pair with ESO's 8.2-m Very Large Telescope to make sure that it is a true companion, instead of a foreground or background star that happens to be in the same line of sight. These follow up observations indeed confirmed that both objects are young, at the same distance, and much too cool to be stars. This suggests the two are physically associated. ESO PR

  10. The Epigenesis of Planum Temporale Asymmetry in Twins

    PubMed Central

    Eckert, Mark A.; Leonard, Christiana M.; Molloy, Elizabeth A.; Blumenthal, Jonathan; Zijdenbos, Alex; Giedd, Jay N.

    2009-01-01

    Variation in hemispheric asymmetry of the planum temporale (PT) has been related to verbal ability. The degree to which genetic and environmental factors mediate PT asymmetry is not known. This study examined the heritability for planar asymmetry in 12 dizygotic (DZ) and 27 monozygotic (MZ) male twin pairs who were between 6 and 16 years of age. There was weak but positive evidence for heritability of planar asymmetry. Co-twin similarity for planar asymmetry and Sylvian fissure morphology increased when excluding twins discordant for writing hand and when excluding twins exhibiting birth weight differences >20% from the analyses. Birth weight differences were also related to twin differences in total cerebral volume, but not central sulcus asymmetry. These results suggest that exogenous perinatal factors affect the epigenesis of planar asymmetry development. PMID:12050086

  11. Genome-Wide Identification of Epigenetic Hotspots Potentially Related to Cardiovascular Risk in Adult Women after a Complicated Pregnancy

    PubMed Central

    Oudejans, Cees; Poutsma, Ankie; Michel, Omar; Mulders, Joyce; Visser, Allerdien; van Dijk, Marie; Nauta, Tessa; Bokslag, Anouk; Paulus, Walter; de Haas, Andreas; Koolwijk, Pieter; de Groot, Christianne J. M.

    2016-01-01

    Background The physiological demands of pregnancy on the maternal cardiovascular system can catapult women into a metabolic syndrome that predisposes to atherosclerosis in later life. We sought to identify the nature of the epigenomic changes associated with the increased cardiovascular disease (CVD) risk in adult women following pre-eclampsia. Findings We assessed the genome wide epigenetic profile by methyl-C sequencing of monozygotic parous twin sister pairs discordant for a severe variant of pre-eclampsia. In the adult twin sisters at risk for CVD as a consequence of a complicated pregnancy, a set of 12 differentially methylated regions with at least 50% difference in methylation percentage and the same directional change was found to be shared between the affected twin sisters and significantly different compared to their unaffected monozygous sisters. Conclusion The current epigenetic marker set will permit targeted analysis of differentially methylated regions potentially related to CVD risk in large cohorts of adult women following complicated pregnancies. PMID:26870946

  12. Neonatal exposure to the D1 agonist SKF38393 inhibits pair bonding in the adult prairie vole.

    PubMed

    Hostetler, Caroline M; Harkey, Shanna L; Krzywosinski, Tarin B; Aragona, Brandon J; Bales, Karen L

    2011-10-01

    The monogamous prairie vole displays developmental sensitivity to early pharmacological manipulation in a number of species-typical social behaviors. The long-term consequences of altering the neonatal dopamine system are not well characterized. This study examined whether early manipulation of the dopamine system, a known mediator of adult prairie vole social behavior, during neonatal development would affect adult aggressive and attachment behaviors. Eight-day-old pups were given a single treatment with either 1 mg/kg of SKF38393 (D1 agonist), quinpirole (D2 agonist), SCH23390 (D1 antagonist), eticlopride (D2 antagonist), or saline vehicle. As adults, animals received tests for intrasexual aggression and partner preference. Activation of D1-like receptors in pups impaired partner preference formation, but had no effect on aggression. Other neonatal treatments had no effect on their behavior as adults. To determine whether D1 activation in pups induced changes in dopamine receptor expression, we performed autoradiography on striatal tissue from a second cohort of saline-treated and SKF38393-treated animals. Although sex differences were observed, we found no treatment differences in D1 or D2 receptor binding in any striatal subregion. This study shows that exposure to a single early pharmacological alteration of dopamine receptor activity may have long-term effects on the social behavior of prairie voles. PMID:21918384

  13. Late language emergence in 24 month twins: Heritable and increased risk for LLE in twins

    PubMed Central

    Rice, Mabel L.; Zubrick, Stephen R.; Taylor, Catherine L.; Gayán, Javier; Bontempo, Daniel E.

    2013-01-01

    Purpose This study investigated the etiology of Late Language Emergence (LLE) in 24-month-old twins considering possible twinning, zygosity, gender, and heritability effects for vocabulary and grammar phenotypes. Method A population-based sample of 473 twin pairs participated. Multilevel modelling estimated means and variances of vocabulary and grammar phenotypes, controlling for familiality. Heritability was estimated with DeFries-Fulker regression, and variance components models, to determine effects of heritability, shared-environment, and non-shared environment. Results Twins had lower average language scores than norms for singleborn children, with lower average performance for MZ than DZ twins, and lower for boys than girls, although gender and zygosity did not interact. Gender did not predict LLE. Significant heritability was detected for vocabulary (.26) and grammar phenotypes (.52/.43 for males/females) in the full sample, and in the sample selected for LLE (.42 and .44). LLE and the appearance of Word Combinations were also significantly heritable (.22-.23). Conclusion The findings revealed an increased likelihood of LLE in twin toddlers compared to singleborn children that is modulated by zygosity and gender differences. Heritability estimates are consistent with previous research for vocabulary and add further suggestion of heritable differences in early grammar acquisition. PMID:24167238

  14. The genetic basis for cognitive ability, memory, and depression symptomatology in middle-aged and elderly chinese twins.

    PubMed

    Xu, Chunsheng; Sun, Jianping; Ji, Fuling; Tian, Xiaocao; Duan, Haiping; Zhai, Yaoming; Wang, Shaojie; Pang, Zengchang; Zhang, Dongfeng; Zhao, Zhongtang; Li, Shuxia; Hjelmborg, Jacob V B; Christensen, Kaare; Tan, Qihua

    2015-02-01

    The genetic influences on aging-related phenotypes, including cognition and depression, have been well confirmed in the Western populations. We performed the first twin-based analysis on cognitive performance, memory and depression status in middle-aged and elderly Chinese twins, representing the world's largest and most rapidly aging population. The sample consisted of 384 twin pairs with a median age of 50 years. Cognitive function was measured using the Montreal Cognitive Assessment (MoCA) scale; memory was assessed using the revised Wechsler Adult Intelligence scale; depression symptomatology was evaluated by the self-reported 30-item Geriatric Depression (GDS-30)scale. Both univariate and multivariate twin models were fitted to the three phenotypes with full and nested models and compared to select the best fitting models. Univariate analysis showed moderate-to-high genetic influences with heritability 0.44 for cognition and 0.56 for memory. Multivariate analysis by the reduced Cholesky model estimated significant genetic (rG = 0.69) and unique environmental (rE = 0.25) correlation between cognitive ability and memory. The model also estimated weak but significant inverse genetic correlation for depression with cognition (-0.31) and memory (-0.28). No significant unique environmental correlation was found for depression with other two phenotypes. In conclusion, there can be a common genetic architecture for cognitive ability and memory that weakly correlates with depression symptomatology, but in the opposite direction.

  15. The genetic basis for cognitive ability, memory, and depression symptomatology in middle-aged and elderly chinese twins.

    PubMed

    Xu, Chunsheng; Sun, Jianping; Ji, Fuling; Tian, Xiaocao; Duan, Haiping; Zhai, Yaoming; Wang, Shaojie; Pang, Zengchang; Zhang, Dongfeng; Zhao, Zhongtang; Li, Shuxia; Hjelmborg, Jacob V B; Christensen, Kaare; Tan, Qihua

    2015-02-01

    The genetic influences on aging-related phenotypes, including cognition and depression, have been well confirmed in the Western populations. We performed the first twin-based analysis on cognitive performance, memory and depression status in middle-aged and elderly Chinese twins, representing the world's largest and most rapidly aging population. The sample consisted of 384 twin pairs with a median age of 50 years. Cognitive function was measured using the Montreal Cognitive Assessment (MoCA) scale; memory was assessed using the revised Wechsler Adult Intelligence scale; depression symptomatology was evaluated by the self-reported 30-item Geriatric Depression (GDS-30)scale. Both univariate and multivariate twin models were fitted to the three phenotypes with full and nested models and compared to select the best fitting models. Univariate analysis showed moderate-to-high genetic influences with heritability 0.44 for cognition and 0.56 for memory. Multivariate analysis by the reduced Cholesky model estimated significant genetic (rG = 0.69) and unique environmental (rE = 0.25) correlation between cognitive ability and memory. The model also estimated weak but significant inverse genetic correlation for depression with cognition (-0.31) and memory (-0.28). No significant unique environmental correlation was found for depression with other two phenotypes. In conclusion, there can be a common genetic architecture for cognitive ability and memory that weakly correlates with depression symptomatology, but in the opposite direction. PMID:25586092

  16. Discordance of Prenatal and Neonatal Brain Development in Twins

    PubMed Central

    Mukherjee, Niyati; Kang, Chaeryon; Wolfe, Honor M.; Hertzberg, Barbara S.; Smith, J. Keith; Lin, Weili; Gerig, Guido; Hamer, Robert M.; Gilmore, John H.

    2009-01-01

    Background Discordance of birth weight has been observed in twin pairs, though little is known about prenatal and early neonatal discordance of head and brain size, and the role that zygosity and chorionicity play in discordances of early brain development in twins. Aims To compare prenatal and neonatal discordances of head size in monozygotic –monochorionic (MZ-MC), monozygotic-dichorionic (MZ-DC), and same-sex dizygotic-dichorionic twin pairs (DZ). Study Design Subjects prospectively had ultrasounds at 22 and 32 weeks gestational age, and magnetic resonance imaging (MRI) of the brain MRI after birth. Subjects 88 twin pairs recruited from two university hospital prenatal diagnostic clinics; 22 MZ-MC, 17 MZ-DC, and 49 same sex DZ pairs. Outcome measures Discordance of head circumference (HC) and weight at 22 weeks, 32 weeks and birth, as well as intracranial volume (ICV) on neonatal MRI. Results There were no group differences in discordance of head circumference and weight on the 22 or 32 week ultrasounds, or at birth. MZ-MC twins tended to have numerically greater discordances of HC and weight. There was a significant group difference in ICV on neonatal MRI (ANOVA, p = 0.0143), with DZ twins having significantly greater discordance than MZ-MC (p = 0.028) or MZ-DC (p = 0.0131) twins. Conclusions This study indicates that zygosity and chorionicity do not contribute to significant discordances of head size in late prenatal development. DZ twins do have significantly greater discordances of ICV on neonatal MRI, suggesting a relatively greater genetic influence on brain growth in the first weeks after birth. PMID:18804925

  17. Motor development of autistic monozygotic twins: a case study.

    PubMed

    Geddes, D

    1977-08-01

    A pair of autistic monozygotic twins were assessed on relevant portions of the Geddes Psychomotor Inventory. Over-all motor development of the 3-yr., 6-mo. old twins was similar and considered a partial consequence of the same genotype and comparable environmental experiences from birth. The twins exhibited poor or unsuccessful performance on tasks requiring abilities in language, communication, and appropriate relationships to objects; superior performance on specific fine manual motor skills, walking balance board, and climbing; at-age performance on tasks which were considered measures of patterned gross movement, balance, postural maintenance, and spatial orientation; and few typical autistic motor characteristics.

  18. Insights on Solar Twins

    NASA Astrophysics Data System (ADS)

    Sousa Duarte, Tharcisyo Sa e.; Soares da Costa, Jefferson; Dias do Nascimento Júnior, José

    2015-08-01

    The question about how to define a real solar twin are still active. Cayrel de Strobe et al. (1981) defined a solar twin like a star having at the same time the physical parameters, Teff, gravity, bolometric magnitude, microturbulent velocity, and chemical composition. We presented the more extensive sample of solar twins known to date. From these targets we will study the behavior of the solar twins as a function of fundamentals stellar parameters, effective temperature, luminosity, age, convective envelope mass deepening (1 - M*/M⊙), lithium abundance and rotation period. We selected the solar twins from observations with the spectropolarimeters ESPaDOnS at CFHT and the Narval at TBL and also on literature. All objects have high resolution and high signal to noise. Analyze this sample of solar twins will help us to understand how these stars whether located around of the Sun's place. Our preliminary results show that the lithium abundance presents one clear correlation with stellar age. The (1 - M*/M⊙) values obtained through our method provided good agreement with the solar value. The rotation periods allow us to assess the solar twins as a function of gyrochronology.

  19. ? - ? Double twinning in magnesium

    NASA Astrophysics Data System (ADS)

    Jäger, Aleš; Ostapovets, Andriy; Molnár, Peter; Lejček, Pavel

    2011-08-01

    It is demonstrated that metalworking processes performed at different temperatures can lead to the ? - ? double twinning. This twinning mode has been observed during direct extrusion of the coarse-grained Mg-0.3at.%Al alloy at 433 K and analysed in detail on room-temperature rolled magnesium single crystal with the c-axis parallel to transverse direction and the a-axis parallel to rolling direction. The ? - ? double twins originated during initial stage of the formation on coarse-grained and single-crystalline structure.

  20. Wisconsin Twin Panel.

    PubMed

    Van Hulle, Carol A; Lemery, Kathryn S; Goldsmith, H Hill

    2002-10-01

    The Wisconsin Twin Panel was initiated in 1994 to serve a study of the development of childhood mood and behavioral disorders. Families who give birth to twins within the state of Wisconsin are recruited within 6 months of the birth. The panel currently supports three ongoing, longitudinal research projects. Research foci include studying epigenetic contributions to emotional, physical, cognitive, and motoric development of infant and toddler twins; physiological concomitants of childhood temperament; and early risk and resiliency factors related to child psychopathology. All three studies include videotaped observational assessments and biological measures. PMID:12537886

  1. Twin and sibling attachment in a nationally representative sample.

    PubMed

    Fraley, R Chris; Tancredy, Caroline M

    2012-03-01

    The objective of this research was to evaluate the hypothesis that twin relationships are attachments, using data from a nationally representative sample. The results indicated that twin siblings were more likely than nontwin siblings to be attached to their siblings. Moreover, analyses indicated that both attachment theoretical and inclusive fitness perspectives are necessary for explaining these findings. Namely, twins were more likely to be attached than nontwin siblings, as expected from an attachment perspective. But identical twins were more likely than fraternal twins to be attached to one another, as might be expected from an inclusive fitness perspective. Cross-sectional analyses indicated that older people are less likely than younger people to use their sibling as an attachment figure compared to younger people and that married adults are less likely to use their sibling as an attachment figure than nonmarried people. PMID:22357709

  2. Effect of auditory deafferentation on the synaptic connectivity of a pair of identified interneurons in adult field crickets.

    PubMed

    Brodfuehrer, P D; Hoy, R R

    1988-01-01

    In adult crickets, Teleogryllus oceanicus, unilateral auditory deafferentation causes the medial dendrites of an afferent-deprived, identified auditory interneuron (Int-1) in the prothoracic ganglion to sprout and form new functional connections in the contralateral auditory neuropil. The establishment of these new functional connections by the deafferented Int-1, however, does not appear to affect the physiological responses of Int-1's homolog on the intact side of the prothoracic ganglion which also innervates this auditory neuropil. Thus it appears that the sprouting dendrites of the deafferented Int-1 are not functionally competing with those of the intact Int-1 for synaptic connections in the remaining auditory neuropil following unilateral deafferentation in adult crickets. Moreover, we demonstrate that auditory function is restored to the afferent-deprived Int-1 within 4-6 days following deafferentation, when few branches of Int-1's medial dendrites can be seen to have sprouted. The strength of the physiological responses and extent of dendritic sprouting in the deafferented Int-1 progressively increase with time following deafferentation. By 28 days following deafferentation, most of the normal physiological responses of Int-1 to auditory stimuli have been restored in the deafferented Int-1, and the medial dendrites of the deafferented Int-1 have clearly sprouted and grown across into the contralateral auditory afferent field. The strength of the physiological responses of the deafferented Int-1 to auditory stimuli and extent of dendritic sprouting in the deafferented Int-1 are greater in crickets deafferented as juveniles than as adults. Thus, neuronal plasticity persists in Int-1 following sensory deprivation from the earliest juvenile stages through adulthood.

  3. Preparing for Twins

    MedlinePlus

    ... single baby. Feeding twins, whether by breast or bottle, also requires some special strategies, and the doctor ... fertilization may involve implanting more than one fertilized egg into the uterus, while using infertility drugs can ...

  4. Occurrence of artificial sweeteners in human liver and paired blood and urine samples from adults in Tianjin, China and their implications for human exposure.

    PubMed

    Zhang, Tao; Gan, Zhiwei; Gao, Chuanzi; Ma, Ling; Li, Yanxi; Li, Xiao; Sun, Hongwen

    2016-09-14

    In this study, acesulfame (ACE), saccharin (SAC) and cyclamate (CYC) were found in all paired urine and blood samples collected from healthy adults, with mean values of 4070, 918 and 628 ng mL(-1), respectively, in urine and 9.03, 20.4 and 0.72 ng mL(-1), respectively, in blood. SAC (mean: 84.4 ng g(-1)) and CYC (4.29 ng g(-1)) were detectable in all liver samples collected from liver cancer patients, while ACE was less frequently detected. Aspartame (ASP) was not found in any analyzed human sample, which can be explained by the fact that this chemical metabolized rapidly in the human body. Among all adults, significantly positive correlations between SAC and CYC levels were observed (p < 0.001), regardless of human matrices. Nevertheless, no significant correlations between concentrations of SAC (or CYC) and ACE were found in any of the human matrices. Our results suggest that human exposure to SAC and CYC is related, whereas ACE originates from a discrete source. Females (or young adults) were exposed to higher levels of SAC and CYC than males (or elderly). The mean renal clearance of SAC was 730 mL per day per kg in adults, which was significantly (p < 0.001) lower than those for CYC (10 800 mL per day per kg) and ACE (10 300 mL per day per kg). The average total daily intake of SAC and ACE was 9.27 and 33.8 μg per kg bw per day, respectively. PMID:27383923

  5. Occurrence of artificial sweeteners in human liver and paired blood and urine samples from adults in Tianjin, China and their implications for human exposure.

    PubMed

    Zhang, Tao; Gan, Zhiwei; Gao, Chuanzi; Ma, Ling; Li, Yanxi; Li, Xiao; Sun, Hongwen

    2016-09-14

    In this study, acesulfame (ACE), saccharin (SAC) and cyclamate (CYC) were found in all paired urine and blood samples collected from healthy adults, with mean values of 4070, 918 and 628 ng mL(-1), respectively, in urine and 9.03, 20.4 and 0.72 ng mL(-1), respectively, in blood. SAC (mean: 84.4 ng g(-1)) and CYC (4.29 ng g(-1)) were detectable in all liver samples collected from liver cancer patients, while ACE was less frequently detected. Aspartame (ASP) was not found in any analyzed human sample, which can be explained by the fact that this chemical metabolized rapidly in the human body. Among all adults, significantly positive correlations between SAC and CYC levels were observed (p < 0.001), regardless of human matrices. Nevertheless, no significant correlations between concentrations of SAC (or CYC) and ACE were found in any of the human matrices. Our results suggest that human exposure to SAC and CYC is related, whereas ACE originates from a discrete source. Females (or young adults) were exposed to higher levels of SAC and CYC than males (or elderly). The mean renal clearance of SAC was 730 mL per day per kg in adults, which was significantly (p < 0.001) lower than those for CYC (10 800 mL per day per kg) and ACE (10 300 mL per day per kg). The average total daily intake of SAC and ACE was 9.27 and 33.8 μg per kg bw per day, respectively.

  6. The Fetal Heart in Twin-to-Twin Transfusion Syndrome

    PubMed Central

    Van Mieghem, Tim; Lewi, Liesbeth; Gucciardo, Léonardo; DeKoninck, Philip; Van Schoubroeck, Dominique; Devlieger, Roland; Deprest, Jan

    2010-01-01

    Twin-to-twin transfusion syndrome is a severe complication occurring in 10% of monochorionic twin pregnancies. The disease is usually explained as due to an intrauterine imbalance in intertwin blood exchange, which leads to a volume depleted-donor twin and an overfilled recipient twin. The recipient has signs of cardiac dysfunction, which can be measured using echocardiography or blood and amniotic fluid derived biomarkers. Whereas cardiac dysfunction typically progresses in pregnancies treated with amniodrainage, it usually disappears within a few weeks after fetoscopic laser coagulation of the connecting intertwin anastomoses. Nevertheless, recipients remain at a increased risk of pulmonary stenosis. In this paper, we summarize the cardiac alterations in twin-to-twin transfusion syndrome, describe the changes seen after fetal therapy, list the newly proposed staging systems based on fetal cardiac function, and make recommendations about the use of fetal echocardiography in the evaluation and followup of pregnancies complicated by twin-to-twin transfusion syndrome. PMID:20811613

  7. Twinning behavior of polycrystalline alpha-uranium under quasi static compression

    NASA Astrophysics Data System (ADS)

    Zhou, Ping; Xiao, Dawu; Wang, Wenyuan; Sang, Ge; Zhao, Yawen; Zou, Dongli; He, Lifeng

    2016-09-01

    Deformation twins in cast uranium strained to 4.2% and 6.2% by quasi static compression were investigated using electron backscattered diffraction and transmission electron microscopy. Twin types of {130}, '{172}', {112} and '{176}' were observed in present experiment. All the operative twin variants in each twin type have the highest Schmid factor among the equivalent variants. Some {130} twins in cast uranium were inclined to disappear during subsequent loading through the re-twinning processes with Schmid factor values greater than 0.4. The '(-176)' variant was identified by indexing the electron diffraction pattern combining with the stereographic projection analysis. Twin pairs of '(-176)'-'(-17-2)' occurred in the adjacent grains were well matched with the geometric compatibility factor value of 0.933.

  8. The natural course of monochorionic and dichorionic twin pregnancies: a historical cohort.

    PubMed

    Hack, Karien E A; Derks, Jan B; de Visser, Veerle L; Elias, Sjoerd G; Visser, Gerard H A

    2006-06-01

    Current early diagnosis, surveillance and intervention options make it hard to determine the natural course of twin pregnancies, especially regarding spontaneous preterm delivery and perinatal mortality. We studied the natural course in monochorionic (MC) and dichorionic (DC) twin pregnancies in a historical cohort. Twin pregnancies were studied in a unique database of 651 twin pairs born in the period 1907 to 1938. We examined the effect of chorionicity on gestational age, birthweight, perinatal mortality, intertwin birthweight differences, the incidence of preeclampsia and maternal mortality. Perinatal mortality was 27.7% for MC and 15.8% for DC twins (p < .001). Gestational age and birthweight were stronger predictors of perinatal mortality than chorionicity. Perinatal outcome was poorer for the second twin, especially in DC twins. Delivery before 37 weeks of gestation occurred more often in MC twin pregnancies (48.8% compared to 33.3% in DC twin pregnancies). DC twins were on average 288 g (95% confidence interval 201-376) heavier than MC twins. Severe birthweight discordancy occurred equally in MC and DC twins (18.1%). However, if present, mortality was only increased in MC twins. The birthweight of girls was not affected by the presence of a male co-twin. In this historical cohort MC twin pregnancies had a higher perinatal mortality, caused by a high incidence of low birthweight mainly due to preterm delivery. Mortality did not differ in deliveries after 31 weeks of gestation, which is in contrast to recent data. Apparently, modern obstetrics is more effective in reducing mortality in DC twins.

  9. On the discriminability of the handwriting of twins.

    PubMed

    Srihari, Sargur; Huang, Chen; Srinivasan, Harish

    2008-03-01

    As handwriting is influenced by physiology, training, and other behavioral factors, a study of the handwriting of twins can shed light on the individuality of handwriting. This paper describes the methodology and results of such a study where handwriting samples of twins were compared by an automatic handwriting verification system. The results complement that of a previous study where a diverse population was used. The present study involves samples of 206 pairs of twins, where each sample consisted of a page of handwriting. The verification task was to determine whether two half-page documents (where the original samples were divided into upper and lower halves) were written by the same individual. For twins there were 1236 verification cases -- including 824 tests where the textual content of writing was different, and 412 tests where it was the same. An additional set of 1648 test cases were obtained from handwriting samples of nontwins (general population). To make the handwriting comparison, the system computed macro features (overall pictorial attributes), micro features (characteristics of individual letters), and style features (characteristics of whole-word shapes and letter pairs). Four testing scenarios were evaluated: twins and nontwins writing the same text and writing different texts. Results of the verification tests show that the handwriting of twins is less discriminable than that of nontwins: an overall error rate of 12.91% for twins and 3.7% for nontwins. Error rates with identical twins were higher than with fraternal twins. Error rates in all cases can be arbitrarily reduced by rejecting (not making a decision on) borderline cases. A level of confidence in the results obtained is given by the fact that system error rates are comparable to that of humans (lower than that of lay persons and higher than that of questioned document examiners [QDEs]).

  10. Use of alternative treatments by chronic fatigue syndrome discordant twins.

    PubMed

    Afari; Eisenberg; Herrell; Goldberg; Kleyman; Ashton; Buchwald

    2000-03-21

    Background: Patients with chronic fatigue syndrome (CFS) have been faced with difficulties in diagnosis and lack of effective treatments. Anecdotal evidence suggests that use of alternative treatments may be common in these patients. Our primary objective was to compare the prevalence and patterns of alternative medicine use among twins who met the Centers for Disease Control and Prevention (CDC) CFS criteria to that of their non-CFS co-twins. Secondary goals were to assess how often alternative medicine use was discussed with physicians and the perceived benefit of these therapies. Methods: Sixty-three twin pairs discordant for CFS completed a survey about their use of 22 alternative therapies. Matched pair odds ratios and 95% confidence intervals were used to examine differences in the use between CFS twins and their non-CFS co-twins. Results: 91% of twins with CFS and 71% of non-CFS twins had used at least 1 alternative treatment in their lifetime. Twins with CFS were more likely to use homeopathy, mega-vitamins, herbal therapies, biofeedback, relaxation/meditation, guided imagery, massage therapy, energy healing, religious healing by others, and self-help groups than their non-CFS counterparts. A large proportion of all twins found alternative therapies helpful; however, only 42% of those with CFS and 23% of those without CFS discussed their use of alternative medicine with a physician. Conclusions: Individuals with CFS frequently used alternative medical treatments yet rarely communicated this use to their medical doctor. Future research should ascertain the usefulness of alternative practices in the management of CFS.

  11. The Child and Adolescent Twin Study in Sweden (CATSS).

    PubMed

    Anckarsäter, Henrik; Lundström, Sebastian; Kollberg, Linnea; Kerekes, Nora; Palm, Camilla; Carlström, Eva; Långström, Niklas; Magnusson, Patrik K E; Halldner, Linda; Bölte, Sven; Gillberg, Christopher; Gumpert, Clara; Råstam, Maria; Lichtenstein, Paul

    2011-12-01

    The Child and Adolescent Twin Study in Sweden (CATSS) is an ongoing longitudinal twin study targeting all twins born in Sweden since July 1, 1992. Since 2004, parents of twins are interviewed regarding the children's somatic and mental health and social environment in connection with their 9th or 12th birthdays (CATSS-9/12). By January 2010, 8,610 parental interviews concerning 17,220 twins had been completed, with an overall response rate of 80%. At age 15 (CATSS-15) and 18 (CATSS-18), twins and parents complete questionnaires that, in addition to assessments of somatic and mental health, include measures of personality development and psychosocial adaptation. Twin pairs in CATSS-9/12 with one or both twins screening positive for autism spectrum disorders, attention deficit/hyperactivity disorder, tic disorders, developmental coordination disorder, learning disorders, oppositional defiant disorder, conduct disorder, obsessive-compulsive disorder, and/or eating problems have been followed with in-depth questionnaires on family, social environment and personality, and subsequently by clinical assessments at age 15 together with randomly selected population controls, including 195 clinically assessed twin pairs from the first 2 year cohorts (CATSS-15/DOGSS). This article describes the cohorts and study groups, data collection, and measures used. Prevalences, distributions, heritability estimates, ages at onset, and sex differences of mental health problems in the CATSS-9/12, that were analyzed and found to be overall comparable to those of other clinical and epidemiological studies. The CATSS study has the potential of answering important questions on the etiology of childhood mental health problems and their role in the development of later adjustment problems. PMID:22506305

  12. Enhancement of episodic memory in young and healthy adults: a paired-pulse TMS study on encoding and retrieval performance.

    PubMed

    Gagnon, Geneviève; Schneider, Cyril; Grondin, Simon; Blanchet, Sophie

    2011-01-20

    Transcranial magnetic stimulation (TMS) is a neurophysiological tool that can transiently influence brain excitability and improve cognitive performance. Facilitation effects induced by low frequency repetitive TMS on memory functions have been shown in a few studies in young and healthy participants [29] and in older individuals with memory complaints [40]. However, regions specifically involved in encoding and retrieval were not always systematically targeted. We thus aimed to facilitate episodic memory with online TMS systematically applied over the left or right dorsolateral prefrontal cortex (DLPFC) while participants were performing a recognition task. We applied online paired-pulse TMS (ppTMS) (15 ms inter-stimulus interval) either during encoding or retrieving of verbal or non-verbal material. Participants were 11 right-handed young individuals (21.33 ± 2.27 years old). Repeated measures ANOVA showed shorter reaction time when ppTMS are applied over the left DLPFC during encoding as compared to right homologous stimulation or to Sham condition. In contrast, ppTMS over the right DLPFC during retrieval was associated with shorter reaction times compared to left homologous stimulation. Overall, our data support for the first time that online ppTMS over the DLPFCs is capable of hastening memory processes in young and healthy individuals. PMID:21094215

  13. Specific complications of monochorionic twin pregnancies: twin-twin transfusion syndrome and twin reversed arterial perfusion sequence.

    PubMed

    Chalouhi, G E; Stirnemann, J J; Salomon, L J; Essaoui, M; Quibel, T; Ville, Y

    2010-12-01

    Monochorionic twins are subjected to specific complications which originate in either imbalance or abnormality of the single placenta serving two twins. This unequal placental sharing can cause complications including twin-twin transfusion syndrome (TTTS), twin anemia-polycythemia sequence (TAPS), selective intrauterine growth restriction or twin reversed arterial perfusion sequence (TRAP). Monochorionicity also makes the management of these specific complications as well as that of a severe malformation in one twin hazardous since the spontaneous death of one twin exposes the co-twin to a risk of exsanguination into the dead twin and its placenta. The latter is responsible for the death of the co-twin in up to 20% of the cases and in ischemic sequelae in about the same proportions in the survivors. Although the symptoms of all these complications are very different, the keystone of their management comes down to either surgical destruction of the inter-twin anastomoses on the chorionic plate when aiming at dual survival or selective and permanent occlusion of the cord of a severely affected twin aiming at protecting the normal co-twin. This can be best achieved by fetoscopic selective laser coagulation and bipolar forceps cord coagulation respectively. PMID:20855238

  14. Overcoming Clinical Inertia: A Randomized Clinical Trial of a Telehealth Remote Monitoring Intervention Using Paired Glucose Testing in Adults With Type 2 Diabetes

    PubMed Central

    Blozis, Shelley A; Young, Heather M; Nesbitt, Thomas S; Quinn, Charlene C

    2015-01-01

    Background Type 2 diabetes mellitus is a worldwide challenge. Practice guidelines promote structured self-monitoring of blood glucose (SMBG) for informing health care providers about glycemic control and providing patient feedback to increase knowledge, self-efficacy, and behavior change. Paired glucose testing—pairs of glucose results obtained before and after a meal or physical activity—is a method of structured SMBG. However, frequent access to glucose data to interpret values and recommend actions is challenging. A complete feedback loop—data collection and interpretation combined with feedback to modify treatment—has been associated with improved outcomes, yet there remains limited integration of SMBG feedback in diabetes management. Incorporating telehealth remote monitoring and asynchronous electronic health record (EHR) feedback from certified diabetes educators (CDEs)—specialists in glucose pattern management—employ the complete feedback loop to improve outcomes. Objective The purpose of this study was to evaluate a telehealth remote monitoring intervention using paired glucose testing and asynchronous data analysis in adults with type 2 diabetes. The primary aim was change in glycated hemoglobin (A1c)—a measure of overall glucose management—between groups after 6 months. The secondary aims were change in self-reported Summary of Diabetes Self-Care Activities (SDSCA), Diabetes Empowerment Scale, and Diabetes Knowledge Test. Methods A 2-group randomized clinical trial was conducted comparing usual care to telehealth remote monitoring with paired glucose testing and asynchronous virtual visits. Participants were aged 30-70 years, not using insulin with A1c levels between 7.5% and 10.9% (58-96 mmol/mol). The telehealth remote monitoring tablet computer transmitted glucose data and facilitated a complete feedback loop to educate participants, analyze actionable glucose data, and provide feedback. Data from paired glucose testing were analyzed

  15. Novel flavours paired with glutamate condition increased intake in older adults in the absence of changes in liking.

    PubMed

    Dermiki, Maria; Prescott, John; Sargent, Laura J; Willway, Joanne; Gosney, Margot A; Methven, Lisa

    2015-07-01

    Previous research on the repeat exposure to a novel flavour combined with monosodium glutamate (MSG) has shown an increase in liking and consumption for the particular flavour. The aim of the current work was to investigate whether this could also be observed in the case of older people, since they are most affected by undernutrition in the developed world and ways to increase consumption of food are of significant importance for this particular age group. For this study, 40 older adults (age 65-88) repeatedly consumed potato soup with two novel flavours (lemongrass and cumin) which were either with or without a high level of MSG (5% w/w). A randomized single blind within-subject design was implemented, where each participant was exposed to both soup flavours three times over 6 days, with one of the soup flavours containing MSG. After three repeat exposures, consumption increased significantly for the soups where the flavours had contained MSG during the repeated exposure (mean weight consumed increased from 123 to 164 g, p = 0.017), implying that glutamate conditioned for increased wanting and consumption, despite the fact that the liking for the soup had not increased.

  16. Preadolescent development: case studies in twins.

    PubMed Central

    Frank, R. A.; Cohen, D. J.

    1980-01-01

    The authors studied eight sets of healthy twins, ranging in physical maturity from prepubertal to late pubertal, and their parents, to assess psychological changes in early adolescence. A phase-specific psychosocial regression correlates with the biological onset of puberty. We present preliminary findings related to twinship, parental reactions, and longitudinal development, based on detailed case studies. Parents experienced increased conflict, detachment, and pride in response to their twins' psychosocial development at puberty. The more advanced child in a pair tended to lead in all spheres of adjustment-school success, heterosexual interest, peer friendships, and independent behavior. Although the more advanced child began to break away from his twin, in general the twin relationships remained close. Differences in personality traits and rate of psychosocial development within a twinship tended to remain consistent or to become accentuated. They were occasionally narrowed but rarely reversed from early childhood through early adolescence. Some of the differences were fostered by dissimilar patterns of identifying with the parents. PMID:7195631

  17. Twins: A cloning experience.

    PubMed

    Prainsack, Barbara; Spector, Tim D

    2006-11-01

    Drawing upon qualitative interviews with monozygotic (identical) twins sharing 100% of their genes, and with dizygotic (fraternal) twins and singletons as control groups, this paper explores what it means to be genetically identical. (The twins interviewed were from the TwinsUK register in London.) In the context of the ongoing debate on human reproductive cloning, it examines questions such as: To what extent do identical twins perceive their emotional and physical bond to be a result of their genetic makeup? What would they think if they had been deliberately created genetically identical? How would they feel about being genetically identical to a person who was born a few years earlier or later? First, our respondents ascribed no great significance to the role of genes in their understanding of what it means to be identical twins. Second, the opinion that human reproductive cloning would "interfere with nature", or "contradict God's will", was expressed by our respondents exclusively on the abstract level. The more our respondents were able to relate a particular invented cloning scenario to their own life-worlds, the lower the prevalence of the argument. Third, for all three groups of respondents, the scenario of having been born in one of the other groups was perceived as strange. Fourth, the aspect that our respondents disliked about cloning scenarios was the potential motives of the cloners. Without equating monozygotic twins directly with "clones", these results from "naturally" genetically identical individuals add a new dimension to what a future cloning situation could entail: The cloned person might possibly (a) perceive a close physical and emotional connection to the progenitor as a blessing; (b) suffer from preconceptions of people who regard physical likeness as a sign of incomplete individuality; and (c) perceive the idea of not having been born a clone of a particular person as unpleasant.

  18. On the Heritability of Inspection Time and Its Covariance with IQ: A Twin Study.

    ERIC Educational Resources Information Center

    Luciano, Michelle; Smith, Glen A.; Wright, Margaret J.; Geffen, Gina M.; Geffen, Laurie B.; Martin, Nicholas G.

    2001-01-01

    Used the classical twin design with 390 pairs of twins to study the influence of genetic factors on the large phenotypic variation in inspection time (IT) and whether the well-established IT-IQ association could be explained by a common genetic factor. Findings provide potentially important information for the biological bases of the…

  19. Monozygotic Twins with Asperger Syndrome: Differences in Behaviour Reflect Variations in Brain Structure and Function

    ERIC Educational Resources Information Center

    Belmonte, Matthew K.; Carper, Ruth A.

    2006-01-01

    A pair of monozygotic twins discordant for symptoms of Asperger syndrome was evaluated at the age of 13.45 years using psychometric, morphometric, behavioural, and functional imaging methods. The lower-functioning twin had a smaller brain overall, a smaller right cerebellum, and a disproportionately large left frontal lobe, and manifested almost…

  20. Attentional Regulation in Young Twins with Probable Stuttering, High Nonfluency, and Typical Fluency

    ERIC Educational Resources Information Center

    Felsenfeld, Susan; van Beljsterveldt, Catharina Eugenie Maria; Boomsma, Dorret Irene

    2010-01-01

    Purpose: Using a sample of 20,445 Dutch twins, this study examined the relationship between speech fluency and attentional regulation in children. A secondary objective was to identify etiological overlap between nonfluency and poor attention using fluency-discordant twin pairs. Method: Three fluency groups were created at age 5 using a parent…

  1. Temperament, Emotion, and Cognition at Fourteen Months: The MacArthur Longitudinal Twin Study.

    ERIC Educational Resources Information Center

    Emde, Robert N.; And Others

    1992-01-01

    Assessments of temperament, emotion, cognition, and language acquisition were obtained for 200 pairs of 14-month-old twins. Comparisons between the assessment correlations for identical and fraternal twins indicated an influence of genetics on inhibition, activity, temperament, empathy, negative emotion, spatial memory, categorization skills, and…

  2. Differential Mental Development of 18 Month-Old Same-Sexed and Opposite-Sexed Twins.

    ERIC Educational Resources Information Center

    Black, Kathryn Norcross; Campbell, Kathleen M.

    This paper describes a study which examined the performance of 48 pairs of 18-month-old twins on the Mental Development Scale of the Bayley Scales of Infant Development to determine whether score differences would be found for the three subgroups of identical, fraternal same-sexed, and fraternal opposite-sexed twins. Of the 96 subjects, 46 (23…

  3. Twin Studies in Autism: What Might They Say about Genetic and Environmental Influences

    ERIC Educational Resources Information Center

    Anderson, George M.

    2012-01-01

    Genetic and epigenetic differences exist within monozygote twin-pairs and might be especially important in the expression of autism. Assuming phenotypic differences between monozygotic twins are due to environmental influences may lead to mistaken conclusions regarding the relative genetic and environmental contribution to autism risk.

  4. Evidence for Shared Genetic Risk between ADHD Symptoms and Reduced Mathematics Ability: A Twin Study

    ERIC Educational Resources Information Center

    Greven, Corina U.; Kovas, Yulia; Willcutt, Erik G.; Petrill, Stephen A.; Plomin, Robert

    2013-01-01

    Background: Attention-deficit/hyperactivity disorder (ADHD) symptoms and mathematics ability are associated, but little is known about the genetic and environmental influences underlying this association. Methods: Data came from more than 6,000 twelve-year-old twin pairs from the UK population-representative Twins Early Development Study. Parents…

  5. Etiologies of Associations between Childhood Sleep and Behavioral Problems in a Large Twin Sample.

    ERIC Educational Resources Information Center

    Gregory, Alice M.; Eley, Thalia C.; O'Connor, Thomas G.; Plomin, Robert

    2004-01-01

    Objective: To examine the etiologies of covariation of childhood sleep problems and other behavioral/emotional problems in young children. Method: The parents of more than 6,000 twin pairs provided information on their twins' anxiety, conduct, and hyperactivity at ages 3, 4, and 7 by completing the Strengths and Difficulties Questionnaire.…

  6. Race, zygosity, and mortality among twins: interaction of myth and method.

    PubMed

    Boklage, C E

    1987-01-01

    For epidemiological purposes, it is customary to assume that same-sex (SS) dizygotic (DZ) twin pairs are approximately equal in number to unlike-sex (OS)-DZs, the remainder of the SS pairs being monozygotic (MZ). It is also customary to consider OS-DZs to be epidemiologically representative of all DZs, which can only mean that difference in frequency of any trait between OS and SS twins is due to the MZ fraction of the SS twins. Since this is assumed as a premise, there is little value in its usual appearance as the result. The basic tenet of twin biology, that most twin excess anomalies are due to MZs, is a myth self-perpetuated by a methodological tautology, and is false, at least for mortality. In a consecutively ascertained and prospectively studied sample of 616 twin pairs, over 80% diagnosed for zygosity, it can be shown that the standard assumption mentioned above have given impossible answers. The most probable possible answer is that mortality does not differ greatly with zygosity overall, but that SSDZ mortality is much higher than that of OS twins, and probably even higher than that of MZs. Race differences in the probable answers further suggest that standard assumptions of the Weinberg method may have consistently provided false explanations for race differences in the OS fraction of twin pairs.

  7. The Genetic and Environmental Contributions to Oppositional Defiant Behavior: A Multi-informant Twin Study

    ERIC Educational Resources Information Center

    Hudziak, James J.; Derks, Eske M.; Althoff, Robert R.; Copeland, William; Boomsma, Dorret I.

    2005-01-01

    Objective: To estimate the genetic and environmental contributions to oppositional defiant behavior (ODB) from mother, father, and teacher report using the Conners Revised Short Forms in a large twin sample. Method: ODB data were collected from 1,595 mothers, 1,114 fathers, and 793 teachers of 7-year-old twin pairs from the Netherlands Twin…

  8. Language Development in a Hearing and a Deaf Twin with Simultaneous Bilateral Cochlear Implants

    ERIC Educational Resources Information Center

    Ruggirello, Caterina; Mayer, Connie

    2010-01-01

    This case study is an examination of the language development of a single pair of fraternal twins--one with a profound, sensorineural hearing loss who received simultaneous bilateral cochlear implants at 1 year of age and the other with normal hearing. The purpose of the study was to compare the twins' language development over time from 6 months…

  9. Association between birth weight and neuromotor performance: a twin study.

    PubMed

    Lopes, A A T; Tani, G; Katzmarzyk, P T; Thomis, M A; Maia, J A R

    2014-06-01

    Studies have shown important associations between low birth weight (BW), a variety of morbidities, and reduced motor performance. Using a twin sample, this study aimed to verify (a) the magnitude of the association between BW and neuromotor performance (NMP); (b) if the NMP of twins is within the normal range; and (c) if monozygotic (MZ) and dizygotic (DZ) twins' intra-pair similarities in NMP are of equal magnitude. We sampled 191 twins (78 MZ; 113 DZ distinguished through their DNA), aged 8.9 ± 3.1 years with an average BW of 2246.3 ± 485.4 g; gestational characteristics and sports practices were also assessed. The Zurich Neuromotor test battery, comprising five main tasks, was used; Twins NMP assessments were highly reliable (intra-rater reliability: 0.76-0.99). BW accounted for up to 11% of the total variance of NMP across the zygosity groups. Between 32.7% and 76.9% of children were below the 10th percentile for tasks requiring timing of performance (purely motor task, adaptive fine motor task, dynamic, and static balance), while less than 6.4% of children were below the 10th percentile for associated movements. MZ twins NMP intraclass correlations showed greater similarity than DZ twins in three of the five tasks, suggesting the importance of genetic factors in NMP.

  10. Myasthenia gravis occurring in twins

    PubMed Central

    Namba, T.; Shapiro, M. S.; Brunner, N. G.; Grob, D.

    1971-01-01

    Myasthenia gravis in one member each of two sets of twins is described. A 17 year old girl developed generalized myasthenia gravis at the age of 14 years, while her monozygotic twin sister has remained in good health during a three year period of observation. Another patient was a 19 year old woman with the onset of generalized myasthenia gravis at the age of 11 years, and her dizygotic twin sister has been in good health. Myasthenia gravis has been described in 13 sets of monozygotic twins, seven sets of dizygotic twins, and one set of twins with undetermined zygosity. Both members of twins were affected in five sets of monozygotic twins and one set of twins with undetermined zygosity, and only one twin was affected in the remaining sets of twins. Occurrence of myasthenia gravis in both members of monozygotic twins and in none of dizygotic twins, and frequent familial occurrence of the disease suggest the role of a genetic factor in the pathogenesis of this disease. PMID:5122380

  11. Shared and Unique Genetic and Environmental Influences on Binge Eating and Night Eating: A Swedish Twin Study

    PubMed Central

    Root, Tammy L.; Thornton, Laura; Lindroos, Ann Karin; Stunkard, Albert J.; Lichtenstein, Paul; Pedersen, Nancy L.; Rasmussen, Finn; Bulik, Cynthia M.

    2009-01-01

    We applied twin methodology to female and male twin pairs to further understand the nature of the relation between two behaviors associated with eating disorders—binge eating (BE) and night eating (NE) in an effort to determine the extent of overlap of genetic and environmental factors influencing liability to these behaviors. We calculated heritability estimates for males and females for each behavior and applied bivariate twin modeling to the female data to estimate the genetic and environmental correlation between these two traits. Data on BE and NE were derived from the Swedish Twin Study of Adults: Genes and Environment (STAGE) of the Swedish Twin Registry (STR; N = 11604). Prevalence estimates revealed sex differences with females more likely to endorse BE and males more likely to endorse NE. In males, we were only able to estimate univariate heritabilities due to small sample sizes: The heritability for BE was .74 [95% CI = (0.36, 0.93)] and for NE was .44 [95% CI = (0.24, 0.61)]. The best fitting bivariate model for females included additive genetic and unique environmental factors as well as the genetic correlation between BE and NE. Heritability estimates were 0.70 [95% CI = (0.26, 0.77)] for BE and 0.35 [95% CI = (0.17, 0.52)] for NE. The genetic correlation, 0.66 [95% CI = (0.48, 0.96)] suggests considerable overlap in the genetic factors influencing liability to BE and NE. In females, there is considerable overlap in the genetic factors that contribute to these traits, but the incomplete overlap allows for the influence of independent genetic and environmental factors as well. BE and NE in females are therefore best conceptualized as related but not identical traits. PMID:20188292

  12. Shared and unique genetic and environmental influences on binge eating and night eating: a Swedish twin study.

    PubMed

    Root, Tammy L; Thornton, Laura M; Lindroos, Ann Karin; Stunkard, Albert J; Lichtenstein, Paul; Pedersen, Nancy L; Rasmussen, Finn; Bulik, Cynthia M

    2010-04-01

    We applied twin methodology to female and male twin pairs to further understand the nature of the relation between two behaviors associated with eating disorders-binge eating (BE) and night eating (NE) in an effort to determine the extent of overlap of genetic and environmental factors influencing liability to these behaviors. We calculated heritability estimates for males and females for each behavior and applied bivariate twin modeling to the female data to estimate the genetic and environmental correlation between these two traits. Data on BE and NE were derived from the Swedish Twin study of Adults: Genes and Environment (STAGE) of the Swedish Twin Registry (STR; N=11,604). Prevalence estimates revealed sex differences with females more likely to endorse BE and males more likely to endorse NE. In males, we were only able to estimate univariate heritabilities due to small sample sizes: The heritability for BE was 0.74 [95% CI=(0.36, 0.93)] and for NE was 0.44 [95% CI=(0.24, 0.61)]. The best fitting bivariate model for females included additive genetic and unique environmental factors as well as the genetic correlation between BE and NE. Heritability estimates were 0.70 [95% CI=(0.26, 0.77)] for BE and 0.35 [95% CI=(0.17, 0.52)] for NE. The genetic correlation, 0.66 [95% CI=(0.48, 0.96)] suggests considerable overlap in the genetic factors influencing liability to BE and NE. In females, there is considerable overlap in the genetic factors that contribute to these traits, but the incomplete overlap allows for the influence of independent genetic and environmental factors as well. BE and NE in females are therefore best conceptualized as related but not identical traits.

  13. Shared and unique genetic and environmental influences on binge eating and night eating: a Swedish twin study.

    PubMed

    Root, Tammy L; Thornton, Laura M; Lindroos, Ann Karin; Stunkard, Albert J; Lichtenstein, Paul; Pedersen, Nancy L; Rasmussen, Finn; Bulik, Cynthia M

    2010-04-01

    We applied twin methodology to female and male twin pairs to further understand the nature of the relation between two behaviors associated with eating disorders-binge eating (BE) and night eating (NE) in an effort to determine the extent of overlap of genetic and environmental factors influencing liability to these behaviors. We calculated heritability estimates for males and females for each behavior and applied bivariate twin modeling to the female data to estimate the genetic and environmental correlation between these two traits. Data on BE and NE were derived from the Swedish Twin study of Adults: Genes and Environment (STAGE) of the Swedish Twin Registry (STR; N=11,604). Prevalence estimates revealed sex differences with females more likely to endorse BE and males more likely to endorse NE. In males, we were only able to estimate univariate heritabilities due to small sample sizes: The heritability for BE was 0.74 [95% CI=(0.36, 0.93)] and for NE was 0.44 [95% CI=(0.24, 0.61)]. The best fitting bivariate model for females included additive genetic and unique environmental factors as well as the genetic correlation between BE and NE. Heritability estimates were 0.70 [95% CI=(0.26, 0.77)] for BE and 0.35 [95% CI=(0.17, 0.52)] for NE. The genetic correlation, 0.66 [95% CI=(0.48, 0.96)] suggests considerable overlap in the genetic factors influencing liability to BE and NE. In females, there is considerable overlap in the genetic factors that contribute to these traits, but the incomplete overlap allows for the influence of independent genetic and environmental factors as well. BE and NE in females are therefore best conceptualized as related but not identical traits. PMID:20188292

  14. The Cuban Twin Registry: initial findings and perspectives.

    PubMed

    Marcheco-Teruel, Beatriz; Cobas-Ruiz, Marcia; Cabrera-Cruz, Niviola; Lantigua-Cruz, Araceli; García-Castillo, Elsa; Lardoeyt-Ferrer, Roberto; Robaina-Jiménez, Zoe; Fuentes-Smith, Evelyn; Morales-Calatayud, Francisco; Lemus-Valdés, María Teresa; Portuondo-Sao, Miriam; Comas-Pérez, Lenier; Pérez-Crispí, Juan M; Díaz-De Villal Villa, Thais; Icart-Perera, Emelia; Jordán-Hernández, Aida; Lage-Castellanos, Agustín; Rabell-Piera, Sergio; Llibre-Rodríguez, Juan de Jesús; Valdés-Sosa, Pedro; Valdés-Sosa, Mitchell

    2013-02-01

    The Cuban Twin Registry is a nation-wide, prospective, population-based twin registry comprising all zygosity types and ages. It was initiated in 2004 to study genetic and environmental contributions to complex diseases with high morbidity and mortality in the Cuban population. The database contains extensive information from 55,400 twin pairs enrolled in the period 2004-2006. Additionally, 2,600 new multiple births have been included from 2007 to date. In the past 4 years, more than 130 studies have been carried out using the registry with a classical genetic epidemiological approach in which concordance rates for monozygotic and dizygotic twins and heritability of various disease traits were estimated. This article summarizes the history, registry's methodology, recent research findings, and future directions of work. PMID:23228217

  15. Origins of Individual Differences in Imitation: Links with Language, Pretend Play, and Socially Insightful Behavior in Two-Year-Old Twins

    ERIC Educational Resources Information Center

    McEwen, Fiona; Happe, Francesca; Bolton, Patrick; Rijsdijk, Fruhling; Ronald, Angelica; Dworzynski, Katharina; Plomin, Robert

    2007-01-01

    Imitation, vocabulary, pretend play, and socially insightful behavior were investigated in 5,206 same- and opposite-sex 2-year-old twin pairs in the United Kingdom. Individual differences in imitative ability were due to modest heritability (30%), while environmental factors shared between twins (42%) and unique to each twin (28%) also made…

  16. Monozygotic male twins concordant for Beckwith-Wiedemann syndrome

    SciTech Connect

    Clemens, M.; McPherson, E.; Sherer, C. |

    1994-09-01

    The Beckwith-Wiedemann syndrome (BWS) is a multiple congenital anomaly syndrome characterized by macrosomia, macro glossia, visceromegaly, characteristic facies, and in some cases omphalocele, hypoglycemia, hemihypertrophy, and risk of embryonal tumors. Most cases occur sporadically in chromosomally normal individuals, but a few BWS patients have anomalies of 11p and others have evidence of microduplications or paternal isodisomy in this region. In some families with autosomal dominant transmission, BWS maps to 11p15.5, but the mechanism of transmission is not fully understood. BWS has been reported in 11 sets of MZ twins, including 10 female pairs (9 discordant and 1 partially concordant) and one male pair concordant for both BWS & dup 15q11.2-q13. We report a pair of premature male MZ twins with macroglossia, postnatal overgrowth, characteristic BWS facies, and mild developmental delay. One twin had hypoglycemia, but neither had omphalocele or hemihypertrophy and serial abdominal ultrasounds have been normal. DNA fingerprinting confirmed monozygosity. Chromosome studies showed a marker 11p14.2 in one twin only, and molecular genetic studies of the 11p15.5 region showed no evidence of duplication or isodisomy in either twin.

  17. Association between physical and motor development in childhood: a longitudinal study of Japanese twins.

    PubMed

    Silventoinen, Karri; Pitkäniemi, Janne; Latvala, Antti; Kaprio, Jaakko; Yokoyama, Yoshie

    2014-06-01

    Length and weight in infancy are associated with neurodevelopment, but less is known about growth in other anthropometric measures. In this study we analyzed how the development in length, weight, head circumference, and chest circumference over infancy is associated with motor development in early childhood, using a twin study design. Information on physical development over infancy and the age at achievement of eight developmental milestones over early childhood was collected for 370 Japanese twin pairs. Linear mixed models were used to analyze how physical development is associated with motor development between individual twins, as well as within twin pairs, adjusting the results for shared maternal and postnatal environmental factors. Delayed motor development was associated with smaller body size over infancy, and we also found some suggestive evidence that it was associated with catch-up growth as well. When studying the associations within twin pairs discordant for motor development, similar associations were found. However, chest circumference showed the most robust association within discordant twin pairs. Smaller body size and rapid catch-up growth are associated with delayed motor development. When studying these associations within twin pairs and thus adjusting the results for gestational age as well as many other maternal and postnatal environmental factors, chest circumference showed the most robust association. Chest circumference, rarely used in developed countries, can offer additional information on prenatal conditions relevant for further motor development not achieved by more traditional anthropometric measures.

  18. Is human mating adventitious or the result of lawful choice? A twin study of mate selection.

    PubMed

    Lykken, D T; Tellegen, A

    1993-07-01

    Pairs of middle-aged twins and their spouses provided data on 74 mainly psychological variables. Neither spousal similarity nor idiosyncratic criteria could account for specific mate selection in these 738 couples. Of the twins (and their spouses), 547 independently rated their initial attraction to their twin's mate (or to their spouse's twin): Findings suggest that characteristics both of the chooser and the chosen constrain mate selection only weakly. This article proposes that it is romantic infatuation that commonly determines the final choice from a broad field of potential eligibles and that this phenomenon is inherently random, in the same sense as is imprinting in precocial birds. PMID:8355143

  19. Congenital Systemic Fungus Infection in Twin Prematurity—A Case Report and Literature Review

    PubMed Central

    Chen, Wei-Yu; Chen, Shu-Jen; Tsai, Shu-Fan; Tsao, Pei-Chen; Tang, Ren-Bin; Soong, Wen-Jun

    2015-01-01

    Congenital candidemia sepsis is a serious condition especially for the prematurity. Early recognition is always not the scenario and this leads to high morbidity and mortality. Twin pregnancy complicates the problems further. This report presents a case of congenital candidiasis in a twin preterm and literatures review of five twin pairs with the same scenario. In conclusion, for twin prematurity, if one is suspected to have invasive candidiasis, both of them should receive a full course of antifungal therapy through the intravenous route. PMID:26199798

  20. A reference skeletal dosimetry model for an adult male radionuclide therapy patient based on three-dimensional imaging and paired-image radiation transport

    NASA Astrophysics Data System (ADS)

    Shah, Amish P.

    The need for improved patient-specificity of skeletal dose estimates is widely recognized in radionuclide therapy. Current clinical models for marrow dose are based on skeletal mass estimates from a variety of sources and linear chord-length distributions that do not account for particle escape into cortical bone. To predict marrow dose, these clinical models use a scheme that requires separate calculations of cumulated activity and radionuclide S values. Selection of an appropriate S value is generally limited to one of only three sources, all of which use as input the trabecular microstructure of an individual measured 25 years ago, and the tissue mass derived from different individuals measured 75 years ago. Our study proposed a new modeling approach to marrow dosimetry---the Paired Image Radiation Transport (PIRT) model---that properly accounts for both the trabecular microstructure and the cortical macrostructure of each skeletal site in a reference male radionuclide patient. The PIRT model, as applied within EGSnrc, requires two sets of input geometry: (1) an infinite voxel array of segmented microimages of the spongiosa acquired via microCT; and (2) a segmented ex-vivo CT image of the bone site macrostructure defining both the spongiosa (marrow, endosteum, and trabeculae) and the cortical bone cortex. Our study also proposed revising reference skeletal dosimetry models for the adult male cancer patient. Skeletal site-specific radionuclide S values were obtained for a 66-year-old male reference patient. The derivation for total skeletal S values were unique in that the necessary skeletal mass and electron dosimetry calculations were formulated from the same source bone site over the entire skeleton. We conclude that paired-image radiation-transport techniques provide an adoptable method by which the intricate, anisotropic trabecular microstructure of the skeletal site; and the physical size and shape of the bone can be handled together, for improved

  1. Progression in substance use initiation: A multilevel discordant monozygotic twin design.

    PubMed

    Richmond-Rakerd, Leah S; Slutske, Wendy S; Deutsch, Arielle R; Lynskey, Michael T; Agrawal, Arpana; Madden, Pamela A F; Bucholz, Kathleen K; Heath, Andrew C; Martin, Nicholas G

    2015-08-01

    Considerable attention has been paid to the "gateway" pattern of drug use initiation in which individuals progress from tobacco and alcohol use to cannabis and other illicit drugs. The extent to which this sequence reflects a causal impact of licit substance use on illicit substance involvement remains unclear. Clarifying the mechanisms underlying substance use initiation may help inform our understanding of risk for psychopathology, as increasing research is demonstrating associations between initiation patterns and heavier involvement. This study examined patterns of substance use initiation using a discordant twin design. Participants were 3,476 monozygotic twins (37% male) from the Australian Twin Registry who reported on their ages of tobacco, alcohol, and cannabis initiation. Multilevel proportional hazard regression models were used to (a) estimate within-twin-pair and between-twin-pair contributions to associations between the ages of onset of different drugs; and (b) examine whether the magnitude of effects differed as a function of the order of substance use initiation. Finding significant effects within twin pairs would support the hypothesis that the age of initiation of a substance causally influences the age of initiation of a subsequent substance. Finding significant effects between twin pairs would support the operation of familial influences that explain variation in the ages of initiation of multiple drugs. Within-twin-pair effects for typical patterns were modest. When initiation was atypical, however, larger within-twin-pair effects were observed and causal influences were more strongly implicated. Results support the utility of examining the timing and ordering of substance use initiation within sophisticated, genetically informative designs. PMID:26098047

  2. Progression in Substance Use Initiation: A Multilevel Discordant Monozygotic Twin Design

    PubMed Central

    Richmond-Rakerd, Leah S.; Slutske, Wendy S.; Deutsch, Arielle R.; Lynskey, Michael T.; Agrawal, Arpana; Madden, Pamela A.F.; Bucholz, Kathleen K.; Heath, Andrew C.; Martin, Nicholas G.

    2015-01-01

    Considerable attention has been paid to the “gateway” pattern of drug use initiation in which individuals progress from tobacco and alcohol use to cannabis and other illicit drugs. The extent to which this sequence reflects a causal impact of licit substance use on illicit substance involvement remains unclear. Clarifying the mechanisms underlying substance use initiation may help inform our understanding of risk for psychopathology, as increasing research is demonstrating associations between initiation patterns and heavier involvement. This study examined patterns of substance use initiation using a discordant twin design. Participants were 3,476 monozygotic twins (37% male) from the Australian Twin Registry who reported on their ages of tobacco, alcohol, and cannabis initiation. Multilevel proportional hazard regression models were employed to (a) estimate within-twin-pair and between-twin-pair contributions to associations between the ages of onset of different drugs; and (b) examine whether the magnitude of effects differed as a function of the order of substance use initiation. Finding significant effects within twin pairs would support the hypothesis that the age of initiation of one substance causally influences the age of initiation of a subsequent substance. Finding significant effects between twin pairs would support the operation of familial influences that explain variation in the ages of initiation of multiple drugs. Within-twin-pair effects for typical patterns were modest. When initiation was atypical, however, larger within-twin-pair effects were observed and causal influences were more strongly implicated. Results support the utility of examining the timing and ordering of substance use initiation within sophisticated, genetically informative designs. PMID:26098047

  3. Testing the equal environments assumption in the Children of Twins design.

    PubMed

    Koenig, Laura B; Jacob, Theodore; Haber, Jon Randolph; Xian, Hong

    2010-07-01

    In a Children of Twins (COT) design, the environmental and genetic risk of a child is, in part, dependent upon the status of the father and the father's cotwin. The logic of the COT method breaks down if the zygosity of the twin pair is confounded with the environment provided to the child (a version of the Equal Environment Assumption, EEA). If MZ twin fathers see each other more often than DZ twin fathers, and a child's uncle is the affected twin in discordant pairs, this could increase the environmental risk of children of MZ over that of DZ discordant twins. The current study was designed to test the EEA in the COT design, specifically in children of alcohol and drug dependent fathers. Results indicated that MZ twins did have more contact than DZ twins. Regression analyses were conducted to predict child externalizing symptom counts from father's zygosity group status, level of contact with father's cotwin, and their interaction. Results found no significant interaction between father's zygosity and the higher level of cotwin contact (seen in MZ twins) in predicting several measures of offspring externalizing risk. The results of this study suggested that the COT design does not confound zygosity with differences in environmental risk exposure, findings that support the validity of the EEA within this research context.

  4. Aryl hydrocarbon hydroxylase in cultured lymphocytes of twins.

    PubMed Central

    Paigen, B; Ward, E; Steenland, K; Houten, L; Gurtoo, H L; Minowada, J

    1978-01-01

    Measurement of aryl hydrocarbon hydroxylase (AHH) in cultured lymphocytes of 18 monozygotic and 30 dizygotic twin pairs showed that basal and induced AHH activity and AHH inducibility are heritable traits. The data are consistent with AHH inducibility being determined by a single or a very few polymorphic genes. PMID:569973

  5. A Twin Study of Objectively Assessed Personality in Childhood.

    ERIC Educational Resources Information Center

    Plomin, Robert; Foch, Terryl T.

    1980-01-01

    Obtained objective measures of activity, fidgeting, vigilance, selective attention, and aggression for a sample of 87 twin pairs in late childhood. Little evidence for genetic influence on behavior was found. Between-family environmental sources of variance were far more important than within-family factors. (Author/RH)

  6. "Generalist Genes" and Mathematics in 7-Year-Old Twins

    ERIC Educational Resources Information Center

    Kovas, Y.; Harlaar, N.; Petrill, S. A.; Plomin, R.

    2005-01-01

    Mathematics performance at 7 years as assessed by teachers using UK national curriculum criteria has been found to be highly heritable. For almost 3000 pairs of 7-year-old same-sex twins, we used multivariate genetic analysis to investigate the extent to which these genetic effects on mathematics performance overlap with genetic effects on reading…

  7. A Longitudinal Twin Study of Intelligence in the Second Year.

    ERIC Educational Resources Information Center

    Reznick, J. Steven; And Others

    1997-01-01

    Examined data from 408 pairs of identical, same-sex fraternal twins at 14, 20, and 24 months to assess cognitive development and to identify genetic and environmental influences on phenotypic similarity. Found various patterns of development for separate constructs, for females versus males on each construct, and for individuals across constructs.…

  8. Sex-discordant monochorionic twins with blood and tissue chimerism.

    PubMed

    Rodriguez-Buritica, David; Rojnueangnit, Kitiwan; Messiaen, Ludwine M; Mikhail, Fady M; Robin, Nathaniel H

    2015-04-01

    We report on a pair of normally conceived monochorionic/dizygotic (MC/DZ) sex discordant twins. The comparison of blood and skin genotypes revealed that the chimerism was also present in the skin. We conjecture about the developmental origins of this case.

  9. Heredity, Environment, & Personality: A Study of 850 Sets of Twins.

    ERIC Educational Resources Information Center

    Loehlin, John C.; Nichols, Robert C.

    This book reports on a study of 850 pairs of twins who were tested to determine the influence of heredity and environment on individual differences in personality, academic ability, and interests. It presents the background, research design, and procedure of the study, tabulations of the test results, and extensive analyses of the findings.…

  10. Generalist Genes and Cognitive Abilities in Chinese Twins

    ERIC Educational Resources Information Center

    Chow, Bonnie Wing-Yin; Ho, Connie Suk-Han; Wong, Simpson Wai-Lap; Waye, Mary M. Y.; Bishop, Dorothy V. M.

    2013-01-01

    This study considered how far nonverbal cognitive, language and reading abilities are affected by common genetic influences in a sample of 312 typically developing Chinese twin pairs aged from 3 to 11 years. Children were individually given tasks of Chinese word reading, receptive vocabulary, phonological memory, tone awareness, syllable and rhyme…

  11. Personality and Grip Strength Relationships Between Monozygous and Dizygous Twins.

    ERIC Educational Resources Information Center

    Fisher, A. Craig; And Others

    The purposes of this study were a) to investigate the relationship between grip strength and the measures of age, height, weight, and the personality traits revealed by the Comrey Personality and Attitude Factor Scales and b) to assess the influence of heredity on height, weight, and grip strength. Fifty-eight pairs of twins (MZ, 30 and DZ, 28)…

  12. Twins, Triplets, Multiple Births

    MedlinePlus

    ... from alone. Multiple births are up in the United States. More women are having babies after age 30 and more are taking fertility drugs. Both boost the chance of carrying more than one baby. A family history of twins also makes multiples more likely. Years ...

  13. Anaesthesia of conjoined twins.

    PubMed

    Kobylarz, Krzysztof

    2014-01-01

    Conjoined twins have been a source of fascination to the public and the medical profession for centuries. Their birth was initially viewed as an ominous sign of impending disaster. Since Middle Ages into the 19th century they were regarded as monstrosities and were exhibited at circuses and sideshows. The frequency of conjoined twins is approximately 1 in 50,000 gestation, but many of them die in utero, are terminated or stillborn. The true incidence is estimated to be 1 in 200,000 live births. This article gives an overview of Siamese twins and of the prenatal diagnosis in assessing the prognosis, anaesthetic and post-natal surgical management and outcome. Anaesthesia for conjoined twins surgery, whether prior to or for separation, is an enormous challenge to the anaesthesiologist. The site and complexity of the conjunction affect management of the airway, an intravenous access, the extent of blood and number of surgical specialties involved. Preoperative assessment and planning with interdisciplinary communication and cooperation is vital to the success of the operations. Meticulous attention to detail, monitoring and vigilance are mandatory. PMID:24858973

  14. Identical Twins Raised Apart

    ERIC Educational Resources Information Center

    Farnsworth, David L.

    2015-01-01

    This article describes a bivariate data set that is interesting to students. Indeed, this particular data set, which involves twins and IQ, has sparked more student interest than any other set that I have presented. Specific uses of the data set are presented.

  15. Discordant phenotypes in monozygotic twins with identical de novo WT1 mutation.

    PubMed

    Yu, Zihua; Yang, Yonghui; Feng, Dongning

    2012-06-01

    Mutations in the WT1 gene, leading to Denys-Drash syndrome and Frasier syndrome, can also cause isolated steroid-resistant nephrotic syndrome (ISRNS). Previous studies have reported six pairs of monozygotic twins with WT1 mutations, including one presenting with discordant phenotypes with identical WT1 mutations being of paternal origin and five pairs of monozygotic twins presenting the same phenotype with identical WT1 mutations. In this study, we report on female monozygotic twins showing discordant phenotypes with an identical de novo WT1 mutation, R394W, and presenting incomplete Denys-Drash syndrome and ISRNS. PMID:26069768

  16. Sleep Duration and Area-Level Deprivation in Twins

    PubMed Central

    Watson, Nathaniel F.; Horn, Erin; Duncan, Glen E.; Buchwald, Dedra; Vitiello, Michael V.; Turkheimer, Eric

    2016-01-01

    Study Objectives: We used quantitative genetic models to assess whether area-level deprivation as indicated by the Singh Index predicts shorter sleep duration and modifies its underlying genetic and environmental contributions. Methods: Participants were 4,218 adult twin pairs (2,377 monozygotic and 1,841 dizygotic) from the University of Washington Twin Registry. Participants self-reported habitual sleep duration. The Singh Index was determined by linking geocoding addresses to 17 indicators at the census-tract level using data from Census of Washington State and Census Tract Cartographic Boundary Files from 2000 and 2010. Data were analyzed using univariate and bivariate genetic decomposition and quantitative genetic interaction models that assessed A (additive genetics), C (common environment), and E (unique environment) main effects of the Singh Index on sleep duration and allowed the magnitude of residual ACE variance components in sleep duration to vary with the Index. Results: The sample had a mean age of 38.2 y (standard deviation [SD] = 18), and was predominantly female (62%) and Caucasian (91%). Mean sleep duration was 7.38 h (SD = 1.20) and the mean Singh Index score was 0.00 (SD = 0.89). The heritability of sleep duration was 39% and the Singh Index was 12%. The uncontrolled phenotypic regression of sleep duration on the Singh Index showed a significant negative relationship between area-level deprivation and sleep length (b = −0.080, P < 0.001). Every 1 SD in Singh Index was associated with a ∼4.5 min change in sleep duration. For the quasi-causal bivariate model, there was a significant main effect of E (b0E = −0.063; standard error [SE] = 0.30; P < 0.05). Residual variance components unique to sleep duration were significant for both A (b0Au = 0.734; SE = 0.020; P < 0.001) and E (b0Eu = 0.934; SE = 0.013; P < 0.001). Conclusions: Area-level deprivation has a quasi-causal association with sleep duration, with greater deprivation being related to

  17. Non-additive and Additive Genetic Effects on Extraversion in 3314 Dutch Adolescent Twins and Their Parents

    PubMed Central

    Rebollo-Mesa, Irene; Hudziak, James J.; Willemsen, Gonneke; Boomsma, Dorret I.

    2012-01-01

    The influence of non-additive genetic influences on personality traits has been increasingly reported in adult populations. Less is known, however, with respect to younger samples. In this study, we examine additive and non-additive genetic contributions to the personality trait of extraversion in 1,689 Dutch twin pairs, 1,505 mothers and 1,637 fathers of the twins. The twins were on average 15.5 years (range 12–18 years). To increase statistical power to detect non-additive genetic influences, data on extraversion were also collected in parents and simultaneously analyzed. Genetic modeling procedures incorporating age as a potential modifier of heritability showed significant influences of additive (20–23%) and non-additive genetic factors (31–33%) in addition to unshared environment (46–48%) for adolescents and for their parents. The additive genetic component was slightly and positively related to age. No significant sex differences were found for either extraversion means or for the magnitude of the genetic and environmental influences. There was no evidence of non-random mating for extraversion in the parental generation. Results show that in addition to additive genetic influences, extraversion in adolescents is influenced by non-additive genetic factors. PMID:18240014

  18. Why Aren't Identical Twins Linguistically Identical? Genetic, Prenatal and Postnatal Factors

    ERIC Educational Resources Information Center

    Stromswold, Karin

    2006-01-01

    Results of twin studies clearly demonstrate that genetic factors play an important role in the rate of language acquisition and linguistic proficiency attained by normal and impaired children and adults [see Stromswold, K. (2001). The heritability of language: A review and meta-analysis of twin, adoption and linkage studies. "Language," 77,…

  19. Genetic and Environmental Influences on Extreme Personality Dispositions in Adolescent Female Twins

    ERIC Educational Resources Information Center

    Pergadia, Michele L.; Madden, Pamela A. F.; Lessov, Christina N.; Todorov, Alexandre A.; Bucholz, Kathleen K.; Martin, Nicholas G.; Heath, Andrew C.

    2006-01-01

    Background: The objective was to determine whether the pattern of environmental and genetic influences on deviant personality scores differs from that observed for the normative range of personality, comparing results in adolescent and adult female twins. Methods: A sample of 2,796 female adolescent twins ascertained from birth records provided…

  20. Planets and satellites: tectonic twins

    NASA Astrophysics Data System (ADS)

    Kochemasov, G. G.

    2015-10-01

    There are only three solid planet-satellite pairs in the Solar system: Earth -Moon, Mars -Phobos, Pluto - Charon. For the first two pairs tectonic analogies were shown and explained by moving them in one circumsolar orbit. As it is known from the wave planetology [3, 4, 6], "orbits make structures". For the third pair the same was stated as a prediction based on this fundamental rule. Global tectonic forms of wave origin appear in cosmic bodies because they move in keplerian orbits with periodically changing accelerations. Warping bodies waves have a stationary character and obeying wave harmonics lengths. Starting from the fundamental 2πR-long wave 1 making the ubiquitous tectonic dichotomy (two-face appearance) warping wave lengths descend along harmonics. Very prominent along with the wave 1 are waves 2 responsible for tectonic sectoring superimposed on the wave 1 segments. Practically all bodies have traces of shorter waves making numerous polygons (rings) often confused with impact craters. Earth and the Moon moving in one circumsolar orbit both are distorted by wave 1, wave 2 and wave 4 features aligned along extent tectonic lines [4, 5]. At Earth they are: Pacific Ocean (2πR-structure) and Indian Ocean (πR-structure) from both ends with Malay Archipelago (πR/4-structure) in the middle. At Moon they are: Procellarum Ocean (2πR) and SPA Basin (πR) from ends and Mare Orientale (πR/4) in the middle. A regular disposition is surprising. Both Oceans and Basin occur on opposite hemispheres, lying in the middle both ring structures occur in the boundary between two hemispheres and are of the same relative size. These triads stretch along lines parallel to the equator (Earth) and with the angle about 30 degrees to it (Moon) indicating at a different orientation of the rotation axes in the ancient time [2]. On the whole, one could speak about a "lunar mould" of Earth [5] (Fig. 1-3). Another tectonic twin is the pair Mars -Phobos. Both bodies sharing one

  1. Brazilian Twin Registry: A Bright Future for Twin Studies/Twin Research: Twin Study of Alcohol Consumption and Mortality; Oxygen Uptake in Adolescent Twins/In the News: Superfecundated Twins In Vietnam; Adolescent Twin Relations; Twin and Triplet Co-Workers; A Special Twin Ultrasound; Monozygotic Twins With Different Skin Color; Identical Twin Returns from Space.

    PubMed

    Segal, Nancy L

    2016-06-01

    The establishment of the Brazilian Twin Registry for the study of genetic, social, and cultural influences on behavior is one of eleven newly funded projects in the Department of Psychology at the University of São Paulo. These 11 interrelated projects form the core of the university's Center for Applied Research on Well-Being and Human Behavior. An overview of the planned twin research and activities to date is presented. Next, two recent twin studies are reviewed, one on the relationship between alcohol consumption and mortality, and the other on factors affecting maximal oxygen uptake. Twins cited in the media include the first identified superfecundated twins in Vietnam, adolescent twin relations, twins and triplets who work together, monozygotic twins with different skin tones and a co-twin control study that addresses the effects of space travel.

  2. Brazilian Twin Registry: A Bright Future for Twin Studies/Twin Research: Twin Study of Alcohol Consumption and Mortality; Oxygen Uptake in Adolescent Twins/In the News: Superfecundated Twins In Vietnam; Adolescent Twin Relations; Twin and Triplet Co-Workers; A Special Twin Ultrasound; Monozygotic Twins With Different Skin Color; Identical Twin Returns from Space.

    PubMed

    Segal, Nancy L

    2016-06-01

    The establishment of the Brazilian Twin Registry for the study of genetic, social, and cultural influences on behavior is one of eleven newly funded projects in the Department of Psychology at the University of São Paulo. These 11 interrelated projects form the core of the university's Center for Applied Research on Well-Being and Human Behavior. An overview of the planned twin research and activities to date is presented. Next, two recent twin studies are reviewed, one on the relationship between alcohol consumption and mortality, and the other on factors affecting maximal oxygen uptake. Twins cited in the media include the first identified superfecundated twins in Vietnam, adolescent twin relations, twins and triplets who work together, monozygotic twins with different skin tones and a co-twin control study that addresses the effects of space travel. PMID:27121223

  3. Early onset alcohol use and self-harm: A discordant twin analysis

    PubMed Central

    Few, Lauren R.; Werner, Kimberly B.; Sartor, Carolyn E.; Trull, Timothy; Nock, Matthew K.; Bucholz, Kathleen K.; Deitz, Sarah K.; Glowinski, Anne L.; Martin, Nicholas G.; Nelson, Elliot C.; Statham, Dixie J.; Madden, Pamela A. F.; Heath, Andrew; Lynskey, Michael T.; Agrawal, Arpana

    2015-01-01

    Background Self-harm has considerable societal and economic costs and has been extensively studied in relation to alcohol involvement. Whereas early onset alcohol use (EAU) has been causally linked to maladaptive clinical outcomes, its association with self-harm is less well characterized. The current study aimed to further examine the link between EAU and both non-suicidal self-injury (NSSI) and suicide attempt (SA), and elucidate shared familial and causal/individual-specific pathways that explain this co-occurrence. Methods Using data from 6,082 Australian same-sex twin pairs (1,732 MZ and 1,309 DZ), ages 23-40, we examined prevalence rates of NSSI and SA among twin pairs concordant and discordant for EAU. Conditional logistic regression, controlling for early clinical covariates and the influence of zygosity on EAU, was used to examine the odds ratio (OR) of self-harm within twin pairs discordant for EAU. Results Prevalence rates of both NSSI and SA were highest among twin pairs concordant for EAU and for twins who reported EAU within discordant twin pairs. Results from discordant twin analyses revealed nearly four-fold increased odds of SA for the twin who endorsed EAU, and this OR was equal across monozygotic (MZ) and dizygotic (DZ) twins. EAU also was associated with elevated odds of NSSI (OR=7.62), although this was only the case for DZ twins in discordant pairs. Conclusions The equivalent increase in odds of SA for both MZ and DZ twins suggests that causal or individual-specific influences explain the link between EAU and SA. For NSSI, elevated odds for DZ twins and nonsignificant findings for MZ twins implicate correlated genetic factors in the association between EAU and NSSI. Future studies should test mechanisms through which EAU may causally influence SA, as well as examine whether genetic risk for third variables (e.g., negative urgency, stress reactivity) may explain the genetic overlap between EAU and NSSI. PMID:26463647

  4. Special forms in twin pregnancy - ACARDIAC TWIN/ Twin reversed arterial perfusion (TRAP) sequence

    PubMed Central

    Anca, FA; Negru, A; Mihart, AE; Grigoriu, C; Bohîlțea, RE; Șerban, A

    2015-01-01

    Twin pregnancy generally represents a high-risk pregnancy, but monozygous twin pregnancy is a real challenge for the obstetrician due to the serious complications that may occur during its evolution. A very rare, severe complication of monozygous twin pregnancy, which we recently dealt with in the Obstetrics and Gynecology Department of the University Emergency Hospital Bucharest, was a monochorionic monoamniotic twin pregnancy with acardiac twin (TRAP). One of the fetuses (acardiac twin) presented a rudimentary unfunctional heart or even no heart at all, underdeveloped inferior part of the body and head, being transfused by the other fetus with a normal heart (pumping twin) by one superficial arterio-arterial anastomosis through which blood pumped backwards. The understanding of these cases is mandatory in order to offer maximum survival and heath chances to the viable fetus. Abbreviations: RFA = radiofrequency ablation, TRAP = reversed arterial perfusion PMID:26664482

  5. Twin-to-twin transfusion syndrome: a case study.

    PubMed

    Giconi, Stephanie S

    2013-02-01

    Twin-to-twin transfusion syndrome (TTTS) is a disease that affects roughly 15% of monochorionic twins. Although TTTS is not extremely prevalent, the rate of mortality and morbidly approaches 100% without early detection and treatment. The following case study is a triplet pregnancy that included a set of monochorionic twins affected by TTTS. Typically, it is assumed that monochorionicity can identify the zygosity of twins, which was disproven in this case. Research indicates that there has been an increased rate of monochorionic twins with in vitro fertilization. There is great debate about the most appropriate treatment modality for TTTS. Perinatal treatment followed by neonatal management is the standard of care for TTTS. Implications for the neonatal nurse practitioner and care for the patients are discussed.

  6. Treatment responses to tooth whitening in twins.

    PubMed

    Corby, Patricia M A; Biesbrock, Aaron; Gerlach, Robert; Corby, Andrea L; Moreira, Alexandre; Schork, Nicholas J; Bretz, Walter A

    2014-02-01

    The aim of this study was to determine heritability estimates of treatment responses to a 10% hydrogen peroxide strip-based whitening system in twins. Eighty-five twin pairs were randomly assigned to 10% hydrogen peroxide whitening strips or placebo strips without peroxide. Both twins (monozygotic or dizygotic) received the same treatment. Maxillary teeth were treated for 30 minutes twice daily for 7 days. Efficacy was measured objectively as L* (light-dark), a* (red-green), and b* (yellow-blue) color change from digital images at baseline (∆) and day 8. Heritability estimates for tooth whitening treatment responses for changes from day 8 to baseline were obtained using variance-component methodologies. Whitening treatment responses were highly heritable (h(2) = 71.0) for ∆b* and ∆a*(p < .0001), but not for ∆L* (h(2) = 27.0), which was essentially modulated by environmental factors. This study has demonstrated that both genetic and environmental factors significantly contributed to seven-day whitening treatment responses achieved with 10% hydrogen peroxide strips.

  7. Challenges of Twin Pregnancy

    PubMed Central

    Wilson, Lynn M.; Hose, Patricia M.

    1991-01-01

    Family physicians have an important role in the diagnosis and management of twin pregnancies. Optimal antepartum management begins with early detection. Provision of patient education about the risks of the pregnancy is important. Intrapartum management is dependent on gestation age, placentation, fetal presentation, and fetal well-being. Anticipatory guidance and ongoing support should be provided for postpartum issues, such as breast-feeding and family adjustment. PMID:21229108

  8. Characterizing Blood Metabolomics Profiles Associated with Self-Reported Food Intakes in Female Twins

    PubMed Central

    Pallister, Tess; Jennings, Amy; Mohney, Robert P.; Yarand, Darioush; Mangino, Massimo; Cassidy, Aedin; MacGregor, Alexander; Spector, Tim D.; Menni, Cristina

    2016-01-01

    Using dietary biomarkers in nutritional epidemiological studies may better capture exposure and improve the level at which diet-disease associations can be established and explored. Here, we aimed to identify and evaluate reproducibility of novel biomarkers of reported habitual food intake using targeted and non-targeted metabolomic blood profiling in a large twin cohort. Reported intakes of 71 food groups, determined by FFQ, were assessed against 601 fasting blood metabolites in over 3500 adult female twins from the TwinsUK cohort. For each metabolite, linear regression analysis was undertaken in the discovery group (excluding MZ twin pairs discordant [≥1 SD apart] for food group intake) with each food group as a predictor adjusting for age, batch effects, BMI, family relatedness and multiple testing (1.17x10-6 = 0.05/[71 food groups x 601 detected metabolites]). Significant results were then replicated (non-targeted: P<0.05; targeted: same direction) in the MZ discordant twin group and results from both analyses meta-analyzed. We identified and replicated 180 significant associations with 39 food groups (P<1.17x10-6), overall consisting of 106 different metabolites (74 known and 32 unknown), including 73 novel associations. In particular we identified trans-4-hydroxyproline as a potential marker of red meat intake (0.075[0.009]; P = 1.08x10-17), ergothioneine as a marker of mushroom consumption (0.181[0.019]; P = 5.93x10-22), and three potential markers of fruit consumption (top association: apple and pears): including metabolites derived from gut bacterial transformation of phenolic compounds, 3-phenylpropionate (0.024[0.004]; P = 1.24x10-8) and indolepropionate (0.026[0.004]; P = 2.39x10-9), and threitol (0.033[0.003]; P = 1.69x10-21). With the largest nutritional metabolomics dataset to date, we have identified 73 novel candidate biomarkers of food intake for potential use in nutritional epidemiological studies. We compiled our findings into the Diet

  9. Characterizing Blood Metabolomics Profiles Associated with Self-Reported Food Intakes in Female Twins.

    PubMed

    Pallister, Tess; Jennings, Amy; Mohney, Robert P; Yarand, Darioush; Mangino, Massimo; Cassidy, Aedin; MacGregor, Alexander; Spector, Tim D; Menni, Cristina

    2016-01-01

    Using dietary biomarkers in nutritional epidemiological studies may better capture exposure and improve the level at which diet-disease associations can be established and explored. Here, we aimed to identify and evaluate reproducibility of novel biomarkers of reported habitual food intake using targeted and non-targeted metabolomic blood profiling in a large twin cohort. Reported intakes of 71 food groups, determined by FFQ, were assessed against 601 fasting blood metabolites in over 3500 adult female twins from the TwinsUK cohort. For each metabolite, linear regression analysis was undertaken in the discovery group (excluding MZ twin pairs discordant [≥1 SD apart] for food group intake) with each food group as a predictor adjusting for age, batch effects, BMI, family relatedness and multiple testing (1.17x10-6 = 0.05/[71 food groups x 601 detected metabolites]). Significant results were then replicated (non-targeted: P<0.05; targeted: same direction) in the MZ discordant twin group and results from both analyses meta-analyzed. We identified and replicated 180 significant associations with 39 food groups (P<1.17x10-6), overall consisting of 106 different metabolites (74 known and 32 unknown), including 73 novel associations. In particular we identified trans-4-hydroxyproline as a potential marker of red meat intake (0.075[0.009]; P = 1.08x10-17), ergothioneine as a marker of mushroom consumption (0.181[0.019]; P = 5.93x10-22), and three potential markers of fruit consumption (top association: apple and pears): including metabolites derived from gut bacterial transformation of phenolic compounds, 3-phenylpropionate (0.024[0.004]; P = 1.24x10-8) and indolepropionate (0.026[0.004]; P = 2.39x10-9), and threitol (0.033[0.003]; P = 1.69x10-21). With the largest nutritional metabolomics dataset to date, we have identified 73 novel candidate biomarkers of food intake for potential use in nutritional epidemiological studies. We compiled our findings into the Diet

  10. Pick a Pair. Pancake Pairs

    ERIC Educational Resources Information Center

    Miller, Pat

    2005-01-01

    Cold February weather and pancakes are a traditional pairing. Pancake Day began as a way to eat up the foods that were abstained from in Lent--traditionally meat, fat, eggs and dairy products. The best-known pancake event is The Pancake Day Race in Buckinghamshire, England, which has been run since 1445. This column describes pairs of books that…

  11. Niobium and tantalum: indispensable twins

    USGS Publications Warehouse

    Schulz, Klaus; Papp, John

    2014-01-01

    Niobium and tantalum are transition metals almost always paired together in nature. These “twins” are difficult to separate because of their shared physical and chemical properties. In 1801, English chemist Charles Hatchett uncovered an unknown element in a mineral sample of columbite; John Winthrop found the sample in a Massachusetts mine and sent it to the British Museum in London in 1734. The name columbium, which Hatchet named the new element, came from the poetic name for North America—Columbia—and was used interchangeably for niobium until 1949, when the name niobium became official. Swedish scientist Anders Ekberg discovered tantalum in 1802, but it was confused with niobium, because of their twinned properties, until 1864, when it was recognized as a separate element. Niobium is a lustrous, gray, ductile metal with a high melting point, relatively low density, and superconductor properties. Tantalum is a dark blue-gray, dense, ductile, very hard, and easily fabricated metal. It is highly conductive to heat and electricity and renowned for its resistance to acidic corrosion. These special properties determine their primary uses and make niobium and tantalum indispensable.

  12. Deformation Twinning in Zirconium: Direct Experimental Observations and Polycrystal Plasticity Predictions

    NASA Astrophysics Data System (ADS)

    Singh, Jaiveer; Mahesh, Sivasambu; Kumar, Gulshan; Pant, Prita; Srivastava, D.; Dey, G. K.; Saibaba, N.; Samajdar, I.

    2015-11-01

    Deformation twinning was directly observed in three commercial zirconium alloy samples during split channel die plane-strain compression. One pair of samples had similar starting texture but different grain size distributions, while another pair had similar grain size distribution but different starting textures. Extension twinning was found to be more sensitive to the starting texture than to the grain size distribution. Also, regions of intense deformation near grain boundaries were observed. A hierarchical binary tree-based polycrystal plasticity model, implementing the Chin-Hosford-Mendorf twinning criterion, captured the experimentally observed twinning grains' lattice orientation distribution, and the twin volume fraction evolution, provided the critical resolved shear stress for extension twinning, τ0 , was assumed much larger than any of the values reported in the literature, based on the viscoplastic self-consistent model. A comparison of the models suggests that τ0 obtained using the present model and the viscoplastic self-consistent models physically correspond to the critical stress required for twin nucleation, and twin growth, respectively.

  13. Tribute to dr louis keith: twin and physician extraordinaire/twin research reports: influences on asthma severity; chimerism revisited; DNA strand break repair/media reports: twins born apart; elevated twin frequencies; celebrity father of twins; conjoined twinning.

    PubMed

    Segal, Nancy L

    2014-10-01

    The International Society for Twin Studies has lost a valued friend and colleague. Dr Louis Keith, Emeritus Professor of Obstetrics and Gynecology at Northwestern University, in Chicago, passed away on Sunday, July 6, 2014. His life and work with twins will be acknowledged at the November 2014 International Twin Congress in Budapest, Hungary. Next, twin research reports on the severity of asthma symptoms, a case of chimerism, and factors affecting DNA breakage and repair mechanisms are reviewed. Media reports cover twins born apart, elevated twin frequencies, a celebrity father of twins, and a family's decision to keep conjoined twins together. PMID:25213730

  14. Tribute to dr louis keith: twin and physician extraordinaire/twin research reports: influences on asthma severity; chimerism revisited; DNA strand break repair/media reports: twins born apart; elevated twin frequencies; celebrity father of twins; conjoined twinning.

    PubMed

    Segal, Nancy L

    2014-10-01

    The International Society for Twin Studies has lost a valued friend and colleague. Dr Louis Keith, Emeritus Professor of Obstetrics and Gynecology at Northwestern University, in Chicago, passed away on Sunday, July 6, 2014. His life and work with twins will be acknowledged at the November 2014 International Twin Congress in Budapest, Hungary. Next, twin research reports on the severity of asthma symptoms, a case of chimerism, and factors affecting DNA breakage and repair mechanisms are reviewed. Media reports cover twins born apart, elevated twin frequencies, a celebrity father of twins, and a family's decision to keep conjoined twins together.

  15. Statistical analyses of monozygotic and dizygotic twinning rates.

    PubMed

    Fellman, Johan

    2013-12-01

    The French mathematician Bertillon reasoned that the number of dizygotic (DZ) pairs would equal twice the number of twin pairs of unlike sexes. The remaining twin pairs in a sample would presumably be monozygotic (MZ). Weinberg restated this idea and the calculation has come to be known as Weinberg's differential rule (WDR). The keystone of WDR is that DZ twin pairs should be equally likely to be of the same or the opposite sex. Although the probability of a male birth is greater than .5, the reliability of WDR's assumptions has never been conclusively verified or rejected. Let the probability for an opposite-sex (OS) twin maternity be pO , for a same-sex (SS) twin maternity pS and, consequently, the probability for other maternities 1 - pS - pO . The parameter estimates $\\hat p_O$ and $\\hat p_S$ are relative frequencies. Applying WDR, the MZ rate is m = pS - pO and the DZ rate is d = 2pO , but the estimates $\\hat m$ and $\\hat d$ are not relative frequencies. The maximum likelihood estimators $\\hat p_S$ and $\\hat p_O$ are unbiased, efficient, and asymptotically normal. The linear transformations $\\hat m = \\hat p_S - \\hat p_O$ and ${\\skew6\\hat d} = 2\\hat p_O$ are efficient and asymptotically normal. If WDR holds they are also unbiased. For the tests of a set of m and d rates, contingency tables cannot be used. Alternative tests are presented and the models are applied on published data. PMID:24063661

  16. Comparison of the complementary feeding practices between mothers with twins and mothers with singletons

    PubMed Central

    Bentil, Helena Joycelyn; Steiner-Asiedu, Matilda; Lartey, Anna

    2016-01-01

    Introduction Several studies have been done on infant feeding practices but few have focused on twins. The aim of this study was to compare the complementary feeding practices between mothers with twins and mothers with singletons. Methods Mother-infant pairs (50 mother-twin pairs and 50 mother-singleton pairs) with children aged 6 to 23 months were recruited from two public health clinics and communities in Tema and Ashaiman. Information was collected on the background characteristics of the mothers. Recumbent length and weight of the children were measured. Dietary information on the infants was collected using 24 hour recall. The differences between two groups were tested using independent t-student test for continuous variables and chi-square test for categorical variables. Results The minimum dietary diversity (4+ food groups) was met by only 32% of the twins and 40% of the singletons, and 28% of the twins and 38% of the singletons met the requirement for minimum acceptable diet (minimum dietary diversity and the minimum meal frequency). Minimum meal frequency was met by 78% of the twins and 76% of the singletons. There were no significant differences between the two groups of infants. Prevalence of undernutrition was not significantly different among the two groups (twins versus singletons: underweight-26% versus 24%, stunting-20% versus 24% and wasting-14% versus 10%. Conclusion Complementary feeding practices were suboptimal in both groups of mothers requiring interventions to improve infant feeding practices. PMID:27642393

  17. Comparison of the complementary feeding practices between mothers with twins and mothers with singletons

    PubMed Central

    Bentil, Helena Joycelyn; Steiner-Asiedu, Matilda; Lartey, Anna

    2016-01-01

    Introduction Several studies have been done on infant feeding practices but few have focused on twins. The aim of this study was to compare the complementary feeding practices between mothers with twins and mothers with singletons. Methods Mother-infant pairs (50 mother-twin pairs and 50 mother-singleton pairs) with children aged 6 to 23 months were recruited from two public health clinics and communities in Tema and Ashaiman. Information was collected on the background characteristics of the mothers. Recumbent length and weight of the children were measured. Dietary information on the infants was collected using 24 hour recall. The differences between two groups were tested using independent t-student test for continuous variables and chi-square test for categorical variables. Results The minimum dietary diversity (4+ food groups) was met by only 32% of the twins and 40% of the singletons, and 28% of the twins and 38% of the singletons met the requirement for minimum acceptable diet (minimum dietary diversity and the minimum meal frequency). Minimum meal frequency was met by 78% of the twins and 76% of the singletons. There were no significant differences between the two groups of infants. Prevalence of undernutrition was not significantly different among the two groups (twins versus singletons: underweight-26% versus 24%, stunting-20% versus 24% and wasting-14% versus 10%. Conclusion Complementary feeding practices were suboptimal in both groups of mothers requiring interventions to improve infant feeding practices.

  18. Ecosensitivity and genetic polymorphism of somatic traits in the perinatal development of twins.

    PubMed

    Waszak, Małgorzata; Cieślik, Krystyna; Skrzypczak-Zielińska, Marzena; Szalata, Marlena; Wielgus, Karolina; Kempiak, Joanna; Bręborowicz, Grzegorz; Słomski, Ryszard

    2016-04-01

    In view of criticism regarding the usefulness of heritability coefficients, the aim of this study was to analyze separately the information on genetic and environmental variability. Such an approach, based on the normalization of trait's variability for its value, is determined by the coefficients of genetic polymorphism (Pg) and ecosensitivity (De). The studied material included 1263 twin pairs of both sexes (among them 424 pairs of monozygotic twins and 839 pairs of dizygotic twins) born between the 22nd and 41st week of gestation. Variability of six somatic traits was analyzed. The zygosity of same-sex twins was determined based on the polymorphism of DNA from lymphocytes of the umbilical cord blood, obtained at birth. The coefficients of genetic polymorphism and ecosensitivity for analyzed traits of male and female twins born at various months of gestation were calculated. Our study revealed that a contribution of the genetic component predominated over that of the environmental component in determining the phenotypic variability of somatic traits of newborns from twin pregnancies. The genetically determined phenotypic variability in male twins was greater than in the females. The genetic polymorphism and ecosensitivity of somatic traits were relatively stable during the period of fetal ontogeny analyzed in this study. Only in the case of body weight, a slight increase in the genetic contribution of polygenes to the phenotypic variance could be observed with gestational age, along with a slight decrease in the influence of environmental factors.

  19. Epidemiology of twinning in the National Birth Defects Prevention Study, 1997–2007

    PubMed Central

    Dawson, April L.; Tinker, Sarah C.; Jamieson, Denise J.; Hobbs, Charlotte A.; Rasmussen, Sonja A.; Reefhuis, Jennita

    2015-01-01

    Background Our objective was to evaluate associations between twinning and maternal demographic factors and periconceptional exposures among infants with and without orofacial clefts. Methods We used data from the National Birth Defects Prevention Study; 228 twins and 8,242 singletons without birth defects (controls), and 117 twins and 2,859 singletons with orofacial clefts, born 1997–2007, were included in the analyses. Because of the occurrence of twinning due to the use of assisted reproductive technologies, logistic regression models were computed to estimate odds ratios (OR) and 95% confidence intervals (CIs) for each exposure, stratified by fertility treatment use. To evaluate factors by zygosity, we used sex-pairing data and a simulation approach to estimate the zygosity of like-sex twin pairs for unassisted conceptions. Results Among control mothers who did not use fertility treatments, predictors of twinning included non-Hispanic black maternal race (adjusted OR: 1.6, 95% CI: 1.0–2.4), and tobacco smoking (1.6, 1.1–2.4). Among control mothers who used fertility treatments, older maternal age, higher income, and state of residence were associated with twinning. Associations were generally stronger among mothers of dizygotic (estimated) twins than monozygotic (estimated) twins. Results for mothers of infants with isolated orofacial clefts were similar to those of controls. Conclusion We observed an increased twinning frequency with increasing maternal age, but factors such as maternal race/ethnicity and socioeconomic status may also contribute. Among women receiving fertility treatments, factors associated with twinning suggested a relation with treatment specifics (e.g., treatment type and number of embryos implanted) and availability of insurance coverage. PMID:25359509

  20. The Nature of Covariation between Autistic Traits and Clumsiness: A Twin Study in a General Population Sample

    ERIC Educational Resources Information Center

    Moruzzi, Sara; Ogliari, Anna; Ronald, Angelica; Happe, Francesca; Battaglia, Marco

    2011-01-01

    While social impairment, difficulties with communication, and restricted repetitive behaviors are central features of Autism Spectrum Disorders, physical clumsiness is a commonly co-occurring feature. In a sample of 398 twin pairs (aged 8-17 years) from the Italian Twin Registry we investigated the nature of the co-variation between a psychometric…

  1. Birth Weight and Attention-Deficit/Hyperactivity Symptoms in Childhood and Early Adolescence: A Prospective Swedish Twin Study

    ERIC Educational Resources Information Center

    Hultman, Christina M.; Torrang, Anna; Tuvblad, Catherine; Cnattingius, Sven; Larsson, Jan-Olov; Lichtenstein, Paul

    2007-01-01

    Objective: To determine whether low birth weight increases the risk of attention-deficit/hyperactivity disorder (ADHD) in childhood and early adolescence. Method: In a population-based sample of 1,480 twin pairs born in the period 1985-1986 ascertained from the Swedish Twin Registry, birth weight was collected prospectively through the Medical…

  2. Math Fluency Is Etiologically Distinct from Untimed Math Performance, Decoding Fluency, and Untimed Reading Performance: Evidence from a Twin Study

    ERIC Educational Resources Information Center

    Petrill, Stephen; Logan, Jessica; Hart, Sara; Vincent, Pamela; Thompson, Lee; Kovas, Yulia; Plomin, Robert

    2012-01-01

    The authors examined whether math fluency was independent from untimed math and from reading using 314 pairs of school-aged twins drawn from the Western Reserve Reading and Math Projects. Twins were assessed through a 90-min home visit at approximately age 10 and were reassessed in their homes approximately 1 year later. Results suggested that the…

  3. Does Learning to Read Improve Intelligence? A Longitudinal Multivariate Analysis in Identical Twins from Age 7 to 16

    ERIC Educational Resources Information Center

    Ritchie, Stuart J.; Bates, Timothy C.; Plomin, Robert

    2015-01-01

    Evidence from twin studies points to substantial environmental influences on intelligence, but the specifics of this influence are unclear. This study examined one developmental process that potentially causes intelligence differences: learning to read. In 1,890 twin pairs tested at 7, 9, 10, 12, and 16 years, a cross-lagged…

  4. Inspection Time and Cognitive Abilities in Twins Aged 7 to 17 Years: Age-Related Changes, Heritability and Genetic Covariance

    ERIC Educational Resources Information Center

    Edmonds, Caroline J.; Isaacs, Elizabeth B.; Visscher, Peter M.; Rogers, Mary; Lanigan, Julie; Singhal, Atul; Lucas, Alan; Gringras, Paul; Denton, Jane; Deary, Ian J.

    2008-01-01

    We studied the age-related differences in inspection time and multiple cognitive domains in a group of monozygotic (MZ) and dizygotic (DZ) twins aged 7 to 17 years. Data from 111 twin pairs and 19 singleton siblings were included. We found clear age-related trends towards more efficient visual information processing in older participants. There…

  5. Difference Between Identical and Fraternal Twins

    MedlinePlus

    ... egg divides into 2. If twins are a boy and a girl, clearly they are fraternal twins, as they do ... XY chromosomes and a girl has XX chromosomes. Girl-boy twins occur when one X egg is fertilized ...

  6. A Multivariate Twin Study of the DSM-IV Criteria for Antisocial Personality Disorder

    PubMed Central

    Kendler, Kenneth S.; Aggen, Steven H.; Patrick, Christopher J.

    2012-01-01

    BACKGROUND Many assessment instruments for psychopathy are multidimensional, suggesting that distinguishable factors are needed to effectively capture variation in this personality domain. However, no prior study has examined the factor structure of the DSM-IV criteria for antisocial personality disorder (ASPD). METHODS Self-report questionnaire items reflecting all A criteria for DSM-IV ASPD were available from 4,291 twins (including both members of 1,647 pairs) from the Virginia Adult Study of Psychiatric and Substance Use Disorders. Exploratory factor analysis and twin model fitting were performed using, respectively, Mplus and Mx. RESULTS Phenotypic factor analysis produced evidence for 2 correlated factors: aggressive-disregard and disinhibition. The best-fitting multivariate twin model included two genetic and one unique environmental common factor, along with criteria-specific genetic and environmental effects. The two genetic factors closely resembled the phenotypic factors and varied in their prediction of a range of relevant criterion variables. Scores on the genetic aggressive-disregard factor score were more strongly associated with risk for conduct disorder, early and heavy alcohol use, and low educational status, whereas scores on the genetic disinhibition factor score were more strongly associated with younger age, novelty seeking, and major depression. CONCLUSION From a genetic perspective, the DSM-IV criteria for ASPD do not reflect a single dimension of liability but rather are influenced by two dimensions of genetic risk reflecting aggressive-disregard and disinhibition. The phenotypic structure of the ASPD criteria results largely from genetic and not from environmental influences. PMID:21762879

  7. A Demonstration of the Generalizability of Twin-based Research on Antisocial Behavior

    PubMed Central

    Barnes, J.C.; Boutwell, Brian B.

    2013-01-01

    Researchers typically analyze samples of twin pairs in order to decompose trait variance into genetic and environmental components. This methodological technique, referred to as twin-based research, rests on several assumptions that must be satisfied in order to produce unbiased results. While research has analyzed the tenability of certain assumptions such as equal environments, less attention has been given to whether results gleaned from samples of twins generalize to the broader population of non-twins. The current study analyzed data drawn from the National Longitudinal Study of Adolescent Health and findings suggested twins do not systematically differ from the general population of non-twins on many measures of behavior and development. Furthermore, the effects of specific covariates on measures of antisocial behavior did not appear to differ across twin status. In sum, evidence concerning the etiology of antisocial behavior (e.g., heritability estimates) gleaned from twin-based research is likely to generalize to the non-twin population. PMID:23274656

  8. Chromosome 22q11.2 microdeletion in monozygotic twins with discordant phenotype and deletion size.

    PubMed

    Halder, Ashutosh; Jain, Manish; Chaudhary, Isha; Varma, Binuja

    2012-01-01

    We report on a pair of male monozygotic twins with 22q11.2 microdeletion, discordant phenotype and discordant deletion size. The second twin had findings suggestive of DiGeorge syndrome, while the first twin had milder anomalies without any cardiac malformation. The second twin had presented with intractable convulsion, cyanosis and cardiovascular failure in the fourth week of life and expired on the sixth week of life, whereas the first twin had some characteristic facial appearance with developmental delay but no other signs of the 22q11.2 microdeletion syndrome including cardiovascular malformation. The fluorescence in situ hybridization (FISH) analysis had shown a microdeletion on the chromosome 22q11.2 in both twins. The interphase FISH did not find any evidence for the mosaicism. The genomic DNA microarray analysis, using HumanCytoSNP-12 BeadChip (Illumina), was identical between the twins except different size of deletion of 22q11.2. The zygosity using HumanCytoSNP-12 BeadChip (Illumina) microarray analysis suggested monozygosity. This observation indicates that altered size of the deletion may be the underlying etiology for the discordance in phenotype in monozygotic twins. We think early post zygotic events (mitotic non-allelic homologous recombination) could have been played a role in the alteration of 22q11.2 deletion size and, thus phenotypic variability in the monozygotic twins. PMID:22413934

  9. A deletion mutation in GDF9 in sisters with spontaneous DZ twins.

    PubMed

    Montgomery, Grant W; Zhao, Zhen Zhen; Marsh, Anna J; Mayne, Renee; Treloar, Susan A; James, Michael; Martin, Nicholas G; Boomsma, Dorret I; Duffy, David L

    2004-12-01

    A loss of function mutation in growth differentiation factor 9 (GDF9) in sheep causes increased ovulation rate and infertility in a dosage-sensitive manner. Spontaneous dizygotic (DZ) twinning in the human is under genetic control and women with a history of DZ twinning have an increased incidence of multiple follicle growth and multiple ovulation. We sequenced the GDF9 coding region in DNA samples from 20 women with DZ twins and identified a four-base pair deletion in GDF9 in two sisters with twins from one family. We screened a further 429 families and did not find the loss of function mutation in any other families. We genotyped eight single nucleotide polymorphisms across the GDF9 locus in 379 families with two sisters who have both given birth to spontaneous DZ twins (1527 individuals) and 226 triad families with mothers of twins and their parents (723 individuals). Using case control analysis and the transmission disequilibrium test we found no evidence for association between common variants in GDF9 and twinning in the families. We conclude that rare mutations in GDF9 may influence twinning, but twinning frequency is not associated with common variation in GDF9.

  10. Genetic influence on contrast sensitivity in middle-aged male twins.

    PubMed

    Cronin-Golomb, Alice; Panizzon, Matthew S; Lyons, Michael J; Franz, Carol E; Grant, Michael D; Jacobson, Kristen C; Eisen, Seth A; Laudate, Thomas M; Kremen, William S

    2007-07-01

    Contrast sensitivity is strongly associated with daily functioning among older adults, but the genetic and environmental contributions to this ability are unknown. Using the classical twin method, we addressed this issue by examining contrast sensitivity at five spatial frequencies (1.5-18 cycles per degree) in 718 middle-aged male twins from the Vietnam Era Twin Study of Aging (VETSA). Heritability estimates were modest (14-38%), whereas individual-specific environmental influences accounted for 62-86% of the variance. Identifying the types of individual-specific events that impact contrast sensitivity may suggest interventions to modulate this ability and thereby improve overall quality of life as adults age.

  11. Protective and Harmful Effects of Physical Activity for Low Back Pain: A Protocol for the AUstralian Twin BACK Pain (AUTBACK) Feasibility Study.

    PubMed

    Pinheiro, Marina B; Ferreira, Manuela L; Refshauge, Kathryn; Hopper, John; Maher, Christopher G; Hartvigsen, Jan; Koes, Bart; Hübscher, Markus; Ferreira, Paulo H

    2016-10-01

    Low back pain (LBP) is a major health problem globally, but approaches to prevention are not yet clearly identified because modifiable risk factors are not well established. Although physical activity is one promising modifiable risk factor, it is still not known what types and doses of physical activity are protective or harmful for LBP. The aim of this study is to establish the feasibility of a definitive cohort study that will investigate the effects of different types and doses of physical activity on the risk of developing recurrent LBP while accounting for genetic factors. This will be a pilot longitudinal twin study and twins will be recruited from the Australian Twin Registry, and will be followed over 1 year. Thirty adult complete twin pairs with a history of LBP, but symptom free at recruitment, will be included. Data on physical activity (predictor) will be collected using four questionnaires and an objective measure (accelerometer) at baseline and at 6-month follow-up. Twins will also complete an additional physical activity questionnaire monthly. Data on LBP (outcome) will be collected at baseline and weekly. Data will be collected using short message service (SMS) and email. We will keep records of the recruitment rate, follow-up rate, and completeness of data. Barriers to completing the study will be investigated. The results of this study will inform the design and implementation of a future definitive study, which will help to clarify the effects of different types and doses of physical activity on the risk of developing recurrent LBP. PMID:27633124

  12. Marital Conflict and Conduct Problems in Children of Twins

    PubMed Central

    Harden, K. Paige; Turkheimer, Eric; Emery, Robert E.; D’Onofrio, Brian M.; Slutske, Wendy S.; Heath, Andrew C.; Martin, Nicholas G.

    2010-01-01

    The Children-of-Twins design was used to test whether associations between marital conflict frequency and conduct problems can be replicated within the children of discordant twin pairs. A sample of 2,051 children (age 14–39 years) of 1,045 twins was used to estimate the genetic and environmental influences on marital conflict and determine whether genetic or environmental selection processes underlie the observed association between marital conflict and conduct problems. Results indicate that genetic and nonshared environmental factors influence the risk of marital conflict. Furthermore, genetic influences mediated the association between marital conflict frequency and conduct problems. These results highlight the need for quasiexperimental designs in investigations of intergenerational associations. PMID:17328690

  13. Mitochondrial DNA Variation and Heteroplasmy in Monozygotic Twins Clinically Discordant for Multiple Sclerosis.

    PubMed

    Souren, Nicole Y P; Gerdes, Lisa A; Kümpfel, Tania; Lutsik, Pavlo; Klopstock, Thomas; Hohlfeld, Reinhard; Walter, Jörn

    2016-08-01

    We examined the debated link between mitochondrial DNA (mtDNA) variation and multiple sclerosis (MS) using 49 monozygotic (MZ) twin pairs clinically discordant for MS, which enables to associate de novo mtDNA variants, skewed heteroplasmy, and mtDNA copy number with MS manifestation. Ultra-deep sequencing of blood-derived mtDNA revealed 25 heteroplasmic variants with potentially pathogenic features in 18 pairs. All variants were pair-specific and had low and/or similar heteroplasmy levels in both cotwins. In one pair, a confirmed pathogenic variant (m.11778G>A, heteroplasmy ∼50%) associated with Leber hereditary optic neuropathy was detected. Detailed diagnostic investigation revealed subclinical MS signs in the prior nondiseased cotwin. Moreover, neither mtDNA deletions nor copy-number variations were involved. Furthermore, the majority of heteroplasmic variants were shared among MZ twins and exhibited more similar heteroplasmy levels in the same tissue of MZ twins as compared with different tissues of the same individual. Heteroplasmy levels were also more similar within MZ twins compared with nonidentical siblings. Our analysis excludes mtDNA variation as a major driver of the discordant clinical manifestation of MS in MZ twins, and provides valuable insights into the occurrence and distribution of heteroplasmic variants within MZ twins and nonidentical siblings, and across different tissues. PMID:27119776

  14. Twin Town in South Brazil: a Nazi's experiment or a genetic founder effect?

    PubMed

    Tagliani-Ribeiro, Alice; Oliveira, Mariana; Sassi, Adriana K; Rodrigues, Maira R; Zagonel-Oliveira, Marcelo; Steinman, Gary; Matte, Ursula; Fagundes, Nelson J R; Schuler-Faccini, Lavinia

    2011-01-01

    Cândido Godói (CG) is a small municipality in South Brazil with approximately 6,000 inhabitants. It is known as the "Twins' Town" due to its high rate of twin births. Recently it was claimed that such high frequency of twinning would be connected to experiments performed by the German Nazi doctor Joseph Mengele. It is known, however, that this town was founded by a small number of families and therefore a genetic founder effect may represent an alternatively explanation for the high twinning prevalence in CG. In this study, we tested specific predictions of the "Nazi's experiment" and of the "founder effect" hypotheses. We surveyed a total of 6,262 baptism records from 1959-2008 in CG catholic churches, and identified 91 twin pairs and one triplet. Contrary to the "Nazi's experiment hypothesis", there is no spurt in twinning between the years (1964-1968) when Mengele allegedly was in CG (P = 0.482). Moreover, there is no temporal trend for a declining rate of twinning since the 1960s (P = 0.351), and no difference in twinning among CG districts considering two different periods: 1927-1958 and 1959-2008 (P = 0.638). On the other hand, the "founder effect hypothesis" is supported by an isonymy analysis that shows that women who gave birth to twins have a higher inbreeding coefficient when compared to women who never had twins (0.0148, 0.0081, respectively, P = 0.019). In summary, our results show no evidence for the "Nazi's experiment hypothesis" and strongly suggest that the "founder effect hypothesis" is a much more likely alternative for explaining the high prevalence of twinning in CG. If this hypothesis is correct, then this community represents a valuable population where genetic factors linked to twinning may be identified.

  15. Intrapair Similarity of Computer Self-Efficacy in Turkish Adolescent Twins

    ERIC Educational Resources Information Center

    Deryakulu, Deniz; Mcilroy, David; Ursavas, Ömer Faruk; Çaliskan, Erkan

    2016-01-01

    The purpose of this study is to investigate genetic and environmental influences on computer self-efficacy. A total of 165 Turkish twin-pairs participated in the study. Participants' mean age was 12.45 (SD = 1.82). The results of paired t-test comparisons showed no significant differences in monozygotic, and both same-sex and opposite-sex…

  16. Is there a genetic basis for Fuchs' heterochromic uveitis? Discordance in monozygotic twins.

    PubMed Central

    Jones, N P; Read, A P

    1992-01-01

    One pair, and probably two pairs, of monozygotic twins are reported with discordance for Fuchs' heterochromic uveitis (FHU). Regular Mendelian inheritance of this disease is now proved to be impossible. The heritability of FHU is low and may be zero. The possibility of any genetic predisposition to the disease and its association with 'simple' heterochromia are discussed. Images PMID:1739686

  17. Twin Legacies: Victor and Vincent McKusick/Twin Studies: Twinning Rates I; Twinning Rates II; MZ Twin Discordance for Russell-Silver Syndrome; Twins' Language Skills/Headlines: Babies Born to Identical Twin Couples; Identity Exchange; Death of Princess Ashraf (Twin); Yahoo CEO Delivers Identical Twins.

    PubMed

    Segal, Nancy L

    2016-04-01

    The lives of the illustrious monozygotic (MZ) twins, Victor A. and Vincent L. McKusick, are described. Victor earned the distinction as the 'Father of Medical Genetics', while Vincent was a legendary Chief Justice of the Maine Supreme Court. This dual biographical account is followed by two timely reports of twinning rates, a study of MZ twin discordance for Russell-Silver Syndrome (RSS) and a study of twins' language skills. Twin stories in the news include babies born to identical twin couples, a case of switched identity, the death of Princess Ashraf (Twin) and a new mother of twins who is also Yahoo's CEO. PMID:26934824

  18. Twin Legacies: Victor and Vincent McKusick/Twin Studies: Twinning Rates I; Twinning Rates II; MZ Twin Discordance for Russell-Silver Syndrome; Twins' Language Skills/Headlines: Babies Born to Identical Twin Couples; Identity Exchange; Death of Princess Ashraf (Twin); Yahoo CEO Delivers Identical Twins.

    PubMed

    Segal, Nancy L

    2016-04-01

    The lives of the illustrious monozygotic (MZ) twins, Victor A. and Vincent L. McKusick, are described. Victor earned the distinction as the 'Father of Medical Genetics', while Vincent was a legendary Chief Justice of the Maine Supreme Court. This dual biographical account is followed by two timely reports of twinning rates, a study of MZ twin discordance for Russell-Silver Syndrome (RSS) and a study of twins' language skills. Twin stories in the news include babies born to identical twin couples, a case of switched identity, the death of Princess Ashraf (Twin) and a new mother of twins who is also Yahoo's CEO.

  19. Confronting Twin Paradox Acceleration

    NASA Astrophysics Data System (ADS)

    Murphy, Thomas W.

    2016-05-01

    The resolution to the classic twin paradox in special relativity rests on the asymmetry of acceleration. Yet most students are not exposed to a satisfactory analysis of what exactly happens during the acceleration phase that results in the nonaccelerated observer's more rapid aging. The simple treatment presented here offers both graphical and quantitative solutions to the problem, leading to the correct result that the acceleration-induced age gap is 2Lβ years when the one-way distance L is expressed in light-years and velocity β ≡v/c .

  20. Holographic twin Higgs model.

    PubMed

    Geller, Michael; Telem, Ofri

    2015-05-15

    We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.

  1. Holographic twin Higgs model.

    PubMed

    Geller, Michael; Telem, Ofri

    2015-05-15

    We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider. PMID:26024160

  2. The role of the placenta in variability of fetal exposure to cocaine and cannabinoids: a twin study.

    PubMed

    Boskovic, R; Klein, J; Woodland, C; Karaskov, T; Koren, G

    2001-11-01

    There is wide variability in the reported adverse fetal effects of cocaine and cannabinoids. The causes of this variability are largely unknown. We hypothesized that variability in placental handling of drugs affect fetal exposure. We used twin pregnancies as a paradigm to address the role of the placenta in this variability. We analyzed hair or meconium samples taken from dizygotic and monozygotic twins exposed in utero to illicit drugs. Out of 12 pairs, 5 had negative levels in both twins, and seven pairs of twins had chemical evidence of fetal exposure to cocaine (n = 5) or cannabinoids (n = 2). The one known monozygotic pair of twins had almost identical levels of cocaine. In contrast, the six dizygotic pairs had large disparities in either cocaine or cannabinoid concentrations. In three of these six dizygotic pairs, levels of cocaine (n = 2) or canabinoids (n = 1) were undetectable in one twin while positive in the other. Given that twins are theoretically exposed to similar maternal drug levels, our findings suggest that the placenta may have a major role in modulating the amounts of drug reaching the fetus.

  3. Copy number detection in discordant monozygotic twins of Congenital Diaphragmatic Hernia (CDH) and Esophageal Atresia (EA) cohorts.

    PubMed

    Veenma, Danielle; Brosens, Erwin; de Jong, Elisabeth; van de Ven, Cees; Meeussen, Connie; Cohen-Overbeek, Titia; Boter, Marjan; Eussen, Hubertus; Douben, Hannie; Tibboel, Dick; de Klein, Annelies

    2012-03-01

    The occurrence of phenotypic differences between monozygotic (MZ) twins is commonly attributed to environmental factors, assuming that MZ twins have a complete identical genetic make-up. Yet, recently several lines of evidence showed that both genetic and epigenetic factors could have a role in phenotypic discordance after all. A high occurrence of copy number variation (CNV) differences was observed within MZ twin pairs discordant for Parkinson's disease, thereby stressing on the importance of post-zygotic mutations as disease-predisposing events. In this study, the prevalence of discrepant CNVs was analyzed in discordant MZ twins of the Esophageal Atresia (EA) and Congenital Diaphragmatic Hernia (CDH) cohort in the Netherlands. Blood-derived DNA from 11 pairs (7 EA and 4 CDH) was screened using high-resolution SNP arrays. Results showed an identical copy number profile in each twin pair. Mosaic chromosome gain or losses could not be detected either with a detection threshold of 20%. Some of the germ-line structural events demonstrated in five out of eleven twin pairs could function as a susceptible genetic background. For example, the 177-Kb loss of chromosome 10q26 in CDH pair-3 harbors the TCF7L2 gene (Tcf4 protein), which is implicated in the regulation of muscle fiber type development and maturation. In conclusion, discrepant CNVs are not a common cause of twin discordancy in these investigated congenital anomaly cohorts. PMID:22071887

  4. Transformation: From Twin to Individual

    ERIC Educational Resources Information Center

    Magagna, Jeanne

    2007-01-01

    This article explores some of the complexities of psychotherapy with an identical twin. The difficulty of developing in psychotherapy while so much of what is oneself is located in the other twin will also be explored. The use of the countertransference as a therapeutic method will be considered as the young person develops her unique, separate…

  5. [Similarity of monozygotic twins regarding vocal performance and acoustic markers and possible clinical significance].

    PubMed

    Fuchs, M; Oeken, J; Hotopp, T; Täschner, R; Hentschel, B; Behrendt, W

    2000-06-01

    Auditory similarities in voices of monozygotic twins have already been described in the literature. However, is there a clinical relevance? Thus, the present study was designed to identify parameters of vocal performance and acoustic features which are significantly more similar in monozygotic twins than in non-related persons. In our hypothesis, comparable prerequisites for an increased vocal load in a profession or in an artistic education of the voice could be due to these similarities. We compared intra-pair differences with data from a control group. Moreover, we examined the correlation of intra-pair differences with the age of the monozygotic twins. A greater difference in older twin pairs than in younger pairs could show the effect of an exogene influence. In addition to the few phoniatric studies in twins in the literature, we used current methods for acoustic analysis. We examined seven parameters of vocal performance and three acoustic features in 31 monozygotic twin pairs (median age 36 years, range 18-75 years) and compared them with 30 control group pairs, which consisted of non-related persons of the same age and sex, newly combined from the group of monozygotic twins ("statistical twins"). We found significant differences in seven of ten parameters (vocal range, highest and lowest vocal fundamental frequency, fundamental speaking frequency, maximum voice intensity, number of partials, vibrato of intensity; U-test by Mann-Whitney). No correlation of the differences of the identical twins with age was found in the examined parameters. The voices of identical twins are significantly more similar than those of non-related persons regarding the above mentioned features. Thus, the suitability of the voices of monozygotic twins for professions with a high demand on voice is comparable. Results of the group comparison correlate largely with the literature. The missing correlation with age could be due to the fact that the environmental effects were not

  6. Atopic diseases in twins born after assisted reproduction.

    PubMed

    Jäderberg, Ida; Thomsen, Simon F; Kyvik, Kirsten O; Skytthe, Axel; Backer, Vibeke

    2012-03-01

    We examined the risk of atopic diseases in twins born after assisted reproduction. Data on atopic diseases and assisted reproduction in 9694 twin pairs, 3-20 years of age, from the Danish Twin Registry were collected via multidisciplinary questionnaires. The risk of atopic diseases in twins born after assisted reproduction was compared with the risk in twins born after spontaneous conception using logistic regression and variance components analysis. Children born after assisted reproduction did not have a different risk of atopic outcomes (adjusted odds ratios [95% confidence intervals] for asthma: 0.95 [0.85, 1.07], P = 0.403; hay fever: 1.01 [0.86, 1.18], P = 0.918; and atopic dermatitis: 1.02 [0.81, 1.11], P = 0.773 respectively) compared with children born after spontaneous conception. Assisted reproduction did not modify the heritability of atopic diseases. This study does not support an association between assisted reproduction and development of atopic diseases. This result must be confirmed in subsequent studies, preferably of singleton populations. PMID:22324500

  7. Causal Inference and Observational Research: The Utility of Twins

    PubMed Central

    McGue, Matt; Osler, Merete; Christensen, Kaare

    2011-01-01

    Valid causal inference is central to progress in theoretical and applied psychology. Although the randomized experiment is widely considered the gold standard for determining whether a given exposure increases the likelihood of some specified outcome, experiments are not always feasible and in some cases can result in biased estimates of causal effects. Alternatively, standard observational approaches are limited by the possibility of confounding, reverse causation, and the nonrandom distribution of exposure (i.e., selection). We describe the counterfactual model of causation and apply it to the challenges of causal inference in observational research, with a particular focus on aging. We argue that the study of twin pairs discordant on exposure, and in particular discordant monozygotic twins, provides a useful analog to the idealized counterfactual design. A review of discordant-twin studies in aging reveals that they are consistent with, but do not unambiguously establish, a causal effect of lifestyle factors on important late-life outcomes. Nonetheless, the existing studies are few in number and have clear limitations that have not always been considered in interpreting their results. It is concluded that twin researchers could make greater use of the discordant-twin design as one approach to strengthen causal inferences in observational research. PMID:21593989

  8. Developmental timing of mutations revealed by whole-genome sequencing of twins with acute lymphoblastic leukemia.

    PubMed

    Ma, Yussanne; Dobbins, Sara E; Sherborne, Amy L; Chubb, Daniel; Galbiati, Marta; Cazzaniga, Giovanni; Micalizzi, Concetta; Tearle, Rick; Lloyd, Amy L; Hain, Richard; Greaves, Mel; Houlston, Richard S

    2013-04-30

    Acute lymphoblastic leukemia (ALL) is the major pediatric cancer. At diagnosis, the developmental timing of mutations contributing critically to clonal diversification and selection can be buried in the leukemia's covert natural history. Concordance of ALL in monozygotic, monochorionic twins is a consequence of intraplacental spread of an initiated preleukemic clone. Studying monozygotic twins with ALL provides a unique means of uncovering the timeline of mutations contributing to clonal evolution, pre- and postnatally. We sequenced the whole genomes of leukemic cells from two twin pairs with ALL to comprehensively characterize acquired somatic mutations in ALL, elucidating the developmental timing of all genetic lesions. Shared, prenatal, coding-region single-nucleotide variants were limited to the putative initiating lesions. All other nonsynonymous single-nucleotide variants were distinct between tumors and, therefore, secondary and postnatal. These changes occurred in a background of noncoding mutational changes that were almost entirely discordant in twin pairs and likely passenger mutations acquired during leukemic cell proliferation. PMID:23569245

  9. Exposure to organic solvents and neuropsychological dysfunction: a study on monozygotic twins.

    PubMed Central

    Hänninen, H; Antti-Poika, M; Juntunen, J; Koskenvuo, M

    1991-01-01

    Twenty one monozygotic twins exposed to organic solvents were compared with their non-exposed cotwins by performance in psychological tests. A further 28 monozygotic twin pairs were examined as a reference group. The study used 11 tests, 10 of which had shown an effect in previous studies on the results of exposure to solvents. Paired comparisons of the test scores showed the exposed twins to have lower performance in associative learning, digit span, and block design. These results agree with two previous studies that used a similar set of tests. Contrary to some other studies, psychomotor speed was not affected, but the results indicated a marginal effect on the control of hand movements. Further comparison of subgroups with a low and a high exposure showed the prevalence of subtle neuropsychological dysfunction to be greater among the more exposed twins. PMID:1993155

  10. Effect of local stress fields on twin characteristics in HCP metals

    DOE PAGES

    Arul Kumar, M.; Beyerlein, Irene Jane; Tomé, Carlos N.

    2016-06-23

    Here we study the effect of nearest neighboring grains on the propensity for {1012} twin growth in Mg and Zr. Twin lamellae lying within one grain flanked by two neighboring grains with several orientations are considered. The fields of resolved shear stress on the twin system are calculated in the multicrystal using a three-dimensional full-field crystal plasticity Fast Fourier Transform approach. The calculations were carried out for Mg and Zr using slip threshold stresses corresponding to 300K and 76K, respectively, where twin activity is important. We show that the neighboring grain constraint tends to oppose further growth and that themore » critical applied stress needed to overcome this resistance depends on neighboring grain orientation, more strongly in Zr than in Mg. We also present results for a pair of adjacent and parallel twins at various spacings. It is found that their paired interaction increases the resistive forces for twin growth above that for an isolated twin. The critical spacing above which this enhanced resistance is removed is smaller for Zr than Mg. Our analysis reveals that these two disparate responses of Zr and Mg are both a consequence of the fact that Zr is elastically and plastically more anisotropic than Mg. Additional calculations carried out on Ti support this conclusion. Finally, these findings can help explain why, for the same grain size, more twins per grain form in Zr than in Mg, twins in Zr tend to be thinner than those in Mg, and the relationship between the thickness of the twin and its Schmid factor in Zr is not as strong as in Mg.« less

  11. A multivariate twin analysis of within-family environmental influences in infants' social responsiveness.

    PubMed

    Rowe, D C; Plomin, R

    1979-11-01

    Observational measures of social responsiveness were obtained for twin infants. The structure of within-family environmental influences was assessed by correlating identical twin pair differences for 13 behaviors in seven social settings. Factor analysis of the difference score matrix yielded one interpretable factor. This factor indicated that within-family environmental influences were not completely random but may exert a systematic effect on social behavior in several situations. PMID:263637

  12. Photon-number statistics of twin beams: Self-consistent measurement, reconstruction, and properties

    SciTech Connect

    Peřina, Jan Jr.; Haderka, Ondřej; Michálek, Václav

    2014-12-04

    A method for the determination of photon-number statistics of twin beams using the joint signal-idler photocount statistics obtained by an iCCD camera is described. It also provides absolute quantum detection efficiency of the camera. Using the measured photocount statistics, quasi-distributions of integrated intensities are obtained. They attain negative values occurring in characteristic strips an a consequence of pairing of photons in twin beams.

  13. Use of a twin dataset to identify AMD-related visual patterns controlled by genetic factors

    NASA Astrophysics Data System (ADS)

    Quellec, Gwénolé; Abràmoff, Michael D.; Russell, Stephen R.

    2010-03-01

    The mapping of genotype to the phenotype of age-related macular degeneration (AMD) is expected to improve the diagnosis and treatment of the disease in a near future. In this study, we focused on the first step to discover this mapping: we identified visual patterns related to AMD which seem to be controlled by genetic factors, without explicitly relating them to the genes. For this purpose, we used a dataset of eye fundus photographs from 74 twin pairs, either monozygotic twins, who have the same genotype, or dizygotic twins, whose genes responsible for AMD are less likely to be identical. If we are able to differentiate monozygotic twins from dizygotic twins, based on a given visual pattern, then this pattern is likely to be controlled by genetic factors. The main visible consequence of AMD is the apparition of drusen between the retinal pigment epithelium and Bruch's membrane. We developed two automated drusen detectors based on the wavelet transform: a shape-based detector for hard drusen, and a texture- and color- based detector for soft drusen. Forty visual features were evaluated at the location of the automatically detected drusen. These features characterize the texture, the shape, the color, the spatial distribution, or the amount of drusen. A distance measure between twin pairs was defined for each visual feature; a smaller distance should be measured between monozygotic twins for visual features controlled by genetic factors. The predictions of several visual features (75.7% accuracy) are comparable or better than the predictions of human experts.

  14. Methylomic analysis of monozygotic twins discordant for autism spectrum disorder and related behavioural traits.

    PubMed

    Wong, C C Y; Meaburn, E L; Ronald, A; Price, T S; Jeffries, A R; Schalkwyk, L C; Plomin, R; Mill, J

    2014-04-01

    Autism spectrum disorder (ASD) defines a group of common, complex neurodevelopmental disorders. Although the aetiology of ASD has a strong genetic component, there is considerable monozygotic (MZ) twin discordance indicating a role for non-genetic factors. Because MZ twins share an identical DNA sequence, disease-discordant MZ twin pairs provide an ideal model for examining the contribution of environmentally driven epigenetic factors in disease. We performed a genome-wide analysis of DNA methylation in a sample of 50 MZ twin pairs (100 individuals) sampled from a representative population cohort that included twins discordant and concordant for ASD, ASD-associated traits and no autistic phenotype. Within-twin and between-group analyses identified numerous differentially methylated regions associated with ASD. In addition, we report significant correlations between DNA methylation and quantitatively measured autistic trait scores across our sample cohort. This study represents the first systematic epigenomic analyses of MZ twins discordant for ASD and implicates a role for altered DNA methylation in autism. PMID:23608919

  15. Heritability estimates of innate immunity: an extended twin study.

    PubMed

    de Craen, A J M; Posthuma, D; Remarque, E J; van den Biggelaar, A H J; Westendorp, R G J; Boomsma, D I

    2005-03-01

    Cytokines are key players in numerous inflammatory processes. Demonstration of a heritable component in the variation of cytokine production would indicate that simultaneous occurrence of conditions might be caused by a heritable inflammatory characteristic. We applied an extended twin study approach to assess heritability estimates of interleukin (IL)-1beta, IL-1ra, IL-10, IL-6, and TNF-alpha production capacity after ex vivo stimulation with lipopolysaccharide. Cytokine production capacity was assessed in 42 monozygotic pairs, 52 dizygotic pairs, one trizygotic triplet, 33 single twins, and 83 additional siblings. Heritability estimates were derived from variance decomposition models using maximum likelihood estimation. For all cytokines, over 50% of the variance was genetically determined. IL-1ra and TNF-alpha had the lowest heritability estimate of 53%. Estimates for IL-6 and IL-10 were 57 and 62%, respectively. IL-1beta had the highest estimate of 86%. We conclude that the production of cytokines is under tight genetic control. PMID:15674372

  16. Twin methodology in epigenetic studies.

    PubMed

    Tan, Qihua; Christiansen, Lene; von Bornemann Hjelmborg, Jacob; Christensen, Kaare

    2015-01-01

    Since the final decades of the last century, twin studies have made a remarkable contribution to the genetics of human complex traits and diseases. With the recent rapid development in modern biotechnology of high-throughput genetic and genomic analyses, twin modelling is expanding from analysis of diseases to molecular phenotypes in functional genomics especially in epigenetics, a thriving field of research that concerns the environmental regulation of gene expression through DNA methylation, histone modification, microRNA and long non-coding RNA expression, etc. The application of the twin method to molecular phenotypes offers new opportunities to study the genetic (nature) and environmental (nurture) contributions to epigenetic regulation of gene activity during developmental, ageing and disease processes. Besides the classical twin model, the case co-twin design using identical twins discordant for a trait or disease is becoming a popular and powerful design for epigenome-wide association study in linking environmental exposure to differential epigenetic regulation and to disease status while controlling for individual genetic make-up. It can be expected that novel uses of twin methods in epigenetic studies are going to help with efficiently unravelling the genetic and environmental basis of epigenomics in human complex diseases. PMID:25568460

  17. Twin Higgs Asymmetric Dark Matter.

    PubMed

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-18

    We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors. PMID:26430985

  18. Twin Higgs Asymmetric Dark Matter.

    PubMed

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-18

    We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.

  19. Twins and Kindergarten Separation: Divergent Beliefs of Principals, Teachers, Parents, and Twins

    ERIC Educational Resources Information Center

    Gordon, Lynn Melby

    2015-01-01

    Should principals enforce mandatory separation of twins in kindergarten? Do school separation beliefs of principals differ from those of teachers, parents of twins, and twins themselves? This survey questioned 131 elementary principals, 54 kindergarten teachers, 201 parents of twins, and 112 twins. A majority of principals (71%) believed that…

  20. The Genetic Relationship between Indentical Twins.

    ERIC Educational Resources Information Center

    Herman, Rosemary

    1984-01-01

    Reviews current research on a woman's chances of bearing twins and the genetic relationship, prenatal competition, and personality similarities between twins. In addition, the nature/nurture controversy is discussed in terms of evidence from studies of identical twins reared apart. Future studies are suggested to discover the ways twinning might…

  1. Best Practices for Twin Placement in School

    ERIC Educational Resources Information Center

    Lacina, Jan

    2012-01-01

    The children's book "Two Is for Twins" celebrates twins and illustrates the many "twos" in a child's world. The uniqueness of twos does not have to mean separate classrooms for twins in child development programs, preschool, or elementary school settings. With recent dramatic increases in the US twin population, how should educators address the…

  2. Twin-singleton differences in cognitive abilities in a sample of Africans in Nigeria.

    PubMed

    Hur, Yoon-Mi; Lynn, Richard

    2013-08-01

    Recent studies comparing cognitive abilities between contemporary twins and singletons in developed countries have suggested that twin deficits in cognitive abilities no longer exist. We examined cognitive abilities in a sample of twins and singletons born recently in Nigeria to determine whether recent findings can be replicated in developing countries. Our sample consisted of 413 pairs of twins and 280 singletons collected from over 45 public schools in Abuja and its neighboring states in Nigeria. The ages of twins and singletons ranged from 9 to 20 years with a mean (SD) of 14.6 years (2.2 years) for twins and 16.1 years (1.8 years) for singletons. Zygosity of the same-sex twins was determined by analysis of 16 deoxyribonucleic acid markers. We asked participants to complete a questionnaire booklet that included Standard Progressive Matrices-Plus Version (SPM+), Mill-Hill Vocabulary Scale (MHV), Family Assets Questionnaire, and demographic questions. The data were corrected for sex and age and then analyzed using maximum likelihood model-fitting analysis. Although twins and singletons were comparable in family social class indicators, singletons did better than twins across all the tests (d = 0.10 to 0.35). The average of d for SPM+ total [0.32; equivalent to 4.8 Intelligence Quotient (IQ) points] and d for MHV (0.24; equivalent to 3.6 IQ points) was 0.28 (equivalent to 4.2 IQ points), similar to the twin-singleton gap found in old cohorts in developed countries. We speculate that malnutrition, poor health, and educational systems in Nigeria may explain the persistence of twin deficits in cognitive abilities found in our sample. PMID:23835288

  3. DNA methylation profiles in type 1 diabetes twins point to strong epigenetic effects on etiology.

    PubMed

    Stefan, Mihaela; Zhang, Weijia; Concepcion, Erlinda; Yi, Zhengzi; Tomer, Yaron

    2014-05-01

    Type 1 diabetes (T1D) shows ∼40% concordance rate in monozygotic twins (MZ) suggesting a role for environmental factors and/or epigenetic modifications in the etiology of the disease. The aim of our study was to dissect the contribution of epigenetic factors, particularly, DNA methylation (DNAm), to the incomplete penetrance of T1D. We performed DNAm profiling in lymphocyte cell lines from 3 monozygotic (MZ) twin pairs discordant for T1D and 6 MZ twin pairs concordant for the disease using HumanMethylation27 BeadChip. This assay assesses the methylation state of 27,578 CpG sites, mostly located within proximal promoter regions. We identified 88 CpG sites displaying significant methylation changes in all T1D-discordant MZ twin pairs. Functional annotation of the genes with distinct CpG methylation profiles in T1D samples showed differential DNAm of immune response and defense response pathways between affected and unaffected twins. Integration of DNAm data with GWAS data mapped several known T1D associated genes, HLA, INS, IL-2RB, CD226, which showed significant differences in DNAm between affected and unaffected of twins. Our findings suggest that abnormalities of DNA methylation patterns, known to regulate gene transcription, may be involved in the pathogenesis of T1D. PMID:24210274

  4. Inheritance of dermatoglyphic asymmetry and diversity traits in twins based on factor: variance decomposition analysis.

    PubMed

    Karmakar, Bibha; Malkin, Ida; Kobyliansky, Eugene

    2013-06-01

    Dermatoglyphic asymmetry and diversity traits from a large number of twins (MZ and DZ) were analyzed based on principal factors to evaluate genetic effects and common familial environmental influences on twin data by the use of maximum likelihood-based Variance decomposition analysis. Sample consists of monozygotic (MZ) twins of two sexes (102 male pairs and 138 female pairs) and 120 pairs of dizygotic (DZ) female twins. All asymmetry (DA and FA) and diversity of dermatoglyphic traits were clearly separated into factors. These are perfectly corroborated with the earlier studies in different ethnic populations, which indicate a common biological validity perhaps exists of the underlying component structures of dermatoglyphic characters. Our heritability result in twins clearly showed that DA_F2 is inherited mostly in dominant type (28.0%) and FA_F1 is additive (60.7%), but no significant difference in sexes was observed for these factors. Inheritance is also very prominent in diversity Factor 1, which is exactly corroborated with our previous findings. The present results are similar with the earlier results of finger ridge count diversity in twin data, which suggested that finger ridge count diversity is under genetic control.

  5. Twins and the paradox of dental-age estimations: a caution for researchers and clinicians.

    PubMed

    Pechníková, M; De Angelis, D; Gibelli, D; Vecchio, V; Cameriere, R; Zeqiri, B; Cattaneo, C

    2014-08-01

    The biological age difference among twins is frequently an issue in studies of genetic influence on various dental features, particularly dental development. The timing of dental development is a crucial issue also for many clinicians and researchers. The aim of this study was therefore to verify within groups of twins how dental development differs, by applying Demirjian's method, Mincer's charts of development of third molars and two of Cameriere's methods for dental age estimation, which are among the most popular methods both in the clinical and the forensic scenario. The sample consisted of 64 twin pairs: 21 monozygotic, 30 dizygotic same-sex and 13 dizygotic opposite-sex with an age range between 5.8 and 22.6 years. Dental age was determined from radiographs using the mentioned methods. Results showed that dental age of monozygotic twins is not identical even if they share all their genes. The mean intra-pair difference of monozygotic pairs was low and similar to the difference in dizygotic same-sex twins; the maximum difference between monozygotic twins, however, was surprisingly large (nearly two years). This should lead to some circumspection in the interpretation of systematic estimations of dental age both in the clinical and forensic scenario. PMID:24951409

  6. Twins and the paradox of dental-age estimations: a caution for researchers and clinicians.

    PubMed

    Pechníková, M; De Angelis, D; Gibelli, D; Vecchio, V; Cameriere, R; Zeqiri, B; Cattaneo, C

    2014-08-01

    The biological age difference among twins is frequently an issue in studies of genetic influence on various dental features, particularly dental development. The timing of dental development is a crucial issue also for many clinicians and researchers. The aim of this study was therefore to verify within groups of twins how dental development differs, by applying Demirjian's method, Mincer's charts of development of third molars and two of Cameriere's methods for dental age estimation, which are among the most popular methods both in the clinical and the forensic scenario. The sample consisted of 64 twin pairs: 21 monozygotic, 30 dizygotic same-sex and 13 dizygotic opposite-sex with an age range between 5.8 and 22.6 years. Dental age was determined from radiographs using the mentioned methods. Results showed that dental age of monozygotic twins is not identical even if they share all their genes. The mean intra-pair difference of monozygotic pairs was low and similar to the difference in dizygotic same-sex twins; the maximum difference between monozygotic twins, however, was surprisingly large (nearly two years). This should lead to some circumspection in the interpretation of systematic estimations of dental age both in the clinical and forensic scenario.

  7. [Prenatal diagnosis of five cases of monochorionic-diamniotic twins discordant for karyotype analysis].

    PubMed

    Wu, Jianzhu; Zhou, Yi; Lin, Shaobin; Chen, Baojiang; Xie, Yingjun

    2015-10-01

    OBJECTIVE To explore the mechanism and diagnostic method for monochorionic-diamniotic twins discordant for karyotype analysis. METHODS Dual amniocentesis was performed on five pairs of monochorionic-diamniotic twins, which all consisted of a normal twin and one with multiple malformations revealed by ultrasound. Karyotype analysis was performed on amniocytes derived from each of the twins. Zygosity was also determined with DNA extracted from amniocytes with 16 polymorphic microsatellite markers. RESULTS Three cases of 45,X, one case of 47,XX,+9 and one case of 47,XY,+18 were detected among the abnormal twins, while the normal fetuses all had a normal karyotype. DNA analysis suggested that, in all cases, the twins have shared the 16 polymorphic microsatellite markers, which confirmed their monozygosity. CONCLUSION Monochorionic-diamniotic twins may be discordant for karyotyping, for which anaphase lagging, chromosomal non-disjunction and trisomy rescue may be the underlying reasons. As a simple method, dual amniocentesis can be used to obtain amniotic fluid samples for karyotype analysis and determination of zygosity for such twins. PMID:26418994

  8. The vector-like twin Higgs

    DOE PAGES

    Craig, Nathaniel; Knapen, Simon; Longhi, Pietro; Strassler, Matthew

    2016-07-01

    Here, we present a version of the twin Higgs mechanism with vector-like top partners. In this setup all gauge anomalies automatically cancel, even without twin leptons. The matter content of the most minimal twin sector is therefore just two twin tops and one twin bottom. The LHC phenomenology, illustrated with two example models, is dominated by twin glueball decays, possibly in association with Higgs bosons. We further construct an explicit four-dimensional UV completion and discuss a variety of UV completions relevant for both vector-like and fraternal twin Higgs models.

  9. The vector-like twin Higgs

    NASA Astrophysics Data System (ADS)

    Craig, Nathaniel; Knapen, Simon; Longhi, Pietro; Strassler, Matthew

    2016-07-01

    We present a version of the twin Higgs mechanism with vector-like top partners. In this setup all gauge anomalies automatically cancel, even without twin leptons. The matter content of the most minimal twin sector is therefore just two twin tops and one twin bottom. The LHC phenomenology, illustrated with two example models, is dominated by twin glueball decays, possibly in association with Higgs bosons. We further construct an explicit four-dimensional UV completion and discuss a variety of UV completions relevant for both vector-like and fraternal twin Higgs models.

  10. Failure of vincristine induce twinning

    NASA Technical Reports Server (NTRS)

    Binder, M.

    1984-01-01

    Mammalian ova do not contain axes of symmetry from which are derived embryonic axes of symmetry. Mammalian axis determination is an early embryologic event occurring at about the time that monozygous twinning in mice. (Kaufma MH & O'Shea KS, 1978, Nature 276:707) and an attempt was made to reproduce their work in several strains of mice. Over 3200 embryos were examined without any twins being found. To rule out the possibility that vincristine caused twinning plus some lethal malformation (with subsequent resorption of the embryo) the embryos were examined 36-60 hours after vincristine treatment.

  11. Fivefold twinned boron carbide nanowires.

    PubMed

    Fu, Xin; Jiang, Jun; Liu, Chao; Yuan, Jun

    2009-09-01

    Chemical composition and crystal structure of fivefold twinned boron carbide nanowires have been determined by electron energy-loss spectroscopy and electron diffraction. The fivefold cyclic twinning relationship is confirmed by systematic axial rotation electron diffraction. Detailed chemical analysis reveals a carbon-rich boron carbide phase. Such boron carbide nanowires are potentially interesting because of their intrinsic hardness and high temperature thermoelectric property. Together with other boron-rich compounds, they may form a set of multiply twinned nanowire systems where the misfit strain could be continuously tuned to influence their mechanical properties.

  12. Laser therapy for twin-to-twin transfusion syndrome (TTTS).

    PubMed

    Chalouhi, G E; Essaoui, M; Stirnemann, J; Quibel, T; Deloison, B; Salomon, L; Ville, Y

    2011-07-01

    Monochorionic twins are subjected to specific complications which originate in either imbalance or abnormality of the single placenta serving two twins including twin-to-twin transfusion syndrome. The diagnosis is well established in overt clinical forms with the association of polyuric polyhydramnios and oliguric oligohydramnios. The best treatment of cases presenting before 26 weeks of gestion is fetoscopic laser ablation of the intertwin anastomoses on the chorionic plate. Although subjected to subtle variations, the core technique follows robust guidelines which could help understanding and acquiring the required skills and experience to perform this procedure. However appropriate and tailored hands-on training and appropriate perinatal set-up are critical not only for surgical management but also for the follow-up and management of related complications.

  13. Special forms in twin pregnancy - asymmetric conjoined twins.

    PubMed

    Anca, F A; Negru, A; Mihart, A E; Grigoriu, C; Bohîlțea, R E

    2015-01-01

    Twin pregnancies generally represent a high-risk pregnancy. However, monozygous twins are real challenges for obstetricians due to the complications that may occur. Among the particular cases of monozygous twins in the University Emergency Hospital of Bucharest, Department of Obstetrics and Gynecology, a monochorial monoamniotic pregnancy with conjoined twins has been described. These particular medical circumstances require a deeper understanding of the vascular anatomical particularities. An accurate diagnosis implies a most detailed description of the morphological dynamics of the fetuses with the study of the impact of the vascular anomaly on their development so that the maximum chances of survival and the best outcome for the viable fetus can be obtained. The diagnosis of the most frequently associated anomalies is also extremely important. PMID:26361519

  14. HEREDITARY FACTORS IN NORMAL PERSONALITY TRAITS (AS MEASURED BY INVENTORIES). LOUISVILLE TWIN STUDY, RESEARCH REPORT NUMBER 19.

    ERIC Educational Resources Information Center

    VANDENBERG, STEVEN G.

    RESEARCH ON HEREDITARY FACTORS IN NORMAL PERSONALITY TRAITS, AS MEASURED BY INVENTORIES, HAS BEEN LIMITED BY THE FOLLOWING FACTORS--(1) DATA DRAWN FROM ADOLESCENT, NOT ADULT, TWINS, (2) OMISSION OF MENTALLY ILL TWINS, (3) SMALL SIZE OF SAMPLES, (4) VARIABILITY STUDIED ONLY WITHIN FAMILY, (5) SMALL, ISOLATED, UNCOORDINATED STUDIES, AND (6) PROBLEMS…

  15. PTX3 genetic variation and dizygotic twinning in The Gambia: could pleiotropy with innate immunity explain common dizygotic twinning in Africa?

    PubMed Central

    Sirugo, Giorgio; Velez Edwards, Digna R.; Ryckman, Kelli K.; Bisseye, Cyrille; White, Marquitta J.; Kebbeh, Bunja; Morris, Gerard A. J.; Adegbola, Richard A.; Tacconelli, Alessandra; Predazzi, Irene; Novelli, Giuseppe; Vannberg, Fredrik O.; Odunsi, Kunle; Page, Grier P.; Williams, Scott M.

    2013-01-01

    Dizygotic (DZ) twinning has a genetic component and is common among sub-Saharan Africans; in The Gambia its frequency is up to 3% of live births. Variation in Pentraxin 3 (PTX3), a soluble pattern recognition receptor that plays an important role both in humoral innate immunity and in female fertility, has been associated with resistance to M. tuberculosis infection and to P. aeruginosa infection in cystic fibrosis patients. We tested whether PTX3 variants in Gambian women associate with DZ twinning, by genotyping five PTX3 single nucleotide polymorphisms (SNPs) in 130 sister pairs (96 full sibs and 34 half sibs) who had DZ twins. We found that two, three and five SNP haplotypes differed in frequency between twinning mothers and those without a history of twinning (from p = 0.006 to 3.03e-06 for two SNP and three SNP haplotypes, respectively). Twinning mothers and West African tuberculosis-controls from a previous study shared several frequent haplotypes. Most importantly, our data are consistent with the previously reported association of PTX3 and female fertility in a West African sample from Ghana. Taken together, these results indicate that selective pressure on PTX3 variants that affect the innate immune response to infectious agents, could also produce the observed high incidence of DZ twinning in Gambians. PMID:22834944

  16. Genetic Regulation of Acquired Immune Responses to Antigens of Mycobacterium tuberculosis: a Study of Twins in West Africa

    PubMed Central

    Jepson, Annette; Fowler, Amanda; Banya, Winston; Singh, Mahavir; Bennett, Steve; Whittle, Hilton; Hill, Adrian V. S.

    2001-01-01

    The role of genetic factors in clinical tuberculosis is increasingly recognized; how such factors regulate the immune response to Mycobacterium tuberculosis in healthy individuals is unclear. In this study of 255 adult twin pairs residing in The Gambia, West Africa, it is apparent that memory T-cell responses to secreted mycobacterial antigens (85-kDa antigen complex, “short-term culture filtrate,” and peptides from the ESAT-6 protein), as well as to the 65-kDa heat shock protein, are subject to effective genetic regulation. The delayed hypersensitivity response to intradermal tuberculin also demonstrates significant genetic variance, while quantitative T-cell and antibody responses to the 38-kDa cell membrane protein appear to be determined largely by environmental factors. Such findings have implications for vaccine development. PMID:11349068

  17. Fetal cardiovascular hemodynamics in twin-twin transfusion syndrome.

    PubMed

    Wohlmuth, Christoph; Gardiner, Helena M; Diehl, Werner; Hecher, Kurt

    2016-06-01

    Twin-twin transfusion syndrome (TTTS) complicates 10-15% of monochorionic-diamniotic (MCDA) pregnancies. It originates from unbalanced transfer of fluid and vasoactive mediators from one twin to its co-twin via placental anastomoses. This results in hypovolemia in the donor and hypervolemia and vasoconstriction in the recipient twin. Consequently, the recipient demonstrates cardiovascular alterations including atrioventricular valve regurgitation, diastolic dysfunction, and pulmonary stenosis/atresia that do not necessarily correlate with Quintero-stages. Selective fetoscopic laser photocoagulation of placental vascular anastomoses disrupts the underlying pathophysiology and usually improves cardiovascular function in the recipient with normalization of systolic and diastolic function within weeks after treatment. Postnatal studies have demonstrated early decreased arterial distensibility in ex-donor twins, but 10-year follow up is encouraging with survivors showing normal cardiovascular function after TTTS. However, prediction and appropriate early management of TTTS remain poor. Assessment of the cardiovascular system provides additional insight into the pathophysiology and severity of TTTS and may permit more targeted early surveillance of MCDA pregnancies in future. It should form an integral part of the diagnostic algorithm. PMID:26872246

  18. Monozygotic twins affected with major depressive disorder have greater variance in methylation than their unaffected co-twin.

    PubMed

    Byrne, E M; Carrillo-Roa, T; Henders, A K; Bowdler, L; McRae, A F; Heath, A C; Martin, N G; Montgomery, G W; Krause, L; Wray, N R

    2013-01-01

    Our understanding of major depressive disorder (MDD) has focused on the influence of genetic variation and environmental risk factors. Growing evidence suggests the additional role of epigenetic mechanisms influencing susceptibility for complex traits. DNA sequence within discordant monozygotic twin (MZT) pairs is virtually identical; thus, they represent a powerful design for studying the contribution of epigenetic factors to disease liability. The aim of this study was to investigate whether specific methylation profiles in white blood cells could contribute to the aetiology of MDD. Participants were drawn from the Queensland Twin Registry and comprised 12 MZT pairs discordant for MDD and 12 MZT pairs concordant for no MDD and low neuroticism. Bisulphite treatment and genome-wide interrogation of differentially methylated CpG sites using the Illumina Human Methylation 450 BeadChip were performed in WBC-derived DNA. No overall difference in mean global methylation between cases and their unaffected co-twins was found; however, the differences in females was significant (P=0.005). The difference in variance across all probes between affected and unaffected twins was highly significant (P<2.2 × 10⁻¹⁶), with 52.4% of probes having higher variance in cases (binomial P-value<2.2 × 10⁻¹⁶). No significant differences in methylation were observed between discordant MZT pairs and their matched concordant MZT (permutation minimum P=0.11) at any individual probe. Larger samples are likely to be needed to identify true associations between methylation differences at specific CpG sites. PMID:23756378

  19. Effects of Smoking on Coronary Microcirculatory Function: A Twin Study

    PubMed Central

    Rooks, Cherie; Faber, Tracy; Votaw, John; Veledar, Emir; Goldberg, Jack; Raggi, Paolo; Quyyumi, Arshed A.; Bremner, J. Douglas; Vaccarino, Viola

    2011-01-01

    Background In asymptomatic smokers, coronary microcirculatory dysfunction, assessed by coronary flow reserve (CFR), is an early indicator of cardiovascular risk. Inflammation and oxidative stress may be the mechanisms through which smoking affects the microvasculature. Objectives The purpose of this study was to determine the relationship between smoking and CFR, taking into account potential shared genetic effects. Methods We examined 360 male middle aged twins (288 non-smokers and 72 smokers), including 46 twin pairs discordant for current smoking. Coronary flow reserve (CFR) in response to adenosine was measured with positron emission tomography [N13] ammonia and quantitation of coronary blood flow at rest and after adenosine stress. Inflammation was assessed by measuring interleukin-6 and C-reactive protein, and oxidative stress was determined by measuring plasma hydroperoxides, glutathione (GSH), the oxidized form of GSH, GSSG, and the ratio of GSH to GSSG. Results CFR was significantly lower in smokers compared to nonsmokers (2.25 vs. 2.75, p<0.01). This relationship persisted after accounting for known cardiovascular disease risk factors, and was marginally affected by adjusting for inflammatory and oxidative stress biomarkers. In addition, in smoking-discordant twin pairs, CFR in the smoking twin was significantly lower than in the non-smoking co-twin (2.25 vs. 2.67, p = 0.03) even after adjustment for cardiovascular risk factors. Conclusions Our results demonstrate the adverse effects of smoking in the early phases of cardiovascular disease. Mechanisms other than peripherally-measured inflammation and oxidative stress are involved. PMID:21315354

  20. Does a college education reduce depressive symptoms in American young adults?

    PubMed

    McFarland, Michael J; Wagner, Brandon G

    2015-12-01

    Higher levels of educational attainment are consistently associated with better mental health. Whether this association represents an effect of education on mental health, however, is less clear as omitted variable bias remains a pressing concern with education potentially serving as a proxy for unobserved factors including family background and genetics. To combat this threat and come closer to a causal estimate of the effect of education on depressive symptoms, this study uses data on 231 monozygotic twin pairs from The National Longitudinal Study of Adolescent to Adult Health and employs a twin-pair difference-in-difference design to account for both unobserved shared factors between twin pairs (e.g. home, school, and neighborhood environment throughout childhood) and a number of observed non-shared but theoretically relevant factors (e.g. cognitive ability, personality characteristics, adolescent health). We find an inverse association between possessing a college degree and depressive symptoms in both conventional and difference-in-difference models. Results of this study also highlight the potentially overlooked role of personality characteristics in the education and mental health literature.

  1. "Mother's child" and "father's child" among twins. A longitudinal twin study from pregnancy to 21 years age, with special reference to development and psychiatric disorders.

    PubMed

    Moilanen, I; Pennanen, P

    1997-01-01

    234 pairs of twins were studied from pregnancy up to 21 years of age on the basis of records from maternity hospitals, neonatal wards and children's health centres and questionnaires filled in by the parents when the twins were aged 2-10 and 12-21 years, and by the twins themselves at age 12-21. 74 twins were personally interviewed about human relationships in their families and with the Present State Examination (PSE) at age 15-21. When the evaluation of parental preference was made by the parents, the mother's favourites had learned to speak earlier and were more often the psychic leader of the pair, but they more often had sleeping difficulties and other psychosomatic symptoms in adolescence. They were most often scored in class 2-3, non-specific neurotic symptoms in the PSE, but none of them was placed in the higher classes of possible or probable psychiatric disorder. Mothers seem to develop a tighter affectionate bond towards their favourites than do fathers, thus inducing a good basic trust and faster language acquisition in childhood, but probably also transient non-specific neurotic symptoms in adolescence in face of the developmental task of entering autonomous adulthood. The father's favorites were more often the physical leaders of the pair, showed less accident proneness and most often reported tendencies towards autonomy from their co-twins, thus indicating that the fathers' attitudes may be more encouraging towards independence. As the least psychosomatic symptoms were seen in twins in the intermediate position regarding parental preference, it seems reasonable that the division of twins between parents on the grounds of favouritism should not be strict. PMID:9862010

  2. Differences in Religiousness in Opposite-Sex and Same-Sex Twins in a Secular Society

    PubMed Central

    Ahrenfeldt, Linda J.; Lindahl-Jacobsen, Rune; Möller, Sören; Christensen, Kaare; Hvidtjørn, Dorte; Hvidt, Niels Christian

    2016-01-01

    Sex differences in religion are well known, with females generally being more religious than males, and shared environmental factors have been suggested to have a large influence on religiousness. Twins from opposite-sex (OS) and same-sex (SS) pairs may differ because of a dissimilar psycho-social rearing environment and/or because of different exposures to hormones in utero. We hypothesized that OS females may display more masculine patterns of religiousness and, vice versa, that OS males may display more feminine patterns. We used a web-based survey conducted in Denmark, which is a secular society. The survey included 2,997 twins aged 20–40 years, identified through the population-based Danish Twin Registry. We applied la Cour and Hvidt’s adaptation of Fishman’s three conceptual dimensions of meaning: Cognition, Practice, and Importance, and we used Pargament’s measure of religious coping (RCOPE) for the assessment of positive and negative religious coping patterns. Differences between OS and SS twins were investigated using logistic regression for each sex. The analyses were adjusted for dependence within twin pairs. No significant differences in religiousness and religious coping were found for OS and SS twins except that more OS than SS females were members of the Danish National Evangelical Lutheran Church and fewer OS than SS females were Catholic, Muslim, or belonged to other religious denominations. Moreover, OS males at age 12 had higher rates of church attendance than did SS males. This study did not provide evidence for masculinization of female twins with male co-twins with regard to religiousness. Nor did it show any significant differences between OS and SS males except from higher rates of church attendance in childhood among males with female co-twins. PMID:26689907

  3. Differences in Religiousness in Opposite-Sex and Same-Sex Twins in a Secular Society.

    PubMed

    Ahrenfeldt, Linda J; Lindahl-Jacobsen, Rune; Möller, Sören; Christensen, Kaare; Hvidtjørn, Dorte; Hvidt, Niels Christian

    2016-02-01

    Sex differences in religion are well known, with females generally being more religious than males, and shared environmental factors have been suggested to have a large influence on religiousness. Twins from opposite-sex (OS) and same-sex (SS) pairs may differ because of a dissimilar psycho-social rearing environment and/or because of different exposures to hormones in utero. We hypothesized that OS females may display more masculine patterns of religiousness and, vice versa, that OS males may display more feminine patterns. We used a web-based survey conducted in Denmark, which is a secular society. The survey included 2,997 twins aged 20-40 years, identified through the population-based Danish Twin Registry. We applied la Cour and Hvidt's adaptation of Fishman's three conceptual dimensions of meaning: Cognition, Practice, and Importance, and we used Pargament's measure of religious coping (RCOPE) for the assessment of positive and negative religious coping patterns. Differences between OS and SS twins were investigated using logistic regression for each sex. The analyses were adjusted for dependence within twin pairs. No significant differences in religiousness and religious coping were found for OS and SS twins except that more OS than SS females were members of the Danish National Evangelical Lutheran Church and fewer OS than SS females were Catholic, Muslim, or belonged to other religious denominations. Moreover, OS males at age 12 had higher rates of church attendance than did SS males. This study did not provide evidence for masculinization of female twins with male co-twins with regard to religiousness. Nor did it show any significant differences between OS and SS males except from higher rates of church attendance in childhood among males with female co-twins. PMID:26689907

  4. Are differences between twins a result of mutual rivalry?

    PubMed

    Borg, J G

    1997-01-01

    The sexual index included in the Szondi test makes it possible to define the domains of an individual's "internal sex" or gender-especially the degree of the subject's bisexuality. This index was employed in a comparison between partners reared together in 62 monozygotic and 23 dizygotic pairs of twins. The observed incongruence in 1/3 MZ pairs would not appear to derive totally from errors of measurement. In most of these pairs it is competition which underlies the incongruence seen on the sexual index. It was further observed that the congruence here as in general in female pairs is clearly more marked than in males. A hypothesis was proposed, whereby competition for dominance is a distinctively major-tonality (masculinity) characteristic. The incongruence is more conspicuous among males because males are in general more markedly major-toned than females. This hypothesis was borne out. It is thus necessary here as in general to adopt two sex variables in parallel: external (i.e. matricular) sex and internal sex (gender). It is due to the presence of these competitive pairs that the means and especially deviations of twins' test results will consistently diverge from those in the population at large. PMID:9298156

  5. Neuronal intranuclear inclusion disease in identical twins.

    PubMed

    Haltia, M; Somer, H; Palo, J; Johnson, W G

    1984-04-01

    A pair of female identical twins exhibited slurred speech, nystagmus, and oculogyral spasms starting at age 11. The patients then had episodic rage, extrapyramidal and lower motor neuron abnormalities, and grand mal seizures, but retained largely normal intelligence, until death at age 21. Severe loss of nigral and craniospinal motor neurons was noted postmortem. Round, eosinophilic, autofluorescent inclusion bodies, 3 to 10 microns in diameter, were observed in the nuclei of most nerve cell types of the central and peripheral nervous systems and retina. Ultrastructurally the inclusions appeared as masses of filaments without a limiting membrane, the constituent filaments having a diameter of 8.5 to 9.5 nm. Histochemical results suggested the presence of proteins with a high content of tryptophan. Four similar cases have been reported previously under various designations. We propose the name neuronal intranuclear inclusion disease for the disorder. PMID:6331275

  6. Aragonite twinning in gastropod nacre

    NASA Astrophysics Data System (ADS)

    Mukai, Hiroki; Saruwatari, Kazuko; Nagasawa, Hiromichi; Kogure, Toshihiro

    2010-10-01

    Aragonite twinning in gastropod nacre has been investigated using scanning electron microscopy (SEM), electron back-scattered diffraction (EBSD), and transmission electron microscopy (TEM) with the focused ion beam (FIB) sample preparation technique. At the growth front of nacre, Haliotis discus hannai and Omphalius rusticus form a "stack-of-coins" structures, which consist of pseudo-hexagonal and elliptical aragonite tablets, respectively. SEM, EBSD, and TEM analyses revealed that these tablets are monolithic single crystal and almost free of the {1 1 0} twins that are common in aragonite of biotic or abiotic origin. The longest diagonal of the hexagon and the longer axis of the ellipse are parallel to the a-axis of aragonite. The crystal orientation of each tablet in a stack, measured by TEM-Kikuchi pattern analysis, is almost the same but there is occasionally {1 1 0} twin-like relationship between adjacent tablets along the stacking. On the other hand, the fibrous aragonite layer formed prior to the nacreous structure is composed of polycrystalline aragonite with high density of {1 1 0} twins. TEM observation suggests that the interlamellar organic sheet prevents the inheritance of the twins, by selecting only single domain of the twins, through the mineral bridge.

  7. Cohort Profile: Swedish Twin Study on Prediction and Prevention of Asthma (STOPPA).

    PubMed

    Almqvist, Catarina; Örtqvist, Anne K; Ullemar, Vilhelmina; Lundholm, Cecilia; Lichtenstein, Paul; Magnusson, Patrik K E

    2015-06-01

    Asthma is a common childhood disease and several risk factors have been identified; however, the impact of genes and environment is not fully understood. The aim of the Swedish Twin study On Prediction and Prevention of Asthma (STOPPA) is to identify environmental (birth characteristics and early life) and genetic (including epigenetic) factors as determinants for asthmatic disease. Based on the Child and Adolescent Twin Study in Sweden (CATSS) (parental interview at 9 or 12 years, N ~23,900) and an asthma and/or wheezing algorithm, we identified a sample of monozygotic (MZ) and dizygotic (DZ) same-sexed twin pairs. The twin pairs were classified as asthma concordant (ACC), asthma discordant (ADC) and healthy concordant (HCC). A sample of 9- to 14-year-old twins and their parents were invited to participate in a clinical examination. Background characteristics were collected in questionnaires and obtained from the National Health Registers. A clinical examination was performed to test lung function and capacity (spirometry with reversibility test and exhaled nitric oxide) and collect blood (serology and DNA), urine (metabolites), feces (microbiota), and saliva (cortisol). In total, 376 twin pairs (752 individual twins) completed the study, response rate 52%. All participating twins answered the questionnaire and >90% participated in lung function testing, blood-, and saliva sampling. This article describes the design, recruitment, data collection, measures, and background characteristics, as well as ongoing and planned analyses in STOPPA. Potential gains of the study include the identification of biomarkers, the emergence of candidates for drug development, and new leads for prevention of asthma and allergic disease. PMID:25900604

  8. Fetal programming by co-twin rivalry in sheep.

    PubMed

    Casellas, J; Caja, G

    2014-01-01

    Fetal rivalry for space and nutrients compromises intrauterine environment and fetal growth, this leading to further consequences during adult life (i.e., fetal programming). Focusing on sheep, relevant fetal programming effects have been revealed on body composition and growth although little is known about their potential impact on the reproductive performance of adult ewes. This research focused on the analysis of fetal programming-related effects on 41,475 litter size (LS) records from 7,177 purebred Ripollesa ewes. Fetal programming sources of variation accounted for the linear and quadratic effect of absolute birth BW (ABBW), relative birth BW (RBBW) of twin-born ewes (i.e., both magnitude and direction of the birth BW difference between the ewe and its co-twin), and sex of twin ewe's littermate (SLM). More specifically, data were analyzed under a threshold mixed model and the statistical relevance of models accounting for different combinations of ABBW, RBBW, and SLM effects was compared by Bayes factors (BF; i.e., the ratio between the posterior probability of 2 competing models). The model accounting for RBBW and discarding both ABBW and SLM effects was clearly preferred; its posterior probability was 35.2 to 362.3 times higher than from remaining models and provided very strong (31.6 < BF < 100) and decisive evidences (BF > 100) supporting the relevance of RBBW and the negligibility of both ABBW and SLM. Single-born ewes were included as reference group and they reached a predicted LS of 1.189 lambs per lambing. Twin-born ewes being >600 g lighter than their co-twins suffered from an impaired reproductive ability with 1.162 lambs per lambing (95% credible interval [95CI], 1.147 to 1.179), and this estimate increased until ewes were 151 to 300 g lighter than their co-twins (1.226 lambs per lambing; 95CI, 1.208 to 1.244). Remaining categories (i.e., ewes being heavier or equal than their co-twins) did not provide significant differences and showed an

  9. DNA methylation profiling in breast cancer discordant identical twins identifies DOK7 as novel epigenetic biomarker

    PubMed Central

    Esteller, Manel

    2013-01-01

    Using whole blood from 15 twin pairs discordant for breast cancer and high-resolution (450K) DNA methylation analysis, we identified 403 differentially methylated CpG sites including known and novel potential breast cancer genes. Confirming the results in an independent validation cohort of 21 twin pairs determined the docking protein DOK7 as a candidate for blood-based cancer diagnosis. DNA hypermethylation of the promoter region was also seen in primary breast cancer tissues and cancer cell lines. Hypermethylation of DOK7 occurs years before tumor diagnosis, suggesting a role as a powerful epigenetic blood-based biomarker as well as providing insights into breast cancer pathogenesis. PMID:23054610

  10. DNA methylation profiling in breast cancer discordant identical twins identifies DOK7 as novel epigenetic biomarker.

    PubMed

    Heyn, Holger; Carmona, F Javier; Gomez, Antonio; Ferreira, Humberto J; Bell, Jordana T; Sayols, Sergi; Ward, Kirsten; Stefansson, Olafur A; Moran, Sebastian; Sandoval, Juan; Eyfjord, Jorunn E; Spector, Tim D; Esteller, Manel

    2013-01-01

    Using whole blood from 15 twin pairs discordant for breast cancer and high-resolution (450K) DNA methylation analysis, we identified 403 differentially methylated CpG sites including known and novel potential breast cancer genes. Confirming the results in an independent validation cohort of 21 twin pairs determined the docking protein DOK7 as a candidate for blood-based cancer diagnosis. DNA hypermethylation of the promoter region was also seen in primary breast cancer tissues and cancer cell lines. Hypermethylation of DOK7 occurs years before tumor diagnosis, suggesting a role as a powerful epigenetic blood-based biomarker as well as providing insights into breast cancer pathogenesis. PMID:23054610

  11. A Critical Assessment of the Equal-Environment Assumption of the Twin Method for Schizophrenia

    PubMed Central

    Fosse, Roar; Joseph, Jay; Richardson, Ken

    2015-01-01

    The classical twin method (CTM) is central to the view that schizophrenia is ~80% heritable. The CTM rests on the equal-environment assumption (EEA) that identical and fraternal twin pairs experience equivalent trait-relevant environmental exposures. The EEA has not been directly tested for schizophrenia with measures of child social adversity, which is particularly etiologically relevant to the disorder. However, if child social adversity is more similar in identical than fraternal pairs in the general twin population, the EEA is unlikely to be valid for schizophrenia, a question which we tested in this study. Using results from prior twin studies, we tested if intraclass correlations for the following five categories of child social adversity are larger in identical than fraternal twins: bullying, sexual abuse, physical maltreatment, emotional neglect and abuse, and general trauma. Eleven relevant studies that encompassed 9119 twin pairs provided 24 comparisons of intraclass correlations, which we grouped into the five social exposure categories. Fisher’s z-test revealed significantly higher correlations in identical than fraternal pairs for each exposure category (z ≥ 3.53, p < 0.001). The difference remained consistent across gender, study site (country), sample size, whether psychometric instruments were used, whether interviewing was proximate or distant to the exposures, and whether informants were twins or third persons. Combined with other evidence that the differential intraclass correlation for child social adversity cannot be explained by evocative gene–environment covariation, our results indicate that the CTM does not provide any valid indication of genomic effects in schizophrenia. PMID:25972816

  12. A critical assessment of the equal-environment assumption of the twin method for schizophrenia.

    PubMed

    Fosse, Roar; Joseph, Jay; Richardson, Ken

    2015-01-01

    The classical twin method (CTM) is central to the view that schizophrenia is ~80% heritable. The CTM rests on the equal-environment assumption (EEA) that identical and fraternal twin pairs experience equivalent trait-relevant environmental exposures. The EEA has not been directly tested for schizophrenia with measures of child social adversity, which is particularly etiologically relevant to the disorder. However, if child social adversity is more similar in identical than fraternal pairs in the general twin population, the EEA is unlikely to be valid for schizophrenia, a question which we tested in this study. Using results from prior twin studies, we tested if intraclass correlations for the following five categories of child social adversity are larger in identical than fraternal twins: bullying, sexual abuse, physical maltreatment, emotional neglect and abuse, and general trauma. Eleven relevant studies that encompassed 9119 twin pairs provided 24 comparisons of intraclass correlations, which we grouped into the five social exposure categories. Fisher's z-test revealed significantly higher correlations in identical than fraternal pairs for each exposure category (z ≥ 3.53, p < 0.001). The difference remained consistent across gender, study site (country), sample size, whether psychometric instruments were used, whether interviewing was proximate or distant to the exposures, and whether informants were twins or third persons. Combined with other evidence that the differential intraclass correlation for child social adversity cannot be explained by evocative gene-environment covariation, our results indicate that the CTM does not provide any valid indication of genomic effects in schizophrenia. PMID:25972816

  13. Heisenberg-limited interferometry with pair coherent states and parity measurements

    SciTech Connect

    Gerry, Christopher C.; Mimih, Jihane

    2010-07-15

    After reviewing parity-measurement-based interferometry with twin Fock states, which allows for supersensitivity (Heisenberg limited) and super-resolution, we consider interferometry with two different superpositions of twin Fock states, namely, two-mode squeezed vacuum states and pair coherent states. This study is motivated by the experimental challenge of producing twin Fock states on opposite sides of a beam splitter. We find that input two-mode squeezed states, while allowing for Heisenberg-limited sensitivity, do not yield super-resolutions, whereas both are possible with input pair coherent states.

  14. Sunset over Twin Peaks

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image was taken by the Imager for Mars Pathfinder (IMP) about one minute after sunset on Mars on Sol 21. The prominent hills dubbed 'Twin Peaks' form a dark silhouette at the horizon, while the setting sun casts a pink glow over the darkening sky. The image was taken as part of a twilight study which indicates how the brightness of the sky fades with time after sunset. Scientists found that the sky stays bright for up to two hours after sunset, indicating that Martian dust extends very high into the atmosphere.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  15. Twin Dimples Intrigue Scientists

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image from the Mars Exploration Rover Opportunity is part of the first set of pictures that was returned to Earth after the rover exited 'Eagle Crater.' Scientists are busy analyzing Opportunity's new view of the plains of Meridiani Planum. The plentiful ripples are a clear indication that wind is the primary geologic process currently in effect on the plains. On the left of the image are two depressions--each about a meter (about 3.3 feet) across--that feature bright spots in their centers. One possibility is that the bright material is similar in composition to the rocks in Eagle Crater's outcrop and the surrounding darker material is what's referred to as 'lag deposit,' or erosional remnants that are much harder and more difficult to wear away. These twin dimples might be revealing pieces of a larger outcrop that lies beneath. The depression closest to Opportunity is whimsically referred to as 'Homeplate' and the one behind it as 'First Base.' The rover's panoramic camera is set to take detailed images of the depressions today, on Opportunity's 58th sol. The backshell and parachute that helped protect the rover and deliver it safely to the surface of Mars are also visible near the horizon, in the center of the image. This image was taken by the rover's navigation camera.

  16. Twin kernel embedding.

    PubMed

    Guo, Yi; Gao, Junbin; Kwan, Paul W

    2008-08-01

    In most existing dimensionality reduction algorithms, the main objective is to preserve relational structure among objects of the input space in a low dimensional embedding space. This is achieved by minimizing the inconsistency between two similarity/dissimilarity measures, one for the input data and the other for the embedded data, via a separate matching objective function. Based on this idea, a new dimensionality reduction method called Twin Kernel Embedding (TKE) is proposed. TKE addresses the problem of visualizing non-vectorial data that is difficult for conventional methods in practice due to the lack of efficient vectorial representation. TKE solves this problem by minimizing the inconsistency between the similarity measures captured respectively by their kernel Gram matrices in the two spaces. In the implementation, by optimizing a nonlinear objective function using the gradient descent algorithm, a local minimum can be reached. The results obtained include both the optimal similarity preserving embedding and the appropriate values for the hyperparameters of the kernel. Experimental evaluation on real non-vectorial datasets confirmed the effectiveness of TKE. TKE can be applied to other types of data beyond those mentioned in this paper whenever suitable measures of similarity/dissimilarity can be defined on the input data. PMID:18566501

  17. Two male adults with pathogenic AUTS2 variants, including a two-base pair deletion, further delineate the AUTS2 syndrome

    PubMed Central

    Beunders, Gea; de Munnik, Sonja A; Van der Aa, Nathalie; Ceulemans, Berten; Voorhoeve, Els; Groffen, Alexander J; Nillesen, Willy M; Meijers-Heijboer, Elizabeth J; Frank Kooy, R; Yntema, Helger G; Sistermans, Erik A

    2015-01-01

    AUTS2 syndrome is characterized by low birth weight, feeding difficulties, intellectual disability, microcephaly and mild dysmorphic features. All affected individuals thus far were caused by chromosomal rearrangements, variants at the base pair level disrupting AUTS2 have not yet been described. Here we present the full clinical description of two affected men with intragenic AUTS2 variants (one two-base pair deletion in exon 7 and one deletion of exon 6). Both variants are de novo and are predicted to cause a frameshift of the full-length transcript but are unlikely to affect the shorter 3′ transcript starting in exon 9. The similarities between the phenotypes of both men are striking and further support that AUTS2 syndrome is a single gene disorder. PMID:25205402

  18. Langerhans cell histiocytosis in monozygotic twins with central diabetes insipidus and hypophyseal masses

    PubMed Central

    Wei, Sung-Tai; Chen, Der-Cherng; Cho, Der-Yang; Lin, Hung-Lin

    2015-01-01

    Langerhans cell histiocytosis (LCH) is a systemic disease mainly affecting children and young adults. It can manifest as single system disorder or multi-system involvement. When the central nervous system is involved, the hypothalamic–pituitary axis is the most common location affected. Herein we report a rare case of Langerhans cell histiocytosis in monozygotic twins both with central diabetes and hypophyseal masses. This is the first report about LCH in monozygotic twins with hypophyseal lesions. PMID:25972939

  19. Synesthesia in twins: incomplete concordance in monozygotes suggests extragenic factors.

    PubMed

    Bosley, Hannah G; Eagleman, David M

    2015-06-01

    Colored-sequence synesthesia (CSS) is a neurological condition in which sequential stimuli such as letters, numbers, or days of the week trigger simultaneous, involuntary color perception. Although the condition appears to run in families and several studies have sought a genetic link, the genetic contribution to synesthesia remains unclear. We conducted the first comparative twin study of CSS and found that CSS has a pairwise concordance of 73.9% in monozygotic twins, and a pairwise concordance of 36.4% in dizygotic twins. In line with previous studies, our results suggest a heritable element of synesthesia. However, consonant with the findings of previous single-pair case studies, our large sample size verifies that synesthesia is not completely conferred by genetics; if it were, monozygotic twins should have 100% concordance. These findings implicate a genetic mechanism of CSS that may work differently than previously thought: collectively, our data suggest that synesthesia is a heritable condition with incomplete penetrance that is substantially influenced by epigenetic and environmental factors.

  20. Synesthesia in twins: incomplete concordance in monozygotes suggests extragenic factors.

    PubMed

    Bosley, Hannah G; Eagleman, David M

    2015-06-01

    Colored-sequence synesthesia (CSS) is a neurological condition in which sequential stimuli such as letters, numbers, or days of the week trigger simultaneous, involuntary color perception. Although the condition appears to run in families and several studies have sought a genetic link, the genetic contribution to synesthesia remains unclear. We conducted the first comparative twin study of CSS and found that CSS has a pairwise concordance of 73.9% in monozygotic twins, and a pairwise concordance of 36.4% in dizygotic twins. In line with previous studies, our results suggest a heritable element of synesthesia. However, consonant with the findings of previous single-pair case studies, our large sample size verifies that synesthesia is not completely conferred by genetics; if it were, monozygotic twins should have 100% concordance. These findings implicate a genetic mechanism of CSS that may work differently than previously thought: collectively, our data suggest that synesthesia is a heritable condition with incomplete penetrance that is substantially influenced by epigenetic and environmental factors. PMID:25704836

  1. The Russian School Twin Registry (RSTR): project PROGRESS.

    PubMed

    Kovas, Yulia; Galajinsky, Eduard V; Boivin, Michel; Harold, Gordon T; Jones, Alice; Lemelin, Jean-Pascal; Luo, Yu; Petrill, Stephen A; Plomin, Robert; Tikhomirova, Tatiana; Zhou, Xinlin; Malykh, Sergey

    2013-02-01

    The Russian School Twin Registry (RSTR) was established in 2012, supported by a grant from the Government of the Russian Federation. The main aim of the registry is to contribute to Progress in Education through Gene-Environment Studies (PROGRESS). The formation of the registry is ongoing and it is expected that most schools in the Russian Federation (approximately 50,000 schools) will contribute data to the registry. With a total of 13.7 million students in Grades 1-11 (ages 7-18), the potential number of twin pairs exceeds 100,000. Apart from the large sample size and its representative nature, the RSTR has one unique feature: in collaboration with the International Advisory Committee to the Registry, genetically sensitive cross-cultural investigations are planned, aided by the use of the common assessment instruments. Other strengths of the registry include the assessment of a large sample of non-twin school children, including those studying in the same classes as the twins in the registry. It is hoped that the RSTR will provide an important research platform for national and international educationally relevant research.

  2. Behavioral and environmental modification of the genetic influence on body mass index: A twin study

    PubMed Central

    Horn, Erin E.; Turkheimer, Eric; Strachan, Eric; Duncan, Glen E.

    2015-01-01

    Body mass index (BMI) has a strong genetic basis, with a heritability around 0.75, but is also influenced by numerous behavioral and environmental factors. Aspects of the built environment (e.g., environmental walkability) are hypothesized to influence obesity by directly affecting BMI, by facilitating or inhibiting behaviors such as physical activity that are related to BMI, or by suppressing genetic tendencies toward higher BMI. The present study investigated relative influences of physical activity and walkability on variance in BMI using 5,079 same-sex adult twin pairs (70% monozygotic, 65% female). High activity and walkability levels independently suppressed genetic variance in BMI. Estimating their effects simultaneously, however, suggested that the walkability effect was mediated by activity. The suppressive effect of activity on variance in BMI was present even with a tendency for low-BMI individuals to select into environments that require higher activity levels. Overall, our results point to community- or macro-level interventions that facilitate individual-level behaviors as a plausible approach to addressing the obesity epidemic among U.S. adults. PMID:25894925

  3. A Twin Study of ADHD Symptoms in Early Adolescence: Hyperactivity-Impulsivity and Inattentiveness Show Substantial Genetic Overlap but Also Genetic Specificity

    ERIC Educational Resources Information Center

    Greven, Corina U.; Rijsdijk, Fruhling V.; Plomin, Robert

    2011-01-01

    A previous paper in this journal revealed substantial genetic overlap between the ADHD dimensions of hyperactivity-impulsivity and inattentiveness in a sample of 8-year old twins drawn from a UK-representative population sample. Four years later, when the twins were 12 years old, more than 5,500 pairs drawn from the same sample were rated again on…

  4. Molecular dynamics simulation of albite twinning and pericline twinning in low albite

    NASA Astrophysics Data System (ADS)

    Li, Bin; Knowles, Kevin M.

    2013-07-01

    Two twinning laws, the albite law and the pericline law, are the predominant growth twinning modes in triclinic plagioclase feldspars such as low albite, NaAlSi3O8, in which the aluminum and silicon atoms are in an ordered arrangement on the tetrahedral sites of the aluminosilicate framework. In the terminology used formally to describe deformation twinning in a triclinic lattice, these twin laws can be described as Type I and Type II twin laws, respectively, with the pericline twin law being conjugate to the albite twin law. In this study, twin boundaries have been constructed for low albite according to these two twinning laws and studied by molecular dynamics simulation. The results show that suitably constructed twin boundary models are quite stable for both albite twinning and pericline twinning during molecular dynamics simulation. The calculated twin boundary energy of an albite twin is significantly lower than that of a pericline twin, in accord with the experimental observation that albite twinning is the more commonly observed mode seen in plagioclase feldspars. The results of the molecular dynamics simulations also agree with conclusions from the prior work of Starkey that glide twinning in low albite is not favoured energetically.

  5. [Twin pregnancy complicated by intrauterine death of one twin].

    PubMed

    Wilczyński, J; Jaczewski, B; Nowakowska, D; Wysocki, K; Szaflik, K; Oszukowski, P; Krasomski, G; Czichos, E

    2000-11-01

    In twin pregnancies single intrauterine death of one fetus is associated with significant morbidity and mortality of the surviving infant. The aims of our retrospective study were to review conditions of twin pregnancies complicated with SIUD in Polish Mother's Memorial Hospital in Łódź between 1989-1999 and to assess the fetal outcome when conservative management had undergone. In this study we reviewed 30 twin gestations involving the intrauterine death of one fetus. The incidence of preterm delivery among pregnancies with fetal death was 83.3%; Caesarean section was the method of delivery in 53.3% cases. Monochorionic placentation was found in 60%. Conservative management until there is no risk for the fetus is apt. PMID:11216164

  6. A Discordant Monozygotic Twin Design Shows Blunted Cortisol Reactivity Among Bullied Children

    PubMed Central

    Ouellet-Morin, Isabelle; Danese, Andrea; Bowes, Lucy; Shakoor, Sania; Ambler, Antony; Pariante, Carmine M.; Papadopoulos, Andrew S.; Caspi, Avshalom; Moffitt, Terrie E.; Arseneault, Louise

    2013-01-01

    Objective Childhood adverse experiences are known to engender persistent changes in stress-related systems and brain structures involved in mood, cognition, and behavior in animal models. Uncertainty remains about the causal effect of early stressful experiences on physiological response to stress in human beings, as the impact of these experiences has rarely been investigated while controlling for both genetic and shared environmental influences. Method We tested whether bullying victimization, a repeated adverse experience in childhood, influences cortisol responses to a psychosocial stress test (PST) using a discordant monozygotic (MZ) twin design. Thirty pairs (43.3% males) of 12-year-old MZ twins discordant for bullying victimization were identified in the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative 1994–1995 cohort of families with twins. Results Bullied and nonbullied MZ twins showed distinct patterns of cortisol secretion after the PST. Specifically, bullied twins exhibited a blunted cortisol response compared with their nonbullied MZ co-twins, who showed the expected increase. This difference in cortisol response to stress could not be attributed to children's genetic makeup, their familial environments, pre-existing and concomitant individual factors, or the perception of stress and emotional response to the PST. Conclusion Results from this natural experiment provide support for a causal effect of adverse childhood experiences on the neuroendocrine response to stress. PMID:21621141

  7. Monozygotic twins discordant for constitutive BRCA1 promoter methylation, childhood cancer and secondary cancer.

    PubMed

    Galetzka, Danuta; Hansmann, Tamara; El Hajj, Nady; Weis, Eva; Irmscher, Benjamin; Ludwig, Marco; Schneider-Rätzke, Brigitte; Kohlschmidt, Nicolai; Beyer, Vera; Bartsch, Oliver; Zechner, Ulrich; Spix, Claudia; Haaf, Thomas

    2012-01-01

    We describe monozygotic twins discordant for childhood leukemia and secondary thyroid carcinoma. We used bisulfite pyrosequencing to compare the constitutive promoter methylation of BRCA1 and several other tumor suppressor genes in primary fibroblasts. The affected twin displayed an increased BRCA1 methylation (12%), compared with her sister (3%). Subsequent bisulfite plasmid sequencing demonstrated that 13% (6 of 47) BRCA1 alleles were fully methylated in the affected twin, whereas her sister displayed only single CpG errors without functional implications. This between-twin methylation difference was also found in irradiated fibroblasts and untreated saliva cells. The BRCA1 epimutation may have originated by an early somatic event in the affected twin: approximately 25% of her body cells derived from different embryonic cell lineages carry one epigenetically inactivated BRCA1 allele. This epimutation was associated with reduced basal protein levels and a higher induction of BRCA1 after DNA damage. In addition, we performed a genome-wide microarray analysis of both sisters and found several copy number variations, i.e., heterozygous deletion and reduced expression of the RSPO3 gene in the affected twin. This monozygotic twin pair represents an impressive example of epigenetic somatic mosaicism, suggesting a role for constitutive epimutations, maybe along with de novo genetic alterations in recurrent tumor development.

  8. The effect of classroom environment on problem behaviors: a twin study.

    PubMed

    DiLalla, Lisabeth Fisher; Mullineaux, Paula Y

    2008-04-01

    Children's behavior problems, both internalizing and externalizing, are a function of both genetic and environmental influences. One potentially important environmental influence is the classroom environment. This study of 1941 monozygotic twin pairs examined whether children whose parents rated them as similarly high or low on a number of problem behaviors were rated in the same way by teachers when they were together versus separated in their classrooms at school. Results showed that twins in the same classrooms were rated by their teachers more similarly on each dimension of problem behavior than were twins who were separated into different classrooms, suggesting that the classroom environment is important in predicting differences between twins in terms of problem behaviors at school. In addition, parents' ratings of problem behaviors were lower for twins placed in the same classroom versus twins in different classrooms. Thus, there is reason to consider whether, at least during the early school years, parents should be allowed to make the decision to not separate twins at school.

  9. Vasospastic Angina in Identical Twins

    PubMed Central

    Yoshioka, Takayuki; Otsui, Kazunori; Suzuki, Atsushi; Ozawa, Toru; Iwata, Sachiyo; Takei, Asumi; Inoue, Nobutaka

    2015-01-01

    Patient: Male, 58 Final Diagnosis: Vasospastic angina Symptoms: Chest pain Medication: — Clinical Procedure: Medical treatment Specialty: Cardiology Objective: Rare disease Background: The clinical conditions of various diseases, including coronary artery disease, are determined by genetics and the environment. Previous investigations noted the significance of genetic mutations and polymorphisms in cases of coronary spasm. Case Report: We report on monozygotic identical twins who almost simultaneously presented with vasospastic angina. The 58-year-old younger twin was admitted to our hospital because of persistent chest pain. An electrocardiogram showed an inverted T wave in the left precordial leads. Coronary angiographies revealed a short left main trunk (LMT) and 50% stenosis at the proximal portion of the left anterior descending artery (LAD). Infusion of acetylcholine to his left coronary artery caused marked vasoconstriction associated with a sensation of chest oppression. Nitroglycerine completely reversed this response. Based on these findings, we diagnosed Twin A with vasospastic angina. At nearly the same time, his identical twin brother was diagnosed with vasospastic angina at another hospital. Comparison of both coronary angiograms indicated similar structure of coronary vessels, including short LMT and mild stenosis at the proximal portion of LAD. Conclusions: These 2 cases highlight the importance of genetic factors in the pathogenesis of vasospastic angina. It may be important for individuals to receive medical attention if their identical twin presents with vasospastic angina. PMID:26347942

  10. Paternal age and telomere length in twins: the germ stem cell selection paradigm.

    PubMed

    Hjelmborg, Jacob B; Dalgård, Christine; Mangino, Massimo; Spector, Tim D; Halekoh, Ulrich; Möller, Sören; Kimura, Masayuki; Horvath, Kent; Kark, Jeremy D; Christensen, Kaare; Kyvik, Kirsten O; Aviv, Abraham

    2015-08-01

    Telomere length, a highly heritable trait, is longer in offspring of older fathers. This perplexing feature has been attributed to the longer telomeres in sperm of older men and it might be an 'epigenetic' mechanism through which paternal age plays a role in telomere length regulation in humans. Based on two independent (discovery and replication) twin studies, comprising 889 twin pairs, we show an increase in the resemblance of leukocyte telomere length between dizygotic twins of older fathers, which is not seen in monozygotic twins. This phenomenon might result from a paternal age-dependent germ stem cell selection process, whereby the selected stem cells have longer telomeres, are more homogenous with respect to telomere length, and share resistance to aging.

  11. Bidirectional influences between maternal parenting and children's peer problems: a longitudinal monozygotic twin difference study.

    PubMed

    Yamagata, Shinji; Takahashi, Yusuke; Ozaki, Koken; Fujisawa, Keiko K; Nonaka, Koichi; Ando, Juko

    2013-03-01

    This twin study examined the bidirectional relationship between maternal parenting behaviors and children's peer problems that were not confounded by genetic and family environmental factors. Mothers of 259 monozygotic twin pairs reported parenting behaviors and peer problems when twins were 42 and 48 months. Path analyses on monozygotic twin difference scores revealed that authoritative parenting (the presence of consistent discipline and lack of harsh parenting) and peer problems simultaneously influenced each other. Authoritative parenting reduced peer problems, and peer problems increased authoritative parenting. Neither consistent discipline nor harsh parenting alone was associated with peer problems. These results suggest that maternal authoritative parenting works protectively in regard to children's peer problems, and peer problems can evoke such effective parenting.

  12. Phenotypic variability in monozygotic twins with neurofibromatosis 2

    SciTech Connect

    Baser, M.E.; Ragge, N.K.; Riccardi, V.M.

    1996-09-06

    Mutations in the neurofibromatosis 2 (NF2) tumor suppressor gene on chromosome 22q12 cause a clinically variable autosomal dominant syndrome characterized by bilateral vestibular schwannomas (VSs), other nervous system tumors, and early onset lenticular cataracts. We studied three pairs of monozygotic (MZ) twins with NF2, all with bilateral VSs, to separate genetic from nongenetic causes of clinical variability. The evaluation included gadolinium-enhanced high-resolution magnetic resonance imaging of the head and spine, neuro-ophthalmic examination with slit lamp, physical examination, and zygosity testing with microsatellite markers. Each MZ pair was concordant for general phenotypic subtype (mild or severe) and often for the affected organ systems. However, the MZ pairs were discordant for some features of disease presentation or progression. For example, all three pairs were discordant for presence or type of associated cranial tumors. We hypothesize that phenotypic differences between NF2 MZ twins are at least partly due to stochastic processes, such as the loss of the second NF2 allele or alleles of other genes. 42 refs., 1 tab.

  13. Nike Twins Seven Seven: Nigerian Batik Artist.

    ERIC Educational Resources Information Center

    LaDuke, Betty

    1987-01-01

    Chronicles the personal and professional life of Nike Twins Seven Seven (born 1951), a Nigerian batik artist, and her husband, Twins Seven Seven, a musician-artist, both of whom have received international acclaim. (BJV)

  14. Diagnosis of twin-to-twin transfusion syndrome, selective fetal growth restriction, twin anaemia-polycythaemia sequence, and twin reversed arterial perfusion sequence.

    PubMed

    Sueters, Marieke; Oepkes, Dick

    2014-02-01

    Monochorionic twin pregnancies are well known to be at risk for a variety of severe complications, a true challenge for the maternal-fetal medicine specialist. With current standards of care, monochorionicity should be established in the first trimester. Subsequently, frequent monitoring using the appropriate diagnostic tools, and in-depth knowledge about the pathophysiology of all possible clinical presentations of monochorionic twin abnormalities, should lead to timely recognition, and appropriate management. Virtually all unique diseases found in monochorionic twins are directly related to placental angio-architecture. This, however, cannot be established reliably before birth. The clinician needs to be aware of the definitions and symptoms of twin-to twin transfusion syndrome, selective fetal growth restriction, twin anaemia-polycythaemia sequence, and twin reversed arterial perfusion sequence, to be able to recognise each disease and take the required action. In this chapter, we address current standards on correct and timely diagnoses of severe complications of monochorionic twin pregnancies.

  15. Monozygotic twins discordant for trisomy 13.

    PubMed

    Ramsey, K Wong; Slavin, T P; Graham, G; Hirata, G I; Balaraman, V; Seaver, L H

    2012-04-01

    Monozygotic twins with discordant karyotypes are rare. We report a case of monozygotic twins discordant for trisomy 13 by amniocyte karyotypes. Ultrasound revealed multiple congenital anomalies in Twin A (47,XY,+13), none in Twin B (46,XY), and monochorionic-diamniotic placentation. Zygosity testing performed both prenatally and after birth supported monozygosity. Twin A died in the neontal period. Twin B survived and had normal physical examination, but peripheral blood karyotype revealed 20% mosaicism for trisomy 13. Monochorionic-diamniontic placentation with vascular anastomoses was confirmed by pathological examination. In this paper, we discuss the various mechanisms by which monozygotic twins may have discordant karyotypes. The surviving twin, structurally and developmentally normal at 6 months of age, will be monitored for potential complications of uniparental disomy of chromosome 13 and trisomy 13 mosaicism.

  16. A Little Twin Higgs Model

    SciTech Connect

    Goh, Hock-Seng; Goh, Hock-Seng; Krenke, Christopher A.

    2007-07-25

    We present a twin Higgs model based on left-right symmetry with a tree level quartic. This is made possible by extending the symmetry of the model to include two Z_2 parities, each of which is sufficient to protect the Higgs from getting a quadratically divergent mass squared. Although both parities are brokenexplicitly, the symmetries that protect the Higgs from getting a quadratically divergent mass are broken only collectively. The quadratic divergences of the Higgs mass are thus still protected at one loop. We find that the fine-tuning in this model is reduced substantially compared to the original left-right twin Higgs model. This mechanism can also be applied to the mirror twin Higgs model to get a significant reduction of the fine-tuning, while keeping the mirror photon massless.

  17. 180. Photocopy of Photograph, Twin Falls Canal Company. E. Pettygro, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    180. Photocopy of Photograph, Twin Falls Canal Company. E. Pettygro, Photographer, date unknown. BLASTING TWIN FALLS CANAL, TWIN FALLS COUNTY; BLASTING COTTONWOOD AREA TO REPLACE FLUME BY RUNNING HIGH LINE THROUGH SOLID ROCK. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  18. Impact of Twin-to-Twin Transfusion Syndrome, Preterm Birth, and Vision Loss on Development

    ERIC Educational Resources Information Center

    Celeste, Marie

    2005-01-01

    This study compared the developmental outcomes of twin boys (one who is blind and one who is sighted) who were born prematurely and diagnosed with twin-to-twin transfusion syndrome (TTTS) at age 24 months. The results indicate a disparity in the developmental outcomes of the twins. Although the medical risk factors that are associated with TTTS…

  19. GENE NETWORK EFFECTS ON BRAIN MICROSTRUCTURE AND INTELLECTUAL PERFORMANCE IDENTIFIED IN 472 TWINS

    PubMed Central

    Chiang, Ming-Chang; Barysheva, Marina; McMahon, Katie L.; de Zubicaray, Greig I.; Johnson, Kori; Montgomery, Grant W.; Martin, Nicholas G.; Toga, Arthur W.; Wright, Margaret J.; Shapshak, Paul; Thompson, Paul M.

    2012-01-01

    A major challenge in neuroscience is finding which genes affect brain integrity, connectivity, and intellectual function. Discovering influential genes holds vast promise for neuroscience, but typical genome-wide searches assess around one million genetic variants one-by-one, leading to intractable false positive rates, even with vast samples of subjects. Even more intractable is the question of which genes interact and how they work together to affect brain connectivity. Here we report a novel approach that discovers which genes contribute to brain wiring and fiber integrity at all pairs of points in a brain scan. We studied genetic correlations between thousands of points in human brain images from 472 twins and their non-twin siblings (mean age: 23.7±2.1 SD years; 193 M/279 F). We combined clustering with genome-wide scanning to find brain systems with common genetic determination. We then filtered the image in a new way to boost power to find causal genes. Using network analysis, we found a network of genes that affect brain wiring in healthy young adults. Our new strategy makes it more computationally tractable to discover genes that affect brain integrity. The gene network showed small-world and scale-free topologies, suggesting efficiency in genetic interactions, and resilience to network disruption. Genetic variants at hubs of the network influence intellectual performance by modulating associations between performance intelligence quotient (IQ) and the integrity of major white matter tracts, such as the callosal genu and splenium, cingulum, optic radiations, and the superior longitudinal fasciculus. PMID:22723713

  20. Differential Parenting and Risk for Psychopathology: A Monozygotic Twin Difference Approach

    PubMed Central

    Long, E.C.; Aggen, S. H.; Gardner, C.; Kendler, K. S.

    2015-01-01

    Purpose Consistent and non-specific associations have been found between parenting style and major depression, anxiety disorders, and externalizing behavior. Although often considered part of twins’ shared environment, parenting can also be conceptualized as non-shared environment. Non-shared environmental influences have important effects on development but are difficult to test and sort out because of the possible confounding effects of gene-environment interactions and evocative gene-environment correlations. The MZ differences approach is one way to analytically investigate non-shared environment. Methods The aim of the present study is to use the MZ differences approach to investigate the relationship between differential parenting among 1,303 twin pairs (mean age 36.69 +/− 8.56) and differences in total symptom counts of major depression (MD), generalized anxiety disorder (GAD), conduct disorder (CD), and anti-social behavior (ASB) during adulthood. Results Although effect sizes tended to be small, a number of results were significantly different from zero. Perceived differences in parental coldness was positively associated with internalizing disorders. Differences in protectiveness were negatively associated with MD, GAD, and ASB. Differences in authoritarianism were positively associated with MD and CD, but negatively associated with ASB. Conclusions Perceived differences in parenting style are associated with differences in MD, GAD, CD, and ASB outcomes in a sample of MZ twins. Despite the lack of a basis for making causal inferences about parenting style and psychopathology, these results are suggestive of such a relationship and show that non-shared environmental influence of parenting does in some cases significantly predict adult psychopathology. PMID:25940788

  1. Genetic and environmental effects on the bone development of the hand and wrist in Chinese young twins.

    PubMed

    Dong, Li Yan; Tan, Ji Bin; Zhao, Jing Lan; Jiang, Fa Chun; Tian, Xiao Cao; Ning, Feng; Wang, Shao Jie; Zhang, Dong Feng; Pang, Zeng Chang; Zhao, Zhong Tang

    2015-03-01

    We assessed genetic and environmental effects on bone development of the hand and wrist, and on key anthropometric measures in Chinese young twins. In total, 139 monozygotic and 95 dizygotic twin pairs aged from 5 to 18 years were recruited. The twin correlations of total hand and wrist scores for monozygotic (MZ) and dizygotic (DZ) twins were 0.71 and 0.36, respectively. Bivariate model analysis showed moderate genetic correlations only for total skeletal maturity vs. weight and total skeletal maturity vs. waist circumference (r, 0.51 and 0.46, respectively). Our findings demonstrated that genetic factors played important roles in bone development of the hand and wrist in Chinese young twins, and that these genetic effects might be distinct from those influencing anthropometric measures. PMID:25800451

  2. Brain-derived neurotrophic factor infusion delays amygdala and perforant path kindling without affecting paired-pulse measures of neuronal inhibition in adult rats.

    PubMed

    Osehobo, P; Adams, B; Sazgar, M; Xu, Y; Racine, R J; Fahnestock, M

    1999-01-01

    Kindling is an animal model of human temporal lobe epilepsy in which excitability in limbic structures is permanently enhanced by repeated stimulations. Kindling also increases the expression of nerve growth factor, brain-derived neurotrophic factor, and brain-derived neurotrophic factor receptor messenger RNAs in both the hippocampus and cerebral cortex and causes structural changes in the hippocampus including hilar hypertrophy. We have recently shown that intraventricular nerve growth factor infusion enhances the development of kindling, whereas blocking nerve growth factor activity retards amygdaloid kindling. Furthermore, we have shown that nerve growth factor protects against kindling-induced hilar hypertrophy. The physiological role of brain-derived neurotrophic factor in kindling is not as clear. Acute injection of brain-derived neurotrophic factor increases neuronal excitability and causes seizures, whereas chronic brain-derived neurotrophic factor infusion in rats slows hippocampal kindling. In agreement with the latter, we show here that intrahilar brain-derived neurotrophic factor infusion delays amygdala and perforant path kindling. In addition, we show that brain-derived neurotrophic factor, unlike nerve growth factor, does not protect against kindling-induced increases in hilar area. To test the hypothesis that brain-derived neurotrophic factor suppresses kindling by increasing inhibition above normal levels, we performed paired-pulse measures in the perforant path-dentate gyrus pathway. Brain-derived neurotrophic factor infused into the hippocampus had no effect on the stimulus intensity function (input/output curves); there was also no significant effect on paired-pulse inhibition. We then kindled the perforant path 10 days after the end of brain-derived neurotrophic factor treatment. Once again, kindling was retarded, showing that the brain-derived neurotrophic factor effect is long-lasting. These results indicate that prolonged in vivo infusion

  3. Intrauterine environment and cognitive development in young twins.

    PubMed

    Antoniou, E E; Fowler, T; Thiery, E; Southwood, T R; van Gestel, S; Jacobs, N; Vlietinck, R; van Os, J; Rijsdijk, F V; Derom, C; Zeegers, M P

    2013-12-01

    Intrauterine factors important for cognitive development, such as birth weight, chorionicity and umbilical cord characteristics were investigated. A total of 663 twin pairs completed the Wechsler Intelligence Scale for Children-Revised and scores were available for Performance, Verbal and Total Intelligence Quotient (IQ). The intrauterine factors examined were birth weight, placental weight and morphology, cord knots, cord length and cord insertion. IQ scores for the varying levels of the intrauterine markers adjusting for gender and gestational age were calculated. The heritability of IQ and the association between IQ and intrauterine environment were examined. Twins with lower birth weight and cord knots had lower IQ scores. The aetiology of IQ is largely distinct from that of birth weight and cord knots, and non-shared environment may influence the observed relationships.

  4. Speaking fundamental frequency in monozygotic and dizygotic twins.

    PubMed

    Debruyne, Frans; Decoster, Wivine; Van Gijsel, Annemie; Vercammen, Julie

    2002-12-01

    The speaking fundamental frequency (SFF) and the intraindividual variation of the SFF during the reading of a Dutch standard text were measured in 30 female monozygotic twins (MT) and 30 dizygotic twins (DT), aged 15-29 years. A control group was created that consisted of 30 nonrelated paired individuals of equal age. Studying the intrapair correlation coefficients it seemed that the SFF was similar to a greater degree in MT and to a lesser degree in DT, while there was no correlation at all in nonrelated peers. These results are compatible with a genetic basis for the SFF. On the other hand, the intraindividual variation of the SFF was highly similar in MT and in DT (but not in nonrelated peers), so that for this parameter it was not possible to discern the influences of genetic disposition and shared environment. PMID:12512633

  5. Twins reunited: scientific and personal perspectives/twin research studies: multiple birth effects on IQ and body size; life style, muscles, and metabolism; monochorionic dizygotic twin with blood chimerism; amniocentesis for twins/twins in the media: identical doctors; freedom fighter for twins; twin scholarships; Auguste and Jean-Felix Piccard; twins born apart.

    PubMed

    Segal, Nancy L; Mulligan, Christy A

    2014-04-01

    A reunion of 38-year-old female monozygotic twins took place in Daegu, South Korea, on January 14, 2014. Scientific and personal perspectives on this extraordinary event are provided. A review of timely twin research follows, covering the effects of multiple births on IQ and body size, lifestyle and physical fitness associations, a rare case of a dizygotic twin with blood chimerism and definitional issues surrounding amniocentesis-related loss in multiple birth pregnancies. Interesting and informative mention of twins in the media includes twin doctors, a twin freedom fighter, the availability of college scholarships for twins, a new book about the Piccard family (two of whose members were twins), and co-twins born before and after the new year. A follow-up to a previous mention of identical twin biatheletes is also provided. PMID:24589452

  6. Genetics and the environment affect the relationship between depression and low back pain: a co-twin control study of Spanish twins.

    PubMed

    Pinheiro, Marina B; Ferreira, Manuela L; Refshauge, Kathryn; Colodro-Conde, Lucía; Carrillo, Eduvigis; Hopper, John L; Ordoñana, Juan R; Ferreira, Paulo H

    2015-03-01

    Although the co-occurrence of low back pain (LBP) and depression is common, the nature of this association remains unclear. We aimed to investigate whether symptoms of depression are associated with LBP after adjusting for various confounders, including genetics. We used cross-sectional data from 2148 twins from the Murcia Twin Registry, Spain. All twins answered questions about lifetime prevalence of LBP (outcome variable) and symptoms of depression, collected through two instruments, deriving 3 measures: (1) self-report feelings of depression and anxiety; (2) state depression, and (3) trait depression. First, associations were investigated using logistic regression analysis of the total sample. We performed subsequent matched within-pair twin case-control analyses with all complete twin pairs discordant for LBP regardless of zygosity, and separately for dizygotic and monozygotic pairs. This sequential analysis allows for more precise estimates of the relationship between variables, as in each step, the impact of early shared environment and genetics is further considered. Symptoms of depression and anxiety were associated with higher prevalence of LBP in the total sample analysis (odds ratio [OR], 1.64; 95% confidence interval [CI], 1.31-2.05), and this relationship was stronger in the subsequent case-control analysis (OR, 1.74; 95% CI, 1.13-2.69) and dizygotic case-control analysis (OR, 2.39; 95% CI, 1.39-4.08) but disappeared when the analysis was conducted for monozygotic twins (OR, 0.92; 95% CI, 0.42-2.05). A similar pattern was found for state and trait depression. The depression-LBP relationship disappears when high levels of control for confounding factors are applied and seems to be driven by genetic or environmental factors that influence both conditions. PMID:25679471

  7. Genetics and the environment affect the relationship between depression and low back pain: a co-twin control study of Spanish twins.

    PubMed

    Pinheiro, Marina B; Ferreira, Manuela L; Refshauge, Kathryn; Colodro-Conde, Lucía; Carrillo, Eduvigis; Hopper, John L; Ordoñana, Juan R; Ferreira, Paulo H

    2015-03-01

    Although the co-occurrence of low back pain (LBP) and depression is common, the nature of this association remains unclear. We aimed to investigate whether symptoms of depression are associated with LBP after adjusting for various confounders, including genetics. We used cross-sectional data from 2148 twins from the Murcia Twin Registry, Spain. All twins answered questions about lifetime prevalence of LBP (outcome variable) and symptoms of depression, collected through two instruments, deriving 3 measures: (1) self-report feelings of depression and anxiety; (2) state depression, and (3) trait depression. First, associations were investigated using logistic regression analysis of the total sample. We performed subsequent matched within-pair twin case-control analyses with all complete twin pairs discordant for LBP regardless of zygosity, and separately for dizygotic and monozygotic pairs. This sequential analysis allows for more precise estimates of the relationship between variables, as in each step, the impact of early shared environment and genetics is further considered. Symptoms of depression and anxiety were associated with higher prevalence of LBP in the total sample analysis (odds ratio [OR], 1.64; 95% confidence interval [CI], 1.31-2.05), and this relationship was stronger in the subsequent case-control analysis (OR, 1.74; 95% CI, 1.13-2.69) and dizygotic case-control analysis (OR, 2.39; 95% CI, 1.39-4.08) but disappeared when the analysis was conducted for monozygotic twins (OR, 0.92; 95% CI, 0.42-2.05). A similar pattern was found for state and trait depression. The depression-LBP relationship disappears when high levels of control for confounding factors are applied and seems to be driven by genetic or environmental factors that influence both conditions.

  8. Pairing Learners in Pair Work Activity

    ERIC Educational Resources Information Center

    Storch, Neomy; Aldosari, Ali

    2013-01-01

    Although pair work is advocated by major theories of second language (L2) learning and research findings suggest that pair work facilitates L2 learning, what is unclear is how to best pair students in L2 classes of mixed L2 proficiency. This study investigated the nature of pair work in an English as a Foreign Language (EFL) class in a college in…

  9. Speech and Language Delays in Identical Twins.

    ERIC Educational Resources Information Center

    Bentley, Pat

    Following a literature review on speech and language development of twins, case studies are presented of six sets of identical twins screened for entrance into kindergarten. Five sets of the twins and one boy from the sixth set failed to pass the screening test, particularly the speech and language section, and were referred for therapy to correct…

  10. On Teaching About Twins and Time

    ERIC Educational Resources Information Center

    Hewitt, Paul G.

    1973-01-01

    Discusses a four-step instructional presentation in which the twin on the earth is demonstrated older than the twin aboard a spaceship on the basis of the relativistic Doppler effect. Concludes that both twins can meet again at the same place in space at the expense of time. (CC)

  11. Identical twin discordance for the Brachmann-de Lange syndrome revisited

    SciTech Connect

    Carakushansky, G.; Goncalves, M.R.; Kahn, E.

    1996-06-14

    The only known twin pair evidently discordantly affected for the BDLS (Brachmann-de Lange syndrome) and who had been considered monozygotic (MZ) based on blood analysis remained a problem because biological zygosity determination needed further typing. In this report we review the clinical findings of this pair of twins at the age of 20. The use of DNA fingerprinting with three multilocus probes, F10, DNT24, and 33.6, allowed us to present evidence of monozygosity with a high degree of certainty. The significance of this confirmation of discordance in determining the cause of BDLS is discussed. Intensive comparative genomic studies of the discordant twin sisters may be useful to unravel the molecular genetics of this enigmatic pattern of malformation. 21 refs., 2 figs.

  12. Paired comparisons of nonlinear frequency compression, extended bandwidth, and restricted bandwidth hearing-aid processing for children and adults with hearing loss

    PubMed Central

    Brennan, Marc A.; McCreery, Ryan; Kopun, Judy; Hoover, Brenda; Alexander, Joshua; Lewis, Dawna; Stelmachowicz, Patricia G.

    2014-01-01

    Background Preference for speech and music processed with nonlinear frequency compression and two controls (restricted and extended bandwidth hearing-aid processing) was examined in adults and children with hearing loss. Purpose Determine if stimulus type (music, sentences), age (children, adults) and degree of hearing loss influence listener preference for nonlinear frequency compression, restricted bandwidth and extended bandwidth. Research Design Within-subject, quasi-experimental study. Using a round-robin procedure, participants listened to amplified stimuli that were 1) frequency-lowered using nonlinear frequency compression, 2) low-pass filtered at 5 kHz to simulate the restricted bandwidth of conventional hearing aid processing, or 3) low-pass filtered at 11 kHz to simulate extended bandwidth amplification. The examiner and participants were blinded to the type of processing. Using a two-alternative forced-choice task, participants selected the preferred music or sentence passage. Study Sample Sixteen children (8–16 years) and 16 adults (19–65 years) with mild-to-severe sensorineural hearing loss. Intervention All subjects listened to speech and music processed using a hearing-aid simulator fit to the Desired Sensation Level algorithm v.5.0a (Scollie et al, 2005). Results Children and adults did not differ in their preferences. For speech, participants preferred extended bandwidth to both nonlinear frequency compression and restricted bandwidth. Participants also preferred nonlinear frequency compression to restricted bandwidth. Preference was not related to degree of hearing loss. For music, listeners did not show a preference. However, participants with greater hearing loss preferred nonlinear frequency compression to restricted bandwidth more than participants with less hearing loss. Conversely, participants with greater hearing loss were less likely to prefer extended bandwidth to restricted bandwidth. Conclusion Both age groups preferred access to

  13. Comparison of Genomic and Epigenomic Expression in Monozygotic Twins Discordant for Rett Syndrome.

    PubMed

    Miyake, Kunio; Yang, Chunshu; Minakuchi, Yohei; Ohori, Kenta; Soutome, Masaki; Hirasawa, Takae; Kazuki, Yasuhiro; Adachi, Noboru; Suzuki, Seiko; Itoh, Masayuki; Goto, Yu-Ichi; Andoh, Tomoko; Kurosawa, Hiroshi; Oshimura, Mitsuo; Sasaki, Masayuki; Toyoda, Atsushi; Kubota, Takeo

    2013-01-01

    Monozygotic (identical) twins have been widely used in genetic studies to determine the relative contributions of heredity and the environment in human diseases. Discordance in disease manifestation between affected monozygotic twins has been attributed to either environmental factors or different patterns of X chromosome inactivation (XCI). However, recent studies have identified genetic and epigenetic differences between monozygotic twins, thereby challenging the accepted experimental model for distinguishing the effects of nature and nurture. Here, we report the genomic and epigenomic sequences in skin fibroblasts of a discordant monozygotic twin pair with Rett syndrome, an X-linked neurodevelopmental disorder characterized by autistic features, epileptic seizures, gait ataxia and stereotypical hand movements. The twins shared the same de novo mutation in exon 4 of the MECP2 gene (G269AfsX288), which was paternal in origin and occurred during spermatogenesis. The XCI patterns in the twins did not differ in lymphocytes, skin fibroblasts, and hair cells (which originate from ectoderm as does neuronal tissue). No reproducible differences were detected between the twins in single nucleotide polymorphisms (SNPs), insertion-deletion polymorphisms (indels), or copy number variations. Differences in DNA methylation between the twins were detected in fibroblasts in the upstream regions of genes involved in brain function and skeletal tissues such as Mohawk Homeobox (MKX), Brain-type Creatine Kinase (CKB), and FYN Tyrosine Kinase Protooncogene (FYN). The level of methylation in these upstream regions was inversely correlated with the level of gene expression. Thus, differences in DNA methylation patterns likely underlie the discordance in Rett phenotypes between the twins. PMID:23805272

  14. Four twins for a paradox: on "sensitive" twins and the biological counterpart of the "twin paradox".

    PubMed

    Ascioti, Fortunato A

    2009-03-01

    Monozygotic twin (MZT) epigenetic development, i.e., aging, diverges largely in time despite the initially very small genetic differences between MZTs. This fact is interpreted as a "sensitivity to initial conditions" phenomenon, a common property of either deterministic or stochastic chaotic systems. Some of the biotheoretical implications stemming from this empirical observation are briefly discussed here, while an actual measure of MZT epigenetic time divergence is given through an estimate of the (Stochastic) Lyapunov exponents (LEs) (i.e., the rate of exponential time divergence). These results suggest a reconsideration of the Langevin-Einstein thought experiment known as the "twin paradox." At least four twins are necessary in order to take into account the inertially independent divergent aging described here. Alternatively, LE estimates, like those given here, should be used. Finally suggested in the actual special-relativity experiments is the replacement of clocks with some nonlinear (chaotic) forced oscillator. PMID:19334992

  15. Four twins for a paradox: On ``sensitive'' twins and the biological counterpart of the ``twin paradox''

    NASA Astrophysics Data System (ADS)

    Ascioti, Fortunato A.

    2009-03-01

    Monozygotic twin (MZT) epigenetic development, i.e., aging, diverges largely in time despite the initially very small genetic differences between MZTs. This fact is interpreted as a "sensitivity to initial conditions" phenomenon, a common property of either deterministic or stochastic chaotic systems. Some of the biotheoretical implications stemming from this empirical observation are briefly discussed here, while an actual measure of MZT epigenetic time divergence is given through an estimate of the (Stochastic) Lyapunov exponents (LEs) (i.e., the rate of exponential time divergence). These results suggest a reconsideration of the Langevin-Einstein thought experiment known as the "twin paradox." At least four twins are necessary in order to take into account the inertially independent divergent aging described here. Alternatively, LE estimates, like those given here, should be used. Finally suggested in the actual special-relativity experiments is the replacement of clocks with some nonlinear (chaotic) forced oscillator.

  16. Epigenetic differences in monozygotic twins discordant for major depressive disorder.

    PubMed

    Malki, K; Koritskaya, E; Harris, F; Bryson, K; Herbster, M; Tosto, M G

    2016-01-01

    Although monozygotic (MZ) twins share the majority of their genetic makeup, they can be phenotypically discordant on several traits and diseases. DNA methylation is an epigenetic mechanism that can be influenced by genetic, environmental and stochastic events and may have an important impact on individual variability. In this study we explored epigenetic differences in peripheral blood samples in three MZ twin studies on major depressive disorder (MDD). Epigenetic data for twin pairs were collected as part of a previous study using 8.1-K-CpG microarrays tagging DNA modification in white blood cells from MZ twins discordant for MDD. Data originated from three geographical regions: UK, Australia and the Netherlands. Ninety-seven MZ pairs (194 individuals) discordant for MDD were included. Different methods to address non independently-and-identically distributed (non-i.i.d.) data were evaluated. Machine-learning methods with feature selection centered on support vector machine and random forest were used to build a classifier to predict cases and controls based on epivariations. The most informative variants were mapped to genes and carried forward for network analysis. A mixture approach using principal component analysis (PCA) and Bayes methods allowed to combine the three studies and to leverage the increased predictive power provided by the larger sample. A machine-learning algorithm with feature reduction classified affected from non-affected twins above chance levels in an independent training-testing design. Network analysis revealed gene networks centered on the PPAR-γ (NR1C3) and C-MYC gene hubs interacting through the AP-1 (c-Jun) transcription factor. PPAR-γ (NR1C3) is a drug target for pioglitazone, which has been shown to reduce depression symptoms in patients with MDD. Using a data-driven approach we were able to overcome challenges of non-i.i.d. data when combining epigenetic studies from MZ twins discordant for MDD. Individually, the studies yielded

  17. Epigenetic differences in monozygotic twins discordant for major depressive disorder

    PubMed Central

    Malki, K; Koritskaya, E; Harris, F; Bryson, K; Herbster, M; Tosto, M G

    2016-01-01

    Although monozygotic (MZ) twins share the majority of their genetic makeup, they can be phenotypically discordant on several traits and diseases. DNA methylation is an epigenetic mechanism that can be influenced by genetic, environmental and stochastic events and may have an important impact on individual variability. In this study we explored epigenetic differences in peripheral blood samples in three MZ twin studies on major depressive disorder (MDD). Epigenetic data for twin pairs were collected as part of a previous study using 8.1-K-CpG microarrays tagging DNA modification in white blood cells from MZ twins discordant for MDD. Data originated from three geographical regions: UK, Australia and the Netherlands. Ninety-seven MZ pairs (194 individuals) discordant for MDD were included. Different methods to address non independently-and-identically distributed (non-i.i.d.) data were evaluated. Machine-learning methods with feature selection centered on support vector machine and random forest were used to build a classifier to predict cases and controls based on epivariations. The most informative variants were mapped to genes and carried forward for network analysis. A mixture approach using principal component analysis (PCA) and Bayes methods allowed to combine the three studies and to leverage the increased predictive power provided by the larger sample. A machine-learning algorithm with feature reduction classified affected from non-affected twins above chance levels in an independent training-testing design. Network analysis revealed gene networks centered on the PPAR−γ (NR1C3) and C-MYC gene hubs interacting through the AP-1 (c-Jun) transcription factor. PPAR−γ (NR1C3) is a drug target for pioglitazone, which has been shown to reduce depression symptoms in patients with MDD. Using a data-driven approach we were able to overcome challenges of non-i.i.d. data when combining epigenetic studies from MZ twins discordant for MDD. Individually, the studies

  18. Epigenetic differences in monozygotic twins discordant for major depressive disorder.

    PubMed

    Malki, K; Koritskaya, E; Harris, F; Bryson, K; Herbster, M; Tosto, M G

    2016-06-14

    Although monozygotic (MZ) twins share the majority of their genetic makeup, they can be phenotypically discordant on several traits and diseases. DNA methylation is an epigenetic mechanism that can be influenced by genetic, environmental and stochastic events and may have an important impact on individual variability. In this study we explored epigenetic differences in peripheral blood samples in three MZ twin studies on major depressive disorder (MDD). Epigenetic data for twin pairs were collected as part of a previous study using 8.1-K-CpG microarrays tagging DNA modification in white blood cells from MZ twins discordant for MDD. Data originated from three geographical regions: UK, Australia and the Netherlands. Ninety-seven MZ pairs (194 individuals) discordant for MDD were included. Different methods to address non independently-and-identically distributed (non-i.i.d.) data were evaluated. Machine-learning methods with feature selection centered on support vector machine and random forest were used to build a classifier to predict cases and controls based on epivariations. The most informative variants were mapped to genes and carried forward for network analysis. A mixture approach using principal component analysis (PCA) and Bayes methods allowed to combine the three studies and to leverage the increased predictive power provided by the larger sample. A machine-learning algorithm with feature reduction classified affected from non-affected twins above chance levels in an independent training-testing design. Network analysis revealed gene networks centered on the PPAR-γ (NR1C3) and C-MYC gene hubs interacting through the AP-1 (c-Jun) transcription factor. PPAR-γ (NR1C3) is a drug target for pioglitazone, which has been shown to reduce depression symptoms in patients with MDD. Using a data-driven approach we were able to overcome challenges of non-i.i.d. data when combining epigenetic studies from MZ twins discordant for MDD. Individually, the studies yielded

  19. Spatiotemporal configuration dependent pairing of nerve events in dark-adapted human vision

    NASA Astrophysics Data System (ADS)

    Bouman, Maarten A.

    2002-02-01

    In the model presented here, in the dark any single quantum absorption in a rod or cone produces a subliminal excitation. Subliminal excitations from both halves of a twin unit pair in the retina for the perception of light from the stimulus. A twin unit contains either two red or two green cones. The twin units are intertwined in triples of two red units and one green unit in a hexagon called a trion. P satellite rods surround each cone, P being approximately proportional to the square of eccentricity. A successful pairing for light perception represents-through the points of time and locations of the creation of its partners in the retina-a direction event with two possible polarities and with the orientation of the elongated shape of the twin unit. The polarity of the event depends on which of the two partners arrives first at the twin's pairing facility. Simultaneous events and successive events with the same polarity in adjacent units that are aligned along one of the three orientations of the hexagonal retinal mosaic pair in the cortex for the perception of edge and of movement. Inter-twin pairing products of the three differently oriented sets of aligned twins are independent of each other and sum vectorially in the cortex. This system of three sub-retinas is called the retrinet. Two one-quantum excitations in any of a twin's receptors make the percept colored. The odd blue cone produces already a blue signal for a single one-quantum excitation. Intra-receptor pairing in a rod, a red cone and a green cone is for white, red, and green respectively. Red and green cone products of a trion cross-pair in the retina and produce a yellow signal. Red and green cone products of a hexagon of adjacent trions cross-pair in the cortex and produce a white signal. This large hexagon with a total of seven trions is called a persepton. After subliminal excitations in a twin have paired successfully, further subliminal receptor excitations in neighboring and aligned twins are

  20. NOTE: Increasing cardiac output and decreasing oxygenation sequence in pump twins of acardiac twin pregnancies

    NASA Astrophysics Data System (ADS)

    van Gemert, Martin J. C.; Umur, Asli; van den Wijngaard, Jeroen P. H. M.; Van Bavel, Ed; Vandenbussche, Frank P. H. A.; Nikkels, Peter G. J.

    2005-02-01

    An acardiac twin pregnancy is a rare but serious complication of monochorionic twinning and consists of an acardiac twin and a pump twin. The acardiac twin is a severely malformed fetus that lacks most organs, particularly a heart, but grows during pregnancy because it is perfused by the developmentally normal pump twin via a set of arterioarterial and venovenous placental anastomoses. Pump twins die intrauterine or neonatally in about 50% of the cases. Because the effects of an acardiac mass on the pump twin's development are incompletely known, methods for outcome prognosis are currently not available. We sought to derive simple relations for the pump twin's excess cardiac output and decreased oxygenation and to use available clinical cases for a preliminary test of the model. As a method, we used a theoretical flow model to represent the fetoplacental circulation of an acardiac twin pregnancy and estimated blood deoxygenation and reoxygenation following perfusion of the two bodies and placentas, respectively. The results show the pump twin's excess cardiac output and decrease of venous oxygen saturation to depend on the ratio of pump twin to acardiac twin umbilical blood flow, whose ratio can be measured by ultrasonography. The clinical cases show a decreasing umbilical flow ratio with gestation. In conclusion, prospective serial study is necessary to test whether measurement of umbilical flow ratios allows monitoring the pump twin's pathophysiologic development, possibly resulting in a guideline for prognosis of pump twin survival.