Construction of physical maps for the sex-specific regions of papaya sex chromosomes.

PubMed

Na, Jong-Kuk; Wang, Jianping; Murray, Jan E; Gschwend, Andrea R; Zhang, Wenli; Yu, Qingyi; Navajas-Pérez, Rafael; Feltus, F Alex; Chen, Cuixia; Kubat, Zdenek; Moore, Paul H; Jiang, Jiming; Paterson, Andrew H; Ming, Ray

2012-05-08

Papaya is a major fruit crop in tropical and subtropical regions worldwide. It is trioecious with three sex forms: male, female, and hermaphrodite. Sex determination is controlled by a pair of nascent sex chromosomes with two slightly different Y chromosomes, Y for male and Yh for hermaphrodite. The sex chromosome genotypes are XY (male), XYh (hermaphrodite), and XX (female). The papaya hermaphrodite-specific Yh chromosome region (HSY) is pericentromeric and heterochromatic. Physical mapping of HSY and its X counterpart is essential for sequencing these regions and uncovering the early events of sex chromosome evolution and to identify the sex determination genes for crop improvement. A reiterate chromosome walking strategy was applied to construct the two physical maps with three bacterial artificial chromosome (BAC) libraries. The HSY physical map consists of 68 overlapped BACs on the minimum tiling path, and covers all four HSY-specific Knobs. One gap remained in the region of Knob 1, the only knob structure shared between HSY and X, due to the lack of HSY-specific sequences. This gap was filled on the physical map of the HSY corresponding region in the X chromosome. The X physical map consists of 44 BACs on the minimum tiling path with one gap remaining in the middle, due to the nature of highly repetitive sequences. This gap was filled on the HSY physical map. The borders of the non-recombining HSY were defined genetically by fine mapping using 1460 F2 individuals. The genetically defined HSY spanned approximately 8.5 Mb, whereas its X counterpart extended about 5.4 Mb including a 900 Kb region containing the Knob 1 shared by the HSY and X. The 8.5 Mb HSY corresponds to 4.5 Mb of its X counterpart, showing 4 Mb (89%) DNA sequence expansion. The 89% increase of DNA sequence in HSY indicates rapid expansion of the Yh chromosome after genetic recombination was suppressed 2-3 million years ago. The genetically defined borders coincide with the common

The X chromosome of monotremes shares a highly conserved region with the eutherian and marsupial X chromosomes despite the absence of X chromosome inactivation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, J.M.; Spencer, J.A.; Graves, J.A.M.

1990-09-01

Eight genes, located on the long arm of the human X chromosome and present on the marsupial X chromosome, were mapped by in situ hybridization to the chromosomes of the platypus Ornithorhynchus anatinus, one of the three species of monotreme mammals. All were located on the X chromosome. The authors conclude that the long arm of the human X chromosome represents a highly conserved region that formed part of the X chromosome in a mammalian ancestor at least 150 million years ago. Since three of these genes are located on the long arm of the platypus X chromosome, which ismore » G-band homologous to the Y chromosome and apparently exempt from X chromosome inactivation, the conservation of this region has evidently not depended on isolation by X-Y chromosome differentiation and X chromosome inactivation.« less

Nucleolus organizer regions and B-chromosomes of wood mice (mammalia, rodentia, Apodemus)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boeskorov, G.G.; Kartavtseva, I.V.; Zagorodnyuk, I.V.

1995-02-01

Distribution of nucleolus organizer regions (NORs) in karyotypes was studied in 10 species of wood mice, including Apodemus flavicollis, A. sylvaticus, A. uralensis (=A. microps), A. fulvipectus (=A. falzfeini), A. ponticus, A. hyrcanicus, A. mystacinus, A. agrarius, A. peninsulae, and A. speciosus. Peculiarities of NOR location in karyotypes can be used in interspecific diagnostics of wood mice. Intraspecific polymorphism of A. sylvaticus, A. agrarius, and A. peninsulae in terms of the number of NORs and their localization in chromosomes can serve as evidence for karyological differentiation in certain populations of these species. The minimum number of active NORs in micemore » of the genus Apodemus is two to four. Two A. flavicollis wood mice with karyotypes containing one small acrocentric B-chromosome (2n = 49) were identified among animals captured in Estonia. In A. peninsulae, B-chromosomes were found among animals captured in the following regions: the vicinity of Kyzyl (one mouse with 17 microchromosomes, 2n = 65); the vicinity of Birakan (two mice with one metacentric chromosome each, 2n = 49); and in the Ussuri Nature Reserve (one mouse with five B-chromosomes, including three metacentric and two dotlike chromosomes; 2n = 53). In the latter animal, the presence of NORs on two metacentric B-chromosomes was revealed; this is the first case of identification of active NORs on extra chromosomes of mammals. 29 refs., 4 figs., 1 tab.« less

Sex chromosome loss and the pseudoautosomal region genes in hematological malignancies

PubMed Central

Weng, Stephanie; Stoner, Samuel A.; Zhang, Dong-Er

2016-01-01

Cytogenetic aberrations, such as chromosomal translocations, aneuploidy, and amplifications, are frequently detected in hematological malignancies. For many of the common autosomal aberrations, the mechanisms underlying their roles in cancer development have been well-characterized. On the contrary, although loss of a sex chromosome is observed in a broad range of hematological malignancies, how it cooperates in disease development is less understood. Nevertheless, it has been postulated that tumor suppressor genes reside on the sex chromosomes. Although the X and Y sex chromosomes are highly divergent, the pseudoautosomal regions are homologous between both chromosomes. Here, we review what is currently known about the pseudoautosomal region genes in the hematological system. Additionally, we discuss implications for haploinsufficiency of critical pseudoautosomal region sex chromosome genes, driven by sex chromosome loss, in promoting hematological malignancies. Because mechanistic studies on disease development rely heavily on murine models, we also discuss the challenges and caveats of existing models, and propose alternatives for examining the involvement of pseudoautosomal region genes and loss of a sex chromosome in vivo. With the widespread detection of loss of a sex chromosome in different hematological malignances, the elucidation of the role of pseudoautosomal region genes in the development and progression of these diseases would be invaluable to the field. PMID:27655702

Chromosomal microarray analysis as the first-tier test for the identification of pathogenic copy number variants in chromosome 9 pericentric regions and its challenge.

PubMed

Wang, Jia-Chi; Boyar, Fatih Z

2016-01-01

Chromosomal microarray analysis (CMA) has been recommended and practiced routinely in the large reference laboratories of U.S.A. as the first-tier test for the postnatal evaluation of individuals with intellectual disability, autism spectrum disorders, and/or multiple congenital anomalies. Using CMA as a diagnostic tool and without a routine setting of fluorescence in situ hybridization with labeled bacterial artificial chromosome probes (BAC-FISH) in the large reference laboratories becomes a challenge in the characterization of chromosome 9 pericentric region. This region has a very complex genomic structure and contains a variety of heterochromatic and euchromatic polymorphic variants. These variants were usually studied by G-banding, C-banding and BAC-FISH analysis. Chromosomal microarray analysis (CMA) was not recommended since it may lead to false positive results. Here, we presented a cohort of four cases, in which high-resolution CMA was used as the first-tier test or simultaneously with G-banding analysis on the proband to identify pathogenic copy number variants (CNVs) in the whole genome. CMA revealed large pathogenic CNVs from chromosome 9 in 3 cases which also revealed different G-banding patterns between the two chromosome 9 homologues. Although we demonstrated that high-resolution CMA played an important role in the identification of pathogenic copy number variants in chromosome 9 pericentric regions, the lack of BAC-FISH analysis or other useful tools renders significant challenges in the characterization of chromosome 9 pericentric regions. None; it is not a clinical trial, and the cases were retrospectively collected and analyzed.

[Utility of chromosome banding with ALU I enzyme for identifying methylated areas in breast cancer].

PubMed

Rojas-Atencio, Alicia; Yamarte, Leonard; Urdaneta, Karelis; Soto-Alvarez, Marisol; Alvarez Nava, Francisco; Cañizalez, Jenny; Quintero, Maribel; Atencio, Raquel; González, Richard

2012-12-01

Cancer is a group of disorders characterized by uncontrolled cell growth which is produced by two successive events: increased cell proliferation (tumor or neoplasia) and the invasive capacity of these cells (metastasis). DNA methylation is an epigenetic process which has been involved as an important pathogenic factor of cancer. DNA methylation participates in the regulation of gene expression, directly, by preventing the union of transcription factors, and indirectly, by promoting the "closed" structure of the chromatine. The objectives of this study were to identify hypermethyled chromosomal regions through the use of restriction Alu I endonuclease, and to relate cytogenetically these regions with tumor suppressive gene loci. Sixty peripheral blood samples of females with breast cancer were analyzed. Cell cultures were performed and cytogenetic spreads, previously digested with Alu I enzyme, were stained with Giemsa. Chromosomal centromeric and not centromeric regions were stained in 37% of cases. About 96% of stained hypermethyled chromosomal regions (1q, 2q, 6q) were linked with methylated genes associated with breast cancer. In addition, centromeric regions in chromosomes 3, 4, 8, 13, 14, 15 and 17, usually unstained, were found positive to digestion with Alu I enzime and Giemsa staining. We suggest the importance of this technique for the global visualization of the genome which can find methylated genes related to breast cancer, and thus lead to a specific therapy, and therefore a better therapeutic response.

Identification of a herpes simplex labialis susceptibility region on human chromosome 21.

PubMed

Hobbs, Maurine R; Jones, Brandt B; Otterud, Brith E; Leppert, Mark; Kriesel, John D

2008-02-01

Most of the United States population is infected with either herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2, or both. Reactivations of HSV-1 infection cause herpes simplex labialis (HSL; cold sores or fever blisters), which is the most common recurring viral infection in humans. To investigate the possibility of a human genetic component conferring resistance or susceptibility to cold sores (i.e., a HSL susceptibility gene), we conducted a genetic linkage analysis that included serotyping and phenotyping 421 individuals from 39 families enrolled in the Utah Genetic Reference Project. Linkage analysis identified a 2.5-Mb nonrecombinant region of interest on the long arm of human chromosome 21, with a multipoint logarithm of odds score of 3.9 noted near marker abmc65 (D21S409). Nonparametric linkage analysis of the data also provided strong evidence for linkage (P = .0005). This region of human chromosome 21 contains 6 candidate genes for herpes susceptibility. The development of frequent cold sores is associated with a region on the long arm of human chromosome 21. This region contains several candidate genes that could influence the frequency of outbreaks of HSL.

[Strategies to identify supernumerary chromosomal markers in constitutional cytogenetics].

PubMed

Douet-Guilbert, N; Basinko, A; Le Bris, M-J; Herry, A; Morel, F; De Braekeleer, M

2008-09-01

Supernumerary marker chromosomes (SMCs) are defined as extrastructurally abnormal chromosomes which origin and composition cannot be determined by conventional cytogenetics. SMCs are an heterogeneous group of abnormalities concerning all chromosomes with variable structure and size and are associated with phenotypic heterogeneity. The characterisation of SMCs is of utmost importance for genetic counselling. Different molecular techniques are used to identify chromosomal material present in markers such as 24-colour FISH (MFISH, SKY), centromere specific multicolour FISH (cenMFISH) and derivatives (acroMFISH, subcenMFISH), comparative genomic hybridisation (CGH), arrayCGH, and targeted FISH techniques (banding techniques, whole chromosome painting...). Based on the morphology of SMC with conventional cytogenetic and clinical data, we tried to set up different molecular strategies with all available techniques.

Physical mapping of the torsion dystonia region of human chromosome 9q34

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ozelius, L.J.; Hewett, J.; Shalish, C.

1994-09-01

Torsion dystonia is a syndrome characterized by loss of voluntary movements appearing as sustained muscle contractions and/or abnormal postures. The DYT1 gene is responsible for a subtype of torsion dystonia in which onset of symptoms tends to occur in a limb at an early age (mean 13 years) and to progress to a generalized state. Expression of the disease gene follows an autosomal dominant mode of inheritance with reduced penetrance. We initially mapped this gene to human chromosome 9q34 and have now defined its location to a < 1 cM region near the ASS locus based on historic recombination eventsmore » around a founder mutation in the Ashkenazic Jewish population. Using the CEPH YAC library and a chromosome 9 flow-sorted YAC library, we have generated a YAC contig spanning about 500 kb of this region. These YACs are being used to identify cosmids by direct hybridization to chromosome 9-specific cosmid libraries. Cosmids are being aligned by restriction digest patterns and by hybridization with oligonucleotide repeat probes. In addition, the cosmids are being {open_quotes}trapped{close_quotes} by exon amplification and these exons used to screen cDNA libraries. Thus far we have identified several candidate transcripts in this region.« less

The evolution of vertebrate somatostatin receptors and their gene regions involves extensive chromosomal rearrangements

PubMed Central

2012-01-01

Background Somatostatin and its related neuroendocrine peptides have a wide variety of physiological functions that are mediated by five somatostatin receptors with gene names SSTR1-5 in mammals. To resolve their evolution in vertebrates we have investigated the SSTR genes and a large number of adjacent gene families by phylogeny and conserved synteny analyses in a broad range of vertebrate species. Results We find that the SSTRs form two families that belong to distinct paralogons. We observe not only chromosomal similarities reflecting the paralogy relationships between the SSTR-bearing chromosome regions, but also extensive rearrangements between these regions in teleost fish genomes, including fusions and translocations followed by reshuffling through intrachromosomal rearrangements. These events obscure the paralogy relationships but are still tractable thanks to the many genomes now available. We have identified a previously unrecognized SSTR subtype, SSTR6, previously misidentified as either SSTR1 or SSTR4. Conclusions Two ancestral SSTR-bearing chromosome regions were duplicated in the two basal vertebrate tetraploidizations (2R). One of these ancestral SSTR genes generated SSTR2, -3 and -5, the other gave rise to SSTR1, -4 and -6. Subsequently SSTR6 was lost in tetrapods and SSTR4 in teleosts. Our study shows that extensive chromosomal rearrangements have taken place between related chromosome regions in teleosts, but that these events can be resolved by investigating several distantly related species. PMID:23194088

Supernumerary ring chromosome 17 identified by fluorescent in situ hybridization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fagan, K.; Edwards, M.

We present a patient with multiple anomalies and severe developmental delay. A small supernumerary ring chromosome was found in 40% of her lymphocyte cells at birth. The origin of the marker chromosome could not be determined by GTG banding, but fluorescent in situ hybridization (FISH) later identified the marker as deriving from chromosome 17. 20 refs., 2 figs., 1 tab.

A high-resolution genetic, physical, and comparative gene map of the doublefoot (Dbf) region of mouse chromosome 1 and the region of conserved synteny on human chromosome 2q35.

PubMed

Hayes, C; Rump, A; Cadman, M R; Harrison, M; Evans, E P; Lyon, M F; Morriss-Kay, G M; Rosenthal, A; Brown, S D

2001-12-01

The mouse doublefoot (Dbf) mutant exhibits preaxial polydactyly in association with craniofacial defects. This mutation has previously been mapped to mouse chromosome 1. We have used a positional cloning strategy, coupled with a comparative sequencing approach using available human draft sequence, to identify putative candidates for the Dbf gene in the mouse and in homologous human region. We have constructed a high-resolution genetic map of the region, localizing the mutation to a 0.4-cM (+/-0.0061) interval on mouse chromosome 1. Furthermore, we have constructed contiguous BAC/PAC clone maps across the mouse and human Dbf region. Using existing markers and additional sequence tagged sites, which we have generated, we have anchored the physical map to the genetic map. Through the comparative sequencing of these clones we have identified 35 genes within this interval, indicating that the region is gene-rich. From this we have identified several genes that are known to be differentially expressed in the developing mid-gestation mouse embryo, some in the developing embryonic limb buds. These genes include those encoding known developmental signaling molecules such as WNT proteins and IHH, and we provide evidence that these genes are candidates for the Dbf mutation.

Characterization of the OmyY1 region on the rainbow trout Y chromosome

USGS Publications Warehouse

Phillips, Ruth B.; DeKoning, Jenefer J.; Brunelli, Joseph P.; Faber-Hammond, Joshua J.; Hansen, John D.; Christensen, Kris A.; Renn, Suzy C.P.; Thorgaard, Gary H.

2013-01-01

We characterized the male-specific region on the Y chromosome of rainbow trout, which contains both sdY (the sex-determining gene) and the male-specific genetic marker, OmyY1. Several clones containing the OmyY1 marker were screened from a BAC library from a YY clonal line and found to be part of an 800 kb BAC contig. Using fluorescence in situ hybridization (FISH), these clones were localized to the end of the short arm of the Y chromosome in rainbow trout, with an additional signal on the end of the X chromosome in many cells. We sequenced a minimum tiling path of these clones using Illumina and 454 pyrosequencing. The region is rich in transposons and rDNA, but also appears to contain several single-copy protein-coding genes. Most of these genes are also found on the X chromosome; and in several cases sex-specific SNPs in these genes were identified between the male (YY) and female (XX) homozygous clonal lines. Additional genes were identified by hybridization of the BACs to the cGRASP salmonid 4x44K oligo microarray. By BLASTn evaluations using hypothetical transcripts of OmyY1-linked candidate genes as query against several EST databases, we conclude at least 12 of these candidate genes are likely functional, and expressed.

The sex-specific region of sex chromosomes in animals and plants.

PubMed

Gschwend, Andrea R; Weingartner, Laura A; Moore, Richard C; Ming, Ray

2012-01-01

Our understanding of the evolution of sex chromosomes has increased greatly in recent years due to a number of molecular evolutionary investigations in divergent sex chromosome systems, and these findings are reshaping theories of sex chromosome evolution. In particular, the dynamics of the sex-determining region (SDR) have been demonstrated by recent findings in ancient and incipient sex chromosomes. Radical changes in genomic structure and gene content in the male specific region of the Y chromosome between human and chimpanzee indicated rapid evolution in the past 6 million years, defying the notion that the pace of evolution in the SDR was fast at early stages but slowed down overtime. The chicken Z and the human X chromosomes appeared to have acquired testis-expressed genes and expanded in intergenic regions. Transposable elements greatly contributed to SDR expansion and aided the trafficking of genes in the SDR and its X or Z counterpart through retrotransposition. Dosage compensation is not a destined consequence of sex chromosomes as once thought. Most X-linked microRNA genes escape silencing and are expressed in testis. Collectively, these findings are challenging many of our preconceived ideas of the evolutionary trajectory and fates of sex chromosomes.

Identification of chromosome 7 inversion breakpoints in an autistic family narrows candidate region for autism susceptibility.

PubMed

Cukier, Holly N; Skaar, David A; Rayner-Evans, Melissa Y; Konidari, Ioanna; Whitehead, Patrice L; Jaworski, James M; Cuccaro, Michael L; Pericak-Vance, Margaret A; Gilbert, John R

2009-10-01

Chromosomal breaks and rearrangements have been observed in conjunction with autism and autistic spectrum disorders. A chromosomal inversion has been previously reported in autistic siblings, spanning the region from approximately 7q22.1 to 7q31. This family is distinguished by having multiple individuals with autism and associated disabilities. The region containing the inversion has been strongly implicated in autism by multiple linkage studies, and has been particularly associated with language defects in autism as well as in other disorders with language components. Mapping of the inversion breakpoints by FISH has localized the inversion to the region spanning approximately 99-108.75 Mb of chromosome 7. The proximal breakpoint has the potential to disrupt either the coding sequence or regulatory regions of a number of cytochrome P450 genes while the distal region falls in a relative gene desert. Copy number variant analysis of the breakpoint regions detected no duplication or deletion that could clearly be associated with disease status. Association analysis in our autism data set using single nucleotide polymorphisms located near the breakpoints showed no significant association with proximal breakpoint markers, but has identified markers near the distal breakpoint ( approximately 108-110 Mb) with significant associations to autism. The chromosomal abnormality in this family strengthens the case for an autism susceptibility gene in the chromosome 7q22-31 region and targets a candidate region for further investigation.

Chromosome specific repetitive DNA sequences

DOEpatents

Moyzis, Robert K.; Meyne, Julianne

1991-01-01

A method is provided for determining specific nucleotide sequences useful in forming a probe which can identify specific chromosomes, preferably through in situ hybridization within the cell itself. In one embodiment, chromosome preferential nucleotide sequences are first determined from a library of recombinant DNA clones having families of repetitive sequences. Library clones are identified with a low homology with a sequence of repetitive DNA families to which the first clones respectively belong and variant sequences are then identified by selecting clones having a pattern of hybridization with genomic DNA dissimilar to the hybridization pattern shown by the respective families. In another embodiment, variant sequences are selected from a sequence of a known repetitive DNA family. The selected variant sequence is classified as chromosome specific, chromosome preferential, or chromosome nonspecific. Sequences which are classified as chromosome preferential are further sequenced and regions are identified having a low homology with other regions of the chromosome preferential sequence or with known sequences of other family me This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).

Is mammalian chromosomal evolution driven by regions of genome fragility?

PubMed Central

Ruiz-Herrera, Aurora; Castresana, Jose; Robinson, Terence J

2006-01-01

Background A fundamental question in comparative genomics concerns the identification of mechanisms that underpin chromosomal change. In an attempt to shed light on the dynamics of mammalian genome evolution, we analyzed the distribution of syntenic blocks, evolutionary breakpoint regions, and evolutionary breakpoints taken from public databases available for seven eutherian species (mouse, rat, cattle, dog, pig, cat, and horse) and the chicken, and examined these for correspondence with human fragile sites and tandem repeats. Results Our results confirm previous investigations that showed the presence of chromosomal regions in the human genome that have been repeatedly used as illustrated by a high breakpoint accumulation in certain chromosomes and chromosomal bands. We show, however, that there is a striking correspondence between fragile site location, the positions of evolutionary breakpoints, and the distribution of tandem repeats throughout the human genome, which similarly reflect a non-uniform pattern of occurrence. Conclusion These observations provide further evidence that certain chromosomal regions in the human genome have been repeatedly used in the evolutionary process. As a consequence, the genome is a composite of fragile regions prone to reorganization that have been conserved in different lineages, and genomic tracts that do not exhibit the same levels of evolutionary plasticity. PMID:17156441

The cld mutation: narrowing the critical chromosomal region and selecting candidate genes.

PubMed

Péterfy, Miklós; Mao, Hui Z; Doolittle, Mark H

2006-10-01

Combined lipase deficiency (cld) is a recessive, lethal mutation specific to the tw73 haplotype on mouse Chromosome 17. While the cld mutation results in lipase proteins that are inactive, aggregated, and retained in the endoplasmic reticulum (ER), it maps separately from the lipase structural genes. We have narrowed the gene critical region by about 50% using the tw18 haplotype for deletion mapping and a recombinant chromosome used originally to map cld with respect to the phenotypic marker tf. The region now extends from 22 to 25.6 Mbp on the wild-type chromosome, currently containing 149 genes and 50 expressed sequence tags (ESTs). To identify the affected gene, we have selected candidates based on their known role in associated biological processes, cellular components, and molecular functions that best fit with the predicted function of the cld gene. A secondary approach was based on differences in mRNA levels between mutant (cld/cld) and unaffected (+/cld) cells. Using both approaches, we have identified seven functional candidates with an ER localization and/or an involvement in protein maturation and folding that could explain the lipase deficiency, and six expression candidates that exhibit large differences in mRNA levels between mutant and unaffected cells. Significantly, two genes were found to be candidates with regard to both function and expression, thus emerging as the strongest candidates for cld. We discuss the implications of our mapping results and our selection of candidates with respect to other genes, deletions, and mutations occurring in the cld critical region.

Anhidrotic ectodermal dysplasia gene region cloned in yeast artificial chromosomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kere, J.; Grzeschik, K.H.; Limon, J.

1993-05-01

Anhidrotic ectodermal dysplasia (EDA), an X-chromosomal recessive disorder, is expressed in a few females with chromosomal translocations involving bands Xq12-q13. Using available DNA markers from the region and somatic cell hybrids the authors mapped the X-chromosomal breakpoints in two such translocations. The breakpoints were further mapped within a yeast artificial chromosome contig constructed by chromosome walking techniques. Genomic DNA markers that map between the two translocation breakpoints were recovered representing putative portions of the EDA gene. 32 refs., 3 figs., 1 tab.

Designing of plant artificial chromosome (PAC) by using the Chlorella smallest chromosome as a model system.

PubMed

Noutoshi, Y; Arai, R; Fujie, M; Yamada, T

1997-01-01

As a model for plant-type chromosomes, we have been characterizing molecular organization of the Chlorella vulgaris C-169 chromosome I. To identify chromosome structural elements including the centromeric region and replication origins, we constructed a chromosome I specific cosmid library and aligned each cosmid clones to generate contigs. So far, more than 80% of the entire chromosome I has been covered. A complete clonal physical reconstitution of chromosome I provides information on the structure and genomic organization of plant genome. We propose our strategy to construct an artificial chromosome by assembling the functional chromosome structural elements identified on Chrorella chromosome I.

[Chromosomal variation in Chironomus plumosus L. (Diptera, Chironomidae) from populations of Bryansk region, Saratov region (Russia), and Gomel region (Belarus)].

PubMed

Belyanina, S I

2015-02-01

Cytogenetic analysis was performed on samples of Chironomus plumosus L. (Diptera, Chironomidae) taken from waterbodies of various types in Bryansk region (Russia) and Gomel region (Belarus). Karyotypes of specimens taken from stream pools of the Volga were used as reference samples. The populations of Bryansk and Gomel regions (except for a population of Lake Strativa in Starodubskii district, Bryansk region) exhibit broad structural variation, including somatic mosaicism for morphotypes of the salivary gland chromosome set, decondensation of telomeric sites, and the presence of small structural changes, as opposed to populations of Saratov region. As compared with Saratov and Bryansk regions, the Balbiani ring in the B-arm of chromosome I is repressed in populations of Gomel region. It is concluded that the chromosome set of Ch. plumosus in a range of waterbodies of Bryansk and Gomel regions is unstable.

[Prevalence of congenital abnormalities identified in fetuses with 13, 18 and 21 chromosomal trisomy].

PubMed

Emer, Caroline Soares Cristofari; Duque, Julio Alejandro Peña; Müller, Ana Lúcia Letti; Gus, Rejane; Sanseverino, Maria Teresa Vieira; da Silva, André Anjos; Magalhães, José Antonio de Azevedo

2015-07-01

To describe the prevalence of malformations found in fetuses with trisomy of chromosomes 13, 18 and 21 by identifying the most frequent within each condition. A retrospective cross-sectional study with the analysis of trisomy cases of chromosomes 13, 18 and 21 diagnosed through fetal karyotype obtained by amniocentesis/cordocentesis, between October 1994 and May 2014, at a Teaching Hospital in Brazil Southern Region. Malformations identified through morphological ultrasonography were described and, subsequently, confirmed in newborn examinations and/or fetal autopsy. The results were analyzed using Fisher's test and analysis of variance (ANOVA), with a 5% level of significance (p=0.05). Sixty-nine cases of trisomy were diagnosed among 840 exams; nine were excluded due to outcome outside Hospital de Clínicas de Porto Alegre or incomplete records, remaining 60 cases (nine cases of chromosome 13 trisomy, 26 of chromosome 18, and 25 of chromosome 21). In all three groups, heart disease occurred in most cases; the ventricular septal defect was more prevalent and occurred in 66.7% of the trisomy 13 group. Gastrointestinal abnormalities were more prevalent in the trisomy 18 group, especially omphalocele (38.5%; p<0.01). Genitourinary anomalies were more significantly frequent in the trisomy 13 group (pyelectasis, 55.6% - p<0.01; ambiguous genitalia, 33.3% - p=0.01). Central nervous system defects were identified in all cases of trisomy 13. Facial cracks were significantly more prevalent among fetuses with trisomy 13 (66.7%; p<0.01). Hand and feet malformations significantly differed among the trisomy groups. Hand defects occurred in 50% of trisomy 18 cases, and in 44.4% of all trisomy 13 cases (p<0.01); congenital clubfoot was more common in the trisomy 18 group, being detected in 46.2% of fetuses (p<0.01). The abnormalities were found in 50.9, 27.3 and 21.7% of trisomy 18, 13 and 21 cases respectively. Many fetal malformations identified at ultrasound are suggestive of

Process of labeling specific chromosomes using recombinant repetitive DNA

DOEpatents

Moyzis, R.K.; Meyne, J.

1988-02-12

Chromosome preferential nucleotide sequences are first determined from a library of recombinant DNA clones having families of repetitive sequences. Library clones are identified with a low homology with a sequence of repetitive DNA families to which the first clones respectively belong and variant sequences are then identified by selecting clones having a pattern of hybridization with genomic DNA dissimilar to the hybridization pattern shown by the respective families. In another embodiment, variant sequences are selected from a sequence of a known repetitive DNA family. The selected variant sequence is classified as chromosome specific, chromosome preferential, or chromosome nonspecific. Sequences which are classified as chromosome preferential are further sequenced and regions are identified having a low homology with other regions of the chromosome preferential sequence or with known sequences of other family members and consensus sequences of the repetitive DNA families for the chromosome preferential sequences. The selected low homology regions are then hybridized with chromosomes to determine those low homology regions hybridized with a specific chromosome under normal stringency conditions.

The database of chromosome imbalance regions and genes resided in lung cancer from Asian and Caucasian identified by array-comparative genomic hybridization

PubMed Central

2012-01-01

Background Cancer-related genes show racial differences. Therefore, identification and characterization of DNA copy number alteration regions in different racial groups helps to dissect the mechanism of tumorigenesis. Methods Array-comparative genomic hybridization (array-CGH) was analyzed for DNA copy number profile in 40 Asian and 20 Caucasian lung cancer patients. Three methods including MetaCore analysis for disease and pathway correlations, concordance analysis between array-CGH database and the expression array database, and literature search for copy number variation genes were performed to select novel lung cancer candidate genes. Four candidate oncogenes were validated for DNA copy number and mRNA and protein expression by quantitative polymerase chain reaction (qPCR), chromogenic in situ hybridization (CISH), reverse transcriptase-qPCR (RT-qPCR), and immunohistochemistry (IHC) in more patients. Results We identified 20 chromosomal imbalance regions harboring 459 genes for Caucasian and 17 regions containing 476 genes for Asian lung cancer patients. Seven common chromosomal imbalance regions harboring 117 genes, included gain on 3p13-14, 6p22.1, 9q21.13, 13q14.1, and 17p13.3; and loss on 3p22.2-22.3 and 13q13.3 were found both in Asian and Caucasian patients. Gene validation for four genes including ARHGAP19 (10q24.1) functioning in Rho activity control, FRAT2 (10q24.1) involved in Wnt signaling, PAFAH1B1 (17p13.3) functioning in motility control, and ZNF322A (6p22.1) involved in MAPK signaling was performed using qPCR and RT-qPCR. Mean gene dosage and mRNA expression level of the four candidate genes in tumor tissues were significantly higher than the corresponding normal tissues (P<0.001~P=0.06). In addition, CISH analysis of patients indicated that copy number amplification indeed occurred for ARHGAP19 and ZNF322A genes in lung cancer patients. IHC analysis of paraffin blocks from Asian Caucasian patients demonstrated that the frequency of PAFAH1B1

Fine Mapping and Evolution of a QTL Region on Cattle Chromosome 3

ERIC Educational Resources Information Center

Donthu, Ravikiran

2009-01-01

The goal of my dissertation was to fine map the milk yield and composition quantitative trait loci (QTL) mapped to cattle chromosome 3 (BTA3) by Heyen et al. (1999) and to identify candidate genes affecting these traits. To accomplish this, the region between "BL41" and "TGLA263" was mapped to the cattle genome sequence assembly Btau 3.1 and a…

Regional gene mapping using mixed radiation hybrids and reverse chromosome painting.

PubMed

Lin, J Y; Bedford, J S

1997-11-01

We describe a new approach for low-resolution physical mapping using pooled DNA probe from mixed (non-clonal) populations of human-CHO cell hybrids and reverse chromosome painting. This mapping method is based on a process in which the human chromosome fragments bearing a complementing gene were selectively retained in a large non-clonal population of CHO-human hybrid cells during a series of 12- to 15-Gy gamma irradiations each followed by continuous growth selection. The location of the gene could then be identified by reverse chromosome painting on normal human metaphase spreads using biotinylated DNA from this population of "enriched" hybrid cells. We tested the validity of this method by correctly mapping the complementing human HPRT gene, whose location is well established. We then demonstrated the method's usefulness by mapping the chromosome location of a human gene which complemented the defect responsible for the hypersensitivity to ionizing radiation in CHO irs-20 cells. This method represents an efficient alternative to conventional concordance analysis in somatic cell hybrids where detailed chromosome analysis of numerous hybrid clones is necessary. Using this approach, it is possible to localize a gene for which there is no prior sequence or linkage information to a subchromosomal region, thus facilitating association with known mapping landmarks (e.g. RFLP, YAC or STS contigs) for higher-resolution mapping.

Exclusion of primary congenital glaucoma (buphthalmos) from two candidate regions of chromosome arm 6p and chromosome 11

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akarsu, A.N.; Hossain, A.; Sarfarazi, M.

1996-01-22

Primary congenital glaucoma (gene symbol: GLC3) is characterized by an improper development of the aqueous outflow system. The reduced outflow of fluid results in an increased intraocular pressure leading to buphthalmos, optic nerve damage, and eventual visual impairment. GLC3 is a heterogeneous condition with an estimated incidence of 1:2,500 in Middle Eastern and 1:10,000 in Western countries. In many families, GLC3 is an autosomal recessive trait with presentation of an earlier age-of-onset, high intraocular pressure, enlarged cloudy cornea, buphthalmos, and a more aggressive course. The pathogenesis of GLC3 remains elusive despite extensive histologic efforts to identify a single anatomic defect.more » Recent advances in positional mapping and cloning of human disorders provided an opportunity to identify chromosome locations of the GLC3 phenotype. Our laboratory is currently involved in the mapping of this condition by using a combination of candidate chromosome regions associated with the GLC3 phenotype and by a general positional mapping strategy. 16 refs., 3 tabs.« less

Applying deep learning technology to automatically identify metaphase chromosomes using scanning microscopic images: an initial investigation

NASA Astrophysics Data System (ADS)

Qiu, Yuchen; Lu, Xianglan; Yan, Shiju; Tan, Maxine; Cheng, Samuel; Li, Shibo; Liu, Hong; Zheng, Bin

2016-03-01

Automated high throughput scanning microscopy is a fast developing screening technology used in cytogenetic laboratories for the diagnosis of leukemia or other genetic diseases. However, one of the major challenges of using this new technology is how to efficiently detect the analyzable metaphase chromosomes during the scanning process. The purpose of this investigation is to develop a computer aided detection (CAD) scheme based on deep learning technology, which can identify the metaphase chromosomes with high accuracy. The CAD scheme includes an eight layer neural network. The first six layers compose of an automatic feature extraction module, which has an architecture of three convolution-max-pooling layer pairs. The 1st, 2nd and 3rd pair contains 30, 20, 20 feature maps, respectively. The seventh and eighth layers compose of a multiple layer perception (MLP) based classifier, which is used to identify the analyzable metaphase chromosomes. The performance of new CAD scheme was assessed by receiver operation characteristic (ROC) method. A number of 150 regions of interest (ROIs) were selected to test the performance of our new CAD scheme. Each ROI contains either interphase cell or metaphase chromosomes. The results indicate that new scheme is able to achieve an area under the ROC curve (AUC) of 0.886+/-0.043. This investigation demonstrates that applying a deep learning technique may enable to significantly improve the accuracy of the metaphase chromosome detection using a scanning microscopic imaging technology in the future.

Small Supernumerary Marker Chromosome May Provide Information on Dosage-insensitive Pericentric Regions in Human.

PubMed

Al-Rikabi, Ahmed B Hamid; Pekova, Sona; Fan, Xioabo; Jančušková, Tereza; Liehr, Thomas

2018-04-01

Cytogenetically visible chromosomal imbalances in humans are deleterious and adverse in the majority of the cases. However, healthy persons living with chromosomal imbalances in the range of several megabasepairs (Mbps) in size, like carriers of small Supernumerary Marker Chromosomes (sSMCs) exist. The identification of healthy sSMC carriers with euchromatic centromere-near (ECN) imbalances led to the following proposal: ECN-regions do not contain any dosage sensitive genes. Due to own previous work, dosage-insensitive pericentric ECN-regions were already determined with an accuracy of 0.3 and 5 Mbp. Based on this data we established 43 new pericentromeric probe sets spanning about 3-5 Mbp of each euchromatic human chromosome arm starting from the known insensitive regions towards distal. Such so called pericentromeric-critical region fluorescence in situ hybridization (PeCR-FISH) probe sets were applied exemplarily and successful here in 15 sSMC cases as available from the Else Kröner-Fresenius-sSMC-cellbank . Most of the involved sSMC breakpoints could be characterized as a higher resolution than before. An unexpected result was that in 5/15 cases cryptic mosaicism was characterized. The latter is also to be considered to have potentially an influence on the clinical outcome in these so-called discontinuous sSMCs. Overall, the suitability of PeCR-FISH to characterize sSMCs was proven; the potential of this probe set to further delineate sizes of dosage insensitive pericentric regions is obvious but dependent on suited cases. Furthermore, discontinuous sSMCs can be identified by this approach and this new subtype of sSMC needs to be studied in more detail in future.

Genomic structure and paralogous regions of the inversion breakpoint occurring between human chromosome 3p12.3 and orangutan chromosome 2.

PubMed

Yue, Y; Grossmann, B; Tsend-Ayush, E; Grützner, F; Ferguson-Smith, M A; Yang, F; Haaf, T

2005-01-01

Intrachromosomal duplications play a significant role in human genome pathology and evolution. To better understand the molecular basis of evolutionary chromosome rearrangements, we performed molecular cytogenetic and sequence analyses of the breakpoint region that distinguishes human chromosome 3p12.3 and orangutan chromosome 2. FISH with region-specific BAC clones demonstrated that the breakpoint-flanking sequences are duplicated intrachromosomally on orangutan 2 and human 3q21 as well as at many pericentromeric and subtelomeric sites throughout the genomes. Breakage and rearrangement of the human 3p12.3-homologous region in the orangutan lineage were associated with a partial loss of duplicated sequences in the breakpoint region. Consistent with our FISH mapping results, computational analysis of the human chromosome 3 genomic sequence revealed three 3p12.3-paralogous sequence blocks on human chromosome 3q21 and smaller blocks on the short arm end 3p26-->p25. This is consistent with the view that sequences from an ancestral site at 3q21 were duplicated at 3p12.3 in a common ancestor of orangutan and humans. Our results show that evolutionary chromosome rearrangements are associated with microduplications and microdeletions, contributing to the DNA differences between closely related species. Copyright (c) 2005 S. Karger AG, Basel.

Rescue of Targeted Regions of Mammalian Chromosomes by in Vivo Recombination in Yeast

PubMed Central

Kouprina, Natalya; Kawamoto, Kensaku; Barrett, J. Carl; Larionov, Vladimir; Koi, Minoru

1998-01-01

In contrast to other animal cell lines, the chicken pre-B cell lymphoma line, DT40, exhibits a high level of homologous recombination, which can be exploited to generate site-specific alterations in defined target genes or regions. In addition, the ability to generate human/chicken monochromosomal hybrids in the DT40 cell line opens a way for specific targeting of human genes. Here we describe a new strategy for direct isolation of a human chromosomal region that is based on targeting of the chromosome with a vector containing a yeast selectable marker, centromere, and an ARS element. This procedure allows rescue of the targeted region by transfection of total genomic DNA into yeast spheroplasts. Selection for the yeast marker results in isolation of chromosome sequences in the form of large circular yeast artificial chromosomes (YACs) up to 170 kb in size containing the targeted region. These YACs are generated by homologous recombination in yeast between common repeated sequences in the targeted chromosomal fragment. Alternatively, the targeted region can be rescued as a linear YACs when a YAC fragmentation vector is included in the yeast transformation mixture. Because the entire isolation procedure of the chromosomal region, once a target insertion is obtained, can be accomplished in ∼1 week, the new method greatly expands the utility of the homologous recombinationproficient DT40 chicken cell system. PMID:9647640

Segmental duplications and evolutionary plasticity at tumor chromosome break-prone regions

PubMed Central

Darai-Ramqvist, Eva; Sandlund, Agneta; Müller, Stefan; Klein, George; Imreh, Stefan; Kost-Alimova, Maria

2008-01-01

We have previously found that the borders of evolutionarily conserved chromosomal regions often coincide with tumor-associated deletion breakpoints within human 3p12-p22. Moreover, a detailed analysis of a frequently deleted region at 3p21.3 (CER1) showed associations between tumor breaks and gene duplications. We now report on the analysis of 54 chromosome 3 breaks by multipoint FISH (mpFISH) in 10 carcinoma-derived cell lines. The centromeric region was broken in five lines. In lines with highly complex karyotypes, breaks were clustered near known fragile sites, FRA3B, FRA3C, and FRA3D (three lines), and in two other regions: 3p12.3-p13 (∼75 Mb position) and 3q21.3-q22.1 (∼130 Mb position) (six lines). All locations are shown based on NCBI Build 36.1 human genome sequence. The last two regions participated in three of four chromosome 3 inversions during primate evolution. Regions at 75, 127, and 131 Mb positions carry a large (∼250 kb) segmental duplication (tumor break-prone segmental duplication [TBSD]). TBSD homologous sequences were found at 15 sites on different chromosomes. They were located within bands frequently involved in carcinoma-associated breaks. Thirteen of them have been involved in inversions during primate evolution; 10 were reused by breaks during mammalian evolution; 14 showed copy number polymorphism in man. TBSD sites showed an increase in satellite repeats, retrotransposed sequences, and other segmental duplications. We propose that the instability of these sites stems from specific organization of the chromosomal region, associated with location at a boundary between different CG-content isochores and with the presence of TBSDs and “instability elements,” including satellite repeats and retroviral sequences. PMID:18230801

Segmental duplications and evolutionary plasticity at tumor chromosome break-prone regions.

PubMed

Darai-Ramqvist, Eva; Sandlund, Agneta; Müller, Stefan; Klein, George; Imreh, Stefan; Kost-Alimova, Maria

2008-03-01

We have previously found that the borders of evolutionarily conserved chromosomal regions often coincide with tumor-associated deletion breakpoints within human 3p12-p22. Moreover, a detailed analysis of a frequently deleted region at 3p21.3 (CER1) showed associations between tumor breaks and gene duplications. We now report on the analysis of 54 chromosome 3 breaks by multipoint FISH (mpFISH) in 10 carcinoma-derived cell lines. The centromeric region was broken in five lines. In lines with highly complex karyotypes, breaks were clustered near known fragile sites, FRA3B, FRA3C, and FRA3D (three lines), and in two other regions: 3p12.3-p13 ( approximately 75 Mb position) and 3q21.3-q22.1 ( approximately 130 Mb position) (six lines). All locations are shown based on NCBI Build 36.1 human genome sequence. The last two regions participated in three of four chromosome 3 inversions during primate evolution. Regions at 75, 127, and 131 Mb positions carry a large ( approximately 250 kb) segmental duplication (tumor break-prone segmental duplication [TBSD]). TBSD homologous sequences were found at 15 sites on different chromosomes. They were located within bands frequently involved in carcinoma-associated breaks. Thirteen of them have been involved in inversions during primate evolution; 10 were reused by breaks during mammalian evolution; 14 showed copy number polymorphism in man. TBSD sites showed an increase in satellite repeats, retrotransposed sequences, and other segmental duplications. We propose that the instability of these sites stems from specific organization of the chromosomal region, associated with location at a boundary between different CG-content isochores and with the presence of TBSDs and "instability elements," including satellite repeats and retroviral sequences.

Characterization of chromosomal regions conserved in Yersinia pseudotuberculosis and lost by Yersinia pestis.

PubMed

Pouillot, Flavie; Fayolle, Corinne; Carniel, Elisabeth

2008-10-01

The transformation of the enteropathogenic bacterium Yersinia pseudotuberculosis into the plague bacillus, Yersinia pestis, has been accompanied by extensive genetic loss. This study focused on chromosomal regions conserved in Y. pseudotuberculosis and lost during its transformation into Y. pestis. An extensive PCR screening of 78 strains of the two species identified five regions (R1 to R5) and four open reading frames (ORFs; orf1 to orf4) that were conserved in Y. pseudotuberculosis and absent from Y. pestis. Their conservation in Y. pseudotuberculosis suggests a positive selective pressure and a role during the life cycle of this species. Attempts to delete two ORFs (orf3 and orf4) from the chromosome of strain IP32953 were unsuccessful, indicating that they are essential for its viability. The seven remaining loci were individually deleted from the IP32953 chromosome, and the ability of each mutant to grow in vitro and to kill mice upon intragastric infection was evaluated. Four loci (orf1, R2, R4, and R5) were not required for optimal growth or virulence of Y. pseudotuberculosis. In contrast, orf2, encoding a putative pseudouridylate synthase involved in RNA stability, was necessary for the optimal growth of IP32953 at 37 degrees C in a chemically defined medium (M63S). Deletion of R1, a region predicted to encode the methionine salvage pathway, altered the mutant pathogenicity, suggesting that the availability of free methionine is severely restricted in vivo. R3, a region composed mostly of genes of unknown functions, was necessary for both optimal growth of Y. pseudotuberculosis at 37 degrees C in M63S and for virulence. Therefore, despite their loss in Y. pestis, five of the nine Y. pseudotuberculosis-specific chromosomal loci studied play a role in the survival, growth, or virulence of this species.

Gene order and recombination rate in homologous chromosome regions of the chicken and a passerine bird.

PubMed

Dawson, Deborah A; Akesson, Mikael; Burke, Terry; Pemberton, Josephine M; Slate, Jon; Hansson, Bengt

2007-07-01

Genome structure has been found to be highly conserved between distantly related birds and recent data for a limited part of the genome suggest that this is true also for the gene order (synteny) within chromosomes. Here, we confirm that synteny is maintained for large chromosomal regions in chicken and a passerine bird, the great reed warbler Acrocephalus arundinaceus, with few rearrangements, but in contrast show that the recombination-based linkage map distances differ substantially between these species. We assigned a chromosomal location based on sequence similarity to the chicken genome sequence to a set of microsatellite loci mapped in a pedigree of great reed warblers. We detected homologous loci on 14 different chromosomes corresponding to chicken chromosomes Gga1-5, 7-9, 13, 19, 20, 24, 25, and Z. It is known that 2 passerine macrochromosomes correspond to the chicken chromosome Gga1. Homology of 2 different great reed warbler linkage groups (LG13 and LG5) to Gga1 allowed us to locate the split to a position between 20.8 and 84.8 Mb on Gga1. Data from the 5 chromosomal regions (on Gga1, 2, 3, 5, and Z) with 3 or more homologous loci showed that synteny was conserved with the exception of 2 large previously unreported inversions on Gga1/LG5 and Gga2/LG3, respectively. Recombination data from the 9 chromosomal regions in which we identified 2 or more homologous loci (accounting for the inversions) showed that the linkage map distances in great reed warblers were only 6.3% and 13.3% of those in chickens for males and females, respectively. This is likely to reflect the true interspecific difference in recombination rate because our markers were not located in potentially low-recombining regions: several linkage groups covered a substantial part of their corresponding chicken chromosomes and were not restricted to centromeres. We conclude that recombination rates may differ strongly between bird species with highly conserved genome structure and synteny and

Linkage Disequilibrium Mapping in Domestic Dog Breeds Narrows the Progressive Rod-Cone Degeneration (prcd) Interval and Identifies Ancestral Disease Transmitting Chromosome

PubMed Central

Goldstein, Orly; Zangerl, Barbara; Pearce-Kelling, Sue; Sidjanin, Duska J.; Kijas, James W.; Felix, Jeanette; Acland, Gregory M; Aguirre, Gustavo D.

2014-01-01

Canine progressive rod-cone degeneration (prcd) is a retinal disease previously mapped to a broad, gene-rich centromeric region of canine chromosome 9. As allelic disorders are present in multiple breeds, we used linkage disequilibrium (LD) to narrow the ∼6.4 Mb interval candidate region. Multiple dog breeds, each representing genetically isolated populations, were typed for SNPs and other polymorphisms identified from BACs. The candidate region was initially localized to a 1.5 Mb zero recombination interval between growth factor receptor-bound protein 2 (GRB2) and SEC14-like 1 (SEC14L). A fine-scale haplotype of the region was developed which reduced the LD interval to 106 Kb, and identified a conserved haplotype of 98 polymorphisms present in all prcd-affected chromosomes from 14 different dog breeds. The findings strongly suggest that a common ancestor transmitted the prcd disease allele to many of the modern dog breeds, and demonstrate the power of LD approach in the canine model. PMID:16859891

Identifying sites of replication initiation in yeast chromosomes: looking for origins in all the right places.

PubMed

van Brabant, A J; Hunt, S Y; Fangman, W L; Brewer, B J

1998-06-01

DNA fragments that contain an active origin of replication generate bubble-shaped replication intermediates with diverging forks. We describe two methods that use two-dimensional (2-D) agarose gel electrophoresis along with DNA sequence information to identify replication origins in natural and artificial Saccharomyces cerevisiae chromosomes. The first method uses 2-D gels of overlapping DNA fragments to locate an active chromosomal replication origin within a region known to confer autonomous replication on a plasmid. A variant form of 2-D gels can be used to determine the direction of fork movement, and the second method uses this technique to find restriction fragments that are replicated by diverging forks, indicating that a bidirectional replication origin is located between the two fragments. Either of these two methods can be applied to the analysis of any genomic region for which there is DNA sequence information or an adequate restriction map.

Comparative physical mapping between wheat chromosome arm 2BL and rice chromosome 4.

PubMed

Lee, Tong Geon; Lee, Yong Jin; Kim, Dae Yeon; Seo, Yong Weon

2010-12-01

Physical maps of chromosomes provide a framework for organizing and integrating diverse genetic information. DNA microarrays are a valuable technique for physical mapping and can also be used to facilitate the discovery of single feature polymorphisms (SFPs). Wheat chromosome arm 2BL was physically mapped using a Wheat Genome Array onto near-isogenic lines (NILs) with the aid of wheat-rice synteny and mapped wheat EST information. Using high variance probe set (HVP) analysis, 314 HVPs constituting genes present on 2BL were identified. The 314 HVPs were grouped into 3 categories: HVPs that match only rice chromosome 4 (298 HVPs), those that match only wheat ESTs mapped on 2BL (1), and those that match both rice chromosome 4 and wheat ESTs mapped on 2BL (15). All HVPs were converted into gene sets, which represented either unique rice gene models or mapped wheat ESTs that matched identified HVPs. Comparative physical maps were constructed for 16 wheat gene sets and 271 rice gene sets. Of the 271 rice gene sets, 257 were mapped to the 18-35 Mb regions on rice chromosome 4. Based on HVP analysis and sequence similarity between the gene models in the rice chromosomes and mapped wheat ESTs, the outermost rice gene model that limits the translocation breakpoint to orthologous regions was identified.

Exclusion of primary congenital glaucoma (PCG) from two candidate regions of chromosomes 1 and 6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarfarazi, M.; Akarsu, A.N.; Barsoum-Homsy, M.

1994-09-01

PCG is a genetically heterogeneous condition in which a significant proportion of families inherit in an autosomally recessive fashion. Although association of PCG with chromosomal abnormalities has been repeatedly reported in the literature, the chromosomal location of this condition is still unknown. Therefore, this study is designed to identify the chromosomal location of the PCG locus by positional mapping. We have identified 80 PCG families with a total of 261 potential informative meiosis. A group of 19 pedigrees with a minimum of 2 affected children in each pedigree and consanguinity in most of the parental generation were selected as ourmore » initial screening panel. This panel consists of a total of 44 affected and 93 unaffected individuals giving a total of 99 informative meiosis, including 5 phase-known. We used polymerase chain reaction (PCR), denaturing polyacrylamide gels and silver staining to genotype our families. We first screened for markers on 1q21-q31, the reported location for juvenile primary open-angle glaucoma and excluded a region of 30 cM as the likely site for the PCG locus. Association of PCG with both ring chromosome 6 and HLA-B8 has also been reported. Therefore, we genotyped our PCG panel with PCR applicable markers from 6p21. Significant negative lod scores were obtained for D6S105 (Z = -18.70) and D6S306 (Z = -5.99) at {theta}=0.001. HLA class 1 region has also contained one of the tubulin genes (TUBB) which is an obvious candidate for PCG. Study of this gene revealed a significant negative lod score with PCG (Z = -16.74, {theta}=0.001). A multipoint linkage analysis of markers in this and other regions containing the candidate genes will be presented.« less

A high-density SNP linkage scan with 142 combined subtype ADHD sib pairs identifies linkage regions on chromosomes 9 and 16.

PubMed

Asherson, P; Zhou, K; Anney, R J L; Franke, B; Buitelaar, J; Ebstein, R; Gill, M; Altink, M; Arnold, R; Boer, F; Brookes, K; Buschgens, C; Butler, L; Cambell, D; Chen, W; Christiansen, H; Feldman, L; Fleischman, K; Fliers, E; Howe-Forbes, R; Goldfarb, A; Heise, A; Gabriëls, I; Johansson, L; Lubetzki, I; Marco, R; Medad, S; Minderaa, R; Mulas, F; Müller, U; Mulligan, A; Neale, B; Rijsdijk, F; Rabin, K; Rommelse, N; Sethna, V; Sorohan, J; Uebel, H; Psychogiou, L; Weeks, A; Barrett, R; Xu, X; Banaschewski, T; Sonuga-Barke, E; Eisenberg, J; Manor, I; Miranda, A; Oades, R D; Roeyers, H; Rothenberger, A; Sergeant, J; Steinhausen, H-C; Taylor, E; Thompson, M; Faraone, S V

2008-05-01

As part of the International Multi-centre ADHD Genetics project we completed an affected sibling pair study of 142 narrowly defined Diagnostic and Statistical Manual of Mental Disorders, fourth edition combined type attention deficit hyperactivity disorder (ADHD) proband-sibling pairs. No linkage was observed on the most established ADHD-linked genomic regions of 5p and 17p. We found suggestive linkage signals on chromosomes 9 and 16, respectively, with the highest multipoint nonparametric linkage signal on chromosome 16q23 at 99 cM (log of the odds, LOD=3.1) overlapping data published from the previous UCLA (University of California, Los Angeles) (LOD>1, approximately 95 cM) and Dutch (LOD>1, approximately 100 cM) studies. The second highest peak in this study was on chromosome 9q22 at 90 cM (LOD=2.13); both the previous UCLA and German studies also found some evidence of linkage at almost the same location (UCLA LOD=1.45 at 93 cM; German LOD=0.68 at 100 cM). The overlap of these two main peaks with previous findings suggests that loci linked to ADHD may lie within these regions. Meta-analysis or reanalysis of the raw data of all the available ADHD linkage scan data may help to clarify whether these represent true linked loci.

Genetic and physical map of the von Recklinghausen neurofibromatosis (NF1) region on chromosome 17

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yagle, M.K.; Parruti, G.; Xu, W.

The von Recklinghausen neurofibromatosis 1 (NF1) locus has been previously assigned to the proximal long arm of chromosome 17, and two NF1 patients have been identified who have constitutional balanced translocations involving 17q11.2. The authors have constructed a cosmid library from a chromosome-mediated gene transfectant, KLT8, that contains approximately 10% of chromosome 17, including 17q11.2. Cosmids isolated from this library have been mapped across a panel of somatic cell hybrids, including the hybrids from the two patients, and have been localized to seven small regions of proximal 17q. They have 5 cosmids that map directly above the two NF1 translocations,more » and 11 cosmids that map directly below. Of these, 2 cosmids in each region are linked to the disease locus and 3 of these cosmids show no recombination. One distal cosmid, 2B/B35, detects the two NF1 translocations by pulsed-field gel analysis and has been used to produce a long-range restriction map that covers the translocations.« less

Interspecies synteny mapping identifies a quantitative trait locus for bone mineral density on human chromosome Xp22.

PubMed

Parsons, Claire A; Mroczkowski, H Joel; McGuigan, Fiona E A; Albagha, Omar M E; Manolagas, Stavros; Reid, David M; Ralston, Stuart H; Shmookler Reis, Robert J

2005-11-01

Bone mineral density (BMD) is a complex trait with a strong genetic component and an important predictor of osteoporotic fracture risk. Here we report the use of a cross-species strategy to identify genes that regulate BMD, proceeding from quantitative trait mapping in mice to association mapping of the syntenic region in the human genome. We identified a quantitative trait locus (QTL) on the mouse X-chromosome for post-maturity change in spine BMD in a cross of SAMP6 and AKR/J mice and conducted association mapping of the syntenic region on human chromosome Xp22. We studied 76 single nucleotide polymorphisms (SNP) from the human region in two sets of DNA pools prepared from individuals with lumbar spine-BMD (LS-BMD) values falling into the top and bottom 13th percentiles of a population-based study of 3100 post-menopausal women. This procedure identified a region of significant association for two adjacent SNP (rs234494 and rs234495) within the Xp22 locus (P<0.001). Individual genotyping for rs234494 in the BMD pools confirmed the presence of an association for alleles (P=0.018) and genotypes (P=0.008). Analysis of rs234494 and rs234495 in 1053 women derived from the same population who were not selected for BMD values showed an association with LS-BMD for rs234495 (P=0.01) and for haplotypes defined by both SNP (P=0.002). Our study illustrates that interspecies synteny can be used to identify and refine QTL for complex traits and represents the first example where a human QTL for BMD regulation has been mapped using this approach.

Pooled-DNA sequencing identifies genomic regions of selection in Nigerian isolates of Plasmodium falciparum.

PubMed

Oyebola, Kolapo M; Idowu, Emmanuel T; Olukosi, Yetunde A; Awolola, Taiwo S; Amambua-Ngwa, Alfred

2017-06-29

The burden of falciparum malaria is especially high in sub-Saharan Africa. Differences in pressure from host immunity and antimalarial drugs lead to adaptive changes responsible for high level of genetic variations within and between the parasite populations. Population-specific genetic studies to survey for genes under positive or balancing selection resulting from drug pressure or host immunity will allow for refinement of interventions. We performed a pooled sequencing (pool-seq) of the genomes of 100 Plasmodium falciparum isolates from Nigeria. We explored allele-frequency based neutrality test (Tajima's D) and integrated haplotype score (iHS) to identify genes under selection. Fourteen shared iHS regions that had at least 2 SNPs with a score > 2.5 were identified. These regions code for genes that were likely to have been under strong directional selection. Two of these genes were the chloroquine resistance transporter (CRT) on chromosome 7 and the multidrug resistance 1 (MDR1) on chromosome 5. There was a weak signature of selection in the dihydrofolate reductase (DHFR) gene on chromosome 4 and MDR5 genes on chromosome 13, with only 2 and 3 SNPs respectively identified within the iHS window. We observed strong selection pressure attributable to continued chloroquine and sulfadoxine-pyrimethamine use despite their official proscription for the treatment of uncomplicated malaria. There was also a major selective sweep on chromosome 6 which had 32 SNPs within the shared iHS region. Tajima's D of circumsporozoite protein (CSP), erythrocyte-binding antigen (EBA-175), merozoite surface proteins - MSP3 and MSP7, merozoite surface protein duffy binding-like (MSPDBL2) and serine repeat antigen (SERA-5) were 1.38, 1.29, 0.73, 0.84 and 0.21, respectively. We have demonstrated the use of pool-seq to understand genomic patterns of selection and variability in P. falciparum from Nigeria, which bears the highest burden of infections. This investigation identified known

Small supernumerary marker chromosome derived from proximal p-arm of chromosome 2: identification by fluorescent in situ hybridization.

PubMed

Lasan Trcić, Ruzica; Hitrec, Vlasta; Letica, Ljiljana; Cuk, Mario; Begović, Davor

2003-08-01

Conventional cytogenetics detected an interstitial deletion of proximal region of p-arm of chromosome 2 in a 6-month-old boy with a phenotype slightly resembling Down's syndrome. The deletion was inherited from the father, whose karyotype revealed a small ring-shaped marker chromosome, in addition to interstitial deletion. Fluorescence in situ hybridization identified the marker, which consisted of the proximal region of the p-arm of chromosome 2, including a part of its centromere. This case shows that molecular cytogenetic analysis can reveal the mechanism of the formation of the marker chromosome.

Double insertion of homogeneously staining regions in chromosome 1 of wild Mus musculus musculus: effects on chromosome pairing and recombination.

PubMed

Borodin, P M; Gorlov, I P; Ladygina TYu

1990-01-01

An examination of the meiotic pattern of chromosome 1 isolated from a feral mouse population and containing a double insertion (Is) of homogeneously staining regions (HSRs) was carried out. The region delineated by the proximal breakpoint of Is(HSR;1C5) 1Icg and the distal breakpoint of Is(HSR;1E3)2Icg is desynapsed during the early pachytene stage and heterosynapsed at the midpachytene, as shown by electron microscopic analysis of synaptonemal complexes. The HSRs have no effect on the segregation of chromosome 1 in heterozygous mice. The lack of homosynapsis in the region under study causes chiasmata redistribution in heteromorphic bivalents. In normal males, single chiasmata are located in the medial part of the chromosome. In heterozygotes, this segment is heterosynapsed and unavailable for recombination. This leads to a significant decrease in the frequency of bivalents bearing single chiasmata. The total number of chiasmata per bivalent is much higher in heterozygous males than in normal ones. The recombination frequency between proximal markers fz and In also is higher in heterozygous animals. The increase in the total chiasma number in the heteromorphic bivalent is due to the addition of double chiasmata located mostly at precentromeric and pretelomeric regions of the chromosome.

Centromere Destiny in Dicentric Chromosomes: New Insights from the Evolution of Human Chromosome 2 Ancestral Centromeric Region.

PubMed

Chiatante, Giorgia; Giannuzzi, Giuliana; Calabrese, Francesco Maria; Eichler, Evan E; Ventura, Mario

2017-07-01

Dicentric chromosomes are products of genomic rearrangements that place two centromeres on the same chromosome. Due to the presence of two primary constrictions, they are inherently unstable and overcome their instability by epigenetically inactivating and/or deleting one of the two centromeres, thus resulting in functionally monocentric chromosomes that segregate normally during cell division. Our understanding to date of dicentric chromosome formation, behavior and fate has been largely inferred from observational studies in plants and humans as well as artificially produced de novo dicentrics in yeast and in human cells. We investigate the most recent product of a chromosome fusion event fixed in the human lineage, human chromosome 2, whose stability was acquired by the suppression of one centromere, resulting in a unique difference in chromosome number between humans (46 chromosomes) and our most closely related ape relatives (48 chromosomes). Using molecular cytogenetics, sequencing, and comparative sequence data, we deeply characterize the relicts of the chromosome 2q ancestral centromere and its flanking regions, gaining insight into the ancestral organization that can be easily broadened to all acrocentric chromosome centromeres. Moreover, our analyses offered the opportunity to trace the evolutionary history of rDNA and satellite III sequences among great apes, thus suggesting a new hypothesis for the preferential inactivation of some human centromeres, including IIq. Our results suggest two possible centromere inactivation models to explain the evolutionarily stabilization of human chromosome 2 over the last 5-6 million years. Our results strongly favor centromere excision through a one-step process. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Genotype–phenotype correlations in Down syndrome identified by array CGH in 30 cases of partial trisomy and partial monosomy chromosome 21

PubMed Central

Lyle, Robert; Béna, Frédérique; Gagos, Sarantis; Gehrig, Corinne; Lopez, Gipsy; Schinzel, Albert; Lespinasse, James; Bottani, Armand; Dahoun, Sophie; Taine, Laurence; Doco-Fenzy, Martine; Cornillet-Lefèbvre, Pascale; Pelet, Anna; Lyonnet, Stanislas; Toutain, Annick; Colleaux, Laurence; Horst, Jürgen; Kennerknecht, Ingo; Wakamatsu, Nobuaki; Descartes, Maria; Franklin, Judy C; Florentin-Arar, Lina; Kitsiou, Sophia; Aït Yahya-Graison, Emilie; Costantine, Maher; Sinet, Pierre-Marie; Delabar, Jean M; Antonarakis, Stylianos E

2009-01-01

Down syndrome (DS) is one of the most frequent congenital birth defects, and the most common genetic cause of mental retardation. In most cases, DS results from the presence of an extra copy of chromosome 21. DS has a complex phenotype, and a major goal of DS research is to identify genotype–phenotype correlations. Cases of partial trisomy 21 and other HSA21 rearrangements associated with DS features could identify genomic regions associated with specific phenotypes. We have developed a BAC array spanning HSA21q and used array comparative genome hybridization (aCGH) to enable high-resolution mapping of pathogenic partial aneuploidies and unbalanced translocations involving HSA21. We report the identification and mapping of 30 pathogenic chromosomal aberrations of HSA21 consisting of 19 partial trisomies and 11 partial monosomies for different segments of HSA21. The breakpoints have been mapped to within ∼85 kb. The majority of the breakpoints (26 of 30) for the partial aneuploidies map within a 10-Mb region. Our data argue against a single DS critical region. We identify susceptibility regions for 25 phenotypes for DS and 27 regions for monosomy 21. However, most of these regions are still broad, and more cases are needed to narrow down the phenotypic maps to a reasonable number of candidate genomic elements per phenotype. PMID:19002211

Comparative mapping of DNA markers from the familial Alzheimer disease and Down syndrome regions of human chromosome 21 to mouse chromosomes 16 and 17.

PubMed

Cheng, S V; Nadeau, J H; Tanzi, R E; Watkins, P C; Jagadesh, J; Taylor, B A; Haines, J L; Sacchi, N; Gusella, J F

1988-08-01

Mouse trisomy 16 has been proposed as an animal model of Down syndrome (DS), since this chromosome contains homologues of several loci from the q22 band of human chromosome 21. The recent mapping of the defect causing familial Alzheimer disease (FAD) and the locus encoding the Alzheimer amyloid beta precursor protein (APP) to human chromosome 21 has prompted a more detailed examination of the extent of conservation of this linkage group between the two species. Using anonymous DNA probes and cloned genes from human chromosome 21 in a combination of recombinant inbred and interspecific mouse backcross analyses, we have established that the linkage group shared by mouse chromosome 16 includes not only the critical DS region of human chromosome 21 but also the APP gene and FAD-linked markers. Extending from the anonymous DNA locus D21S52 to ETS2, the linkage map of six loci spans 39% recombination in man but only 6.4% recombination in the mouse. A break in synteny occurs distal to ETS2, with the homologue of the human marker D21S56 mapping to mouse chromosome 17. Conservation of the linkage relationships of markers in the FAD region suggests that the murine homologue of the FAD locus probably maps to chromosome 16 and that detailed comparison of the corresponding region in both species could facilitate identification of the primary defect in this disorder. The break in synteny between the terminal portion of human chromosome 21 and mouse chromosome 16 indicates, however, that mouse trisomy 16 may not represent a complete model of DS.

Bird-like sex chromosomes of platypus imply recent origin of mammal sex chromosomes.

PubMed

Veyrunes, Frédéric; Waters, Paul D; Miethke, Pat; Rens, Willem; McMillan, Daniel; Alsop, Amber E; Grützner, Frank; Deakin, Janine E; Whittington, Camilla M; Schatzkamer, Kyriena; Kremitzki, Colin L; Graves, Tina; Ferguson-Smith, Malcolm A; Warren, Wes; Marshall Graves, Jennifer A

2008-06-01

In therian mammals (placentals and marsupials), sex is determined by an XX female: XY male system, in which a gene (SRY) on the Y affects male determination. There is no equivalent in other amniotes, although some taxa (notably birds and snakes) have differentiated sex chromosomes. Birds have a ZW female: ZZ male system with no homology with mammal sex chromosomes, in which dosage of a Z-borne gene (possibly DMRT1) affects male determination. As the most basal mammal group, the egg-laying monotremes are ideal for determining how the therian XY system evolved. The platypus has an extraordinary sex chromosome complex, in which five X and five Y chromosomes pair in a translocation chain of alternating X and Y chromosomes. We used physical mapping to identify genes on the pairing regions between adjacent X and Y chromosomes. Most significantly, comparative mapping shows that, contrary to earlier reports, there is no homology between the platypus and therian X chromosomes. Orthologs of genes in the conserved region of the human X (including SOX3, the gene from which SRY evolved) all map to platypus chromosome 6, which therefore represents the ancestral autosome from which the therian X and Y pair derived. Rather, the platypus X chromosomes have substantial homology with the bird Z chromosome (including DMRT1) and to segments syntenic with this region in the human genome. Thus, platypus sex chromosomes have strong homology with bird, but not to therian sex chromosomes, implying that the therian X and Y chromosomes (and the SRY gene) evolved from an autosomal pair after the divergence of monotremes only 166 million years ago. Therefore, the therian X and Y are more than 145 million years younger than previously thought.

Homozygosity Mapping Identifies an Additional Locus for Wolfram Syndrome on Chromosome 4q

PubMed Central

El-Shanti, Hatem; Lidral, Andrew C.; Jarrah, Nadim; Druhan, Lawrence; Ajlouni, Kamel

2000-01-01

Wolfram syndrome, which is sometimes referred to as “DIDMOAD” (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness), is an autosomal recessive neurodegenerative disorder for which only insulin-dependent diabetes mellitus and optic atrophy are necessary to make the diagnosis. Researchers have mapped Wolfram syndrome to chromosome 4p16.1, and, recently, a gene encoding a putative transmembrane protein has been cloned and mutations have been identified in patients. To pursue the possibility of locus heterogeneity, 16 patients from four different families were recruited. These patients, who have the Wolfram syndrome phenotype, also have additional features that have not previously been reported. There is an absence of diabetes insipidus in all affected family members. In addition, several patients have profound upper gastrointestinal ulceration and bleeding. With the use of three microsatellite markers (D4S432, D4S3023, and D4S2366) reported to be linked to the chromosome 4p16.1 locus, we significantly excluded linkage in three of the four families. The two affected individuals in one family showed homozygosity for all three markers from the region of linkage on chromosome 4p16.1. For the other three families, genetic heterogeneity for Wolfram syndrome was verified by demonstration of linkage to chromosome 4q22-24. In conclusion, we report the unique clinical findings and linkage-analysis results of 16 patients with Wolfram syndrome and provide further evidence for the genetic heterogeneity of this disorder. We also provide data on a new locus that plays a role in the etiology of insulin-dependent diabetes mellitus. PMID:10739754

Identification and characterization of genomic regions on chromosomes 4 and 8 that control the rate of photosynthesis in rice leaves

PubMed Central

Adachi, Shunsuke; Tsuru, Yukiko; Nito, Naoko; Murata, Kazumasa; Yamamoto, Toshio; Ebitani, Takeshi; Ookawa, Taiichiro; Hirasawa, Tadashi

2011-01-01

DNA marker-assisted selection appears to be a promising strategy for improving rates of leaf photosynthesis in rice. The rate of leaf photosynthesis was significantly higher in a high-yielding indica variety, Habataki, than in the most popular Japanese variety, Koshihikari, at the full heading stage as a result of the higher level of leaf nitrogen at the same rate of application of nitrogen and the higher stomatal conductance even when the respective levels of leaf nitrogen were the same. The higher leaf nitrogen content of Habataki was caused by the greater accumulation of nitrogen by plants. The higher stomatal conductance of Habataki was caused by the higher hydraulic conductance. Using progeny populations and selected lines derived from a cross between Koshihikari and Habataki, it was possible to identify the genomic regions responsible for the rate of photosynthesis within a 2.1 Mb region between RM17459 and RM17552 and within a 1.2 Mb region between RM6999 and RM22529 on the long arm of chromosome 4 and on the short arm of chromosome 8, respectively. The designated region on chromosome 4 of Habataki was responsible for both the increase in the nitrogen content of leaves and hydraulic conductance in the plant by increasing the root surface area. The designated region on chromosome 8 of Habataki was responsible for the increase in hydraulic conductance by increasing the root hydraulic conductivity. The results suggest that it may be possible to improve photosynthesis in rice leaves by marker-assisted selection that focuses on these regions of chromosomes 4 and 8. PMID:21296764

Deciphering evolutionary strata on plant sex chromosomes and fungal mating-type chromosomes through compositional segmentation.

PubMed

Pandey, Ravi S; Azad, Rajeev K

2016-03-01

Sex chromosomes have evolved from a pair of homologous autosomes which differentiated into sex determination systems, such as XY or ZW system, as a consequence of successive recombination suppression between the gametologous chromosomes. Identifying the regions of recombination suppression, namely, the "evolutionary strata", is central to understanding the history and dynamics of sex chromosome evolution. Evolution of sex chromosomes as a consequence of serial recombination suppressions is well-studied for mammals and birds, but not for plants, although 48 dioecious plants have already been reported. Only two plants Silene latifolia and papaya have been studied until now for the presence of evolutionary strata on their X chromosomes, made possible by the sequencing of sex-linked genes on both the X and Y chromosomes, which is a requirement of all current methods that determine stratum structure based on the comparison of gametologous sex chromosomes. To circumvent this limitation and detect strata even if only the sequence of sex chromosome in the homogametic sex (i.e. X or Z chromosome) is available, we have developed an integrated segmentation and clustering method. In application to gene sequences on the papaya X chromosome and protein-coding sequences on the S. latifolia X chromosome, our method could decipher all known evolutionary strata, as reported by previous studies. Our method, after validating on known strata on the papaya and S. latifolia X chromosome, was applied to the chromosome 19 of Populus trichocarpa, an incipient sex chromosome, deciphering two, yet unknown, evolutionary strata. In addition, we applied this approach to the recently sequenced sex chromosome V of the brown alga Ectocarpus sp. that has a haploid sex determination system (UV system) recovering the sex determining and pseudoautosomal regions, and then to the mating-type chromosomes of an anther-smut fungus Microbotryum lychnidis-dioicae predicting five strata in the non

Comparative mapping of DNA markers from the familial Alzheimer disease and Down syndrome regions of human chromosome 21 to mouse chromosomes 16 and 17

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, S.V.; Nadeau, J.H.; Tanzi, R.E.

1988-08-01

Mouse trisomy 16 has been proposed as an animal model of Down syndrome (DS), since this chromosome contains homologues of several loci from the q22 band of human chromosome 21. The recent mapping of the defect causing familial Alzheimer disease (FAD) and the locus encoding the Alzheimer amyloid {beta} precursor protein (APP) to human chromosome 21 has prompted a more detailed examination of the extent of conservation of this linkage group between the two species. Using anonymous DNA probes and cloned genes from human chromosome 21 in a combination of recombinant inbred and interspecific mouse backcross analyses, the authors havemore » established that the linkage group shared by mouse chromosome 16 includes not only the critical DS region of human chromosome 21 but also the APP gene and FAD-linked markers. Extending from the anonymous DNA locus D21S52 to ETS2, the linkage map of six loci spans 39% recombination in man but only 6.4% recombination in the mouse. A break in synteny occurs distal to ETS2, with the homologue of the human marker D21S56 mapping to mouse chromosome 17. Conservation of the linkage relationships of markers in the FAD region suggests that the murine homologue of the FAD locus probably maps to chromosome 16 and that detailed comparison of the corresponding region in both species could facilitate identification of the primary defect in this disorder. The break in synteny between the terminal portion of human chromosome 21 and mouse chromosome 16 indicates, however, that mouse trisomy 16 may not represent a complete model of DS.« less

Correlation approach to identify coding regions in DNA sequences

NASA Technical Reports Server (NTRS)

Ossadnik, S. M.; Buldyrev, S. V.; Goldberger, A. L.; Havlin, S.; Mantegna, R. N.; Peng, C. K.; Simons, M.; Stanley, H. E.

1994-01-01

Recently, it was observed that noncoding regions of DNA sequences possess long-range power-law correlations, whereas coding regions typically display only short-range correlations. We develop an algorithm based on this finding that enables investigators to perform a statistical analysis on long DNA sequences to locate possible coding regions. The algorithm is particularly successful in predicting the location of lengthy coding regions. For example, for the complete genome of yeast chromosome III (315,344 nucleotides), at least 82% of the predictions correspond to putative coding regions; the algorithm correctly identified all coding regions larger than 3000 nucleotides, 92% of coding regions between 2000 and 3000 nucleotides long, and 79% of coding regions between 1000 and 2000 nucleotides. The predictive ability of this new algorithm supports the claim that there is a fundamental difference in the correlation property between coding and noncoding sequences. This algorithm, which is not species-dependent, can be implemented with other techniques for rapidly and accurately locating relatively long coding regions in genomic sequences.

Amplifications of chromosomal region 20q13 as a prognostic indicator breast cancer

DOEpatents

Gray, Joe W.; Collins, Colin; Pinkel, Daniel; Kallioniemi, Olli-Pekka; Tanner, Minna M.

2001-01-01

The present invention relates to in situ hybridization methods for the identification of new chromosomal abnormalities associated with various diseases. In particular, it provides probes which are specific to a region of amplification in chromosome 20.

Chromosome Rearrangements That Involve the Nucleolus Organizer Region in Neurospora

PubMed Central

Perkins, D. D.; Raju, N. B.; Barry, E. G.; Butler, D. K.

1995-01-01

In ~3% of Neurospora crassa rearrangements, part of a chromosome arm becomes attached to the nucleolus organizer region (NOR) at one end of chromosome 2 (linkage group V). Investigations with one inversion and nine translocations of this type are reported here. They appear genetically to be nonreciprocal and terminal. When a rearrangement is heterozygous, about one-third of viable progeny are segmental aneuploids with the translocated segment present in two copies, one in normal position and one associated with the NOR. Duplications from many of the rearrangements are highly unstable, breaking down by loss of the NOR-attached segment to restore normal chromosome sequence. When most of the rearrangements are homozygous, attenuated strands can be seen extending through the unstained nucleolus at pachytene, joining the translocated distal segment to the remainder of chromosome 2. Although the rearrangements appear genetically to be nonreciprocal, molecular evidence shows that at least several of them are physically reciprocal, with a block of rDNA repeats translocated away from the NOR. Evidence that NOR-associated breakpoints are nonterminal is also provided by intercrosses between pairs of translocations that transfer different-length segments of the same donor-chromosome arm to the NOR. PMID:8582636

The Guppy Sex Chromosome System and the Sexually Antagonistic Polymorphism Hypothesis for Y Chromosome Recombination Suppression

PubMed Central

Charlesworth, Deborah

2018-01-01

Sex chromosomes regularly evolve suppressed recombination, distinguishing them from other chromosomes, and the reason for this has been debated for many years. It is now clear that non-recombining sex-linked regions have arisen in different ways in different organisms. A major hypothesis is that a sex-determining gene arises on a chromosome and that sexually antagonistic (SA) selection (sometimes called intra-locus sexual conflict) acting at a linked gene has led to the evolution of recombination suppression in the region, to reduce the frequency of low fitness recombinant genotypes produced. The sex chromosome system of the guppy (Poecilia reticulata) is often cited as supporting this hypothesis because SA selection has been demonstrated to act on male coloration in natural populations of this fish, and probably contributes to maintaining polymorphisms for the genetic factors involved. I review classical genetic and new molecular genetic results from the guppy, and other fish, including approaches for identifying the genome regions carrying sex-determining loci, and suggest that the guppy may exemplify a recently proposed route to sex chromosome evolution. PMID:29783761

Identifying Potential Regions of Copy Number Variation for Bipolar Disorder

PubMed Central

Chen, Yi-Hsuan; Lu, Ru-Band; Hung, Hung; Kuo, Po-Hsiu

2014-01-01

Bipolar disorder is a complex psychiatric disorder with high heritability, but its genetic determinants are still largely unknown. Copy number variation (CNV) is one of the sources to explain part of the heritability. However, it is a challenge to estimate discrete values of the copy numbers using continuous signals calling from a set of markers, and to simultaneously perform association testing between CNVs and phenotypic outcomes. The goal of the present study is to perform a series of data filtering and analysis procedures using a DNA pooling strategy to identify potential CNV regions that are related to bipolar disorder. A total of 200 normal controls and 200 clinically diagnosed bipolar patients were recruited in this study, and were randomly divided into eight control and eight case pools. Genome-wide genotyping was employed using Illumina Human Omni1-Quad array with approximately one million markers for CNV calling. We aimed at setting a series of criteria to filter out the signal noise of marker data and to reduce the chance of false-positive findings for CNV regions. We first defined CNV regions for each pool. Potential CNV regions were reported based on the different patterns of CNV status between cases and controls. Genes that were mapped into the potential CNV regions were examined with association testing, Gene Ontology enrichment analysis, and checked with existing literature for their associations with bipolar disorder. We reported several CNV regions that are related to bipolar disorder. Two CNV regions on chromosome 11 and 22 showed significant signal differences between cases and controls (p < 0.05). Another five CNV regions on chromosome 6, 9, and 19 were overlapped with results in previous CNV studies. Experimental validation of two CNV regions lent some support to our reported findings. Further experimental and replication studies could be designed for these selected regions. PMID:27605030

P-Element Insertion Alleles of Essential Genes on the Third Chromosome of Drosophila Melanogaster: Correlation of Physical and Cytogenetic Maps in Chromosomal Region 86e-87f

PubMed Central

Deak, P.; Omar, M. M.; Saunders, RDC.; Pal, M.; Komonyi, O.; Szidonya, J.; Maroy, P.; Zhang, Y.; Ashburner, M.; Benos, P.; Savakis, C.; Siden-Kiamos, I.; Louis, C.; Bolshakov, V. N.; Kafatos, F. C.; Madueno, E.; Modolell, J.; Glover, D. M.

1997-01-01

We have established a collection of 2460 lethal or semi-lethal mutant lines using a procedure thought to insert single P elements into vital genes on the third chromosome of Drosophila melanogaster. More than 1200 randomly selected lines were examined by in situ hybridization and 90% found to contain single insertions at sites that mark 89% of all lettered subdivisions of the Bridges' map. A set of chromosomal deficiencies that collectively uncover ~25% of the euchromatin of chromosome 3 reveal lethal mutations in 468 lines corresponding to 145 complementation groups. We undertook a detailed analysis of the cytogenetic interval 86E-87F and identified 87 P-element-induced mutations falling into 38 complementation groups, 16 of which correspond to previously known genes. Twenty-one of these 38 complementation groups have at least one allele that has a P-element insertion at a position consistent with the cytogenetics of the locus. We have rescued P elements and flanking chromosomal sequences from the 86E-87F region in 35 lines with either lethal or genetically silent P insertions, and used these as probes to identify cosmids and P1 clones from the Drosophila genome projects. This has tied together the physical and genetic maps and has linked 44 previously identified cosmid contigs into seven ``supercontigs'' that span the interval. STS data for sequences flanking one side of the P-element insertions in 49 lines has identified insertions in the αγ element at 87C, two known transposable elements, and the open reading frames of seven putative single copy genes. These correspond to five known genes in this interval, and two genes identified by the homology of their predicted products to known proteins from other organisms. PMID:9409831

Erratum: Letter to the Editor: Exclusion of primary congenital glaucoma (buphthalmos) from two candidate regions of chromosome arm 6p and chromosome 11

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-03-01

This {open_quotes}Letter to the Editor{close_quotes} is the reprint of a corrected table from a previous paper about the exclusion of primary congenital glaucoma from two candidate regions of chromosome arm 6p and chromosome 11.

Association of Many Regions of the Bacillus subtilis Chromosome with the Cell Membrane

PubMed Central

Ivarie, Robert D.; Pène, Jacques J.

1973-01-01

Unsheared lysates of Bacillus subtilis 168T− containing uniformly labeled deoxyribonucleic acid (DNA) were exposed to varying doses of gamma rays to introduce double-strand scissions in the chromosome. From an estimate of the number-average molecular weight and the amount of DNA bound to membrane after irradiation, about 70 to 90 regions of the bacterial chromosome were detected in membrane fractions. Since this number was independent of the molecular weight of the DNA (i.e., the extent of fragmentation of the chromosome), it is thought to represent an upper limit in the number of membrane-binding sites per chromosome. PMID:4196245

Chromosome I duplications in Caenorhabditis elegans

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKim, K.S.; Rose, A.M.

1990-01-01

We have isolated and characterized 76 duplications of chromosome I in the genome of Caenorhabditis elegans. The region studied is the 20 map unit left half of the chromosome. Sixty-two duplications were induced with gamma radiation and 14 arose spontaneously. The latter class was apparently the result of spontaneous breaks within the parental duplication. The majority of duplications behave as if they are free. Three duplications are attached to identifiable sequences from other chromosomes. The duplication breakpoints have been mapped by complementation analysis relative to genes on chromosome I. Nineteen duplication breakpoints and seven deficiency breakpoints divide the left halfmore » of the chromosome into 24 regions. We have studied the relationship between duplication size and segregational stability. While size is an important determinant of mitotic stability, it is not the only one. We observed clear exceptions to a size-stability correlation. In addition to size, duplication stability may be influenced by specific sequences or chromosome structure. The majority of the duplications were stable enough to be powerful tools for gene mapping. Therefore the duplications described here will be useful in the genetic characterization of chromosome I and the techniques we have developed can be adapted to other regions of the genome.« less

Amplifications of chromosomal region 20q13 as a prognostic indicator in breast cancer

DOEpatents

Gray, Joe W.; Collins, Colin; Pinkel, Daniel; Kallioniemi, Olli-Pekka; Tanner, Minna M.

1998-01-01

The present invention relates to in situ hybridization methods for the identification of new chromosomal abnormalities associated with various diseases. In particular, it provides probes which are specific to a region of amplification in chromosome 20.

Abnormalities at chromosome region 3p12-14 characterize clear cell renal carcinoma.

PubMed

Carroll, P R; Murty, V V; Reuter, V; Jhanwar, S; Fair, W R; Whitmore, W F; Chaganti, R S

1987-06-01

In an effort to determine whether or not any characteristic chromosomal abnormalities exist in renal cancer, cytogenetic findings were correlated with tumor histology in nine cases of renal adenocarcinoma. Metaphase preparations adequate for analysis were obtained from cultures harvested between day 3 and day 21. Model chromosome number was diploid in three cases, hypodiploid in three, and hyperdiploid in the remaining three. One clear cell adenocarcinoma failed to reveal any chromosomal abnormality. Two tumors, a tubular/papillary carcinoma and an acinar/papillary carcinoma, showed the clonal abnormalities del(1)(p2l),+2,+7,+8,+12,+13,+16,+17,-21 and t(2;10)(q14-21;q26),+7q,+11q,-18, respectively. Interestingly, five of six clear cell tumors studied had clonal abnormalities affecting the short arm of chromosome #3 in the 3p12-21 region, and in the remaining case, of 15 karyotyped metaphases suitable for interpretation, one showed a deletion in 3p. These data indicate that clear cell carcinoma of the kidney may be associated with a nonrandom chromosomal abnormality involving the 3p12-14 region.

Y chromosome specific nucleic acid probe and method for identifying the Y chromosome in SITU

DOEpatents

Gray, Joe W.; Weier, Heinz-Ulrich

1999-01-01

A method for producing a Y chromosome specific probe selected from highly repeating sequences on that chromosome is described. There is little or no nonspecific binding to autosomal and X chromosomes, and a very large signal is provided. Inventive primers allowing the use of PCR for both sample amplification and probe production are described, as is their use in producing large DNA chromosome painting sequences.

Y chromosome specific nucleic acid probe and method for identifying the Y chromosome in SITU

DOEpatents

Gray, J.W.; Weier, H.U.

1999-03-30

A method for producing a Y chromosome specific probe selected from highly repeating sequences on that chromosome is described. There is little or no nonspecific binding to autosomal and X chromosomes, and a very large signal is provided. Inventive primers allowing the use of PCR for both sample amplification and probe production are described, as is their use in producing large DNA chromosome painting sequences. 9 figs.

Linkage group-chromosome correlations in Sordaria macrospora: Chromosome identification by three dimensional reconstruction of their synaptonemal complex.

PubMed

Zickler, D; Leblon, G; Haedens, V; Collard, A; Thuriaux, P

1984-01-01

Reconstruction of serially sectioned zygotene and pachytene nuclei has allowed, by measuring the lengths of synaptonemal complexes, an assignment of the 7 linkage (LG) groups to the 7 chromosomes in the fungus Sordaria macrospora. The 7 LG have been established using 19 mutants showing low second division segregation frequencies. Eight chromosomal rearrangements mapped on the 7 LG were used to identify the chromosomes involved. The following one to one assignment of the 7 LG to specific chromosomes was obtained: LG a: chromosome (chr) 1, LG b: chr5, LG c: chr6, LG d: chr7, LG e: chr4, LG f: chr3 and LG g: chr2 (the chromosome carrying the nucleolus organizer region).

Long-Read Single Molecule Sequencing to Resolve Tandem Gene Copies: The Mst77Y Region on the Drosophila melanogaster Y Chromosome

PubMed Central

Krsticevic, Flavia J.; Schrago, Carlos G.; Carvalho, A. Bernardo

2015-01-01

The autosomal gene Mst77F of Drosophila melanogaster is essential for male fertility. In 2010, Krsticevic et al. (Genetics 184: 295−307) found 18 Y-linked copies of Mst77F (“Mst77Y”), which collectively account for 20% of the functional Mst77F-like mRNA. The Mst77Y genes were severely misassembled in the then-available genome assembly and were identified by cloning and sequencing polymerase chain reaction products. The genomic structure of the Mst77Y region and the possible existence of additional copies remained unknown. The recent publication of two long-read assemblies of D. melanogaster prompted us to reinvestigate this challenging region of the Y chromosome. We found that the Illumina Synthetic Long Reads assembly failed in the Mst77Y region, most likely because of its tandem duplication structure. The PacBio MHAP assembly of the Mst77Y region seems to be very accurate, as revealed by comparisons with the previously found Mst77Y genes, a bacterial artificial chromosome sequence, and Illumina reads of the same strain. We found that the Mst77Y region spans 96 kb and originated from a 3.4-kb transposition from chromosome 3L to the Y chromosome, followed by tandem duplications inside the Y chromosome and invasion of transposable elements, which account for 48% of its length. Twelve of the 18 Mst77Y genes found in 2010 were confirmed in the PacBio assembly, the remaining six being polymerase chain reaction−induced artifacts. There are several identical copies of some Mst77Y genes, coincidentally bringing the total copy number to 18. Besides providing a detailed picture of the Mst77Y region, our results highlight the utility of PacBio technology in assembling difficult genomic regions such as tandemly repeated genes. PMID:25858959

A Genetic and Molecular Analysis of the 46c Chromosomal Region Surrounding the Fmrfamide Neuropeptide Gene in Drosophila Melanogaster

PubMed Central

O'Brien, M. A.; Roberts, M. S.; Taghert, P. H.

1994-01-01

We have analyzed the FMRFamide neuropeptide gene region of Drosophila melanogaster. This gene maps to the 46C region of chromosome 2R; this interval previously was not well characterized. For this genetic and molecular analysis, we have used X-ray mutagenesis, EMS mutagenesis, and the recently reported local P element transposition method. We identified four overlapping deletions, two of which have proximal breakpoints that define a 50-60-kb region surrounding the FMRFamide gene in 46C. To this small region, we mapped three lethal complementation groups; 10 additional lethal complementation groups were mapped to more distal regions of 46CD. One of these groups corresponds to even-skipped, the other 12 are previously unidentified. Using various lines of evidence we excluded the possibility that FMRFamide corresponds to any of the three lethal complementation groups mapping to its immediate 50-60-kb vicinity. The positions of two of the three lethal complementation groups were identified with P elements using a local transposition scheme. The third lethal complementation group was excluded as being FMRFamide mutants by sequence analysis and by immunocytochemistry with proFMRFamide precursor-specific antibodies. This analysis has (1) provided a genetic map of the 46CD chromosomal region and a detailed molecular map of a portion of the 46C region and (2) provided additional evidence of the utility of local transposition for targeting nearby genes. PMID:8056304

Familial isolated hyperparathyroidism is linked to a 1.7 Mb region on chromosome 2p13.3–14

PubMed Central

Warner, J; Nyholt, D R; Busfield, F; Epstein, M; Burgess, J; Stranks, S; Hill, P; Perry‐Keene, D; Learoyd, D; Robinson, B; Teh, B T; Prins, J B; Cardinal, J W

2006-01-01

Bachground Familial isolated hyperparathyroidism (FIHP) is an autosomal dominantly inherited form of primary hyperparathyroidism. Although comprising only about 1% of cases of primary hyperparathyroidism, identification and functional analysis of a causative gene for FIHP is likely to advance our understanding of parathyroid physiology and pathophysiology. Methods A genome‐wide screen of DNA from seven pedigrees with FIHP was undertaken in order to identify a region of genetic linkage with the disorder. Results Multipoint linkage analysis identified a region of suggestive linkage (LOD score 2.68) on chromosome 2. Fine mapping with the addition of three other families revealed significant linkage adjacent to D2S2368 (maximum multipoint LOD score 3.43). Recombination events defined a 1.7 Mb region of linkage between D2S2368 and D2S358 in nine pedigrees. Sequencing of the two most likely candidate genes in this region, however, did not identify a gene for FIHP. Conclusions We conclude that a causative gene for FIHP lies within this interval on chromosome 2. This is a major step towards eventual precise identification of a gene for FIHP, likely to be a key component in the genetic regulation of calcium homeostasis. PMID:16525030

Adipose and muscle tissue expression of two genes (NCAPG and LCORL) located in a chromosomal region associated with cattle feed intake and gain

USDA-ARS?s Scientific Manuscript database

A region on bovine chromosome 6 has been implicated in cattle birth weight, growth, and length. Non-SMC conodensin I complex subunit G (NCAPG) and ligand dependent nuclear receptor corepressor-like protein (LCORL) are positional candidate genes within this region. We previously identified genetic ...

Stable chromosome condensation revealed by chromosome conformation capture

PubMed Central

Eagen, Kyle P.; Hartl, Tom A.; Kornberg, Roger D.

2015-01-01

SUMMARY Chemical cross-linking and DNA sequencing have revealed regions of intra-chromosomal interaction, referred to as topologically associating domains (TADs), interspersed with regions of little or no interaction, in interphase nuclei. We find that TADs and the regions between them correspond with the bands and interbands of polytene chromosomes of Drosophila. We further establish the conservation of TADs between polytene and diploid cells of Drosophila. From direct measurements on light micrographs of polytene chromosomes, we then deduce the states of chromatin folding in the diploid cell nucleus. Two states of folding, fully extended fibers containing regulatory regions and promoters, and fibers condensed up to ten-fold containing coding regions of active genes, constitute the euchromatin of the nuclear interior. Chromatin fibers condensed up to 30-fold, containing coding regions of inactive genes, represent the heterochromatin of the nuclear periphery. A convergence of molecular analysis with direct observation thus reveals the architecture of interphase chromosomes. PMID:26544940

Genomic scan of selective sweeps in thin and fat tail sheep breeds for identifying of candidate regions associated with fat deposition

PubMed Central

2012-01-01

Background Identification of genomic regions that have been targets of selection for phenotypic traits is one of the most important and challenging areas of research in animal genetics. However, currently there are relatively few genomic regions identified that have been subject to positive selection. In this study, a genome-wide scan using ~50,000 Single Nucleotide Polymorphisms (SNPs) was performed in an attempt to identify genomic regions associated with fat deposition in fat-tail breeds. This trait and its modification are very important in those countries grazing these breeds. Results Two independent experiments using either Iranian or Ovine HapMap genotyping data contrasted thin and fat tail breeds. Population differentiation using FST in Iranian thin and fat tail breeds revealed seven genomic regions. Almost all of these regions overlapped with QTLs that had previously been identified as affecting fat and carcass yield traits in beef and dairy cattle. Study of selection sweep signatures using FST in thin and fat tail breeds sampled from the Ovine HapMap project confirmed three of these regions located on Chromosomes 5, 7 and X. We found increased homozygosity in these regions in favour of fat tail breeds on chromosome 5 and X and in favour of thin tail breeds on chromosome 7. Conclusions In this study, we were able to identify three novel regions associated with fat deposition in thin and fat tail sheep breeds. Two of these were associated with an increase of homozygosity in the fat tail breeds which would be consistent with selection for mutations affecting fat tail size several thousand years after domestication. PMID:22364287

Frequency of satellite association of human chromosomes is correlated with amount of Ag-staining of the nucleolus organizer region.

PubMed Central

Miller, D A; Tantravahi, R; Dev, V G; Miller, O J

1977-01-01

Methaphase chromosomes from karyotypically normal adult humans (three males, six females) and one male with a 13p - chromosome were stained by quinacrine and then by the Ag-AS silver staining method to reveal nucleolus organizer regions (NORs). Each person had a characteristic number of Ag-stained chromosomes per cell, always fewer than 10. Determination of the mean Ag-size of each chromosome showed that each of the 10 individuals had a unique distribution of Ag-stain. Within each individual, there was some variation from cell to cell in the number of acrocentric chromosomes that were Ag-stained; this was not random, and the same chromosomes (those that had at most a small amount of Ag-stain) tended to be unstained in every cell. Satellite associations were scored on the same cells. Chromosomes that had no Ag-stain were involved in satellite association less than 20% as often as those that had some Ag-stain. Chromosomes that had a small amount of Ag-stain were involved in association about 50% as often as those that had a large amount of stain. Regression analysis of the 50 (of a total of 100) acrocentric chromosomes which could be individually identified by quinacrine markers showed that the frequency with which a chromosome was involved in satellite association was strongly correlated with the amount of Ag-stained material in the NOR. Images Fig. 1 Fig. 3 PMID:70995

Meta-genome-wide association studies identify a locus on chromosome 1 and multiple variants in the MHC region for serum C-peptide in type 1 diabetes.

PubMed

Roshandel, Delnaz; Gubitosi-Klug, Rose; Bull, Shelley B; Canty, Angelo J; Pezzolesi, Marcus G; King, George L; Keenan, Hillary A; Snell-Bergeon, Janet K; Maahs, David M; Klein, Ronald; Klein, Barbara E K; Orchard, Trevor J; Costacou, Tina; Weedon, Michael N; Oram, Richard A; Paterson, Andrew D

2018-05-01

The aim of this study was to identify genetic variants associated with beta cell function in type 1 diabetes, as measured by serum C-peptide levels, through meta-genome-wide association studies (meta-GWAS). We performed a meta-GWAS to combine the results from five studies in type 1 diabetes with cross-sectionally measured stimulated, fasting or random C-peptide levels, including 3479 European participants. The p values across studies were combined, taking into account sample size and direction of effect. We also performed separate meta-GWAS for stimulated (n = 1303), fasting (n = 2019) and random (n = 1497) C-peptide levels. In the meta-GWAS for stimulated/fasting/random C-peptide levels, a SNP on chromosome 1, rs559047 (Chr1:238753916, T>A, minor allele frequency [MAF] 0.24-0.26), was associated with C-peptide (p = 4.13 × 10 -8 ), meeting the genome-wide significance threshold (p < 5 × 10 -8 ). In the same meta-GWAS, a locus in the MHC region (rs9260151) was close to the genome-wide significance threshold (Chr6:29911030, C>T, MAF 0.07-0.10, p = 8.43 × 10 -8 ). In the stimulated C-peptide meta-GWAS, rs61211515 (Chr6:30100975, T/-, MAF 0.17-0.19) in the MHC region was associated with stimulated C-peptide (β [SE] = - 0.39 [0.07], p = 9.72 × 10 -8 ). rs61211515 was also associated with the rate of stimulated C-peptide decline over time in a subset of individuals (n = 258) with annual repeated measures for up to 6 years (p = 0.02). In the meta-GWAS of random C-peptide, another MHC region, SNP rs3135002 (Chr6:32668439, C>A, MAF 0.02-0.06), was associated with C-peptide (p = 3.49 × 10 -8 ). Conditional analyses suggested that the three identified variants in the MHC region were independent of each other. rs9260151 and rs3135002 have been associated with type 1 diabetes, whereas rs559047 and rs61211515 have not been associated with a risk of developing type 1 diabetes. We identified a locus on

Fine mapping analysis confirms and strengthens linkage of four chromosomal regions in familial hypospadias

PubMed Central

Söderhäll, Cilla; Körberg, Izabella Baranowska; Thai, Hanh T T; Cao, Jia; Chen, Yougen; Zhang, Xufeng; Shulu, Zu; van der Zanden, Loes F M; van Rooij, Iris A L M; Frisén, Louise; Roeleveld, Nel; Markljung, Ellen; Kockum, Ingrid; Nordenskjöld, Agneta

2015-01-01

Hypospadias is a common male genital malformation and is regarded as a complex disease affected by multiple genetic as well as environmental factors. In a previous genome-wide scan for familial hypospadias, we reported suggestive linkage in nine chromosomal regions. We have extended this analysis by including new families and additional markers using non-parametric linkage. The fine mapping analysis displayed an increased LOD score on chromosome 8q24.1 and 10p15 in altogether 82 families. On chromosome 10p15, with the highest LOD score, we further studied AKR1C2, AKR1C3 and AKR1C4 involved in steroid metabolism, as well as KLF6 expressed in preputial tissue from hypospadias patients. Mutation analysis of the AKR1C3 gene showed a new mutation, c.643G>A (p.(Ala215Thr)), in a boy with penile hypospadias. This mutation is predicted to have an impact on protein function and structure and was not found in controls. Altogether, we homed in on four chromosomal regions likely to harbor genes for hypospadias. Future studies will aim for studying regulatory sequence variants in these regions. PMID:24986825

Adipose and muscle tissue gene expression of two genes (NCAPG and LCORL) located in a chromosomal region associated with cattle feed intake and gain

USDA-ARS?s Scientific Manuscript database

A region on bovine chromosome 6 has been implicated in cattle birth weight, growth, and length. Non-SMC conodensin I complex subunit G (NCAPG) and ligand dependent nuclear receptor corepressor-like protein (LCORL) are positional candidate genes within this region. Previously identified genetic mark...

Fine organization of genomic regions tagged to the 5S rDNA locus of the bread wheat 5B chromosome.

PubMed

Sergeeva, Ekaterina M; Shcherban, Andrey B; Adonina, Irina G; Nesterov, Michail A; Beletsky, Alexey V; Rakitin, Andrey L; Mardanov, Andrey V; Ravin, Nikolai V; Salina, Elena A

2017-11-14

The multigene family encoding the 5S rRNA, one of the most important structurally-functional part of the large ribosomal subunit, is an obligate component of all eukaryotic genomes. 5S rDNA has long been a favored target for cytological and phylogenetic studies due to the inherent peculiarities of its structural organization, such as the tandem arrays of repetitive units and their high interspecific divergence. The complex polyploid nature of the genome of bread wheat, Triticum aestivum, and the technically difficult task of sequencing clusters of tandem repeats mean that the detailed organization of extended genomic regions containing 5S rRNA genes remains unclear. This is despite the recent progress made in wheat genomic sequencing. Using pyrosequencing of BAC clones, in this work we studied the organization of two distinct 5S rDNA-tagged regions of the 5BS chromosome of bread wheat. Three BAC-clones containing 5S rDNA were identified in the 5BS chromosome-specific BAC-library of Triticum aestivum. Using the results of pyrosequencing and assembling, we obtained six 5S rDNA- containing contigs with a total length of 140,417 bp, and two sets (pools) of individual 5S rDNA sequences belonging to separate, but closely located genomic regions on the 5BS chromosome. Both regions are characterized by the presence of approximately 70-80 copies of 5S rDNA, however, they are completely different in their structural organization. The first region contained highly diverged short-type 5S rDNA units that were disrupted by multiple insertions of transposable elements. The second region contained the more conserved long-type 5S rDNA, organized as a single tandem array. FISH using probes specific to both 5S rDNA unit types showed differences in the distribution and intensity of signals on the chromosomes of polyploid wheat species and their diploid progenitors. A detailed structural organization of two closely located 5S rDNA-tagged genomic regions on the 5BS chromosome of bread

Fluorescent in situ hybridization shows DIPLOSPOROUS located on one of the NOR chromosomes in apomictic dandelions (Taraxacum) in the absence of a large hemizygous chromosomal region.

PubMed

Vašut, Radim J; Vijverberg, Kitty; van Dijk, Peter J; de Jong, Hans

2014-11-01

Apomixis in dandelions (Taraxacum: Asteraceae) is encoded by two unlinked dominant loci and a third yet undefined genetic factor: diplosporous omission of meiosis (DIPLOSPOROUS, DIP), parthenogenetic embryo development (PARTHENOGENESIS, PAR), and autonomous endosperm formation, respectively. In this study, we determined the chromosomal position of the DIP locus in Taraxacum by using fluorescent in situ hybridization (FISH) with bacterial artificial chromosomes (BACs) that genetically map within 1.2-0.2 cM of DIP. The BACs showed dispersed fluorescent signals, except for S4-BAC 83 that displayed strong unique signals as well. Under stringent blocking of repeats by C0t-DNA fragments, only a few fluorescent foci restricted to defined chromosome regions remained, including one on the nucleolus organizer region (NOR) chromosomes that contains the 45S rDNAs. FISH with S4-BAC 83 alone and optimal blocking showed discrete foci in the middle of the long arm of one of the NOR chromosomes only in triploid and tetraploid diplosporous dandelions, while signals in sexual diploids were lacking. This agrees with the genetic model of a single dose, dominant DIP allele, absent in sexuals. The length of the DIP region is estimated to cover a region of 1-10 Mb. FISH in various accessions of Taraxacum and the apomictic sister species Chondrilla juncea, confirmed the chromosomal position of DIP within Taraxacum but not outside the genus. Our results endorse that, compared to other model apomictic species, expressing either diplospory or apospory, the genome of Taraxacum shows a more similar and less diverged chromosome structure at the DIP locus. The different levels of allele sequence divergence at apomeiosis loci may reflect different terms of asexual reproduction. The association of apomeiosis loci with repetitiveness, dispersed repeats, and retrotransposons commonly observed in apomictic species may imply a functional role of these shared features in apomictic reproduction, as is

Genome-Wide Search Identifies 1.9 Mb from the Polar Bear Y Chromosome for Evolutionary Analyses

PubMed Central

Bidon, Tobias; Schreck, Nancy; Hailer, Frank; Nilsson, Maria A.; Janke, Axel

2015-01-01

The male-inherited Y chromosome is the major haploid fraction of the mammalian genome, rendering Y-linked sequences an indispensable resource for evolutionary research. However, despite recent large-scale genome sequencing approaches, only a handful of Y chromosome sequences have been characterized to date, mainly in model organisms. Using polar bear (Ursus maritimus) genomes, we compare two different in silico approaches to identify Y-linked sequences: 1) Similarity to known Y-linked genes and 2) difference in the average read depth of autosomal versus sex chromosomal scaffolds. Specifically, we mapped available genomic sequencing short reads from a male and a female polar bear against the reference genome and identify 112 Y-chromosomal scaffolds with a combined length of 1.9 Mb. We verified the in silico findings for the longer polar bear scaffolds by male-specific in vitro amplification, demonstrating the reliability of the average read depth approach. The obtained Y chromosome sequences contain protein-coding sequences, single nucleotide polymorphisms, microsatellites, and transposable elements that are useful for evolutionary studies. A high-resolution phylogeny of the polar bear patriline shows two highly divergent Y chromosome lineages, obtained from analysis of the identified Y scaffolds in 12 previously published male polar bear genomes. Moreover, we find evidence of gene conversion among ZFX and ZFY sequences in the giant panda lineage and in the ancestor of ursine and tremarctine bears. Thus, the identification of Y-linked scaffold sequences from unordered genome sequences yields valuable data to infer phylogenomic and population-genomic patterns in bears. PMID:26019166

Role of the tau gene region chromosome inversion in progressive supranuclear palsy, corticobasal degeneration, and related disorders.

PubMed

Webb, Amy; Miller, Bruce; Bonasera, Stephen; Boxer, Adam; Karydas, Anna; Wilhelmsen, Kirk C

2008-11-01

An inverted region on chromosome 17 has been previously linked to many Pick complex diseases. Due to the inversion, an exact causal locus has been difficult to identify, but the microtubule-associated protein tau gene is a likely candidate gene for its involvement in these diseases with tau inclusion. To search for variants that confer susceptibility to 4 tauopathies and clinically related disorders. Genomewide association study. University research laboratory. A total of 231 samples were genotyped from an unrelated white population of patients with progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), frontotemporal dementia, and frontotemporal dementia with amyotrophy. Unaffected individuals from the same population were used as controls. The results from an inverted region of chromosome 17 that contains the MAPT gene. Genotypes of cases and controls were compared using a Fisher exact test on a marker-by-marker basis. Haplotypes were determined by visually inspecting genotypes. Comparing any particular disease and controls, the association was constant across the inverted chromosome segment. Significant associations were seen for PSP and PSP combined with CBD. Of the 2 haplotypes seen in the region, H1 was overrepresented in PSP and CBD cases compared with controls. As expected, the markers are highly correlated and the association is seen across the entire region, which makes it difficult to narrow down a disease-causing variant or even a possible candidate gene. However, considering the pathologic abnormalities of these diseases and the involvement of tau mutations seen in familial forms, the MAPT gene represents the most likely cause driving the association.

Origin and domestication of papaya Yh chromosome

PubMed Central

VanBuren, Robert; Zeng, Fanchang; Chen, Cuixia; Zhang, Jisen; Wai, Ching Man; Han, Jennifer; Aryal, Rishi; Gschwend, Andrea R.; Wang, Jianping; Na, Jong-Kuk; Huang, Lixian; Zhang, Lingmao; Miao, Wenjing; Gou, Jiqing; Arro, Jie; Guyot, Romain; Moore, Richard C.; Wang, Ming-Li; Zee, Francis; Charlesworth, Deborah; Moore, Paul H.; Yu, Qingyi; Ming, Ray

2015-01-01

Sex in papaya is controlled by a pair of nascent sex chromosomes. Females are XX, and two slightly different Y chromosomes distinguish males (XY) and hermaphrodites (XYh). The hermaphrodite-specific region of the Yh chromosome (HSY) and its X chromosome counterpart were sequenced and analyzed previously. We now report the sequence of the entire male-specific region of the Y (MSY). We used a BAC-by-BAC approach to sequence the MSY and resequence the Y regions of 24 wild males and the Yh regions of 12 cultivated hermaphrodites. The MSY and HSY regions have highly similar gene content and structure, and only 0.4% sequence divergence. The MSY sequences from wild males include three distinct haplotypes, associated with the populations’ geographic locations, but gene flow is detected for other genomic regions. The Yh sequence is highly similar to one Y haplotype (MSY3) found only in wild dioecious populations from the north Pacific region of Costa Rica. The low MSY3-Yh divergence supports the hypothesis that hermaphrodite papaya is a product of human domestication. We estimate that Yh arose only ∼4000 yr ago, well after crop plant domestication in Mesoamerica >6200 yr ago but coinciding with the rise of the Maya civilization. The Yh chromosome has lower nucleotide diversity than the Y, or the genome regions that are not fully sex-linked, consistent with a domestication bottleneck. The identification of the ancestral MSY3 haplotype will expedite investigation of the mutation leading to the domestication of the hermaphrodite Yh chromosome. In turn, this mutation should identify the gene that was affected by the carpel-suppressing mutation that was involved in the evolution of males. PMID:25762551

Ulcerative colitis loci on chromosomes 1p36 and 12q15 identified by genome-wide association study

PubMed Central

Silverberg, Mark S.; Cho, Judy H.; Rioux, John D.; McGovern, Dermot P.B.; Wu, Jing; Annese, Vito; Achkar, Jean-Paul; Goyette, Philippe; Scott, Regan; Xu, Wei; Barmada, M. Michael; Klei, Lambertus; Daly, Mark J.; Abraham, Clara; Bayless, Theodore M.; Bossa, Fabrizio; Griffiths, Anne M.; Ippoliti, Andrew F.; Lahaie, Raymond G.; Latiano, Anna; Paré, Pierre; Proctor, Deborah D.; Regueiro, Miguel D.; Steinhart, A. Hillary; Targan, Stephan R.; Schumm, L. Philip; Kistner, Emily O.; Lee, Annette T.; Gregersen, Peter K.; Rotter, Jerome I.; Brant, Steven R.; Taylor, Kent D.; Roeder, Kathryn; Duerr, Richard H.

2008-01-01

Ulcerative colitis is a chronic inflammatory disease of the colon that presents as diarrhea and gastrointestinal bleeding. We performed a genome-wide association study using DNA samples from 1,052 individuals with ulcerative colitis and pre-existing data from 2,571 controls, all of European ancestry. In an analysis that controlled for gender and population structure, ulcerative colitis loci attaining genome-wide significance and subsequent replication in two independent populations were identified on chromosomes 1p36 (rs6426833, combined P = 5.1×10−13, combined OR = 0.73) and 12q15 (rs1558744, combined P = 2.5×10−12, combined OR = 1.35). In addition, combined genome-wide significant evidence for association was found in a region spanning BTNL2 to HLA-DQB1 on chromosome 6p21 (rs2395185, combined P = 1.0×10−16, combined OR = 0.66) and at the IL23R locus on chromosome 1p31 (rs11209026, combined P = 1.3×10−8, combined OR = 0.56; rs10889677, combined P = 1.3×10−8, combined OR = 1.29). PMID:19122664

Genome-Wide Search Identifies 1.9 Mb from the Polar Bear Y Chromosome for Evolutionary Analyses.

PubMed

Bidon, Tobias; Schreck, Nancy; Hailer, Frank; Nilsson, Maria A; Janke, Axel

2015-05-27

The male-inherited Y chromosome is the major haploid fraction of the mammalian genome, rendering Y-linked sequences an indispensable resource for evolutionary research. However, despite recent large-scale genome sequencing approaches, only a handful of Y chromosome sequences have been characterized to date, mainly in model organisms. Using polar bear (Ursus maritimus) genomes, we compare two different in silico approaches to identify Y-linked sequences: 1) Similarity to known Y-linked genes and 2) difference in the average read depth of autosomal versus sex chromosomal scaffolds. Specifically, we mapped available genomic sequencing short reads from a male and a female polar bear against the reference genome and identify 112 Y-chromosomal scaffolds with a combined length of 1.9 Mb. We verified the in silico findings for the longer polar bear scaffolds by male-specific in vitro amplification, demonstrating the reliability of the average read depth approach. The obtained Y chromosome sequences contain protein-coding sequences, single nucleotide polymorphisms, microsatellites, and transposable elements that are useful for evolutionary studies. A high-resolution phylogeny of the polar bear patriline shows two highly divergent Y chromosome lineages, obtained from analysis of the identified Y scaffolds in 12 previously published male polar bear genomes. Moreover, we find evidence of gene conversion among ZFX and ZFY sequences in the giant panda lineage and in the ancestor of ursine and tremarctine bears. Thus, the identification of Y-linked scaffold sequences from unordered genome sequences yields valuable data to infer phylogenomic and population-genomic patterns in bears. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Common regions of deletion in chromosome regions 3p12 and 3p14.2 in primary clear cell renal carcinomas.

PubMed

Lubinski, J; Hadaczek, P; Podolski, J; Toloczko, A; Sikorski, A; McCue, P; Druck, T; Huebner, K

1994-07-15

Nearly all clear cell renal cell carcinomas (RCCs) exhibit loss of alleles on the short arm of chromosome 3. Loss and mutation at the von Hippel-Lindau (VHL) gene at 3p25 probably occurs in most RCCs and, since the VHL gene was recently cloned, data on VHL involvement in RCCs is accumulating. However, the region 3p14-p12, a region that contains the familial RCC-associated t(3;8)(p14.2;q24) chromosome translocation and the small cell lung carcinoma-associated homozygous deletion at 3p13-12, has also been reported to exhibit allele loss in a large fraction of RCCs. In order to focus future studies on potential suppressor genes in the 3p14-p12 region, we have studied allele loss in 30 RCCs with 9 polymorphic simple sequence repeat markers spanning 3p21.1-p12. Partial losses in the 3p21-p12 region were observed, allowing determination of common regions of loss of heterozygosity overlap in 15 RCCs. Results suggested that most RCCs exhibit loss in a region which brackets the t(3;8) familial chromosome translocation at 3p14.2, and some show additional deletions within the U2020 small cell lung carcinoma deletion at 3p12.

Comprehensive multi-stage linkage analyses identify a locus for adult height on chromosome 3p in a healthy Caucasian population.

PubMed

Ellis, Justine A; Scurrah, Katrina J; Duncan, Anna E; Lamantia, Angela; Byrnes, Graham B; Harrap, Stephen B

2007-04-01

There have been a number of genome-wide linkage studies for adult height in recent years. These studies have yielded few well-replicated loci, and none have been further confirmed by the identification of associated gene variants. The inconsistent results may be attributable to the fact that few studies have combined accurate phenotype measures with informative statistical modelling in healthy populations. We have performed a multi-stage genome-wide linkage analysis for height in 275 adult sibling pairs drawn randomly from the Victorian Family Heart Study (VFHS), a healthy population-based Caucasian cohort. Height was carefully measured in a standardised fashion on regularly calibrated equipment. Following genome-wide identification of a peak Z-score of 3.14 on chromosome 3 at 69 cM, we performed a fine-mapping analysis of this region in an extended sample of 392 two-generation families. We used a number of variance components models that incorporated assortative mating and shared environment effects, and we observed a peak LOD score of approximately 3.5 at 78 cM in four of the five models tested. We also demonstrated that the most prevalent model in the literature gave the worst fit, and the lowest LOD score (2.9) demonstrating the importance of appropriate modelling. The region identified in this study replicates the results of other genome-wide scans of height and bone-related phenotypes, strongly suggesting the presence of a gene important in bone growth on chromosome 3p. Association analyses of relevant candidate genes should identify the genetic variants responsible for the chromosome 3p linkage signal in our population.

Origin and domestication of papaya Yh chromosome.

PubMed

VanBuren, Robert; Zeng, Fanchang; Chen, Cuixia; Zhang, Jisen; Wai, Ching Man; Han, Jennifer; Aryal, Rishi; Gschwend, Andrea R; Wang, Jianping; Na, Jong-Kuk; Huang, Lixian; Zhang, Lingmao; Miao, Wenjing; Gou, Jiqing; Arro, Jie; Guyot, Romain; Moore, Richard C; Wang, Ming-Li; Zee, Francis; Charlesworth, Deborah; Moore, Paul H; Yu, Qingyi; Ming, Ray

2015-04-01

Sex in papaya is controlled by a pair of nascent sex chromosomes. Females are XX, and two slightly different Y chromosomes distinguish males (XY) and hermaphrodites (XY(h)). The hermaphrodite-specific region of the Y(h) chromosome (HSY) and its X chromosome counterpart were sequenced and analyzed previously. We now report the sequence of the entire male-specific region of the Y (MSY). We used a BAC-by-BAC approach to sequence the MSY and resequence the Y regions of 24 wild males and the Y(h) regions of 12 cultivated hermaphrodites. The MSY and HSY regions have highly similar gene content and structure, and only 0.4% sequence divergence. The MSY sequences from wild males include three distinct haplotypes, associated with the populations' geographic locations, but gene flow is detected for other genomic regions. The Y(h) sequence is highly similar to one Y haplotype (MSY3) found only in wild dioecious populations from the north Pacific region of Costa Rica. The low MSY3-Y(h) divergence supports the hypothesis that hermaphrodite papaya is a product of human domestication. We estimate that Y(h) arose only ∼ 4000 yr ago, well after crop plant domestication in Mesoamerica >6200 yr ago but coinciding with the rise of the Maya civilization. The Y(h) chromosome has lower nucleotide diversity than the Y, or the genome regions that are not fully sex-linked, consistent with a domestication bottleneck. The identification of the ancestral MSY3 haplotype will expedite investigation of the mutation leading to the domestication of the hermaphrodite Y(h) chromosome. In turn, this mutation should identify the gene that was affected by the carpel-suppressing mutation that was involved in the evolution of males. © 2015 VanBuren et al.; Published by Cold Spring Harbor Laboratory Press.

Fluorescence in situ hybridization evaluation of chromosome deletion patterns in prostate cancer.

PubMed

Huang, S F; Xiao, S; Renshaw, A A; Loughlin, K R; Hudson, T J; Fletcher, J A

1996-11-01

Various nonrandom chromosomal aberrations have been identified in prostate carcinoma. These aberrations include deletions of several chromosome regions, particularly the chromosome 8 short arm. Large-scale numerical aberrations, reflected in aberrant DNA ploidy, are also found in a minority of cases. However, it is unclear whether prostate carcinomas contain aberrations of certain chromosome regions that are deleted frequently in other common types of cancer. In this study, we performed dual-color fluorescence in situ hybridization on intact nuclei from touch preparations of 16 prostate cancers. Chromosome copy number was determined using pericentromeric probes, whereas potential chromosome arm deletions were evaluated using yeast artificial chromosome (YAC) and P1 probes. Two YAC probes targeted chromosome 8 short arm regions known to be deleted frequently in prostate cancer. Other YACs and P1s were for chromosome regions, including 1p22, 3p14, 6q21, 9p21, and 22q12, that are deletion targets in a variety of cancers although not extensively studied in prostate cancer. Hybridization efficiencies and signal intensities were excellent for both repeat sequence (alpha-satellite) and single, copy (YAC and P1) fluorescence in situ hybridization probes. Of 16 prostate cancers, 11 had clonal aberrations of 1 or more of the 13 chromosome regions evaluated, and 10 cases (62.5%) had 8p deletions, including 4 cases with 8p deletion in virtually all cells and aneuploidy in only a subset of those deleted cells. Deletions at 3p14, 6q21, and 22q12 were identified in 2, 1, and 1 case, respectively, and each of those cases had a similarly sized cell population with 8p deletion. These studies confirm 8p deletion in the majority of prostate carcinomas. 8p deletions appear to be early events in prostate tumorigenesis, often antedating aneuploidy. Fluorescence in situ hybridization strategies incorporating pericentromeric and single-copy regional chromosome probes offer a powerful and

Identification of ovule transcripts from the Apospory-Specific Genomic Region (ASGR)-carrier chromosome

PubMed Central

2011-01-01

Background Apomixis, asexual seed production in plants, holds great potential for agriculture as a means to fix hybrid vigor. Apospory is a form of apomixis where the embryo develops from an unreduced egg that is derived from a somatic nucellar cell, the aposporous initial, via mitosis. Understanding the molecular mechanism regulating aposporous initial specification will be a critical step toward elucidation of apomixis and also provide insight into developmental regulation and downstream signaling that results in apomixis. To discover candidate transcripts for regulating aposporous initial specification in P. squamulatum, we compared two transcriptomes derived from microdissected ovules at the stage of aposporous initial formation between the apomictic donor parent, P. squamulatum (accession PS26), and an apomictic derived backcross 8 (BC8) line containing only the Apospory-Specific Genomic Region (ASGR)-carrier chromosome from P. squamulatum. Toward this end, two transcriptomes derived from ovules of an apomictic donor parent and its apomictic backcross derivative at the stage of apospory initiation, were sequenced using 454-FLX technology. Results Using 454-FLX technology, we generated 332,567 reads with an average read length of 147 base pairs (bp) for the PS26 ovule transcriptome library and 363,637 reads with an average read length of 142 bp for the BC8 ovule transcriptome library. A total of 33,977 contigs from the PS26 ovule transcriptome library and 26,576 contigs from the BC8 ovule transcriptome library were assembled using the Multifunctional Inertial Reference Assembly program. Using stringent in silico parameters, 61 transcripts were predicted to map to the ASGR-carrier chromosome, of which 49 transcripts were verified as ASGR-carrier chromosome specific. One of the alien expressed genes could be assigned as tightly linked to the ASGR by screening of apomictic and sexual F1s. Only one transcript, which did not map to the ASGR, showed expression

A comparative study of retrotransposons in the centromeric regions of A and B chromosomes of maize.

PubMed

Theuri, J; Phelps-Durr, T; Mathews, S; Birchler, J

2005-01-01

Bacterial Artificial Chromosomes (BACs) derived from the B chromosome, based on homology with the B specific sequence, were subcloned and sequenced. Analysis of DNA sequence data indicated the presence of 23 common retroelements, as well as novel sequences of B chromosome origin. Generally, where the same retrotransposon type was observed in both A and B chromosomes, there were more copies per unit of sequence in the B centromeric region (the major site of B repeat) than in the A centromere, except for Huck-1. Based on previous estimates of the age of the major burst of transposition into the maize genome, the oldest retrotransposons (Ji-6 and Tekay, approximately 5.0 and 5.2 million years ago, respectively) were found in the B centromere region only, while the next two oldest (Huck-1 and Opie-1) were found in both the A and B sequences. Phylogenetic analysis of Opie retroelements from both A and B centromeres indicated that some of the B Opie centromeric sequences share a more recent common ancestor with A Opie retroelements than they do with other B Opie centromeric sequences. These results imply that the supernumerary maize B chromosome has coexisted with the A chromosomes during that period of transposition. They also support the hypothesis that the B chromosome had its origins from A chromosome elements, or that alternative origins, such as being donated to the maize genome in a wide species cross, preceded six million years ago, because the spectrum of retrotransposons in the two chromosomes is quite similar.

Identification and genetic mapping of a homeobox gene to the 4p16. 1 region of human chromosome 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stadler, H.S.; Padanilam, B.J.; Solursh, M.

1992-12-01

A human craniofacial cDNA library was screened with a degenerate oligonucleotide probe based on the conserved third helix of homeobox genes. From this screening, we identified a homeobox gene, H6, which shared only 57-65% amino acid identity to previously reported homeodomains. H6 was physically mapped to the 4P16.1 region by using somatic cell hybrids containing specific deletions of human chromosome 4. Linkage data from a single-stranded conformational polymorphism derived from the 3[prime] untranslated region of the H6 cDNA placed this homeobox gene more than 20 centimorgans proximal of the previously mapped HOX7 gene on chromosome 4. Identity comparisons of themore » H6 Homeodomain with previously reported homeodomains reveal the highest identities to be with the Nk class of homeobox genes in Drosophila melanogaster. 53 refs., 5 figs., 2 tabs.« less

Augmenting Chinese hamster genome assembly by identifying regions of high confidence.

PubMed

Vishwanathan, Nandita; Bandyopadhyay, Arpan A; Fu, Hsu-Yuan; Sharma, Mohit; Johnson, Kathryn C; Mudge, Joann; Ramaraj, Thiruvarangan; Onsongo, Getiria; Silverstein, Kevin A T; Jacob, Nitya M; Le, Huong; Karypis, George; Hu, Wei-Shou

2016-09-01

Chinese hamster Ovary (CHO) cell lines are the dominant industrial workhorses for therapeutic recombinant protein production. The availability of genome sequence of Chinese hamster and CHO cells will spur further genome and RNA sequencing of producing cell lines. However, the mammalian genomes assembled using shot-gun sequencing data still contain regions of uncertain quality due to assembly errors. Identifying high confidence regions in the assembled genome will facilitate its use for cell engineering and genome engineering. We assembled two independent drafts of Chinese hamster genome by de novo assembly from shotgun sequencing reads and by re-scaffolding and gap-filling the draft genome from NCBI for improved scaffold lengths and gap fractions. We then used the two independent assemblies to identify high confidence regions using two different approaches. First, the two independent assemblies were compared at the sequence level to identify their consensus regions as "high confidence regions" which accounts for at least 78 % of the assembled genome. Further, a genome wide comparison of the Chinese hamster scaffolds with mouse chromosomes revealed scaffolds with large blocks of collinearity, which were also compiled as high-quality scaffolds. Genome scale collinearity was complemented with EST based synteny which also revealed conserved gene order compared to mouse. As cell line sequencing becomes more commonly practiced, the approaches reported here are useful for assessing the quality of assembly and potentially facilitate the engineering of cell lines. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chromosome 17 alterations identify good-risk and poor-risk tumors independently of clinical factors in medulloblastoma

PubMed Central

McCabe, Martin G.; Bäcklund, L. Magnus; Leong, Hui Sun; Ichimura, Koichi; Collins, V. Peter

2011-01-01

Current risk stratification schemas for medulloblastoma, based on combinations of clinical variables and histotype, fail to accurately identify particularly good- and poor-risk tumors. Attempts have been made to improve discriminatory power by combining clinical variables with cytogenetic data. We report here a pooled analysis of all previous reports of chromosomal copy number related to survival data in medulloblastoma. We collated data from previous reports that explicitly quoted survival data and chromosomal copy number in medulloblastoma. We analyzed the relative prognostic significance of currently used clinical risk stratifiers and the chromosomal aberrations previously reported to correlate with survival. In the pooled dataset metastatic disease, incomplete tumor resection and severe anaplasia were associated with poor outcome, while young age at presentation was not prognostically significant. Of the chromosomal variables studied, isolated 17p loss and gain of 1q correlated with poor survival. Gain of 17q without associated loss of 17p showed a trend to improved outcome. The most commonly reported alteration, isodicentric chromosome 17, was not prognostically significant. Sequential multivariate models identified isolated 17p loss, isolated 17q gain, and 1q gain as independent prognostic factors. In a historical dataset, we have identified isolated 17p loss as a marker of poor outcome and 17q gain as a novel putative marker of good prognosis. Biological markers of poor-risk and good-risk tumors will be critical in stratifying treatment in future trials. Our findings should be prospectively validated independently in future clinical studies. PMID:21292688

Isolation and characterization of 21 novel expressed DNA sequences from the distal region of human chromosome 4p

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishida, Yoshikazu; Hadano, Shinji; Nagayama, Tomiko

1994-07-15

The authors have established an approach to the isolation of expressed DNA sequences from a defined region of the human chromosome. The method relies on the direct screening of cDNA libraries using pooled single-copy microclones generated by a laser chromosome microdissection in conjunction with a single unique primer polymerase chain reaction (SUP-PCR) procedure. They applied this method to the distal region of human chromosome 4p (4p15-4pter), which contains the Huntington disease (HD) and the Wolf-Hirschhorn syndrome (WHS) loci. Twenty-one nonoverlapping and region-specific cDNA clones encoding novel genes were isolated in this manner. Ten of 21 clones were subregionally assigned tomore » 4p16.1-4pter, and the remainder mapped to the region proximal to 4p16.1. Northern blot and reverse transcription followed by the PCR (RT-PCR) analysis revealed that 16 of these 21 clones detected transcripts in total RNA from human tissues. The method is applicable to other chromosomal regions and is a powerful approach to the isolation of region-specific cDNA clones. 44 refs., 3 figs., 3 tabs.« less

Sequencing papaya X and Yh chromosomes reveals molecular basis of incipient sex chromosome evolution

PubMed Central

Wang, Jianping; Na, Jong-Kuk; Yu, Qingyi; Gschwend, Andrea R.; Han, Jennifer; Zeng, Fanchang; Aryal, Rishi; VanBuren, Robert; Murray, Jan E.; Zhang, Wenli; Navajas-Pérez, Rafael; Feltus, F. Alex; Lemke, Cornelia; Tong, Eric J.; Chen, Cuixia; Man Wai, Ching; Singh, Ratnesh; Wang, Ming-Li; Min, Xiang Jia; Alam, Maqsudul; Charlesworth, Deborah; Moore, Paul H.; Jiang, Jiming; Paterson, Andrew H.; Ming, Ray

2012-01-01

Sex determination in papaya is controlled by a recently evolved XY chromosome pair, with two slightly different Y chromosomes controlling the development of males (Y) and hermaphrodites (Yh). To study the events of early sex chromosome evolution, we sequenced the hermaphrodite-specific region of the Yh chromosome (HSY) and its X counterpart, yielding an 8.1-megabase (Mb) HSY pseudomolecule, and a 3.5-Mb sequence for the corresponding X region. The HSY is larger than the X region, mostly due to retrotransposon insertions. The papaya HSY differs from the X region by two large-scale inversions, the first of which likely caused the recombination suppression between the X and Yh chromosomes, followed by numerous additional chromosomal rearrangements. Altogether, including the X and/or HSY regions, 124 transcription units were annotated, including 50 functional pairs present in both the X and HSY. Ten HSY genes had functional homologs elsewhere in the papaya autosomal regions, suggesting movement of genes onto the HSY, whereas the X region had none. Sequence divergence between 70 transcripts shared by the X and HSY revealed two evolutionary strata in the X chromosome, corresponding to the two inversions on the HSY, the older of which evolved about 7.0 million years ago. Gene content differences between the HSY and X are greatest in the older stratum, whereas the gene content and order of the collinear regions are identical. Our findings support theoretical models of early sex chromosome evolution. PMID:22869747

Sequencing papaya X and Yh chromosomes reveals molecular basis of incipient sex chromosome evolution.

PubMed

Wang, Jianping; Na, Jong-Kuk; Yu, Qingyi; Gschwend, Andrea R; Han, Jennifer; Zeng, Fanchang; Aryal, Rishi; VanBuren, Robert; Murray, Jan E; Zhang, Wenli; Navajas-Pérez, Rafael; Feltus, F Alex; Lemke, Cornelia; Tong, Eric J; Chen, Cuixia; Wai, Ching Man; Singh, Ratnesh; Wang, Ming-Li; Min, Xiang Jia; Alam, Maqsudul; Charlesworth, Deborah; Moore, Paul H; Jiang, Jiming; Paterson, Andrew H; Ming, Ray

2012-08-21

Sex determination in papaya is controlled by a recently evolved XY chromosome pair, with two slightly different Y chromosomes controlling the development of males (Y) and hermaphrodites (Y(h)). To study the events of early sex chromosome evolution, we sequenced the hermaphrodite-specific region of the Y(h) chromosome (HSY) and its X counterpart, yielding an 8.1-megabase (Mb) HSY pseudomolecule, and a 3.5-Mb sequence for the corresponding X region. The HSY is larger than the X region, mostly due to retrotransposon insertions. The papaya HSY differs from the X region by two large-scale inversions, the first of which likely caused the recombination suppression between the X and Y(h) chromosomes, followed by numerous additional chromosomal rearrangements. Altogether, including the X and/or HSY regions, 124 transcription units were annotated, including 50 functional pairs present in both the X and HSY. Ten HSY genes had functional homologs elsewhere in the papaya autosomal regions, suggesting movement of genes onto the HSY, whereas the X region had none. Sequence divergence between 70 transcripts shared by the X and HSY revealed two evolutionary strata in the X chromosome, corresponding to the two inversions on the HSY, the older of which evolved about 7.0 million years ago. Gene content differences between the HSY and X are greatest in the older stratum, whereas the gene content and order of the collinear regions are identical. Our findings support theoretical models of early sex chromosome evolution.

CENP-A and topoisomerase-II antagonistically affect chromosome length.

PubMed

Ladouceur, A-M; Ranjan, Rajesh; Smith, Lydia; Fadero, Tanner; Heppert, Jennifer; Goldstein, Bob; Maddox, Amy Shaub; Maddox, Paul S

2017-09-04

The size of mitotic chromosomes is coordinated with cell size in a manner dependent on nuclear trafficking. In this study, we conducted an RNA interference screen of the Caenorhabditis elegans nucleome in a strain carrying an exceptionally long chromosome and identified the centromere-specific histone H3 variant CENP-A and the DNA decatenizing enzyme topoisomerase-II (topo-II) as candidate modulators of chromosome size. In the holocentric organism C. elegans , CENP-A is positioned periodically along the entire length of chromosomes, and in mitosis, these genomic regions come together linearly to form the base of kinetochores. We show that CENP-A protein levels decreased through development coinciding with chromosome-size scaling. Partial loss of CENP-A protein resulted in shorter mitotic chromosomes, consistent with a role in setting chromosome length. Conversely, topo-II levels were unchanged through early development, and partial topo-II depletion led to longer chromosomes. Topo-II localized to the perimeter of mitotic chromosomes, excluded from the centromere regions, and depletion of topo-II did not change CENP-A levels. We propose that self-assembly of centromeric chromatin into an extended linear array promotes elongation of the chromosome, whereas topo-II promotes chromosome-length shortening. © 2017 Ladouceur et al.

First Pass Annotation of Promoters on Human Chromosome 22

PubMed Central

Scherf, Matthias; Klingenhoff, Andreas; Frech, Kornelie; Quandt, Kerstin; Schneider, Ralf; Grote, Korbinian; Frisch, Matthias; Gailus-Durner, Valérie; Seidel, Alexander; Brack-Werner, Ruth; Werner, Thomas

2001-01-01

The publication of the first almost complete sequence of a human chromosome (chromosome 22) is a major milestone in human genomics. Together with the sequence, an excellent annotation of genes was published which certainly will serve as an information resource for numerous future projects. We noted that the annotation did not cover regulatory regions; in particular, no promoter annotation has been provided. Here we present an analysis of the complete published chromosome 22 sequence for promoters. A recent breakthrough in specific in silico prediction of promoter regions enabled us to attempt large-scale prediction of promoter regions on chromosome 22. Scanning of sequence databases revealed only 20 experimentally verified promoters, of which 10 were correctly predicted by our approach. Nearly 40% of our 465 predicted promoter regions are supported by the currently available gene annotation. Promoter finding also provides a biologically meaningful method for “chromosomal scaffolding”, by which long genomic sequences can be divided into segments starting with a gene. As one example, the combination of promoter region prediction with exon/intron structure predictions greatly enhances the specificity of de novo gene finding. The present study demonstrates that it is possible to identify promoters in silico on the chromosomal level with sufficient reliability for experimental planning and indicates that a wealth of information about regulatory regions can be extracted from current large-scale (megabase) sequencing projects. Results are available on-line at http://genomatix.gsf.de/chr22/. PMID:11230158

PCR-based karyotyping of Anopheles gambiae inversion 2Rj identifies the BAMAKO chromosomal form.

PubMed

Coulibaly, Mamadou B; Pombi, Marco; Caputo, Beniamino; Nwakanma, Davis; Jawara, Musa; Konate, Lassana; Dia, Ibrahima; Fofana, Abdrahamane; Kern, Marcia; Simard, Frédéric; Conway, David J; Petrarca, Vincenzo; della Torre, Alessandra; Traoré, Sékou; Besansky, Nora J

2007-10-01

The malaria vector Anopheles gambiae is polymorphic for chromosomal inversions on the right arm of chromosome 2 that segregate nonrandomly between assortatively mating populations in West Africa. One such inversion, 2Rj, is associated with the BAMAKO chromosomal form endemic to southern Mali and northern Guinea Conakry near the Niger River. Although it exploits a unique ecology and both molecular and chromosomal data suggest reduced gene flow between BAMAKO and other A. gambiae populations, no molecular markers exist to identify this form. To facilitate study of the BAMAKO form, a PCR assay for molecular karyotyping of 2Rj was developed based on sequences at the breakpoint junctions. The assay was extensively validated using more than 700 field specimens whose karyotypes were determined in parallel by cytogenetic and molecular methods. As inversion 2Rj also occurs in SAVANNA populations outside the geographic range of BAMAKO, samples were tested from Senegal, Cameroon and western Guinea Conakry as well as from Mali. In southern Mali, where 2Rj polymorphism in SAVANNA populations was very low and most of the 2Rj homozygotes were found in BAMAKO karyotypes, the molecular and cytogenetic methods were almost perfectly congruent. Elsewhere agreement between the methods was much poorer, as the molecular assay frequently misclassified 2Rj heterozygotes as 2R+j standard homozygotes. Molecular karyotyping of 2Rj is robust and accurate on 2R+j standard and 2Rj inverted homozygotes. Therefore, the proposed approach overcomes the lack of a rapid tool for identifying the BAMAKO form across developmental stages and sexes, and opens new perspectives for the study of BAMAKO ecology and behaviour. On the other hand, the method should not be applied for molecular karyotyping of j-carriers within the SAVANNA chromosomal form.

The chromosomal association/dissociation of the chromatin insulator protein Cp190 of Drosophila melanogaster is mediated by the BTB/POZ domain and two acidic regions.

PubMed

Oliver, Daniel; Sheehan, Brian; South, Heather; Akbari, Omar; Pai, Chi-Yun

2010-12-31

Chromatin insulators or boundary elements are a class of functional elements in the eukaryotic genome. They regulate gene transcription by interfering with promoter-enhancer communication. The Cp190 protein of Drosophila melanogaster is essential to the function of at least three-types of chromatin insulator complexes organized by Su(Hw), CTCF and BEAF32. We mapped functional regions of Cp190 in vivo and identified three domains that are essential for the insulator function and for the viability of flies: the BTB/POZ domain, an aspartic acid-rich (D-rich) region and a C-terminal glutamic acid-rich (E-rich) region. Other domains including the centrosomal targeting domain and the zinc fingers are dispensable. The N-terminal CP190BTB-D fragment containing the BTB/POZ domain and the D-rich region is sufficient to mediate association with all three types of insulator complexes. The fragment however is not sufficient for insulator activity or viability. The Cp190 and CP190BTB-D are regulated differently in cells treated with heat-shock. The Cp190 dissociated from chromosomes during heat-shock, indicating that dissociation of Cp190 with chromosomes can be regulated. In contrast, the CP190BTB-D fragment didn't dissociate from chromosomes in the same heat-shocked condition, suggesting that the deleted C-terminal regions have a role in regulating the dissociation of Cp190 with chromosomes. The N-terminal fragment of Cp190 containing the BTB/POZ domain and the D-rich region mediates association of Cp190 with all three types of insulator complexes and that the E-rich region of Cp190 is required for dissociation of Cp190 from chromosomes during heat-shock. The heat-shock-induced dissociation is strong evidence indicating that dissociation of the essential insulator protein Cp190 from chromosomes is regulated. Our results provide a mechanism through which activities of an insulator can be modulated by internal and external cues.

The Norrie disease gene maps to a 150 kb region on chromosome Xp11.3.

PubMed

Sims, K B; Lebo, R V; Benson, G; Shalish, C; Schuback, D; Chen, Z Y; Bruns, G; Craig, I W; Golbus, M S; Breakefield, X O

1992-05-01

Norrie disease is a human X-linked recessive disorder of unknown etiology characterized by congenital blindness, sensory neural deafness and mental retardation. This disease gene was previously linked to the DXS7 (L1.28) locus and the MAO genes in band Xp11.3. We report here fine physical mapping of the obligate region containing the Norrie disease gene (NDP) defined by a recombination and by the smallest submicroscopic chromosomal deletion associated with Norrie disease identified to date. Analysis, using in addition two overlapping YAC clones from this region, allowed orientation of the MAOA and MAOB genes in a 5'-3'-3'-5' configuration. A recombination event between a (GT)n polymorphism in intron 2 of the MAOB gene and the NDP locus, in a family previously reported to have a recombination between DXS7 and NDP, delineates a flanking marker telomeric to this disease gene. An anonymous DNA probe, dc12, present in one of the YACs and in a patient with a submicroscopic deletion which includes MAOA and MAOB but not L1.28, serves as a flanking marker centromeric to the disease gene. An Alu-PCR fragment from the right arm of the MAO YAC (YMAO.AluR) is not deleted in this patient and also delineates the centromeric extent of the obligate disease region. The apparent order of these loci is telomere ... DXS7-MAOA-MAOB-NDP-dc12-YMAO.AluR ... centromere. Together these data define the obligate region containing the NDP gene to a chromosomal segment less than 150 kb.

Recent Sex Chromosome Divergence despite Ancient Dioecy in the Willow Salix viminalis

PubMed Central

Pucholt, Pascal; Wright, Alison E.; Conze, Lei Liu; Mank, Judith E.; Berlin, Sofia

2017-01-01

Abstract Sex chromosomes can evolve when recombination is halted between a pair of chromosomes, and this can lead to degeneration of the sex-limited chromosome. In the early stages of differentiation sex chromosomes are homomorphic, and even though homomorphic sex chromosomes are very common throughout animals and plants, we know little about the evolutionary forces shaping these types of sex chromosomes. We used DNA- and RNA-Seq data from females and males to explore the sex chromosomes in the female heterogametic willow, Salix viminalis, a species with ancient dioecy but with homomorphic sex chromosomes. We detected no major sex differences in read coverage in the sex determination (SD) region, indicating that the W region has not significantly degenerated. However, single nucleotide polymorphism densities in the SD region are higher in females compared with males, indicating very recent recombination suppression, followed by the accumulation of sex-specific single nucleotide polymorphisms. Interestingly, we identified two female-specific scaffolds that likely represent W-chromosome-specific sequence. We show that genes located in the SD region display a mild excess of male-biased expression in sex-specific tissue, and we use allele-specific gene expression analysis to show that this is the result of masculinization of expression on the Z chromosome rather than degeneration of female-expression on the W chromosome. Together, our results demonstrate that insertion of small DNA fragments and accumulation of sex-biased gene expression can occur before the detectable decay of the sex-limited chromosome. PMID:28453634

Genomic copy number analysis of a spectrum of blue nevi identifies recurrent aberrations of entire chromosomal arms in melanoma ex blue nevus.

PubMed

Chan, May P; Andea, Aleodor A; Harms, Paul W; Durham, Alison B; Patel, Rajiv M; Wang, Min; Robichaud, Patrick; Fisher, Gary J; Johnson, Timothy M; Fullen, Douglas R

2016-03-01

Blue nevi may display significant atypia or undergo malignant transformation. Morphologic diagnosis of this spectrum of lesions is notoriously difficult, and molecular tools are increasingly used to improve diagnostic accuracy. We studied copy number aberrations in a cohort of cellular blue nevi, atypical cellular blue nevi, and melanomas ex blue nevi using Affymetrix's OncoScan platform. Cases with sufficient DNA were analyzed for GNAQ, GNA11, and HRAS mutations. Copy number aberrations were detected in 0 of 5 (0%) cellular blue nevi, 3 of 12 (25%) atypical cellular blue nevi, and 6 of 9 (67%) melanomas ex blue nevi. None of the atypical cellular blue nevi displayed more than one aberration, whereas complex aberrations involving four or more regions were seen exclusively in melanomas ex blue nevi. Gains and losses of entire chromosomal arms were identified in four of five melanomas ex blue nevi with copy number aberrations. In particular, gains of 1q, 4p, 6p, and 8q, and losses of 1p and 4q were each found in at least two melanomas. Whole chromosome aberrations were also common, and represented the sole finding in one atypical cellular blue nevus. When seen in melanomas, however, whole chromosome aberrations were invariably accompanied by partial aberrations of other chromosomes. Three melanomas ex blue nevi harbored aberrations, which were absent or negligible in their precursor components, suggesting progression in tumor biology. Gene mutations involving GNAQ and GNA11 were each detected in two of eight melanomas ex blue nevi. In conclusion, copy number aberrations are more common and often complex in melanomas ex blue nevi compared with cellular and atypical cellular blue nevi. Identification of recurrent gains and losses of entire chromosomal arms in melanomas ex blue nevi suggests that development of new probes targeting these regions may improve detection and risk stratification of these lesions.

Fine mapping and positional candidate studies on chromosome 5p13 identify multiple asthma susceptibility loci.

PubMed

Kurz, Thorsten; Hoffjan, Sabine; Hayes, M Geoffrey; Schneider, Dan; Nicolae, Raluca; Heinzmann, Andrea; Jerkic, Sylvija P; Parry, Rod; Cox, Nancy J; Deichmann, Klaus A; Ober, Carole

2006-08-01

Genome-wide linkage scans to identify asthma susceptibility loci have revealed many linked regions, including a broad region on chromosome 5p. To identify a 5p-linked asthma or bronchial hyperresponsiveness (BHR) locus. We performed fine mapping and positional candidate studies of this region in the Hutterites and an outbred case-control sample from Germany by genotyping 89 single nucleotide polymorphisms (SNPs) in 22 genes. SNP and haplotype analyses were performed. Three genes in a distal region (zinc finger RNA binding protein [ZFR], natriuretic peptide receptor C, and a disintegrin and metalloproteinase domain with thrombospondin type 1 motif [ADAMTS12]) were associated with BHR, whereas 4 genes in a proximal region (prolactin receptor, IL-7 receptor [IL7R], leukemia inhibitory factor receptor [LIFR], and prostaglandin E4 receptor [PTGER4]) were associated with asthma symptoms in the Hutterites. Furthermore, nearly the entire original linkage signal in the Hutterites was generated by individuals who had the risk-associated alleles in ZFR3, natriuretic peptide receptor C, ADAMTS12, LIFR, and PTGER4. Variation in ADAMTS12, IL7R, and PTGER4 were also associated with asthma in the outbred Germans, and the frequencies of long-range haplotypes composed of SNPs at ZFR, ADAMTS12, IL7R, LIFR, and PTGER4 were significantly different between both the German and Hutterite cases and controls. There is little linkage disequilbrium between alleles in these 2 regions in either population. These results suggest that a broad region on 5p, separated by >9 Mb, harbors at least 2 and possibly 5 asthma or BHR susceptibility loci. These findings are consistent with the hypothesis that regions providing evidence for linkage in multiple populations may, in fact, house more than 1 susceptibility locus, as appears to be the case for the linked region on 5p. Identifying asthma or BHR genes could lead to novel therapeutic approaches.

Extreme selective sweeps independently targeted the X chromosomes of the great apes

PubMed Central

Nam, Kiwoong; Munch, Kasper; Hobolth, Asger; Dutheil, Julien Yann; Veeramah, Krishna R.; Woerner, August E.; Hammer, Michael F.; Mailund, Thomas; Schierup, Mikkel Heide

2015-01-01

The unique inheritance pattern of the X chromosome exposes it to natural selection in a way that is different from that of the autosomes, potentially resulting in accelerated evolution. We perform a comparative analysis of X chromosome polymorphism in 10 great ape species, including humans. In most species, we identify striking megabase-wide regions, where nucleotide diversity is less than 20% of the chromosomal average. Such regions are found exclusively on the X chromosome. The regions overlap partially among species, suggesting that the underlying targets are partly shared among species. The regions have higher proportions of singleton SNPs, higher levels of population differentiation, and a higher nonsynonymous-to-synonymous substitution ratio than the rest of the X chromosome. We show that the extent to which diversity is reduced is incompatible with direct selection or the action of background selection and soft selective sweeps alone, and therefore, we suggest that very strong selective sweeps have independently targeted these specific regions in several species. The only genomic feature that we can identify as strongly associated with loss of diversity is the location of testis-expressed ampliconic genes, which also have reduced diversity around them. We hypothesize that these genes may be responsible for selective sweeps in the form of meiotic drive caused by an intragenomic conflict in male meiosis. PMID:25941379

Cryptic breakpoint identified by whole-genome mate-pair sequencing in a rare paternally inherited complex chromosomal rearrangement.

PubMed

Aristidou, Constantia; Theodosiou, Athina; Ketoni, Andria; Bak, Mads; Mehrjouy, Mana M; Tommerup, Niels; Sismani, Carolina

2018-01-01

Precise characterization of apparently balanced complex chromosomal rearrangements in non-affected individuals is crucial as they may result in reproductive failure, recurrent miscarriages or affected offspring. We present a family, where the non-affected father and daughter were found, using FISH and karyotyping, to be carriers of a three-way complex chromosomal rearrangement [t(6;7;10)(q16.2;q34;q26.1), de novo in the father]. The family suffered from two stillbirths, one miscarriage, and has a son with severe intellectual disability. In the present study, the family was revisited using whole-genome mate-pair sequencing. Interestingly, whole-genome mate-pair sequencing revealed a cryptic breakpoint on derivative (der) chromosome 6 rendering the rearrangement even more complex. FISH using a chromosome (chr) 6 custom-designed probe and a chr10 control probe confirmed that the interstitial chr6 segment, created by the two chr6 breakpoints, was translocated onto der(10). Breakpoints were successfully validated with Sanger sequencing, and small imbalances as well as microhomology were identified. Finally, the complex chromosomal rearrangement breakpoints disrupted the SIM1 , GRIK2 , CNTNAP2 , and PTPRE genes without causing any phenotype development. In contrast to the majority of maternally transmitted complex chromosomal rearrangement cases, our study investigated a rare case where a complex chromosomal rearrangement, which most probably resulted from a Type IV hexavalent during the pachytene stage of meiosis I, was stably transmitted from a fertile father to his non-affected daughter. Whole-genome mate-pair sequencing proved highly successful in identifying cryptic complexity, which consequently provided further insight into the meiotic segregation of chromosomes and the increased reproductive risk in individuals carrying the specific complex chromosomal rearrangement. We propose that such complex rearrangements should be characterized in detail using a combination

Variability in the heterochromatin regions of the chromosomes and chromosomal anomalies in children with autism: identification of genetic markers of autistic spectrum disorders.

PubMed

Vorsanova, S G; Yurov, I Yu; Demidova, I A; Voinova-Ulas, V Yu; Kravets, V S; Solov'ev, I V; Gorbachevskaya, N L; Yurov, Yu B

2007-07-01

Cytogenetic and molecular cytogenetic analysis of children with autism (90 subjects) and their mothers (18 subjects) is presented. Anomalies and fragility were found in chromosome X in four cases of autism: mos 47,XXX[98]/46, XX[2]; 46,XY,r(22)(p11q13); 46,XY,inv(2)(p11.2q13),16qh-; and 46,Y,fra(X)(q27.3),16qh-. C staining and quantitative fluorescent in situ hybridization (FISH) were used to demonstrate a significant increase in the frequency of variations in the heterochromatin regions of chromosomes in children with autism as compared with a control group (48% and 16% respectively). Pericentric chromosome inversion 9phqh was not characteristic of patients with autism, while variation in heterochromatin regions 1phqh, 9qh+, and 16qh-were found significantly more frequently in children with autism. These data provide the basis for discussing the possible role of the gene position effect in the pathogenesis of autism and the possible search for biological markers of autistic disorders.

Transfer of chromosome 3 fragments suppresses tumorigenicity of an ovarian cancer cell line monoallelic for chromosome 3p.

PubMed

Cody, N A L; Ouellet, V; Manderson, E N; Quinn, M C J; Filali-Mouhim, A; Tellis, P; Zietarska, M; Provencher, D M; Mes-Masson, A-M; Chevrette, M; Tonin, P N

2007-01-25

Multiple chromosome 3p tumor suppressor genes (TSG) have been proposed in the pathogenesis of ovarian cancer based on complex patterns of 3p loss. To attain functional evidence in support of TSGs and identify candidate regions, we applied a chromosome transfer method involving cell fusions of the tumorigenic OV90 human ovarian cancer cell line, monoallelic for 3p and an irradiated mouse cell line containing a human chromosome 3 in order to derive OV90 hybrids containing normal 3p fragments. The resulting hybrids showed complete or incomplete suppression of tumorigenicity in nude mouse xenograft assays, and varied in their ability to form colonies in soft agarose and three-dimensional spheroids in a manner consistent with alteration of their in vivo tumorigenic phenotypes. Expression microarray analysis identified a set of common differentially expressed genes, such as SPARC, DAB2 and VEGF, some of which have been shown implicated in ovarian cancer. Genotyping assays revealed that they harbored normal 3p fragments, some of which overlapped candidate TSG regions (3p25-p26, 3p24 and 3p14-pcen) identified previously in loss of heterozygosity analyses of ovarian cancers. However, only the 3p12-pcen region was acquired in common by all hybrids where expression microarray analysis identified differentially expressed genes. The correlation of 3p12-pcen transfer and tumor suppression with a concerted re-programming of the cellular transcriptome suggest that the putative TSG may have affected key underlying events in ovarian cancer.

4p16.3 microdeletions and microduplications detected by chromosomal microarray analysis: New insights into mechanisms and critical regions.

PubMed

Bi, Weimin; Cheung, Sau-Wai; Breman, Amy M; Bacino, Carlos A

2016-10-01

Deletions in the 4p16.3 region cause Wolf-Hirschhorn syndrome, a well known contiguous microdeletion syndrome with the critical region for common phenotype mapped in WHSCR2. Recently, duplications in 4p16.3 were reported in three patients with developmental delay and dysmorphic features. Through chromosomal microarray analysis, we identified 156 patients with a deletion (n = 109) or duplication (n = 47) in 4p16.3 out of approximately 60,000 patients analyzed by Baylor Miraca Genetics Laboratories. Seventy-five of the postnatally detected deletions encompassed the entire critical region, 32 (43%) of which were associated with other chromosome rearrangements, including six patients (8%) that had a duplication adjacent to the terminal deletion. Our data indicate that Wolf-Hirschhorn syndrome deletions with an adjacent duplication occur at a higher frequency than previously appreciated. Pure deletions (n = 14) or duplications (n = 15) without other copy number changes distal to or inside the WHSCR2 were identified for mapping of critical regions. Our data suggest that deletion of the segment from 0.6 to 0.9 Mb from the terminus of 4p causes a seizure phenotype and duplications of a region distal to the previously defined smallest region of overlap for 4p16.3 microduplication syndrome are associated with neurodevelopmental problems. We detected seven Wolf-Hirschhorn syndrome deletions and one 4p16.3 duplication prenatally; all of the seven are either >8 Mb in size and/or associated with large duplications. In conclusion, our study provides deeper insight into the molecular mechanisms, the critical regions and effective prenatal diagnosis for 4p16.3 deletions/ duplications. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Delineation and physical separation of novel translocation breakpoints on chromosome 1p in two genetically closely associated childhood tumors.

PubMed

Steenman, M J; Zijlstra, N; Kruitbosch, D L; Wiesmeijer, C; Larizza, L; Voûte, P A; Westerveld, A; Mannens, M M

2000-01-01

Sporadic childhood tumors associated with Beckwith-Wiedemann syndrome (BWS) all show abnormalities of the same region on chromosome 11. In addition to chromosome 11, other chromosome regions are affected in some of these tumor types. In this study we analyzed the region on chromosome 1p involved in the etiology of BWS-associated tumors, Wilms tumor, rhabdomyosarcoma, and hepatoblastoma. For this purpose we determined the location of two novel translocation breakpoints in this chromosome region in cells from a Wilms tumor and cells from a rhabdomyosarcoma. We constructed a map of the region and found that both breakpoints are separated by at least 875 kb. We identified a PAC clone which crosses the rhabdomyosarcoma breakpoint and found several exons within this clone. We established that this breakpoint is located proximal to the PAX7 gene and, therefore, identified a new region involved in the etiology of rhabdomyosarcomas. Copyright 2000 S. Karger AG, Basel

Close but Distinct Regions of Human Herpesvirus 8 Latency-Associated Nuclear Antigen 1 Are Responsible for Nuclear Targeting and Binding to Human Mitotic Chromosomes

PubMed Central

Piolot, Tristan; Tramier, Marc; Coppey, Maité; Nicolas, Jean-Claude; Marechal, Vincent

2001-01-01

Human herpesvirus 8 is associated with all forms of Kaposi's sarcoma, AIDS-associated body cavity-based lymphomas, and some forms of multicentric Castleman's disease. Herpesvirus 8, like other gammaherpesviruses, can establish a latent infection in which viral genomes are stably maintained as multiple episomes. The latent nuclear antigen (LANA or LNAI) may play an essential role in the stable maintenance of latent episomes, notably by interacting concomitantly with the viral genomes and the metaphase chromosomes, thus ensuring an efficient transmission of the neoduplicated episomes to the daughter cells. To identify the regions responsible for its nuclear and subnuclear localization in interphase and mitotic cells, LNAI and various truncated forms were fused to a variant of green fluorescent protein. This enabled their localization and chromosome binding activity to be studied by low-light-level fluorescence microscopy in living HeLa cells. The results demonstrate that nuclear localization of LNAI is due to a unique signal, which maps between amino acids 24 and 30. Interestingly, this nuclear localization signal closely resembles those identified in EBNA1 from Epstein-Barr virus and herpesvirus papio. A region encompassing amino acids 5 to 22 was further proved to mediate the specific interaction of LNA1 with chromatin during interphase and the chromosomes during mitosis. The presence of putative phosphorylation sites in the chromosome binding sites of LNA1 and EBNA1 suggests that their activity may be regulated by specific cellular kinases. PMID:11264383

Recent Sex Chromosome Divergence despite Ancient Dioecy in the Willow Salix viminalis.

PubMed

Pucholt, Pascal; Wright, Alison E; Conze, Lei Liu; Mank, Judith E; Berlin, Sofia

2017-08-01

Sex chromosomes can evolve when recombination is halted between a pair of chromosomes, and this can lead to degeneration of the sex-limited chromosome. In the early stages of differentiation sex chromosomes are homomorphic, and even though homomorphic sex chromosomes are very common throughout animals and plants, we know little about the evolutionary forces shaping these types of sex chromosomes. We used DNA- and RNA-Seq data from females and males to explore the sex chromosomes in the female heterogametic willow, Salix viminalis, a species with ancient dioecy but with homomorphic sex chromosomes. We detected no major sex differences in read coverage in the sex determination (SD) region, indicating that the W region has not significantly degenerated. However, single nucleotide polymorphism densities in the SD region are higher in females compared with males, indicating very recent recombination suppression, followed by the accumulation of sex-specific single nucleotide polymorphisms. Interestingly, we identified two female-specific scaffolds that likely represent W-chromosome-specific sequence. We show that genes located in the SD region display a mild excess of male-biased expression in sex-specific tissue, and we use allele-specific gene expression analysis to show that this is the result of masculinization of expression on the Z chromosome rather than degeneration of female-expression on the W chromosome. Together, our results demonstrate that insertion of small DNA fragments and accumulation of sex-biased gene expression can occur before the detectable decay of the sex-limited chromosome. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Detailed dissection of the chromosomal region containing the Ph1 locus in wheat Triticum aestivum: with deletion mutants and expression profiling.

PubMed

Al-Kaff, Nadia; Knight, Emilie; Bertin, Isabelle; Foote, Tracie; Hart, Nicola; Griffiths, Simon; Moore, Graham

2008-04-01

Understanding Ph1, a dominant homoeologous chromosome pairing suppressor locus on the long arm of chromosome 5B in wheat Triticum aestivum L., is the core of the investigation in this article. The Ph1 locus restricts chromosome pairing and recombination at meiosis to true homologues. The importance of wheat as a crop and the need to exploit its wild relatives as donors for economically important traits in wheat breeding programmes is the main drive to uncover the mechanism of the Ph1 locus and regulate its activity. Following the molecular genetic characterization of the Ph1 locus, five additional deletion mutants covering the region have been identified. In addition, more bacterial artificial chromosomes (BACs) were sequenced and analysed to elucidate the complexity of this locus. A semi-quantitative RT-PCR was used to compare the expression profiles of different genes in the 5B region containing the Ph1 locus with their homoeologues on 5A and 5D. PCR products were cloned and sequenced to identify the gene from which they were derived. Deletion mutants and expression profiling of genes in the region containing the Ph1 locus on 5B has further restricted Ph1 to a cluster of cdk-like genes. Bioinformatic analysis of the cdk-like genes revealed their close homology to the checkpoint kinase Cdk2 from humans. Cdk2 is involved in the initiation of replication and is required in early meiosis. Expression profiling has revealed that the cdk-like gene cluster is unique within the region analysed on 5B in that these genes are transcribed. Deletion of the cdk-like locus on 5B results in activation of transcription of functional cdk-like copies on 5A and 5D. Thus the cdk locus on 5B is dominant to those on 5A and 5D in determining the overall activity, which will be dependent on a complex interplay between transcription from non-functional and functional cdk-like genes. The Ph1 locus has been defined to a cdk-like gene cluster related to Cdk2 in humans, a master checkpoint

Fragile Sites of 'Valencia' Sweet Orange (Citrus sinensis) Chromosomes Are Related with Active 45s rDNA.

PubMed

Lan, Hong; Chen, Chun-Li; Miao, Yin; Yu, Chang-Xiu; Guo, Wen-Wu; Xu, Qiang; Deng, Xiu-Xin

2016-01-01

Citrus sinensis chromosomes present a morphological differentiation of bands after staining by the fluorochromes CMA and DAPI, but there is still little information on its chromosomal characteristics. In this study, the chromosomes in 'Valencia' C. sinensis were analyzed by fluorescence in situ hybridization (FISH) using telomere DNA and the 45S rDNA gene as probes combining CMA/DAPI staining, which showed that there were two fragile sites in sweet orange chromosomes co-localizing at distended 45S rDNA regions, one proximally locating on B-type chromosome and the other subterminally locating on D-type chromosome. While the chromosomal CMA banding and 45S rDNA FISH mapping in the doubled haploid line of 'Valencia' C. sinensis indicated six 45S rDNA regions, four were identified as fragile sites as doubled comparing its parental line, which confirmed the cytological heterozygosity and chromosomal heteromorphisms in sweet orange. Furthermore, Ag-NOR identified two distended 45S rDNA regions to be active nucleolar organizing regions (NORs) in diploid 'Valencia' C. sinensis. The occurrence of quadrivalent in meiosis of pollen mother cells (PMCs) in 'Valencia' sweet orange further confirmed it was a chromosomal reciprocal translocation line. We speculated this chromosome translocation was probably related to fragile sites. Our data provide insights into the chromosomal characteristics of the fragile sites in 'Valencia' sweet orange and are expected to facilitate the further investigation of the possible functions of fragile sites.

A Rare De novo Complex Chromosomal Rearrangement (CCR) Involving Four Chromosomes in An Oligo-asthenosperm Infertile Man

PubMed Central

Asia, Saba; Vaziri Nasab, Hamed; Sabbaghian, Marjan; Kalantari, Hamid; Zari Moradi, Shabnam; Gourabi, Hamid; Mohseni Meybodi, Anahita

2014-01-01

Complex chromosomal rearrangements (CCRs) are rare events involving more than two chromosomes and over two breakpoints. They are usually associated with infertility or sub fertility in male carriers. Here we report a novel case of a CCR in a 30-year-old oligoasthenosperm man with a history of varicocelectomy, normal testes size and normal endocrinology profile referred for chromosome analysis to the Genetics unit of Royan Reproductive Biomedicine Research Center. Chromosomal analysis was performed using peripheral blood lymphocyte cultures and analyzed by GTG banding. Additional tests such as C-banding and multicolor fluorescence in situ hybridization (FISH) procedure for each of the involved chromosomes were performed to determine the patterns of the segregations. Y chromosome microdeletions in the azoospermia factor (AZF) region were analyzed with multiplex polymerase chain reaction. To identify the history and origin of this CCR, all the family members were analyzed. No micro deletion in Y chromosome was detected. The same de novo reciprocal exchange was also found in his monozygous twin brother. The other siblings and parents were normal. CCRs are associated with male infertility as a result of spermatogenic disruption due to complex meiotic configurations and the production of chromosomally abnormal sperms. These chromosomal rearrangements might have an influence on decreasing the number of sperms. PMID:24611143

Molecular Characterization of the Pericentric Inversion That Causes Differences Between Chimpanzee Chromosome 19 and Human Chromosome 17

PubMed Central

Kehrer-Sawatzki, Hildegard; Schreiner, Bettina; Tänzer, Simone; Platzer, Matthias; Müller, Stefan; Hameister, Horst

2002-01-01

A comparison of the human genome with that of the chimpanzee is an attractive approach to attempts to understand the specificity of a certain phenotype's development. The two karyotypes differ by one chromosome fusion, nine pericentric inversions, and various additions of heterochromatin to chromosomal telomeres. Only the fusion, which gave rise to human chromosome 2, has been characterized at the sequence level. During the present study, we investigated the pericentric inversion by which chimpanzee chromosome 19 differs from human chromosome 17. Fluorescence in situ hybridization was used to identify breakpoint-spanning bacterial artificial chromosomes (BACs) and plasmid artificial chromosomes (PACs). By sequencing the junction fragments, we localized breakpoints in intergenic regions rich in repetitive elements. Our findings suggest that repeat-mediated nonhomologous recombination has facilitated inversion formation. No addition or deletion of any sequence element was detected at the breakpoints or in the surrounding sequences. Next to the break, at a distance of 10.2–39.1 kb, the following genes were found: NGFR and NXPH3 (on human chromosome 17q21.3) and GUC2D and ALOX15B (on human chromosome 17p13). The inversion affects neither the genomic structure nor the gene-activity state with regard to replication timing of these genes. PMID:12094327

Constitutional chromoanasynthesis: description of a rare chromosomal event in a patient.

PubMed

Plaisancié, Julie; Kleinfinger, Pascale; Cances, Claude; Bazin, Anne; Julia, Sophie; Trost, Detlef; Lohmann, Laurence; Vigouroux, Adeline

2014-10-01

Structural alterations in chromosomes are a frequent cause of cancers and congenital diseases. Recently, the phenomenon of chromosome crisis, consisting of a set of tens to hundreds of clustered genomic rearrangements, localized in one or a few chromosomes, was described in cancer cells under the term chromothripsis. Better knowledge and recognition of this catastrophic chromosome event has brought to light two distinct entities, chromothripsis and chromoanasynthesis. The complexity of these rearrangements and the original descriptions in tumor cells initially led to the thought that it was an acquired anomaly. In fact, a few patients have been reported with constitutional chromothripsis or chromoanasynthesis. Using microarray we identified a very complex chromosomal rearrangement in a patient who had a cytogenetically visible rearrangement of chromosome 18. The rearrangement contained more than 15 breakpoints localized on a single chromosome. Our patient displayed intellectual disability, behavioral troubles and craniofacial dysmorphism. Interestingly, the succession of duplications and triplications identified in our patient was not clustered on a single chromosomal region but spread over the entire chromosome 18. In the light of this new spectrum of chromosomal rearrangements, this report outlines the main features of these catastrophic events and discusses the underlying mechanism of the complex chromosomal rearrangement identified in our patient, which is strongly evocative of a chromoanasynthesis. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Replication of alpha-satellite DNA arrays in endogenous human centromeric regions and in human artificial chromosome

PubMed Central

Erliandri, Indri; Fu, Haiqing; Nakano, Megumi; Kim, Jung-Hyun; Miga, Karen H.; Liskovykh, Mikhail; Earnshaw, William C.; Masumoto, Hiroshi; Kouprina, Natalay; Aladjem, Mirit I.; Larionov, Vladimir

2014-01-01

In human chromosomes, centromeric regions comprise megabase-size arrays of 171 bp alpha-satellite DNA monomers. The large distances spanned by these arrays preclude their replication from external sites and imply that the repetitive monomers contain replication origins. However, replication within these arrays has not previously been profiled and the role of alpha-satellite DNA in initiation of DNA replication has not yet been demonstrated. Here, replication of alpha-satellite DNA in endogenous human centromeric regions and in de novo formed Human Artificial Chromosome (HAC) was analyzed. We showed that alpha-satellite monomers could function as origins of DNA replication and that replication of alphoid arrays organized into centrochromatin occurred earlier than those organized into heterochromatin. The distribution of inter-origin distances within centromeric alphoid arrays was comparable to the distribution of inter-origin distances on randomly selected non-centromeric chromosomal regions. Depletion of CENP-B, a kinetochore protein that binds directly to a 17 bp CENP-B box motif common to alpha-satellite DNA, resulted in enrichment of alpha-satellite sequences for proteins of the ORC complex, suggesting that CENP-B may have a role in regulating the replication of centromeric regions. Mapping of replication initiation sites in the HAC revealed that replication preferentially initiated in transcriptionally active regions. PMID:25228468

Anchoring genome sequence to chromosomes of the central bearded dragon (Pogona vitticeps) enables reconstruction of ancestral squamate macrochromosomes and identifies sequence content of the Z chromosome.

PubMed

Deakin, Janine E; Edwards, Melanie J; Patel, Hardip; O'Meally, Denis; Lian, Jinmin; Stenhouse, Rachael; Ryan, Sam; Livernois, Alexandra M; Azad, Bhumika; Holleley, Clare E; Li, Qiye; Georges, Arthur

2016-06-10

Squamates (lizards and snakes) are a speciose lineage of reptiles displaying considerable karyotypic diversity, particularly among lizards. Understanding the evolution of this diversity requires comparison of genome organisation between species. Although the genomes of several squamate species have now been sequenced, only the green anole lizard has any sequence anchored to chromosomes. There is only limited gene mapping data available for five other squamates. This makes it difficult to reconstruct the events that have led to extant squamate karyotypic diversity. The purpose of this study was to anchor the recently sequenced central bearded dragon (Pogona vitticeps) genome to chromosomes to trace the evolution of squamate chromosomes. Assigning sequence to sex chromosomes was of particular interest for identifying candidate sex determining genes. By using two different approaches to map conserved blocks of genes, we were able to anchor approximately 42 % of the dragon genome sequence to chromosomes. We constructed detailed comparative maps between dragon, anole and chicken genomes, and where possible, made broader comparisons across Squamata using cytogenetic mapping information for five other species. We show that squamate macrochromosomes are relatively well conserved between species, supporting findings from previous molecular cytogenetic studies. Macrochromosome diversity between members of the Toxicofera clade has been generated by intrachromosomal, and a small number of interchromosomal, rearrangements. We reconstructed the ancestral squamate macrochromosomes by drawing upon comparative cytogenetic mapping data from seven squamate species and propose the events leading to the arrangements observed in representative species. In addition, we assigned over 8 Mbp of sequence containing 219 genes to the Z chromosome, providing a list of genes to begin testing as candidate sex determining genes. Anchoring of the dragon genome has provided substantial insight into

Characterisation of the subtelomeric regions of Giardia lamblia genome isolate WBC6.

PubMed

Prabhu, Anjali; Morrison, Hilary G; Martinez, Charles R; Adam, Rodney D

2007-04-01

Giardia trophozoites are polyploid and have five chromosomes. The chromosome homologues demonstrate considerable size heterogeneity due to variation in the subtelomeric regions. We used clones from the genome project with telomeric sequence at one end to identify six subtelomeric regions in addition to previously identified subtelomeric regions, to study the telomeric arrangement of the chromosomes. The subtelomeric regions included two retroposons, one retroposon pseudogene, and two vsp genes, in addition to the previously identified subtelomeric regions that include ribosomal DNA repeats. The presence of vsp genes in a subtelomeric region suggests that telomeric rearrangements may contribute to the generation of vsp diversity. These studies of the subtelomeric regions of Giardia may contribute to our understanding of the factors that maintain stability, while allowing diversity in chromosome structure.

Fragile Sites of ‘Valencia’ Sweet Orange (Citrus sinensis) Chromosomes Are Related with Active 45s rDNA

PubMed Central

Lan, Hong; Chen, Chun-Li; Miao, Yin; Yu, Chang-Xiu; Guo, Wen-Wu; Xu, Qiang; Deng, Xiu-Xin

2016-01-01

Citrus sinensis chromosomes present a morphological differentiation of bands after staining by the fluorochromes CMA and DAPI, but there is still little information on its chromosomal characteristics. In this study, the chromosomes in ‘Valencia’ C. sinensis were analyzed by fluorescence in situ hybridization (FISH) using telomere DNA and the 45S rDNA gene as probes combining CMA/DAPI staining, which showed that there were two fragile sites in sweet orange chromosomes co-localizing at distended 45S rDNA regions, one proximally locating on B-type chromosome and the other subterminally locating on D-type chromosome. While the chromosomal CMA banding and 45S rDNA FISH mapping in the doubled haploid line of ‘Valencia’ C. sinensis indicated six 45S rDNA regions, four were identified as fragile sites as doubled comparing its parental line, which confirmed the cytological heterozygosity and chromosomal heteromorphisms in sweet orange. Furthermore, Ag-NOR identified two distended 45S rDNA regions to be active nucleolar organizing regions (NORs) in diploid ‘Valencia’ C. sinensis. The occurrence of quadrivalent in meiosis of pollen mother cells (PMCs) in ‘Valencia’ sweet orange further confirmed it was a chromosomal reciprocal translocation line. We speculated this chromosome translocation was probably related to fragile sites. Our data provide insights into the chromosomal characteristics of the fragile sites in ‘Valencia’ sweet orange and are expected to facilitate the further investigation of the possible functions of fragile sites. PMID:26977938

Genetic mapping of a locus for multiple ephiphyseal dysplasia (EDM2) to a region of chromosome 1 containing a type IX collagen gene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Briggs, M.D.; Choi, HiChang; Warman, M.L.

1994-10-01

Multiple epiphyseal dysplasia (MED) is a dominantly inherited chondrodysplasia characterized by mild short stature and early-onset osteoarthrosis. Some forms of MED clinically resemble another chondrodysplasia phenotype, the mild form of pseudoachondroplasia (PSACH). On the basis of their clinical similarities as well as similar ultra-structural and biochemical features in cartilage from some patients, it has been proposed that MED and PSACH belong to a single bone-dysplasia family. Recently, both mild and severe PSACH as well as a form of MED have been linked to the same interval on chromosome 19, suggesting that they may be allelic disorders. Linkage studies with themore » chromosome 19 markers were carried out in a large family with MED and excluded the previously identified interval. Using this family, we have identified a MED locus on the short arm of chromosome 1, in a region containing the gene (COL9A2) that encodes the {alpha}2 chain of type IX collagen, a structural component of the cartilage extracellular matrix. 39 refs., 3 figs., 3 tabs.« less

A selective sweep of >8 Mb on chromosome 26 in the Boxer genome.

PubMed

Quilez, Javier; Short, Andrea D; Martínez, Verónica; Kennedy, Lorna J; Ollier, William; Sanchez, Armand; Altet, Laura; Francino, Olga

2011-07-01

Modern dog breeds display traits that are either breed-specific or shared by a few breeds as a result of genetic bottlenecks during the breed creation process and artificial selection for breed standards. Selective sweeps in the genome result from strong selection and can be detected as a reduction or elimination of polymorphism in a given region of the genome. Extended regions of homozygosity, indicative of selective sweeps, were identified in a genome-wide scan dataset of 25 Boxers from the United Kingdom genotyped at ~20,000 single-nucleotide polymorphisms (SNPs). These regions were further examined in a second dataset of Boxers collected from a different geographical location and genotyped using higher density SNP arrays (~170,000 SNPs). A selective sweep previously associated with canine brachycephaly was detected on chromosome 1. A novel selective sweep of over 8 Mb was observed on chromosome 26 in Boxer and for a shorter region in English and French bulldogs. It was absent in 171 samples from eight other dog breeds and 7 Iberian wolf samples. A region of extended increased heterozygosity on chromosome 9 overlapped with a previously reported copy number variant (CNV) which was polymorphic in multiple dog breeds. A selective sweep of more than 8 Mb on chromosome 26 was identified in the Boxer genome. This sweep is likely caused by strong artificial selection for a trait of interest and could have inadvertently led to undesired health implications for this breed. Furthermore, we provide supporting evidence for two previously described regions: a selective sweep on chromosome 1 associated with canine brachycephaly and a CNV on chromosome 9 polymorphic in multiple dog breeds.

A family of long intergenic non-coding RNA genes in human chromosomal region 22q11.2 carry a DNA translocation breakpoint/AT-rich sequence

PubMed Central

2018-01-01

FAM230C, a long intergenic non-coding RNA (lincRNA) gene in human chromosome 13 (chr13) is a member of lincRNA genes termed family with sequence similarity 230. An analysis using bioinformatics search tools and alignment programs was undertaken to determine properties of FAM230C and its related genes. Results reveal that the DNA translocation element, the Translocation Breakpoint Type A (TBTA) sequence, which consists of satellite DNA, Alu elements, and AT-rich sequences is embedded in the FAM230C gene. Eight lincRNA genes related to FAM230C also carry the TBTA sequences. These genes were formed from a large segment of the 3’ half of the FAM230C sequence duplicated in chr22, and are specifically in regions of low copy repeats (LCR22)s, in or close to the 22q.11.2 region. 22q11.2 is a chromosomal segment that undergoes a high rate of DNA translocation and is prone to genetic deletions. FAM230C-related genes present in other chromosomes do not carry the TBTA motif and were formed from the 5’ half region of the FAM230C sequence. These findings identify a high specificity in lincRNA gene formation by gene sequence duplication in different chromosomes. PMID:29668722

Evidence for positive selection of taurine genes within a QTL region on chromosome X associated with testicular size in Australian Brahman cattle

PubMed Central

2014-01-01

Background Previous genome-wide association studies have identified significant regions of the X chromosome associated with reproductive traits in two Bos indicus-influenced breeds: Brahman cattle and Tropical Composites. Two QTL regions on this chromosome were identified in both breeds as strongly associated with scrotal circumference measurements, a reproductive trait previously shown to be useful for selection of young bulls. Scrotal circumference is genetically correlated with early age at puberty in both male and female offspring. These QTL were located at positions 69–77 and 81–92 Mb respectively, large areas each to which a significant number of potential candidate genes were mapped. Results To further characterise these regions, a bioinformatic approach was undertaken to identify novel non-synonymous SNP within the QTL regions of interest in Brahman cattle. After SNP discovery, we used conventional molecular assay technologies to perform studies of two candidate genes in both breeds. Non-synonymous SNP mapped to Testis-expressed gene 11 (Tex11) were associated (P < 0.001) with scrotal circumference in both breeds, and associations with percentage of normal sperm cells were also observed (P < 0.05). Evidence for recent selection was found as Tex11 SNP form a haplotype segment of Bos taurus origin that is retained within Brahman and Tropical Composite cattle with greatest reproductive potential. Conclusions Association of non-synonymous SNP presented here are a first step to functional genetic studies. Bovine species may serve as a model for studying the role of Tex11 in male fertility, warranting further in-depth molecular characterisation. PMID:24410912

Flagellar region 3b supports strong expression of integrated DNA and the highest chromosomal integration efficiency of the Escherichia coli flagellar regions.

PubMed

Juhas, Mario; Ajioka, James W

2015-07-01

The Gram-negative bacterium Escherichia coli is routinely used as the chassis for a variety of biotechnology and synthetic biology applications. Identification and analysis of reliable chromosomal integration and expression target loci is crucial for E. coli engineering. Chromosomal loci differ significantly in their ability to support integration and expression of the integrated genetic circuits. In this study, we investigate E. coli K12 MG1655 flagellar regions 2 and 3b. Integration of the genetic circuit into seven and nine highly conserved genes of the flagellar regions 2 (motA, motB, flhD, flhE, cheW, cheY and cheZ) and 3b (fliE, F, G, J, K, L, M, P, R), respectively, showed significant variation in their ability to support chromosomal integration and expression of the integrated genetic circuit. While not reducing the growth of the engineered strains, the integrations into all 16 target sites led to the loss of motility. In addition to high expression, the flagellar region 3b supports the highest efficiency of integration of all E. coli K12 MG1655 flagellar regions and is therefore potentially the most suitable for the integration of synthetic genetic circuits. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Long range chromosome organization in Escherichia coli: The position of the replication origin defines the non-structured regions and the Right and Left macrodomains

PubMed Central

2017-01-01

The Escherichia coli chromosome is organized into four macrodomains (Ori, Ter, Right and Left) and two non-structured regions. This organization influences the segregation of sister chromatids, the mobility of chromosomal DNA, and the cellular localization of the chromosome. The organization of the Ter and Ori macrodomains relies on two specific systems, MatP/matS for the Ter domain and MaoP/maoS for the Ori domain, respectively. Here by constructing strains with chromosome rearrangements to reshuffle the distribution of chromosomal segments, we reveal that the difference between the non-structured regions and the Right and Left lateral macrodomains relies on their position on the chromosome. A change in the genetic location of oriC generated either by an inversion within the Ori macrodomain or by the insertion of a second oriC modifies the position of Right and Left macrodomains, as the chromosome region the closest to oriC are always non-structured while the regions further away behave as macrodomain regardless of their DNA sequence. Using fluorescent microscopy we estimated that loci belonging to a non-structured region are significantly closer to the Ori MD than loci belonging to a lateral MD. Altogether, our results suggest that the origin of replication plays a prominent role in chromosome organization in E. coli, as it determines structuring and localization of macrodomains in growing cell. PMID:28486476

Structural maintenance of chromosome complexes differentially compact mitotic chromosomes according to genomic context

PubMed Central

Schalbetter, S. A.; Goloborodko, A.; Fudenberg, G.; Belton, J.-M.; Miles, C.; Yu, M.; Dekker, J.; Mirny, L.; Baxter, J.

2017-01-01

Structural Maintenance of Chromosomes (SMC) protein complexes are key determinants of chromosome conformation. Using Hi-C and polymer modeling, we study how cohesin and condensin, two deeply conserved SMC complexes, organize chromosomes in the budding yeast Saccharomyces cerevisiae. The canonical role of cohesin is to co-align sister chromatids whilst condensin generally compacts mitotic chromosomes. We find strikingly different roles for the two complexes in budding yeast mitosis. First, cohesin is responsible for compacting mitotic chromosome arms, independently of sister chromatid cohesion. Polymer simulations demonstrate this role can be fully accounted for through cis-looping of chromatin. Second, condensin is generally dispensable for compaction along chromosome arms. Instead it plays a targeted role compacting the rDNA proximal regions and promoting resolution of peri-centromeric regions. Our results argue that the conserved mechanism of SMC complexes is to form chromatin loops and that distinct SMC-dependent looping activities are selectively deployed to appropriately compact chromosomes. PMID:28825700

A novel primary immunodeficiency with specific natural-killer cell deficiency maps to the centromeric region of chromosome 8.

PubMed

Eidenschenk, Celine; Dunne, Jean; Jouanguy, Emmanuelle; Fourlinnie, Claire; Gineau, Laure; Bacq, Delphine; McMahon, Corrina; Smith, Owen; Casanova, Jean-Laurent; Abel, Laurent; Feighery, Conleth

2006-04-01

We describe four children with a novel primary immunodeficiency consisting of specific natural-killer (NK) cell deficiency and susceptibility to viral diseases. One child developed an Epstein-Barr virus-driven lymphoproliferative disorder; two others developed severe respiratory illnesses of probable viral etiology. The four patients are related and belong to a large inbred kindred of Irish nomadic descent, which suggests autosomal recessive inheritance of this defect. A genomewide scan identified a single 12-Mb region on chromosome 8p11.23-q11.21 that was linked to this immunodeficiency (maximum LOD score 4.51). The mapping of the disease-causing genomic region paves the way for the identification of a novel pathway governing NK cell differentiation in humans.

Assembling the Setaria italica L. Beauv. genome into nine chromosomes and insights into regions affecting growth and drought tolerance

PubMed Central

Tsai, Kevin J.; Lu, Mei-Yeh Jade; Yang, Kai-Jung; Li, Mengyun; Teng, Yuchuan; Chen, Shihmay; Ku, Maurice S. B.; Li, Wen-Hsiung

2016-01-01

The diploid C4 plant foxtail millet (Setaria italica L. Beauv.) is an important crop in many parts of Africa and Asia for the vast consumption of its grain and ability to grow in harsh environments, but remains understudied in terms of complete genomic architecture. To date, there have been only two genome assembly and annotation efforts with neither assembly reaching over 86% of the estimated genome size. We have combined de novo assembly with custom reference-guided improvements on a popular cultivar of foxtail millet and have achieved a genome assembly of 477 Mbp in length, which represents over 97% of the estimated 490 Mbp. The assembly anchors over 98% of the predicted genes to the nine assembled nuclear chromosomes and contains more functional annotation gene models than previous assemblies. Our annotation has identified a large number of unique gene ontology terms related to metabolic activities, a region of chromosome 9 with several growth factor proteins, and regions syntenic with pearl millet or maize genomic regions that have been previously shown to affect growth. The new assembly and annotation for this important species can be used for detailed investigation and future innovations in growth for millet and other grains. PMID:27734962

Assembling the Setaria italica L. Beauv. genome into nine chromosomes and insights into regions affecting growth and drought tolerance.

PubMed

Tsai, Kevin J; Lu, Mei-Yeh Jade; Yang, Kai-Jung; Li, Mengyun; Teng, Yuchuan; Chen, Shihmay; Ku, Maurice S B; Li, Wen-Hsiung

2016-10-13

The diploid C 4 plant foxtail millet (Setaria italica L. Beauv.) is an important crop in many parts of Africa and Asia for the vast consumption of its grain and ability to grow in harsh environments, but remains understudied in terms of complete genomic architecture. To date, there have been only two genome assembly and annotation efforts with neither assembly reaching over 86% of the estimated genome size. We have combined de novo assembly with custom reference-guided improvements on a popular cultivar of foxtail millet and have achieved a genome assembly of 477 Mbp in length, which represents over 97% of the estimated 490 Mbp. The assembly anchors over 98% of the predicted genes to the nine assembled nuclear chromosomes and contains more functional annotation gene models than previous assemblies. Our annotation has identified a large number of unique gene ontology terms related to metabolic activities, a region of chromosome 9 with several growth factor proteins, and regions syntenic with pearl millet or maize genomic regions that have been previously shown to affect growth. The new assembly and annotation for this important species can be used for detailed investigation and future innovations in growth for millet and other grains.

DOP-PCR based painting of rye chromosomes in a wheat background.

PubMed

Deng, Chuanliang; Bai, Lili; Li, Shufen; Zhang, Yingxin; Li, Xiang; Chen, Yuhong; Wang, Richard R-C; Han, Fangpu; Hu, Zanmin

2014-09-01

To determine the appropriateness of chromosome painting for identifying genomic elements in rye, we microdissected the 1R and 1RS chromosomes from rye (Secale cereale L. var. King II) and wheat-rye addition line 1RS, respectively. Degenerate oligonucleotide primed - polymerase chain reaction (DOP-PCR) amplification of 1R and 1RS products from dissected chromosomes were used as probes to hybridize to metaphase chromosomes of rye, wheat-rye addition lines 1R and 1RS, translocation line 1RS.1BL, and allohexaploid triticale. The results showed that (i) the hybridization signal distribution patterns on rye chromosomes using 1R-derived DOP-PCR products as the probe were similar to those using 1RS-derived DOP-PCR products as the probe; (ii) 1R and (or) 1RS could not be distinguished from other rye chromosomes solely by the hybridization patterns using 1R- and (or) 1RS-derived DOP-PCR products as the probe; (iii) rye chromosomes and (or) rye chromosome fragments could be clearly identified in wheat-rye hybrids using either 1R- or 1RS-derived DOP-PCR products as the probe and could be more accurate in the nontelomeric region than using genomic in situ hybridization (GISH). Our results suggested that 1R- and (or) 1RS-derived DOP-PCR products contain many repetitive DNA sequences, are similar on different rye chromosomes, are R-genome specific, and can be used to identify rye chromosomes and chromosome fragments in wheat-rye hybrids. Our research widens the application range of chromosome painting in plants.

Monoamine oxidase deficiency in males with an X chromosome deletion.

PubMed

Sims, K B; de la Chapelle, A; Norio, R; Sankila, E M; Hsu, Y P; Rinehart, W B; Corey, T J; Ozelius, L; Powell, J F; Bruns, G

1989-01-01

Mapping of the human MAOA gene to chromosomal region Xp21-p11 prompted our study of two affected males in a family previously reported to have Norrie disease resulting from a submicroscopic deletion in this chromosomal region. In this investigation we demonstrate in these cousins deletion of the MAOA gene, undetectable levels of MAO-A and MAO-B activities in their fibroblasts and platelets, respectively, loss of mRNA for MAO-A in fibroblasts, and substantial alterations in urinary catecholamine metabolites. The present study documents that a marked deficiency of MAO activity is compatible with life and that genes for MAO-A and MAO-B are near each other in this Xp chromosomal region. Some of the clinical features of these MAO deletion patients may help to identify X-linked MAO deficiency diseases in humans.

Minimum prevalence of chromosome 22q11 deletions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, D.I.; Cross, I.E.; Burn, J.

1994-09-01

Submicroscopic deletions from within chromosome 22q11 are associated with DiGeorge (DGS), velocardiofacial (VCFS) and conotruncal anomaly syndromes and isolated congenital heart defects. In 1993 our pediatric cardiologists clinically referred all children in whom a chromosome 22q11 deletion was suspected for fluorescent in situ hybridization studies using probes from the DGS critical region. 10 affected individuals have been identified to date from the children born in 1993 in the Northern Region served exclusively by our center. A further case, the subsequent pregnancy in one of these families was affected and terminated on the basis of a major heart malformation. In themore » years 1988-92, for which we have complete ascertainment, there were 1009 heart defects among 191,700 births (mean 202 per annum). Thus we estimate that chromosome 22q11 deletions were the cause of at least 5% of congenital heart disease. As not all children with chromosome 22q11 deletions have a heart defect, this gives an estimated minimum prevalence of 1/4000 live births.« less

[High-resolution GTG-banding and nucleolar organizer regions of chromosomes of two vole species: Microtus rossiaemeridonionalis and M. transcaspicus (Rodentia, Arvicolidae)].

PubMed

Mazurok, N A; Rubtsova, N V; Isaenko, A A; Nesterova, T B; Meĭer, M N; Zakiian, S M

1998-08-01

With the use of the GTG-banding of prometaphase chromosomes, 503 and 402 segments were revealed in haploid chromosome sets of voles Microtus rossiaemeridionalis and M. transcaspicus, respectively. Based on a detailed study of chromosomes at different condensation levels, idiograms of M. rossiaemeridionalis and M. transcaspicus chromosomes were constructed. Sequential Ag-staining and GTG-banding allowed nucleolar organizer regions (NORs) to be localized in 16 and 11 chromosome pairs of M. rossiaemeridionalis and M. transcaspicus, respectively.

Pasture names with Romance and Slavic roots facilitate dissection of Y chromosome variation in an exclusively German-speaking alpine region.

PubMed

Niederstätter, Harald; Rampl, Gerhard; Erhart, Daniel; Pitterl, Florian; Oberacher, Herbert; Neuhuber, Franz; Hausner, Isolde; Gassner, Christoph; Schennach, Harald; Berger, Burkhard; Parson, Walther

2012-01-01

The small alpine district of East Tyrol (Austria) has an exceptional demographic history. It was contemporaneously inhabited by members of the Romance, the Slavic and the Germanic language groups for centuries. Since the Late Middle Ages, however, the population of the principally agrarian-oriented area is solely Germanic speaking. Historic facts about East Tyrol's colonization are rare, but spatial density-distribution analysis based on the etymology of place-names has facilitated accurate spatial mapping of the various language groups' former settlement regions. To test for present-day Y chromosome population substructure, molecular genetic data were compared to the information attained by the linguistic analysis of pasture names. The linguistic data were used for subdividing East Tyrol into two regions of former Romance (A) and Slavic (B) settlement. Samples from 270 East Tyrolean men were genotyped for 17 Y-chromosomal microsatellites (Y-STRs) and 27 single nucleotide polymorphisms (Y-SNPs). Analysis of the probands' surnames revealed no evidence for spatial genetic structuring. Also, spatial autocorrelation analysis did not indicate significant correlation between genetic (Y-STR haplotypes) and geographic distance. Haplogroup R-M17 chromosomes, however, were absent in region A, but constituted one of the most frequent haplogroups in region B. The R-M343 (R1b) clade showed a marked and complementary frequency distribution pattern in these two regions. To further test East Tyrol's modern Y-chromosomal landscape for geographic patterning attributable to the early history of settlement in this alpine area, principal coordinates analysis was performed. The Y-STR haplotypes from region A clearly clustered with those of Romance reference populations and the samples from region B matched best with Germanic speaking reference populations. The combined use of onomastic and molecular genetic data revealed and mapped the marked structuring of the distribution of Y

Pasture Names with Romance and Slavic Roots Facilitate Dissection of Y Chromosome Variation in an Exclusively German-Speaking Alpine Region

PubMed Central

Niederstätter, Harald; Rampl, Gerhard; Erhart, Daniel; Pitterl, Florian; Oberacher, Herbert; Neuhuber, Franz; Hausner, Isolde; Gassner, Christoph; Schennach, Harald; Berger, Burkhard; Parson, Walther

2012-01-01

The small alpine district of East Tyrol (Austria) has an exceptional demographic history. It was contemporaneously inhabited by members of the Romance, the Slavic and the Germanic language groups for centuries. Since the Late Middle Ages, however, the population of the principally agrarian-oriented area is solely Germanic speaking. Historic facts about East Tyrol's colonization are rare, but spatial density-distribution analysis based on the etymology of place-names has facilitated accurate spatial mapping of the various language groups' former settlement regions. To test for present-day Y chromosome population substructure, molecular genetic data were compared to the information attained by the linguistic analysis of pasture names. The linguistic data were used for subdividing East Tyrol into two regions of former Romance (A) and Slavic (B) settlement. Samples from 270 East Tyrolean men were genotyped for 17 Y-chromosomal microsatellites (Y-STRs) and 27 single nucleotide polymorphisms (Y-SNPs). Analysis of the probands' surnames revealed no evidence for spatial genetic structuring. Also, spatial autocorrelation analysis did not indicate significant correlation between genetic (Y-STR haplotypes) and geographic distance. Haplogroup R-M17 chromosomes, however, were absent in region A, but constituted one of the most frequent haplogroups in region B. The R-M343 (R1b) clade showed a marked and complementary frequency distribution pattern in these two regions. To further test East Tyrol's modern Y-chromosomal landscape for geographic patterning attributable to the early history of settlement in this alpine area, principal coordinates analysis was performed. The Y-STR haplotypes from region A clearly clustered with those of Romance reference populations and the samples from region B matched best with Germanic speaking reference populations. The combined use of onomastic and molecular genetic data revealed and mapped the marked structuring of the distribution of Y

Non-coding-regulatory regions of human brain genes delineated by bacterial artificial chromosome knock-in mice.

PubMed

Schmouth, Jean-François; Castellarin, Mauro; Laprise, Stéphanie; Banks, Kathleen G; Bonaguro, Russell J; McInerny, Simone C; Borretta, Lisa; Amirabbasi, Mahsa; Korecki, Andrea J; Portales-Casamar, Elodie; Wilson, Gary; Dreolini, Lisa; Jones, Steven J M; Wasserman, Wyeth W; Goldowitz, Daniel; Holt, Robert A; Simpson, Elizabeth M

2013-10-14

The next big challenge in human genetics is understanding the 98% of the genome that comprises non-coding DNA. Hidden in this DNA are sequences critical for gene regulation, and new experimental strategies are needed to understand the functional role of gene-regulation sequences in health and disease. In this study, we build upon our HuGX ('high-throughput human genes on the X chromosome') strategy to expand our understanding of human gene regulation in vivo. In all, ten human genes known to express in therapeutically important brain regions were chosen for study. For eight of these genes, human bacterial artificial chromosome clones were identified, retrofitted with a reporter, knocked single-copy into the Hprt locus in mouse embryonic stem cells, and mouse strains derived. Five of these human genes expressed in mouse, and all expressed in the adult brain region for which they were chosen. This defined the boundaries of the genomic DNA sufficient for brain expression, and refined our knowledge regarding the complexity of gene regulation. We also characterized for the first time the expression of human MAOA and NR2F2, two genes for which the mouse homologs have been extensively studied in the central nervous system (CNS), and AMOTL1 and NOV, for which roles in CNS have been unclear. We have demonstrated the use of the HuGX strategy to functionally delineate non-coding-regulatory regions of therapeutically important human brain genes. Our results also show that a careful investigation, using publicly available resources and bioinformatics, can lead to accurate predictions of gene expression.

Differential repetitive DNA composition in the centromeric region of chromosomes of Amazonian lizard species in the family Teiidae

PubMed Central

Carvalho, Natalia D. M.; Carmo, Edson; Neves, Rogerio O.; Schneider, Carlos Henrique; Gross, Maria Claudia

2016-01-01

Abstract Differences in heterochromatin distribution patterns and its composition were observed in Amazonian teiid species. Studies have shown repetitive DNA harbors heterochromatic blocks which are located in centromeric and telomeric regions in Ameiva ameiva (Linnaeus, 1758), Kentropyx calcarata (Spix, 1825), Kentropyx pelviceps (Cope, 1868), and Tupinambis teguixin (Linnaeus, 1758). In Cnemidophorus sp.1, repetitive DNA has multiple signals along all chromosomes. The aim of this study was to characterize moderately and highly repetitive DNA sequences by Cot1-DNA from Ameiva ameiva and Cnemidophorus sp.1 genomes through cloning and DNA sequencing, as well as mapping them chromosomally to better understand its organization and genome dynamics. The results of sequencing of DNA libraries obtained by Cot1-DNA showed that different microsatellites, transposons, retrotransposons, and some gene families also comprise the fraction of repetitive DNA in the teiid species. FISH using Cot1-DNA probes isolated from both Ameiva ameiva and Cnemidophorus sp.1 showed these sequences mainly located in heterochromatic centromeric, and telomeric regions in Ameiva ameiva, Kentropyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin chromosomes, indicating they play structural and functional roles in the genome of these species. In Cnemidophorus sp.1, Cot1-DNA probe isolated from Ameiva ameiva had multiple interstitial signals on chromosomes, whereas mapping of Cot1-DNA isolated from the Ameiva ameiva and Cnemidophorus sp.1 highlighted centromeric regions of some chromosomes. Thus, the data obtained showed that many repetitive DNA classes are part of the genome of Ameiva ameiva, Cnemidophorus sp.1, Kentroyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin, and these sequences are shared among the analyzed teiid species, but they were not always allocated at the same chromosome position. PMID:27551343

Chromosomes, conflict, and epigenetics: chromosomal speciation revisited.

PubMed

Brown, Judith D; O'Neill, Rachel J

2010-01-01

Since Darwin first noted that the process of speciation was indeed the "mystery of mysteries," scientists have tried to develop testable models for the development of reproductive incompatibilities-the first step in the formation of a new species. Early theorists proposed that chromosome rearrangements were implicated in the process of reproductive isolation; however, the chromosomal speciation model has recently been questioned. In addition, recent data from hybrid model systems indicates that simple epistatic interactions, the Dobzhansky-Muller incompatibilities, are more complex. In fact, incompatibilities are quite broad, including interactions among heterochromatin, small RNAs, and distinct, epigenetically defined genomic regions such as the centromere. In this review, we will examine both classical and current models of chromosomal speciation and describe the "evolving" theory of genetic conflict, epigenetics, and chromosomal speciation.

Genetic linkage studies in familial partial epilepsy: Exclusion of the human chromosome regions syntenic to the El-1 mouse locus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopes-Cendes, I.; Mulley, J.C.; Andermann, E.

1994-09-01

Recently, six families with a familial form of partial epilepsy were described. All pedigrees showed autosomal dominant inheritance with incomplete penetrance. Affected individuals present with predominantly nocturnal seizures with frontal lobe semiology. In 1959, a genetic mouse model for partial epilepsy, the El mouse, was reported. In the El mouse, a major seizure susceptibility gene, El-1, segregates in an autosomal dominant fashion and has been localized to a region distal to the centromere of mouse chromosome 9. Comparative genetic maps between man and mouse have been used for prediction of localization of several human disease genes. Because the region ofmore » mouse chromosome 9 that is the most likely to contain the El-1 locus is syntenic to regions on human chromosomes 3q21-p22, 3q21-q23.3, 6q12 and 15q24, we adopted the candidate gene approach as an initial linkage strategy. Twenty-two polymorphic microsatellite markers covering these regions were used for genotyping individuals in the three larger families ascertained, two of which are Australian and one French-Canadian. Negative two-point lod scores were obtained separately for each family. The analysis of all three families combined significantly excludes the candidate regions on chromosomes 3, 6 and 15.« less

Partial trisomy of chromosome 22 resulting from a supernumerary marker chromosome 22 in a child with features of cat eye syndrome.

PubMed

Bélien, Valérie; Gérard-Blanluet, Marion; Serero, Stéphane; Le Dû, Nathalie; Baumann, Clarisse; Jacquemont, Marie-Line; Dupont, Céline; Krabchi, Kada; Drunat, Séverine; Elbez, Annie; Janaud, Jean-Claude; Benzacken, Brigitte; Verloes, Alain; Tabet, Anne-Claude; Aboura, Azzedine

2008-07-15

Small supernumerary marker chromosomes are present in about 0.05% of the human population. In approximately 28% of persons with these markers (excluding the approximately 60% derived from one of the acrocentric chromosomes), an abnormal phenotype is observed. We report on a 3-month-old girl with intrauterine growth retardation, craniofacial features, hypotonia, partial coloboma of iris and total anomalous pulmonary venous return. Cytogenetic analysis showed the presence of a supernumerary marker chromosome, identified by fluorescence in situ hybridization as part of chromosome 22, and conferring a proximal partial trisomy 22q22.21, not encompassing the DiGeorge critical region (RP11-154H4 + , TBX1-). This observation adds new information relevant to cat eye syndrome and partial trisomy of 22q. 2008 Wiley-Liss, Inc.

A small XY chromosomal region explains sex determination in wild dioecious V. vinifera and the reversal to hermaphroditism in domesticated grapevines.

PubMed

Picq, Sandrine; Santoni, Sylvain; Lacombe, Thierry; Latreille, Muriel; Weber, Audrey; Ardisson, Morgane; Ivorra, Sarah; Maghradze, David; Arroyo-Garcia, Rosa; Chatelet, Philippe; This, Patrice; Terral, Jean-Frédéric; Bacilieri, Roberto

2014-09-03

In Vitis vinifera L., domestication induced a dramatic change in flower morphology: the wild sylvestris subspecies is dioecious while hermaphroditism is largely predominant in the domesticated subsp. V. v. vinifera. The characterisation of polymorphisms in genes underlying the sex-determining chromosomal region may help clarify the history of domestication in grapevine and the evolution of sex chromosomes in plants. In the genus Vitis, sex determination is putatively controlled by one major locus with three alleles, male M, hermaphrodite H and female F, with an allelic dominance M > H > F. Previous genetic studies located the sex locus on chromosome 2. We used DNA polymorphisms of geographically diverse V. vinifera genotypes to confirm the position of this locus, to characterise the genetic diversity and traces of selection in candidate genes, and to explore the origin of hermaphroditism. In V. v. sylvestris, a sex-determining region of 154.8 kb, also present in other Vitis species, spans less than 1% of chromosome 2. It displays haplotype diversity, linkage disequilibrium and differentiation that typically correspond to a small XY sex-determining region with XY males and XX females. In male alleles, traces of purifying selection were found for a trehalose phosphatase, an exostosin and a WRKY transcription factor, with strikingly low polymorphism levels between distant geographic regions. Both diversity and network analysis revealed that H alleles are more closely related to M than to F alleles. Hermaphrodite alleles appear to derive from male alleles of wild grapevines, with successive recombination events allowing import of diversity from the X into the Y chromosomal region and slowing down the expansion of the region into a full heteromorphic chromosome. Our data are consistent with multiple domestication events and show traces of introgression from other Asian Vitis species into the cultivated grapevine gene pool.

Engineered chromosome-based genetic mapping establishes a 3.7 Mb critical genomic region for Down syndrome-associated heart defects in mice.

PubMed

Liu, Chunhong; Morishima, Masae; Jiang, Xiaoling; Yu, Tao; Meng, Kai; Ray, Debjit; Pao, Annie; Ye, Ping; Parmacek, Michael S; Yu, Y Eugene

2014-06-01

Trisomy 21 (Down syndrome, DS) is the most common human genetic anomaly associated with heart defects. Based on evolutionary conservation, DS-associated heart defects have been modeled in mice. By generating and analyzing mouse mutants carrying different genomic rearrangements in human chromosome 21 (Hsa21) syntenic regions, we found the triplication of the Tiam1-Kcnj6 region on mouse chromosome 16 (Mmu16) resulted in DS-related cardiovascular abnormalities. In this study, we developed two tandem duplications spanning the Tiam1-Kcnj6 genomic region on Mmu16 using recombinase-mediated genome engineering, Dp(16)3Yey and Dp(16)4Yey, spanning the 2.1 Mb Tiam1-Il10rb and 3.7 Mb Ifnar1-Kcnj6 regions, respectively. We found that Dp(16)4Yey/+, but not Dp(16)3Yey/+, led to heart defects, suggesting the triplication of the Ifnar1-Kcnj6 region is sufficient to cause DS-associated heart defects. Our transcriptional analysis of Dp(16)4Yey/+ embryos showed that the Hsa21 gene orthologs located within the duplicated interval were expressed at the elevated levels, reflecting the consequences of the gene dosage alterations. Therefore, we have identified a 3.7 Mb genomic region, the smallest critical genomic region, for DS-associated heart defects, and our results should set the stage for the final step to establish the identities of the causal gene(s), whose elevated expression(s) directly underlie this major DS phenotype.

Genome-wide association and regional heritability mapping to identify loci underlying variation in nematode resistance and body weight in Scottish Blackface lambs.

PubMed

Riggio, V; Matika, O; Pong-Wong, R; Stear, M J; Bishop, S C

2013-05-01

The genetic architecture underlying nematode resistance and body weight in Blackface lambs was evaluated comparing genome-wide association (GWA) and regional heritability mapping (RHM) approaches. The traits analysed were faecal egg count (FEC) and immunoglobulin A activity against third-stage larvae from Teladorsagia circumcincta, as indicators of nematode resistance, and body weight in a population of 752 Scottish Blackface lambs, genotyped with the 50k single-nucleotide polymorphism (SNP) chip. FEC for both Nematodirus and Strongyles nematodes (excluding Nematodirus), as well as body weight were collected at approximately 16, 20 and 24 weeks of age. In addition, a weighted average animal effect was estimated for both FEC and body weight traits. After quality control, 44 388 SNPs were available for the GWA analysis and 42 841 for the RHM, which utilises only mapped SNPs. The same fixed effects were used in both analyses: sex, year, management group, litter size and age of dam, with day of birth as covariate. Some genomic regions of interest for both nematode resistance and body weight traits were identified, using both GWA and RHM approaches. For both methods, strong evidence for association was found on chromosome 14 for Nematodirus average animal effect, chromosome 6 for Strongyles FEC at 16 weeks and chromosome 6 for body weight at 16 weeks. Across the entire data set, RHM identified more regions reaching the suggestive level than GWA, suggesting that RHM is capable of capturing some of the variation not detected by GWA analyses.

Cloning a balanced t(9;11)(p24;q23.1) chromosomal translocation breakpoint segregating with bipolar affective disorder in a small pedigree

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duggan, D.J.; Baysal, B.E.; Gollin, S.M.

A small multigenerational pedigree was previously identified in which a balanced 9;11 chromosomal translocation was cosegregating with bipolar affective disorder. We hypothesize that genes or gene regulatory sequences disrupted by the translocation are contributing to bipolar affective disorder in a dominant fashion. The general strategy involves (1) using somatic cell hybrids containing the derivative 9 or 11 chromosomes to identify the closest chromosome 9 and 11 flanking markers, (2) using the nearest markers as PCR and hybridization probes to isolate both normal DNA (YAC) and patient DNA (cosmid) adjacent to and incorporating the translocation breakpoint, and (3) identifying expressed sequencesmore » in the genomic DNA that may be disrupted by the translocation. From a fusion of the translocation patient cell line and a recipient hamster cell line, somatic cell hybrids were isolated which contain either the human derivative 9 or derivative 11 chromosome. Using PCR-based STS assays with these hybrids, the location of the translocation breakpoint was localized to an estimated 500 kb region at chromosome 11 band q23.1 and a 1 cM region in 9 band p24 (more telomeric than originally reported). From a large set of CEPH and Roswell Park yeast artificial chromosomes (YACs), six chromosome 11 YACs spanning the 11q23.1 breakpoint have now been identified. A combination of pulsed field gel eletrophoresis and YAC mapping has narrowed the chromosome 11 region to less than 430 kb. Current efforts are focused on generating new chromosome 11 probes within the flanking markers, mapping these probes back to the der(9) and der(11) containing hybrids and the chromosome 11 YAC mapping panel. As the region is physically narrowed, we will identify candidate genes whose expression may be altered by this t(9:11) translocation.« less

Electron microscope mapping of the pericentric and intercalary heterochromatic regions of the polytene chromosomes of the mutant Suppressor of underreplication in Drosophila melanogaster.

PubMed

Semeshin, F; Belyaeva, S; Zhimulev, F

2001-12-01

Breaks and ectopic contacts in the heterochromatic regions of Drosophila melanogaster polytene chromosomes are the manifestations of the cytological effects of DNA underreplication. Their appearance makes these regions difficult to map. The Su(UR)ES gene, which controls the phenomenon, has been described recently. Mutation of this locus gives rise to new blocks of material in the pericentric heterochromatic regions and causes the disappearance of breaks and ectopic contacts in the intercalary heterochromatic regions, thereby making the banding pattern distinct and providing better opportunities for mapping of the heterochromatic regions in polytene chromosomes. Here, we present the results of an electron microscope study of the heterochromatic regions. In the wild-type salivary glands, the pericentric regions correspond to the beta-heterochromatin and do not show the banding pattern. The most conspicuous cytological effect of the Su(UR)ES mutation is the formation of a large banded chromosome fragment comprising at least 25 bands at the site where the 3L and 3R proximal arms connect. In the other pericentric regions, 20CF, 40BF and 41BC, 15, 12 and 9 new bands were revealed, respectively. A large block of densely packed material appears in the most proximal part of the fourth chromosome. An electron microscope analysis of 26 polytene chromosome regions showing the characteristic features of intercalary heterochromatin was also performed. Suppression of DNA underreplication in the mutant transforms the bands with weak spots into large single bands.

Characterization of chromosomal architecture in Arabidopsis by chromosome conformation capture

PubMed Central

2013-01-01

Background The packaging of long chromatin fibers in the nucleus poses a major challenge, as it must fulfill both physical and functional requirements. Until recently, insights into the chromosomal architecture of plants were mainly provided by cytogenetic studies. Complementary to these analyses, chromosome conformation capture technologies promise to refine and improve our view on chromosomal architecture and to provide a more generalized description of nuclear organization. Results Employing circular chromosome conformation capture, this study describes chromosomal architecture in Arabidopsis nuclei from a genome-wide perspective. Surprisingly, the linear organization of chromosomes is reflected in the genome-wide interactome. In addition, we study the interplay of the interactome and epigenetic marks and report that the heterochromatic knob on the short arm of chromosome 4 maintains a pericentromere-like interaction profile and interactome despite its euchromatic surrounding. Conclusion Despite the extreme condensation that is necessary to pack the chromosomes into the nucleus, the Arabidopsis genome appears to be packed in a predictive manner, according to the following criteria: heterochromatin and euchromatin represent two distinct interactomes; interactions between chromosomes correlate with the linear position on the chromosome arm; and distal chromosome regions have a higher potential to interact with other chromosomes. PMID:24267747

A Novel Primary Immunodeficiency with Specific Natural-Killer Cell Deficiency Maps to the Centromeric Region of Chromosome 8

PubMed Central

Eidenschenk, Céline; Dunne, Jean; Jouanguy, Emmanuelle; Fourlinnie, Claire; Gineau, Laure; Bacq, Delphine; McMahon, Corrina; Smith, Owen; Casanova, Jean-Laurent; Abel, Laurent; Feighery, Conleth

2006-01-01

We describe four children with a novel primary immunodeficiency consisting of specific natural-killer (NK) cell deficiency and susceptibility to viral diseases. One child developed an Epstein-Barr virus–driven lymphoproliferative disorder; two others developed severe respiratory illnesses of probable viral etiology. The four patients are related and belong to a large inbred kindred of Irish nomadic descent, which suggests autosomal recessive inheritance of this defect. A genomewide scan identified a single 12-Mb region on chromosome 8p11.23-q11.21 that was linked to this immunodeficiency (maximum LOD score 4.51). The mapping of the disease-causing genomic region paves the way for the identification of a novel pathway governing NK cell differentiation in humans. PMID:16532402

Differential repetitive DNA composition in the centromeric region of chromosomes of Amazonian lizard species in the family Teiidae.

PubMed

Carvalho, Natalia D M; Carmo, Edson; Neves, Rogerio O; Schneider, Carlos Henrique; Gross, Maria Claudia

2016-01-01

Differences in heterochromatin distribution patterns and its composition were observed in Amazonian teiid species. Studies have shown repetitive DNA harbors heterochromatic blocks which are located in centromeric and telomeric regions in Ameiva ameiva (Linnaeus, 1758), Kentropyx calcarata (Spix, 1825), Kentropyx pelviceps (Cope, 1868), and Tupinambis teguixin (Linnaeus, 1758). In Cnemidophorus sp.1, repetitive DNA has multiple signals along all chromosomes. The aim of this study was to characterize moderately and highly repetitive DNA sequences by C ot1-DNA from Ameiva ameiva and Cnemidophorus sp.1 genomes through cloning and DNA sequencing, as well as mapping them chromosomally to better understand its organization and genome dynamics. The results of sequencing of DNA libraries obtained by C ot1-DNA showed that different microsatellites, transposons, retrotransposons, and some gene families also comprise the fraction of repetitive DNA in the teiid species. FISH using C ot1-DNA probes isolated from both Ameiva ameiva and Cnemidophorus sp.1 showed these sequences mainly located in heterochromatic centromeric, and telomeric regions in Ameiva ameiva, Kentropyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin chromosomes, indicating they play structural and functional roles in the genome of these species. In Cnemidophorus sp.1, C ot1-DNA probe isolated from Ameiva ameiva had multiple interstitial signals on chromosomes, whereas mapping of C ot1-DNA isolated from the Ameiva ameiva and Cnemidophorus sp.1 highlighted centromeric regions of some chromosomes. Thus, the data obtained showed that many repetitive DNA classes are part of the genome of Ameiva ameiva, Cnemidophorus sp.1, Kentroyx calcarata, Kentropyx pelviceps, and Tupinambis teguixin, and these sequences are shared among the analyzed teiid species, but they were not always allocated at the same chromosome position.

Chromosome dynamics in meiotic prophase I in plants.

PubMed

Ronceret, A; Pawlowski, W P

2010-07-01

Early stages of meiotic prophase are characterized by complex and dramatic chromosome dynamics. Chromosome behavior during this period is associated with several critical meiotic processes that take place at the molecular level, such as recombination and homologous chromosome recognition and pairing. Studies to characterize specific patterns of chromosome dynamics and to identify their exact roles in the progression of meiotic prophase are only just beginning in plants. These studies are facilitated by advances in imaging technology in the recent years, including development of ultra-resolution three-dimensional and live microscopy methods. Studies conducted so far indicate that different chromosome regions exhibit different dynamics patterns in early prophase. In many species telomeres cluster at the nuclear envelope at the beginning of zygotene forming the telomere bouquet. The bouquet has been traditionally thought to facilitate chromosome pairing by bringing chromosome ends into close proximity, but recent studies suggest that its main role may rather be facilitating rapid movements of chromosomes during zygotene. In some species, including wheat and Arabidopsis, there is evidence that centromeres form pairs (couple) before the onset of pairing of chromosome arms. While significant advances have been achieved in elucidating the patterns of chromosome behavior in meiotic prophase I, factors controlling chromosome dynamics are still largely unknown and require further studies. Copyright 2010 S. Karger AG, Basel.

Chromosomal Flexibility

ERIC Educational Resources Information Center

Journal of College Science Teaching, 2005

2005-01-01

Scientists have shown that a genetic element on one chromosome may direct gene activity on another. Howard Hughes Medical Institute (HHMI) researchers report that a multitasking master-control region appears to over-see both a set of its own genes and a related gene on a nearby chromosome. The findings reinforce the growing importance of location…

Mapping of the chromosome 1p36 region surrounding the Charcot-Marie-Tooth disease type 2A locus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denton, P.; Gere, S.; Wolpert, C.

1994-09-01

Charcot-Marie-Tooth (CMT) disease is the most common inherited peripheral neuropathy. Although CMT2 is clinically indistinguishable from CMT1, the two forms can be differentiated by pathological and neurophysiological methods. We have established one locus, CMT2A on chromosome 1p36, and have established genetic heterogeneity. This locus maps to the region of the deletions associated with neuroblastoma. We have now identified an additional 11 CMT2 families. Three families are linked to chromosome 1p36 while six families are excluded from this region. Another six families are currently under analysis and collection. To date the CMT2A families represent one third of those CMT2 families examined.more » We have established a microdissection library of the 1p36 region which is currently being characterized for microsatellite repeats and STSs using standard hybridization techniques and a modified degenerate primer method. In addition, new markers (D1S253, D1S450, D1S489, D1S503, GATA27E04, and GATA4H04) placed in this region are being mapped using critical recombinants in the CEPH reference pedigrees. Fluorescent in situ hybridization (FISH) has been used to confirm mapping. A YAC contig is being assembled from the CEPH megabase library using STSs to isolate key YACs which are extended by vectorette end clone and Alu-PCR. These findings suggest that the CMT2 phenotype is secondary to at least two different genes and demonstrates further heterogeneity in the CMT phenotype.« less

A fresh look at the male-specific region of the human Y chromosome.

PubMed

Jangravi, Zohreh; Alikhani, Mehdi; Arefnezhad, Babak; Sharifi Tabar, Mehdi; Taleahmad, Sara; Karamzadeh, Razieh; Jadaliha, Mahdieh; Mousavi, Seyed Ahmad; Ahmadi Rastegar, Diba; Parsamatin, Pouria; Vakilian, Haghighat; Mirshahvaladi, Shahab; Sabbaghian, Marjan; Mohseni Meybodi, Anahita; Mirzaei, Mehdi; Shahhoseini, Maryam; Ebrahimi, Marzieh; Piryaei, Abbas; Moosavi-Movahedi, Ali Akbar; Haynes, Paul A; Goodchild, Ann K; Nasr-Esfahani, Mohammad Hossein; Jabbari, Esmaiel; Baharvand, Hossein; Sedighi Gilani, Mohammad Ali; Gourabi, Hamid; Salekdeh, Ghasem Hosseini

2013-01-04

The Chromosome-centric Human Proteome Project (C-HPP) aims to systematically map the entire human proteome with the intent to enhance our understanding of human biology at the cellular level. This project attempts simultaneously to establish a sound basis for the development of diagnostic, prognostic, therapeutic, and preventive medical applications. In Iran, current efforts focus on mapping the proteome of the human Y chromosome. The male-specific region of the Y chromosome (MSY) is unique in many aspects and comprises 95% of the chromosome's length. The MSY continually retains its haploid state and is full of repeated sequences. It is responsible for important biological roles such as sex determination and male fertility. Here, we present the most recent update of MSY protein-encoding genes and their association with various traits and diseases including sex determination and reversal, spermatogenesis and male infertility, cancers such as prostate cancers, sex-specific effects on the brain and behavior, and graft-versus-host disease. We also present information available from RNA sequencing, protein-protein interaction, post-translational modification of MSY protein-coding genes and their implications in biological systems. An overview of Human Y chromosome Proteome Project is presented and a systematic approach is suggested to ensure that at least one of each predicted protein-coding gene's major representative proteins will be characterized in the context of its major anatomical sites of expression, its abundance, and its functional relevance in a biological and/or medical context. There are many technical and biological issues that will need to be overcome in order to accomplish the full scale mapping.

Microdissection and chromosome painting of the alien chromosome in an addition line of wheat-Thinopyrum intermedium

USDA-ARS?s Scientific Manuscript database

The chromosome painting is an efficient tool for chromosome research. However, plant chromosome painting is relatively underdeveloped. In this study, chromosome painting was developed and used to identify alien chromosomes in TAi-27, a wheat-Thinopyrum intermedium addition line, and chromosomes of...

Chromosome heteromorphism quantified by high-resolution bivariate flow karyotyping.

PubMed Central

Trask, B; van den Engh, G; Mayall, B; Gray, J W

1989-01-01

Maternal and paternal homologues of many chromosome types can be differentiated on the basis of their peak position in Hoechst 33258 versus chromomycin A3 bivariate flow karyotypes. We demonstrate here the magnitude of DNA content differences among normal chromosomes of the same type. Significant peak-position differences between homologues were observed for an average of four chromosome types in each of the karyotypes of 98 different individuals. The frequency of individuals with differences in homologue peak positions varied among chromosome types: e.g., chromosome 15, 61%; chromosome 3, 4%. Flow karyotypes of 33 unrelated individuals were compared to determine the range of peak position among normal chromosomes. Chromosomes Y, 21, 22, 15, 16, 13, 14, and 19 were most heteromorphic, and chromosomes 2-8 and X were least heteromorphic. The largest chromosome 21 was 45% larger than the smallest 21 chromosome observed. The base composition of the variable regions differed among chromosome types. DNA contents of chromosome variants determined from flow karyotypes were closely correlated to measurements of DNA content made of gallocyanin chrome alum-stained metaphase chromosomes on slides. Fluorescence in situ hybridization with chromosome-specific repetitive sequences indicated that variability in their copy number is partly responsible for peak-position variability in some chromosomes. Heteromorphic chromosomes are identified for which parental flow karyotype information will be essential if de novo rearrangements resulting in small DNA content changes are to be detected with flow karyotyping. Images Figure 5 PMID:2479266

Ancestral chromosomal blocks are triplicated in Brassiceae species with varying chromosome number and genome size.

PubMed

Lysak, Martin A; Cheung, Kwok; Kitschke, Michaela; Bures, Petr

2007-10-01

The paleopolyploid character of genomes of the economically important genus Brassica and closely related species (tribe Brassiceae) is still fairly controversial. Here, we report on the comparative painting analysis of block F of the crucifer Ancestral Karyotype (AK; n = 8), consisting of 24 conserved genomic blocks, in 10 species traditionally treated as members of the tribe Brassiceae. Three homeologous copies of block F were identified per haploid chromosome complement in Brassiceae species with 2n = 14, 18, 20, 32, and 36. In high-polyploid (n >or= 30) species Crambe maritima (2n = 60), Crambe cordifolia (2n = 120), and Vella pseudocytisus (2n = 68), six, 12, and six copies of the analyzed block have been revealed, respectively. Homeologous regions resembled the ancestral structure of block F within the AK or were altered by inversions and/or translocations. In two species of the subtribe Zillineae, two of the three homeologous regions were combined via a reciprocal translocation onto one chromosome. Altogether, these findings provide compelling evidence of an ancient hexaploidization event and corresponding whole-genome triplication shared by the tribe Brassiceae. No direct relationship between chromosome number and genome size variation (1.2-2.5 pg/2C) has been found in Brassiceae species with 2n = 14 to 36. Only two homeologous copies of block F suggest a whole-genome duplication but not the triplication event in Orychophragmus violaceus (2n = 24), and confirm a phylogenetic position of this species outside the tribe Brassiceae. Chromosome duplication detected in Orychophragmus as well as chromosome rearrangements shared by Zillineae species demonstrate the usefulness of comparative cytogenetics for elucidation of phylogenetic relationships.

Partial hexasomy of chromosome 15.

PubMed

Huang, Bing; Bartley, James

2003-09-01

Marker chromosomes originating from chromosome 15, often referred to as inv dup(15), is the most common marker chromosome found in humans. The large marker 15 that contains the Prader-Willi syndrome (PWS)/Angelman syndrome (AS) chromosome region is usually associated with an abnormal phenotype of moderate to severe mental retardation, seizures, poor motor coordination, behavioral problems, and mild dysmorphic features. We report here an infant boy with two copies of the large inv dup(15). A 10-day-old infant was found to have infantile spasms, microcephaly, hypotonia, and lethargy. Lymphocyte chromosome analysis revealed a 48,XY, +2mar karyotype. Fluorescence in situ hybridization with probes rRNA, D15Z4, D15S11, and GABRB3 demonstrated that both markers were chromosome 15 in origin and contained the Prader-Willi/Angelman syndrome chromosome region. Therefore, this patient is hexasomic for the PWS/AS region. The phenotype of this patient does not appear to be significantly more severe than patients with one copy of the large inv dup(15) at birth, however, follow-up evaluation of the patient at 21 months of age shows that this patient has frequent and severe seizure activity, severe bilateral hearing loss, and cortical blindness. Copyright 2003 Wiley-Liss, Inc.

Chromosome arm-specific BAC end sequences permit comparative analysis of homoeologous chromosomes and genomes of polyploid wheat

PubMed Central

2012-01-01

Background Bread wheat, one of the world’s staple food crops, has the largest, highly repetitive and polyploid genome among the cereal crops. The wheat genome holds the key to crop genetic improvement against challenges such as climate change, environmental degradation, and water scarcity. To unravel the complex wheat genome, the International Wheat Genome Sequencing Consortium (IWGSC) is pursuing a chromosome- and chromosome arm-based approach to physical mapping and sequencing. Here we report on the use of a BAC library made from flow-sorted telosomic chromosome 3A short arm (t3AS) for marker development and analysis of sequence composition and comparative evolution of homoeologous genomes of hexaploid wheat. Results The end-sequencing of 9,984 random BACs from a chromosome arm 3AS-specific library (TaaCsp3AShA) generated 11,014,359 bp of high quality sequence from 17,591 BAC-ends with an average length of 626 bp. The sequence represents 3.2% of t3AS with an average DNA sequence read every 19 kb. Overall, 79% of the sequence consisted of repetitive elements, 1.38% as coding regions (estimated 2,850 genes) and another 19% of unknown origin. Comparative sequence analysis suggested that 70-77% of the genes present in both 3A and 3B were syntenic with model species. Among the transposable elements, gypsy/sabrina (12.4%) was the most abundant repeat and was significantly more frequent in 3A compared to homoeologous chromosome 3B. Twenty novel repetitive sequences were also identified using de novo repeat identification. BESs were screened to identify simple sequence repeats (SSR) and transposable element junctions. A total of 1,057 SSRs were identified with a density of one per 10.4 kb, and 7,928 junctions between transposable elements (TE) and other sequences were identified with a density of one per 1.39 kb. With the objective of enhancing the marker density of chromosome 3AS, oligonucleotide primers were successfully designed from 758 SSRs and 695

Imputation and subset-based association analysis across different cancer types identifies multiple independent risk loci in the TERT-CLPTM1L region on chromosome 5p15.33

PubMed Central

Wang, Zhaoming; Zhu, Bin; Zhang, Mingfeng; Parikh, Hemang; Jia, Jinping; Chung, Charles C.; Sampson, Joshua N.; Hoskins, Jason W.; Hutchinson, Amy; Burdette, Laurie; Ibrahim, Abdisamad; Hautman, Christopher; Raj, Preethi S.; Abnet, Christian C.; Adjei, Andrew A.; Ahlbom, Anders; Albanes, Demetrius; Allen, Naomi E.; Ambrosone, Christine B.; Aldrich, Melinda; Amiano, Pilar; Amos, Christopher; Andersson, Ulrika; Andriole, Gerald; Andrulis, Irene L.; Arici, Cecilia; Arslan, Alan A.; Austin, Melissa A.; Baris, Dalsu; Barkauskas, Donald A.; Bassig, Bryan A.; Beane Freeman, Laura E.; Berg, Christine D.; Berndt, Sonja I.; Bertazzi, Pier Alberto; Biritwum, Richard B.; Black, Amanda; Blot, William; Boeing, Heiner; Boffetta, Paolo; Bolton, Kelly; Boutron-Ruault, Marie-Christine; Bracci, Paige M.; Brennan, Paul; Brinton, Louise A.; Brotzman, Michelle; Bueno-de-Mesquita, H. Bas; Buring, Julie E.; Butler, Mary Ann; Cai, Qiuyin; Cancel-Tassin, Geraldine; Canzian, Federico; Cao, Guangwen; Caporaso, Neil E.; Carrato, Alfredo; Carreon, Tania; Carta, Angela; Chang, Gee-Chen; Chang, I-Shou; Chang-Claude, Jenny; Che, Xu; Chen, Chien-Jen; Chen, Chih-Yi; Chen, Chung-Hsing; Chen, Constance; Chen, Kuan-Yu; Chen, Yuh-Min; Chokkalingam, Anand P.; Chu, Lisa W.; Clavel-Chapelon, Francoise; Colditz, Graham A.; Colt, Joanne S.; Conti, David; Cook, Michael B.; Cortessis, Victoria K.; Crawford, E. David; Cussenot, Olivier; Davis, Faith G.; De Vivo, Immaculata; Deng, Xiang; Ding, Ti; Dinney, Colin P.; Di Stefano, Anna Luisa; Diver, W. Ryan; Duell, Eric J.; Elena, Joanne W.; Fan, Jin-Hu; Feigelson, Heather Spencer; Feychting, Maria; Figueroa, Jonine D.; Flanagan, Adrienne M.; Fraumeni, Joseph F.; Freedman, Neal D.; Fridley, Brooke L.; Fuchs, Charles S.; Gago-Dominguez, Manuela; Gallinger, Steven; Gao, Yu-Tang; Gapstur, Susan M.; Garcia-Closas, Montserrat; Garcia-Closas, Reina; Gastier-Foster, Julie M.; Gaziano, J. Michael; Gerhard, Daniela S.; Giffen, Carol A.; Giles, Graham G.; Gillanders, Elizabeth M.; Giovannucci, Edward L.; Goggins, Michael; Gokgoz, Nalan; Goldstein, Alisa M.; Gonzalez, Carlos; Gorlick, Richard; Greene, Mark H.; Gross, Myron; Grossman, H. Barton; Grubb, Robert; Gu, Jian; Guan, Peng; Haiman, Christopher A.; Hallmans, Goran; Hankinson, Susan E.; Harris, Curtis C.; Hartge, Patricia; Hattinger, Claudia; Hayes, Richard B.; He, Qincheng; Helman, Lee; Henderson, Brian E.; Henriksson, Roger; Hoffman-Bolton, Judith; Hohensee, Chancellor; Holly, Elizabeth A.; Hong, Yun-Chul; Hoover, Robert N.; Hosgood, H. Dean; Hsiao, Chin-Fu; Hsing, Ann W.; Hsiung, Chao Agnes; Hu, Nan; Hu, Wei; Hu, Zhibin; Huang, Ming-Shyan; Hunter, David J.; Inskip, Peter D.; Ito, Hidemi; Jacobs, Eric J.; Jacobs, Kevin B.; Jenab, Mazda; Ji, Bu-Tian; Johansen, Christoffer; Johansson, Mattias; Johnson, Alison; Kaaks, Rudolf; Kamat, Ashish M.; Kamineni, Aruna; Karagas, Margaret; Khanna, Chand; Khaw, Kay-Tee; Kim, Christopher; Kim, In-Sam; Kim, Jin Hee; Kim, Yeul Hong; Kim, Young-Chul; Kim, Young Tae; Kang, Chang Hyun; Jung, Yoo Jin; Kitahara, Cari M.; Klein, Alison P.; Klein, Robert; Kogevinas, Manolis; Koh, Woon-Puay; Kohno, Takashi; Kolonel, Laurence N.; Kooperberg, Charles; Kratz, Christian P.; Krogh, Vittorio; Kunitoh, Hideo; Kurtz, Robert C.; Kurucu, Nilgun; Lan, Qing; Lathrop, Mark; Lau, Ching C.; Lecanda, Fernando; Lee, Kyoung-Mu; Lee, Maxwell P.; Le Marchand, Loic; Lerner, Seth P.; Li, Donghui; Liao, Linda M.; Lim, Wei-Yen; Lin, Dongxin; Lin, Jie; Lindstrom, Sara; Linet, Martha S.; Lissowska, Jolanta; Liu, Jianjun; Ljungberg, Börje; Lloreta, Josep; Lu, Daru; Ma, Jing; Malats, Nuria; Mannisto, Satu; Marina, Neyssa; Mastrangelo, Giuseppe; Matsuo, Keitaro; McGlynn, Katherine A.; McKean-Cowdin, Roberta; McNeill, Lorna H.; McWilliams, Robert R.; Melin, Beatrice S.; Meltzer, Paul S.; Mensah, James E.; Miao, Xiaoping; Michaud, Dominique S.; Mondul, Alison M.; Moore, Lee E.; Muir, Kenneth; Niwa, Shelley; Olson, Sara H.; Orr, Nick; Panico, Salvatore; Park, Jae Yong; Patel, Alpa V.; Patino-Garcia, Ana; Pavanello, Sofia; Peeters, Petra H. M.; Peplonska, Beata; Peters, Ulrike; Petersen, Gloria M.; Picci, Piero; Pike, Malcolm C.; Porru, Stefano; Prescott, Jennifer; Pu, Xia; Purdue, Mark P.; Qiao, You-Lin; Rajaraman, Preetha; Riboli, Elio; Risch, Harvey A.; Rodabough, Rebecca J.; Rothman, Nathaniel; Ruder, Avima M.; Ryu, Jeong-Seon; Sanson, Marc; Schned, Alan; Schumacher, Fredrick R.; Schwartz, Ann G.; Schwartz, Kendra L.; Schwenn, Molly; Scotlandi, Katia; Seow, Adeline; Serra, Consol; Serra, Massimo; Sesso, Howard D.; Severi, Gianluca; Shen, Hongbing; Shen, Min; Shete, Sanjay; Shiraishi, Kouya; Shu, Xiao-Ou; Siddiq, Afshan; Sierrasesumaga, Luis; Sierri, Sabina; Loon Sihoe, Alan Dart; Silverman, Debra T.; Simon, Matthias; Southey, Melissa C.; Spector, Logan; Spitz, Margaret; Stampfer, Meir; Stattin, Par; Stern, Mariana C.; Stevens, Victoria L.; Stolzenberg-Solomon, Rachael Z.; Stram, Daniel O.; Strom, Sara S.; Su, Wu-Chou; Sund, Malin; Sung, Sook Whan; Swerdlow, Anthony; Tan, Wen; Tanaka, Hideo; Tang, Wei; Tang, Ze-Zhang; Tardon, Adonina; Tay, Evelyn; Taylor, Philip R.; Tettey, Yao; Thomas, David M.; Tirabosco, Roberto; Tjonneland, Anne; Tobias, Geoffrey S.; Toro, Jorge R.; Travis, Ruth C.; Trichopoulos, Dimitrios; Troisi, Rebecca; Truelove, Ann; Tsai, Ying-Huang; Tucker, Margaret A.; Tumino, Rosario; Van Den Berg, David; Van Den Eeden, Stephen K.; Vermeulen, Roel; Vineis, Paolo; Visvanathan, Kala; Vogel, Ulla; Wang, Chaoyu; Wang, Chengfeng; Wang, Junwen; Wang, Sophia S.; Weiderpass, Elisabete; Weinstein, Stephanie J.; Wentzensen, Nicolas; Wheeler, William; White, Emily; Wiencke, John K.; Wolk, Alicja; Wolpin, Brian M.; Wong, Maria Pik; Wrensch, Margaret; Wu, Chen; Wu, Tangchun; Wu, Xifeng; Wu, Yi-Long; Wunder, Jay S.; Xiang, Yong-Bing; Xu, Jun; Yang, Hannah P.; Yang, Pan-Chyr; Yatabe, Yasushi; Ye, Yuanqing; Yeboah, Edward D.; Yin, Zhihua; Ying, Chen; Yu, Chong-Jen; Yu, Kai; Yuan, Jian-Min; Zanetti, Krista A.; Zeleniuch-Jacquotte, Anne; Zheng, Wei; Zhou, Baosen; Mirabello, Lisa; Savage, Sharon A.; Kraft, Peter; Chanock, Stephen J.; Yeager, Meredith; Landi, Maria Terese; Shi, Jianxin; Chatterjee, Nilanjan; Amundadottir, Laufey T.

2014-01-01

Genome-wide association studies (GWAS) have mapped risk alleles for at least 10 distinct cancers to a small region of 63 000 bp on chromosome 5p15.33. This region harbors the TERT and CLPTM1L genes; the former encodes the catalytic subunit of telomerase reverse transcriptase and the latter may play a role in apoptosis. To investigate further the genetic architecture of common susceptibility alleles in this region, we conducted an agnostic subset-based meta-analysis (association analysis based on subsets) across six distinct cancers in 34 248 cases and 45 036 controls. Based on sequential conditional analysis, we identified as many as six independent risk loci marked by common single-nucleotide polymorphisms: five in the TERT gene (Region 1: rs7726159, P = 2.10 × 10−39; Region 3: rs2853677, P = 3.30 × 10−36 and PConditional = 2.36 × 10−8; Region 4: rs2736098, P = 3.87 × 10−12 and PConditional = 5.19 × 10−6, Region 5: rs13172201, P = 0.041 and PConditional = 2.04 × 10−6; and Region 6: rs10069690, P = 7.49 × 10−15 and PConditional = 5.35 × 10−7) and one in the neighboring CLPTM1L gene (Region 2: rs451360; P = 1.90 × 10−18 and PConditional = 7.06 × 10−16). Between three and five cancers mapped to each independent locus with both risk-enhancing and protective effects. Allele-specific effects on DNA methylation were seen for a subset of risk loci, indicating that methylation and subsequent effects on gene expression may contribute to the biology of risk variants on 5p15.33. Our results provide strong support for extensive pleiotropy across this region of 5p15.33, to an extent not previously observed in other cancer susceptibility loci. PMID:25027329

Imputation and subset-based association analysis across different cancer types identifies multiple independent risk loci in the TERT-CLPTM1L region on chromosome 5p15.33.

PubMed

Wang, Zhaoming; Zhu, Bin; Zhang, Mingfeng; Parikh, Hemang; Jia, Jinping; Chung, Charles C; Sampson, Joshua N; Hoskins, Jason W; Hutchinson, Amy; Burdette, Laurie; Ibrahim, Abdisamad; Hautman, Christopher; Raj, Preethi S; Abnet, Christian C; Adjei, Andrew A; Ahlbom, Anders; Albanes, Demetrius; Allen, Naomi E; Ambrosone, Christine B; Aldrich, Melinda; Amiano, Pilar; Amos, Christopher; Andersson, Ulrika; Andriole, Gerald; Andrulis, Irene L; Arici, Cecilia; Arslan, Alan A; Austin, Melissa A; Baris, Dalsu; Barkauskas, Donald A; Bassig, Bryan A; Beane Freeman, Laura E; Berg, Christine D; Berndt, Sonja I; Bertazzi, Pier Alberto; Biritwum, Richard B; Black, Amanda; Blot, William; Boeing, Heiner; Boffetta, Paolo; Bolton, Kelly; Boutron-Ruault, Marie-Christine; Bracci, Paige M; Brennan, Paul; Brinton, Louise A; Brotzman, Michelle; Bueno-de-Mesquita, H Bas; Buring, Julie E; Butler, Mary Ann; Cai, Qiuyin; Cancel-Tassin, Geraldine; Canzian, Federico; Cao, Guangwen; Caporaso, Neil E; Carrato, Alfredo; Carreon, Tania; Carta, Angela; Chang, Gee-Chen; Chang, I-Shou; Chang-Claude, Jenny; Che, Xu; Chen, Chien-Jen; Chen, Chih-Yi; Chen, Chung-Hsing; Chen, Constance; Chen, Kuan-Yu; Chen, Yuh-Min; Chokkalingam, Anand P; Chu, Lisa W; Clavel-Chapelon, Francoise; Colditz, Graham A; Colt, Joanne S; Conti, David; Cook, Michael B; Cortessis, Victoria K; Crawford, E David; Cussenot, Olivier; Davis, Faith G; De Vivo, Immaculata; Deng, Xiang; Ding, Ti; Dinney, Colin P; Di Stefano, Anna Luisa; Diver, W Ryan; Duell, Eric J; Elena, Joanne W; Fan, Jin-Hu; Feigelson, Heather Spencer; Feychting, Maria; Figueroa, Jonine D; Flanagan, Adrienne M; Fraumeni, Joseph F; Freedman, Neal D; Fridley, Brooke L; Fuchs, Charles S; Gago-Dominguez, Manuela; Gallinger, Steven; Gao, Yu-Tang; Gapstur, Susan M; Garcia-Closas, Montserrat; Garcia-Closas, Reina; Gastier-Foster, Julie M; Gaziano, J Michael; Gerhard, Daniela S; Giffen, Carol A; Giles, Graham G; Gillanders, Elizabeth M; Giovannucci, Edward L; Goggins, Michael; Gokgoz, Nalan; Goldstein, Alisa M; Gonzalez, Carlos; Gorlick, Richard; Greene, Mark H; Gross, Myron; Grossman, H Barton; Grubb, Robert; Gu, Jian; Guan, Peng; Haiman, Christopher A; Hallmans, Goran; Hankinson, Susan E; Harris, Curtis C; Hartge, Patricia; Hattinger, Claudia; Hayes, Richard B; He, Qincheng; Helman, Lee; Henderson, Brian E; Henriksson, Roger; Hoffman-Bolton, Judith; Hohensee, Chancellor; Holly, Elizabeth A; Hong, Yun-Chul; Hoover, Robert N; Hosgood, H Dean; Hsiao, Chin-Fu; Hsing, Ann W; Hsiung, Chao Agnes; Hu, Nan; Hu, Wei; Hu, Zhibin; Huang, Ming-Shyan; Hunter, David J; Inskip, Peter D; Ito, Hidemi; Jacobs, Eric J; Jacobs, Kevin B; Jenab, Mazda; Ji, Bu-Tian; Johansen, Christoffer; Johansson, Mattias; Johnson, Alison; Kaaks, Rudolf; Kamat, Ashish M; Kamineni, Aruna; Karagas, Margaret; Khanna, Chand; Khaw, Kay-Tee; Kim, Christopher; Kim, In-Sam; Kim, Jin Hee; Kim, Yeul Hong; Kim, Young-Chul; Kim, Young Tae; Kang, Chang Hyun; Jung, Yoo Jin; Kitahara, Cari M; Klein, Alison P; Klein, Robert; Kogevinas, Manolis; Koh, Woon-Puay; Kohno, Takashi; Kolonel, Laurence N; Kooperberg, Charles; Kratz, Christian P; Krogh, Vittorio; Kunitoh, Hideo; Kurtz, Robert C; Kurucu, Nilgun; Lan, Qing; Lathrop, Mark; Lau, Ching C; Lecanda, Fernando; Lee, Kyoung-Mu; Lee, Maxwell P; Le Marchand, Loic; Lerner, Seth P; Li, Donghui; Liao, Linda M; Lim, Wei-Yen; Lin, Dongxin; Lin, Jie; Lindstrom, Sara; Linet, Martha S; Lissowska, Jolanta; Liu, Jianjun; Ljungberg, Börje; Lloreta, Josep; Lu, Daru; Ma, Jing; Malats, Nuria; Mannisto, Satu; Marina, Neyssa; Mastrangelo, Giuseppe; Matsuo, Keitaro; McGlynn, Katherine A; McKean-Cowdin, Roberta; McNeill, Lorna H; McWilliams, Robert R; Melin, Beatrice S; Meltzer, Paul S; Mensah, James E; Miao, Xiaoping; Michaud, Dominique S; Mondul, Alison M; Moore, Lee E; Muir, Kenneth; Niwa, Shelley; Olson, Sara H; Orr, Nick; Panico, Salvatore; Park, Jae Yong; Patel, Alpa V; Patino-Garcia, Ana; Pavanello, Sofia; Peeters, Petra H M; Peplonska, Beata; Peters, Ulrike; Petersen, Gloria M; Picci, Piero; Pike, Malcolm C; Porru, Stefano; Prescott, Jennifer; Pu, Xia; Purdue, Mark P; Qiao, You-Lin; Rajaraman, Preetha; Riboli, Elio; Risch, Harvey A; Rodabough, Rebecca J; Rothman, Nathaniel; Ruder, Avima M; Ryu, Jeong-Seon; Sanson, Marc; Schned, Alan; Schumacher, Fredrick R; Schwartz, Ann G; Schwartz, Kendra L; Schwenn, Molly; Scotlandi, Katia; Seow, Adeline; Serra, Consol; Serra, Massimo; Sesso, Howard D; Severi, Gianluca; Shen, Hongbing; Shen, Min; Shete, Sanjay; Shiraishi, Kouya; Shu, Xiao-Ou; Siddiq, Afshan; Sierrasesumaga, Luis; Sierri, Sabina; Loon Sihoe, Alan Dart; Silverman, Debra T; Simon, Matthias; Southey, Melissa C; Spector, Logan; Spitz, Margaret; Stampfer, Meir; Stattin, Par; Stern, Mariana C; Stevens, Victoria L; Stolzenberg-Solomon, Rachael Z; Stram, Daniel O; Strom, Sara S; Su, Wu-Chou; Sund, Malin; Sung, Sook Whan; Swerdlow, Anthony; Tan, Wen; Tanaka, Hideo; Tang, Wei; Tang, Ze-Zhang; Tardon, Adonina; Tay, Evelyn; Taylor, Philip R; Tettey, Yao; Thomas, David M; Tirabosco, Roberto; Tjonneland, Anne; Tobias, Geoffrey S; Toro, Jorge R; Travis, Ruth C; Trichopoulos, Dimitrios; Troisi, Rebecca; Truelove, Ann; Tsai, Ying-Huang; Tucker, Margaret A; Tumino, Rosario; Van Den Berg, David; Van Den Eeden, Stephen K; Vermeulen, Roel; Vineis, Paolo; Visvanathan, Kala; Vogel, Ulla; Wang, Chaoyu; Wang, Chengfeng; Wang, Junwen; Wang, Sophia S; Weiderpass, Elisabete; Weinstein, Stephanie J; Wentzensen, Nicolas; Wheeler, William; White, Emily; Wiencke, John K; Wolk, Alicja; Wolpin, Brian M; Wong, Maria Pik; Wrensch, Margaret; Wu, Chen; Wu, Tangchun; Wu, Xifeng; Wu, Yi-Long; Wunder, Jay S; Xiang, Yong-Bing; Xu, Jun; Yang, Hannah P; Yang, Pan-Chyr; Yatabe, Yasushi; Ye, Yuanqing; Yeboah, Edward D; Yin, Zhihua; Ying, Chen; Yu, Chong-Jen; Yu, Kai; Yuan, Jian-Min; Zanetti, Krista A; Zeleniuch-Jacquotte, Anne; Zheng, Wei; Zhou, Baosen; Mirabello, Lisa; Savage, Sharon A; Kraft, Peter; Chanock, Stephen J; Yeager, Meredith; Landi, Maria Terese; Shi, Jianxin; Chatterjee, Nilanjan; Amundadottir, Laufey T

2014-12-15

Genome-wide association studies (GWAS) have mapped risk alleles for at least 10 distinct cancers to a small region of 63 000 bp on chromosome 5p15.33. This region harbors the TERT and CLPTM1L genes; the former encodes the catalytic subunit of telomerase reverse transcriptase and the latter may play a role in apoptosis. To investigate further the genetic architecture of common susceptibility alleles in this region, we conducted an agnostic subset-based meta-analysis (association analysis based on subsets) across six distinct cancers in 34 248 cases and 45 036 controls. Based on sequential conditional analysis, we identified as many as six independent risk loci marked by common single-nucleotide polymorphisms: five in the TERT gene (Region 1: rs7726159, P = 2.10 × 10(-39); Region 3: rs2853677, P = 3.30 × 10(-36) and PConditional = 2.36 × 10(-8); Region 4: rs2736098, P = 3.87 × 10(-12) and PConditional = 5.19 × 10(-6), Region 5: rs13172201, P = 0.041 and PConditional = 2.04 × 10(-6); and Region 6: rs10069690, P = 7.49 × 10(-15) and PConditional = 5.35 × 10(-7)) and one in the neighboring CLPTM1L gene (Region 2: rs451360; P = 1.90 × 10(-18) and PConditional = 7.06 × 10(-16)). Between three and five cancers mapped to each independent locus with both risk-enhancing and protective effects. Allele-specific effects on DNA methylation were seen for a subset of risk loci, indicating that methylation and subsequent effects on gene expression may contribute to the biology of risk variants on 5p15.33. Our results provide strong support for extensive pleiotropy across this region of 5p15.33, to an extent not previously observed in other cancer susceptibility loci. Published by Oxford University Press 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Identification of supernumerary ring chromosome 1 mosaicism using fluorescence in situ hybridization.

PubMed

Chen, H; Tuck-Muller, C M; Batista, D A; Wertelecki, W

1995-03-27

We report on a 15-year-old black boy with severe mental retardation, multiple congenital anomalies, and a supernumerary ring chromosome mosaicism. Fluorescence in situ hybridization with a chromosome 1 painting probe (pBS1) identified the ring as derived from chromosome 1. The karyotype was 46,XY/47,XY,+r(1)(p13q23). A review showed 8 reports of ring chromosome 1. In 5 cases, the patients had a non-supernumerary ring chromosome 1 resulting in partial monosomies of the short and/or long arm of chromosome 1. In 3 cases, the presence of a supernumerary ring resulted in partial trisomy of different segments of chromosome 1. In one of these cases the supernumerary ring was composed primarily of the centromere and the heterochromatic region of chromosome 1, resulting in normal phenotype. Our patient represents the third report of a supernumerary ring chromosome 1 resulting in abnormal phenotype.

Similarities in the chromosomal distribution of AG and AC repeats within and between Drosophila, human and barley chromosomes.

PubMed

Cuadrado, A; Jouve, N

2007-01-01

Two simple sequence repeats (SSRs), AG and AC, were mapped directly in the metaphase chromosomes of man and barley (Hordeum vulgare L.), and in the metaphase and polytene chromosomes of Drosophila melanogaster. To this end, synthetic oligonucleotides corresponding to (AG)(12) and (AC)(8) were labelled by the random primer technique and used as probes in fluorescent in situ hybridisation (FISH) under high stringency and strict washing conditions. The distribution and intensity of the signals for the repeat sequences were found to be characteristic of the chromosomes and genomes of the three species analysed. The AC repeat sites were uniformly dispersed along the euchromatic segments of all three genomes; in fact, they were largely excluded from the heterochromatin. The Drosophila genome showed a high density of AC sequences on the X chromosome in both mitotic and polytene nuclei. In contrast, the AG repeats were associated with the euchromatic regions of the polytene chromosomes (and in high density on the X chromosome), but were only seen in specific heterochromatic regions in the mitotic chromosomes of all three species. In Drosophila, the AG repeats were exclusively distributed on the tips of the Y chromosome and near the centromere on both arms of chromosome 2. In barley and man, AG repeats were associated with the centromeres (of all chromosomes) and nucleolar organizer regions, respectively. The conserved chromosome distribution of AC within and between these three phylogenetically distant species, and the association of AG in specific chromosome regions with structural or functional properties, suggests that long clusters of these repeats may have some, as yet unknown, role. Copyright (c) 2007 S. Karger AG, Basel.

Identifying homomorphic sex chromosomes from wild-caught adults with limited genomic resources.

PubMed

Brelsford, Alan; Lavanchy, Guillaume; Sermier, Roberto; Rausch, Anna; Perrin, Nicolas

2017-07-01

We demonstrate a genotyping-by-sequencing approach to identify homomorphic sex chromosomes and their homolog in a distantly related reference genome, based on noninvasive sampling of wild-caught individuals, in the moor frog Rana arvalis. Double-digest RADseq libraries were generated using buccal swabs from 30 males and 21 females from the same population. Search for sex-limited markers from the unfiltered data set (411 446 RAD tags) was more successful than searches from a filtered data set (33 073 RAD tags) for markers showing sex differences in heterozygosity or in allele frequencies. Altogether, we obtained 292 putatively sex-linked RAD loci, 98% of which point to male heterogamety. We could map 15 of them to the Xenopus tropicalis genome, all but one on chromosome pair 1, which seems regularly co-opted for sex determination among amphibians. The most efficient mapping strategy was a three-step hierarchical approach, where R. arvalis reads were first mapped to a low-coverage genome of Rana temporaria (17 My divergence), then the R. temporaria scaffolds to the Nanorana parkeri genome (90 My divergence), and finally the N. parkeri scaffolds to the X. tropicalis genome (210 My). We validated our conclusions with PCR primers amplifying part of Dmrt1, a candidate sex determination gene mapping to chromosome 1: a sex-diagnostic allele was present in all 30 males but in none of the 21 females. Our approach is likely to be productive in many situations where biological samples and/or genomic resources are limited. © 2016 John Wiley & Sons Ltd.

Mapping of the bcl-2 oncogene on mouse chromosome 1.

PubMed

Mock, B A; Givol, D; D'Hoostelaere, L A; Huppi, K; Seldin, M F; Gurfinkel, N; Unger, T; Potter, M; Mushinski, J F

1988-01-01

Two bcl-2 alleles have been identified in inbred strains of mice by restriction fragment length polymorphism (RFLP). Analysis of a bcl-2 RFLP in a series of bilineal congenic strains (C.D2), developed as a tool for chromosomal mapping studies, revealed linkage of bcl-2 to the Idh-1/Pep-3 region of murine chromosome 1. The co-segregation of bcl-2 alleles with allelic forms of two other chromosome 1 loci, Ren-1,2 and Spna-1, in a set of back-cross progeny, positions bcl-2 7.8 cM centromeric from Ren-1,2.

Segmental Duplications in Euchromatic Regions of Human Chromosome 5: A Source of Evolutionary Instability and Transcriptional Innovation

PubMed Central

Courseaux, Anouk; Richard, Florence; Grosgeorge, Josiane; Ortola, Christine; Viale, Agnes; Turc-Carel, Claude; Dutrillaux, Bernard; Gaudray, Patrick; Nahon, Jean-Louis

2003-01-01

Recent analyses of the structure of pericentromeric and subtelomeric regions have revealed that these particular regions of human chromosomes are often composed of blocks of duplicated genomic segments that have been associated with rapid evolutionary turnover among the genomes of closely related primates. In the present study, we show that euchromatic regions of human chromosome 5—5p14, 5p13, 5q13, 5q15–5q21—also display such an accumulation of segmental duplications. The structure, organization and evolution of those primate-specific sequences were studied in detail by combining in silico and comparative FISH analyses on human, chimpanzee, gorilla, orangutang, macaca, and capuchin chromosomes. Our results lend support to a two-step model of transposition duplication in the euchromatic regions, with a founder insertional event at the time of divergence between Platyrrhini and Catarrhini (25–35 million years ago) and an apparent burst of inter- and intrachromosomal duplications in the Hominidae lineage. Furthermore, phylogenetic analysis suggests that the chronology and, likely, molecular mechanisms, differ regarding the region of primary insertion—euchromatic versus pericentromeric regions. Lastly, we show that as their counterparts located near the heterochromatic region, the euchromatic segmental duplications have consistently reshaped their region of insertion during primate evolution, creating putative mosaic genes, and they are obvious candidates for causing ectopic rearrangements that have contributed to evolutionary/genomic instability. [Supplemental material is available online at www.genome.org. The following individuals kindly provided reagents, samples, or unpublished information as indicated in the paper: D. Le Paslier, A. McKenzie, J. Melki, C. Sargent, J. Scharf and S. Selig.] PMID:12618367

The gametocidal chromosome as a tool for chromosome manipulation in wheat.

PubMed

Endo, T R

2007-01-01

Many alien chromosomes have been introduced into common wheat (the genus Triticum) from related wild species (the genus Aegilops). Some alien chromosomes have unique genes that secure their existence in the host by causing chromosome breakage in the gametes lacking them. Such chromosomes or genes, called gametocidal (Gc) chromosomes or Gc genes, are derived from different genomes (C, S, S(l) and M(g)) and belong to three different homoeologous groups 2, 3 and 4. The Gc genes of the C and M(g) genomes induce mild, or semi-lethal, chromosome mutations in euploid and alien addition lines of common wheat. Thus, induced chromosomal rearrangements have been identified and established in wheat stocks carrying deletions of wheat and alien (rye and barley) chromosomes or wheat-alien translocations. The gametocidal chromosomes isolated in wheat to date are reviewed here, focusing on their feature as a tool for chromosome manipulation.

A complete YAC contig of the Prader-Willi/Angelman chromosome region (15q11-q13) and refined localization of the SNRPN gene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mutirangura, A.; Jayakumar, A.; Sutcliffe, J.S.

1993-12-01

Since a previous report of a partial YAC contig of the Prader-Willi/Angelman chromosome region (15q11-q13), a complete contig spanning approximately 3.5 Mb has been developed. YACs were isolated from two human genomic libraries by PCR and hybridization screening methods. Twenty-three sequence-tagged sites (STSs) were mapped within the contig, a density of [approximately]1 per 200 kb. Overlaps between YAC clones were identified by Alu-PCR dot-blot analysis and confirmed by STS mapping or hybridization with ends of YAC inserts. The gene encoding small nuclear ribonucleoprotein-associated peptide N (SNRPN), recently identified as a candidate gene for Prader-Willi syndrome, was localized within this contigmore » between markers PW71 and TD3-21. Loci mapped within and immediately flanking the Prader-Willi/Angelman chromosome region contig are ordered as follows: cen-IR39-ML34-IR4-3R-TD189-1-PW71-SNRPN-TD3-21-LS6-1-GABRB3,D15S97-GABRA5-IR10-1-CMW1-tel. This YAC contig will be a useful resource for more detailed physical mapping of the region, for generation of new DNA markers, and for mapping or cloning candidate genes for the Prader-Willi and Angelman syndromes. 36 refs., 2 figs., 2 tabs.« less

Replication pattern of the pericentromeric region of chromosome 10q and expression of the RET protooncogene.

PubMed

Cinti, R; Schena, F; Passalacqua, M; Ceccherini, I; Ravazzolo, R

2004-08-15

Regulation of the RET gene is highly specific during embryo development and is strictly tissue-specific. Control of transcription depends on mechanisms influenced by epigenetic processes, in particular, histone acetylation at regions flanking the 5' end of the gene. Since the RET gene is mapped in the pericentromeric region of the human chromosome 10, the implication of epigenetic processes is even more striking and worth to be investigated in an extended chromosomal tract. One experimental approach to study the chromatin status in relationship with gene transcription is to assess the replication timing, which we did by using fluorescent in situ hybridization in cells expressing or not expressing the RET gene. By using probes spanning a 700-kb genomic region from the RET locus toward the centromere, we found a relationship between RET expression and early replication. Different patterns were observed between cells naturally expressing RET and cells induced to expression of RET by treatment with sodium butyrate, an inhibitor of histone deacetylases. Three-dimensional analysis of the nuclear localization of fluorescent signals by confocal microscopy showed difference of localization between the RET probe and a probe for a housekeeping gene, G3PDH, located at 12p13.3, in cells that do not express RET, in accordance with previous data for other genes and chromosomal regions. However, RET-expressing cells showed a localization of signals which was not consistent with that expected for expressed genes.

Plant Sex Chromosomes.

PubMed

Charlesworth, Deborah

2016-04-29

Although individuals in most flowering plant species, and in many haploid plants, have both sex functions, dioecious species-in which individuals have either male or female functions only-are scattered across many taxonomic groups, and many species have genetic sex determination. Among these, some have visibly heteromorphic sex chromosomes, and molecular genetic studies are starting to uncover sex-linked markers in others, showing that they too have fully sex-linked regions that are either too small or are located in chromosomes that are too small to be cytologically detectable from lack of pairing, lack of visible crossovers, or accumulation of heterochromatin. Detailed study is revealing that, like animal sex chromosomes, plant sex-linked regions show evidence for accumulation of repetitive sequences and genetic degeneration. Estimating when recombination stopped confirms the view that many plants have young sex-linked regions, making plants of great interest for studying the timescale of these changes.

InterB multigenic family, a gene repertoire associated with subterminal chromosome regions of Encephalitozoon cuniculi and conserved in several human-infecting microsporidian species.

PubMed

Dia, Ndongo; Lavie, Laurence; Méténier, Guy; Toguebaye, Bhen S; Vivarès, Christian P; Cornillot, Emmanuel

2007-03-01

Microsporidia are fungi-related obligate intracellular parasites that infect numerous animals, including man. Encephalitozoon cuniculi harbours a very small genome (2.9 Mbp) with about 2,000 coding sequences (CDSs). Most repeated CDSs are of unknown function and are distributed in subterminal regions that mark the transitions between subtelomeric rDNA units and chromosome cores. A potential multigenic family (interB) encoding proteins within a size range of 579-641 aa was investigated by PCR and RT-PCR. Thirty members were finally assigned to the E. cuniculi interB family and a predominant interB transcript was found to originate from a newly identified gene on chromosome III. Microsporidian species from eight different genera infecting insects, fishes or mammals, were tested for a possible intra-phylum conservation of interB genes. Only representatives of the Encephalitozoon, Vittaforma and Brachiola genera, differing in host range but all able to invade humans, were positive. Molecular karyotyping of Brachiola algerae showed a complex set of chromosome bands, providing a haploid genome size estimate of 15-20 Mbp. In spite of this large difference in genome complexity, B. algerae and E. cuniculi shared some similar interB gene copies and a common location of interB genes in near-rDNA subterminal regions.

Methods for chromosome-specific staining

DOEpatents

Gray, J.W.; Pinkel, D.

1995-09-05

Methods and compositions for chromosome-specific staining are provided. Compositions comprise heterogeneous mixtures of labeled nucleic acid fragments having substantially complementary base sequences to unique sequence regions of the chromosomal DNA for which their associated staining reagent is specific. Methods include ways for making the chromosome-specific staining compositions of the invention, and methods for applying the staining compositions to chromosomes. 3 figs.

Methods for chromosome-specific staining

DOEpatents

Gray, Joe W.; Pinkel, Daniel

1995-01-01

Methods and compositions for chromosome-specific staining are provided. Compositions comprise heterogenous mixtures of labeled nucleic acid fragments having substantially complementary base sequences to unique sequence regions of the chromosomal DNA for which their associated staining reagent is specific. Methods include methods for making the chromosome-specific staining compositions of the invention, and methods for applying the staining compositions to chromosomes.

Replication profile of Saccharomyces cerevisiae chromosome VI.

PubMed

Friedman, K L; Brewer, B J; Fangman, W L

1997-11-01

An understanding of the replication programme at the genome level will require the identification and characterization of origins of replication through large, contiguous regions of DNA. As a step toward this goal, origin efficiencies and replication times were determined for 10 ARSs spanning most of the 270 kilobase (kb) chromosome VI of Saccharomyces cerevisiae. Chromosome VI shows a wide variation in the percentage of cell cycles in which different replication origins are utilized. Most of the origins are activated in only a fraction of cells, suggesting that the pattern of origin usage on chromosome VI varies greatly within the cell population. The replication times of fragments containing chromosome VI origins show a temporal pattern that has been recognized on other chromosomes--the telomeres replicate late in S phase, while the central region of the chromosome replicates early. As demonstrated here for chromosome VI, analysis of the direction of replication fork movement along a chromosome and determination of replication time by measuring a period of hemimethylation may provide an efficient means of surveying origin activity over large regions of the genome.

Accessories make the outfit: Accessory Chromosomes and other dispensable DNA regions in plant-pathogenic Fungi.

PubMed

Bertazzoni, Stefania; Williams, Angela; Jones, Darcy A B; Syme, Robert A; Tan, Kar-Chun; Hane, James Kyawzwar

2018-04-17

Fungal pathogen genomes can often be divided into core and accessory regions. Accessory regions may be comprised of either accessory regions (ARs) within core chromosomes (CCs), or wholly-dispensable (accessory) chromosomes (ACs). Fungal ACs and ARs typically accumulate mutations and structural rearrangements more rapidly over time than CCs, and many harbour genes relevant to host-pathogen interactions. These regions are of particular interest in plant pathology and include host-specific virulence factors and secondary metabolite synthesis gene clusters. This review outlines known ACs and ARs in fungal genomes, methods used for their detection, their common properties that differentiate them from the core genome, and what is currently known of their various roles in pathogenicity. Reports on the evolutionary processes generating and shaping AC/AR compartments are discussed, including repeat induced point mutation (RIP) and breakage-fusion-bridge (BFB) cycles. Previously ACs have been studied extensively within key genera including Fusarium, Zymoseptoria and Alternaria, but are growing in their frequency of observation and perceived importance across a wider range of fungal species. Recent advances in sequencing technologies permit affordable genome assembly and re-sequencing of populations that will facilitate further discovery and routine screening of ACs.

Genome-wide association and regional heritability mapping to identify loci underlying variation in nematode resistance and body weight in Scottish Blackface lambs

PubMed Central

Riggio, V; Matika, O; Pong-Wong, R; Stear, M J; Bishop, S C

2013-01-01

The genetic architecture underlying nematode resistance and body weight in Blackface lambs was evaluated comparing genome-wide association (GWA) and regional heritability mapping (RHM) approaches. The traits analysed were faecal egg count (FEC) and immunoglobulin A activity against third-stage larvae from Teladorsagia circumcincta, as indicators of nematode resistance, and body weight in a population of 752 Scottish Blackface lambs, genotyped with the 50k single-nucleotide polymorphism (SNP) chip. FEC for both Nematodirus and Strongyles nematodes (excluding Nematodirus), as well as body weight were collected at approximately 16, 20 and 24 weeks of age. In addition, a weighted average animal effect was estimated for both FEC and body weight traits. After quality control, 44 388 SNPs were available for the GWA analysis and 42 841 for the RHM, which utilises only mapped SNPs. The same fixed effects were used in both analyses: sex, year, management group, litter size and age of dam, with day of birth as covariate. Some genomic regions of interest for both nematode resistance and body weight traits were identified, using both GWA and RHM approaches. For both methods, strong evidence for association was found on chromosome 14 for Nematodirus average animal effect, chromosome 6 for Strongyles FEC at 16 weeks and chromosome 6 for body weight at 16 weeks. Across the entire data set, RHM identified more regions reaching the suggestive level than GWA, suggesting that RHM is capable of capturing some of the variation not detected by GWA analyses. PMID:23512009

Ancestral Chromosomal Blocks Are Triplicated in Brassiceae Species with Varying Chromosome Number and Genome Size1

PubMed Central

Lysak, Martin A.; Cheung, Kwok; Kitschke, Michaela; Bureš, Petr

2007-01-01

The paleopolyploid character of genomes of the economically important genus Brassica and closely related species (tribe Brassiceae) is still fairly controversial. Here, we report on the comparative painting analysis of block F of the crucifer Ancestral Karyotype (AK; n = 8), consisting of 24 conserved genomic blocks, in 10 species traditionally treated as members of the tribe Brassiceae. Three homeologous copies of block F were identified per haploid chromosome complement in Brassiceae species with 2n = 14, 18, 20, 32, and 36. In high-polyploid (n ≥ 30) species Crambe maritima (2n = 60), Crambe cordifolia (2n = 120), and Vella pseudocytisus (2n = 68), six, 12, and six copies of the analyzed block have been revealed, respectively. Homeologous regions resembled the ancestral structure of block F within the AK or were altered by inversions and/or translocations. In two species of the subtribe Zillineae, two of the three homeologous regions were combined via a reciprocal translocation onto one chromosome. Altogether, these findings provide compelling evidence of an ancient hexaploidization event and corresponding whole-genome triplication shared by the tribe Brassiceae. No direct relationship between chromosome number and genome size variation (1.2–2.5 pg/2C) has been found in Brassiceae species with 2n = 14 to 36. Only two homeologous copies of block F suggest a whole-genome duplication but not the triplication event in Orychophragmus violaceus (2n = 24), and confirm a phylogenetic position of this species outside the tribe Brassiceae. Chromosome duplication detected in Orychophragmus as well as chromosome rearrangements shared by Zillineae species demonstrate the usefulness of comparative cytogenetics for elucidation of phylogenetic relationships. PMID:17720758

X Chromosome Control of Meiotic Chromosome Synapsis in Mouse Inter-Subspecific Hybrids

PubMed Central

Bhattacharyya, Tanmoy; Reifova, Radka; Gregorova, Sona; Simecek, Petr; Gergelits, Vaclav; Mistrik, Martin; Martincova, Iva; Pialek, Jaroslav; Forejt, Jiri

2014-01-01

Hybrid sterility (HS) belongs to reproductive isolation barriers that safeguard the integrity of species in statu nascendi. Although hybrid sterility occurs almost universally among animal and plant species, most of our current knowledge comes from the classical genetic studies on Drosophila interspecific crosses or introgressions. With the house mouse subspecies Mus m. musculus and Mus m. domesticus as a model, new research tools have become available for studies of the molecular mechanisms and genetic networks underlying HS. Here we used QTL analysis and intersubspecific chromosome substitution strains to identify a 4.7 Mb critical region on Chromosome X (Chr X) harboring the Hstx2 HS locus, which causes asymmetrical spermatogenic arrest in reciprocal intersubspecific F1 hybrids. Subsequently, we mapped autosomal loci on Chrs 3, 9 and 13 that can abolish this asymmetry. Combination of immunofluorescent visualization of the proteins of synaptonemal complexes with whole-chromosome DNA FISH on pachytene spreads revealed that heterosubspecific, unlike consubspecific, homologous chromosomes are predisposed to asynapsis in F1 hybrid male and female meiosis. The asynapsis is under the trans- control of Hstx2 and Hst1/Prdm9 hybrid sterility genes in pachynemas of male but not female hybrids. The finding concurred with the fertility of intersubpecific F1 hybrid females homozygous for the Hstx2Mmm allele and resolved the apparent conflict with the dominance theory of Haldane's rule. We propose that meiotic asynapsis in intersubspecific hybrids is a consequence of cis-acting mismatch between homologous chromosomes modulated by the trans-acting Hstx2 and Prdm9 hybrid male sterility genes. PMID:24516397

X chromosome control of meiotic chromosome synapsis in mouse inter-subspecific hybrids.

PubMed

Bhattacharyya, Tanmoy; Reifova, Radka; Gregorova, Sona; Simecek, Petr; Gergelits, Vaclav; Mistrik, Martin; Martincova, Iva; Pialek, Jaroslav; Forejt, Jiri

2014-02-01

Hybrid sterility (HS) belongs to reproductive isolation barriers that safeguard the integrity of species in statu nascendi. Although hybrid sterility occurs almost universally among animal and plant species, most of our current knowledge comes from the classical genetic studies on Drosophila interspecific crosses or introgressions. With the house mouse subspecies Mus m. musculus and Mus m. domesticus as a model, new research tools have become available for studies of the molecular mechanisms and genetic networks underlying HS. Here we used QTL analysis and intersubspecific chromosome substitution strains to identify a 4.7 Mb critical region on Chromosome X (Chr X) harboring the Hstx2 HS locus, which causes asymmetrical spermatogenic arrest in reciprocal intersubspecific F1 hybrids. Subsequently, we mapped autosomal loci on Chrs 3, 9 and 13 that can abolish this asymmetry. Combination of immunofluorescent visualization of the proteins of synaptonemal complexes with whole-chromosome DNA FISH on pachytene spreads revealed that heterosubspecific, unlike consubspecific, homologous chromosomes are predisposed to asynapsis in F1 hybrid male and female meiosis. The asynapsis is under the trans- control of Hstx2 and Hst1/Prdm9 hybrid sterility genes in pachynemas of male but not female hybrids. The finding concurred with the fertility of intersubpecific F1 hybrid females homozygous for the Hstx2(Mmm) allele and resolved the apparent conflict with the dominance theory of Haldane's rule. We propose that meiotic asynapsis in intersubspecific hybrids is a consequence of cis-acting mismatch between homologous chromosomes modulated by the trans-acting Hstx2 and Prdm9 hybrid male sterility genes.

A genome-wide association study for body weight in Japanese Thoroughbred racehorses clarifies candidate regions on chromosomes 3, 9, 15, and 18

PubMed Central

TOZAKI, Teruaki; KIKUCHI, Mio; KAKOI, Hironaga; HIROTA, Kei-ichi; NAGATA, Shun-ichi

2017-01-01

ABSTRACT Body weight is an important trait to confirm growth and development in humans and animals. In Thoroughbred racehorses, it is measured in the postnatal, training, and racing periods to evaluate growth and training degrees. The body weight of mature Thoroughbred racehorses generally ranges from 400 to 600 kg, and this broad range is likely influenced by environmental and genetic factors. Therefore, a genome-wide association study (GWAS) using the Equine SNP70 BeadChip was performed to identify the genomic regions associated with body weight in Japanese Thoroughbred racehorses using 851 individuals. The average body weight of these horses was 473.9 kg (standard deviation: 28.0) at the age of 3, and GWAS identified statistically significant SNPs on chromosomes 3 (BIEC2_808466, P=2.32E-14), 9 (BIEC2_1105503, P=1.03E-7), 15 (BIEC2_322669, P=9.50E-6), and 18 (BIEC2_417274, P=1.44E-14), which were associated with body weight as a quantitative trait. The genomic regions on chromosomes 3, 9, 15, and 18 included ligand-dependent nuclear receptor compressor-like protein (LCORL), zinc finger and AT hook domain containing (ZFAT), tribbles pseudokinase 2 (TRIB2), and myostatin (MSTN), respectively, as candidate genes. LCORL and ZFAT are associated with withers height in horses, whereas MSTN affects muscle mass. Thus, the genomic regions identified in this study seem to affect the body weight of Thoroughbred racehorses. Although this information is useful for breeding and growth management of the horses, the production of genetically modified animals and gene doping (abuse/misuse of gene therapy) should be prohibited to maintain horse racing integrity. PMID:29270069

A comprehensive screen for SNP associations on chromosome region 5q31-33 in Swedish/Norwegian celiac disease families.

PubMed

Amundsen, Silja Svanstrøm; Adamovic, Svetlana; Hellqvist, Asa; Nilsson, Staffan; Gudjónsdóttir, Audur H; Ascher, Henry; Ek, Johan; Larsson, Kristina; Wahlström, Jan; Lie, Benedicte A; Sollid, Ludvig M; Naluai, Asa Torinsson

2007-09-01

Celiac disease (CD) is a gluten-induced enteropathy, which results from the interplay between environmental and genetic factors. There is a strong human leukocyte antigen (HLA) association with the disease, and HLA-DQ alleles represent a major genetic risk factor. In addition to HLA-DQ, non-HLA genes appear to be crucial for CD development. Chromosomal region 5q31-33 has demonstrated linkage with CD in several genome-wide studies, including in our Swedish/Norwegian cohort. In a European meta-analysis 5q31-33 was the only region that reached a genome-wide level of significance except for the HLA region. To identify the genetic variant(s) responsible for this linkage signal, we performed a comprehensive single nucleotide polymorphism (SNP) association screen in 97 Swedish/Norwegian multiplex families who demonstrate linkage to the region. We selected tag SNPs from a 16 Mb region representing the 95% confidence interval of the linkage peak. A total of 1,404 SNPs were used for the association analysis. We identified several regions with SNPs demonstrating moderate single- or multipoint associations. However, the isolated association signals appeared insufficient to account for the linkage signal seen in our cohort. Collective effects of multiple risk genes within the region, incomplete genetic coverage or effects related to copy number variation are possible explanations for our findings.

Amplification of chromosomal DNA in situ

DOEpatents

Christian, Allen T.; Coleman, Matthew A.; Tucker, James D.

2002-01-01

Amplification of chromosomal DNA in situ to increase the amount of DNA associated with a chromosome or chromosome region is described. The amplification of chromosomal DNA in situ provides for the synthesis of Fluorescence in situ Hybridization (FISH) painting probes from single dissected chromosome fragments, the production of cDNA libraries from low copy mRNAs and improved in Comparative Genomic Hybridization (CGH) procedures.

Nucleolar organizer regions in Sittasomus griseicapillus and Lepidocolaptes angustirostris (Aves, Dendrocolaptidae): Evidence of a chromosome inversion.

PubMed

de Oliveira Barbosa, Marcelo; da Silva, Rubens Rodrigues; de Sena Correia, Vanessa Carolina; Dos Santos, Luana Pereira; Garnero, Analía Del Valle; Gunski, Ricardo José

2013-03-01

Cytogenetic studies in birds are still scarce compared to other vertebrates. Woodcreepers (Dendrocolaptidae) are part of a highly specialized group within the Suboscines of the New World. They are forest birds exclusive to the Neotropical region and similar to woodpeckers, at a comparable evolutionary stage. This paper describes for the first time the karyotypes of the Olivaceous and the Narrow-billed Woodcreeper using conventional staining with Giemsa and silver nitrate staining of the nucleolar organizer regions (Ag-NORs). Metaphases were obtained by fibular bone marrow culture. The chromosome number of the Olivaceous Woodcreeper was 2n = 82 and of the Narrow-billed Woodcreeper, 2n = 82. Ag-NORs in the largest macrochromosome pair and evidence of a chromosome inversion are described herein for the first time for this group.

Genome-Wide Analysis in Three Fusarium Pathogens Identifies Rapidly Evolving Chromosomes and Genes Associated with Pathogenicity

PubMed Central

Sperschneider, Jana; Gardiner, Donald M.; Thatcher, Louise F.; Lyons, Rebecca; Singh, Karam B.; Manners, John M.; Taylor, Jennifer M.

2015-01-01

Pathogens and hosts are in an ongoing arms race and genes involved in host–pathogen interactions are likely to undergo diversifying selection. Fusarium plant pathogens have evolved diverse infection strategies, but how they interact with their hosts in the biotrophic infection stage remains puzzling. To address this, we analyzed the genomes of three Fusarium plant pathogens for genes that are under diversifying selection. We found a two-speed genome structure both on the chromosome and gene group level. Diversifying selection acts strongly on the dispensable chromosomes in Fusarium oxysporum f. sp. lycopersici and on distinct core chromosome regions in Fusarium graminearum, all of which have associations with virulence. Members of two gene groups evolve rapidly, namely those that encode proteins with an N-terminal [SG]-P-C-[KR]-P sequence motif and proteins that are conserved predominantly in pathogens. Specifically, 29 F. graminearum genes are rapidly evolving, in planta induced and encode secreted proteins, strongly pointing toward effector function. In summary, diversifying selection in Fusarium is strongly reflected as genomic footprints and can be used to predict a small gene set likely to be involved in host–pathogen interactions for experimental verification. PMID:25994930

Chromosomal Mapping of Repetitive DNAs in Myiopsitta monachus and Amazona aestiva (Psittaciformes, Psittacidae) with Emphasis on the Sex Chromosomes.

PubMed

de Oliveira Furo, Ivanete; Kretschmer, Rafael; Dos Santos, Michelly S; de Lima Carvalho, Carlos A; Gunski, Ricardo J; O'Brien, Patrícia C M; Ferguson-Smith, Malcolm A; Cioffi, Marcelo B; de Oliveira, Edivaldo H C

2017-01-01

Here, for the first time, we describe the karyotype of Myiopsitta monachus (Psittacidae, Arini). We found 2n = 48, corresponding to the lowest diploid number observed in Neotropical Psittaciformes so far, with an uncommonly large W chromosome homomorphic to the Z. In order to better understand the evolution of the sex chromosomes in this species, we applied several molecular cytogenetic approaches, including C-banding, FISH mapping of repetitive DNAs (several microsatellite repeats), and whole-chromosome painting on metaphases of M. monachus. For comparison, another species belonging to the same tribe but with a smaller W chromosome (A. aestiva) was also analyzed. The results show that the constitutive heterochromatin has a very diverse distribution pattern in these species revealing heterochromatic blocks in the centromeric region of all chromosomes and in most of the length of the W chromosome in A. aestiva, while in M. monachus they were found in interstitial and telomeric regions. Concerning the microsatellites, only the sequence (CG)n produced signals on the W chromosome of A. aestiva, in the distal region of both arms. However, in M. monachus, (CAA)n, (CAG)n, and (CG)n probes were accumulated on the W chromosome, and, in addition, the sequence (CAG)n also hybridized to heterochromatic regions in macrochromosomes, as well as in microchromosomes. Based on these results, we suggest that the increase in length of the W chromosome in M. monachus is due to the amplification of repetitive elements, which highlights their significant role in the evolutionary process of sex chromosome differentiation. © 2017 S. Karger AG, Basel.

Genetic and radiation hybrid mapping of the hyperekplexia region on chromosome 5q.

PubMed Central

Ryan, S G; Dixon, M J; Nigro, M A; Kelts, K A; Markand, O N; Terry, J C; Shiang, R; Wasmuth, J J; O'Connell, P

1992-01-01

Hyperekplexia, or startle disease (STHE), is an autosomal dominant neurologic disorder characterized by muscular rigidity of central nervous system origin, particularly in the neonatal period, and by an exaggerated startle response to sudden, unexpected acoustic or tactile stimuli. STHE responds dramatically to the benzodiazepine drug clonazepam, which acts at gamma-aminobutyric acid type A (GABA-A) receptors. The STHE locus (STHE) was recently assigned to chromosome 5q, on the basis of tight linkage to the colony-stimulating factor 1-receptor (CSF1-R) locus in a single large family. We performed linkage analysis in the original and three additional STHE pedigrees with eight chromosome 5q microsatellite markers and placed several of the most closely linked markers on an existing radiation hybrid (RH) map of the region. The results provide strong evidence for genetic locus homogeneity and assign STHE to a 5.9-cM interval defined by CSF1-R and D5S379, which are separated by an RH map distance of 74 centirays (roughly 2.2-3.7 Mb). Two polymorphic markers (D5S119 and D5S209) lie within this region, but they could not be ordered with respect to STHE. RH mapping eliminated the candidate genes GABRA1 and GABRG2, which encode GABA-A receptor components, by showing that they are telomeric to the target region. PMID:1334371

Meiotic cytology and chromosome behaviour in wild-type Arabidopsis thaliana.

PubMed

Armstrong, Susan J; Jones, Gareth H

2003-01-01

This article reviews the historical development of cytology and cytogenetics in Arabidopsis, and summarizes recent developments in molecular cytogenetics, with special emphasis on meiotic studies. Despite the small genome and small chromosomes of Arabidopsis, considerable progress has been made in developing appropriate cytogenetical techniques for chromosome analysis. Fluorescence in situ hybridization (FISH) applied to extended meiotic pachytene chromosomes has resulted in a standardized karyotype (idiogram) for the species that has also been aligned with the genetical map. A better understanding of floral and meiotic development has been achieved by combining cytological studies, based on both sectioning and spreading techniques, with morphometric data and developmental landmarks. The meiotic interphase, preceding prophase I, has been investigated by marking the nuclei undergoing DNA replication with BrdU. This allowed the subclasses of meiotic interphase to be distinguished and also provided a means to time the duration of meiosis and its constituent phases. The FISH technique has been used to analyse in detail the meiotic organization of telomeres and centromeric regions. The results indicate that centromere regions do not play an active role in chromosome pairing and synapsis; however, telomeres pair homologously in advance of general chromosome synapsis. The FISH technique is currently being applied to analysing the pairing and synapsis of interstitial chromosome regions through interphase and prophase I. FISH probes also allow the five bivalents of Arabidopsis to be identified at metaphase I and this has permitted an analysis of chiasma frequencies in individual bivalents, both in wild-type Arabidopsis and in two meiotic mutants.

Targeted tandem duplication of a large chromosomal segment in Aspergillus oryzae.

PubMed

Takahashi, Tadashi; Sato, Atsushi; Ogawa, Masahiro; Hanya, Yoshiki; Oguma, Tetsuya

2014-08-01

We describe here the first successful construction of a targeted tandem duplication of a large chromosomal segment in Aspergillus oryzae. The targeted tandem chromosomal duplication was achieved by using strains that had a 5'-deleted pyrG upstream of the region targeted for tandem chromosomal duplication and a 3'-deleted pyrG downstream of the target region. Consequently,strains bearing a 210-kb targeted tandem chromosomal duplication near the centromeric region of chromosome 8 and strains bearing a targeted tandem chromosomal duplication of a 700-kb region of chromosome 2 were successfully constructed. The strains bearing the tandem chromosomal duplication were efficiently obtained from the regenerated protoplast of the parental strains. However, the generation of the chromosomal duplication did not depend on the introduction of double-stranded breaks(DSBs) by I-SceI. The chromosomal duplications of these strains were stably maintained after five generations of culture under nonselective conditions. The strains bearing the tandem chromosomal duplication in the 700-kb region of chromosome 2 showed highly increased protease activity in solid-state culture, indicating that the duplication of large chromosomal segments could be a useful new breeding technology and gene analysis method.

Myeloid- and lymphoid-specific breakpoint cluster regions in chromosome band 13q14 in acute leukemia.

PubMed

Coignet, L J; Lima, C S; Min, T; Streubel, B; Swansbury, J; Telford, N; Swanton, S; Bowen, A; Nagai, M; Catovsky, D; Fonatsch, C; Dyer, M J

1999-07-01

Abnormalities of chromosome band 13q14 occur in hematologic malignancies of all lineages and at all stages of differentiation. Unlike other chromosomal translocations, which are usually specific for a given lineage, the chromosomal translocation t(12;13)(p12;q14) has been observed in both B-cell and T-cell precursor acute lymphoblastic leukemia (BCP-, TCP-ALL), in differentiated and undifferentiated acute myeloblastic leukemia (AML), and in chronic myeloid leukemia (CML) at progression to blast crisis. The nature of these translocations and their pathologic consequences remain unknown. To begin to define the gene(s) involved on chromosome 13, we have performed fluorescence in situ hybridization (FISH) using a panel of YACs from the region, on a series of 10 cases of acute leukemia with t(12;13)(p12;q14) and 1 case each with "variant" translocations including t(12;13)(q21;q14), t(10;13)(q24;q14) and t(9;13)(p21;q14). In 8/13 cases/cell lines, the 13q14 break fell within a single 1.4 Mb CEPH MegaYAC. This YAC fell immediately telomeric of the forkhead (FKHR) gene, which is disrupted in the t(2;13)(q35;q14) seen in pediatric alveolar rhabdomyosarcoma. Seven of the 8 cases with breaks in this YAC were AML. In 4/13 cases, the 13q14 break fell within a 1.7-Mb YAC located about 3 Mb telomeric of the retinoblastoma (RB1) gene: all 4 cases were ALL. One case of myelodysplastic syndrome exhibited a break within 13q12, adjacent to the BRCA2 gene. These data indicate the presence of myeloid- and lymphoid-specific breakpoint cluster regions within chromosome band 13q14 in acute leukemia.

Broad chromosomal domains of histone modification patterns in C. elegans

PubMed Central

Liu, Tao; Rechtsteiner, Andreas; Egelhofer, Thea A.; Vielle, Anne; Latorre, Isabel; Cheung, Ming-Sin; Ercan, Sevinc; Ikegami, Kohta; Jensen, Morten; Kolasinska-Zwierz, Paulina; Rosenbaum, Heidi; Shin, Hyunjin; Taing, Scott; Takasaki, Teruaki; Iniguez, A. Leonardo; Desai, Arshad; Dernburg, Abby F.; Kimura, Hiroshi; Lieb, Jason D.; Ahringer, Julie; Strome, Susan; Liu, X. Shirley

2011-01-01

Chromatin immunoprecipitation identifies specific interactions between genomic DNA and proteins, advancing our understanding of gene-level and chromosome-level regulation. Based on chromatin immunoprecipitation experiments using validated antibodies, we define the genome-wide distributions of 19 histone modifications, one histone variant, and eight chromatin-associated proteins in Caenorhabditis elegans embryos and L3 larvae. Cluster analysis identified five groups of chromatin marks with shared features: Two groups correlate with gene repression, two with gene activation, and one with the X chromosome. The X chromosome displays numerous unique properties, including enrichment of monomethylated H4K20 and H3K27, which correlate with the different repressive mechanisms that operate in somatic tissues and germ cells, respectively. The data also revealed striking differences in chromatin composition between the autosomes and between chromosome arms and centers. Chromosomes I and III are globally enriched for marks of active genes, consistent with containing more highly expressed genes, compared to chromosomes II, IV, and especially V. Consistent with the absence of cytological heterochromatin and the holocentric nature of C. elegans chromosomes, markers of heterochromatin such as H3K9 methylation are not concentrated at a single region on each chromosome. Instead, H3K9 methylation is enriched on chromosome arms, coincident with zones of elevated meiotic recombination. Active genes in chromosome arms and centers have very similar histone mark distributions, suggesting that active domains in the arms are interspersed with heterochromatin-like structure. These data, which confirm and extend previous studies, allow for in-depth analysis of the organization and deployment of the C. elegans genome during development. PMID:21177964

Analysis and visualization of chromosomal abnormalities in SNP data with SNPscan

PubMed Central

Ting, Jason C; Ye, Ying; Thomas, George H; Ruczinski, Ingo; Pevsner, Jonathan

2006-01-01

Background A variety of diseases are caused by chromosomal abnormalities such as aneuploidies (having an abnormal number of chromosomes), microdeletions, microduplications, and uniparental disomy. High density single nucleotide polymorphism (SNP) microarrays provide information on chromosomal copy number changes, as well as genotype (heterozygosity and homozygosity). SNP array studies generate multiple types of data for each SNP site, some with more than 100,000 SNPs represented on each array. The identification of different classes of anomalies within SNP data has been challenging. Results We have developed SNPscan, a web-accessible tool to analyze and visualize high density SNP data. It enables researchers (1) to visually and quantitatively assess the quality of user-generated SNP data relative to a benchmark data set derived from a control population, (2) to display SNP intensity and allelic call data in order to detect chromosomal copy number anomalies (duplications and deletions), (3) to display uniparental isodisomy based on loss of heterozygosity (LOH) across genomic regions, (4) to compare paired samples (e.g. tumor and normal), and (5) to generate a file type for viewing SNP data in the University of California, Santa Cruz (UCSC) Human Genome Browser. SNPscan accepts data exported from Affymetrix Copy Number Analysis Tool as its input. We validated SNPscan using data generated from patients with known deletions, duplications, and uniparental disomy. We also inspected previously generated SNP data from 90 apparently normal individuals from the Centre d'Étude du Polymorphisme Humain (CEPH) collection, and identified three cases of uniparental isodisomy, four females having an apparently mosaic X chromosome, two mislabelled SNP data sets, and one microdeletion on chromosome 2 with mosaicism from an apparently normal female. These previously unrecognized abnormalities were all detected using SNPscan. The microdeletion was independently confirmed by

Mapping the pericentric heterochromatin by comparative genomic hybridization analysis and chromosome deletions in Drosophila melanogaster

PubMed Central

He, Bing; Caudy, Amy; Parsons, Lance; Rosebrock, Adam; Pane, Attilio; Raj, Sandeep; Wieschaus, Eric

2012-01-01

Heterochromatin represents a significant portion of eukaryotic genomes and has essential structural and regulatory functions. Its molecular organization is largely unknown due to difficulties in sequencing through and assembling repetitive sequences enriched in the heterochromatin. Here we developed a novel strategy using chromosomal rearrangements and embryonic phenotypes to position unmapped Drosophila melanogaster heterochromatic sequence to specific chromosomal regions. By excluding sequences that can be mapped to the assembled euchromatic arms, we identified sequences that are specific to heterochromatin and used them to design heterochromatin specific probes (“H-probes”) for microarray. By comparative genomic hybridization (CGH) analyses of embryos deficient for each chromosome or chromosome arm, we were able to map most of our H-probes to specific chromosome arms. We also positioned sequences mapped to the second and X chromosomes to finer intervals by analyzing smaller deletions with breakpoints in heterochromatin. Using this approach, we were able to map >40% (13.9 Mb) of the previously unmapped heterochromatin sequences assembled by the whole-genome sequencing effort on arm U and arm Uextra to specific locations. We also identified and mapped 110 kb of novel heterochromatic sequences. Subsequent analyses revealed that sequences located within different heterochromatic regions have distinct properties, such as sequence composition, degree of repetitiveness, and level of underreplication in polytenized tissues. Surprisingly, although heterochromatin is generally considered to be transcriptionally silent, we detected region-specific temporal patterns of transcription in heterochromatin during oogenesis and early embryonic development. Our study provides a useful approach to elucidate the molecular organization and function of heterochromatin and reveals region-specific variation of heterochromatin. PMID:22745230

Molecular cytogenetics characterization of seven small supernumerary marker chromosomes derived from chromosome 19: Genotype-phenotype correlation and review of the literature.

PubMed

Recalcati, Maria Paola; Bonati, Maria Teresa; Beltrami, Nicola; Cardarelli, Laura; Catusi, Ilaria; Costa, Asia; Garzo, Maria; Mammi, Isabella; Mattina, Teresa; Nalesso, Elisa; Nardone, Anna Maria; Postorivo, Diana; Sajeva, Anna; Varricchio, Aminta; Verri, Annapia; Villa, Nicoletta; Larizza, Lidia; Giardino, Daniela

2018-03-01

Only a few subjects carrying supernumerary marker chromosomes derived from 19 chromosome (sSMC(19)) have been described to date and for a small portion of them the genic content has been defined at the molecular level. We present seven new different sSMCs(19) identified in eight individuals, seven of whom unrelated. The presence of the sSMC is associated with a clinical phenotype in five subjects, while the other three carriers, two of whom related, are normal. All sSMCs(19) have been characterized by means of conventional and molecular cytogenetics. We compare the sSMCs(19) carriers with a clinical phenotype to already described patients with gains (sSMCs or microduplications) of overlapping genomic regions with the aim to deepen the pathogenicity of the encountered imbalances and to assess the role of the involved genes on the phenotype. The present work supports the correlation between the gain of some chromosome 19 critical regions and specific phenotypes. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Copy number variations at the Prader-Willi syndrome region on chromosome 15 and associations with obesity in whites.

PubMed

Chen, Yuan; Liu, Yong-Jun; Pei, Yu-Fang; Yang, Tie-Lin; Deng, Fei-Yan; Liu, Xiao-Gang; Li, Ding-You; Deng, Hong-Wen

2011-06-01

Obesity is a serious health problem with strong genetic determination. Copy number variation (CNV) is a common type of genomic variant associated with some complex human diseases. However, it is not clear how CNVs contribute to the etiology of obesity. In this study, we examined 1,000 unrelated US whites to search for CNVs that may predispose to obesity. We focused our analyses on the Prader-Willi syndrome (PWS) critical region (chromosome 15q11-q13), because the PWS region is a hotspot for CNV generation and obesity is one of the major clinical manifestations for chromosome abnormalities at this region. We constructed a map containing 39 CNVs at the PWS critical region with CNV occurrence rates higher than 1%. Among them, three CNVs were significantly associated with body fat mass (P < 0.05), with a higher copy number (CN) associated with an increase of 5.08-9.77 kg in body fat mass. These three CNVs are close to two known PWS genes, NDN (necdin homolog) and C15orf2 (chromosome 15 open reading frame 2), and partially overlap with another obesity gene PWRN1 (Prader-Willi region nonprotein-coding RNA 1). Interestingly, our recently published whole genome association scan study using the same sample by examining single-nucleotide polymorphisms (SNPs) did not find any significant associations at these CNV regions, suggesting the importance of examining both CNVs and SNPs for better understanding of genetic basis of obesity. Further studies are warranted to validate these CNVs and their importance to obesity.

Delineation by fluorescence in situ hybridization of a single hemizygous chromosomal region associated with aposporous embryo sac formation in Pennisetum squamulatum and Cenchrus ciliaris.

PubMed Central

Goel, Shailendra; Chen, Zhenbang; Conner, Joann A; Akiyama, Yukio; Hanna, Wayne W; Ozias-Akins, Peggy

2003-01-01

Apomixis is a means of asexual reproduction by which plants produce embryos without meiosis and fertilization; thus the embryo is of clonal, maternal origin. We previously reported molecular markers showing no recombination with the trait for aposporous embryo sac development in Pennisetum squamulatum and Cenchrus ciliaris, and the collective single-dose alleles defined an apospory-specific genomic region (ASGR). Fluorescence in situ hybridization (FISH) was used to confirm that the ASGR is a hemizygous genomic region and to determine its chromosomal position with respect to rDNA loci and centromere repeats. We also documented chromosome transmission from P. squamulatum in several backcrosses (BCs) with P. glaucum using genomic in situ hybridization (GISH). One to three complete P. squamulatum chromosomes were detected in BC(6), but only one of the three hybridized with the ASGR-linked markers. In P. squamulatum and in all BCs examined, the apospory-linked markers were located in the distal region of the short arm of a single chromosome. All alien chromosomes behaved as univalents during meiosis and segregated randomly in BC(3) and later BC generations, but presence of the ASGR-carrier chromosome alone was sufficient to confer apospory. FISH results support our hypotheses that hemizygosity, proximity to centromeric sequences, and chromosome structure may all play a role in low recombination in the ASGR. PMID:12663545

Characterizing the chromosomes of the platypus (Ornithorhynchus anatinus).

PubMed

McMillan, Daniel; Miethke, Pat; Alsop, Amber E; Rens, Willem; O'Brien, Patricia; Trifonov, Vladimir; Veyrunes, Frederic; Schatzkamer, Kyriena; Kremitzki, Colin L; Graves, Tina; Warren, Wesley; Grützner, Frank; Ferguson-Smith, Malcolm A; Graves, Jennifer A Marshall

2007-01-01

Like the unique platypus itself, the platypus genome is extraordinary because of its complex sex chromosome system, and is controversial because of difficulties in identification of small autosomes and sex chromosomes. A 6-fold shotgun sequence of the platypus genome is now available and is being assembled with the help of physical mapping. It is therefore essential to characterize the chromosomes and resolve the ambiguities and inconsistencies in identifying autosomes and sex chromosomes. We have used chromosome paints and DAPI banding to identify and classify pairs of autosomes and sex chromosomes. We have established an agreed nomenclature and identified anchor BAC clones for each chromosome that will ensure unambiguous gene localizations.

Interchromosomal Duplications on the Bactrocera oleae Y Chromosome Imply a Distinct Evolutionary Origin of the Sex Chromosomes Compared to Drosophila

PubMed Central

Gabrieli, Paolo; Gomulski, Ludvik M.; Bonomi, Angelica; Siciliano, Paolo; Scolari, Francesca; Franz, Gerald; Jessup, Andrew; Malacrida, Anna R.; Gasperi, Giuliano

2011-01-01

Background Diptera have an extraordinary variety of sex determination mechanisms, and Drosophila melanogaster is the paradigm for this group. However, the Drosophila sex determination pathway is only partially conserved and the family Tephritidae affords an interesting example. The tephritid Y chromosome is postulated to be necessary to determine male development. Characterization of Y sequences, apart from elucidating the nature of the male determining factor, is also important to understand the evolutionary history of sex chromosomes within the Tephritidae. We studied the Y sequences from the olive fly, Bactrocera oleae. Its Y chromosome is minute and highly heterochromatic, and displays high heteromorphism with the X chromosome. Methodology/Principal Findings A combined Representational Difference Analysis (RDA) and fluorescence in-situ hybridization (FISH) approach was used to investigate the Y chromosome to derive information on its sequence content. The Y chromosome is strewn with repetitive DNA sequences, the majority of which are also interdispersed in the pericentromeric regions of the autosomes. The Y chromosome appears to have accumulated small and large repetitive interchromosomal duplications. The large interchromosomal duplications harbour an importin-4-like gene fragment. Apart from these importin-4-like sequences, the other Y repetitive sequences are not shared with the X chromosome, suggesting molecular differentiation of these two chromosomes. Moreover, as the identified Y sequences were not detected on the Y chromosomes of closely related tephritids, we can infer divergence in the repetitive nature of their sequence contents. Conclusions/Significance The identification of Y-linked sequences may tell us much about the repetitive nature, the origin and the evolution of Y chromosomes. We hypothesize how these repetitive sequences accumulated and were maintained on the Y chromosome during its evolutionary history. Our data reinforce the idea that the

Origin of the chromosomal radiation of Madeiran house mice: a microsatellite analysis of metacentric chromosomes

PubMed Central

Förster, D W; Mathias, M L; Britton-Davidian, J; Searle, J B

2013-01-01

Chromosome races of Mus musculus domesticus are characterised by particular sets of metacentric chromosomes formed by Robertsonian fusions and whole-arm reciprocal translocations. The Atlantic island of Madeira is inhabited by six chromosome races of house mice with 6–9 pairs of metacentric chromosomes. Three of these races are characterised by the metacentric 3.8 also found elsewhere in the distribution of M. m. domesticus, including Denmark and Spain. We investigated the possibility that metacentric 3.8 was introduced to Madeira during the initial colonisation, as this could have ‘seeded' the cascade of chromosomal mutation that is the basis of the extraordinary chromosomal radiation observed on the island. Variation at 24 microsatellite loci mapping to three different chromosomal regions (proximal, interstitial and distal) of mouse chromosomes 3 and 8 was investigated in 179 mice from Madeira, Denmark, Portugal, Spain, Italy and Scotland. Analyses of microsatellite loci closely linked to the centromeres of these chromosomes (‘proximal loci') do not support a common evolutionary origin of metacentric 3.8 among Madeiran, Danish and Spanish mouse populations. Our results suggest that Madeiran mice are genetically more similar to standard karyotype mice from Portugal than to metacentric mice from elsewhere. There is expected to be an interruption to gene flow between hybridising metacentric races on Madeira, particularly in the chromosomal regions close to the rearrangement breakpoints. Consistent with this, relating to differentiation involving chromosomes 3 and 8 on Madeira, we found greater genetic structure among races for proximal than interstitial or distal loci. PMID:23232832

Evidence of linkage and association on chromosome 20 for late-onset Alzheimer disease.

PubMed

Goddard, Katrina A B; Olson, Jane M; Payami, Haydeh; van der Voet, Monique; Kuivaniemi, Helena; Tromp, Gerard

2004-06-01

Recently, we reported evidence of linkage on chromosome 20 for Alzheimer disease (AD) using a novel statistical approach to incorporate covariates (e.g., age, ApoE genotype) into the analysis. These results suggest that very elderly subjects (>85 years), and individuals who carry an epsilon2 allele at the ApoE locus are more likely to be linked to this candidate region. The region on chromosome 20 includes a strong candidate gene, cystatin C (CST3), which has previously been associated with AD in case-control studies. We investigated these findings further by genotyping additional markers to narrow the candidate region, and to identify evidence of linkage disequilibrium as additional support for a susceptibility locus on chromosome 20. We selected 43 elderly sibships (89 subjects) from the NIMH AD Genetics Initiative based on current age older than 84 years, and identified 129 unrelated control subjects who were older than 84 years from the Oregon Brain Aging Study to conduct linkage and association studies in this region. Fourteen additional markers were evaluated, including 4 markers located within or near CST3. We narrowed the candidate region on chromosome 20 to an 11.8-cM region between markers D20S174 and D20S471, which includes the CST3 candidate gene. In addition, we observed evidence of association for markers located near the CST3 candidate gene, with P values between 0.002 and 0.08 for two-locus haplotypes. These results support the presence of a susceptibility locus for AD in the vicinity of CST3 for very elderly subjects with AD.

Analysis of Parent-of-Origin Effects on the X Chromosome in Asian and European Orofacial Cleft Triads Identifies Associations with DMD, FGF13, EGFL6, and Additional Loci at Xp22.2.

PubMed

Skare, Øivind; Lie, Rolv T; Haaland, Øystein A; Gjerdevik, Miriam; Romanowska, Julia; Gjessing, Håkon K; Jugessur, Astanand

2018-01-01

Background: Although both the mother's and father's alleles are present in the offspring, they may not operate at the same level. These parent-of-origin (PoO) effects have not yet been explored on the X chromosome, which motivated us to develop new methods for detecting such effects. Orofacial clefts (OFCs) exhibit sex-specific differences in prevalence and are examples of traits where a search for various types of effects on the X chromosome might be relevant. Materials and Methods: We upgraded our R-package Haplin to enable genome-wide analyses of PoO effects, as well as power simulations for different statistical models. 14,486 X-chromosome SNPs in 1,291 Asian and 1,118 European case-parent triads of isolated OFCs were available from a previous GWAS. For each ethnicity, cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO) were analyzed separately using two X-inactivation models and a sliding-window approach to haplotype analysis. In addition, we performed analyses restricted to female offspring. Results: Associations were identified in "Dystrophin" ( DMD , Xp21.2-p21.1), "Fibroblast growth factor 13" ( FGF13 , Xq26.3-q27.1) and "EGF-like domain multiple 6" ( EGFL6 , Xp22.2), with biologically plausible links to OFCs. Unlike EGFL6 , the other associations on chromosomal region Xp22.2 had no apparent connections to OFCs. However, the Xp22.2 region itself is of potential interest because it contains genes for clefting syndromes [for example, "Oral-facial-digital syndrome 1" ( OFD1 ) and "Midline 1" ( MID1 )]. Overall, the identified associations were highly specific for ethnicity, cleft subtype and X-inactivation model, except for DMD in which associations were identified in both CPO and CL/P, in the model with X-inactivation and in Europeans only. Discussion/Conclusion: The specificity of the associations for ethnicity, cleft subtype and X-inactivation model underscores the utility of conducting subanalyses, despite the ensuing need to adjust

Chromosomal organization of four classes of repetitive DNA sequences in killifish Orestias ascotanensis Parenti, 1984 (Cyprinodontiformes, Cyprinodontidae)

PubMed Central

Araya-Jaime, Cristian; Lam, Natalia; Pinto, Irma Vila; Méndez, Marco A.; Iturra, Patricia

2017-01-01

Abstract Orestias Valenciennes, 1839 is a genus of freshwater fish endemic to the South American Altiplano. Cytogenetic studies of these species have focused on conventional karyotyping. The aim of this study was to use classical and molecular cytogenetic methods to identify the constitutive heterochromatin distribution and chromosome organization of four classes of repetitive DNA sequences (histone H3 DNA, U2 snRNA, 18S rDNA and 5S rDNA) in the chromosomes of O. ascotanensis Parenti, 1984, an endemic species restricted to the Salar de Ascotán in the Chilean Altiplano. All individuals analyzed had a diploid number of 48 chromosomes. C-banding identified constitutive heterochromatin mainly in the pericentromeric region of most chromosomes, especially a GC-rich heterochromatic block of the short arm of pair 3. FISH assay with an 18S probe confirmed the location of the NOR in pair 3 and revealed that the minor rDNA cluster occurs interstitially on the long arm of pair 2. Dual FISH identified a single block of U2 snDNA sequences in the pericentromeric regions of a subtelocentric chromosome pair, while histone H3 sites were observed as small signals scattered in throughout the all chromosomes. This work represents the first effort to document the physical organization of the repetitive fraction of the Orestias genome. These data will improve our understanding of the chromosomal evolution of a genus facing serious conservation problems. PMID:29093798

Fine-mapping of a marbling trait to a 2.9-cM region on bovine chromosome 7 in Japanese Black cattle.

PubMed

Hirano, T; Watanabe, T; Inoue, K; Sugimoto, Y

2008-02-01

To locate quantitative trait loci (QTL) for intramuscular fat deposition (marbling) in a local population of Japanese Black cattle, we performed a genome scan using a paternal half-sib family of Bull A. A marbling QTL was mapped in the region flanked by DIK0079 (20.7 cM) and TGLA303 (39.3 cM) on bovine chromosome (BTA) 7, affecting 5.0% of the total family variance. Haplotype analysis of the QTL region revealed that the marbling-increasing Q allele was transmitted from the dam. On the other hand, Bull B, a maternal half-sib of Bull A, did not receive the Q allele from its dam, based on the following findings: (i) a marbling QTL on BTA7 was not detected in the Bull B paternal half-sib family; (ii) recombination between DIK0079 (20.7 cM) and RM006 (25.4 cM) in the QTL region was observed in the maternal chromosome of Bull B; and (iii) the Q-harbouring steers from Bull A exhibited significantly higher marbling than the steers from Bull B and the remaining steers from Bull A. To precisely compare the maternal chromosomes of both bulls, we constructed a bacterial artificial chromosome contig covering the region between DIK0079 and RM006 and developed DNA markers. The recombination occurred between DIK8042 and DIK8044, indicating that the marbling QTL was in a 2.9-cM region flanked by DIK0079 and DIK8044.

Origin and domestication of papaya Yh chromosome

USDA-ARS?s Scientific Manuscript database

Sex in papaya is controlled by a pair of nascent sex chromosomes. Females are XX, and two slightly different Y chromosomes distinguish males (XY) and hermaphrodites (XYh). The hermaphrodite-specific region of the Yh chromosome (HSY) and its X chromosome counterpart were sequenced and analyzed previo...

Partial deletions of the W chromosome due to reciprocal translocation in the silkworm Bombyx mori.

PubMed

Abe, H; Seki, M; Ohbayashi, F; Tanaka, N; Yamashita, J; Fujii, T; Yokoyama, T; Takahashi, M; Banno, Y; Sahara, K; Yoshido, A; Ihara, J; Yasukochi, Y; Mita, K; Ajimura, M; Suzuki, M G; Oshiki, T; Shimada, T

2005-08-01

In the silkworm, Bombyx mori (female, ZW; male, ZZ), femaleness is determined by the presence of a single W chromosome, irrespective of the number of autosomes or Z chromosomes. The W chromosome is devoid of functional genes, except the putative female-determining gene (Fem). However, there are strains in which chromosomal fragments containing autosomal markers have been translocated on to W. In this study, we analysed the W chromosomal regions of the Zebra-W strain (T(W;3)Ze chromosome) and the Black-egg-W strain (T(W;10)+(w-2) chromosome) at the molecular level. Initially, we undertook a project to identify W-specific RAPD markers, in addition to the three already established W-specific RAPD markers (W-Kabuki, W-Samurai and W-Kamikaze). Following the screening of 3648 arbitrary 10-mer primers, we obtained nine W-specific RAPD marker sequences (W-Bonsai, W-Mikan, W-Musashi, W-Rikishi, W-Sakura, W-Sasuke, W-Yukemuri-L, W-Yukemuri-S and BMC1-Kabuki), almost all of which contained the border regions of retrotransposons, namely portions of nested retrotransposons. We confirmed the presence of eleven out of twelve W-specific RAPD markers in the normal W chromosomes of twenty-five silkworm strains maintained in Japan. These results indicate that the W chromosomes of the strains in Japan are almost identical in type. The Zebra-W strain (T(W;3)Ze chromosome) lacked the W-Samurai and W-Mikan RAPD markers and the Black-egg-W strain (T(W;10)+(w-2) chromosome) lacked the W-Mikan RAPD marker. These results strongly indicate that the regions containing the W-Samurai and W-Mikan RAPD markers or the W-Mikan RAPD marker were deleted in the T(W;3)Ze and T(W;10)+(w-2) chromosomes, respectively, due to reciprocal translocation between the W chromosome and the autosome. This deletion apparently does not affect the expression of Fem; therefore, this deleted region of the W chromosome does not contain the putative Fem gene.

Meiotic synapsis of homogeneously staining regions (HSRs) in chromosome 1 of Mus musculus.

PubMed

Winking, H; Reuter, C; Traut, W

1993-05-01

About 50 copies of a long-range repeat DNA family with a repeat size of roughly 100 kb and with sequence homology to mRNAs are clustered in the G-light band D of chromosome 1 of the house mouse, Mus musculus. We studied amplified versions of the cluster which are found in many wild populations of M. musculus. They are cytogenetically conspicuous as one or two C-band positive homogeneously staining regions (single- and double band HSRs) which increase the mitotic length of chromosome 1. The double band HSR was phylogenetically derived from a single band HSR by a paracentric inversion. In homozygous condition, such HSRs contribute, albeit not as much as expected from their mitotic length, to the synaptonemal complex (SC) length of chromosome 1. In HSR heterozygous animals an elongation of the SCs was not noticeable. In single band HSR heterozygous males, synapsis proceeds regularly and continuously from the distal telomere towards the centromeric end without forming buckles. Thus, the single band HSR has no adverse effect on pairing. The same straight pairing behaviour was found in the majority of double band HSR heterozygous spermatocytes. This shows that extensive nonhomologous pairing can take place in the earliest phase of synapsis. Synapsis was discontinuous, leaving the central part of the bivalent 1 asynapsed, in only 14.3% of double band HSR heterozygous cells. In such cells the chromosome 1 SC is completed at a later stage of meiosis. The delay is presumably an effect of the inversion that includes one HSR band and the segment between the two HSR bands.

A 15 Mb large paracentric chromosome 21 inversion identified in Czech population through a pair of flanking duplications.

PubMed

Drabova, Jana; Trkova, Marie; Hancarova, Miroslava; Novotna, Drahuse; Hejtmankova, Michaela; Havlovicova, Marketa; Sedlacek, Zdenek

2014-01-01

Inversions are balanced structural chromosome rearrangements, which can influence gene expression and the risk of unbalanced chromosome constitution in offspring. Many examples of inversion polymorphisms exist in human, affecting both heterochromatic regions and euchromatin. We describe a novel, 15 Mb long paracentric inversion, inv(21)(q21.1q22.11), affecting more than a third of human 21q. Despite of its length, the inversion cannot be detected using karyotyping due to similar band patterns on the normal and inverted chromosomes, and is therefore likely to escape attention. Its identification was aided by the repeated observation of the same pair of 150 kb long duplications present in cis on chromosome 21 in three Czech families subjected to microarray analysis. The finding prompted us to hypothesise that this co-occurrence of two remote duplications could be associated with an inversion of the intervening segment, and this speculation turned out to be right. The inversion was confirmed in a series of FISH experiments which also showed that the second copy of each of the duplications was always located at the opposite end of the inversion. The presence of the same pair of duplications in additional individuals reported in public databases indicates that the inversion may also be present in other populations. Three out of the total of about 4000 chromosomes 21 examined in our sample carried the duplications and were inverted, corresponding to carrier frequency of about 1/660. Although the breakpoints affect protein-coding genes, the occurrence of the inversion in normal parents and siblings of our patients and the occurrence of the duplications in unaffected controls in databases indicate that this rare variant is rather non-pathogenic. The inverted segment carried an identical shared haplotype in the three families studied. The haplotypes, however, diverged very rapidly in the flanking regions, possibly pointing to an ancient founder event at the origin of the

Fragile sites, dysfunctional telomere and chromosome fusions: What is 5S rDNA role?

PubMed

Barros, Alain Victor; Wolski, Michele Andressa Vier; Nogaroto, Viviane; Almeida, Mara Cristina; Moreira-Filho, Orlando; Vicari, Marcelo Ricardo

2017-04-15

Repetitive DNA regions are known as fragile chromosomal sites which present a high flexibility and low stability. Our focus was characterize fragile sites in 5S rDNA regions. The Ancistrus sp. species shows a diploid number of 50 and an indicative Robertsonian fusion at chromosomal pair 1. Two sequences of 5S rDNA were identified: 5S.1 rDNA and 5S.2 rDNA. The first sequence gathers the necessary structures to gene expression and shows a functional secondary structure prediction. Otherwise, the 5S.2 rDNA sequence does not contain the upstream sequences that are required to expression, furthermore its structure prediction reveals a nonfunctional ribosomal RNA. The chromosomal mapping revealed several 5S.1 and 5S.2 rDNA clusters. In addition, the 5S.2 rDNA clusters were found in acrocentric and metacentric chromosomes proximal regions. The pair 1 5S.2 rDNA cluster is co-located with interstitial telomeric sites (ITS). Our results indicate that its clusters are hotspots to chromosomal breaks. During the meiotic prophase bouquet arrangement, double strand breaks (DSBs) at proximal 5S.2 rDNA of acrocentric chromosomes could lead to homologous and non-homologous repair mechanisms as Robertsonian fusions. Still, ITS sites provides chromosomal instability, resulting in telomeric recombination via TRF2 shelterin protein and a series of breakage-fusion-bridge cycles. Our proposal is that 5S rDNA derived sequences, act as chromosomal fragile sites in association with some chromosomal rearrangements of Loricariidae. Copyright © 2017 Elsevier B.V. All rights reserved.

PanACEA: a bioinformatics tool for the exploration and visualization of bacterial pan-chromosomes.

PubMed

Clarke, Thomas H; Brinkac, Lauren M; Inman, Jason M; Sutton, Granger; Fouts, Derrick E

2018-06-27

Bacterial pan-genomes, comprised of conserved and variable genes across multiple sequenced bacterial genomes, allow for identification of genomic regions that are phylogenetically discriminating or functionally important. Pan-genomes consist of large amounts of data, which can restrict researchers ability to locate and analyze these regions. Multiple software packages are available to visualize pan-genomes, but currently their ability to address these concerns are limited by using only pre-computed data sets, prioritizing core over variable gene clusters, or by not accounting for pan-chromosome positioning in the viewer. We introduce PanACEA (Pan-genome Atlas with Chromosome Explorer and Analyzer), which utilizes locally-computed interactive web-pages to view ordered pan-genome data. It consists of multi-tiered, hierarchical display pages that extend from pan-chromosomes to both core and variable regions to single genes. Regions and genes are functionally annotated to allow for rapid searching and visual identification of regions of interest with the option that user-supplied genomic phylogenies and metadata can be incorporated. PanACEA's memory and time requirements are within the capacities of standard laptops. The capability of PanACEA as a research tool is demonstrated by highlighting a variable region important in differentiating strains of Enterobacter hormaechei. PanACEA can rapidly translate the results of pan-chromosome programs into an intuitive and interactive visual representation. It will empower researchers to visually explore and identify regions of the pan-chromosome that are most biologically interesting, and to obtain publication quality images of these regions.

Development of a quantitative pachytene chromosome map and its unification with somatic chromosome and linkage maps of rice (Oryza sativa L.).

PubMed

Ohmido, Nobuko; Iwata, Aiko; Kato, Seiji; Wako, Toshiyuki; Fukui, Kiichi

2018-01-01

A quantitative pachytene chromosome map of rice (Oryza sativa L.) was developed using imaging methods. The map depicts not only distribution patterns of chromomeres specific to pachytene chromosomes, but also the higher order information of chromosomal structures, such as heterochromatin (condensed regions), euchromatin (decondensed regions), the primary constrictions (centromeres), and the secondary constriction (nucleolar organizing regions, NOR). These features were image analyzed and quantitatively mapped onto the map by Chromosome Image Analyzing System ver. 4.0 (CHIAS IV). Correlation between H3K9me2, an epigenetic marker and formation and/or maintenance of heterochromatin, thus was, clearly visualized. Then the pachytene chromosome map was unified with the existing somatic chromosome and linkage maps by physically mapping common DNA markers among them, such as a rice A genome specific tandem repeat sequence (TrsA), 5S and 45S ribosomal RNA genes, five bacterial artificial chromosome (BAC) clones, four P1 bacteriophage artificial chromosome (PAC) clones using multicolor fluorescence in situ hybridization (FISH). Detailed comparison between the locations of the DNA probes on the pachytene chromosomes using multicolor FISH, and the linkage map enabled determination of the chromosome number and short/long arms of individual pachytene chromosomes using the chromosome number and arm assignment designated for the linkage map. As a result, the quantitative pachytene chromosome map was unified with two other major rice chromosome maps representing somatic prometaphase chromosomes and genetic linkages. In conclusion, the unification of the three rice maps serves as an indispensable basic information, not only for an in-depth comparison between genetic and chromosomal data, but also for practical breeding programs.

The Karyotype of Microsternarchus aff. bilineatus: A First Case of Y Chromosome Degeneration in Gymnotiformes.

PubMed

Batista, Jéssica Almeida; Cardoso, Adauto Lima; Milhomem-Paixão, Susana Suely Rodrigues; Ready, Jonathan Stuart; Pieczarka, Julio Cesar; Nagamachi, Cleusa Yoshiko

2017-06-01

Various species and lineages that until recently were identified as Microsternarchus bilineatus (Hypopomidae, Gymnotiformes) have a widespread distribution in the Amazon and Orinoco River basins and across the Guiana shield. Recent molecular studies show five distinct lineages for Microsternarchus from different localities. These results suggest that this previously monotypic genus actually consists of more than one species. Here, we describe the karyotype of M. aff. bilineatus from the Cururutuia River (Bragança, Pará, Brazil). The diploid number of 48 chromosomes (14 meta-submetacentric/34 subtelo-acrocentric) is found for males and females, with an XX/XY sex chromosome system. The nucleolar organizer region is found in the short arm of pair 9. Constitutive heterochromatin occurs in the pericentromeric region of all chromosomes, in the distal region of 3p, 5p, 7p, 8q, 9q, 16q, and Xq, in the interstitial region in 2p, 10q, 11q, and 12q and all along 4p, and in a large block of the Y chromosome. These results indicate extensive karyotype divergence between this population and samples from Igarapé Tarumã Grande (Negro River, Amazonas, Brazil) studied by other researchers. Moreover, despite the diversity of sex chromosome systems found in Gymnotiformes, the XX/XY sex chromosome system of M. aff. bilineatus is the first case of Y chromosome degeneration in this order. The present data are valuable to help understand karyotype evolution in Hypopomidae.

Identification of human chromosome 22 transcribed sequences with ORF expressed sequence tags

PubMed Central

de Souza, Sandro J.; Camargo, Anamaria A.; Briones, Marcelo R. S.; Costa, Fernando F.; Nagai, Maria Aparecida; Verjovski-Almeida, Sergio; Zago, Marco A.; Andrade, Luis Eduardo C.; Carrer, Helaine; El-Dorry, Hamza F. A.; Espreafico, Enilza M.; Habr-Gama, Angelita; Giannella-Neto, Daniel; Goldman, Gustavo H.; Gruber, Arthur; Hackel, Christine; Kimura, Edna T.; Maciel, Rui M. B.; Marie, Suely K. N.; Martins, Elizabeth A. L.; Nóbrega, Marina P.; Paçó-Larson, Maria Luisa; Pardini, Maria Inês M. C.; Pereira, Gonçalo G.; Pesquero, João Bosco; Rodrigues, Vanderlei; Rogatto, Silvia R.; da Silva, Ismael D. C. G.; Sogayar, Mari C.; de Fátima Sonati, Maria; Tajara, Eloiza H.; Valentini, Sandro R.; Acencio, Marcio; Alberto, Fernando L.; Amaral, Maria Elisabete J.; Aneas, Ivy; Bengtson, Mário Henrique; Carraro, Dirce M.; Carvalho, Alex F.; Carvalho, Lúcia Helena; Cerutti, Janete M.; Corrêa, Maria Lucia C.; Costa, Maria Cristina R.; Curcio, Cyntia; Gushiken, Tsieko; Ho, Paulo L.; Kimura, Elza; Leite, Luciana C. C.; Maia, Gustavo; Majumder, Paromita; Marins, Mozart; Matsukuma, Adriana; Melo, Analy S. A.; Mestriner, Carlos Alberto; Miracca, Elisabete C.; Miranda, Daniela C.; Nascimento, Ana Lucia T. O.; Nóbrega, Francisco G.; Ojopi, Élida P. B.; Pandolfi, José Rodrigo C.; Pessoa, Luciana Gilbert; Rahal, Paula; Rainho, Claudia A.; da Ro's, Nancy; de Sá, Renata G.; Sales, Magaly M.; da Silva, Neusa P.; Silva, Tereza C.; da Silva, Wilson; Simão, Daniel F.; Sousa, Josane F.; Stecconi, Daniella; Tsukumo, Fernando; Valente, Valéria; Zalcberg, Heloisa; Brentani, Ricardo R.; Reis, Luis F. L.; Dias-Neto, Emmanuel; Simpson, Andrew J. G.

2000-01-01

Transcribed sequences in the human genome can be identified with confidence only by alignment with sequences derived from cDNAs synthesized from naturally occurring mRNAs. We constructed a set of 250,000 cDNAs that represent partial expressed gene sequences and that are biased toward the central coding regions of the resulting transcripts. They are termed ORF expressed sequence tags (ORESTES). The 250,000 ORESTES were assembled into 81,429 contigs. Of these, 1,181 (1.45%) were found to match sequences in chromosome 22 with at least one ORESTES contig for 162 (65.6%) of the 247 known genes, for 67 (44.6%) of the 150 related genes, and for 45 of the 148 (30.4%) EST-predicted genes on this chromosome. Using a set of stringent criteria to validate our sequences, we identified a further 219 previously unannotated transcribed sequences on chromosome 22. Of these, 171 were in fact also defined by EST or full length cDNA sequences available in GenBank but not utilized in the initial annotation of the first human chromosome sequence. Thus despite representing less than 15% of all expressed human sequences in the public databases at the time of the present analysis, ORESTES sequences defined 48 transcribed sequences on chromosome 22 not defined by other sequences. All of the transcribed sequences defined by ORESTES coincided with DNA regions predicted as encoding exons by genscan. (http://genes.mit.edu/GENSCAN.html). PMID:11070084

Analysis of X chromosome genomic DNA sequence copy number variation associated with premature ovarian failure (POF)

PubMed Central

Quilter, C.R.; Karcanias, A.C.; Bagga, M.R.; Duncan, S.; Murray, A.; Conway, G.S.; Sargent, C.A.; Affara, N.A.

2013-01-01

BACKGROUND Premature ovarian failure (POF) is a heterogeneous disease defined as amenorrhoea for >6 months before age 40, with an FSH serum level >40 mIU/ml (menopausal levels). While there is a strong genetic association with POF, familial studies have also indicated that idiopathic POF may also be genetically linked. Conventional cytogenetic analyses have identified regions of the X chromosome that are strongly associated with ovarian function, as well as several POF candidate genes. Cryptic chromosome abnormalities that have been missed might be detected by array comparative genomic hybridization. METHODS In this study, samples from 42 idiopathic POF patients were subjected to a complete end-to-end X/Y chromosome tiling path array to achieve a detailed copy number variation (CNV) analysis of X chromosome involvement in POF. The arrays also contained a 1 Mb autosomal tiling path as a reference control. Quantitative PCR for selected genes contained within the CNVs was used to confirm the majority of the changes detected. The expression pattern of some of these genes in human tissue RNA was examined by reverse transcription (RT)–PCR. RESULTS A number of CNVs were identified on both Xp and Xq, with several being shared among the POF cases. Some CNVs fall within known polymorphic CNV regions, and others span previously identified POF candidate regions and genes. CONCLUSIONS The new data reported in this study reveal further discrete X chromosome intervals not previously associated with the disease and therefore implicate new clusters of candidate genes. Further studies will be required to elucidate their involvement in POF. PMID:20570974

Comparative mapping identifies the fusion point of an ancient mammalian X-autosomal rearrangement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilcox, S.A.; Watson, J.M.; Spencer, J.A.

1996-07-01

Previous comparisons of gene location in the three major groups of mammals (eutherians, marsupials, and monotremes) have suggested that the long arm of the human X represents the ancestral mammalian X chromosome, whereas the short arm represents an autosomal region(s) recently added to the eutherian X chromosome. To identify the fusion point of this ancient X-autosome rearrangement, we have mapped four genes, three of which map near the centromere of the human Xp, in marsupials and in a monotreme. We found that ARAF1, and GATA1 are located on the X chromosome in marsupials, and ALA2 and GATA1 are also locatedmore » on the X in the platypus. This implies that the proximal short arm of the human X chromosome, including the centromere, was part of the ancestral mammalian X chromosome. The fusion point between the conserved region and the recently added regions therefore maps to human Xp11.23, although gene order on the human X indicates that there has been some rearrangement of this region. 26 refs., 3 figs., 1 tab.« less

The 5S rDNA in two Abracris grasshoppers (Ommatolampidinae: Acrididae): molecular and chromosomal organization.

PubMed

Bueno, Danilo; Palacios-Gimenez, Octavio Manuel; Martí, Dardo Andrea; Mariguela, Tatiane Casagrande; Cabral-de-Mello, Diogo Cavalcanti

2016-08-01

The 5S ribosomal DNA (rDNA) sequences are subject of dynamic evolution at chromosomal and molecular levels, evolving through concerted and/or birth-and-death fashion. Among grasshoppers, the chromosomal location for this sequence was established for some species, but little molecular information was obtained to infer evolutionary patterns. Here, we integrated data from chromosomal and nucleotide sequence analysis for 5S rDNA in two Abracris species aiming to identify evolutionary dynamics. For both species, two arrays were identified, a larger sequence (named type-I) that consisted of the entire 5S rDNA gene plus NTS (non-transcribed spacer) and a smaller (named type-II) with truncated 5S rDNA gene plus short NTS that was considered a pseudogene. For type-I sequences, the gene corresponding region contained the internal control region and poly-T motif and the NTS presented partial transposable elements. Between the species, nucleotide differences for type-I were noticed, while type-II was identical, suggesting pseudogenization in a common ancestor. At chromosomal point to view, the type-II was placed in one bivalent, while type-I occurred in multiple copies in distinct chromosomes. In Abracris, the evolution of 5S rDNA was apparently influenced by the chromosomal distribution of clusters (single or multiple location), resulting in a mixed mechanism integrating concerted and birth-and-death evolution depending on the unit.

Characterization of the 3p12.3-pcen region associated with tumor suppression in a novel ovarian cancer cell line model genetically modified by chromosome 3 fragment transfer.

PubMed

Cody, Neal A L; Shen, Zhen; Ripeau, Jean-Sebastien; Provencher, Diane M; Mes-Masson, Anne-Marie; Chevrette, Mario; Tonin, Patricia N

2009-12-01

The genetic analysis of nontumorigenic radiation hybrids generated by transfer of chromosome 3 fragments into the tumorigenic OV-90 ovarian cancer cell line identified the 3p12.3-pcen region as a candidate tumor suppressor gene (TSG) locus. In the present study, polymorphic microsatellite repeat analysis of the hybrids further defined the 3p12.3-pcen interval to a 16.1 Mb common region containing 12 known or hypothetical genes: 3ptel-ROBO2-ROBO1-GBE1-CADM2-VGLL3-CHMP2B-POU1F1-HTR1F-CGGBP1-ZNF654-C3orf38-EPHA3-3pcen. Seven of these genes, ROBO1, GBE1, VGLL3, CHMP2B, CGGBP1, ZNF654, and C3orf38, exhibited gene expression in the hybrids, placing them as top TSG candidates for further analysis. The expression of all but one (VGLL3) of these genes was also detected in the parental OV-90 cell line. Mutations were not identified in a comparative sequence analysis of the predicted protein coding regions of these candidates in OV-90 and donor normal chromosome 3 contig. However, the nondeleterious sequence variants identified in the transcribed regions distinguished parent of origin alleles for ROBO1, VGLL3, CHMP2B, and CGGBP1 and cDNA sequencing of the hybrids revealed biallelic expression of these genes. Interestingly, underexpression of VGLL3 and ZNF654 were observed in malignant ovarian tumor samples as compared with primary cultures of normal ovarian surface epithelial cells or benign ovarian tumors, and this occurred regardless of allelic content of 3p12.3-pcen. The results taken together suggest that dysregulation of VGLL3 and/or ZNF654 expression may have affected pathways important in ovarian tumorigenesis which was offset by the transfer of chromosome 3 fragments in OV-90, a cell line hemizygous for 3p.

Evaluation of polymorphisms within the genes GSHR and SLC2A2 that are within a region on bovine chromosome 1 (BTA1) previously associated with feed intake and weight gain

USDA-ARS?s Scientific Manuscript database

Cost of feed is the largest expense incurred by cattle producers. The ability to select for animals with beneficial production traits using genetic markers may reduce expenses for producers. A large region on bovine chromosome 1 was identified as significant for average daily feed intake (ADFI) and ...

Machado Joseph disease maps to the same region of chromosome 14 as the spinocerebellar ataxia type 3 locus.

PubMed Central

Twist, E C; Casaubon, L K; Ruttledge, M H; Rao, V S; Macleod, P M; Radvany, J; Zhao, Z; Rosenberg, R N; Farrer, L A; Rouleau, G A

1995-01-01

Machado Joseph disease (MJD) is an autosomal dominantly inherited neuro-degenerative disorder primarily affecting the motor system. It can be divided into three phenotypes based on the variable combination of a range of clinical symptoms including pyramidal and extra-pyramidal features, cerebellar deficits, and distal muscle atrophy. MJD is thought to be caused by mutation of a single gene which has recently been mapped, using genetic linkage analysis, to a 29 cM region on chromosome 14q24.3-q32 in five Japanese families. A second disorder, spinocerebellar ataxia type 3 (SCA3), which has clinical symptoms similar to MJD, has also been linked to the same region of chromosome 14q in two French families. In order to narrow down the region of chromosome 14 which contains the MJD locus and to determine if this region overlaps with the predisposing locus for SCA3, we have performed genetic linkage analysis in seven MJD families, six of Portuguese/Azorean origin and one of Brazilian origin, using nine microsatellite markers mapped to 14q24.3-q32. Our results localise the MJD locus in these families to an 11 cM interval flanked by the markers D14S68 and AFM343vf1. In addition we show that this 11 cM interval maps within the 15 cM interval containing the SCA3 locus, suggesting that these diseases are allelic. PMID:7897622

Four out of eight genes in a mouse chromosome 7 congenic donor region are candidate obesity genes.

PubMed

Sarahan, Kari A; Fisler, Janis S; Warden, Craig H

2011-09-22

We previously identified a region of mouse chromosome 7 that influences body fat mass in F2 littermates of congenic × background intercrosses. Current analyses revealed that alleles in the donor region of the subcongenic B6.C-D7Mit318 (318) promoted a twofold increase in adiposity in homozygous lines of 318 compared with background C57BL/6ByJ (B6By) mice. Parent-of-origin effects were discounted through cross-fostering studies and an F1 reciprocal cross. Mapping of the donor region revealed that it has a maximal size of 2.8 Mb (minimum 1.8 Mb) and contains a maximum of eight protein coding genes. Quantitative PCR in whole brain, liver, and gonadal white adipose tissue (GWAT) revealed differential expression between genotypes for three genes in females and two genes in males. Alpha-2,8-sialyltransferase 8B (St8sia2) showed reduced 318 mRNA levels in brain for females and males and in GWAT for females only. Both sexes of 318 mice had reduced Repulsive guidance molecule-a (Rgma) expression in GWAT. In brain, Family with sequence similarity 174 member b (Fam174b) had increased expression in 318 females, whereas Chromodomain helicase DNA binding protein 2 (Chd2-2) had reduced expression in 318 males. No donor region genes were differentially expressed in liver. Sequence analysis of coding exons for all genes in the 318 donor region revealed only one single nucleotide polymorphism that produced a nonsynonymous missense mutation, Gln7Pro, in Fam174b. Our findings highlight the difficulty of using expression and sequence to identify quantitative trait genes underlying obesity even in small genomic regions.

Polymer physics of chromosome large-scale 3D organisation

NASA Astrophysics Data System (ADS)

Chiariello, Andrea M.; Annunziatella, Carlo; Bianco, Simona; Esposito, Andrea; Nicodemi, Mario

2016-07-01

Chromosomes have a complex architecture in the cell nucleus, which serves vital functional purposes, yet its structure and folding mechanisms remain still incompletely understood. Here we show that genome-wide chromatin architecture data, as mapped by Hi-C methods across mammalian cell types and chromosomes, are well described by classical scaling concepts of polymer physics, from the sub-Mb to chromosomal scales. Chromatin is a complex mixture of different regions, folded in the conformational classes predicted by polymer thermodynamics. The contact matrix of the Sox9 locus, a region linked to severe human congenital diseases, is derived with high accuracy in mESCs and its molecular determinants identified by the theory; Sox9 self-assembles hierarchically in higher-order domains, involving abundant many-body contacts. Our approach is also applied to the Bmp7 locus. Finally, the model predictions on the effects of mutations on folding are tested against available data on a deletion in the Xist locus. Our results can help progressing new diagnostic tools for diseases linked to chromatin misfolding.

Regional chromosomal localisation of APOA2 to 1q21-1q23.

PubMed

Middleton-Price, H R; van den Berghe, J A; Scott, J; Knott, T J; Malcolm, S

1988-07-01

Using in situ hybridisation, we have mapped APOA2 to the 1q21-1q23 region of chromosome 1. DNA hybridisation to somatic cell hybrids made from cells carrying a balanced translocation between X and 1 confirms the localisation as proximal to 1q23. This was further confirmed by the presence of two polymorphic alleles in a cell line carrying a deletion of 1q25-1q32.

MECHANISMS IN ENDOCRINOLOGY: Aberrations of the X chromosome as cause of male infertility.

PubMed

Röpke, Albrecht; Tüttelmann, Frank

2017-11-01

Male infertility is most commonly caused by spermatogenetic failure, clinically noted as oligo- or a-zoospermia. Today, in approximately 20% of azoospermic patients, a causal genetic defect can be identified. The most frequent genetic causes of azoospermia (or severe oligozoospermia) are Klinefelter syndrome (47,XXY), structural chromosomal abnormalities and Y-chromosomal microdeletions. Consistent with Ohno's law, the human X chromosome is the most stable of all the chromosomes, but contrary to Ohno's law, the X chromosome is loaded with regions of acquired, rapidly evolving genes, which are of special interest because they are predominantly expressed in the testis. Therefore, it is not surprising that the X chromosome, considered as the female counterpart of the male-associated Y chromosome, may actually play an essential role in male infertility and sperm production. This is supported by the recent description of a significantly increased copy number variation (CNV) burden on both sex chromosomes in infertile men and point mutations in X-chromosomal genes responsible for male infertility. Thus, the X chromosome seems to be frequently affected in infertile male patients. Four principal X-chromosomal aberrations have been identified so far: (1) aneuploidy of the X chromosome as found in Klinefelter syndrome (47,XXY or mosaicism for additional X chromosomes). (2) Translocations involving the X chromosome, e.g. nonsyndromic 46,XX testicular disorders of sex development (XX-male syndrome) or X-autosome translocations. (3) CNVs affecting the X chromosome. (4) Point mutations disrupting X-chromosomal genes. All these are reviewed herein and assessed concerning their importance for the clinical routine diagnostic workup of the infertile male as well as their potential to shape research on spermatogenic failure in the next years. © 2017 European Society of Endocrinology.

A novel bacterial blight resistance gene from Oryza nivara mapped to 38 kb region on chromosome 4L and transferred to Oryza sativa L.

PubMed

Cheema, Kuljit K; Grewal, Navjit K; Vikal, Yogesh; Sharma, Rajiv; Lore, Jagjeet S; Das, Aparna; Bhatia, Dharminder; Mahajan, Ritu; Gupta, Vikas; Bharaj, Tajinder S; Singh, Kuldeep

2008-10-01

Bacterial blight (BB) of rice caused by Xanthomonas oryzae pv oryzae (Xoo) is one of the major constraints to productivity in South-East Asia. The strategy of using major genes, singly or in combination, continues to be the most effective approach for BB management. Currently, more than two dozen genes have been designated but not all the known genes are effective against all the prevalent pathotypes. The challenge, therefore, is to continue to expand the gene pool of effective and potentially durable resistance genes. Wild species constitute an important reservoir of the resistance genes including BB. An accession of Oryza nivara (IRGC 81825) was found to be resistant to all the seven Xoo pathotypes prevalent in northern states of India. Inheritance and mapping of resistance in O. nivara was studied by using F2, BC2F2, BC3F1 and BC3F2 progenies of the cross involving Oryza sativa cv PR114 and the O. nivara acc. 81825 using the most virulent Xoo pathotype. Genetic analysis of the segregating progenies revealed that the BB resistance in O. nivara was conditioned by a single dominant gene. Bulked segregant analysis (BSA) of F2 population using 191 polymorphic SSR markers identified a approximately 35 centiMorgans (cM) chromosomal region on 4L, bracketed by RM317 and RM562, to be associated with BB resistance. Screening of BC3F1 and BC2F2 progenies and their genotyping with more than 30 polymorphic SSR markers in the region, covering Bacterial artificial chromosome (BAC) clone OSJNBb0085C12, led to mapping of the resistance gene between the STS markers based on annotated genes LOC_Os04g53060 and LOC_Os04g53120, which is approximately 38.4 kb. Since none of the known Xa genes, which are mapped on chromosome 4L, are effective against the Xoo pathotypes tested, the BB resistance gene identified and transferred from O. nivara is novel and is tentatively designated as Xa30(t). Homozygous resistant BC3F3 progenies with smallest introgression region have been identified.

Isolation of a yeast artificial chromosome contig spanning the Greig cephalopolysyndactyly syndrome (GCPS) gene region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vortkamp, A.; Gessler, M.; Le Paslier, D.

1994-08-01

Disruption of the zinc finger gene GLI3 has been shown to be the cause of Greig cephalopolysyndactyly syndrome (GCPS), at least in some GCPS translocation patients. To characterize this genomic region on human chromosome 7p13, we have isolated a YAC contig of more than 1000 kb including the GLI3 gene. In this contig the gene itself spans at least 200-250 kb. A CpG island is located in the vicinity of the 5{prime} region of the known GLI3 cDNA, implying a potential promoter region. 28 refs., 3 figs., 1 tab.

Vibrio chromosomes share common history.

PubMed

Kirkup, Benjamin C; Chang, LeeAnn; Chang, Sarah; Gevers, Dirk; Polz, Martin F

2010-05-10

While most gamma proteobacteria have a single circular chromosome, Vibrionales have two circular chromosomes. Horizontal gene transfer is common among Vibrios, and in light of this genetic mobility, it is an open question to what extent the two chromosomes themselves share a common history since their formation. Single copy genes from each chromosome (142 genes from chromosome I and 42 genes from chromosome II) were identified from 19 sequenced Vibrionales genomes and their phylogenetic comparison suggests consistent phylogenies for each chromosome. Additionally, study of the gene organization and phylogeny of the respective origins of replication confirmed the shared history. Thus, while elements within the chromosomes may have experienced significant genetic mobility, the backbones share a common history. This allows conclusions based on multilocus sequence analysis (MLSA) for one chromosome to be applied equally to both chromosomes.

Characterization of the human lineage-specific pericentric inversion that distinguishes human chromosome 1 from the homologous chromosomes of the great apes.

PubMed

Szamalek, Justyna M; Goidts, Violaine; Cooper, David N; Hameister, Horst; Kehrer-Sawatzki, Hildegard

2006-08-01

The human and chimpanzee genomes are distinguishable in terms of ten gross karyotypic differences including nine pericentric inversions and a chromosomal fusion. Seven of these large pericentric inversions are chimpanzee-specific whereas two of them, involving human chromosomes 1 and 18, were fixed in the human lineage after the divergence of humans and chimpanzees. We have performed detailed molecular and computational characterization of the breakpoint regions of the human-specific inversion of chromosome 1. FISH analysis and sequence comparisons together revealed that the pericentromeric region of HSA 1 contains numerous segmental duplications that display a high degree of sequence similarity between both chromosomal arms. Detailed analysis of these regions has allowed us to refine the p-arm breakpoint region to a 154.2 kb interval at 1p11.2 and the q-arm breakpoint region to a 562.6 kb interval at 1q21.1. Both breakpoint regions contain human-specific segmental duplications arranged in inverted orientation. We therefore propose that the pericentric inversion of HSA 1 was mediated by intra-chromosomal non-homologous recombination between these highly homologous segmental duplications that had themselves arisen only recently in the human lineage by duplicative transposition.

Sex chromosome abnormalities and psychiatric diseases

PubMed Central

Zhang, Xinzhu; Yang, Jian; Li, Yuhong; Ma, Xin; Li, Rena

2017-01-01

Excesses of sex chromosome abnormalities in patients with psychiatric diseases have recently been observed. It remains unclear whether sex chromosome abnormalities are related to sex differences in some psychiatric diseases. While studies showed evidence of susceptibility loci over many sex chromosomal regions related to various mental diseases, others demonstrated that the sex chromosome aneuploidies may be the key to exploring the pathogenesis of psychiatric disease. In this review, we will outline the current evidence on the interaction of sex chromosome abnormalities with schizophrenia, autism, ADHD and mood disorders. PMID:27992373

Localization and characterization of X chromosome inversion breakpoints separating Drosophila mojavensis and Drosophila arizonae.

PubMed

Cirulli, Elizabeth T; Noor, Mohamed A F

2007-01-01

Ectopic exchange between transposable elements or other repetitive sequences along a chromosome can produce chromosomal inversions. As a result, genome sequence studies typically find sequence similarity between corresponding inversion breakpoint regions. Here, we identify and investigate the breakpoint regions of the X chromosome inversion distinguishing Drosophila mojavensis and Drosophila arizonae. We localize one inversion breakpoint to 13.7 kb and localize the other to a 1-Mb interval. Using this localization and assuming microsynteny between Drosophila melanogaster and D. arizonae, we pinpoint likely positions of the inversion breakpoints to windows of less than 3000 bp. These breakpoints define the size of the inversion to approximately 11 Mb. However, in contrast to many other studies, we fail to find significant sequence similarity between the 2 breakpoint regions. The localization of these inversion breakpoints will facilitate future genetic and molecular evolutionary studies in this species group, an emerging model system for ecological genetics.

Somatic chromosomal engineering identifies BCAN-NTRK1 as a potent glioma driver and therapeutic target.

PubMed

Cook, Peter J; Thomas, Rozario; Kannan, Ram; de Leon, Esther Sanchez; Drilon, Alexander; Rosenblum, Marc K; Scaltriti, Maurizio; Benezra, Robert; Ventura, Andrea

2017-07-11

The widespread application of high-throughput sequencing methods is resulting in the identification of a rapidly growing number of novel gene fusions caused by tumour-specific chromosomal rearrangements, whose oncogenic potential remains unknown. Here we describe a strategy that builds upon recent advances in genome editing and combines ex vivo and in vivo chromosomal engineering to rapidly and effectively interrogate the oncogenic potential of genomic rearrangements identified in human brain cancers. We show that one such rearrangement, an microdeletion resulting in a fusion between Brevican (BCAN) and Neurotrophic Receptor Tyrosine Kinase 1 (NTRK1), is a potent oncogenic driver of high-grade gliomas and confers sensitivity to the experimental TRK inhibitor entrectinib. This work demonstrates that BCAN-NTRK1 is a bona fide human glioma driver and describes a general strategy to define the oncogenic potential of novel glioma-associated genomic rearrangements and to generate accurate preclinical models of this lethal human cancer.

Methods and compositions for chromosome-specific staining

DOEpatents

Gray, Joe W.; Pinkel, Daniel

2003-07-22

Methods and compositions for chromosome-specific staining are provided. Compositions comprise heterogenous mixtures of labeled nucleic acid fragments having substantially complementary base sequences to unique sequence regions of the chromosomal DNA for which their associated staining reagent is specific. Methods include methods for making the chromosome-specific staining compositions of the invention, and methods for applying the staining compositions to chromosomes.

Gene recovery microdissection (GRM) a process for producing chromosome region-specific libraries of expressed genes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christian, A T; Coleman, M A; Tucker, J D

2001-02-08

Gene Recovery Microdissection (GRM) is a unique and cost-effective process for producing chromosome region-specific libraries of expressed genes. It accelerates the pace, reduces the cost, and extends the capabilities of functional genomic research, the means by which scientists will put to life-saving, life-enhancing use their knowledge of any plant or animal genome.

Molecular characterization of Brucella abortus chromosome II recombination.

PubMed

Tsoktouridis, Georgios; Merz, Christian A; Manning, Simon P; Giovagnoli-Kurtz, Renée; Williams, Leanne E; Mujer, Cesar V; Hagius, Sue; Elzer, Philip; Redkar, Rajendra J; Patra, Guy; DelVecchio, Vito G

2003-10-01

Large-scale genomic rearrangements including inversions, deletions, and duplications are significant in bacterial evolution. The recently completed Brucella melitensis 16M and Brucella suis 1330 genomes have facilitated the investigation of such events in the Brucella spp. Suppressive subtractive hybridization (SSH) was employed in identifying genomic differences between B. melitensis 16M and Brucella abortus 2308. Analysis of 45 SSH clones revealed several deletions on chromosomes of B. abortus and B. melitensis that encoded proteins of various metabolic pathways. A 640-kb inversion on chromosome II of B. abortus has been reported previously (S. Michaux Charachon, G. Bourg, E. Jumas Bilak, P. Guigue Talet, A. Allardet Servent, D. O'Callaghan, and M. Ramuz, J. Bacteriol. 179:3244-3249, 1997) and is further described in this study. One end of the inverted region is located on a deleted TATGC site between open reading frames BMEII0292 and BMEII0293. The other end inserted at a GTGTC site of the cyclic-di-GMP phosphodiesterase A (PDEA) gene (BMEII1009), dividing PDEA into two unequal DNA segments of 160 and 977 bp. As a consequence of inversion, the 160-bp segment that encodes the N-terminal region of PDEA was relocated at the opposite end of the inverted chromosomal region. The splitting of the PDEA gene most likely inactivated the function of this enzyme. A recombination mechanism responsible for this inversion is proposed.

Centromere reference models for human chromosomes X and Y satellite arrays

PubMed Central

Miga, Karen H.; Newton, Yulia; Jain, Miten; Altemose, Nicolas; Willard, Huntington F.; Kent, W. James

2014-01-01

The human genome sequence remains incomplete, with multimegabase-sized gaps representing the endogenous centromeres and other heterochromatic regions. Available sequence-based studies within these sites in the genome have demonstrated a role in centromere function and chromosome pairing, necessary to ensure proper chromosome segregation during cell division. A common genomic feature of these regions is the enrichment of long arrays of near-identical tandem repeats, known as satellite DNAs, which offer a limited number of variant sites to differentiate individual repeat copies across millions of bases. This substantial sequence homogeneity challenges available assembly strategies and, as a result, centromeric regions are omitted from ongoing genomic studies. To address this problem, we utilize monomer sequence and ordering information obtained from whole-genome shotgun reads to model two haploid human satellite arrays on chromosomes X and Y, resulting in an initial characterization of 3.83 Mb of centromeric DNA within an individual genome. To further expand the utility of each centromeric reference sequence model, we evaluate sites within the arrays for short-read mappability and chromosome specificity. Because satellite DNAs evolve in a concerted manner, we use these centromeric assemblies to assess the extent of sequence variation among 366 individuals from distinct human populations. We thus identify two satellite array variants in both X and Y centromeres, as determined by array length and sequence composition. This study provides an initial sequence characterization of a regional centromere and establishes a foundation to extend genomic characterization to these sites as well as to other repeat-rich regions within complex genomes. PMID:24501022

Repetitive telomeric sequences in chromosomal translocations involving chromosome 21

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qu, J.; Dallaire, L.; Fetni, R.

Telomeres perform key functions in maintaining chromosome integrity. In some structural rearrangements the structure and polymorphism in human telomeres may play a significant role. However, of all the telomeric and subtelomeric sequences, only the terminal TTAGGG repeats are believed essential for telomere function. During the course of a study on the role of telomere structure and polymorphism in chromosomal rearrangements observed in families referred for prenatal diagnosis, we studied three cases in which chromosome 21 was involved. Repetitive TTAGGG sequences for all human chromosomes were used as probes (Oncor). Case 1, a de novo cryptic translocation (2;21) was initially identifiedmore » as monosomy 21 in a child with psychomotor delay and mild dysmorphism. Using a cosmid probe specific for region 21q22.3 and whole chromosome 21 specific painting probe, the long arm of 21 was found on the short arm of chromosome 2 with an interstitial telomere at the breakpoint junction. All the cells were monosomic for 21pter{yields}q21. Case 2 is a familial (19;21) translocation. GTG-banding and FISH with a satellite probe showed no apparent loss of material at the end of either 19q or 21q, with an interstitial telomere at the fusion site of the two intact chromosomes. In case 3, a four generation reciprocal (20;21) translocation, there was no interstitial telomere. The persistence of an interstitial telomere is a relatively rare event which can now be observed with in situ hybridization. Its study may lead to a better understanding of the dynamics of translocations and of chromosome imbalance.« less

The pig X and Y Chromosomes: structure, sequence, and evolution

PubMed Central

Skinner, Benjamin M.; Sargent, Carole A.; Churcher, Carol; Hunt, Toby; Herrero, Javier; Loveland, Jane E.; Dunn, Matt; Louzada, Sandra; Fu, Beiyuan; Chow, William; Gilbert, James; Austin-Guest, Siobhan; Beal, Kathryn; Carvalho-Silva, Denise; Cheng, William; Gordon, Daria; Grafham, Darren; Hardy, Matt; Harley, Jo; Hauser, Heidi; Howden, Philip; Howe, Kerstin; Lachani, Kim; Ellis, Peter J.I.; Kelly, Daniel; Kerry, Giselle; Kerwin, James; Ng, Bee Ling; Threadgold, Glen; Wileman, Thomas; Wood, Jonathan M.D.; Yang, Fengtang; Harrow, Jen; Affara, Nabeel A.; Tyler-Smith, Chris

2016-01-01

We have generated an improved assembly and gene annotation of the pig X Chromosome, and a first draft assembly of the pig Y Chromosome, by sequencing BAC and fosmid clones from Duroc animals and incorporating information from optical mapping and fiber-FISH. The X Chromosome carries 1033 annotated genes, 690 of which are protein coding. Gene order closely matches that found in primates (including humans) and carnivores (including cats and dogs), which is inferred to be ancestral. Nevertheless, several protein-coding genes present on the human X Chromosome were absent from the pig, and 38 pig-specific X-chromosomal genes were annotated, 22 of which were olfactory receptors. The pig Y-specific Chromosome sequence generated here comprises 30 megabases (Mb). A 15-Mb subset of this sequence was assembled, revealing two clusters of male-specific low copy number genes, separated by an ampliconic region including the HSFY gene family, which together make up most of the short arm. Both clusters contain palindromes with high sequence identity, presumably maintained by gene conversion. Many of the ancestral X-related genes previously reported in at least one mammalian Y Chromosome are represented either as active genes or partial sequences. This sequencing project has allowed us to identify genes—both single copy and amplified—on the pig Y Chromosome, to compare the pig X and Y Chromosomes for homologous sequences, and thereby to reveal mechanisms underlying pig X and Y Chromosome evolution. PMID:26560630

Studies on metatherian sex chromosomes. IX. Sex chromosomes of the greater glider (Marsupialia: Petauridae).

PubMed

Murray, J D; McKay, G M; Sharman, G B

1979-06-01

The greater glider, currently but incorrectly known as Schoinobates volans, is widely distributed in forested regions in eastern Australia. All animals studied from six different localities had 20 autosomes but there were four chromosomally distinct populations. At Royal National Park, N.S.W., all female greater gliders studied had 22 chromosomes including two large submetacentric X chromosomes with subterminal secondary constrictions in their longer arms. This form of X chromosome occurred also at Bondo State Forest, Myall Lakes and Coff's Harbour, N.S.W., and at Eidsvold, Qld. At Coomooboolaroo, Qld, the X chromosome was also a large submetacentric but a secondary constriction occurred in the shorter arm. Two chromosomally distinct types apparently occur in Royal National Park, one with XY males as in all other populations, and one with XY1Y2 males. Y or Y1, but not Y2, chromosomes were eliminated from the bone marrow in all populations but were present in spermatogonia, primary spermatocytes and cultured fibroblasts. Animals from Bondo State Forest had three or more acrocentric or metacentric supernumerary chromosomes.

Chromosomal inactivation of Bacillus subtilis exfusants: a prokaryotic model of epigenetic regulation.

PubMed

Grandjean, V; Hauck, Y; Beloin, C; Le Hégarat, F; Hirschbein, L

1998-01-01

Epigenetic mechanisms are not exclusively reserved to eukaryotic organisms. They are also observed in prokaryotes. As described first by Hotchkiss and Gabor, protoplast fusion between strains of Bacillus subtilis produces heterodiploid cells. Heterodiploidy is associated with the inactivation of one of the chromosomes. To study the physical structure of the fusion product and the molecular mechanisms of inactivation, we constructed heterodiploid clones containing two chromosomes labeled by a NotI restriction fragment length polymorphism. In the progeny, we identified haploid recombinant clones that contain a chromosome carrying large regions of inactivated DNA. Studies of both recombinants of the latter kind and heterodiploid cells indicated that chromosomal inactivation was not determined by alteration of the inactivated nucleotide sequence, but was probably due to a modification in the structure of the bacterial chromatin.

In Silico and Fluorescence In Situ Hybridization Mapping Reveals Collinearity between the Pennisetum squamulatum Apomixis Carrier-Chromosome and Chromosome 2 of Sorghum and Foxtail Millet.

PubMed

Sapkota, Sirjan; Conner, Joann A; Hanna, Wayne W; Simon, Bindu; Fengler, Kevin; Deschamps, Stéphane; Cigan, Mark; Ozias-Akins, Peggy

2016-01-01

Apomixis, or clonal propagation through seed, is a trait identified within multiple species of the grass family (Poaceae). The genetic locus controlling apomixis in Pennisetum squamulatum (syn Cenchrus squamulatus) and Cenchrus ciliaris (syn Pennisetum ciliare, buffelgrass) is the apospory-specific genomic region (ASGR). Previously, the ASGR was shown to be highly conserved but inverted in marker order between P. squamulatum and C. ciliaris based on fluorescence in situ hybridization (FISH) and varied in both karyotype and position of the ASGR on the ASGR-carrier chromosome among other apomictic Cenchrus/Pennisetum species. Using in silico transcript mapping and verification of physical positions of some of the transcripts via FISH, we discovered that the ASGR-carrier chromosome from P. squamulatum is collinear with chromosome 2 of foxtail millet and sorghum outside of the ASGR. The in silico ordering of the ASGR-carrier chromosome markers, previously unmapped in P. squamulatum, allowed for the identification of a backcross line with structural changes to the P. squamulatum ASGR-carrier chromosome derived from gamma irradiated pollen.

In Silico and Fluorescence In Situ Hybridization Mapping Reveals Collinearity between the Pennisetum squamulatum Apomixis Carrier-Chromosome and Chromosome 2 of Sorghum and Foxtail Millet

PubMed Central

Sapkota, Sirjan; Conner, Joann A.; Hanna, Wayne W.; Simon, Bindu; Fengler, Kevin; Deschamps, Stéphane; Cigan, Mark; Ozias-Akins, Peggy

2016-01-01

Apomixis, or clonal propagation through seed, is a trait identified within multiple species of the grass family (Poaceae). The genetic locus controlling apomixis in Pennisetum squamulatum (syn Cenchrus squamulatus) and Cenchrus ciliaris (syn Pennisetum ciliare, buffelgrass) is the apospory-specific genomic region (ASGR). Previously, the ASGR was shown to be highly conserved but inverted in marker order between P. squamulatum and C. ciliaris based on fluorescence in situ hybridization (FISH) and varied in both karyotype and position of the ASGR on the ASGR-carrier chromosome among other apomictic Cenchrus/Pennisetum species. Using in silico transcript mapping and verification of physical positions of some of the transcripts via FISH, we discovered that the ASGR-carrier chromosome from P. squamulatum is collinear with chromosome 2 of foxtail millet and sorghum outside of the ASGR. The in silico ordering of the ASGR-carrier chromosome markers, previously unmapped in P. squamulatum, allowed for the identification of a backcross line with structural changes to the P. squamulatum ASGR-carrier chromosome derived from gamma irradiated pollen. PMID:27031857

Genome structure and primitive sex chromosome revealed in Populus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tuskan, Gerald A; Yin, Tongming; Gunter, Lee E

We constructed a comprehensive genetic map for Populus and ordered 332 Mb of sequence scaffolds along the 19 haploid chromosomes in order to compare chromosomal regions among diverse members of the genus. These efforts lead us to conclude that chromosome XIX in Populus is evolving into a sex chromosome. Consistent segregation distortion in favor of the sub-genera Tacamahaca alleles provided evidence of divergent selection among species, particularly at the proximal end of chromosome XIX. A large microsatellite marker (SSR) cluster was detected in the distorted region even though the genome-wide distribute SSR sites was uniform across the physical map. Themore » differences between the genetic map and physical sequence data suggested recombination suppression was occurring in the distorted region. A gender-determination locus and an overabundance of NBS-LRR genes were also co-located to the distorted region and were put forth as the cause for divergent selection and recombination suppression. This hypothesis was verified by using fine-scale mapping of an integrated scaffold in the vicinity of the gender-determination locus. As such it appears that chromosome XIX in Populus is in the process of evolving from an autosome into a sex chromosome and that NBS-LRR genes may play important role in the chromosomal diversification process in Populus.« less

Numerous Transitions of Sex Chromosomes in Diptera

PubMed Central

Vicoso, Beatriz; Bachtrog, Doris

2015-01-01

Many species groups, including mammals and many insects, determine sex using heteromorphic sex chromosomes. Diptera flies, which include the model Drosophila melanogaster, generally have XY sex chromosomes and a conserved karyotype consisting of six chromosomal arms (five large rods and a small dot), but superficially similar karyotypes may conceal the true extent of sex chromosome variation. Here, we use whole-genome analysis in 37 fly species belonging to 22 different families of Diptera and uncover tremendous hidden diversity in sex chromosome karyotypes among flies. We identify over a dozen different sex chromosome configurations, and the small dot chromosome is repeatedly used as the sex chromosome, which presumably reflects the ancestral karyotype of higher Diptera. However, we identify species with undifferentiated sex chromosomes, others in which a different chromosome replaced the dot as a sex chromosome or in which up to three chromosomal elements became incorporated into the sex chromosomes, and others yet with female heterogamety (ZW sex chromosomes). Transcriptome analysis shows that dosage compensation has evolved multiple times in flies, consistently through up-regulation of the single X in males. However, X chromosomes generally show a deficiency of genes with male-biased expression, possibly reflecting sex-specific selective pressures. These species thus provide a rich resource to study sex chromosome biology in a comparative manner and show that similar selective forces have shaped the unique evolution of sex chromosomes in diverse fly taxa. PMID:25879221

Identification and chromosomal localization of Atm, the mouse homolog of the ataxia-telangiectasia gene.

PubMed

Pecker, I; Avraham, K B; Gilbert, D J; Savitsky, K; Rotman, G; Harnik, R; Fukao, T; Schröck, E; Hirotsune, S; Tagle, D A; Collins, F S; Wynshaw-Boris, A; Ried, T; Copeland, N G; Jenkins, N A; Shiloh, Y; Ziv, Y

1996-07-01

Atm, the mouse homolog of the human ATM gene defective in ataxia-telangiectasia (A-T), has been identified. The entire coding sequence of the Atm transcript was cloned and found to contain an open reading frame encoding a protein of 3066 amino acids with 84% overall identity and 91% similarity to the human ATM protein. Variable levels of expression of Atm were observed in different tissues. Fluorescence in situ hybridization and linkage analysis located the Atm gene on mouse chromosome 9, band 9C, in a region homologous to the ATM region on human chromosome 11q22-q23.

Rapid divergence and expansion of the X chromosome in papaya

PubMed Central

Gschwend, Andrea R.; Yu, Qingyi; Tong, Eric J.; Zeng, Fanchang; Han, Jennifer; VanBuren, Robert; Aryal, Rishi; Charlesworth, Deborah; Moore, Paul H.; Paterson, Andrew H.; Ming, Ray

2012-01-01

X chromosomes have long been thought to conserve the structure and gene content of the ancestral autosome from which the sex chromosomes evolved. We compared the recently evolved papaya sex chromosomes with a homologous autosome of a close relative, the monoecious Vasconcellea monoica, to infer changes since recombination stopped between the papaya sex chromosomes. We sequenced 12 V. monoica bacterial artificial chromosomes, 11 corresponding to the papaya X-specific region, and 1 to a papaya autosomal region. The combined V. monoica X-orthologous sequences are much shorter (1.10 Mb) than the corresponding papaya region (2.56 Mb). Given that the V. monoica genome is 41% larger than that of papaya, this finding suggests considerable expansion of the papaya X; expansion is supported by a higher repetitive sequence content of the X compared with the papaya autosomal sequence. The alignable regions include 27 transcript-encoding sequences, only 6 of which are functional X/V. monoica gene pairs. Sequence divergence from the V. monoica orthologs is almost identical for papaya X and Y alleles; the Carica-Vasconcellea split therefore occurred before the papaya sex chromosomes stopped recombining, making V. monoica a suitable outgroup for inferring changes in papaya sex chromosomes. The papaya X and the hermaphrodite-specific region of the Yh chromosome and V. monoica have all gained and lost genes, including a surprising amount of changes in the X. PMID:22869742

Molecular and clinical characterization of a patient with a chromosome 4p deletion, Wolf-Hirschhorn syndrome, and congenital glaucoma.

PubMed

Finzi, S; Pinto, C F; Wiggs, J L

2001-03-01

Wolf-Hirschhorn syndrome is a developmental disorder associated with hemizygous deletion of the distal short arm of chromosome 4. We have identified a patient affected with Wolf-Hirschhorn syndrome and early onset glaucoma. Five other patients with Wolf-Hirschhorn syndrome and early onset glaucoma or ocular anomalies associated with early onset glaucoma have been previously described, suggesting that the association with Wolf-Hirschhorn syndrome is not coincidental. The infrequent association of early onset glaucoma suggests that the chromosomal region commonly deleted in Wolf-Hirschhorn patients does not contain genes responsible for early onset glaucoma. In this study, we performed a molecular characterization of the deleted chromosome 4 to determine the extent of the deletion in an attempt to begin to identify the chromosomal region responsible for the associated glaucoma. Using microsatellite repeat markers located on 4p, we determined that the deletion spanned a 60-cM region including the minimal Wolf-Hirschhorn region. The proximal breakpoint occurred between markers D4S3045 and D4S2974. These results support the hypothesis that patients with Wolf-Hirschhorn syndrome and early onset glaucoma may have large deletions of 4p that include a gene(s) that may be responsible for a dominant form of congenital glaucoma.

Search for copy number variants in chromosomes 15q11-q13 and 22q11.2 in obsessive compulsive disorder

PubMed Central

2010-01-01

Background Obsessive-compulsive disorder (OCD) is a clinically and etiologically heterogeneous syndrome. The high frequency of obsessive-compulsive symptoms reported in subjects with the 22q11.2 deletion syndrome (DiGeorge/velocardiofacial syndrome) or Prader-Willi syndrome (15q11-13 deletion of the paternally derived chromosome), suggests that gene dosage effects in these chromosomal regions could increase risk for OCD. Therefore, the aim of this study was to search for microrearrangements in these two regions in OCD patients. Methods We screened the 15q11-13 and 22q11.2 chromosomal regions for genomic imbalances in 236 patients with OCD using multiplex ligation-dependent probe amplification (MLPA). Results No deletions or duplications involving 15q11-13 or 22q11.2 were identified in our patients. Conclusions Our results suggest that deletions/duplications of chromosomes 15q11-13 and 22q11.2 are rare in OCD. Despite the negative findings in these two regions, the search for copy number variants in OCD using genome-wide array-based methods is a highly promising approach to identify genes of etiologic importance in the development of OCD. PMID:20565924

Search for copy number variants in chromosomes 15q11-q13 and 22q11.2 in obsessive compulsive disorder.

PubMed

Delorme, Richard; Moreno-De-Luca, Daniel; Gennetier, Aurélie; Maier, Wolfgang; Chaste, Pauline; Mössner, Rainald; Grabe, Hans Jörgen; Ruhrmann, Stephan; Falkai, Peter; Mouren, Marie-Christine; Leboyer, Marion; Wagner, Michael; Betancur, Catalina

2010-06-21

Obsessive-compulsive disorder (OCD) is a clinically and etiologically heterogeneous syndrome. The high frequency of obsessive-compulsive symptoms reported in subjects with the 22q11.2 deletion syndrome (DiGeorge/velocardiofacial syndrome) or Prader-Willi syndrome (15q11-13 deletion of the paternally derived chromosome), suggests that gene dosage effects in these chromosomal regions could increase risk for OCD. Therefore, the aim of this study was to search for microrearrangements in these two regions in OCD patients. We screened the 15q11-13 and 22q11.2 chromosomal regions for genomic imbalances in 236 patients with OCD using multiplex ligation-dependent probe amplification (MLPA). No deletions or duplications involving 15q11-13 or 22q11.2 were identified in our patients. Our results suggest that deletions/duplications of chromosomes 15q11-13 and 22q11.2 are rare in OCD. Despite the negative findings in these two regions, the search for copy number variants in OCD using genome-wide array-based methods is a highly promising approach to identify genes of etiologic importance in the development of OCD.

Reproductive Incompatibility Involving Senegalese Aedes aegypti (L) Is Associated with Chromosome Rearrangements

PubMed Central

Dickson, Laura B.; Sharakhova, Maria V.; Timoshevskiy, Vladimir A.; Fleming, Karen L.; Caspary, Alex; Sylla, Massamba; Black, William C.

2016-01-01

was used to identify AT-rich regions, chromomycin A3 following pretreatment with barium hydroxide stained for GC-rich regions and stained the ribosomal RNA locus and YOYO-1 was used to test for differential staining. Chromosome patterns in SenAae strains revealed by these three stains differed from those in IB12. For FISH, 40 BAC clones previously physically mapped on Aaa chromosomes were used to test for chromosome rearrangements in SenAae relative to IB12. Differences in the order of markers identified two chromosomal rearrangements between IB12 and SenAae strains. The first rearrangement involves two overlapping pericentric (containing the centromere) inversions in chromosome 3 or an insertion of a large fragment into the 3q arm. The second rearrangement is close to the centromere on the p arm of chromosome 2. Linkage analysis of the SDL and the white-eye locus identified a likely chromosomal rearrangement on chromosome 1. The reproductive incompatibility observed within SenAae and between SenAae and Aaa may be generally associated with chromosome rearrangements on all three chromosomes and specifically caused by pericentric inversions on chromosomes 2 and 3. PMID:27105225

Shugoshins: Tension-Sensitive Pericentromeric Adaptors Safeguarding Chromosome Segregation

PubMed Central

2014-01-01

The shugoshin/Mei-S332 family are proteins that associate with the chromosomal region surrounding the centromere (the pericentromere) and that play multiple and distinct roles in ensuring the accuracy of chromosome segregation during both mitosis and meiosis. The underlying role of shugoshins appears to be to serve as pericentromeric adaptor proteins that recruit several different effectors to this region of the chromosome to regulate processes critical for chromosome segregation. Crucially, shugoshins undergo changes in their localization in response to the tension that is exerted on sister chromosomes by the forces of the spindle that will pull them apart. This has led to the idea that shugoshins provide a platform for activities required at the pericentromere only when sister chromosomes lack tension. Conversely, disassembly of the shugoshin pericentromeric platform may provide a signal that sister chromosomes are under tension. Here the functions and regulation of these important tension-sensitive pericentromeric proteins are discussed. PMID:25452306

Regional assignment of seven genes on chromosome 1 of man by use of man-Chinese hamster somatic cell hybrids. I. Results obtained after hybridization of human cells carrying reciprocal translocations involving chromosome 1.

PubMed

Jongsma, A P; Burgerhout, W G

1977-01-01

Regional localization studies of genes coding for human PGD, PPH1, PGM1, UGPP, GuK1, Pep-C, and FH, which have been assigned to chromosome 1, were performed with man-Chinese hamster somatic cell hybrids, Informative hybrids that retained fragments of the human chromosome 1 were produced by fusion of hamster cells with human cells carrying reciprocal translocations involving chromosome 1. Analysis of the hybrids that retained one of the translocation chromosomes or de novo rearrangements involving the human 1 revealed the following gene positions: PGD and PPH1 in 1pter leads to 1p32, PGM1 in 1p32 leads to 1p22, UGPP and GuK1 in 1q21 leads to 1q42, FH in 1qter leads to 1q42, and Pep-C probably in 1q42.

Genome structure and emerging evidence of an incipient sex chromosome in Populus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Tongming; DiFazio, Stephen P; Gunter, Lee E

The genus Populus consists of dioecious woody species with largely unknown genetic mechanisms for gender determination. We have discovered genetic and genomic features in the peritelomeric region of chromosome XIX that suggest this region of the Populus genome is in the process of developing characteristics of a sex chromosome. We have identified a gender-associated locus that consistently maps to this region. Furthermore, comparison of genetic maps across multiple Populus families reveals consistently distorted segregation within this region. We have intensively characterized this region using an F1 interspecific cross involving the female genotype that was used for genome sequencing. This regionmore » shows suppressed recombination and high divergence between the alternate haplotypes, as revealed by dense map-based genome assembly using microsatellite markers. The suppressed recombination, distorted segregation, and haplotype divergence were observed only for the maternal parent in this cross. Furthermore, the progeny of this cross showed a strongly male-biased sex ratio, in agreement with Haldane's rule that postulates that the heterogametic sex is more likely to be absent, rare, or sterile in interspecific crosses. Together, these results support the role of chromosome XIX in sex determination and suggest that sex determination in Populus occurs through a ZW system in which the female is the heterogametic gender.« less

Narrowing the wingless-2 mutation to a 227 kb candidate region on chicken chromosome 12

PubMed Central

Webb, A E; Youngworth, I A; Kaya, M; Gitter, C L; O’Hare, E A; May, B; Cheng, H H; Delany, M E

2018-01-01

ABSTRACT Wingless-2 (wg-2) is an autosomal recessive mutation in chicken that results in an embryonic lethal condition. Affected individuals exhibit a multisystem syndrome characterized by absent wings, truncated legs, and craniofacial, kidney, and feather malformations. Previously, work focused on phenotype description, establishing the autosomal recessive pattern of Mendelian inheritance and placing the mutation on an inbred genetic background to create the congenic line UCD Wingless-2.331. The research described in this paper employed the complementary tools of breeding, genetics, and genomics to map the chromosomal location of the mutation and successively narrow the size of the region for analysis of the causative element. Specifically, the wg-2 mutation was initially mapped to a 7 Mb region of chromosome 12 using an Illumina 3 K SNP array. Subsequent SNP genotyping and exon sequencing combined with analysis from improved genome assemblies narrowed the region of interest to a maximum size of 227 kb. Within this region, 3 validated and 3 predicted candidate genes are found, and these are described. The wg-2 mutation is a valuable resource to contribute to an improved understanding of the developmental pathways involved in chicken and avian limb development as well as serving as a model for human development, as the resulting syndrome shares features with human congenital disorders. PMID:29562287

Abnormally banded chromosomal regions in doxorubicin-resistant B16-BL6 murine melanoma cells.

PubMed

Slovak, M L; Hoeltge, G A; Ganapathi, R

1986-08-01

B16-BL6 murine melanoma cells were selected for cytogenetic evaluation during the stepwise development of increasing resistance in vitro to the antitumor antibiotic, doxorubicin (DOX). Karyotypic studies demonstrated extensive heteroploidy with both numerical and structural abnormalities which were not present in the parental DOX-sensitive B16-BL6 cells. Trypsin-Giemsa banding revealed the presence of several marker chromosomes containing abnormally banding regions (ABRs) in the 44-fold B16-BL6 DOX-resistant subline. These ABRs appeared to be more homogeneously staining at the higher DOX concentrations. Length measurements (ABR index) in seven banded metaphases indicated a direct correlation with increasing DOX concentration. When the DOX-resistant cells were grown in drug-free medium for 1 yr, the drug-resistant phenotype gradually declined in parallel with the level of resistance and the ABR index. DOX-induced cytogenetic damage examined by sister chromatid exchange methodology in parental B16-BL6 cells indicated a linear sister chromatid exchange:DOX dose-response relationship. However, after continuous treatment of parental B16-BL6 cells with DOX (0.01 microgram/ml) for 30 days, sister chromatid exchange scores were found to return to base-line values. The B16-BL6 resistant cells demonstrated a cross-resistant phenotype with N-trifluoroacetyladriamycin-14-valerate, actinomycin D, and the Vinca alkaloids but not with 1-beta-D-arabinofuranosylcytosine. The results suggest that ABR-containing chromosomes in DOX-resistant sublines may represent cytogenetic alterations of specific amplified genes involved in the expression of DOX resistance. Further studies are required to identify and define the possible gene products and to correlate their relationship to the cytotoxic action of doxorubicin.

Sex Chromosome Evolution in Amniotes: Applications for Bacterial Artificial Chromosome Libraries

PubMed Central

Janes, Daniel E.; Valenzuela, Nicole; Ezaz, Tariq; Amemiya, Chris; Edwards, Scott V.

2011-01-01

Variability among sex chromosome pairs in amniotes denotes a dynamic history. Since amniotes diverged from a common ancestor, their sex chromosome pairs and, more broadly, sex-determining mechanisms have changed reversibly and frequently. These changes have been studied and characterized through the use of many tools and experimental approaches but perhaps most effectively through applications for bacterial artificial chromosome (BAC) libraries. Individual BAC clones carry 100–200 kb of sequence from one individual of a target species that can be isolated by screening, mapped onto karyotypes, and sequenced. With these techniques, researchers have identified differences and similarities in sex chromosome content and organization across amniotes and have addressed hypotheses regarding the frequency and direction of past changes. Here, we review studies of sex chromosome evolution in amniotes and the ways in which the field of research has been affected by the advent of BAC libraries. PMID:20981143

Comparative mapping of DNA probes derived from the V{sub k} immunoglobulin gene regions on human and great ape chromosomes by fluorescence in situ hybridization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arnold, N.; Wienberg, J.; Ermert, K.

Fluorescence in situ hybridization (FISH) of cosmid clones of human V{sub K} gene regions to human and primate chromosomes contributed to the dating of chromosome reorganizations in evolution. A clone from the K locus at 2p11-p12 (cos 106) hybridized to the assumed homologous chromosome bands in the chimpanzees Pan troglodytes (PTR) and P. paniscus (PPA), the Gorilla gorilla (GGO), and the orangutan Pongo Pygmaeus (PPY). Human and both chimpanzees differed from gorilla and orangutan by the mapping of cos 170, a clone derived from chromosome 2cen-q11.2; the transposition of this orphon to the other side of the centromere can, therefore,more » be dated after the human/chimpanzee and gorilla divergence. Hybridization to homologous bands was also found with a cosmid clone containing a V{sub K}I orphon located on chromosome 1 (cos 115, main signal at 1q31-q32), although the probe is not fully unique. Also, a clone derived from the orphon V{sub K} region on chromosome 22q11 (cos 121) hybridized to the homologous bands in the great apes. This indicates that the orphons on human chromosomes 1 and 22 had been translocated early in primate evolution. 18 refs., 2 figs.« less

Segment-Wise Genome-Wide Association Analysis Identifies a Candidate Region Associated with Schizophrenia in Three Independent Samples

PubMed Central

Rietschel, Marcella; Mattheisen, Manuel; Breuer, René; Schulze, Thomas G.; Nöthen, Markus M.; Levinson, Douglas; Shi, Jianxin; Gejman, Pablo V.; Cichon, Sven; Ophoff, Roel A.

2012-01-01

Recent studies suggest that variation in complex disorders (e.g., schizophrenia) is explained by a large number of genetic variants with small effect size (Odds Ratio∼1.05–1.1). The statistical power to detect these genetic variants in Genome Wide Association (GWA) studies with large numbers of cases and controls (∼15,000) is still low. As it will be difficult to further increase sample size, we decided to explore an alternative method for analyzing GWA data in a study of schizophrenia, dramatically reducing the number of statistical tests. The underlying hypothesis was that at least some of the genetic variants related to a common outcome are collocated in segments of chromosomes at a wider scale than single genes. Our approach was therefore to study the association between relatively large segments of DNA and disease status. An association test was performed for each SNP and the number of nominally significant tests in a segment was counted. We then performed a permutation-based binomial test to determine whether this region contained significantly more nominally significant SNPs than expected under the null hypothesis of no association, taking linkage into account. Genome Wide Association data of three independent schizophrenia case/control cohorts with European ancestry (Dutch, German, and US) using segments of DNA with variable length (2 to 32 Mbp) was analyzed. Using this approach we identified a region at chromosome 5q23.3-q31.3 (128–160 Mbp) that was significantly enriched with nominally associated SNPs in three independent case-control samples. We conclude that considering relatively wide segments of chromosomes may reveal reliable relationships between the genome and schizophrenia, suggesting novel methodological possibilities as well as raising theoretical questions. PMID:22723893

Complete genomic screen in late-onset familial Alzheimer disease. Evidence for a new locus on chromosome 12.

PubMed

Pericak-Vance, M A; Bass, M P; Yamaoka, L H; Gaskell, P C; Scott, W K; Terwedow, H A; Menold, M M; Conneally, P M; Small, G W; Vance, J M; Saunders, A M; Roses, A D; Haines, J L

1997-10-15

Four genetic loci have been identified as contributing to Alzheimer disease (AD), including the amyloid precursor protein gene, the presenilin 1 gene, the presenilin 2 gene, and the apolipoprotein E gene, but do not account for all the genetic risk for AD. To identify additional genetic risk factors for late-onset AD. A complete genomic screen was performed (N=280 markers). Critical values for chromosomal regional follow-up were a P value of .05 or less for affected relative pair analysis or sibpair analysis, a parametric lod score of 1.0 or greater, or both. Regional follow-up included analysis of additional markers and a second data set. Clinic populations in the continental United States. From a series of multiplex families affected with late-onset (> or =60 years) AD ascertained during the last 14 years (National Insititute of Neurological Disorders and Stroke-Alzheimer's Disease and Related Disorders Association diagnostic criteria) and for which DNA has been obtained, a subset of 16 families (135 total family members, 52 of whom were patients with AD) was used for the genomic screen. A second subset of 38 families (216 total family members, 89 of whom were patients with AD) was used for the follow-up analysis. Linkage analysis results generated using both genetic model-dependent (lod score) and model-independent methods. Fifteen chromosomal regions warranted initial follow-up. Follow-up analyses revealed 4 regions of continued interest on chromosomes 4, 6, 12, and 20, with the strongest results observed forchromosome 12. Peak 2-point affecteds-only lod scores (n=54) were 1.3, 1.6, 2.7, and 2.2 and affected relative pairs P values (n=54) were .04, .03, .14, and .04 for D12S373, D12S1057, D12S1042, and D12S390, respectively. Sibpair analysis (n=54) resulted in maximum lod scores (MLSs) of 1.5, 2.6, 3.2, and 2.3 for these markers, with a peak multipoint MLS of 3.5. A priori stratification by APOE genotype identified 27 families that had at least 1 member with AD

Chronic lymphocytic leukemia-associated chromosomal abnormalities and miRNA deregulation.

PubMed

Kiefer, Yvonne; Schulte, Christoph; Tiemann, Markus; Bullerdiek, Joern

2012-01-01

Chronic lymphocytic leukemia is the most common leukemia in adults. By cytogenetic investigations major subgroups of the disease can be identified that reflect different routes of tumor development. Of these chromosomal deviations, trisomy 12 and deletions of parts of either the long arm of chromosome 13, the long arm of chromosome 11, or the short arm of chromosome 17 are most commonly detected. In some of these aberrations the molecular target has been identified as eg, ataxia telangiectasia mutated (ATM) in case of deletions of chromosomal region 11q22~23 and the genes encoding microRNAs miR-15a/16-1 as likely targets of deletions of chromosomal band 13q14.3. Of note, these aberrations do not characterize independent subgroups but often coexist within the metaphases of one tumor. Generally, complex aberrations are associated with a worse prognosis than simple karyotypic alterations. Due to smaller sizes of the missing segment the detection of recurrent deletions is not always possible by means of classical cytogenetics but requires more advanced techniques as in particular fluorescence in situ hybridization (FISH). Nevertheless, at this time it is not recommended to replace classical cytogenetics by FISH because this would miss additional information given by complex or secondary karyotypic alterations. However, the results of cytogenetic analyses allow the stratification of prognostic and predictive groups of the disease. Of these, the group characterized by deletions involving TP53 is clinically most relevant. In the future refined methods as eg, array-based comparative genomic hybridization will supplement the existing techniques to characterize CLL.

Cre recombinase-mediated site-specific recombination between plant chromosomes.

PubMed Central

Qin, M; Bayley, C; Stockton, T; Ow, D W

1994-01-01

We report the use of the bacteriophage P1 Cre-lox system for generating conservative site-specific recombination between tobacco chromosomes. Two constructs, one containing a promoterless hygromycin-resistance gene preceded by a lox site (lox-hpt) and the other containing a cauliflower mosaic virus 35S promoter linked to a lox sequence and the cre coding region (35S-lox-cre), were introduced separately into tobacco plants. Crosses between plants harboring either construct produced plants with the two constructs situated on different chromosomes. Plants with recombination events were identified by selecting for hygromycin resistance, a phenotype expressed upon recombination. Molecular analysis showed that these recombination events occurred specifically at the lox sites and resulted in the reciprocal exchange of flanking host DNA. Progenies of these plants showed 67-100% cotransmission of the new transgenes, 35S-lox-hpt and lox-cre, consistent with the preferential cosegregation of translocated chromosomes. These results illustrate that site-specific recombination systems can be useful tools for the large-scale manipulation of eukaryotic chromosomes in vivo. Images PMID:8127869

Chromosome jumping from D4S10 (G8) toward the Huntington disease gene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richards, J.E.; Gilliam, T.C.; Cole, J.L.

1988-09-01

The gene for Huntington disease (HD) has been localized to the distal portion of the short arm of human chromosome 4 by linkage analysis. Currently, the two closest DNA markers are D4S10 (G8), located /approx/3 centimorgans centromeric to HD, and D4S43 (C4H), positioned 0-1.5 centimorgans from HD. In an effort to move closer to the HD gene, with the eventual goal of identifying the gene itself, the authors have applied the technique of chromosome jumping to this region. A 200-kilobase jumping library has been constructed, and a jump from D4S10 has been obtained and its approximate distance verified by pulsedmore » field gel electrophoresis. Two restriction fragment length polymorphisms have been identified at the jump locus, which is denoted D4S81. Linkage analysis of previously identified recombinants between D4S10 and HD or D4S10 and D4S43 shows that in two of five events the jump has crossed the recombination points. This unequivocally orients D4S10 and D4S81 on the chromosome, provides additional markers for HD, and suggests that recombination frequency in this region of chromosome 4 may be increased, so that the physical distance from D4S10 to HD may not be as large as originally suspected.« less

Characterisation of the Nevoid basal cell carcinoma (Gorlin`s) syndrome (NBCCS) gene region on chromosome 9q22-q31

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, D.J.; Digweed, M.; Sperling, K.

1994-09-01

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominantly inherited malignancy-associated disease of unknown etiology. The gene has been mapped to chromosome 9q22-q31 by us and other groups, using linkage analysis and loss of heterozygosity studies. Subsequent linkage and haplotype analyses from 133 meioses in NBCCS families has refined the position of the gene between D9S12 and D9S287. Since the gene for Fanconi`s Anaemia type C (FAAC) has been assigned to the same 9q region, we have performed linkage analysis between FACC and NBCCCS in NBCCS families. No recombination has been observed between NBCCS and FACC and maximum lodmore » scores of 34.98 and 11.94 occur for both diseases at the markers D9S196/D9S197. Southern blot analysis using an FACC cDNA probe has revealed no detectable rearrangements in our NBCCS patients. We have established a YAC contig spanning the region from D9S12 to D9S176 and STS content mapping in 22 YACs has allowed the ordering of 12 loci in the region, including the xeroderma pigmentosum type A (XPAC) gene, as follows: D9S151/D9S12P1 - D9S12P2 - D9S197 - D9S196 - D9S280 - FACC - D9S287/XPAC - D9S180 - D9S6 - D9S176. Using the contig we have been able to eliminate the {alpha}1 type XV collagen gene and the markers D9S119 and D9S297 from the NBCCS candidate region. Twelve YACs have been used to screen a chromosome 9 cosmid library and more than 1000 cosmids from the region have been identified to be used for the construction of a cosmid contig. A selection of these cosmids will be used for the isolation of coding sequencing from the region.« less

Telomere healing following DNA polymerase arrest-induced breakages is likely the main mechanism generating chromosome 4p terminal deletions.

PubMed

Hannes, Femke; Van Houdt, Jeroen; Quarrell, Oliver W; Poot, Martin; Hochstenbach, Ron; Fryns, Jean-Pierre; Vermeesch, Joris R

2010-12-01

Constitutional developmental disorders are frequently caused by terminal chromosomal deletions. The mechanisms and/or architectural features that might underlie those chromosome breakages remain largely unexplored. Because telomeres are the vital DNA protein complexes stabilizing linear chromosomes against chromosome degradation, fusion, and incomplete replication, those terminal-deleted chromosomes acquired new telomeres either by telomere healing or by telomere capture. To unravel the mechanisms leading to chromosomal breakage and healing, we sequenced nine chromosome 4p terminal deletion boundaries. A computational analysis of the breakpoint flanking region, including 12 previously published pure terminal breakage sites, was performed in order to identify architectural features that might be involved in this process. All terminal 4p truncations were likely stabilized by telomerase-mediated telomere healing. In the majority of breakpoints multiple genetic elements have a potential to induce secondary structures and an enrichment in replication stalling site motifs were identified. These findings suggest DNA replication stalling-induced chromosome breakage during early development is the first mechanistic step leading toward terminal deletion syndromes. © 2010 Wiley-Liss, Inc.

Exclusion of candidate genes from the chromosome 1q juvenile glaucoma region and mapping of the peripheral cannabis receptor gene (CNR2) to chromosome 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sunden, S.L.F.; Nichols, B.E.; Alward, W.L.M.

Juvenile onset primary open angle glaucoma has been mapped by linkage to 1q21-q31. Several candidate genes were evaluated in the same family used to identify the primary linkage. Atrionatriuretic peptide receptor A (NPR1) and laminin C1 (LAMC1) have been previously mapped to this region and could putatively play a role in the pathogenesis of glaucoma. A third gene, the peripheral cannabis receptor (CNR2) was not initially mapped in humans but was a candidate because of the relief that cannabis affords some patients with primary open angle glaucoma. Microsatellites associated with NPR1 and LAMC1 revealed multiple recombinations in affected members ofmore » this pedigree. CNR2 was shown to be on chromosome 1 by PCR amplification of a 150 bp fragment of the 3{prime} untranslated region in monochromosomal somatic cell hybrids (NIGMS panel No. 2). These primers also revealed a two allele single strand conformation polymorphism which showed multiple recombinants with juvenile onset primary open angle glaucoma in large pedigrees, segregating this disorder. The marker was then mapped to 1p34-p36 by linkage, with the most likely location between liver alkaline phosphatase (ALPL) and alpha-L-1 fucosidase (FUCA1).« less

A novel method for sex determination by detecting the number of X chromosomes.

PubMed

Nakanishi, Hiroaki; Shojo, Hideki; Ohmori, Takeshi; Hara, Masaaki; Takada, Aya; Adachi, Noboru; Saito, Kazuyuki

2015-01-01

A novel method for sex determination, based on the detection of the number of X chromosomes, was established. Current methods, based on the detection of the Y chromosome, can directly identify an unknown sample as male, but female gender is determined indirectly, by not detecting the Y chromosome. Thus, a direct determination of female gender is important because the quality (e.g., fragmentation and amelogenin-Y null allele) of the Y chromosome DNA may lead to a false result. Thus, we developed a novel sex determination method by analyzing the number of X chromosomes using a copy number variation (CNV) detection technique (the comparative Ct method). In this study, we designed a primer set using the amelogenin-X gene without the CNV region as the target to determine the X chromosome copy number, to exclude the influence of the CNV region from the comparative Ct value. The number of X chromosomes was determined statistically using the CopyCaller software with real-time PCR. All DNA samples from participants (20 males, 20 females) were evaluated correctly using this method with 1-ng template DNA. A minimum of 0.2-ng template DNA was found to be necessary for accurate sex determination with this method. When using ultraviolet-irradiated template DNA, as mock forensic samples, the sex of the samples could not be determined by short tandem repeat (STR) analysis but was correctly determined using our method. Thus, we successfully developed a method of sex determination based on the number of X chromosomes. Our novel method will be useful in forensic practice for sex determination.

Painting analysis of chromosome aberrations induced by energetic heavy ions in human cells

NASA Astrophysics Data System (ADS)

Wu, H.; Hada, M.; Cucinotta, F. A.

Energetic heavy ions pose a great health risk to astronauts in extended ISS and future exploration missions High-LET heavy ions are particularly effective in causing various biological effects including cell inactivation genetic mutations and cancer induction Most of these biological endpoints are closely related to chromosomal damage which can be utilized as a biomarker for radiation insults Over the years we have studied chromosomal damage in human fibroblast epithelia and lymphocyte cells exposed in vitro to energetic charged particles generated at several accelerator facilities in the world Various fluorescence in situ hybridization painting techniques have been used to identify from only the telomere region of the chromosome to every chromosome in a human cell We will summarize the results of the investigations and discuss the unique radiation signatures and biomarkers for space radiation exposure

A High-Resolution Comparative Chromosome Map of Cricetus cricetus and Peromyscus eremicus Reveals the Involvement of Constitutive Heterochromatin in Breakpoint Regions.

PubMed

Vieira-da-Silva, Ana; Louzada, Sandra; Adega, Filomena; Chaves, Raquel

2015-01-01

Compared to humans and other mammals, rodent genomes, specifically Muroidea species, underwent intense chromosome reshuffling in which many complex structural rearrangements occurred. This fact makes them preferential animal models for studying the process of karyotype evolution. Here, we present the first combined chromosome comparative maps between 2 Cricetidae species, Cricetus cricetus and Peromyscus eremicus, and the index species Mus musculus and Rattus norvegicus. Comparative chromosome painting was done using mouse and rat paint probes together with in silico analysis from the Ensembl genome browser database. Hereby, evolutionary events (inter- and intrachromosomal rearrangements) that occurred in C. cricetus and P. eremicus since the putative ancestral Muroidea genome could be inferred, and evolutionary breakpoint regions could be detected. A colocalization of constitutive heterochromatin and evolutionary breakpoint regions in each genome was observed. Our results suggest the involvement of constitutive heterochromatin in karyotype restructuring of these species, despite the different levels of conservation of the C. cricetus (derivative) and P. eremicus (conserved) genomes. © 2015 S. Karger AG, Basel.

Molecular Characterization of Brucella abortus Chromosome II Recombination

PubMed Central

Tsoktouridis, Georgios; Merz, Christian A.; Manning, Simon P.; Giovagnoli-Kurtz, Renée; Williams, Leanne E.; Mujer, Cesar V.; Hagius, Sue; Elzer, Philip; Redkar, Rajendra J.; Patra, Guy; DelVecchio, Vito G.

2003-01-01

Large-scale genomic rearrangements including inversions, deletions, and duplications are significant in bacterial evolution. The recently completed Brucella melitensis 16M and Brucella suis 1330 genomes have facilitated the investigation of such events in the Brucella spp. Suppressive subtractive hybridization (SSH) was employed in identifying genomic differences between B. melitensis 16M and Brucella abortus 2308. Analysis of 45 SSH clones revealed several deletions on chromosomes of B. abortus and B. melitensis that encoded proteins of various metabolic pathways. A 640-kb inversion on chromosome II of B. abortus has been reported previously (S. Michaux Charachon, G. Bourg, E. Jumas Bilak, P. Guigue Talet, A. Allardet Servent, D. O'Callaghan, and M. Ramuz, J. Bacteriol. 179:3244-3249, 1997) and is further described in this study. One end of the inverted region is located on a deleted TATGC site between open reading frames BMEII0292 and BMEII0293. The other end inserted at a GTGTC site of the cyclic-di-GMP phosphodiesterase A (PDEA) gene (BMEII1009), dividing PDEA into two unequal DNA segments of 160 and 977 bp. As a consequence of inversion, the 160-bp segment that encodes the N-terminal region of PDEA was relocated at the opposite end of the inverted chromosomal region. The splitting of the PDEA gene most likely inactivated the function of this enzyme. A recombination mechanism responsible for this inversion is proposed. PMID:14526025

In-depth Investigation of Genetic Region Identifies Mechanism that Contributes to Cancer Risk

Cancer.gov

Investigators in the Laboratory of Translational Genomics have identified a genetic variant in a multi-cancer risk locus at chromosome 5p15.33 that explains, at least in part, the molecular mechanism through which this variant influences cancer risk.

A segment of the apospory-specific genomic region is highly microsyntenic not only between the apomicts Pennisetum squamulatum and buffelgrass, but also with a rice chromosome 11 centromeric-proximal genomic region.

PubMed

Gualtieri, Gustavo; Conner, Joann A; Morishige, Daryl T; Moore, L David; Mullet, John E; Ozias-Akins, Peggy

2006-03-01

Bacterial artificial chromosome (BAC) clones from apomicts Pennisetum squamulatum and buffelgrass (Cenchrus ciliaris), isolated with the apospory-specific genomic region (ASGR) marker ugt197, were assembled into contigs that were extended by chromosome walking. Gene-like sequences from contigs were identified by shotgun sequencing and BLAST searches, and used to isolate orthologous rice contigs. Additional gene-like sequences in the apomicts' contigs were identified by bioinformatics using fully sequenced BACs from orthologous rice contigs as templates, as well as by interspecies, whole-contig cross-hybridizations. Hierarchical contig orthology was rapidly assessed by constructing detailed long-range contig molecular maps showing the distribution of gene-like sequences and markers, and searching for microsyntenic patterns of sequence identity and spatial distribution within and across species contigs. We found microsynteny between P. squamulatum and buffelgrass contigs. Importantly, this approach also enabled us to isolate from within the rice (Oryza sativa) genome contig Rice A, which shows the highest microsynteny and is most orthologous to the ugt197-containing C1C buffelgrass contig. Contig Rice A belongs to the rice genome database contig 77 (according to the current September 12, 2003, rice fingerprint contig build) that maps proximal to the chromosome 11 centromere, a feature that interestingly correlates with the mapping of ASGR-linked BACs proximal to the centromere or centromere-like sequences. Thus, relatedness between these two orthologous contigs is supported both by their molecular microstructure and by their centromeric-proximal location. Our discoveries promote the use of a microsynteny-based positional-cloning approach using the rice genome as a template to aid in constructing the ASGR toward the isolation of genes underlying apospory.

Role of DNA secondary structures in fragile site breakage along human chromosome 10

PubMed Central

Dillon, Laura W.; Pierce, Levi C. T.; Ng, Maggie C. Y.; Wang, Yuh-Hwa

2013-01-01

The formation of alternative DNA secondary structures can result in DNA breakage leading to cancer and other diseases. Chromosomal fragile sites, which are regions of the genome that exhibit chromosomal breakage under conditions of mild replication stress, are predicted to form stable DNA secondary structures. DNA breakage at fragile sites is associated with regions that are deleted, amplified or rearranged in cancer. Despite the correlation, unbiased examination of the ability to form secondary structures has not been evaluated in fragile sites. Here, using the Mfold program, we predict potential DNA secondary structure formation on the human chromosome 10 sequence, and utilize this analysis to compare fragile and non-fragile DNA. We found that aphidicolin (APH)-induced common fragile sites contain more sequence segments with potential high secondary structure-forming ability, and these segments clustered more densely than those in non-fragile DNA. Additionally, using a threshold of secondary structure-forming ability, we refined legitimate fragile sites within the cytogenetically defined boundaries, and identified potential fragile regions within non-fragile DNA. In vitro detection of alternative DNA structure formation and a DNA breakage cell assay were used to validate the computational predictions. Many of the regions identified by our analysis coincide with genes mutated in various diseases and regions of copy number alteration in cancer. This study supports the role of DNA secondary structures in common fragile site instability, provides a systematic method for their identification and suggests a mechanism by which DNA secondary structures can lead to human disease. PMID:23297364

[Dandy-walker syndrome and microdeletions on chromosome 7].

PubMed

Liao, Can; Fu, Fang; Li, Ru; Pan, Min; Yang, Xin; Yi, Cui-xing; Li, Jian; Li, Dong-zhi

2012-02-01

To investigate genetic etiology of Dandy-Walker syndrome with array-based comparative genomic hybridization (array-CGH). Eight fetuses with Dandy-Walker malformations but normal karyotypes by conventional cytogenetic technique were selected. DNA samples were extracted and hybridized with Affymetrix cytogenetic 2.7 M arrays by following the manufacturer's standard protocol. The data were analyzed by special software packages. By using array-CGH technique, common deletions and duplication on chromosome 7p21.3 were identified in three cases, within which were central nervous system disease associated genes NDUFA4 and PHF14. Copy number variations (CNVs) of chromosome 7p21.3 region are associated with Dandy-Walker malformations which may be due to haploinsufficiency or overexpression of NDUFA4 and PHF14 genes.

High resolution chromosome 3p, 8p, 9q and 22q allelotyping analysis in the pathogenesis of gallbladder carcinoma

PubMed Central

Wistuba, I I; Maitra, A; Carrasco, R; Tang, M; Troncoso, P; Minna, J D; Gazdar, A F

2002-01-01

Our recent genome-wide allelotyping analysis of gallbladder carcinoma identified 3p, 8p, 9q and 22q as chromosomal regions with frequent loss of heterozygosity. The present study was undertaken to more precisely identify the presence and location of regions of frequent allele loss involving those chromosomes in gallbladder carcinoma. Microdissected tissue from 24 gallbladder carcinoma were analysed for PCR-based loss of heterozygosity using 81 microsatellite markers spanning chromosome 3p (n=26), 8p (n=14), 9q (n=29) and 22q (n=12) regions. We also studied the role of those allele losses in gallbladder carcinoma pathogenesis by examining 45 microdissected normal and dysplastic gallbladder epithelia accompanying gallbladder carcinoma, using 17 microsatellite markers. Overall frequencies of loss of heterozygosity at 3p (100%), 8p (100%), 9q (88%), and 22q (92%) sites were very high in gallbladder carcinoma, and we identified 13 distinct regions undergoing frequent loss of heterozygosity in tumours. Allele losses were frequently detected in normal and dysplastic gallbladder epithelia. There was a progressive increase of the overall loss of heterozygosity frequency with increasing severity of histopathological changes. Allele losses were not random and followed a sequence. This study refines several distinct chromosome 3p, 8p, 9q and 22q regions undergoing frequent allele loss in gallbladder carcinoma that will aid in the positional identification of tumour suppressor genes involved in gallbladder carcinoma pathogenesis. British Journal of Cancer (2002) 87, 432–440. doi:10.1038/sj.bjc.6600490 www.bjcancer.com © 2002 Cancer Research UK PMID:12177780

First description of multivalent ring structures in eutherian mammalian meiosis: new chromosomal characterization of Cormura brevirostris (Emballonuridae, Chiroptera).

PubMed

de Araújo, Ramon Everton Ferreira; Nagamachi, Cleusa Yoshiko; da Costa, Marlyson Jeremias Rodrigues; Noronha, Renata Coelho Rodrigues; Rodrigues, Luís Reginaldo Ribeiro; Pieczarka, Julio César

2016-08-01

Twelve specimens of the bat Cormura brevirostris (Emballonuridae: Chiroptera) were collected from four localities in the Brazilian Amazon region and analyzed by classical and molecular cytogenetics. The diploid number and autosomal fundamental number were as previously reported (2n = 22 and FNa = 40, respectively). Fluorescence in situ hybridization using rDNA probes and silver nitrate technique demonstrated the presence of two NOR sites and the presence of internal telomeric sequences at pericentromeric regions of all chromosomes with exception of Y. Based on meiotic studies and chromosome banding we suggest that the sex chromosome pair of C. brevirostris was equivocally identified as it appears in the literature. Meiotic analysis demonstrated that at diplotene-diakinesis the cells had a ring conformation involving four chromosome pairs. This suggests the occurrence of multiple reciprocal translocations among these chromosomes, which is a very rare phenomenon in vertebrates, and has never been described in Eutheria.

Physical mapping of a large plant genome using global high-information-content-fingerprinting: the distal region of the wheat ancestor Aegilops tauschii chromosome 3DS

PubMed Central

2010-01-01

Background Physical maps employing libraries of bacterial artificial chromosome (BAC) clones are essential for comparative genomics and sequencing of large and repetitive genomes such as those of the hexaploid bread wheat. The diploid ancestor of the D-genome of hexaploid wheat (Triticum aestivum), Aegilops tauschii, is used as a resource for wheat genomics. The barley diploid genome also provides a good model for the Triticeae and T. aestivum since it is only slightly larger than the ancestor wheat D genome. Gene co-linearity between the grasses can be exploited by extrapolating from rice and Brachypodium distachyon to Ae. tauschii or barley, and then to wheat. Results We report the use of Ae. tauschii for the construction of the physical map of a large distal region of chromosome arm 3DS. A physical map of 25.4 Mb was constructed by anchoring BAC clones of Ae. tauschii with 85 EST on the Ae. tauschii and barley genetic maps. The 24 contigs were aligned to the rice and B. distachyon genomic sequences and a high density SNP genetic map of barley. As expected, the mapped region is highly collinear to the orthologous chromosome 1 in rice, chromosome 2 in B. distachyon and chromosome 3H in barley. However, the chromosome scale of the comparative maps presented provides new insights into grass genome organization. The disruptions of the Ae. tauschii-rice and Ae. tauschii-Brachypodium syntenies were identical. We observed chromosomal rearrangements between Ae. tauschii and barley. The comparison of Ae. tauschii physical and genetic maps showed that the recombination rate across the region dropped from 2.19 cM/Mb in the distal region to 0.09 cM/Mb in the proximal region. The size of the gaps between contigs was evaluated by comparing the recombination rate along the map with the local recombination rates calculated on single contigs. Conclusions The physical map reported here is the first physical map using fingerprinting of a complete Triticeae genome. This study

Genomic convergence to identify candidate genes for Alzheimer disease on chromosome 10

PubMed Central

Liang, Xueying; Slifer, Michael; Martin, Eden R.; Schnetz-Boutaud, Nathalie; Bartlett, Jackie; Anderson, Brent; Züchner, Stephan; Gwirtsman, Harry; Gilbert, John R.; Pericak-Vance, Margaret A.; Haines, Jonathan L.

2009-01-01

A broad region of chromosome 10 (chr10) has engendered continued interest in the etiology of late-onset Alzheimer Disease (LOAD) from both linkage and candidate gene studies. However, there is a very extensive heterogeneity on chr10. We converged linkage analysis and gene expression data using the concept of genomic convergence that suggests that genes showing positive results across multiple different data types are more likely to be involved in AD. We identified and examined 28 genes on chr10 for association with AD in a Caucasian case-control dataset of 506 cases and 558 controls with substantial clinical information. The cases were all LOAD (minimum age at onset ≥ 60 years). Both single marker and haplotypic associations were tested in the overall dataset and 8 subsets defined by age, gender, ApoE and clinical status. PTPLA showed allelic, genotypic and haplotypic association in the overall dataset. SORCS1 was significant in the overall data sets (p=0.0025) and most significant in the female subset (allelic association p=0.00002, a 3-locus haplotype had p=0.0005). Odds Ratio of SORCS1 in the female subset was 1.7 (p<0.0001). SORCS1 is an interesting candidate gene involved in the Aβ pathway. Therefore, genetic variations in PTPLA and SORCS1 may be associated and have modest effect to the risk of AD by affecting Aβ pathway. The replication of the effect of these genes in different study populations and search for susceptible variants and functional studies of these genes are necessary to get a better understanding of the roles of the genes in Alzheimer disease. PMID:19241460

Method for obtaining chromosome painting probes

DOEpatents

Lucas, Joe N.

2000-01-01

A method is provided for determining a clastogenic signature of a sample of chromosomes by quantifying a frequency of a first type of chromosome aberration present in the sample; quantifying a frequency of a second, different type of chromosome aberration present in the sample; and comparing the frequency of the first type of chromosome aberration to the frequency of the second type of chromosome aberration. A method is also provided for using that clastogenic signature to identify a clastogenic agent or dosage to which the cells were exposed.

Deletion and duplication within the p11.2 region of chromosome 17

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCorquodale, D.J.; McCorquodale, M.; Bereziouk, O.

1994-09-01

A 7 1/2-year-old male patient presented with mild mental retardation, speech delay, hyperactivity, behavioral problems, mild facial hypoplasia, short broad hands, digital anomalies, and self-injurious behavior. Chromosomes obtained from peripheral blood cells revealed a deletion of 17p11.2 in about 40% of the metaphases examined, suggesting that the patient had Smith-Magenis Syndrome. A similar pattern of mosaicism in peripheral blood cells, but not in fibroblasts in which all cells displayed the deletion, has been previously reported. Since some cases of Smith-Magenis Syndrome have a deletion that extends into the region associated with Charcot-Marie-Tooth (CMT) Syndrome, we examined interphase cells with amore » CMT1A-specific probe by the method of fluorescence in situ hybridization. The CMT1A region was not deleted, but about 40% of the cells gave signals indicating a duplication of the CMT1A region. The patient has not presented neuropathies associated with CMT at this time. Future tracking of the patient should be informative.« less

Lessons learned from the initial sequencing of the pig genome: comparative analysis of an 8 Mb region of pig chromosome 17

PubMed Central

Hart, Elizabeth A; Caccamo, Mario; Harrow, Jennifer L; Humphray, Sean J; Gilbert, James GR; Trevanion, Steve; Hubbard, Tim; Rogers, Jane; Rothschild, Max F

2007-01-01

Background We describe here the sequencing, annotation and comparative analysis of an 8 Mb region of pig chromosome 17, which provides a useful test region to assess coverage and quality for the pig genome sequencing project. We report our findings comparing the annotation of draft sequence assembled at different depths of coverage. Results Within this region we annotated 71 loci, of which 53 are orthologous to human known coding genes. When compared to the syntenic regions in human (20q13.13-q13.33) and mouse (chromosome 2, 167.5 Mb-178.3 Mb), this region was found to be highly conserved with respect to gene order. The most notable difference between the three species is the presence of a large expansion of zinc finger coding genes and pseudogenes on mouse chromosome 2 between Edn3 and Phactr3 that is absent from pig and human. All of our annotation has been made publicly available in the Vertebrate Genome Annotation browser, VEGA. We assessed the impact of coverage on sequence assembly across this region and found, as expected, that increased sequence depth resulted in fewer, longer contigs. One-third of our annotated loci could not be fully re-aligned back to the low coverage version of the sequence, principally because the transcripts are fragmented over several contigs. Conclusion We have demonstrated the considerable advantages of sequencing at increased read depths and discuss the implications that lower coverage sequence may have on subsequent comparative and functional studies, particularly those involving complex loci such as GNAS. PMID:17705864

Analysis of root-knot nematode and fusarium wilt disease resistance in cotton (Gossypium spp.) using chromosome substitution lines from two alien species

USDA-ARS?s Scientific Manuscript database

To Identify a new germplasm resource, and to validate chromosomal regions and favorable alleles associated with nematode and fungal disease resistance traits, a series of interspecific cotton (Gossypium spp.) chromosome substitution (CS) lines were used in this study. The CS lines were developed in ...

Fine mapping and association studies of a high-density lipoprotein cholesterol linkage region on chromosome 16 in French-Canadian subjects

PubMed Central

Dastani, Zari; Pajukanta, Päivi; Marcil, Michel; Rudzicz, Nicholas; Ruel, Isabelle; Bailey, Swneke D; Lee, Jenny C; Lemire, Mathieu; Faith, Janet; Platko, Jill; Rioux, John; Hudson, Thomas J; Gaudet, Daniel; Engert, James C; Genest, Jacques

2010-01-01

Low levels of high-density lipoprotein cholesterol (HDL-C) are an independent risk factor for cardiovascular disease. To identify novel genetic variants that contribute to HDL-C, we performed genome-wide scans and quantitative association studies in two study samples: a Quebec-wide study consisting of 11 multigenerational families and a study of 61 families from the Saguenay–Lac St-Jean (SLSJ) region of Quebec. The heritability of HDL-C in these study samples was 0.73 and 0.49, respectively. Variance components linkage methods identified a LOD score of 2.61 at 98 cM near the marker D16S515 in Quebec-wide families and an LOD score of 2.96 at 86 cM near the marker D16S2624 in SLSJ families. In the Quebec-wide sample, four families showed segregation over a 25.5-cM (18 Mb) region, which was further reduced to 6.6 Mb with additional markers. The coding regions of all genes within this region were sequenced. A missense variant in CHST6 segregated in four families and, with additional families, we observed a P value of 0.015 for this variant. However, an association study of this single-nucleotide polymorphism (SNP) in unrelated Quebec-wide samples was not significant. We also identified an SNP (rs11646677) in the same region, which was significantly associated with a low HDL-C (P=0.016) in the SLSJ study sample. In addition, RT-PCR results from cultured cells showed a significant difference in the expression of CHST6 and KIAA1576, another gene in the region. Our data constitute additional evidence for a locus on chromosome 16q23-24 that affects HDL-C levels in two independent French-Canadian studies. PMID:19844255

Sex Chromosome Turnover Contributes to Genomic Divergence between Incipient Stickleback Species

PubMed Central

Yoshida, Kohta; Makino, Takashi; Yamaguchi, Katsushi; Shigenobu, Shuji; Hasebe, Mitsuyasu; Kawata, Masakado; Kume, Manabu; Mori, Seiichi; Peichel, Catherine L.; Toyoda, Atsushi; Fujiyama, Asao; Kitano, Jun

2014-01-01

Sex chromosomes turn over rapidly in some taxonomic groups, where closely related species have different sex chromosomes. Although there are many examples of sex chromosome turnover, we know little about the functional roles of sex chromosome turnover in phenotypic diversification and genomic evolution. The sympatric pair of Japanese threespine stickleback (Gasterosteus aculeatus) provides an excellent system to address these questions: the Japan Sea species has a neo-sex chromosome system resulting from a fusion between an ancestral Y chromosome and an autosome, while the sympatric Pacific Ocean species has a simple XY sex chromosome system. Furthermore, previous quantitative trait locus (QTL) mapping demonstrated that the Japan Sea neo-X chromosome contributes to phenotypic divergence and reproductive isolation between these sympatric species. To investigate the genomic basis for the accumulation of genes important for speciation on the neo-X chromosome, we conducted whole genome sequencing of males and females of both the Japan Sea and the Pacific Ocean species. No substantial degeneration has yet occurred on the neo-Y chromosome, but the nucleotide sequence of the neo-X and the neo-Y has started to diverge, particularly at regions near the fusion. The neo-sex chromosomes also harbor an excess of genes with sex-biased expression. Furthermore, genes on the neo-X chromosome showed higher non-synonymous substitution rates than autosomal genes in the Japan Sea lineage. Genomic regions of higher sequence divergence between species, genes with divergent expression between species, and QTL for inter-species phenotypic differences were found not only at the regions near the fusion site, but also at other regions along the neo-X chromosome. Neo-sex chromosomes can therefore accumulate substitutions causing species differences even in the absence of substantial neo-Y degeneration. PMID:24625862

X chromosome dosage and presence of SRY shape sex-specific differences in DNA methylation at an autosomal region in human cells.

PubMed

Ho, Bianca; Greenlaw, Keelin; Al Tuwaijri, Abeer; Moussette, Sanny; Martínez, Francisco; Giorgio, Elisa; Brusco, Alfredo; Ferrero, Giovanni Battista; Linhares, Natália D; Valadares, Eugênia R; Svartman, Marta; Kalscheuer, Vera M; Rodríguez Criado, Germán; Laprise, Catherine; Greenwood, Celia M T; Naumova, Anna K

2018-02-20

Sexual dimorphism in DNA methylation levels is a recurrent epigenetic feature in different human cell types and has been implicated in predisposition to disease, such as psychiatric and autoimmune disorders. To elucidate the genetic origins of sex-specific DNA methylation, we examined DNA methylation levels in fibroblast cell lines and blood cells from individuals with different combinations of sex chromosome complements and sex phenotypes focusing on a single autosomal region--the differentially methylated region (DMR) in the promoter of the zona pellucida binding protein 2 (ZPBP2) as a reporter. Our data show that the presence of the sex determining region Y (SRY) was associated with lower methylation levels, whereas higher X chromosome dosage in the absence of SRY led to an increase in DNA methylation levels at the ZPBP2 DMR. We mapped the X-linked modifier of DNA methylation to the long arm of chromosome X (Xq13-q21) and tested the impact of mutations in the ATRX and RLIM genes, located in this region, on methylation levels. Neither ATRX nor RLIM mutations influenced ZPBP2 methylation in female carriers. We conclude that sex-specific methylation differences at the autosomal locus result from interaction between a Y-linked factor SRY and at least one X-linked factor that acts in a dose-dependent manner.

Recurrent sequence exchange between homeologous grass chromosomes.

PubMed

Wicker, Thomas; Wing, Rod A; Schubert, Ingo

2015-11-01

All grass species evolved from an ancestor that underwent a whole-genome duplication (WGD) approximately 70 million years ago. Interestingly, the short arms of rice chromosomes 11 and 12 (and independently their homologs in sorghum) were found to be much more similar to each other than other homeologous regions within the duplicated genome. Based on detailed analysis of rice chromosomes 11 and 12 and their homologs in seven grass species, we propose a mechanism that explains the apparently 'younger' age of the duplication in this region of the genome, assuming a small number of reciprocal translocations at the chromosome termini. In each case the translocations were followed by unbalanced transmission and subsequent lineage sorting of the involved chromosomes to offspring. Molecular dating of these translocation events also allowed us to date major chromosome 'fusions' in the evolutionary lineages that led to Brachypodium and Triticeae. Furthermore, we provide evidence that rice is exceptional regarding the evolution of chromosomes 11 and 12, inasmuch as in other species the process of sequence exchange between homeologous chromosomes ceased much earlier than in rice. We presume that random events rather than selective forces are responsible for the observed high similarity between the short arm ends of rice chromosomes 11 and 12. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Proximity within interphase chromosome contributes to the breakpoint distribution in radiation-induced intrachromosomal exchanges

NASA Astrophysics Data System (ADS)

Zhang, Ye; Uhlemeyer, Jimmy; Hada, Megumi; Asaithamby, A.; Chen, David J.; Wu, Honglu

2014-07-01

Previously, we reported that breaks involved in chromosome aberrations were clustered in several regions of chromosome 3 in human mammary epithelial cells after exposures to either low- or high-LET radiation. In particular, breaks in certain regions of the chromosome tended to rejoin with each other to form an intrachromosome exchange event. This study tests the hypothesis that proximity within a single chromosome in interphase cell nuclei contributes to the distribution of radiation-induced chromosome breaks. Chromosome 3 in G1 human mammary epithelial cells was hybridized with the multicolor banding in situ hybridization (mBAND) probes that distinguish the chromosome in six differently colored regions, and the location of these regions was measured with a laser confocal microscope. Results of the study indicated that, on a multi-mega base pair scale of the DNA, the arrangement of chromatin was non-random. Both telomere regions tended to be located towards the exterior of the chromosome domain, whereas the centromere region towards the interior. In addition, the interior of the chromosome domain was preferentially occupied by the p-arm of the chromatin, which is consistent with our previous finding of intrachromosome exchanges involving breaks on the p-arm and in the centromere region of chromosome 3. Other factors, such as the fragile sites in the 3p21 band and gene regulation, may also contribute to the breakpoint distribution in radiation-induced chromosome aberrations.

Proximity Within Interphase Chromosome Contributes to the Breakpoint Distribution in Radiation-Induced Intrachromosomal Exchanges

NASA Technical Reports Server (NTRS)

Zhang, Ye; Uhlemeyer, Jimmy; Hada, Megumi; Asaithamby, A.; Chen, David J.; Wu, Honglu

2015-01-01

Previously, we reported that breaks involved in chromosome aberrations were clustered in several regions of chromosome3 in human mammary epithelial cells after exposures to either low-or high-LET radiation. In particular, breaks in certain regions of the chromosome tended to rejoin with each other to form an intrachromosome exchange event. This study tests the hypothesis that proximity within a single chromosome in interphase cell nuclei contributes to the distribution of radiation-induced chromosome breaks. Chromosome 3 in G1 human mammary epithelial cells was hybridized with the multicolor banding in situ hybridization (mBAND) probes that distinguish the chromosome in six differently colored regions, and the location of these regions was measured with a laser confocal microscope. Results of the study indicated that, on a multi-mega base pair scale of the DNA, the arrangement of chromatin was non-random. Both telomere regions tended to be located towards the exterior of the chromosome domain, whereas the centromere region towards the interior. In addition, the interior of the chromosome domain was preferentially occupied by the p-arm of the chromatin, which is consistent with our previous finding of intrachromosome exchanges involving breaks on the p-arm and in the centromere region of chromosome3. Other factors, such as the fragile sites in the 3p21 band and gene regulation, may also contribute to the breakpoint distribution in radiation-induced chromosome aberrations. Further investigations suggest that the 3D chromosome folding is cell type and culture condition dependent.

Chromosome Rearrangements in Cornelia de Lange Syndrome (CdLS): Report of a der(3)t(3;12)(p25.3;p13.3) in Two Half Sibs With Features of CdLS and Review of Reported CdLS Cases With Chromosome Rearrangements

PubMed Central

DeScipio, Cheryl; Kaur, Maninder; Yaeger, Dinah; Innis, Jeffrey W.; Spinner, Nancy B.; Jackson, Laird G.; Krantz, Ian D.

2016-01-01

Cornelia de Lange syndrome (CdLS; OMIM 122470) is a dominantly inherited disorder characterized by multisystem involvement, cognitive delay, limb defects, and characteristic facial features. Recently, mutations in NIPBL have been found in ~50% of individuals with CdLS. Numerous chromosomal rearrangements have been reported in individuals with CdLS. These rearrangements may be causative of a CdLS phenotype, result in a phenocopy, or be unrelated to the observed phenotype. We describe two half siblings with a der(3)t(3;12)(p25.3;p13.3) chromosomal rearrangement, clinical features resembling CdLS, and phenotypic overlap with the del(3)(p25) phenotype. Region-specific BAC probes were used to fine-map the breakpoint region by fluorescence in situ hybridization (FISH). FISH analysis places the chromosome 3 breakpoint distal to RP11-115G3 on 3p25.3; the chromosome 12 breakpoint is distal to BAC RP11-88D16 on 12p13.3. A review of published cases of terminal 3p deletions and terminal 12p duplications indicates that the findings in these siblings are consistent with the del(3)(p25) phenotype. Given the phenotypic overlap with CdLS, we have reviewed the reported cases of chromosomal rearrangements involved in CdLS to better elucidate other potential loci that could harbor additional CdLS genes. Additionally, to identify chromosome rearrangements, genome-wide array comparative genomic hybridization (CGH) was performed on eight individuals with typical CdLS and without identifiable deletion or mutation of NIPBL. No pathologic rearrangements were identified. PMID:16075459

The chromosome 2p21 region harbors a complex genetic architecture for association with risk for renal cell carcinoma

PubMed Central

Han, Summer S.; Yeager, Meredith; Moore, Lee E.; Wei, Ming-Hui; Pfeiffer, Ruth; Toure, Ousmane; Purdue, Mark P.; Johansson, Mattias; Scelo, Ghislaine; Chung, Charles C.; Gaborieau, Valerie; Zaridze, David; Schwartz, Kendra; Szeszenia-Dabrowska, Neonilia; Davis, Faith; Bencko, Vladimir; Colt, Joanne S.; Janout, Vladimir; Matveev, Vsevolod; Foretova, Lenka; Mates, Dana; Navratilova, M.; Boffetta, Paolo; Berg, Christine D.; Grubb, Robert L.; Stevens, Victoria L.; Thun, Michael J.; Diver, W. Ryan; Gapstur, Susan M.; Albanes, Demetrius; Weinstein, Stephanie J.; Virtamo, Jarmo; Burdett, Laurie; Brisuda, Antonin; McKay, James D.; Fraumeni, Joseph F.; Chatterjee, Nilanjan; Rosenberg, Philip S.; Rothman, Nathaniel; Brennan, Paul; Chow, Wong-Ho; Tucker, Margaret A.; Chanock, Stephen J.; Toro, Jorge R.

2012-01-01

In follow-up of a recent genome-wide association study (GWAS) that identified a locus in chromosome 2p21 associated with risk for renal cell carcinoma (RCC), we conducted a fine mapping analysis of a 120 kb region that includes EPAS1. We genotyped 59 tagged common single-nucleotide polymorphisms (SNPs) in 2278 RCC and 3719 controls of European background and observed a novel signal for rs9679290 [P = 5.75 × 10−8, per-allele odds ratio (OR) = 1.27, 95% confidence interval (CI): 1.17–1.39]. Imputation of common SNPs surrounding rs9679290 using HapMap 3 and 1000 Genomes data yielded two additional signals, rs4953346 (P = 4.09 × 10−14) and rs12617313 (P = 7.48 × 10−12), both highly correlated with rs9679290 (r2 > 0.95), but interestingly not correlated with the two SNPs reported in the GWAS: rs11894252 and rs7579899 (r2 < 0.1 with rs9679290). Genotype analysis of rs12617313 confirmed an association with RCC risk (P = 1.72 × 10−9, per-allele OR = 1.28, 95% CI: 1.18–1.39) In conclusion, we report that chromosome 2p21 harbors a complex genetic architecture for common RCC risk variants. PMID:22113997

Male infertility associated with de novo pericentric inversion of chromosome 1.

PubMed

Balasar, Özgür; Zamani, Ayşe Gül; Balasar, Mehmet; Acar, Hasan

2017-12-01

Inversion occurs after two breaks in a chromosome have happened and the segment rotates 180° before reinserting. Inversion carriers have produced abnormal gametes if there is an odd number crossing- over between the inverted and the normal homologous chromosomes causing a duplication or deletion. Reproductive risks such as infertility, abortion, stillbirth and birth of malformed child would be expected in that case. A 54-year- old male patient was consulted to our clinic for primary infertility. The routine chromosome study were applied using peripheral blood lymphocyte cultures and analyzed by giemsa-trypsin-giemsa (GTG) banding, and centromer banding (C-banding) stains. Y chromosome microdeletions in the azoospermia factor (AZF) regions were analyzed with polymerase chain reaction. Additional test such as fluorescence in situ hybridization (FISH) was used to detect the sex-determining region of the Y chromosome (SRY). Semen analysis showed azoospermia. A large pericentric inversion of chromosome 1 46,XY, inv(1) (p22q32) was found in routine chromosome analysis. No microdeletions were seen in AZF regions. In our patient the presence of SRY region was observed by using FISH technique with SRY-specific probe. Men who have pericentric inversion of chromosome 1, appear to be at risk for infertility brought about by spermatogenic breakdown. The etiopathogenic relationship between azoospermia and pericentric inversion of chromosome 1 is discussed.

Partial Tetrasomy of Chromosome 22q11.1 Resulting from a Supernumerary Isodicentric Marker Chromosome in a Boy with Cat-eye Syndrome

PubMed Central

Kim, Jun Bum; Pai, Ki Soo; Yun, Jun-No; Park, Sang-Jin

2010-01-01

The 22q11 region has been implicated in chromosomal rearrangements that result in altered gene dosage, leading to three different congenital malformation syndromes: DiGeorge syndrome, cat-eye syndrome (CES), and der(22) syndrome. Although DiGeorge syndrome is a common genomic disorder on 22q11, CES is quite rare, and there has been no report of Korean CES cases with molecular cytogenetic confirmation. In this study, we present the phenotypic and genetic characteristics of a 3-month-old boy with CES. Clinical findings included micropthalmia, multiple colobomata, and renal and genital anomalies. Cytogenetic analyses showed the presence of a supernumerary marker chromosome, which was identified as a bisatellited and isodicentric chromosome derived from an acrocentric chromosome. The results of array comparative genomic hybridization and fluorescence in situ hybridization studies confirmed the karyotype as 47,XY,+mar.ish idic(22)(q11.1) (D22S43+).arr 22q11.1(15,500,000-15,900,000)x4, resulting in a partial tetrasomy of 22q11.1. To the best of our knowledge, this is the first report in Korea of CES confirmed by cytogenetic and molecular cytogenetic analyses. PMID:21165297

Partial tetrasomy of chromosome 22q11.1 resulting from a supernumerary isodicentric marker chromosome in a boy with cat-eye syndrome.

PubMed

Ko, Jung Min; Kim, Jun Bum; Pai, Ki Soo; Yun, Jun-No; Park, Sang-Jin

2010-12-01

The 22q11 region has been implicated in chromosomal rearrangements that result in altered gene dosage, leading to three different congenital malformation syndromes: DiGeorge syndrome, cat-eye syndrome (CES), and der(22) syndrome. Although DiGeorge syndrome is a common genomic disorder on 22q11, CES is quite rare, and there has been no report of Korean CES cases with molecular cytogenetic confirmation. In this study, we present the phenotypic and genetic characteristics of a 3-month-old boy with CES. Clinical findings included micropthalmia, multiple colobomata, and renal and genital anomalies. Cytogenetic analyses showed the presence of a supernumerary marker chromosome, which was identified as a bisatellited and isodicentric chromosome derived from an acrocentric chromosome. The results of array comparative genomic hybridization and fluorescence in situ hybridization studies confirmed the karyotype as 47,XY,+mar.ish idic(22)(q11.1) (D22S43+).arr 22q11.1(15,500,000-15,900,000)x4, resulting in a partial tetrasomy of 22q11.1. To the best of our knowledge, this is the first report in Korea of CES confirmed by cytogenetic and molecular cytogenetic analyses.

Insensitivity of chromosome I and the cell cycle to blockage of replication and segregation of Vibrio cholerae chromosome II.

PubMed

Kadoya, Ryosuke; Chattoraj, Dhruba K

2012-01-01

Vibrio cholerae has two chromosomes (chrI and chrII) whose replication and segregation are under different genetic controls. The region covering the replication origin of chrI resembles that of the Escherichia coli chromosome, and both origins are under control of the highly conserved initiator, DnaA. The origin region of chrII resembles that of plasmids that have iterated initiator-binding sites (iterons) and is under control of the chrII-specific initiator, RctB. Both chrI and chrII encode chromosome-specific orthologs of plasmid partitioning proteins, ParA and ParB. Here, we have interfered with chrII replication, segregation, or both, using extra copies of sites that titrate RctB or ParB. Under these conditions, replication and segregation of chrI remain unaffected for at least 1 cell cycle. In this respect, chrI behaves similarly to the E. coli chromosome when plasmid maintenance is disturbed in the same cell. Apparently, no checkpoint exists to block cell division before the crippled chromosome is lost by a failure to replicate or to segregate. Whether blocking chrI replication can affect chrII replication remains to be tested. Chromosome replication, chromosome segregation, and cell division are the three main events of the cell cycle. They occur in an orderly fashion once per cell cycle. How the sequence of events is controlled is only beginning to be answered in bacteria. The finding of bacteria that possess more than one chromosome raises the important question: how are different chromosomes coordinated in their replication and segregation? It appears that in the evolution of the two-chromosome genome of V. cholerae, either the secondary chromosome adapted to the main chromosome to ensure its maintenance or it is maintained independently, as are bacterial plasmids. An understanding of chromosome coordination is expected to bear on the evolutionary process of chromosome acquisition and on the efficacy of possible strategies for selective elimination of a

Peopling of the North Circumpolar Region--insights from Y chromosome STR and SNP typing of Greenlanders.

PubMed

Olofsson, Jill Katharina; Pereira, Vania; Børsting, Claus; Morling, Niels

2015-01-01

The human population in Greenland is characterized by migration events of Paleo- and Neo-Eskimos, as well as admixture with Europeans. In this study, the Y-chromosomal variation in male Greenlanders was investigated in detail by typing 73 Y-chromosomal single nucleotide polymorphisms (Y-SNPs) and 17 Y-chromosomal short tandem repeats (Y-STRs). Approximately 40% of the analyzed Greenlandic Y chromosomes were of European origin (I-M170, R1a-M513 and R1b-M343). Y chromosomes of European origin were mainly found in individuals from the west and south coasts of Greenland, which is in agreement with the historic records of the geographic placements of European settlements in Greenland. Two Inuit Y-chromosomal lineages, Q-M3 (xM19, M194, L663, SA01 and L766) and Q-NWT01 (xM265) were found in 23% and 31% of the male Greenlanders, respectively. The time to the most recent common ancestor (TMRCA) of the Q-M3 lineage of the Greenlanders was estimated to be between 4,400 and 10,900 years ago (y. a.) using two different methods. This is in agreement with the theory that the North Circumpolar Region was populated via a second expansion of humans in the North American continent. The TMRCA of the Q-NWT01 (xM265) lineage in Greenland was estimated to be between 7,000 and 14,300 y. a. using two different methods, which is older than the previously reported TMRCA of this lineage in other Inuit populations. Our results indicate that Inuit individuals carrying the Q-NWT01 (xM265) lineage may have their origin in the northeastern parts of North America and could be descendants of the Dorset culture. This in turn points to the possibility that the current Inuit population in Greenland is comprised of individuals of both Thule and Dorset descent.

Karyotyping human chromosomes by optical and x-ray ptychography methods

DOE PAGES

Shemilt, Laura; Verbanis, Ephanielle; Schwenke, Joerg; ...

2015-02-01

Sorting and identifying chromosomes, a process known as karyotyping, is widely used to detect changes in chromosome shapes and gene positions. In a karyotype the chromosomes are identified by their size and therefore this process can be performed by measuring macroscopic structural variables. Chromosomes contain a specific number of basepairs that linearly correlate with their size; therefore, it is possible to perform a karyotype on chromosomes using their mass as an identifying factor. Here, we obtain the first images, to our knowledge, of chromosomes using the novel imaging method of ptychography. We can use the images to measure the massmore » of chromosomes and perform a partial karyotype from the results. Lastly, we also obtain high spatial resolution using this technique with synchrotron source x-rays.« less

Karyotyping human chromosomes by optical and x-ray ptychography methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shemilt, Laura; Verbanis, Ephanielle; Schwenke, Joerg

Sorting and identifying chromosomes, a process known as karyotyping, is widely used to detect changes in chromosome shapes and gene positions. In a karyotype the chromosomes are identified by their size and therefore this process can be performed by measuring macroscopic structural variables. Chromosomes contain a specific number of basepairs that linearly correlate with their size; therefore, it is possible to perform a karyotype on chromosomes using their mass as an identifying factor. Here, we obtain the first images, to our knowledge, of chromosomes using the novel imaging method of ptychography. We can use the images to measure the massmore » of chromosomes and perform a partial karyotype from the results. Lastly, we also obtain high spatial resolution using this technique with synchrotron source x-rays.« less

Meiotic drive on aberrant chromosome 1 in the mouse is determined by a linked distorter.

PubMed

Agulnik, S I; Sabantsev, I D; Orlova, G V; Ruvinsky, A O

1993-04-01

An aberrant chromosome 1 carrying an inverted fragment with two amplified DNA regions was isolated from wild populations of Mus musculus. Meiotic drive favouring the aberrant chromosome was demonstrated for heterozygous females. Its cause was preferential passage of aberrant chromosome 1 to the oocyte. Genetic analysis allowed us to identify a two-component system conditioning deviation from equal segregation of the homologues. The system consists of a postulated distorter and responder. The distorter is located on chromosome 1 distally to the responder, between the ln and Pep-3 genes, and it acts on the responder when in trans position. Polymorphism of the distorters was manifested as variation in their effect on meiotic drive level in the laboratory strain and mice from wild populations.

Cytogenetic and molecular markers for detecting Aegilops uniaristata chromosomes in a wheat background.

PubMed

Gong, Wenping; Li, Guangrong; Zhou, Jianping; Li, Genying; Liu, Cheng; Huang, Chengyan; Zhao, Zhendong; Yang, Zujun

2014-09-01

Aegilops uniaristata has many agronomically useful traits that can be used for wheat breeding. So far, a Triticum turgidum - Ae. uniaristata amphiploid and one set of Chinese Spring (CS) - Ae. uniaristata addition lines have been produced. To guide Ae. uniaristata chromatin transformation from these lines into cultivated wheat through chromosome engineering, reliable cytogenetic and molecular markers specific for Ae. uniaristata chromosomes need to be developed. Standard C-banding shows that C-bands mainly exist in the centromeric regions of Ae. uniaristata but rarely at the distal ends. Fluorescence in situ hybridization (FISH) using (GAA)8 as a probe showed that the hybridization signal of chromosomes 1N-7N are different, thus (GAA)8 can be used to identify all Ae. uniaristata chromosomes in wheat background simultaneously. Moreover, a total of 42 molecular markers specific for Ae. uniaristata chromosomes were developed by screening expressed sequence tag - sequence tagged site (EST-STS), expressed sequence tag - simple sequence repeat (EST-SSR), and PCR-based landmark unique gene (PLUG) primers. The markers were subsequently localized using the CS - Ae. uniaristata addition lines and different wheat cultivars as controls. The cytogenetic and molecular markers developed herein will be helpful for screening and identifying wheat - Ae. uniaristata progeny.

[Meiotic drive for aberrant chromosome 1 in mice is determined by a linked distorter].

PubMed

Agul'nik, S I; Sabantsev, I D; Orlova, G V; Ruvinskiĭ, A O

1992-12-01

An aberrant chromosome 1 carrying an inverted fragment with two amplified DNA regions was isolated from natural populations of Mus musculus. A meiotic drive favouring the aberrant chromosome was previously demonstrated for heterozygous females. The cause for this was the preferential passage of the chromosome 1 to the oocyte. Genetic analysis made it possible to identify a two-component system conditioning the deviation from equal segregation of the homologues. The system consists of the postulated distorter and a responder. The distorter is located on the chromosome 1 distally to the responder, between the 1n and Pep 3 genes, the former acting on the responder when in the trans position. Polymorphism of the distorters was manifested as variation in their effect on the meiotic drive level in the laboratory strain and mice from natural populations.

Unique sex chromosome systems in Ellobius: How do male XX chromosomes recombine and undergo pachytene chromatin inactivation?

PubMed

Matveevsky, Sergey; Bakloushinskaya, Irina; Kolomiets, Oxana

2016-07-18

Most mammalian species have heteromorphic sex chromosomes in males, except for a few enigmatic groups such as the mole voles Ellobius, which do not have the Y chromosome and Sry gene. The Ellobius (XX ♀♂) system of sex chromosomes has no analogues among other animals. The structure and meiotic behaviour of the two X chromosomes were investigated for males of the sibling species Ellobius talpinus and Ellobius tancrei. Their sex chromosomes, despite their identical G-structure, demonstrate short synaptic fragments and crossover-associated MLH1 foci in both telomeric regions only. The chromatin undergoes modifications in the meiotic sex chromosomes. SUMO-1 marks a small nucleolus-like body of the meiotic XX. ATR and ubiH2A are localized in the asynaptic area and the histone γH2AFX covers the entire XX bivalent. The distribution of some markers of chromatin inactivation differentiates sex chromosomes of mole voles from those of other mammals. Sex chromosomes of both studied species have identical recombination and meiotic inactivation patterns. In Ellobius, similar chromosome morphology masks the functional heteromorphism of the male sex chromosomes, which can be seen at meiosis.

Unique sex chromosome systems in Ellobius: How do male XX chromosomes recombine and undergo pachytene chromatin inactivation?

PubMed Central

Matveevsky, Sergey; Bakloushinskaya, Irina; Kolomiets, Oxana

2016-01-01

Most mammalian species have heteromorphic sex chromosomes in males, except for a few enigmatic groups such as the mole voles Ellobius, which do not have the Y chromosome and Sry gene. The Ellobius (XX ♀♂) system of sex chromosomes has no analogues among other animals. The structure and meiotic behaviour of the two X chromosomes were investigated for males of the sibling species Ellobius talpinus and Ellobius tancrei. Their sex chromosomes, despite their identical G-structure, demonstrate short synaptic fragments and crossover-associated MLH1 foci in both telomeric regions only. The chromatin undergoes modifications in the meiotic sex chromosomes. SUMO-1 marks a small nucleolus-like body of the meiotic XX. ATR and ubiH2A are localized in the asynaptic area and the histone γH2AFX covers the entire XX bivalent. The distribution of some markers of chromatin inactivation differentiates sex chromosomes of mole voles from those of other mammals. Sex chromosomes of both studied species have identical recombination and meiotic inactivation patterns. In Ellobius, similar chromosome morphology masks the functional heteromorphism of the male sex chromosomes, which can be seen at meiosis. PMID:27425629

Higher 5-hydroxymethylcytosine identifies immortal DNA strand chromosomes in asymmetrically self-renewing distributed stem cells.

PubMed

Huh, Yang Hoon; Cohen, Justin; Sherley, James L

2013-10-15

Immortal strands are the targeted chromosomal DNA strands of nonrandom sister chromatid segregation, a mitotic chromosome segregation pattern unique to asymmetrically self-renewing distributed stem cells (DSCs). By nonrandom segregation, immortal DNA strands become the oldest DNA strands in asymmetrically self-renewing DSCs. Nonrandom segregation of immortal DNA strands may limit DSC mutagenesis, preserve DSC fate, and contribute to DSC aging. The mechanisms responsible for specification and maintenance of immortal DNA strands are unknown. To discover clues to these mechanisms, we investigated the 5-methylcytosine and 5-hydroxymethylcytosine (5hmC) content on chromosomes in mouse hair follicle DSCs during nonrandom segregation. Although 5-methylcytosine content did not differ significantly, the relative content of 5hmC was significantly higher in chromosomes containing immortal DNA strands than in opposed mitotic chromosomes containing younger mortal DNA strands. The difference in relative 5hmC content was caused by the loss of 5hmC from mortal chromosomes. These findings implicate higher 5hmC as a specific molecular determinant of immortal DNA strand chromosomes. Because 5hmC is an intermediate during DNA demethylation, we propose a ten-eleven translocase enzyme mechanism for both the specification and maintenance of nonrandomly segregated immortal DNA strands. The proposed mechanism reveals a means by which DSCs "know" the generational age of immortal DNA strands. The mechanism is supported by molecular expression data and accounts for the selection of newly replicated DNA strands when nonrandom segregation is initiated. These mechanistic insights also provide a possible basis for another characteristic property of immortal DNA strands, their guanine ribonucleotide dependency.

Linkage Block and Recombination Suppression at the Pi-ta locus at the Centromere Region of Rice Chromosome 12

USDA-ARS?s Scientific Manuscript database

The Pi-ta gene, located near the centromeric region of chromosome 12 is an effective resistance gene to Magnaporthe oryzae that causes rice blast disease. Pi-ta has been incorporated into diverse resistant rice cultivars by classical plant breeding in the southern US and worldwide. Previously, la...

Genetic conflict and sex chromosome evolution

PubMed Central

Meiklejohn, Colin D; Tao, Yun

2009-01-01

Chromosomal sex determination systems create the opportunity for the evolution of selfish genetic elements that increase the transmission of one sex chromosome at the expense of its homolog. Because such selfish elements on sex chromosomes can reduce fertility and distort the sex ratio of progeny, unlinked suppressors are expected to evolve, bringing different regions of the genome into conflict over the meiotic transmission of the sex chromosomes. Here we argue that recurrent genetic conflict over sex chromosome transmission is an important evolutionary force that has shaped a wide range of seemingly disparate phenomena including the epigenetic regulation of genes expressed in the germline, the distribution of genes in the genome, and the evolution of hybrid sterility between species. PMID:19931208

STS map of genes and anonymous DNA fragments on human chromosome 18 using a panel of somatic cell hybrids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Overhauser, J.; Mewar, R.; Rojas, K.

1993-02-01

Somatic cell hybrids containing different deleted regions of chromosome 18 derived form patients with balanced translocations or terminal deletions were used to create a deletion mapping panel. Twenty-four sequence-tagged sites (STSs) for 17 genes and 7 anonymous polymorphic DNA fragments were identified. These STSs were used to map the 24 loci to 18 defined regions of chromosome 18. Both ERV1, previously mapped to 18q22-q23, and YES1, previously mapped to 18q21.3, were found to map to 18p11.21-pter. Several genes previously mapped to 18q21 were found to be in the order cen-SSAV1-DCC-FECH-GRP-BCL2-PLANH2-tel. The precise mapping of genes to chromosome 18 should helpmore » in determining whether these genes may be involved in the etiology of specific chromosomal syndromes associated with chromosome 18. The mapping of the poloymorphic loci will assist in the integration of the physical map with the recombination map of chromosome 18. 43 refs., 2 figs., 1 tab.« less

Structure, organization, and sequence of alpha satellite DNA from human chromosome 17: evidence for evolution by unequal crossing-over and an ancestral pentamer repeat shared with the human X chromosome.

PubMed

Waye, J S; Willard, H F

1986-09-01

The centromeric regions of all human chromosomes are characterized by distinct subsets of a diverse tandemly repeated DNA family, alpha satellite. On human chromosome 17, the predominant form of alpha satellite is a 2.7-kilobase-pair higher-order repeat unit consisting of 16 alphoid monomers. We present the complete nucleotide sequence of the 16-monomer repeat, which is present in 500 to 1,000 copies per chromosome 17, as well as that of a less abundant 15-monomer repeat, also from chromosome 17. These repeat units were approximately 98% identical in sequence, differing by the exclusion of precisely 1 monomer from the 15-monomer repeat. Homologous unequal crossing-over is suggested as a probable mechanism by which the different repeat lengths on chromosome 17 were generated, and the putative site of such a recombination event is identified. The monomer organization of the chromosome 17 higher-order repeat unit is based, in part, on tandemly repeated pentamers. A similar pentameric suborganization has been previously demonstrated for alpha satellite of the human X chromosome. Despite the organizational similarities, substantial sequence divergence distinguishes these subsets. Hybridization experiments indicate that the chromosome 17 and X subsets are more similar to each other than to the subsets found on several other human chromosomes. We suggest that the chromosome 17 and X alpha satellite subsets may be related components of a larger alphoid subfamily which have evolved from a common ancestral repeat into the contemporary chromosome-specific subsets.

Border Structure of Intercalary Heterochromatin Bands of Drosophila melanogaster Polytene Chromosomes.

PubMed

Khoroshko, V A; Zykova, T Yu; Popova, O O; Zhimulev, I F

2018-03-01

The precise genomic localization of the borders of 62 intercalary heterochromatin bands in Drosophila polytene chromosomes was determined. A new type of bands containing chromatin of different states was identified. This type is a combination of the gray band and the intercalary heterochromatin band, creating a genetic structure that with a light microscope is identified as a continuous band. The border structure of such bands includes the coding regions of genes with ubiquitous activity.

Genetic Diversity on the Sex Chromosomes

PubMed Central

Wilson Sayres, Melissa A

2018-01-01

Abstract Levels and patterns of genetic diversity can provide insights into a population’s history. In species with sex chromosomes, differences between genomic regions with unique inheritance patterns can be used to distinguish between different sets of possible demographic and selective events. This review introduces the differences in population history for sex chromosomes and autosomes, provides the expectations for genetic diversity across the genome under different evolutionary scenarios, and gives an introductory description for how deviations in these expectations are calculated and can be interpreted. Predominantly, diversity on the sex chromosomes has been used to explore and address three research areas: 1) Mating patterns and sex-biased variance in reproductive success, 2) signatures of selection, and 3) evidence for modes of speciation and introgression. After introducing the theory, this review catalogs recent studies of genetic diversity on the sex chromosomes across species within the major research areas that sex chromosomes are typically applied to, arguing that there are broad similarities not only between male-heterogametic (XX/XY) and female-heterogametic (ZZ/ZW) sex determination systems but also any mating system with reduced recombination in a sex-determining region. Further, general patterns of reduced diversity in nonrecombining regions are shared across plants and animals. There are unique patterns across populations with vastly different patterns of mating and speciation, but these do not tend to cluster by taxa or sex determination system. PMID:29635328

Chromosomal evolution among leaf-nosed nectarivorous bats--evidence from cross-species chromosome painting (Phyllostomidae, Chiroptera).

PubMed

Sotero-Caio, Cibele G; Volleth, Marianne; Gollahon, Lauren S; Fu, Beiyuan; Cheng, William; Ng, Bee L; Yang, Fengtang; Baker, Robert J

2013-12-26

New World leaf-nosed bats, Phyllostomidae, represent a lineage of Chiroptera marked by unprecedented morphological/ecological diversity and extensive intergeneric chromosomal reorganization. There are still disagreements regarding their systematic relationships due to morphological convergence among some groups. Their history of karyotypic evolution also remains to be documented. To better understand the evolutionary relationships within Phyllostomidae, we developed chromosome paints from the bat species Macrotus californicus. We tested the potential of these paints as phylogenetic tools by looking for chromosomal signatures in two lineages of nectarivorous phyllostomids whose independent origins have been statistically supported by molecular phylogenies. By examining the chromosomal homologies defined by chromosome painting among two representatives of the subfamily Glossophaginae (Glossophaga soricina and Anoura cultrata) and one species from the subfamily Lonchophyllinae (Lonchophylla concava), we found chromosomal correspondence in regions not previously detected by other comparative cytogenetic techniques. We proposed the corresponding human chromosomal segments for chromosomes of the investigated species and found two syntenic associations shared by G. soricina and A. cultrata. Comparative painting with whole chromosome-specific paints of M. californicus demonstrates an extensive chromosomal reorganization within the two lineages of nectarivorous phyllostomids, with a large number of chromosomes shared between M. californicus and G. soricina. We show that the evolution of nectar-feeding bats occurs mainly by reshuffling of chiropteran Evolutionarily Conserved Units (ECUs). Robertsonian fusions/fissions and inversions seem to be important modifiers of phyllostomid karyotypes, and autapomorphic character states are common within species. Macrotus californicus chromosome paints will be a valuable tool for documenting the pattern of karyotypic evolution within

Genome-wide methylation analysis identified sexually dimorphic methylated regions in hybrid tilapia

PubMed Central

Wan, Zi Yi; Xia, Jun Hong; Lin, Grace; Wang, Le; Lin, Valerie C. L.; Yue, Gen Hua

2016-01-01

Sexual dimorphism is an interesting biological phenomenon. Previous studies showed that DNA methylation might play a role in sexual dimorphism. However, the overall picture of the genome-wide methylation landscape in sexually dimorphic species remains unclear. We analyzed the DNA methylation landscape and transcriptome in hybrid tilapia (Oreochromis spp.) using whole genome bisulfite sequencing (WGBS) and RNA-sequencing (RNA-seq). We found 4,757 sexually dimorphic differentially methylated regions (DMRs), with significant clusters of DMRs located on chromosomal regions associated with sex determination. CpG methylation in promoter regions was negatively correlated with the gene expression level. MAPK/ERK pathway was upregulated in male tilapia. We also inferred active cis-regulatory regions (ACRs) in skeletal muscle tissues from WGBS datasets, revealing sexually dimorphic cis-regulatory regions. These results suggest that DNA methylation contribute to sex-specific phenotypes and serve as resources for further investigation to analyze the functions of these regions and their contributions towards sexual dimorphisms. PMID:27782217

Chromosome segregation drives division site selection in Streptococcus pneumoniae.

PubMed

van Raaphorst, Renske; Kjos, Morten; Veening, Jan-Willem

2017-07-18

Accurate spatial and temporal positioning of the tubulin-like protein FtsZ is key for proper bacterial cell division. Streptococcus pneumoniae (pneumococcus) is an oval-shaped, symmetrically dividing opportunistic human pathogen lacking the canonical systems for division site control (nucleoid occlusion and the Min-system). Recently, the early division protein MapZ was identified and implicated in pneumococcal division site selection. We show that MapZ is important for proper division plane selection; thus, the question remains as to what drives pneumococcal division site selection. By mapping the cell cycle in detail, we show that directly after replication both chromosomal origin regions localize to the future cell division sites, before FtsZ. Interestingly, Z-ring formation occurs coincidently with initiation of DNA replication. Perturbing the longitudinal chromosomal organization by mutating the condensin SMC, by CRISPR/Cas9-mediated chromosome cutting, or by poisoning DNA decatenation resulted in mistiming of MapZ and FtsZ positioning and subsequent cell elongation. Together, we demonstrate an intimate relationship between DNA replication, chromosome segregation, and division site selection in the pneumococcus, providing a simple way to ensure equally sized daughter cells.

Localization of the human mitochondrial citrate transporter protein gene to chromosome 22q11 in the DiGeorge syndrome critical region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heisterkamp, N.; Hoeve, J.T.; Groffen, J.

A high percentage of patients with DiGeorge syndrome and velo-cardio-facial syndrome have interstitial deletions on chromosome 22q11. The shortest region of overlap is currently estimated to be around 500 kb. Two segments of DNA from chromosome 22q11, located 160 kb apart, were cloned because they contained NotI restriction enzyme sites. In the current study we demonstrate that these segments are absent from chromosomes 22 carrying microdeletions of two different DiGeorge patients. Fluorescence in situ and Southern blot hybridization was further used to show that this locus is within the DiGeorge critical region. Phylogenetically conserved sequences adjacent to one of themore » two NotI sites hybridized to mRNAs in different human cell lines. cDNAs isolated with a probe from this segment showed it to contain the gene for the human mitochondrial citrate transporter protein. Deletion of this gene in DiGeorge may contribute to the mental deficiency seen in the patients. 35 refs., 5 figs.« less

Characterization of the genomic organization of the region bordering the centromere of chromosome V of Podospora anserina by direct sequencing.

PubMed

Silar, Philippe; Barreau, Christian; Debuchy, Robert; Kicka, Sébastien; Turcq, Béatrice; Sainsard-Chanet, Annie; Sellem, Carole H; Billault, Alain; Cattolico, Laurence; Duprat, Simone; Weissenbach, Jean

2003-08-01

A Podospora anserina BAC library of 4800 clones has been constructed in the vector pBHYG allowing direct selection in fungi. Screening of the BAC collection for centromeric sequences of chromosome V allowed the recovery of clones localized on either sides of the centromere, but no BAC clone was found to contain the centromere. Seven BAC clones containing 322,195 and 156,244bp from either sides of the centromeric region were sequenced and annotated. One 5S rRNA gene, 5 tRNA genes, and 163 putative coding sequences (CDS) were identified. Among these, only six CDS seem specific to P. anserina. The gene density in the centromeric region is approximately one gene every 2.8kb. Extrapolation of this gene density to the whole genome of P. anserina suggests that the genome contains about 11,000 genes. Synteny analyses between P. anserina and Neurospora crassa show that co-linearity extends at the most to a few genes, suggesting rapid genome rearrangements between these two species.

Compositions for chromosome-specific staining

DOEpatents

Gray, Joe W.; Pinkel, Daniel

1998-01-01

Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. Said methods produce staining patterns that can be tailored for specific cytogenetic analyses. Said probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods are provided to disable the hybridization capacity of shared, high copy repetitive sequences and/or remove such sequences to provide for useful contrast. Still further methods are provided to produce chromosome-specific staining reagents which are made specific to the targeted chromosomal material, which can be one or more whole chromosomes, one or more regions on one or more chromosomes, subsets of chromosomes and/or the entire genome. Probes and test kits are provided for use in tumor cytogenetics, in the detection of disease related loci, in analysis of structural abnormalities, such as translocations, and for biological dosimetry. Further, methods and prenatal test kits are provided to stain targeted chromosomal material of fetal cells, including fetal cells obtained from maternal blood. Still further, the invention provides for automated means to detect and analyse chromosomal abnormalities.

Compositions for chromosome-specific staining

DOEpatents

Gray, J.W.; Pinkel, D.

1998-05-26

Methods and compositions for staining based upon nucleic acid sequence that employ nucleic acid probes are provided. The methods produce staining patterns that can be tailored for specific cytogenetic analyses. The probes are appropriate for in situ hybridization and stain both interphase and metaphase chromosomal material with reliable signals. The nucleic acid probes are typically of a complexity greater than 50 kb, the complexity depending upon the cytogenetic application. Methods are provided to disable the hybridization capacity of shared, high copy repetitive sequences and/or remove such sequences to provide for useful contrast. Still further methods are provided to produce chromosome-specific staining reagents which are made specific to the targeted chromosomal material, which can be one or more whole chromosomes, one or more regions on one or more chromosomes, subsets of chromosomes and/or the entire genome. Probes and test kits are provided for use in tumor cytogenetics, in the detection of disease related loci, in analysis of structural abnormalities, such as translocations, and for biological dosimetry. Methods and prenatal test kits are provided to stain targeted chromosomal material of fetal cells, including fetal cells obtained from maternal blood. The invention provides for automated means to detect and analyze chromosomal abnormalities. 17 figs.

Chromosome Banding in Amphibia. XXXVI. Multimorphic Sex Chromosomes and an Enigmatic Sex Determination in Eleutherodactylus johnstonei (Anura, Eleutherodactylidae).

PubMed

Schmid, Michael; Steinlein, Claus

2018-01-01

A detailed cytogenetic study on the leaf litter frog Eleutherodactylus johnstonei from 14 different Caribbean islands and the mainlands of Venezuela and Guyana revealed the existence of multimorphic XY♂/XX♀ sex chromosomes 14. Their male sex determination and development depends either on the presence of 2 telocentric chromosomes 14 (XtYt), or on 1 submetacentric chromosome 14 (Xsm) plus 1 telocentric chromosome 14 (Yt), or on the presence of 2 submetacentric chromosomes 14 (XsmYsm). The female sex determination and development requires either the presence of 2 telocentric chromosomes 14 (XtXt) or 2 submetacentric chromosomes 14 (XsmXsm). In all individuals analyzed, the sex chromosomes 14 carry a prominent nucleolus organizer region in their long arms. An explanation is given for the origin of the (XtYt)♂, (XsmYt)♂, (XsmYsm)♂, (XtXt)♀, and (XsmXsm)♀ in the different populations of E. johnstonei. Furthermore, the present study gives detailed data on the chromosome banding patterns, in situ hybridization experiments, and the genome size of E. johnstonei. © 2018 S. Karger AG, Basel.

Genomic analysis of the chromosome 15q11-q13 Prader-Willi syndrome region and characterization of transcripts for GOLGA8E and WHCD1L1 from the proximal breakpoint region.

PubMed

Jiang, Yong-Hui; Wauki, Kekio; Liu, Qian; Bressler, Jan; Pan, Yanzhen; Kashork, Catherine D; Shaffer, Lisa G; Beaudet, Arthur L

2008-01-28

Prader-Willi syndrome (PWS) is a neurobehavioral disorder characterized by neonatal hypotonia, childhood obesity, dysmorphic features, hypogonadism, mental retardation, and behavioral problems. Although PWS is most often caused by a paternal interstitial deletion of a 6-Mb region of chromosome 15q11-q13, the identity of the exact protein coding or noncoding RNAs whose deficiency produces the PWS phenotype is uncertain. There are also reports describing a PWS-like phenotype in a subset of patients with full mutations in the FMR1 (fragile X mental retardation 1) gene. Taking advantage of the human genome sequence, we have performed extensive sequence analysis and molecular studies for the PWS candidate region. We have characterized transcripts for the first time for two UCSC Genome Browser predicted protein-coding genes, GOLGA8E (golgin subfamily a, 8E) and WHDC1L1 (WAS protein homology region containing 1-like 1) and have further characterized two previously reported genes, CYF1P1 and NIPA2; all four genes are in the region close to the proximal/centromeric deletion breakpoint (BP1). GOLGA8E belongs to the golgin subfamily of coiled-coil proteins associated with the Golgi apparatus. Six out of 16 golgin subfamily proteins in the human genome have been mapped in the chromosome 15q11-q13 and 15q24-q26 regions. We have also identified more than 38 copies of GOLGA8E-like sequence in the 15q11-q14 and 15q23-q26 regions which supports the presence of a GOLGA8E-associated low copy repeat (LCR). Analysis of the 15q11-q13 region by PFGE also revealed a polymorphic region between BP1 and BP2. WHDC1L1 is a novel gene with similarity to mouse Whdc1 (WAS protein homology region 2 domain containing 1) and human JMY protein (junction-mediating and regulatory protein). Expression analysis of cultured human cells and brain tissues from PWS patients indicates that CYFIP1 and NIPA2 are biallelically expressed. However, we were not able to determine the allele-specific expression

Progressive Recombination Suppression and Differentiation in Recently Evolved Neo-sex Chromosomes

PubMed Central

Natri, Heini M.; Shikano, Takahito; Merilä, Juha

2013-01-01

Recombination suppression leads to the structural and functional differentiation of sex chromosomes and is thus a crucial step in the process of sex chromosome evolution. Despite extensive theoretical work, the exact processes and mechanisms of recombination suppression and differentiation are not well understood. In threespine sticklebacks (Gasterosteus aculeatus), a different sex chromosome system has recently evolved by a fusion between the Y chromosome and an autosome in the Japan Sea lineage, which diverged from the ancestor of other lineages approximately 2 Ma. We investigated the evolutionary dynamics and differentiation processes of sex chromosomes based on comparative analyses of these divergent lineages using 63 microsatellite loci. Both chromosome-wide differentiation patterns and phylogenetic inferences with X and Y alleles indicated that the ancestral sex chromosomes were extensively differentiated before the divergence of these lineages. In contrast, genetic differentiation appeared to have proceeded only in a small region of the neo-sex chromosomes. The recombination maps constructed for the Japan Sea lineage indicated that recombination has been suppressed or reduced over a large region spanning the ancestral and neo-sex chromosomes. Chromosomal regions exhibiting genetic differentiation and suppressed or reduced recombination were detected continuously and sequentially in the neo-sex chromosomes, suggesting that differentiation has gradually spread from the fusion point following the extension of recombination suppression. Our study illustrates an ongoing process of sex chromosome differentiation, providing empirical support for the theoretical model postulating that recombination suppression and differentiation proceed in a gradual manner in the very early stage of sex chromosome evolution. PMID:23436913

Higher 5-hydroxymethylcytosine identifies immortal DNA strand chromosomes in asymmetrically self-renewing distributed stem cells

PubMed Central

Huh, Yang Hoon; Cohen, Justin; Sherley, James L.

2013-01-01

Immortal strands are the targeted chromosomal DNA strands of nonrandom sister chromatid segregation, a mitotic chromosome segregation pattern unique to asymmetrically self-renewing distributed stem cells (DSCs). By nonrandom segregation, immortal DNA strands become the oldest DNA strands in asymmetrically self-renewing DSCs. Nonrandom segregation of immortal DNA strands may limit DSC mutagenesis, preserve DSC fate, and contribute to DSC aging. The mechanisms responsible for specification and maintenance of immortal DNA strands are unknown. To discover clues to these mechanisms, we investigated the 5-methylcytosine and 5-hydroxymethylcytosine (5hmC) content on chromosomes in mouse hair follicle DSCs during nonrandom segregation. Although 5-methylcytosine content did not differ significantly, the relative content of 5hmC was significantly higher in chromosomes containing immortal DNA strands than in opposed mitotic chromosomes containing younger mortal DNA strands. The difference in relative 5hmC content was caused by the loss of 5hmC from mortal chromosomes. These findings implicate higher 5hmC as a specific molecular determinant of immortal DNA strand chromosomes. Because 5hmC is an intermediate during DNA demethylation, we propose a ten-eleven translocase enzyme mechanism for both the specification and maintenance of nonrandomly segregated immortal DNA strands. The proposed mechanism reveals a means by which DSCs “know” the generational age of immortal DNA strands. The mechanism is supported by molecular expression data and accounts for the selection of newly replicated DNA strands when nonrandom segregation is initiated. These mechanistic insights also provide a possible basis for another characteristic property of immortal DNA strands, their guanine ribonucleotide dependency. PMID:24082118

Chromosomal aberrations evaluated by CGH, FISH and GTG-banding in a case of AIDS-related Burkitt's lymphoma.

PubMed

Zunino, A; Viaggi, S; Ottaggio, L; Fronza, G; Schenone, A; Roncella, S; Abbondandolo, A

2000-03-01

We have previously reported on a complex chromosome rearrangement [der(17)] in a B-cell line, BRG A, established from an AIDS patient with Burkitt's lymphoma (BL). The aim of the present study was the definition of der(17) composition and the identification of complete or partial chromosome gains and losses in two cell clones (BRG A and BRG M) derived from this patient. We applied comparative genome hybridization (CGH) to detect the DNA misrepresentations in the genome of the two cell clones. Findings from CGH and banding analysis could then direct the choice of probes for chromosome painting experiments to elucidate der(17) composition. CGH analysis identified gains of chromosomes 1q, 7q, 12q, 13q, 15q, 17p, 20p,q and losses of chromosomes 3p and 5q in BRG A and gain of chromosome 1q and loss in chromosome 6q in BRG M. Some of the detected alterations had already been described in lymphomas, while others appeared to be new. The combination of these techniques allowed a precise definition of der(17), composed by translocated regions from chromosomes 12 and 15. We demonstrated CGH to be a powerful tool in the identification of recurrent chromosome aberrations in an AIDS-related BL and in ascertaining the origin of marker chromosomes. We were also able to identify a different pattern of aberrations and assess an independent sequence of events leading to the 1p gain in the two subclones.

A Segment of the Apospory-Specific Genomic Region Is Highly Microsyntenic Not Only between the Apomicts Pennisetum squamulatum and Buffelgrass, But Also with a Rice Chromosome 11 Centromeric-Proximal Genomic Region1[W

PubMed Central

Gualtieri, Gustavo; Conner, Joann A.; Morishige, Daryl T.; Moore, L. David; Mullet, John E.; Ozias-Akins, Peggy

2006-01-01

Bacterial artificial chromosome (BAC) clones from apomicts Pennisetum squamulatum and buffelgrass (Cenchrus ciliaris), isolated with the apospory-specific genomic region (ASGR) marker ugt197, were assembled into contigs that were extended by chromosome walking. Gene-like sequences from contigs were identified by shotgun sequencing and BLAST searches, and used to isolate orthologous rice contigs. Additional gene-like sequences in the apomicts' contigs were identified by bioinformatics using fully sequenced BACs from orthologous rice contigs as templates, as well as by interspecies, whole-contig cross-hybridizations. Hierarchical contig orthology was rapidly assessed by constructing detailed long-range contig molecular maps showing the distribution of gene-like sequences and markers, and searching for microsyntenic patterns of sequence identity and spatial distribution within and across species contigs. We found microsynteny between P. squamulatum and buffelgrass contigs. Importantly, this approach also enabled us to isolate from within the rice (Oryza sativa) genome contig Rice A, which shows the highest microsynteny and is most orthologous to the ugt197-containing C1C buffelgrass contig. Contig Rice A belongs to the rice genome database contig 77 (according to the current September 12, 2003, rice fingerprint contig build) that maps proximal to the chromosome 11 centromere, a feature that interestingly correlates with the mapping of ASGR-linked BACs proximal to the centromere or centromere-like sequences. Thus, relatedness between these two orthologous contigs is supported both by their molecular microstructure and by their centromeric-proximal location. Our discoveries promote the use of a microsynteny-based positional-cloning approach using the rice genome as a template to aid in constructing the ASGR toward the isolation of genes underlying apospory. PMID:16415213

Quantitative trait loci at the 11q23.3 chromosomal region related to dyslipidemia in the population of Andhra Pradesh, India.

PubMed

Pranavchand, Rayabarapu; Reddy, Battini Mohan

2017-06-13

Given the characteristic atherogenic dyslipidemia of south Indian population and crucial role of APOA1, APOC3, APOA4 and APOA5 genes clustered in 11q23.3 chromosomal region in regulating lipoprotein metabolism and cholesterol homeostasis, a large number of recently identified variants are to be explored for their role in regulating the serum lipid parameters among south Indians. Using fluidigm SNP genotyping platform, a prioritized set of 96 SNPs of the 11q23.3 chromosomal region were genotyped on 516 individuals from Hyderabad, India, and its vicinity and aged >45 years. The linear regression analysis of the individual lipid traits viz., TC, LDLC, HDLC, VLDL and TG with each of the 78 SNPs that confirm to HWE and with minor allele frequency > 1%, suggests 23 of those to be significantly associated (p ≤ 0.05) with at least one of these quantitative traits. Most importantly, the variant rs632153 is involved in elevating TC, LDLC, TG and VLDLs and probably playing a crucial role in the manifestation of dyslipidemia. Additionally, another three SNPs rs633389, rs2187126 and rs1263163 are found risk conferring to dyslipidemia by elevating LDLC and TC levels in the present population. Further, the ROC (receiver operating curve) analysis for the risk scores and dyslipidemia status yielded a significant area under curve (AUC) = 0.675, suggesting high discriminative power of the risk variants towards the condition. The interaction analysis suggests rs10488699-rs2187126 pair of the BUD13 gene to confer significant risk (Interaction odds ratio = 14.38, P = 7.17 × 10 5 ) towards dyslipidemia by elevating the TC levels (β = 37.13, p = 6.614 × 10 5 ). On the other hand, the interaction between variants of APOA1 gene and BUD13 and/or ZPR1 regulatory genes at this region are associated with elevated TG and VLDL. The variants at 11q23.3 chromosomal region seem to determine the quantitative lipid traits and in turn dyslipidemia in the population of Hyderabad

Single nucleotide polymorphisms in an intergenic chromosome 2q region associated with tissue factor pathway inhibitor plasma levels and venous thromboembolism.

PubMed

Dennis, J; Truong, V; Aïssi, D; Medina-Rivera, A; Blankenberg, S; Germain, M; Lemire, M; Antounians, L; Civelek, M; Schnabel, R; Wells, P; Wilson, M D; Morange, P-E; Trégouët, D-A; Gagnon, F

2016-10-01

Essentials Tissue factor pathway inhibitor (TFPI) regulates the blood coagulation cascade. We replicated previously reported linkage of TFPI plasma levels to the chromosome 2q region. The putative causal locus, rs62187992, was associated with TFPI plasma levels and thrombosis. rs62187992 was marginally associated with TFPI expression in human aortic endothelial cells. Click to hear Ann Gil's presentation on new insights into thrombin activatable fibrinolysis inhibitor SUMMARY: Background Tissue factor pathway inhibitor (TFPI) regulates fibrin clot formation, and low TFPI plasma levels increase the risk of arterial thromboembolism and venous thromboembolism (VTE). TFPI plasma levels are also heritable, and a previous linkage scan implicated the chromosome 2q region, but no specific genes. Objectives To replicate the finding of the linkage region in an independent sample, and to identify the causal locus. Methods We first performed a linkage analysis of microsatellite markers and TFPI plasma levels in 251 individuals from the F5L Family Study, and replicated the finding of the linkage peak on chromosome 2q (LOD = 3.06). We next defined a follow-up region that included 112 603 single nucleotide polymorphisms (SNPs) under the linkage peak, and meta-analyzed associations between these SNPs and TFPI plasma levels across the F5L Family Study and the Marseille Thrombosis Association (MARTHA) Study, a study of 1033 unrelated VTE patients. SNPs with false discovery rate q-values of < 0.10 were tested for association with TFPI plasma levels in 892 patients with coronary artery disease in the AtheroGene Study. Results and Conclusions One SNP, rs62187992, was associated with TFPI plasma levels in all three samples (β = + 0.14 and P = 4.23 × 10 -6 combined; β = + 0.16 and P = 0.02 in the F5L Family Study; β = + 0.13 and P = 6.3 × 10 -4 in the MARTHA Study; β = + 0.17 and P = 0.03 in the AtheroGene Study), and contributed to the linkage peak in the F5L Family Study. rs

SNPs in putative regulatory regions identified by human mouse comparative sequencing and transcription factor binding site data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee, Poulabi; Bahlo, Melanie; Schwartz, Jody R.

2002-01-01

Genome wide disease association analysis using SNPs is being explored as a method for dissecting complex genetic traits and a vast number of SNPs have been generated for this purpose. As there are cost and throughput limitations of genotyping large numbers of SNPs and statistical issues regarding the large number of dependent tests on the same data set, to make association analysis practical it has been proposed that SNPs should be prioritized based on likely functional importance. The most easily identifiable functional SNPs are coding SNPs (cSNPs) and accordingly cSNPs have been screened in a number of studies. SNPs inmore » gene regulatory sequences embedded in noncoding DNA are another class of SNPs suggested for prioritization due to their predicted quantitative impact on gene expression. The main challenge in evaluating these SNPs, in contrast to cSNPs is a lack of robust algorithms and databases for recognizing regulatory sequences in noncoding DNA. Approaches that have been previously used to delineate noncoding sequences with gene regulatory activity include cross-species sequence comparisons and the search for sequences recognized by transcription factors. We combined these two methods to sift through mouse human genomic sequences to identify putative gene regulatory elements and subsequently localized SNPs within these sequences in a 1 Megabase (Mb) region of human chromosome 5q31, orthologous to mouse chromosome 11 containing the Interleukin cluster.« less

Detection of Inter-chromosomal Stable Aberrations by Multiple Fluorescence In Situ Hybridization (mFISH) and Spectral Karyotyping (SKY) in Irradiated Mice

PubMed Central

Pathak, Rupak; Koturbash, Igor; Hauer-Jensen, Martin

2017-01-01

Ionizing radiation (IR) induces numerous stable and unstable chromosomal aberrations. Unstable aberrations, where chromosome morphology is substantially compromised, can easily be identified by conventional chromosome staining techniques. However, detection of stable aberrations, which involve exchange or translocation of genetic materials without considerable modification in the chromosome morphology, requires sophisticated chromosome painting techniques that rely on in situ hybridization of fluorescently labeled DNA probes, a chromosome painting technique popularly known as fluorescence in situ hybridization (FISH). FISH probes can be specific for whole chromosome/s or precise sub-region on chromosome/s. The method not only allows visualization of stable aberrations, but it can also allow detection of the chromosome/s or specific DNA sequence/s involved in a particular aberration formation. A variety of chromosome painting techniques are available in cytogenetics; here two highly sensitive methods, multiple fluorescence in situ hybridization (mFISH) and spectral karyotyping (SKY), are discussed to identify inter-chromosomal stable aberrations that form in the bone marrow cells of mice after exposure to total body irradiation. Although both techniques rely on fluorescent labeled DNA probes, the method of detection and the process of image acquisition of the fluorescent signals are different. These two techniques have been used in various research areas, such as radiation biology, cancer cytogenetics, retrospective radiation biodosimetry, clinical cytogenetics, evolutionary cytogenetics, and comparative cytogenetics. PMID:28117817

Simulated binding of transcription factors to active and inactive regions folds human chromosomes into loops, rosettes and topological domains

PubMed Central

Brackley, Chris A.; Johnson, James; Kelly, Steven; Cook, Peter R.; Marenduzzo, Davide

2016-01-01

Biophysicists are modeling conformations of interphase chromosomes, often basing the strengths of interactions between segments distant on the genetic map on contact frequencies determined experimentally. Here, instead, we develop a fitting-free, minimal model: bivalent or multivalent red and green ‘transcription factors’ bind to cognate sites in strings of beads (‘chromatin’) to form molecular bridges stabilizing loops. In the absence of additional explicit forces, molecular dynamic simulations reveal that bound factors spontaneously cluster—red with red, green with green, but rarely red with green—to give structures reminiscent of transcription factories. Binding of just two transcription factors (or proteins) to active and inactive regions of human chromosomes yields rosettes, topological domains and contact maps much like those seen experimentally. This emergent ‘bridging-induced attraction’ proves to be a robust, simple and generic force able to organize interphase chromosomes at all scales. PMID:27060145

A polymorphic pseudoautosomal boundary in the Carica papaya sex chromosomes.

PubMed

Lappin, Fiona M; Medert, Charles M; Hawkins, Kevin K; Mardonovich, Sandra; Wu, Meng; Moore, Richard C

2015-08-01

Sex chromosomes are defined by a non-recombining sex-determining region (SDR) flanked by one or two pseudoautosomal regions (PARs). The genetic composition and evolutionary dynamics of the PAR is also influenced by its linkage to the differentiated non-recombining SDR; however, understanding the effects of this linkage requires a precise definition of the PAR boundary. Here, we took a molecular population genetic approach to further refine the location of the PAR boundary of the evolutionary young sex chromosomes of the tropical plant, Carica papaya. We were able to map the position of the papaya PAR boundary A to a 100-kb region between two genetic loci approximately 2 Mb upstream of the previously genetically identified PAR boundary. Furthermore, this boundary is polymorphic within natural populations of papaya, with an approximately 100-130 kb expansion of the non-recombining SDR found in 16 % of individuals surveyed. The expansion of the PAR boundary in one Y haplotype includes at least one additional gene. Homologs of this gene are involved in male gametophyte and pollen development in other plant species.

A general method for identifying major hybrid male sterility genes in Drosophila.

PubMed

Zeng, L W; Singh, R S

1995-10-01

The genes responsible for hybrid male sterility in species crosses are usually identified by introgressing chromosome segments, monitored by visible markers, between closely related species by continuous backcrosses. This commonly used method, however, suffers from two problems. First, it relies on the availability of markers to monitor the introgressed regions and so the portion of the genome examined is limited to the marked regions. Secondly, the introgressed regions are usually large and it is impossible to tell if the effects of the introgressed regions are the result of single (or few) major genes or many minor genes (polygenes). Here we introduce a simple and general method for identifying putative major hybrid male sterility genes which is free of these problems. In this method, the actual hybrid male sterility genes (rather than markers), or tightly linked gene complexes with large effects, are selectively introgressed from one species into the background of another species by repeated backcrosses. This is performed by selectively backcrossing heterozygous (for hybrid male sterility gene or genes) females producing fertile and sterile sons in roughly equal proportions to males of either parental species. As no marker gene is required for this procedure, this method can be used with any species pairs that produce unisexual sterility. With the application of this method, a small X chromosome region of Drosophila mauritiana which produces complete hybrid male sterility (aspermic testes) in the background of D. simulans was identified. Recombination analysis reveals that this region contains a second major hybrid male sterility gene linked to the forked locus located at either 62.7 +/- 0.66 map units or at the centromere region of the X chromosome of D. mauritiana.

Identification of Mitosis-Specific Phosphorylation in Mitotic Chromosome-Associated Proteins.

PubMed

Ohta, Shinya; Kimura, Michiko; Takagi, Shunsuke; Toramoto, Iyo; Ishihama, Yasushi

2016-09-02

During mitosis, phosphorylation of chromosome-associated proteins is a key regulatory mechanism. Mass spectrometry has been successfully applied to determine the complete protein composition of mitotic chromosomes, but not to identify post-translational modifications. Here, we quantitatively compared the phosphoproteome of isolated mitotic chromosomes with that of chromosomes in nonsynchronized cells. We identified 4274 total phosphorylation sites and 350 mitosis-specific phosphorylation sites in mitotic chromosome-associated proteins. Significant mitosis-specific phosphorylation in centromere/kinetochore proteins was detected, although the chromosomal association of these proteins did not change throughout the cell cycle. This mitosis-specific phosphorylation might play a key role in regulation of mitosis. Further analysis revealed strong dependency of phosphorylation dynamics on kinase consensus patterns, thus linking the identified phosphorylation sites to known key mitotic kinases. Remarkably, chromosomal axial proteins such as non-SMC subunits of condensin, TopoIIα, and Kif4A, together with the chromosomal periphery protein Ki67 involved in the establishment of the mitotic chromosomal structure, demonstrated high phosphorylation during mitosis. These findings suggest a novel mechanism for regulation of chromosome restructuring in mitosis via protein phosphorylation. Our study generated a large quantitative database on protein phosphorylation in mitotic and nonmitotic chromosomes, thus providing insights into the dynamics of chromatin protein phosphorylation at mitosis onset.

Highly distinct chromosomal structures in cowpea (Vigna unguiculata), as revealed by molecular cytogenetic analysis.

PubMed

Iwata-Otsubo, Aiko; Lin, Jer-Young; Gill, Navdeep; Jackson, Scott A

2016-05-01

Cowpea (Vigna unguiculata (L.) Walp) is an important legume, particularly in developing countries. However, little is known about its genome or chromosome structure. We used molecular cytogenetics to characterize the structure of pachytene chromosomes to advance our knowledge of chromosome and genome organization of cowpea. Our data showed that cowpea has highly distinct chromosomal structures that are cytologically visible as brightly DAPI-stained heterochromatic regions. Analysis of the repetitive fraction of the cowpea genome present at centromeric and pericentromeric regions confirmed that two retrotransposons are major components of pericentromeric regions and that a 455-bp tandem repeat is found at seven out of 11 centromere pairs in cowpea. These repeats likely evolved after the divergence of cowpea from common bean and form chromosomal structure unique to cowpea. The integration of cowpea genetic and physical chromosome maps reveals potential regions of suppressed recombination due to condensed heterochromatin and a lack of pairing in a few chromosomal termini. This study provides fundamental knowledge on cowpea chromosome structure and molecular cytogenetics tools for further chromosome studies.

RNA sequencing of esophageal adenocarcinomas identifies novel fusion transcripts, including NPC1-MELK, arising from a complex chromosomal rearrangement.

PubMed

Wang, Zhixiong; Cheng, Yulan; Abraham, John M; Yan, Rong; Liu, Xi; Chen, Wei; Ibrahim, Sariat; Schroth, Gary P; Ke, Xiquan; He, Yulong; Meltzer, Stephen J

2017-10-15

Studies of chromosomal rearrangements and fusion transcripts have elucidated mechanisms of tumorigenesis and led to targeted cancer therapies. This study was aimed at identifying novel fusion transcripts in esophageal adenocarcinoma (EAC). To identify new fusion transcripts associated with EAC, targeted RNA sequencing and polymerase chain reaction (PCR) verification were performed in 40 EACs and matched nonmalignant specimens from the same patients. Genomic PCR and Sanger sequencing were performed to find the breakpoint of fusion genes. Five novel in-frame fusion transcripts were identified and verified in 40 EACs and in a validation cohort of 15 additional EACs (55 patients in all): fibroblast growth factor receptor 2 (FGFR2)-GRB2-associated binding protein 2 (GAB2) in 2 of 55 or 3.6%, Niemann-Pick C1 (NPC1)-maternal embryonic leucine zipper kinase (MELK) in 2 of 55 or 3.6%, ubiquitin-specific peptidase 54 (USP54)-calcium/calmodulin dependent protein kinase II γ (CAMK2G) in 2 of 55 or 3.6%, megakaryoblastic leukemia (translocation) 1 (MKL1)-fibulin 1 (FBLN1) in 1 of 55 or 1.8%, and CCR4-NOT transcription complex subunit 2 (CNOT2)-chromosome 12 open reading frame 49 (C12orf49) in 1 of 55 or 1.8%. A genomic analysis indicated that NPC1-MELK arose from a complex interchromosomal translocation event involving chromosomes 18, 3, and 9 with 3 rearrangement points, and this was consistent with chromoplexy. These data indicate that fusion transcripts occur at a stable frequency in EAC. Furthermore, our results indicate that chromoplexy is an underlying mechanism that generates fusion transcripts in EAC. These and other fusion transcripts merit further study as diagnostic markers and potential therapeutic targets in EAC. Cancer 2017;123:3916-24. © 2017 American Cancer Society. © 2017 American Cancer Society.

Technique of laser chromosome welding for chromosome repair and artificial chromosome creation.

PubMed

Huang, Yao-Xiong; Li, Lin; Yang, Liu; Zhang, Yi

2018-04-01

Here we report a technique of laser chromosome welding that uses a violet pulse laser micro-beam for welding. The technique can integrate any size of a desired chromosome fragment into recipient chromosomes by combining with other techniques of laser chromosome manipulation such as chromosome cutting, moving, and stretching. We demonstrated that our method could perform chromosomal modifications with high precision, speed and ease of use in the absence of restriction enzymes, DNA ligases and DNA polymerases. Unlike the conventional methods such as de novo artificial chromosome synthesis, our method has no limitation on the size of the inserted chromosome fragment. The inserted DNA size can be precisely defined and the processed chromosome can retain its intrinsic structure and integrity. Therefore, our technique provides a high quality alternative approach to directed genetic recombination, and can be used for chromosomal repair, removal of defects and artificial chromosome creation. The technique may also have applicability on the manipulation and extension of large pieces of synthetic DNA.

[The polymorphism of catechol-O-methyltransferase (COMT) and hemochromatosis (HFE) genes in the radiocontaminated regions residents with different chromosome aberration frequency].

PubMed

Ivanova, T I; Kondrashova, T V; Krikunova, L I; Smirnova, I A; Shentereva, N I; Sychenkova, N I; Rykova, E V; Zharikova, I A; Khorokhorina, V A; Riabchenko, N I; Zamulaeva, I A

2010-01-01

The association between polymorphisms in genes COMT, HFE that takes part in oxidative stress regulation, and chromosome aberration frequency in lymphocytes was assessed in 278 female residents of radiation polluted regions of Central Russia: Bryansk (322 kBk/m2) and Tula Districts (137Cs - 171 kBk/m2). The C187G, G845A genotyping of HFE and G1947A (H/L) of COMT was done by means of polymerase chain reaction-restriction fragment length polymorphism. Studied population was divided into 3 subgroups by level of chromosome aberrations per cell (0-2, 3-4, >5). There was shown statistically significant difference in distribution of COMTand HFE genotypes between the groups. The high frequency of chromosome aberrations (> or = 5%) was associated with homozygotes of the high activity COMT G/G and HFE CC. Heterozygotes for G1947A COMT and C187G HFE reveal negative association with the high frequency of chromosome aberrations and correspond to "resistance factors".

High-density marker profiling confirms ancestral genomes of Avena species and identifies D-genome chromosomes of hexaploid oat.

PubMed

Yan, Honghai; Bekele, Wubishet A; Wight, Charlene P; Peng, Yuanying; Langdon, Tim; Latta, Robert G; Fu, Yong-Bi; Diederichsen, Axel; Howarth, Catherine J; Jellen, Eric N; Boyle, Brian; Wei, Yuming; Tinker, Nicholas A

2016-11-01

Genome analysis of 27 oat species identifies ancestral groups, delineates the D genome, and identifies ancestral origin of 21 mapped chromosomes in hexaploid oat. We investigated genomic relationships among 27 species of the genus Avena using high-density genetic markers revealed by genotyping-by-sequencing (GBS). Two methods of GBS analysis were used: one based on tag-level haplotypes that were previously mapped in cultivated hexaploid oat (A. sativa), and one intended to sample and enumerate tag-level haplotypes originating from all species under investigation. Qualitatively, both methods gave similar predictions regarding the clustering of species and shared ancestral genomes. Furthermore, results were consistent with previous phylogenies of the genus obtained with conventional approaches, supporting the robustness of whole genome GBS analysis. Evidence is presented to justify the final and definitive classification of the tetraploids A. insularis, A. maroccana (=A. magna), and A. murphyi as containing D-plus-C genomes, and not A-plus-C genomes, as is most often specified in past literature. Through electronic painting of the 21 chromosome representations in the hexaploid oat consensus map, we show how the relative frequency of matches between mapped hexaploid-derived haplotypes and AC (DC)-genome tetraploids vs. A- and C-genome diploids can accurately reveal the genome origin of all hexaploid chromosomes, including the approximate positions of inter-genome translocations. Evidence is provided that supports the continued classification of a diverged B genome in AB tetraploids, and it is confirmed that no extant A-genome diploids, including A. canariensis, are similar enough to the D genome of tetraploid and hexaploid oat to warrant consideration as a D-genome diploid.

The molecular karyotype of the megabase chromosomes of Trypanosoma brucei stock 427.

PubMed

Melville, S E; Leech, V; Navarro, M; Cross, G A

2000-12-01

We present the molecular karyotype of the megabase chromosomes of Trypanosoma brucei stock 427, clone 221a. This cloned stock is most commonly used in research laboratories in genetic manipulation experiments and in studies of antigenic variation. Using 116 previously characterised chromosome-specific markers, we identify 11 diploid pairs of megabase chromosomes and detect no loss of synteny in EST and gene marker distribution between this stock and the genome project reference stock TREU 927/4. Nevertheless, the chromosomes of 427 are all larger than their homologues in 927, except chromosomes IIa and IXa. The greatest size variation is seen in chromosome I, the smallest of which is 1.1 Mb (927-Ia) and the largest 3.6 Mb (427-Ib). The total nuclear DNA content of both stocks has been estimated by comparison of the mobility of T. brucei and yeast chromosomes. Trypanosomes of stock 427 contain approximately 16.5 Mb more megabase chromosomal DNA than those of stock 927. We have detected the presence of bloodstream-form expression-site-associated sequences on eight or more megabase chromosomes. These sequences are not found on the same chromosomes in each stock. We have determined the chromosomal band location of nine characterised variant surface glycoprotein genes, including the currently expressed VSG 221. Our results demonstrate both the stability of the T. brucei genome, as illustrated by the conservation of syntenic groups of genes in the two stocks, and the polymorphic nature of the genomic regions involved in antigenic variation. We propose that the chromosomes of stock 427 be numbered to correspond to their homologues in the genome project reference stock TREU 927/4.

Chromosome Banding in Amphibia. XXXII. The Genus Xenopus (Anura, Pipidae).

PubMed

Schmid, Michael; Steinlein, Claus

2015-01-01

Mitotic chromosomes of 16 species of the frog genus Xenopus were prepared from kidney and lung cell cultures. In the chromosomes of 7 species, high-resolution replication banding patterns could be induced by treating the cultures with 5-bromodeoxyuridine (BrdU) and deoxythymidine (dT) in succession, and in 6 of these species the BrdU/dT-banded chromosomes could be arranged into karyotypes. In the 3 species of the clade with 2n = 20 and 4n = 40 chromosomes (X. tropicalis, X. epitropicalis, X. new tetraploid 1), as well as in the 3 species with 4n = 36 chromosomes (X. laevis, X. borealis, X. muelleri), the BrdU/dT-banded karyotypes show a high degree of homoeology, though differences were detected between these groups. Translocations, inversions, insertions or sex-specific replication bands were not observed. Minor replication asynchronies found between chromosomes probably involve heterochromatic regions. BrdU/dT replication banding of Xenopus chromosomes provides the landmarks necessary for the exact physical mapping of genes and repetitive sequences. FISH with an X. laevis 5S rDNA probe detected multiple hybridization sites at or near the long-arm telomeric regions in most chromosomes of X. laevis and X. borealis, whereas in X. muelleri, the 5S rDNA sequences are located exclusively at the long-arm telomeres of a single chromosome pair. Staining with the AT base pair-specific fluorochrome quinacrine mustard revealed brightly fluorescing heterochromatic regions in the majority of X. borealis chromosomes which are absent in other Xenopus species.

Division-induced DNA double strand breaks in the chromosome terminus region of Escherichia coli lacking RecBCD DNA repair enzyme

PubMed Central

Durand, Adeline; Desfontaines, Jean-Michel; Iurchenko, Ielyzaveta; Auger, Hélène; Leach, David R. F.

2017-01-01

Marker frequency analysis of the Escherichia coli recB mutant chromosome has revealed a deficit of DNA in a specific zone of the terminus, centred on the dif/TerC region. Using fluorescence microscopy of a marked chromosomal site, we show that the dif region is lost after replication completion, at the time of cell division, in one daughter cell only, and that the phenomenon is transmitted to progeny. Analysis by marker frequency and microscopy shows that the position of DNA loss is not defined by the replication fork merging point since it still occurs in the dif/TerC region when the replication fork trap is displaced in strains harbouring ectopic Ter sites. Terminus DNA loss in the recB mutant is also independent of dimer resolution by XerCD at dif and of Topo IV action close to dif. It occurs in the terminus region, at the point of inversion of the GC skew, which is also the point of convergence of specific sequence motifs like KOPS and Chi sites, regardless of whether the convergence of GC skew is at dif (wild-type) or a newly created sequence. In the absence of FtsK-driven DNA translocation, terminus DNA loss is less precisely targeted to the KOPS convergence sequence, but occurs at a similar frequency and follows the same pattern as in FtsK+ cells. Importantly, using ftsIts, ftsAts division mutants and cephalexin treated cells, we show that DNA loss of the dif region in the recB mutant is decreased by the inactivation of cell division. We propose that it results from septum-induced chromosome breakage, and largely contributes to the low viability of the recB mutant. PMID:28968392

SCRaMbLE generates designed combinatorial stochastic diversity in synthetic chromosomes.

PubMed

Shen, Yue; Stracquadanio, Giovanni; Wang, Yun; Yang, Kun; Mitchell, Leslie A; Xue, Yaxin; Cai, Yizhi; Chen, Tai; Dymond, Jessica S; Kang, Kang; Gong, Jianhui; Zeng, Xiaofan; Zhang, Yongfen; Li, Yingrui; Feng, Qiang; Xu, Xun; Wang, Jun; Wang, Jian; Yang, Huanming; Boeke, Jef D; Bader, Joel S

2016-01-01

Synthetic chromosome rearrangement and modification by loxP-mediated evolution (SCRaMbLE) generates combinatorial genomic diversity through rearrangements at designed recombinase sites. We applied SCRaMbLE to yeast synthetic chromosome arm synIXR (43 recombinase sites) and then used a computational pipeline to infer or unscramble the sequence of recombinations that created the observed genomes. Deep sequencing of 64 synIXR SCRaMbLE strains revealed 156 deletions, 89 inversions, 94 duplications, and 55 additional complex rearrangements; several duplications are consistent with a double rolling circle mechanism. Every SCRaMbLE strain was unique, validating the capability of SCRaMbLE to explore a diverse space of genomes. Rearrangements occurred exclusively at designed loxPsym sites, with no significant evidence for ectopic rearrangements or mutations involving synthetic regions, the 99% nonsynthetic nuclear genome, or the mitochondrial genome. Deletion frequencies identified genes required for viability or fast growth. Replacement of 3' UTR by non-UTR sequence had surprisingly little effect on fitness. SCRaMbLE generates genome diversity in designated regions, reveals fitness constraints, and should scale to simultaneous evolution of multiple synthetic chromosomes. © 2016 Shen et al.; Published by Cold Spring Harbor Laboratory Press.

SCRaMbLE generates designed combinatorial stochastic diversity in synthetic chromosomes

PubMed Central

Shen, Yue; Stracquadanio, Giovanni; Wang, Yun; Yang, Kun; Mitchell, Leslie A.; Xue, Yaxin; Cai, Yizhi; Chen, Tai; Dymond, Jessica S.; Kang, Kang; Gong, Jianhui; Zeng, Xiaofan; Zhang, Yongfen; Li, Yingrui; Feng, Qiang; Xu, Xun; Wang, Jun; Wang, Jian; Yang, Huanming; Boeke, Jef D.; Bader, Joel S.

2016-01-01

Synthetic chromosome rearrangement and modification by loxP-mediated evolution (SCRaMbLE) generates combinatorial genomic diversity through rearrangements at designed recombinase sites. We applied SCRaMbLE to yeast synthetic chromosome arm synIXR (43 recombinase sites) and then used a computational pipeline to infer or unscramble the sequence of recombinations that created the observed genomes. Deep sequencing of 64 synIXR SCRaMbLE strains revealed 156 deletions, 89 inversions, 94 duplications, and 55 additional complex rearrangements; several duplications are consistent with a double rolling circle mechanism. Every SCRaMbLE strain was unique, validating the capability of SCRaMbLE to explore a diverse space of genomes. Rearrangements occurred exclusively at designed loxPsym sites, with no significant evidence for ectopic rearrangements or mutations involving synthetic regions, the 99% nonsynthetic nuclear genome, or the mitochondrial genome. Deletion frequencies identified genes required for viability or fast growth. Replacement of 3′ UTR by non-UTR sequence had surprisingly little effect on fitness. SCRaMbLE generates genome diversity in designated regions, reveals fitness constraints, and should scale to simultaneous evolution of multiple synthetic chromosomes. PMID:26566658

Deep ancestry of mammalian X chromosome revealed by comparison with the basal tetrapod Xenopus tropicalis.

PubMed

Mácha, Jaroslav; Teichmanová, Radka; Sater, Amy K; Wells, Dan E; Tlapáková, Tereza; Zimmerman, Lyle B; Krylov, Vladimír

2012-07-16

The X and Y sex chromosomes are conspicuous features of placental mammal genomes. Mammalian sex chromosomes arose from an ordinary pair of autosomes after the proto-Y acquired a male-determining gene and degenerated due to suppression of X-Y recombination. Analysis of earlier steps in X chromosome evolution has been hampered by the long interval between the origins of teleost and amniote lineages as well as scarcity of X chromosome orthologs in incomplete avian genome assemblies. This study clarifies the genesis and remodelling of the Eutherian X chromosome by using a combination of sequence analysis, meiotic map information, and cytogenetic localization to compare amniote genome organization with that of the amphibian Xenopus tropicalis. Nearly all orthologs of human X genes localize to X. tropicalis chromosomes 2 and 8, consistent with an ancestral X-conserved region and a single X-added region precursor. This finding contradicts a previous hypothesis of three evolutionary strata in this region. Homologies between human, opossum, chicken and frog chromosomes suggest a single X-added region predecessor in therian mammals, corresponding to opossum chromosomes 4 and 7. A more ancient X-added ancestral region, currently extant as a major part of chicken chromosome 1, is likely to have been present in the progenitor of synapsids and sauropsids. Analysis of X chromosome gene content emphasizes conservation of single protein coding genes and the role of tandem arrays in formation of novel genes. Chromosomal regions orthologous to Therian X chromosomes have been located in the genome of the frog X. tropicalis. These X chromosome ancestral components experienced a series of fusion and breakage events to give rise to avian autosomes and mammalian sex chromosomes. The early branching tetrapod X. tropicalis' simple diploid genome and robust synteny to amniotes greatly enhances studies of vertebrate chromosome evolution.

Deep ancestry of mammalian X chromosome revealed by comparison with the basal tetrapod Xenopus tropicalis

PubMed Central

2012-01-01

Background The X and Y sex chromosomes are conspicuous features of placental mammal genomes. Mammalian sex chromosomes arose from an ordinary pair of autosomes after the proto-Y acquired a male-determining gene and degenerated due to suppression of X-Y recombination. Analysis of earlier steps in X chromosome evolution has been hampered by the long interval between the origins of teleost and amniote lineages as well as scarcity of X chromosome orthologs in incomplete avian genome assemblies. Results This study clarifies the genesis and remodelling of the Eutherian X chromosome by using a combination of sequence analysis, meiotic map information, and cytogenetic localization to compare amniote genome organization with that of the amphibian Xenopus tropicalis. Nearly all orthologs of human X genes localize to X. tropicalis chromosomes 2 and 8, consistent with an ancestral X-conserved region and a single X-added region precursor. This finding contradicts a previous hypothesis of three evolutionary strata in this region. Homologies between human, opossum, chicken and frog chromosomes suggest a single X-added region predecessor in therian mammals, corresponding to opossum chromosomes 4 and 7. A more ancient X-added ancestral region, currently extant as a major part of chicken chromosome 1, is likely to have been present in the progenitor of synapsids and sauropsids. Analysis of X chromosome gene content emphasizes conservation of single protein coding genes and the role of tandem arrays in formation of novel genes. Conclusions Chromosomal regions orthologous to Therian X chromosomes have been located in the genome of the frog X. tropicalis. These X chromosome ancestral components experienced a series of fusion and breakage events to give rise to avian autosomes and mammalian sex chromosomes. The early branching tetrapod X. tropicalis’ simple diploid genome and robust synteny to amniotes greatly enhances studies of vertebrate chromosome evolution. PMID:22800176

Computational model for chromosomal instabilty

NASA Astrophysics Data System (ADS)

Zapperi, Stefano; Bertalan, Zsolt; Budrikis, Zoe; La Porta, Caterina

2015-03-01

Faithful segregation of genetic material during cell division requires alignment of the chromosomes between the spindle poles and attachment of their kinetochores to each of the poles. Failure of these complex dynamical processes leads to chromosomal instability (CIN), a characteristic feature of several diseases including cancer. While a multitude of biological factors regulating chromosome congression and bi-orientation have been identified, it is still unclear how they are integrated into a coherent picture. Here we address this issue by a three dimensional computational model of motor-driven chromosome congression and bi-orientation. Our model reveals that successful cell division requires control of the total number of microtubules: if this number is too small bi-orientation fails, while if it is too large not all the chromosomes are able to congress. The optimal number of microtubules predicted by our model compares well with early observations in mammalian cell spindles. Our results shed new light on the origin of several pathological conditions related to chromosomal instability.

Trisomy 8 syndrome owing to isodicentric 8p chromosomes: regional assignment of a presumptive gene involved in corpus callosum development.

PubMed Central

Digilio, M C; Giannotti, A; Floridia, G; Uccellatore, F; Mingarelli, R; Danesino, C; Dallapiccola, B; Zuffardi, O

1994-01-01

Two patients with trisomy 8 syndrome owing to an isodicentric 8p;8p chromosome are described. Case 1 had a 46,XX/46,XX,-8,+idic(8)(p23) karyotype while case 2, a male, had the same abnormal karyotype without evidence of mosaicism. In situ hybridisation, performed in case 1, showed that the isochromosome was asymmetrical. Agenesis of the corpus callosum (ACC), which is a feature of trisomy 8 syndrome, was found in both patients. Although ACC is associated with aneuploidies for different chromosomes, a review of published reports indicates that, when associated with chromosome 8, this defect is the result of duplication of a gene located within 8p21-pter. Molecular analysis in one of our patients led us to exclude the distal 23 Mb of 8p from this ACC region. Images PMID:8014974

A novel locus for split-hand/foot malformation associated with tibial hemimelia (SHFLD syndrome) maps to chromosome region 17p13.1-17p13.3.

PubMed

Lezirovitz, Karina; Maestrelli, Sylvia Regina Pedrosa; Cotrim, Nelson Henderson; Otto, Paulo A; Pearson, Peter L; Mingroni-Netto, Regina Celia

2008-07-01

Split-hand/foot malformation (SHFM) associated with aplasia of long bones, SHFLD syndrome or Tibial hemimelia-ectrodactyly syndrome is a rare condition with autosomal dominant inheritance, reduced penetrance and an incidence estimated to be about 1 in 1,000,000 liveborns. To date, three chromosomal regions have been reported as strong candidates for harboring SHFLD syndrome genes: 1q42.2-q43, 6q14.1 and 2q14.2. We characterized the phenotype of nine affected individuals from a large family with the aim of mapping the causative gene. Among the nine affected patients, four had only SHFM of the hands and no tibial defects, three had both defects and two had only unilateral tibial hemimelia. In keeping with previous publications of this and other families, there was clear evidence of both variable expression and incomplete penetrance, the latter bearing hallmarks of anticipation. Segregation analysis and multipoint Lod scores calculations (maximum Lod score of 5.03 using the LINKMAP software) using all potentially informative family members, both affected and unaffected, identified the chromosomal region 17p13.1-17p13.3 as the best and only candidate for harboring a novel mutated gene responsible for the syndrome in this family. The candidate gene CRK located within this region was sequenced but no pathogenic mutation was detected.

Phylogeography of haplotypes of five microsatellites located in a low-recombination region of the X chromosome: studies worldwide and in Brazilian populations.

PubMed

Pereira, Rinaldo Wellerson; Pena, Sérgio D J

2006-01-01

We studied five microsatellites (DXS995, DXS8076, DXS8114, DXS1002 and DXS1050) located in a region of very low recombination rate in the long arm of the human X chromosome (Xq13.3-Xq21.3). No recombination was seen in 291 meioses in CEPH families. To test whether haplotypes composed of the five microsatellites could differentiate among distinct human continental populations, we studied an international panel containing 72 males from Africa, Europe, Asia and the America. Haplotypic diversity was very high within these groups and no haplotypes were shared among them. This led to the hope that we might be able to identify continent-specific lineages. However, in a median joining network there was no clear discrimination of the different continental groups. We then tested whether we could identify X chromosomal lineages from different continental origins in Brazilians. We typed 180 white Brazilians from four different geographical regions and examined their proportions of haplotype sharing with Africans, Asians, Europeans and Amerindians. No phylogeographical patterns emerged from the data. Moreover, there were several instances of the same haplotype being shared by many (and in one instance all) groups, suggesting that recombination might be occurring. We thus studied pairwise the level of linkage disequilibrium (LD) between the microsatellites. No detectable linkage disequilibrium between the most external loci DXS995 and DXS1050 was observed. Thus, even though recombination may be absent on short time spans, as seen in the CEPH pedigrees, on a long term basis it occurs often enough to dissipate all linkage disequilibrium. On the other hand, we observed very strong linkage disequilibrium between the pairs DXS995/DXS8076 and DXS1002/DXS8114, raising the possibility of resequencing the segment between them to identify single nucleotide polymorphisms (SNPs) in their intervals. The combination of X-linked microsatellites and SNPs in strong linkage disequilibrium might