The fine-scale and complex architecture of human copy number variation
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE9831 | GEO | 2008/01/24
SECONDARY ACCESSION(S): PRJNA103801
REPOSITORIES: GEO
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Project description:Despite considerable excitement over the potential functional significance of copy number variants (CNVs), we still lack knowledge of the fine-scale architecture of the large majority of CNV regions in the human genome. In this study, we used a high-resolution array-based comparative genomic hybridization (aCGH) platform that targeted known CNV regions of the human genome at ~1 kb resolution to interrogate the genomic DNAs of 30 individuals from four HapMap populations. Our results revealed that 1,020 of 1,153 CNV loci (88%) were actually smaller in size than what is recorded in the Database of Genomic Variants based on previously published studies. A reduction in size of more than 50% was observed for 876 CNV regions (76%). We conclude that the total genomic content of common human CNVs may be smaller than previously thought. In addition, approximately 8% of the CNV regions observed in multiple individuals exhibited genomic architectural complexity in the form of smaller CNVs within larger ones and CNVs with inter-individual variation in breakpoints. Future association studies that aim to capture the potential influences of CNVs on disease phenotypes will need to consider how to best ascertain this previously underappreciated complexity. The DNA samples are a panel of 30 Hapmap samples, and a female sample NA15510 of undetermined geographic origin, which has been well characterized by fosmid-end sequencing (Tuzun et al. 2005, Nature Genetics 10, p1038). The DNA for this set of 16 female and 15 male samples are all supplied by the Coriell Cell Repository, and is comprised of samples from four populations: 10 unrelated Yoruban, 10 unrelated European-American individuals from Utah (CEPH), 5 unrelated Chinese, and 5 unrelated Japanese. The reference sample, NA10851 is also a male CEPH also from the HapMap Sample set (Corriel Cell Repository). Each of these samples was hybridized in pairs with the reversed labeling polarities. Additionally, 3 self-self control hybridizations were carried out for the reference sample, NA10851, one on each hybridization date. In the Title for each of the samples, each hybridization session is indicated by the letters A, B or C.
2008-01-23 | E-GEOD-9831 | biostudies-arrayexpress
Project description:Chromosomal segmental copy number variation (CNV) has been recently recognized as a very important source of genetic variability. Some CNV loci involve genes or conserved regulatory regions. Compelling evidence indicates that CNVs impact genome functions. The chicken is a very important farm animal species which has also served as model animal for biological and biomedical research for hundreds of years. A map of CNVs in chickens could facilitate the identification of chromosome regions that segregate for important agricultural and disease phenotypes. NimbleGen 385k whole genome tiling arrays were used to map CNVs in the chicken. This study has identified 96 CNVs in three lines of chickens (broiler, Leghorn and Rhode Island red). These CNVs encompass 16 Mb (1.3%) of the chicken genome. Twenty six CNVs were found in two or more animals. Smaller sized CNVs mostly affect none coding sequences while larger CNV regions involve genes, for example prolactin receptor, aldose reductase and zinc finger proteins, suggesting chicken CNVs potentially affect agricultural or disease related traits.
2010-06-11 | GSE19469 | GEO
Project description:A database of apparently benign copy number variants (bCNVs) detected by a Spectral Genomics Inc./PerkinElmer BAC array platform has been maintained through the University of Utah Comparative Genomic Hybridization laboratory since 2005. The target population for this database represents 1275 patients with abnormal phenotypes, primarily children referred for developmental delay and mental retardation. These bCNVs are independent of any identified copy number abnormality detected. The most common 35 bCNVs observed and their frequencies are reported here, and a subset of ten of the patients studied was evaluated on a new oligonucleotide CNV array set designed by Agilent Technologies. There was a 76% concordance of calls detected by both array platforms in the same patients; the discordant regions may be due to differences in reference DNAs, or false positive/negative results on either array. The higher resolution of the Agilent oligonucleotide array compared to the BAC array allowed for further characterization to determine precise breakpoints of the observed CNVs, in addition to documenting additional CNVs of smaller sizes. As expected, observed CNVs and their frequencies were generally consistent with those of other previously published and available databases, including the Database of Genomic Variants (http://projects.tcag.ca/variation/). The availability of these data should assist other clinical laboratories in the evaluation of CNVs of unknown clinical significance. The Cytogenetics Laboratory at the University of Utah has been using aCGH to evaluate DNA derived from blood of patients with developmental delay, mental retardation and “syndromic” or dysmorphic phenotypes since 2005. From this database, we were able to determine which clones represented sequences which were frequently deleted or duplicated in our patient population. We identified our most common CNV regions and then selected DNAs from ten patients who exhibited copy number changes of those common regions for further study with the Agilent CNV microarray set. Normal male or female DNA from Promega was used as a sex-mismatched control. In addition to the ten clinical specimens, two self-self experiments for two patient samples were analyzed to estimate a false positive rate and to fine tune the parameters used for data analysis. A replicate hybridization was performed on one patient to determine reproducibility.
2008-08-31 | E-GEOD-11815 | biostudies-arrayexpress
Project description:Copy number variants (CNVs) are heritable gains and losses of genomic DNA in normal individuals. While copy number variation is widely studied in humans, our knowledge of CNVs in other mammalian species is more limited. We have designed a custom array-based comparative genomic hybridization (aCGH) platform with 385,000 oligonucleotide probes based on the reference genome sequence of the rhesus macaque (Macaca mulatta), the most widely studied non-human primate in biomedical research. We used this platform to identify 123 CNVs among 10 unrelated macaque individuals, with 24% of the CNVs observed in multiple individuals. We found that segmental duplications were significantly enriched at macaque CNV loci. We also observed significant overlap between rhesus macaque and human CNVs, suggesting that certain genomic regions are prone to recurrent CNV formation and instability, even across a total of ~50 million years of primate evolution (~25 million years in each lineage). Furthermore, for 8 of the CNVs that were observed in both humans and macaques, previous human studies have reported a relationship between copy number and gene expression or disease susceptibility. Therefore, the rhesus macaque offers an intriguing, non-human primate model organism for which hypotheses concerning the specific functions of phenotypically-relevant human CNVs can be tested. Keywords: array-based comparative genomic hybridization, oligonucleotide probes
2008-01-15 | GSE9220 | GEO
Project description:A database of apparently benign copy number variants (bCNVs) detected by a Spectral Genomics Inc./PerkinElmer BAC array platform has been maintained through the University of Utah Comparative Genomic Hybridization laboratory since 2005. The target population for this database represents 1275 patients with abnormal phenotypes, primarily children referred for developmental delay and mental retardation. These bCNVs are independent of any identified copy number abnormality detected. The most common 35 bCNVs observed and their frequencies are reported here, and a subset of ten of the patients studied was evaluated on a new oligonucleotide CNV array set designed by Agilent Technologies. There was a 76% concordance of calls detected by both array platforms in the same patients; the discordant regions may be due to differences in reference DNAs, or false positive/negative results on either array. The higher resolution of the Agilent oligonucleotide array compared to the BAC array allowed for further characterization to determine precise breakpoints of the observed CNVs, in addition to documenting additional CNVs of smaller sizes. As expected, observed CNVs and their frequencies were generally consistent with those of other previously published and available databases, including the Database of Genomic Variants (http://projects.tcag.ca/variation/). The availability of these data should assist other clinical laboratories in the evaluation of CNVs of unknown clinical significance.
2008-08-31 | GSE11815 | GEO
Project description:Background: Detecting genetic variation is a critical step in elucidating the molecular mechanisms underlying phenotypic diversity. Until recently, such detection has mostly focused on single nucleotide polymorphisms (SNPs) because of the ease in screening complete genomes. Another type of variant, copy number variation (CNV), is emerging as a significant contributor to phenotypic variation in many species. Here we describe a genome-wide CNV study using array comparative genomic hybridization (aCGH) in a wide variety of chicken breeds. Results: We identified 3,154 CNVs, grouped into 1,556 CNV regions (CNVRs). Thirty percent of the CNVs were detected in at least 2 individuals. The average size of the CNVs detected was 46.3 kb with the largest CNV, located on GGAZ, being 4.3 Mb. Approximately 75% of the CNVs are copy number losses relatively to the Red Jungle Fowl reference genome. The genome coverage of CNVRs in this study is 60 Mb, which represents almost 5.4% of the chicken genome. In particular large gene families such as the keratin gene family and the MHC show extensive CNV. Conclusions: A relative large group of the CNVs are line-specific, several of which were previously shown to be related to the causative mutation for a number of phenotypic variants. The chance that inter-specific CNVs fall into CNVRs detected in chicken is related to the evolutionary distance between the species. Our results provide a valuable resource for the study of genetic and phenotypic variation in this phenotypically diverse species.
2013-08-21 | GSE47623 | GEO
Project description:Copy number variants (CNVs) reshape gene structure, modulate gene expression, and contribute to significant phenotypic variation. Previous studies have revealed CNV patterns in natural populations of Drosophila melanogaster and suggested that selection and mutational bias shape genomic patterns of CNV. While previous CNV studies focused on heterogeneous strains, here we established a number of second-chromosome substitution lines to uncover CNV characteristics when homozygous. The percentage of genes harboring CNVs is higher than found in previous studies. More CNVs are detected in homozygous than heterozygous substitution strains, suggesting the comparative genomic hybridization arrays underestimate CNV owing to heterozygous masking. We incorporated previous gene expression data collected from some of the same substitution lines to investigate relationships between CNV gene dosage and expression. Most genes present in CNVs show no evidence of increased or diminished transcription, and the fraction of such dosage-insensitive CNVs is greater in heterozygotes. More than 70% of the dosage-sensitive CNVs are recessive with undetectable effects on transcription in heterozygotes. A deficiency of singletons in recessive dosage-sensitive CNVs supports the hypothesis that most CNVs are subject to negative selection. On the other hand, relaxed purifying selection might account for the higher number of protein-protein interactions in dosage insensitive CNVs than in dosage-sensitive CNVs. Dosage-sensitive CNVs that are up-regulated and down-regulated coincide with copy number increases and decreases. Our results help clarify the relation between CNV dosage and gene expression in the D. melanogaster genome.
2011-03-03 | GSE27632 | GEO
Project description:Submicroscopic (< 2 Mb) segmental DNA copy number changes are a recently recognized source of genetic variability between individuals. The biological consequences of copy number variants (CNVs) are largely undefined. CNVs have been detected in diverse species, including mice and humans. Published studies in mice have been limited by resolution and strain selection. We chose to study twenty-one well-characterized inbred mouse strains that are the focus of an international effort to measure, catalog, and disseminate phenotype data. We performed comparative genomic hybridization using long oligomer arrays (oligo-aCGH) to characterize CNVs in these strains. This technique increased the resolution of CNV detection by more than an order of magnitude over previous methodologies. The CNVs range in size from 21-2,002 kb. Clustering strains by CNV profile recapitulates aspects of the known ancestry of these strains. Most of the CNVs (77.5%) contain annotated genes. We demonstrate that this technique can identify copy number differences associated with known polymorphic traits. The phenotype of previously uncharacterized strains can be predicted based on their copy number at these loci. Annotation of CNVs in the mouse genome combined with sequence-based analysis provides an important resource that will help define the genetic basis of complex traits. Keywords: array comparative genomic hybridization (aCGH)
2006-11-21 | GSE5805 | GEO
Project description:Goal: To identify copy number variation in normal individuals using high density, non-polymorphic oligonucleotide probes Background DNA sequence diversity within the human genome may be more greatly affected by copy number variations (CNVs) than single nucleotide polymorphisms (SNPs). Although the importance of CNVs in genome wide association studies (GWAS) is becoming widely accepted, the optimal methods for identifying these variants are still under evaluation. We have previously reported a comprehensive view of CNVs in the HapMap DNA collection using high density 500K EA (Early Access) SNP genotyping arrays which revealed greater than 1,000 CNVs ranging in size from 1kb to over 3Mb. Although the arrays used most commonly for GWAS predominantly interrogate SNPs, CNV identification and detection does not necessarily require the use of DNA probes centered on polymorphic nucleotides and may even be hindered by the dependence on a successful SNP genotyping assay. Results In this study, we have designed and evaluated a high density array predicated on the use of non-polymorphic oligonucleotide probes for CNV detection. This approach effectively uncouples copy number detection from SNP genotyping and thus has the potential to significantly improve probe coverage for genome-wide CNV identification. This array, in conjunction with PCR-based, complexity-reduced DNA target, queries over 1.3M independent NspI restriction enzyme fragments in the 200bp to 1100bp size range, which is a several fold increase in marker density as compared to the 500K EA array. In addition, a novel algorithm was developed and validated to extract CNV regions and boundaries. Conclusions Using a well-characterized pair of DNA samples, close to 200 CNVs were identified, of which nearly 50% appear novel yet were independently validated using quantitative PCR. The results indicate that non-polymorphic probes provide a robust approach for CNV identification, and the increasing precision of CNV boundary delineation should allow a more complete analysis of their genomic organization. A set of five genomic DNA samples containing different numbers of X chromosomes (1X to 5X sample set, including NA15510 and NA10851) were hybridized to Nsp copy number (CN) arrays in triplicate to evaluate detection of copy number variation using high density, non-polymorphic oligonucleotide probes. 6 Hapmap samples were hybridized to Nsp CN arrays to evaluate Mendelian inheritance of CNVs.
2008-04-24 | E-GEOD-9053 | biostudies-arrayexpress
Project description:CNV plays an important role in the chicken genomic studies,it is imperative need to investigate the extent and pattern of CNVs using array comparative genomic hybridization (aCGH) in chinese chicken breeds for future studies associating phenotype to genome architecture. we describe systematic and genome-wide analysis of CNVs loci in five Chinese indigenous chicken breeds were evaluated by aCGH.
2014-10-10 | GSE49889 | GEO