Naturally occurring copy-number polymorphism in Drosophila melanogaster
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ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE9639 | GEO | 2008/03/20
SECONDARY ACCESSION(S): PRJNA103499
REPOSITORIES: GEO
Similar Datasets
Project description:The role natural selection plays in governing the locations and early evolution of copy number mutations remains largely unexplored. Here we employ high-density full-genome tiling arrays to create a fine-scale genomic map of copy number polymorphisms (CNPs) in Drosophila melanogaster. We inferred a total of 2,658 independent CNPs, 56% of which overlap genes. These include CNPs likely to be under positive selection, most notably high frequency duplications encompassing toxin-response genes. The locations and frequencies of CNPs are strongly shaped by purifying selection with deletions under stronger purifying selection than duplications. Among duplications, those overlapping exons or introns and those falling on the X-chromosome seem to be subject to the strongest purifying selection. In order to characterize copy number polymorphisms (CNPs) in Drosophila malanogaster, we applied comparative genome hybridization (CGH) using tiling arrays covering the full euchromatic genome of Drosophila melanogaster. We inferred copy number changes with a Hidden Markov Model (HMM) that returned the posterior probabilities for copy number by comparing DNA hybridization intensities between natural isolates and the reference genome strain. Training data for copy number changes were obtained via hybridization with a line known to contain a ~200kb homozygous duplication and from a set of 52 validated homozygous deletions. The probabilities of mutation were parsed to make CNP calls. Key words: comparative genomic hybridization, CGH, copy number polymorphism, CNP, copy number variation, CNV, duplication, deletion
2008-06-06 | GSE11326 | GEO
Project description:Copy number variants (CNVs) can reach appreciable frequencies in the human population, and several of these copy number polymorphisms (CNPs) have been recently associated with human diseases including lupus, psoriasis, Crohn disease, and obesity. Despite new advances, significant biases remain in terms of CNP discovery and genotyping. Developing a novel method based on single channel intensity data and benchmarking against copy numbers determined from sequencing read-depth, we successfully obtained CNP genotypes for 1489 CNPs from 487 human DNA samples from diverse ethnic backgrounds. This customized microarray was enriched for segmental duplication-rich regions and novel insertions of sequences not represented in the reference genome assembly or on standard single nucleotide polymorphism (SNP) microarray platforms. We observe that CNPs in segmental duplications are more likely to be population differentiated than CNPs in unique regions (p = 0.015) and that bi-allelic CNPs show greater stratification when compared to frequency-matched SNPs (p = 0.0026). Although bi-allelic CNPs show a strong correlation of copy number with flanking SNP genotypes, the majority of multi-copy CNPs do not (40% with r >0.8). We selected a subset of CNPs for further characterization in 1873 additional samples from 62 populations (947 samples analyzed by microarray; 926 samples analyzed with PCR based assays); this revealed striking population-differentiated structural variants in genes of clinical significance such as the OCLN gene, a tight junction protein involved in hepatitis C viral entry. Our new microarray design allows these variants to be rapidly tested for disease association and our results suggest that CNPs (especially those that are not in linkage disequilibrium with SNPs) may have contributed disproportionately to human diversity and selection.
2011-02-01 | GSE26450 | GEO
Project description:We have performed a genome wide analysis of gene copy number polymorphisms and report here for the first time that the human genome contains thousands of well-characterized genes at copy numbers different from one maternal and one paternal allele; and that, furthermore, the copy numbers of hundreds of well-characterized genes can vary between two normal healthy humans making this a major source of genetic variation. Groups of genes affected by CNPs include genes involved in signal transduction, oncogenesis, cell adhesion activity and several types of immune response. In contrast to SNPs, which preferentially affect non-coding regions of the genome, copy number polymorphisms of well-characterized and actively expressed genes are very likely to have important biological consequences. Keywords: Gene Copy Number Variation
2006-07-01 | GSE4981 | GEO
Project description:Genetic variation amongst individual humans occurs on many different scales, ranging from gross alterations in the human karyotype to single-nucleotide changes. In this manuscript we explore variation on an intermediate scale-particularly insertions, deletions, and inversions affecting from a few thousand to a few million base pairs. We employed a clone-based method to interrogate this intermediate structural variation in eight individuals of diverse geographic ancestry. Our analysis provides a comprehensive overview of the normal pattern of structural variation present in these genomes, refining the location of 1695 structural variants. We find that 50% were seen in more than one individual and that nearly half lay outside regions of the genome previously described as structurally variant. We discover 525 new insertion sequences that are not present in the human reference genome and show that many of these are variable in copy number among individuals. Sequencing of a subset of structural variants reveals considerable locus complexity and provides insights into the different mutational processes that have shaped the human genome. These data provide the first high-resolution sequence-map of human structural variation-an important standard for genotyping platforms and a prelude to future individual genome sequencing projects. Keywords: comparitive genomic hybridization, copy number variation, structural variation, fosmid end sequencing
2008-05-01 | GSE10037 | GEO
Project description:Genetic variation amongst individual humans occurs on many different scales, ranging from gross alterations in the human karyotype to single-nucleotide changes. In this manuscript we explore variation on an intermediate scale-particularly insertions, deletions, and inversions affecting from a few thousand to a few million base pairs. We employed a clone-based method to interrogate this intermediate structural variation in eight individuals of diverse geographic ancestry. Our analysis provides a comprehensive overview of the normal pattern of structural variation present in these genomes, refining the location of 1695 structural variants. We find that 50% were seen in more than one individual and that nearly half lay outside regions of the genome previously described as structurally variant. We discover 525 new insertion sequences that are not present in the human reference genome and show that many of these are variable in copy number among individuals. Sequencing of a subset of structural variants reveals considerable locus complexity and provides insights into the different mutational processes that have shaped the human genome. These data provide the first high-resolution sequence-map of human structural variation-an important standard for genotyping platforms and a prelude to future individual genome sequencing projects. Keywords: comparitive genomic hybridization, copy number variation, structural variation, fosmid end sequencing CGH analysis targeted against sites identified by fosmid end sequencing. 8 HapMap samples (sources of libraries ABC7-ABC14) are hybed against NA15510 (source of fosmid library G248).
2008-05-01 | E-GEOD-10037 | biostudies-arrayexpress
Project description:We have performed a genome wide analysis of gene copy number polymorphisms and report here for the first time that the human genome contains thousands of well-characterized genes at copy numbers different from one maternal and one paternal allele; and that, furthermore, the copy numbers of hundreds of well-characterized genes can vary between two normal healthy humans making this a major source of genetic variation. Groups of genes affected by CNPs include genes involved in signal transduction, oncogenesis, cell adhesion activity and several types of immune response. In contrast to SNPs, which preferentially affect non-coding regions of the genome, copy number polymorphisms of well-characterized and actively expressed genes are very likely to have important biological consequences. Experiment Overall Design: We utilized an expression microarray to analyze gene copy number variations (GCNVs).
2008-06-13 | E-GEOD-4981 | biostudies-arrayexpress
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. To determine copy number variation, the genomic DNA from five homozygous and two heterozygous second chromosome substitution lines were extracted and compared to another second chromosome substitution line. Gene expression levels can be referred to at Series GSE12191 (Lemos et al. (2008) PMID:18791071).
2011-03-03 | E-GEOD-27632 | biostudies-arrayexpress
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:High-grade serous ovarian carcinoma (HGSOC) is the most genomically complex cancer, characterised by ubiquitous TP53 mutation, profound structural variation and heterogeneity. Multiple mutational processes driving chromosomal instability can be distinguished by specific copy number signatures. To develop clinically relevant models of these mutational processes we derived 15 continuous HGSOC patient-derived organoids (PDOs) and provide detailed transcriptomic and genomic profiles using shallow whole genome sequencing single cell and bulk analysis. We show that PDOs comprise communities of different clonal populations and represent models of CCNE1 amplification, chromothripsis, tandem-duplicator phenotype and whole genome duplication. PDOs can also be used as exploratory tools to study transcriptional effects of copy number alterations as well as compound-sensitivity tests. In summary, HGSOC PDO cultures provide a genomic tool for studies of specific mutational processes and precision therapeutics.
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Project description:Genetic variation amongst individual humans occurs on many different scales, ranging from gross alterations in the human karyotype to single-nucleotide changes. In this manuscript we explore variation on an intermediate scale-particularly insertions, deletions, and inversions affecting from a few thousand to a few million base pairs. We employed a clone-based method to interrogate this intermediate structural variation in eight individuals of diverse geographic ancestry. Our analysis provides a comprehensive overview of the normal pattern of structural variation present in these genomes, refining the location of 1695 structural variants. We find that 50% were seen in more than one individual and that nearly half lay outside regions of the genome previously described as structurally variant. We discover 525 new insertion sequences that are not present in the human reference genome and show that many of these are variable in copy number among individuals. Sequencing of a subset of structural variants reveals considerable locus complexity and provides insights into the different mutational processes that have shaped the human genome. These data provide the first high-resolution sequence-map of human structural variation-an important standard for genotyping platforms and a prelude to future individual genome sequencing projects. Keywords: comparative genomic hybridization
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