Project description:We carried out a high throughput analysis of insulin-induced kinase signaling pathways in primary fibroblasts from 35 unrelated individuals. We found that extensive individual variation exists in induction of various signaling pathways. ERK signaling displayed the greatest variation, which led to extensive variation in expression of downstream target genes. Our results suggest that phenotypic variation in kinase signaling mediates variation in downstream processes of insulin response. Future study of such phenotypic variation is important to linking genetic variants to individual susceptibility to complex diseases such as diabetes.
Project description:Copy number variants (CNVs) affect both disease and normal phenotypic variation but those lying within heavily duplicated, highly identical sequence have been difficult to assay. By analyzing short-read mapping depth for 159 human genomes, we demonstrate accurate estimation of absolute copy number for duplications as small as 1.9 kbp, ranging from 0-48 copies. We identified 4.1 million ‘singly unique nucleotide’ (SUN) positions informative in distinguishing specific copies, and use them to genotype the copy and content of specific paralogs within highly duplicated gene families. These data identify human-specific expansions in genes associated with brain development, reveal extensive population genetic diversity, and detect signatures consistent with gene conversion in the human species. Our approach makes ~1000 genes accessible to genetic studies of disease association. This dataset complements the results from short read sequencing by performing validation on five individuals. We analyzed the 17q21.1 locus in 5 HapMap individuals by array CGH on a custom Agilent 4-plex 310k array performing 1 experiment for each sample. This array was targeted at high density (1 probe/105bp) to 7 genomic loci, including 17q21. The reference individual used was NA19240.
Project description:Copy number variants (CNVs) affect both disease and normal phenotypic variation but those lying within heavily duplicated, highly identical sequence have been difficult to assay. By analyzing short-read mapping depth for 159 human genomes, we demonstrate accurate estimation of absolute copy number for duplications as small as 1.9 kbp, ranging from 0-48 copies. We identified 4.1 million ‘singly unique nucleotide’ (SUN) positions informative in distinguishing specific copies, and use them to genotype the copy and content of specific paralogs within highly duplicated gene families. These data identify human-specific expansions in genes associated with brain development, reveal extensive population genetic diversity, and detect signatures consistent with gene conversion in the human species. Our approach makes ~1000 genes accessible to genetic studies of disease association.
Project description:Staphylococcus aureus causes disease in humans and a wide array of animals. Of note, S. aureus mastitis of ruminants, including cows, sheep and goats, results in major economic losses worldwide. Extensive variation in genome content exists among S. aureus pathogenic clones. However, the genomic variation among S. aureus strains infecting different animal species has not been well examined. To investigate variation in the genome content of human and ruminant S. aureus we carried out whole genome PCR scanning (WGPS), comparative genomic hybridizations (CGH), and directed DNA sequence analysis of strains of human, bovine, ovine, and caprine origin. Extensive variation in genome content was discovered including host- and ruminant-specific genetic loci. Ovine and caprine strains were genetically allied whereas bovine strains were heterogenous in gene content. As expected, mobile genetic elements such as pathogenicity islands and bacteriophages contributed to the variation in genome content between strains. However, remarkably, most host-specific differences were restricted to regions of the conserved core genome, which contained allelic variation in genes encoding proteins of known and unknown function. Many of these proteins are predicted to be exported and could play a role in host-pathogen interactions. These data suggest that diversification of the core genome may be more important than acquisition of novel genes for S. aureus host-adaptation. The host-specific determinants identified by the whole-genome approaches adopted in the current study represent excellent targets for studies of the evolution and molecular basis of S. aureus host specificity. Keywords: Strain vs strain eleven strains of Sa were compared at the DNA level in triplicate.
Project description:Staphylococcus aureus causes disease in humans and a wide array of animals. Of note, S. aureus mastitis of ruminants, including cows, sheep and goats, results in major economic losses worldwide. Extensive variation in genome content exists among S. aureus pathogenic clones. However, the genomic variation among S. aureus strains infecting different animal species has not been well examined. To investigate variation in the genome content of human and ruminant S. aureus we carried out whole genome PCR scanning (WGPS), comparative genomic hybridizations (CGH), and directed DNA sequence analysis of strains of human, bovine, ovine, and caprine origin. Extensive variation in genome content was discovered including host- and ruminant-specific genetic loci. Ovine and caprine strains were genetically allied whereas bovine strains were heterogenous in gene content. As expected, mobile genetic elements such as pathogenicity islands and bacteriophages contributed to the variation in genome content between strains. However, remarkably, most host-specific differences were restricted to regions of the conserved core genome, which contained allelic variation in genes encoding proteins of known and unknown function. Many of these proteins are predicted to be exported and could play a role in host-pathogen interactions. These data suggest that diversification of the core genome may be more important than acquisition of novel genes for S. aureus host-adaptation. The host-specific determinants identified by the whole-genome approaches adopted in the current study represent excellent targets for studies of the evolution and molecular basis of S. aureus host specificity. Keywords: Strain vs strain
Project description:Long interspersed element-1 (L1) retrotransposons constitute the largest transposable element (TE) family in mammalian genomes and contribute prominently to inter- and intra-individual genetic variation. Although most L1 elements are inactive, some evolutionary younger insertions remain intact and genetically competent for transcription and occasionally retrotransposition. Despite being generally more abundant in gene-poor regions, intact or full-length L1s (FL-L1) are also enriched around specific classes of genes and on the X chromosome. How proximal FL-L1 may affect nearby gene expression remains unclear. Here, we examine this systematically using engineered mouse embryonic stem cells (ESCs) in which expression of one active L1 subfamily is perturbed. We found that FL-L1 activation leads to the misregulation of ~1,024 genes, whereas FL-L1 repression affects ~81 genes. In most cases, misexpressed genes contain an intronic FL-L1 or lie near a FL-L1 (<260 kb). Gene ontology analysis shows that upon L1 activation, upregulated genes are enriched for neuronal function-related terms, suggesting that some L1 elements may have evolved to control neuronal gene networks. These results illustrate the cis-regulatory potential of FL-L1 elements and suggest a broader role for L1s than originally anticipated.
Project description:We carried out a high throughput analysis of insulin-induced kinase signaling pathways in primary fibroblasts from 35 unrelated individuals. We found that extensive individual variation exists in induction of various signaling pathways. ERK signaling displayed the greatest variation, which led to extensive variation in expression of downstream target genes. Our results suggest that phenotypic variation in kinase signaling mediates variation in downstream processes of insulin response. Future study of such phenotypic variation is important to linking genetic variants to individual susceptibility to complex diseases such as diabetes. Passage-matched primary fibroblasts from 35 unrelated newborns (foreskin) were treated with 100 nM insulin. We measured gene expression levels in each of 35 individuals at baseline, and 1 hour and 6 hours after insulin treatment using expression arrays. In order to examine effects of ERK inhibition on insulin-induced gene expression, we treated fibroblasts from 4 individuals with DMSO or 10uM of U0126 for 1 hour, followed by insulin treatment for one hour and 6 hours. We then harvested cells and measured gene expression in each sample using expression arrays.
Project description:To study the evolutionary dynamics of regulatory DNA, we mapped >1.3 million deoxyribonuclease I–hypersensitive sites (DHSs) in 45 mouse cell and tissue types, and systematically compared these with human DHS maps from orthologous compartments. We found that the mouse and human genomes have undergone extensive cis-regulatory rewiring that combines branch-specific evolutionary innovation and loss with widespread repurposing of conserved DHSs to alternative cell fates, and that this process is mediated by turnover of transcription factor (TF) recognition elements. Despite pervasive evolutionary remodeling of the location and content of individual cis-regulatory regions, within orthologous mouse and human cell types the global fraction of regulatory DNA bases encoding recognition sites for each TF has been strictly conserved. Our findings provide new insights into the evolutionary forces shaping mammalian regulatory DNA landscapes.
Project description:Copy number variants (CNVs) represent a substantial source of genomic variation in vertebrates, but the zebrafish reference genome has no annotated CNV information. We developed a zebrafish CNV map using 80 zebrafish genomes from laboratory strains (AB, Tubingen, and WIK) and one native population, identifying 6,080 CNV elements. Overlapping or adjacent CNVs account for 14.6% of the genome, representing four times the CNV levels from other vertebrates including humans. Highest intra-specific CNV levels were observed for Tubingen, a common laboratory strain due to high fecundity. Tubingen variation likely represents higher initial population size and composite population founders initiating the laboratory strain. Extensive zebrafish CNVs, along with associated phenotypic impacts, advocates for increased usage of isogenic strains for genetic studies intended for human disease translation.? 19 zebrafish from 3 laboratory strains and one native population were analyzed using a strain specific reference for each group