Project description:The identity of most functional elements in the mammalian genome and the phenotypes they impact are unclear. Here, we perform a genome-wide comparative analysis of patterns of accelerated evolution in species with highly distinctive traits to discover candidate functional elements for clinically important phenotypes. We identify accelerated regions (ARs) in the elephant, hibernating bat, orca, dolphin, naked mole rat and thirteen-lined ground squirrel lineages in mammalian conserved regions, uncovering ~33,000 elements that bind hundreds of different regulatory proteins in humans and mice. ARs in the elephant, the largest land mammal, are uniquely enriched at elephant DNA damage response genes and changed conserved regulatory sites. The genomic hotspot for elephant ARs is the E3 ligase subunit of the Fanconi Anemia Complex, a master regulator of DNA repair. Additionally, ARs in the six species are associated with specific human clinical phenotypes that have apparent concordance with overt traits in each species.
2018-01-01 | GSE107117 | GEO
Project description:Annotation of the Asian Elephant Genome - Myanmar Elephant Genome Project
Project description:The model organism Encyclopedia of DNA Elements project (modENCODE) has produced a comprehensive annotation of D. melanogaster transcript models based on an enormous amount of high-throughput experimental data. However, some transcribed elements may not be functional, and technical artifacts may lead to erroneous inference of transcription. Inter-species comparison provides confidence to predicted annotation, since transcriptional activity that has been evolutionarily conserved is likely to have an advantageous function. We have performed RNA-Seq and CAGE-Seq experiments on more than 80 samples from multiple tissues and stages of 15 Drosophila species, including 8 previously unsequenced genomes. We have found strikingly conserved sequence, expression, and splicing for the vast majority of transcript models in modENCODE annotation (e.g. 99% exons of coding sequences (CDS), 88% exons of untranslated regions (UTR), and 87% splicing events), indicating that the transcriptome annotation is of very high quality. We also describe dynamic transcriptome evolution within the Drosophila genus, including conserved promoter structure, labile positions of transcription start sites, and rapidly evolving RNA-editing events. We demonstrate how this phylogenetic approach to DNA element validation will prove useful in the annotation of other high priority genomes, especially for genomes that are less compact than Drosophila (e.g. the vast majority of vertebrate genomes). Refer to individual Series (listed below).
Project description:The model organism Encyclopedia of DNA Elements project (modENCODE) has produced a comprehensive annotation of D. melanogaster transcript models based on an enormous amount of high-throughput experimental data. However, some transcribed elements may not be functional, and technical artifacts may lead to erroneous inference of transcription. Inter-species comparison provides confidence to predicted annotation, since transcriptional activity that has been evolutionarily conserved is likely to have an advantageous function. We have performed RNA-Seq and CAGE-Seq experiments on more than 80 samples from multiple tissues and stages of 15 Drosophila species, including 8 previously unsequenced genomes. We have found strikingly conserved sequence, expression, and splicing for the vast majority of transcript models in modENCODE annotation (e.g. 99% exons of coding sequences (CDS), 88% exons of untranslated regions (UTR), and 87% splicing events), indicating that the transcriptome annotation is of very high quality. We also describe dynamic transcriptome evolution within the Drosophila genus, including conserved promoter structure, labile positions of transcription start sites, and rapidly evolving RNA-editing events. We demonstrate how this phylogenetic approach to DNA element validation will prove useful in the annotation of other high priority genomes, especially for genomes that are less compact than Drosophila (e.g. the vast majority of vertebrate genomes).
Project description:Background Methylation of CG dinucleotides constitutes a critical system of epigenetic memory in bony vertebrates, where it modulates gene expression and suppresses transposon activity. The genomes of studied vertebrates are pervasively hypermethylated, with the exception of regulatory elements such as transcription start sites (TSSs), where the presence of methylation is associated with gene silencing. This system is not found in the sparsely methylated genomes of invertebrates, and establishing how it arose during early vertebrate evolution is impeded by a paucity of epigenetic data from basal vertebrates. Methods We perform whole-genome bisulfite sequencing to generate the first genome-wide methylation profiles of a cartilaginous fish, the elephant shark Callorhinchus milii. Employing these to determine the elephant shark methylome structure and its relationship with expression, we compare this with higher vertebrates and an invertebrate chordate using published methylation and transcriptome data. Results Like higher vertebrates, the majority of elephant shark CG sites are highly methylated, and methylation is abundant across the genome rather than patterned in the mosaic configuration of invertebrates. This global hypermethylation includes transposable elements and the bodies of genes at all expression levels. Significantly, we document an inverse relationship between TSS methylation and expression in the elephant shark, supporting the presence of the repressive regulatory architecture shared by higher vertebrates. Conclusions Our demonstration that methylation patterns in a cartilaginous fish are characteristic of higher vertebrates imply the conservation of this epigenetic modification system across jawed vertebrates separated by 465 million years of evolution. In addition, these findings position the elephant shark as a valuable model to explore the evolutionary history and function of vertebrate methylation.
Project description:Gene regulatory elements are central drivers of phenotypic variation and thus of critical importance towards understanding the genetics of complex traits. Here we present a genome-wide annotation of regulatory elements in a non-mammalian vertebrate, chicken (Gallus gallus), as well as two important agricultural mammalian species: pig (Sus scrofa) and cattle (Bos taurus), with chicken and pig in particular being important to human biology and medicine. This report is the first to employ all core assays as defined by the Functional Annotation of Animal Genomes (FAANG) consortium, including information from a wide range of epigenomic assays for the same eight diverse tissues of three livestock species. Comparative analysis of these datasets and those from the human and mouse ENCODE projects revealed that although less than half of enhancers are positionally conserved between species, a core set of regulatory elements are functionally conserved independent of evolutionary distance. Further analysis suggested that tissue-specific transcription factor occupancy at regulatory elements and their predicted target genes were also conserved. Interestingly, the smaller chicken genome – relative to mammals – contains a reduced number of enhancers; however, each chicken enhancer targets more genes, on average, compared to their mammalian counterparts suggesting higher versatility. These datasets and corresponding analysis represent a unique opportunity for the emerging field of comparative epigenomics, as well as animal and human biology and medical research involving species that are globally important food resources.
Project description:Gene regulatory elements are central drivers of phenotypic variation and thus of critical importance towards understanding the genetics of complex traits. Here we present a genome-wide annotation of regulatory elements in a non-mammalian vertebrate, chicken (Gallus gallus), as well as two important agricultural mammalian species: pig (Sus scrofa) and cattle (Bos taurus), with chicken and pig in particular being important to human biology and medicine. This report is the first to employ all core assays as defined by the Functional Annotation of Animal Genomes (FAANG) consortium, including information from a wide range of epigenomic assays for the same eight diverse tissues of three livestock species. Comparative analysis of these datasets and those from the human and mouse ENCODE projects revealed that although less than half of enhancers are positionally conserved between species, a core set of regulatory elements are functionally conserved independent of evolutionary distance. Further analysis suggested that tissue-specific transcription factor occupancy at regulatory elements and their predicted target genes were also conserved. Interestingly, the smaller chicken genome – relative to mammals – contains a reduced number of enhancers; however, each chicken enhancer targets more genes, on average, compared to their mammalian counterparts suggesting higher versatility. These datasets and corresponding analysis represent a unique opportunity for the emerging field of comparative epigenomics, as well as animal and human biology and medical research involving species that are globally important food resources.
Project description:Gene regulatory elements are central drivers of phenotypic variation and thus of critical importance towards understanding the genetics of complex traits. Here we present a genome-wide annotation of regulatory elements in a non-mammalian vertebrate, chicken (Gallus gallus), as well as two important agricultural mammalian species: pig (Sus scrofa) and cattle (Bos taurus), with chicken and pig in particular being important to human biology and medicine. This report is the first to employ all core assays as defined by the Functional Annotation of Animal Genomes (FAANG) consortium, including information from a wide range of epigenomic assays for the same eight diverse tissues of three livestock species. Comparative analysis of these datasets and those from the human and mouse ENCODE projects revealed that although less than half of enhancers are positionally conserved between species, a core set of regulatory elements are functionally conserved independent of evolutionary distance. Further analysis suggested that tissue-specific transcription factor occupancy at regulatory elements and their predicted target genes were also conserved. Interestingly, the smaller chicken genome – relative to mammals – contains a reduced number of enhancers; however, each chicken enhancer targets more genes, on average, compared to their mammalian counterparts suggesting higher versatility. These datasets and corresponding analysis represent a unique opportunity for the emerging field of comparative epigenomics, as well as animal and human biology and medical research involving species that are globally important food resources.
Project description:Gene regulatory elements are central drivers of phenotypic variation and thus of critical importance towards understanding the genetics of complex traits. Here we present a genome-wide annotation of regulatory elements in a non-mammalian vertebrate, chicken (Gallus gallus), as well as two important agricultural mammalian species: pig (Sus scrofa) and cattle (Bos taurus), with chicken and pig in particular being important to human biology and medicine. This report is the first to employ all core assays as defined by the Functional Annotation of Animal Genomes (FAANG) consortium, including information from a wide range of epigenomic assays for the same eight diverse tissues of three livestock species. Comparative analysis of these datasets and those from the human and mouse ENCODE projects revealed that although less than half of enhancers are positionally conserved between species, a core set of regulatory elements are functionally conserved independent of evolutionary distance. Further analysis suggested that tissue-specific transcription factor occupancy at regulatory elements and their predicted target genes were also conserved. Interestingly, the smaller chicken genome – relative to mammals – contains a reduced number of enhancers; however, each chicken enhancer targets more genes, on average, compared to their mammalian counterparts suggesting higher versatility. These datasets and corresponding analysis represent a unique opportunity for the emerging field of comparative epigenomics, as well as animal and human biology and medical research involving species that are globally important food resources.
Project description:Gene regulatory elements are central drivers of phenotypic variation and thus of critical importance towards understanding the genetics of complex traits. Here we present a genome-wide annotation of regulatory elements in a non-mammalian vertebrate, chicken (Gallus gallus), as well as two important agricultural mammalian species: pig (Sus scrofa) and cattle (Bos taurus), with chicken and pig in particular being important to human biology and medicine. This report is the first to employ all core assays as defined by the Functional Annotation of Animal Genomes (FAANG) consortium, including information from a wide range of epigenomic assays for the same eight diverse tissues of three livestock species. Comparative analysis of these datasets and those from the human and mouse ENCODE projects revealed that although less than half of enhancers are positionally conserved between species, a core set of regulatory elements are functionally conserved independent of evolutionary distance. Further analysis suggested that tissue-specific transcription factor occupancy at regulatory elements and their predicted target genes were also conserved. Interestingly, the smaller chicken genome – relative to mammals – contains a reduced number of enhancers; however, each chicken enhancer targets more genes, on average, compared to their mammalian counterparts suggesting higher versatility. These datasets and corresponding analysis represent a unique opportunity for the emerging field of comparative epigenomics, as well as animal and human biology and medical research involving species that are globally important food resources.