Project description:Evolutionary studies are often limited by missing data that are critical to understanding the history of selection. Selection experiments, which reproduce rapid evolution under controlled conditions, are excellent tools to study how genomes evolve under selection. Here we present a genomic dissection of the Longshanks selection experiment, in which mice were selectively bred over 20 generations for longer tibiae relative to body mass, resulting in 13% longer tibiae in two replicates. We synthesized evolutionary theory, genome sequences and molecular genetics to understand the selection response and found that it involved both polygenic adaptation and discrete loci of major effect, with the strongest loci likely to be selected in parallel between replicates. We show that selection may favor de-repression of bone growth through inactivating two limb enhancers of an inhibitor, Nkx3-2. Our integrative genomic analyses thus show that it is possible to connect individual base-pair changes to the overall selection response.
Project description:Evolutionary studies are often limited by missing data that are critical to understanding the history of selection. Selection experiments, which reproduce rapid evolution under controlled conditions, are excellent tools to study how genomes evolve under selection. Here we present a genomic dissection of the Longshanks selection experiment, in which mice were selectively bred over 20 generations for longer tibiae relative to body mass, resulting in 13% longer tibiae in two replicates. We synthesized evolutionary theory, genome sequences and molecular genetics to understand the selection response and found that it involved both polygenic adaptation and discrete loci of major effect, with the strongest loci likely to be selected in parallel between replicates. We show that selection may favor de-repression of bone growth through inactivating two limb enhancers of an inhibitor, Nkx3-2. Our integrative genomic analyses thus show that it is possible to connect individual base-pair changes to the overall selection response.
2019-07-09 | GSE121564 | GEO
Project description:Genomic characterization of world's longest selection experiment in mouse reveals the complexity of polygenic traits.
Project description:Understanding how polygenic traits evolve and respond to selection is a major unsolved problem, because challenges exist for identifying genes underlying a complex trait and understanding how multi-locus selection operates in the genome. Here we used artificial selection experiments to study polygenic response to selection. Inbred strains from seven independent long-term selection experiments in mice for extreme bodyweight (“High” lines weigh 77-42g vs. 40-16g in “Controls” lines), were genotyped at 527,572 SNPs to identify genetic variants controlling bodyweight. We identified 67 high-resolution parallel selected regions (PSRs) where multiple High lines share variants rarely found among the Controls. By comparing allele frequencies in one selection experiment against its unselected control, we found classical selective sweep signatures centered on the PSRs. Multiple lines of evidence support two G protein-coupled receptors GPR133 and Prlhr, as positional candidate genes controlling bodyweight. Artificial selection may mimic natural selection in the wild: compared to control loci, we detected reduced heterozygosity in PSRs in wild populations of unusually large mice on islands. Many PSRs overlap loci associated with human height variation, possibly through evolutionary conservation of functional pathways. Our data suggest that parallel selection on complex traits may evoke parallel responses at many genes involved in diverse but relevant pathways. These samples were used to test the enrichment of certain gene functional categories. Genomic DNA SNP comparison between artificially selected high lines (BEH, DAHi, DUH, MUH, EDH, RAHi, Du6/G154 and Du6i/G80) and unselected control lines.
Project description:Understanding how polygenic traits evolve and respond to selection is a major unsolved problem, because challenges exist for identifying genes underlying a complex trait and understanding how multi-locus selection operates in the genome. Here we used artificial selection experiments to study polygenic response to selection. Inbred strains from seven independent long-term selection experiments in mice for extreme bodyweight (“High” lines weigh 77-42g vs. 40-16g in “Controls” lines), were genotyped at 527,572 SNPs to identify genetic variants controlling bodyweight. We identified 67 high-resolution parallel selected regions (PSRs) where multiple High lines share variants rarely found among the Controls. By comparing allele frequencies in one selection experiment against its unselected control, we found classical selective sweep signatures centered on the PSRs. Multiple lines of evidence support two G protein-coupled receptors GPR133 and Prlhr, as positional candidate genes controlling bodyweight. Artificial selection may mimic natural selection in the wild: compared to control loci, we detected reduced heterozygosity in PSRs in wild populations of unusually large mice on islands. Many PSRs overlap loci associated with human height variation, possibly through evolutionary conservation of functional pathways. Our data suggest that parallel selection on complex traits may evoke parallel responses at many genes involved in diverse but relevant pathways. These samples were used to test the enrichment of certain gene functional categories.
Project description:Understanding how polygenic traits evolve and respond to selection is a major unsolved problem, because challenges exist for identifying genes underlying a complex trait and understanding how multi-locus selection operates in the genome. Here we used artificial selection experiments to study polygenic response to selection. Inbred strains from seven independent long-term selection experiments in mice for extreme bodyweight (“High” lines weigh 77-42g vs. 40-16g in “Controls” lines), were genotyped at 527,572 SNPs to identify genetic variants controlling bodyweight. We identified 67 high-resolution parallel selected regions (PSRs) where multiple High lines share variants rarely found among the Controls. By comparing allele frequencies in one selection experiment against its unselected control, we found classical selective sweep signatures centered on the PSRs. Multiple lines of evidence support two G protein-coupled receptors GPR133 and Prlhr, as positional candidate genes controlling bodyweight. Artificial selection may mimic natural selection in the wild: compared to control loci, we detected reduced heterozygosity in PSRs in wild populations of unusually large mice on islands. Many PSRs overlap loci associated with human height variation, possibly through evolutionary conservation of functional pathways. Our data suggest that parallel selection on complex traits may evoke parallel responses at many genes involved in diverse but relevant pathways. These samples were used to test the enrichment of certain gene functional categories.
Project description:We report that TAF1 phosphorylates p53 at Thr55 on the p21 promoter and this phosphorylation leads to dissociation of p53 from the promoter. Indeed, ChIP-Seq analysis reveals p53 undergoes promoter dissociation at a global level after response to DNA damage, underscoring general nature of the regulation. UVC treatment at the time points indicated was used to access p53 transcription factor signal induction and termination.
Project description:To investigate genomic plasticity over time associated with response to standard chemotherapy, we collected longitudinal liver metastasis (LM) samples from 155 patients and characterized the copy number aberration (CNA) landscape and its effect on the transcriptome. CNA profiles of lesions exhibiting different treatment response were compared and focal genomic divergences reported. By investigating genomic-phenotype associations of the largest reported LM cohort to date, we identified novel molecular features associated with drug response supporting the relevance of collecting clinical metastatic samples.
Project description:Longitudinal transcriptomic profiling of myeloid cells from cerebral hemorrhage patients reveals conserved features of the inflammatory response and highlights the potential importance of cellular metabolism in guiding macrophage functions and improved patient outcomes.