Project description:The complexity of the brain and the links entailed to its functional diversity remain a major challenge of biology to understand. Distinct anatomical areas regulate a vast array of processes including organismal homeostasis, cognitive functions and susceptibility to neurological pathologies, many of which define our species. Distal enhancers have emerged as key regulatory elements that acquire epigenetic modifications in a cell-type specific manner, thus enforcing cell- and species-specific gene expression programs. Here, we survey the epigenetic landscape of promoters and cis-regulatory elements in 87 anatomically distinct regions of the human brain, spanning over a hundred different anatomical structures. ChIP-Seq of various regions of the human brain. Also includes mouse and rat samples. Contributor: The Netherlands Brain Bank
Project description:MicroRNAs (miRNAs) are a class of small, endogenous RNAs that regulate mRNA expressions post-transcriptionally. To study their expression, we collected and sequenced small RNA libraries in Drosophila species. To survey their regulation divergence, we dissected testes from miR-983 mutant and control flies in two sibling species and performed an RNA-seq analysis.
Project description:The complexity of the brain and the links entailed to its functional diversity remain a major challenge of biology to understand. Distinct anatomical areas regulate a vast array of processes including organismal homeostasis, cognitive functions and susceptibility to neurological pathologies, many of which define our species. Distal enhancers have emerged as key regulatory elements that acquire epigenetic modifications in a cell-type specific manner, thus enforcing cell- and species-specific gene expression programs. Here, we survey the epigenetic landscape of promoters and cis-regulatory elements in 87 anatomically distinct regions of the human brain, spanning over a hundred different anatomical structures.
Project description:Gene copy number variation (CNV) is a form of genetic polymorphism that contributes significantly to genome size and function but remains poorly characterized due to technological limitations. Inter-specific comparisons of CNVs in recently diverged plant species are crucial to uncover selection patterns underlying adaptation of a species to stressful environments. Especially given that gene amplifications have long been implicated in emergence of species-specific traits, we conducted a genome-wide survey to identify species-specific gene copy number expansions and deletions in the model extremophile species - Arabidopsis halleri that has diverged in evolutionarily recent time from Arabidopsis thaliana. Cross-species cDNA array based comparative genomic hybridization was employed to compare and identify gene copy number variation in the two sister-species - the metallophyte Arabidopsis halleri and non-metallophyte Arabidopsis lyrata, both relative to Arabidopsis thaliana. We uncovered an unprecedented level of gene copy number polymorphism in Arabidopsis halleri, with a species-specific enrichment of metal homeostasis function in the genes found to be copy number expanded, thus indicating CNV as a mechanism that underlies the key physiological trait of metal hyperaccumulation and hypetolerance in A. halleri.
2016-09-30 | GSE52003 | GEO
Project description:Survey of RNA viruses infecting termite species
Project description:Dnmt1 epigenetically propagates symmetrical CG methylation in many eukaryotes. Their genomes are typically depleted of CG dinucleotides because of imperfect repair of deaminated methylcytosines. Here, we extensively survey diverse species lacking Dnmt1 and show that, surprisingly, symmetrical CG methylation is nonetheless frequently present and catalyzed by a different DNA methyltransferase family, Dnmt5. Numerous Dnmt5-containing organisms that diverged more than a billion years ago exhibit clustered methylation, specifically in nucleosome linkers. Clustered methylation occurs at unprecedented densities and directly disfavors nucleosomes, contributing to nucleosome positioning between clusters. Dense methylation is enabled by a regime of genomic sequence evolution that enriches CG dinucleotides and drives the highest CG frequencies known. Species with linker methylation have small, transcriptionally active nuclei that approach the physical limits of chromatin compaction. These features constitute a previously unappreciated genome architecture, in which dense methylation influences nucleosome positions, likely facilitating nuclear processes under extreme spatial constraints. DNA methylation, RNA and nucleosome sequencing data for diverse eukaryotes
Project description:Regulatory changes have long been hypothesized to play an important role in primate evolution. To identify adaptive regulatory changes in humans, we performed a genome-wide survey for genes whose regulation evolves under natural selection. To do so, we used a novel multi-species microarray to measure gene expression levels in livers, kidneys, and hearts from six humans, chimpanzees, and rhesus macaques.