Project description:East African cichlid fishes have diversified in an explosive fashion, but the (epi)genetic basis of the phenotypic diversity of these fishes remains largely unknown. Although transposable elements (TEs) have been associated with phenotypic variation in cichlids, little is known about their transcriptional activity and epigenetic silencing. Here, we describe dynamic patterns of TE expression in African cichlid gonads and during early development. Orthology inference revealed an expansion of piwil1 genes in Lake Malawi cichlids, likely driven by PiggyBac TEs. The expanded piwil1 copies have signatures of positive selection and retain amino acid residues essential for catalytic activity. Furthermore, the gonads of African cichlids express a Piwi-interacting RNA (piRNA) pathway that target TEs. We define the genomic sites of piRNA production in African cichlids and find divergence in closely related species, in line with fast evolution of piRNA-producing loci. Our findings suggest dynamic co-evolution of TEs and host silencing pathways in the African cichlid radiations. We propose that this co-evolution has contributed to cichlid genomic diversity.
Project description:Gene expression profiling of pooled late stage embryos from Leucoraja erinacea, Scyliorhinus canicula and Callorhinchus milii show that HOXC cluster genes are not expressed in the two elasmobranch fishes, L. erinacea and S. canicula. This finding supports the observations that these genes are not found in whole genome shotgun sequencing of L. erinacea or genomic clones from S. canicula. Profile gene expression in pooled late stage embryos from three species (L. erinacea, S. canicula and C. milii)
Project description:East African cichlid fishes have diversified in an explosive fashion, but the (epi)genetic basis of the phenotypic diversity of these fishes remains largely unknown. Although transposable elements (TEs) have been associated with phenotypic variation in cichlids, little is known about their transcriptional activity and epigenetic silencing. Here, we describe dynamic patterns of TE expression in African cichlid gonads and during early development. Orthology inference revealed an expansion of piwil1 genes in Lake Malawi cichlids, likely driven by PiggyBac TEs. The expanded piwil1 copies have signatures of positive selection and retain amino acid residues essential for catalytic activity. Furthermore, the gonads of African cichlids express a Piwi-interacting RNA (piRNA) pathway that target TEs. We define the genomic sites of piRNA production in African cichlids and find divergence in closely related species, in line with fast evolution of piRNA-producing loci. Our findings suggest dynamic co-evolution of TEs and host silencing pathways in the African cichlid radiations. We propose that this co-evolution has contributed to cichlid genomic diversity.
Project description:Gene expression profiling of pooled late stage embryos from Leucoraja erinacea, Scyliorhinus canicula and Callorhinchus milii show that HOXC cluster genes are not expressed in the two elasmobranch fishes, L. erinacea and S. canicula. This finding supports the observations that these genes are not found in whole genome shotgun sequencing of L. erinacea or genomic clones from S. canicula.
2011-12-15 | GSE26235 | GEO
Project description:Pig microbial and immune traits respond to host evolutionary history and ecology across multiple scales (16S)