Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Molecular evolution of genes in avian genomes. | Nam et al. Genome Biology 2010 11 R68 http 2010 11 6 R68 w Genome Biology RESEARCH Open Access Molecular evolution of genes in avian genomes Kiwoong Nam 1 Carina Mugal1 Benoit Nabholz1 Holger Schielzeth1 Jochen BW Wolf1 Niclas Backstrom1 Axel Kunstner1 Christopher N Balakrishnan2 Andreas Heger3 Chris P Ponting3 David F Clayton2 and Hans Ellegren 1 Abstract Background Obtaining a draft genome sequence of the zebra finch Taeniopygiaguttata the second bird genome to be sequenced provides the necessary resource for whole-genome comparative analysis of gene sequence evolution in a non-mammalian vertebrate lineage. To analyze basic molecular evolutionary processes during avian evolution and to contrast these with the situation in mammals we aligned the protein-coding sequences of 8 384 1 1 orthologs of chicken zebra finch a lizard and three mammalian species. Results We found clear differences in the substitution rate at fourfold degenerate sites being lowest in the ancestral bird lineage intermediate in the chicken lineage and highest in the zebra finch lineage possibly reflecting differences in generation time. We identified positively selected and or rapidly evolving genes in avian lineages and found an overrepresentation of several functional classes including anion transporter activity calcium ion binding cell adhesion and microtubule cytoskeleton. Conclusions Focusing specifically on genes of neurological interest and genes differentially expressed in the unique vocal control nuclei of the songbird brain we find a number of positively selected genes including synaptic receptors. We found no evidence that selection for beneficial alleles is more efficient in regions of high recombination in fact there was a weak yet significant negative correlation between w and recombination rate which is in the direction predicted by the Hill-Robertson effect if slightly deleterious mutations contribute to protein evolution. These findings set the stage for .
