Analysis of the role of retrotransposition in gene evolution in vertebrates

摘要: The dynamics of gene evolution are influenced by several genomic processes. One such process is retrotransposition, where an mRNA transcript reverse-transcribed and reintegrated into the DNA. We have surveyed eight vertebrate genomes (human, chimp, dog, cow, rat, mouse, chicken puffer-fish T. nigriviridis), for putatively retrotransposed copies genes. To gain a complete picture role robust strategy to identify putative retrogenes (PRs) was derived, in tandem with adaptation previous procedures annotate processed pseudogenes, also called retropseudogenes (RψGs). Mammalian estimated contain 400–800 PRs (corresponding ~3% genes), fewer RψGs non-mammalian vertebrates. Focussing on human we aged PRs, analysed evidence transcription selection pressures, assigned functional categories. significantly less mappable them, likely arise from alternatively-spliced genes, statistically overrepresented ribosomal-protein when compared proteome general. find spurts retrotransposition since lineage either species split dog lineage, >200 formed mouse its divergence rat. examine selection, calculated: (i) Ka/Ks values (ratios non-synonymous synonymous substitutions codons), (ii) significance conservation reading frames PRs. found >50 both that under pressure maintain integrity their coding sequences. For different subsets at stages mammalian evolution, some non-neutral despite expression these These results indicate retrotranspositions significant source novel sequences evolution.