Fast genes and slow clades: comparative rates of molecular evolution in mammals.

摘要: Although interest in the rate of molecular evolution and clock remains high, our knowledge for most groups these areas is derived largely from a patchwork studies limited both their taxon coverage number genes examined. Using comprehensive data set 44 (18 nDNA, 11 tRNA 15 additional mtDNA genes) together with virtually complete dated phylogeny extant mammals, I 1) describe differences (i.e. substitution rate) within this group an explicit phylogenetic quantitative framework 2) present first attempt to localize positions any shifts. Significant were few confirmed several long-held trends, including progressive slowdown hominids reduced Cetacea. However, many new patterns also uncovered, mammalian orders being characterized generally by basal slowdowns. A link between size clade (which derives its net speciation suggested, species-poor major clades ("orders") showing more decreased rates that often extend throughout entire clade. increases rare, (murid) rodents fast, but not significantly so respect other mammals as whole. Despite clear lineage-specific differences, change gradually along lineages, supporting potential existence local mammals. Together, results will lay foundation broad-scale analysis establish correlates causes