A Phylogenetic Foundation for Comparative Mammalian Genomics

摘要: A major effort is being undertaken to sequence an array of mammalian genomes. Coincidentally, the evolutionary relationships 18 presently recognized orders placental mammals are only just resolved. In this work we construct and analyse largest alignments amino acid data date. Our findings allow us set up a series superordinal groups (clades) act as prior hypotheses for further testing. Important include strong evidence clade Euarchonta+Glires (=Supraprimates) comprised primates, flying lemurs, tree shrews, lagomorphs rodents. addition, there good all except Xenarthra Afrotheria (=Boreotheria) previously recognised clades Laurasiatheria, Scrotifera, Fereuungulata, Ferae, Afrotheria, Euarchonta, Glires, Eulipotyphla. Accordingly, revised classification put forward. Using molecular divergence-time methods, ages splits estimated. While results strongly consistent with earliest divergences > 65 mybp (Cretaceous period), they suffer from greater uncertainty than appreciated. The early primate split tarsiers anthropoid lineage at ∼55 seen be especially informative fossil calibration point. statistical framework testing using SINE presented reveals significant support tarsier/anthropoid clade, well Cetruminantia Whippomorpha. Results also underline our thesis that while analysis can help hypothesised clades, SINEs obtainable sequencing 1-2 MB regions genomes essential them. contrast, derivations suggest empirical Bayesian methods may not robust estimators clades. findings, including study genes such TP53, make case shrew closer relative primates rodents, showing slower rate evolution in key cell cycle genes. Tree shrews consequently high value experimental animals candidate genome initiative.