title: Dating of divergences within the Rattus genus phylogeny using whole mitochondrial genomes.
abstract: The timing and order of divergences within the genus Rattus have, to date, been quite speculative. In order to address these important issues we sequenced six new whole mitochondrial genomes from wild-caught specimens from four species, Rattus exulans, Rattus praetor, Rattus rattus and Rattus tanezumi. The only rat whole mitochondrial genomes available previously were all from Rattus norvegicus specimens. Our phylogenetic and dating analyses place the deepest divergence within Rattus at approximately 3.5 million years ago (Mya). This divergence separates the New Guinean endemic R. praetor lineage from the Asian lineages. Within the Asian/Island Southeast Asian clade R. norvegicus diverged earliest at approximately 2.9Mya. R. exulans and the ancestor of the sister species R. rattus and R. tanezumi subsequently diverged at approximately 2.2Mya, with R. rattus and R. tanezumi separating as recently as approximately 0.4Mya. Our results give both a better resolved species divergence order and diversification dates within Rattus than previous studies.
authors: Department of Anthropology and Allan Wilson Centre for Molecular Ecology and Evolution, The University of Auckland, Auckland, New Zealand. j.robins@auckland.ac.nz
authors: Judith H
authors: JH
authors: Robins
authors: Patricia A
authors: PA
authors: McLenachan
authors: Matthew J
authors: MJ
authors: Phillips
authors: Lauren
authors: L
authors: Craig
authors: Howard A
authors: HA
authors: Ross
authors: Elizabeth
authors: E
authors: Matisoo-Smith
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D004272:DNA, Mitochondrial / Q000235:genetics; D019143:Evolution, Molecular; D049810:Genetic Speciation; D054629:Genome, Mitochondrial; D016013:Likelihood Functions; D008928:Mitochondria / Q000235:genetics; D008957:Models, Genetic; D010802:Phylogeny; D051381:Rats / Q000145:classification* / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D004272:DNA, Mitochondrial