Late Quaternary environmental and human impacts on the mitochondrial DNA diversity of four commensal rodents in Myanmar

We addressed the spatiotemporal characteristics of four commensal rodent species occurring in Myanmar in comparison with other areas of the Indo-Malayan region. We examined sequence variations of the mitochondrial cytochrome bgene (Cytb) in the Pacific rat (Rattus exulans), roof rat(Rattus rattuscomplex, RrC), lesser bandicoot rat (Bandicota bengalensis), and house mouse(Mus musculus) using the recently developed time-dependent evolutionary rates of mtDNA. The Cytbsequences of RrC from Myanmar were shown to belong to RrC Lineage II, and their level of genetic diversity was relatively high compared to those of the other three species. RrC was found to have experienced bottleneck and rapid expansion events at least twice in the late Pleistocene period in Myanmar and a nearby region. Accordingly, paleoclimatic environmental fluctuations were shown to be an important factor affecting rodents in the subtropics of the Indo-Malayan region. Our results show that human activities during the last...