Species and genetic diversity of Bandicota (Murinae, Rodentia) from Myanmar based on mitochondrial and nuclear gene sequences

Bandicoot rats (genus Bandicota), widely known as rodent pests, are abundant and widespread throughout the continental part of the Indo-Malayan realm. However, their evolutionary history is not yet well understood. The molecular phylogenetic relationships of the three bandicoot rat species, Bandicota bengalensis, Bandicota indica, and Bandicota savilei, were assessed based on the gene sequences of the specimens collected from Myanmar, where all three species occur along with database sequences. Early divergence of B. savilei (1.5-1.7 million years ago) was inferred from the mitochondrial cytochrome b (Cytb) gene and the nuclear interphotoreceptor retinoid-binding protein (Irbp), and melanocortin 1 receptor (Mc1r) gene sequences. The Cytb lineage of B. bengalensis from Sri Lanka was distinct from the monophyletic lineage of the continental lineages of B. bengalensis and B. indica. This can be explained by the preservation of ancient mitochondrial DNA (mtDNA) in the insular population owing to female philopatry and male dispersal, given that no substantial intraspecies geographic subdivision was observed in the nuclear markers. The paraphyletic relationship of B. bengalensis with B. indicamay be explained by introgression of the mtDNA from B. bengalensis to B. indica, but further investigation is required to confirm this. B. bengalensis Cytb sequences from a wide area of Myanmar had limited nucleotide diversity (π = 0.00079), implying that the genetic diversity of B. bengalensisin Myanmar was acquired through Holocene human activities