Re-evaluation of the phylogeny based on mitochondrial cytochrome b gene in the house shrew, Suncus murinus-S. montanus species complex, with special reference to Yemen and Myanmar populations

The house shrew (Suncus murinus-S. montanus species complex) is considered to have been unintentionally introduced by humans from their original range to other regions around the Indian Ocean and neighboring seas, but this has yet not fully been investigated. A phylogenetic tree and haplotype network were reconstructed based on the mitochondrial cytochrome b gene nucleotide sequences (1140 bp) of 179 individuals of house shrews from 46 localities in southern East Asia, Southeast Asia, West Asia, and islands in the western Indian Ocean. There was small genetic variation among shrews in Japan (Okinawa), southern China, Vietnam, and insular Southeast Asia. However, the shrew populations in Myanmar and Sri Lanka showed of a variety of different haplotypes. In the region of the western Indian Ocean, three interesting findings were obtained. First, the shrews on Zanzibar Island (Tanzania) shared same haplotype as those in southwestern Iran, and the haplotype was close to a group in Pakistan, despite these three regions being distantly located. Second, inferring from the haplotype network, it was suggests that the shrews in Yemen might have derived from Madagascar/Comoros populations. Third, the shrews on Réunion Island were genetically different from other populations around the western Indian Ocean but closer to Malaysia and Myanmar populations. Thus, the present study demonstrates that there have been dynamic immigration/emigration processes in the house shrews, especially for those around the western Indian Ocean. In addition, the house shrews in Myanmar may include several different species.