Zoological Studies

Phylogeographic Structure of the Formosan Wood Mouse, Apodemus semotus Thomas

Fu-Hsiung Hsu, Fei-Jann Lin and Yao-Sung Lin (2001) Phylogeographic structure of the Formosan wood mouse, Apodemus semotus Thomas (Muridae), was studied by the PCR-RFLP method. In total, 271 individuals collected from 23 locations throughout its distribution range in Taiwan were examined. Eleven restriction enzymes were used to assay restriction fragment length polymorphism in a 2800-bp PCR- amplified fragment of mtDNA, representing part of the cytochrome b (CYTb) and the control region (DL). In total, forty-four mtDNA haplotypes were detected. The sequence divergence between all pairs of haplotypes ranged between 0.20% and 3.20%. Phylogenetic analysis revealed that the 4 primary mtDNA lineages have been separated by sequence divergences of 0.86% to 1.78%. The geographic structure of mtDNA diversity and the lineage distribution are complex, but each lineage reveals a limited geographic distribution from north to south in the Central Mountain Range of Taiwan. According to the geographic distribution of 7 dominant haplotypes and the locality-based UPGMA dendrogram, we resolved the northern and south-central geographical assemblages. This phylogeographic pattern of the species might have resulted from a plausible historical scenario involving isolation of its populations in several intermontane refugia, and their re-dispersion and introgression in postgla- cial periods during the Pleistocene.