Karyotypes of field mice of the genus (Mammalia: Rodentia) from China.

Karyotypes of four Chinese species of field mice of the genus Apodemus were examined, including (diploid chromosome number, 2=48, fundamental number of autosomal arms, FNa=56), (2=48, FNa=48), (2=48, FNa=48), and (2=48, FNa=48). Karyotypes of , , and are reported here for the first time, providing useful information for their species taxonomy. Determining the karyotypes of all species of Apodemus in Asia, both in this and previous studies, provides a solid overview of the chromosome evolution and species differentiation of the genus in East Asia. In addition to allopatric speciation, chromosome rearrangements likely played an important role in the formation of the four species groups as well as speciation within each group in East Asia. For example, increased centromeric heterochromatin in may have contributed to the post-mating reproductive isolation from the -- semotus clade.