Microsatellite analysis in two populations of Kunming mice.

Kunming mice are the most widely used outbred colony in China. Differences in biological characters and drug reactions among different populations have been observed when using Kunming mice. But the molecular genetic profiles of Kunming mice and the extent of genetic differentiation among populations are unclear. Fifteen microsatellite markers were screened by a fluorescence-based semi-automated genotyping method for the two main populations of Kunming mice from Beijing (BJ) and Shanghai (SH) in China. The observed number of alleles, effective number of alleles, observed heterozygosity, unbiased expected heterozygosity and Shannon information index were used to estimate the genetic variation within the populations. A total of 89 alleles were detected in the two populations, with two to 12 at each locus, and the mean unbiased expected heterozygosity was 0.5724, which implies that there is abundant genetic variation in the populations of Kunming mice. Population differentiation was shown by shared alleles, F-statistics, Nei genetic distance and Nei genetic identity. In population BJ and population SH, respectively, only 35 of 61 and 35 of 63 alleles were shared by both. The Fst per locus varied from 0.0131 (D2Mit30) to 0.5697 (D7Mit281) and the average Fst of all loci was 0.1433, which indicates moderate genetic differentiation between the two Kunming mouse populations. The differences were also observed by Nei's [Genetic distance between populations. Am Nat 1972;106:283-92](1) genetic distance (0.3987) and Nei's [Estimation of average heterozygosity and genetic distance from a small number of individuals. Genetics 1978;89:583-90](2) unbiased measures of genetic distance (0.3881) estimates of subdivision. This research on Kunming mouse genetic diversity will assist in developing a national plan for the unification and standardization of the populations of Kunming mice in China.