Abstract: This study was to isolate microsatellite markers from Microtus fortis genome by magnetic beads enrichments. Through hybridization of biotin-labeled microsatellite oligonucleotide probes, which were captured by streptavidin-coated magnetic with the adaptor–ligated enzyme-digested genome fragments, single-stranded DNA fragments containing mi-crosatellites were obtained. After PCR amplification, these fragments were then cloned into T vectors and were transformed into competent cells subsequently. Ninety-two microsatellite sequences were randomly isolated from 70 positive clones. Twenty-one out of 27 pairs of designed microsatellite primers were screened out from the microsatellite sequences, and 10 out of the 21 microsatellite loci were used to investigate the genetic diversity of three populations of M. fortis, Hunan (wild), Hunan (domesticated), and Ningxia (domesticated). All the 10 microsatellite loci used to analyze the genetic diversity exhibited a good level of polymorphism. The values of observed number of alleles (Na), effective number of alleles (Ne), observed heterozygosity (Ho), expected heterozygosity (He) and polymorphic information content (PIC) were all the highest in the Hunan (wild) population, lower in the Hunan (domesticated) population, and the lowest in the Ningxia (domesticated) population.

Key words: Microtus fortis, enrichment by magnetic beads, microsatellite, genetic diversity