[Construction and identification on enriched microsatellite library from yak genome].

We constructed the first microsatellite-enriched library of yak according to the strong affinity between biotin and streptavidin. The method included ligation of 300 approximately 1 000 bp enzyme-digested fragments and adaptors, affinity capture of microsatellite repeat using biotinylated oligoprobe ((CA)12, (CCG) 8, (CAG)8, (TTTC) 8) attached to streptavidin-coated magnetic beads, PCR amplification using the 21-mer adaptor oligonucleotide as primer to obtain double-stranded targeted fragments, religated into pMD18-T vector and transformed to DH5alpha. The results of sequencing showed that 37 of 48 readable sequences contained microsatellites indicating a high degree of microsatellite enrichment. The new polymorphic microsatellite markers we have identified and characterized will contribute to the yak genetic linkage mapping, molecular evolution and phylogenetic studies, marker assistant selection and QTLs location of yak main economic traits.