Application of bovine microsatellite markers for genetic diversity analysis of Swiss yak (Poephagus grunniens)

In order to assess the applicability of bovine microsatellite markers for population genetic studies in Swiss yak, 131 bovine microsatellite markers were tested on a panel of 10 animals. Efficient amplification was observed for 124 markers (94.6%) with a total of 476 alleles, of which 117 markers (94.3%) were polymorphic. The number of alleles per locus among the polymorphic markers ranged from two to nine. Seven loci (ILSTS005, BMS424B, BMS1825, BMS672, BM1314, ETH123 and BM6017) failed to amplify yak genomic DNA. Two cattle Y-chromosome specific microsatellite markers (INRA126 and BM861) amplified genomic DNA from both male and female yaks. However, two additional markers on cattle Y-chromosome (INRA124 and INRA189) amplified DNA from only males. Of the polymorphic markers, 24 microsatellites proposed by CaDBase for within- and cross-species comparisons and two additional highly polymorphic markers (MHCII and TGLA73) were used to investigate the genetic variability and the population structure of a Swiss yak herd that included 51 additional animals. The polymorphic information content ranged from 0.355 to 0.752, while observed heterozygosity (HO) ranged from 0.348 to 0.823. Furthermore, a set of 13 markers, organized into three multiplex polymerase chain reactions, was evaluated for routine parentage testing. This set provided an exclusion probability in a family of four yaks (both parents and two offspring) of 0.995. These microsatellites serve as useful tools for genetic characterization of the yak, which continues to be an important domestic livestock species.