The analysis of genetic diversity and differentiation of six Chinese cattle populations using microsatellite markers

A total of 321 individuals from six cattle populations of four species in a bovine subfamily in China were studied using 12 pairs of microsatellite markers. The genetic diversities within and between populations were calculated. The phylogenetic trees were constructed by(δμ)2 and DA distances, and the divergence times between populations were estimated by (δμ)2. Altogether, 144 microsatellite alleles were detected including 24 private alleles and nine shared alleles. Chinese Holstein had the largest number of private alleles (10), whereas,Bohai black and Buffalo had the smallest number of private alleles (2). Chinese Holstein showed the highest genetic variability. Its observed number of alleles (Na), mean effective number of alleles (MNA), and mean heterozygosity (He) were 7.7500, 4.9722, and 0.7719,respectively, whereas, the Buffalo and Yak showed low genetic variability. In the phylogenetic trees, Luxi and Holstein grouped first,followed by Bohai and Minnan. Yak branched next and buffalo emerged as the most divergent population from other cattle populations.Luxi and Bohai were estimated to have diverged 0.039-0.105 million years ago (MYA), however, buffalo and Holstein diverged 0.501-1.337 MYA. The divergence time of Yak versus Minnan, Holstein and buffalo was 0.136-0.363, 0.273-0.729, and 0.326-0.600MYA, respectively.