Genetic diversity of Indian native cattle breeds as analysed with 20 microsatellite loci

The aim of the present study was to assess the genetic variation and establish the relationship amongst the three Indian zebu cattle breeds using 20 bovine‐specific microsatellite markers. A total of 136 unrelated DNA samples from Sahiwal (SC), Hariana (HC) and Deoni (DC) breeds of cattle were genotyped to estimate within and between breed genetic diversity indices. The estimated mean allelic diversity was 5.2, 6.5 and 5.9 in SC, HC and DC, respectively, with a total of 167 alleles. The average observed and expected heterozygosity for the population varied from 0.42 (SC) to 0.59 (DC), and from 0.61 (SC) to 0.70 (DC), respectively. Low values of genetic variability estimates were observed in SC when compared with DC and HC, indicating some loss of variability because of its relatively small population size. From global F‐statistics a significant deficit of heterozygotes of 24.2% (p < 0.05) was observed for each one of the analysed breeds whereas the total population had a 32.8% (p < 0.05) deficit of heterozygotes. The F_ST estimates demonstrated that approximately 88.7% of the total genetic variation was because of the genetic differentiation within each breed. Pair‐wise breed differentiation, Nei's standard and D_A genetic distance estimates revealed relatively close genetic similarity between HC and DC in comparison with SC. In the UPGMA‐based phylogenetic tree constructed from the genetic distances, HC and DC were grouped together in one cluster and SC in the other. The estimated time of divergence suggested a separation time of approximately 776 years between DC and HC, and a comparatively longer period (1296 years) between DC and SC.