Microsatellite-based Genetic Diversity and Mutation-Drift Equilibrium in Dharwadi Buffalo (Bubalus bubalis) of India

Genetic diversity was assessed in a buffalo population (Dharwadi) of Karnataka by utilizing 25 heterologous bovine microsatellite markers. Genotypic status of individuals at each locus was identified by automated DNA sequencer, and allelic data were analyzed for genetic diversity parameters. Observed number of alleles varied between 5 and 19 with 13.12 ± 0.80 alleles per locus. High level of heterozygosity (0.63) indicated plenty of existing genetic diversity in this buffalo population. Within-population inbreeding estimate (FIS) was significantly positive (0.186) and 88% of the investigated loci contributed toward the homozygote excess. Accordingly, significant deviation from Hardy–Weinberg equilibrium was observed at 24 of 25 analyzed loci. The population did not suffer reduction in effective population size in the last few generations. Assessment of Dharwadi buffalo population for mutation-drift equilibrium did not reveal significant heterozygosity excess under all the models of microsatellite evolution as per Sign test. No shift was recorded in the frequency distribution of alleles, and a normal L-shaped curve indicated absence of any recent genetic bottleneck. The study highlighted sufficient genetic variability within Dharwadi buffalo population that can be utilized in combination with phenotype and production information for registration as a distinct breed of Indian buffalo.