Genetic admixture and population structure analysis of Indian water buffaloes (Bubalus bubalis) using STR markers

India has a vast riverine and swamp buffalo diversity adapted to various agro-ecological conditions. In the present study, genetic diversity data for 10 different buffalo populations of India, using 20 highly polymorphic microsatellite markers has been generated for the genetic diversity analysis. The buffalo populations of Eastern Odisha state, were the primary focus.

The minimal spanning network based on Bruvo's distance, PCA (Principal Component Analysis) based on the Fst (Fixation Index) values, and genetic admixture analysis using both the STRUCTURE and 'snapclust' were performed. The analysis could identify the Manda population as distinct from other Odisha buffalo breeds as well as adjoining Chhattisgarhi buffalo breeds. The total observed number of alleles ranged between 143 (Manda) and 301 (Paralakhemundi) with an average of 204 alleles per breed. The Sambhalpuri buffalo population also clustered into two separate subpopulations, half of the unique sub-population located geographically south-wards, displayed no admixture with any of the adjacent buffalo populations. The Manda buffalo population has shown sufficient allelic richness and heterozygosity under random mating being practiced in the field conditions.

The study has led to the identification of the Manda as a distinct buffalo population, and the germplasm has been registered as a new Indian buffalo breed. Whereas, the Sambhalpuri population requires elaborate analysis to confirm the existence of two distinct sub-populations.