Assessment of Genetic Variability and Structuring of Riverine Buffalo Population (Bubalus bubalis) of Indo-Gangetic Basin

Abstract

The buffalo population of Uttar Pradesh (UP) constitutes 26.1% of the total buffalo population of India, yet this population has not been classified into distinct breeds or subpopulations due to lack of systematic study. Genetic variation at 30 microsatellite loci was examined and statistical analysis was carried out to reveal genetic diversity, demographic parameters of these buffaloes and to investigate the existence of population substructures underlying geographical distribution. The mean number of alleles per locus was 13.26 and mean effective number of alleles was 3.74, whereas mean observed and expected heterozygosities were found to be 0.57 and 0.67 in UP buffaloes. Principal component analysis (PCA) based on allele frequency data revealed subclustering of UP buffalo population. Bayesian analysis result also revealed clear membership of individuals into five clusters indicating a genetic subdivision within the UP buffalo population. The buffaloes of Western and Central regions of UP were subtly separated while buffaloes of Tarai area and Bhadawari buffaloes revealed distinctive population structure. The buffaloes of Mau, Ballia and Ghazipur districts of Eastern region also had a distinctive genetic structure. The analysis of data on buffaloes of Indo-Gangetic plains revealed that population was in mutation drift equilibrium. The observed mean M ratio in the population was above the critical significance value (Mc) suggesting that it has not suffered any severe reduction in effective population size. The statistical tests revealed a historical constancy of size of buffalo in this geographical area. The high level of genetic variability indicates UP buffalo population is a vast reservoir of genetic diversity and this shall help in taking informed conservation decisions and sustainable utilization.