Population Dynamics and Genetic Diversity in Bharat Merino Sheep

A study was conducted to assess the population structure, genetic variability and inbreeding in Bharat Merino sheep flocks. The pedigree records of Bharat Merino sheep maintained at ICAR-Central Sheep and Wool Research Institute, Avikanagar, Rajasthan (n=5158) and Southern Regional Research Centre, Mannavanur, Tamil Nadu (n=4974), from 1975 to 2021 were used for the study. Population and genetic variability traits were estimated based on the gene origin probabilities. The average equivalent generation (population’s pedigree depth) was 5.69. The estimated Wright’s F-statistic values were F_IS = -0.0012, F_IT = 0.0013 and F_ST = 0.0025. The effective population size and mean generation interval were 114.21 and 3.61 years, respectively. Inbreeding and average relatedness were 2.39 and 4.51%, respectively. The f_e/f_a ratio (degree of population bottlenecks) was 1.29. Sixteen key ancestors contributed 50% of the population’s genetic variability. Allele fixation through homozygosis did not occur in the population. The population possessed an appropriate amount of genetic variability, as evidenced by larger genetic differences within the flocks and the effective population size. A certain amount of genetic variability was lost due to the overuse of a few progenitors. The rate of inbreeding was under control, suggesting effective mating strategies to avoid inbreeding in Bharat Merino flocks.