Population structure of Santa Inês sheep: the impact of genomic information

Information on genetic diversity and population structure among sheep breeds is essential for genetic improvement, understanding environmental adaptation, as well as the utilization and conservation of sheep breeds. This research aims to analyze the genomic population structure of Santa Inês sheep managed on different properties in northeastern Brazil. A total of 390 individuals were genotyped for 52,744 SNPs. The six flocks evaluated showed population differentiation indices (pairwise Fst) ranging from 0.0342 to 0.0938. Estimates of gene flow showed high values, ranging from 0.89 to 1 (Nm) between flocks 2 and 3, which are from the same town. The average value for inbreeding (Fis) and the overall genetic differentiation index (Fst) were -0.05 and 0.06 respectively, observed in the F statistic for each of the loci analyzed in the six flocks. These results indicate that diversity is concentrated within populations. After the simulations using the Bayesian clustering method, the most probable number of genetic groups (K) detected was 5, where flock 4 and 6 form a single group. It can be concluded that the samples from the six flocks form five genetic populations with a level of diversity that has been conserved. The results of this study can contribute with important genetic information and can adequately help diversity within the breed, which provides a good opportunity for the sustainable use and maintenance of improvements in genetic resources in Santa Inês sheep populations in Brazil.