Genetic diversity, population structure and gene flow among indigenous Nigerian sheep breeds

Genetic diversity, population structure and gene flow among indigenous Nigerian sheep breeds were investigated to enhance understanding of their genetic differentiation and adaptability. A total of 150 sheep, comprising Balami, Uda and Yankasa breeds (50 individuals per breed), were selected for phenotypic characterisation. Morphological traits such as head length, body length, and heart girth were assessed. Blood samples from 45 sheep (15 per breed) were collected for DNA extraction, polymerase chain reaction (PCR) and sequencing. The obtained sequences were subjected to bioinformatics analysis to evaluate genetic diversity, population structure and gene flow. The results demonstrated significant genetic variation among the breeds. The association of the leptin gene SNP 3 with phenotypic traits revealed that the TT genotype in Balami and Uda was linked to larger body dimensions, whereas the AA genotype in Yankasa was associated with smaller body size. Genetic differentiation indices (Gst, Fst and Dxy) indicated moderate genetic divergence among the breeds, with Balami and Yankasa showing higher differentiation (Fst = 0.25000) compared to Uda and Yankasa (Fst = 0.07143). Gene flow analysis suggested moderate genetic exchange among the breeds, with Balami exhibiting higher heterozygosity (Hs = 0.5) than Yankasa (Hs = 0.4). Tajima’s D values were positive for all the breeds, indicating potential balancing selection or population contraction. These findings highlight the importance of genetic characterisation in livestock improvement programmes. The observed genetic diversity and gene flow patterns provide insights into breed conservation strategies and selective breeding programmes to enhance productivity and adaptability.