Genetic diversity of Nigerian Indigenous Sheep breeds at the β-Lactoglobulin gene locus

The study assessed genetic diversity of four Nigerian sheep populations namely; Balami, Yankasa, Ouda and West African Dwarf (WAD) making use of blood sample. Extracted DNAs were used to study polymorphism at the β-lactoglobulin gene locus using RLFP-PCR process. Results revealed the percentage polymorphic locus was 100% while Shannon’s information index, observed homozygosity, expected heterozygosity, unbiased expected heterozygosity and fixation index were 0.656, 0.516, 0.464, 0.477 and -0.075, respectively. The gene flow (Nm) for all the population was estimated to be 7.65. The pairwise Fst was low and within the range of 0.0004(between Balami and WAD) to 0.0520 (between Balami and Yankasa). Variation within and between the populations of sheep shows that a large proportion of the observed variance (98% at p < 0.01) occurred within the breeds while only 2 % of the variance (p < 0.01) was contributed due to differences among the breeds. The nearest genetic distance was between the Balami and WAD (0.001) and between Ouda and the WAD (0.001). Phylogenetic analysis revealed three clusters. The present study showed that effort should be made to prevent the wearing away of the genetic make-up of the sheep populations considering the negative fixation index.