Polymorphism of selected candidate genes in Ghanaian sheep breeds

Abstract

Polymorphisms of candidate genes BMP15 and GDF9, GH and CAST that influence fecundity, growth, and carcass traits, respectively, were studied in two Ghanaian sheep breeds to determine whether these breeds were polymorphic or monomorphic at the above gene loci. DNA was extracted from blood samples collected from 63 Sahel and 49 Djallonké sheep and analyzed by polymerase chain reaction – restriction fragment length polymorphism (PCR-RFLP) technique. Restriction enzyme digestion of the BMP15-FecXB locus revealed two genotypes (AA and AB) in both populations with genotype AA recording the highest frequency in both populations. At the BMP15- FecXG locus, genotype Gg had the highest frequency (0.548) in the Djallonké population whereas GG frequency (0.719) was the highest in the Sahel population. Analysis of GDF9-FecGH with DdeI endonuclease also revealed two genotypes, AA and AB in both populations with the genotypic frequency of AA being the highest in both populations (Sahel= 0.933 and Djallonké= 0.98). At the GH gene locus, restriction digestion with HaeIII showed three genotypes (AA, AB, BB), with genotype AB recording the highest frequency in both populations. In addition, PCR-RFLP analysis at the CAST-MspI gene locus showed three genotypes (MM= 0.048, MN= 0.919, NN= 0.032) in the Sahel population whereas only two genotypes (MM= 0.367, MN= 0.633) were observed in the Djallonké population. Results from this study showed that the selected candidate genes were polymorphic in the two studied sheep breeds of Ghana. These results will form the basis for candidate gene association studies in the two sheep breeds.