Molecular Characterization of Genetic Polymorphisms in Kappa Casein Gene (Exon 4) Among Sudanese Desert Goat

Abstract

The present study aimed to identify the genetic polymorphism of kappa casein gene (exon 4) among Sudanese desert goat in South Darfur State. DNA was extracted from blood samples obtained from unrelated goats (n = 68) from different herds. Forward (5’-tcccaatgttgtactttcttaacatc-3’) and reverse (5’-gcgttgtcctctttgatgtctccttag-3’) primer pair was designed to amplify the whole exon 4 of CSN3 in addition to partial promoter intronic regions. Successful amplicons revealed band of about 700 bp, which was subjected to digestion with restriction endonuclease HaeIII. Two electrophoresis patterns representing the homozygous (AA) with two bands of 450 and 250 bp, and the heterozygous (AB) with three bands of 700, 450 and 250 bp were observed. The genotypic frequencies for AA and AB were 66.20 and 33.80%, respectively. While the allelic frequencies were 83.10 and 16.90% for A and B alleles, respectively. The chi-square test (χ2 = 2.81, P > 0.05) confirmed the validity of Hardy–Weinberg equilibrium for the population. It could be concluded that, because of the association between the polymorphism of kappa casein gene and milk production traits and cheese making, studies and research works are needed to improve the selection criteria.

Keywords: genetic polymorphism, kappa casein, local goat, PCR-RFLP, Sudan