Polymorphism in exon 7 of β-lactoglobulin and exon 5 of Stearoyl coenzyme A desaturase genes in goats

Kerala has two native breeds of goats namely Attappady Black and Malabari. These breeds, along with Malabari crossbreds formed the material for study. Reported polymorphisms in exon 7 of β-Lactoglobulin (βLG) and exon 5 of stearoyl soenzyme A desaturase (SCD) were screened to find out the genotypic and allelic frequencies in particular goat populations and to observe an association if any, with milk protein and fat percentage in goat milk. DNA was isolated from blood samples of 347 animals representing three goat populations. Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) was conducted for two loci namely βLG and SCD. PCR-RFLP of βLG gene fragment using SacII enzyme revealed three genotypes namely, CC, CD and DD. The frequency of CC genotype was very low in all the populations, whereas DD genotype had high frequency in Attappady Black and crossbred populations (0.58 and 0.67, respectively) and CD genotype was high in Malabari populations (0.70). Frequency of D allele (0.76) was higher than C allele (0.24) in all three populations. PCR-RFLP of βLG gene revealed significant (P<0.01) association between genotypes and genetic groups of goats. However, no association was established between genotypes and milk protein percentages. PCR-RFLP of exon 5 of SCD gene using RsaI enzymes showed a monomorphic banding pattern, supporting the reports that there is less genetic variation in the coding region of SCD gene in goats.