Polymorphism of beta-lactoglobulin gene in Indian goats and its effect on milk yield

Polymorphism in the β-LG gene in the Indian goat was investigated by the SDS-PAGE and PCR-RFLP method. SDS-PAGE was carried out in 1098 samples belonging to 8 different breeds of Indian goats. The electrophoretic pattern in the β-LG locus showed the presence of AA and AB genotypes with frequencies of 0.81 and 0.19,0.89 and 0.11, 0.50 and 0.50, 0.80 and 0.20, 0.84 and 0.16, 1.00 and 0.00, 0.98 and 0.02 and 0.950 and 0.050 in Jamunapari, Barbari, Marwari, Sirohi, Jakhrana, Beetal, Local UP and Local MP goats, respectively. A total of 358 individuals belonging to 13 different genetic groups were analyzed by the PCR-RFLP method. The amplified product was observed as 426 bp and the restriction digestion with SacII revealed three genotypes, namely S₁S₁, S₁S₂ and S₂S₂ at the β-LG locus. The frequency of the S₂S₂ genotype ranged from 0.42 to 1.00 in the population. An analysis was carried out in Jamunapari and Barbari goats to observe the effect of the β-LG genotype on 90-day milk yield. Least squares analysis of data showed that β-LG AA animals had higher milk yield than the β-LG AB genotype in both breeds (P < 0.01).