Analysis of polymorphism at the beta-lactoglobulin locus in vechur and dwarf cattle of Kerala using PCR-RFLP

摘要

Investigations were carried out on the genetic polymorphism at the beta-lactoglobulin (beta-LG) locus in Vechur and nondescript dwarf cattle of Kerala, using the PCR-RFLP method. A total of 92 Vechur cattle and 34 dwarf cattle were studied. A 262 bpregion of the beta-LG gene spanning from exon IV to intron IV that contains the nucleotide substitution diagnostic of A or B allele was amplified by polymerase chain reaction and polymorphism was detected by digestion of the PCR product with HaeIII enzyme. The analysis revealed two alleles; namely, allele A (153 and 109 bp) and allele B (109, 79 and 74 bp). The frequencies of beta-LG-A and beta LG-beta alleles were 0.35/0.65 and 0.19/0.81 for Vechur and dwarf cattle, respectively. The frequencies of different genotypes in two types of cattle were AA: 0.11, 0.03; AB: 0.48, 0.32 and BB: 0.41, 0.65, respectively. The observed numbers of the three beta-LG genotypes were not significantly (p > 0.05) different from the expected numbers on the basis of Hardy-Weinberg equilibrium. It was important to note that the frequency of the desirable B allele was very high in both the cattle types investigated.