DGAT1 polymorphism K232A in Sahiwal (Indian Zebu) and frieswal (Holstein friesian X Sahiwal crossbred) cattle

The positional candidate gene DGAT1, within QTL of BTA14, harboring a lysine to alanine substitution (K232A) is significantly associated with milk production traits. The present investigation was undertaken to estimate the frequency of the DGAT1 K232A polymorphism in Indian zebu breed, Sahiwal (B. indicus; N=51) and crossbred, Frieswal (HFX Sahiwal; N=126) cattleusing PCR-RFLP technique. Detection of allelic variation at nucleotide positions 10433–10434 of the DGAT1 gene was performed by restriction digestion of a 413 bp PCR product with CfrI. The frequency of A allele in Frieswal and Sahiwal cattle was 0.36 and 0.04, respectively. Although all the three genotypes were observed in Frieswal cattle, however, no animal of AA genotype was found in Sahiwal cattle and only four animals were of heterozygous genotype (AK). The sequences, specific to K and A allele, were submitted to GenBank (JF345253 and JF345254). Because of very high frequency to almost fixed nature of K allele in Sahiwal and other well defined Indian cattle breeds, DGAT1 K232A polymorphism may not be a suitable candidate for selection purpose. Nonetheless, the results could be used to guide association studies between this locus and milk production traits especially in Frieswal.