A novel single nucleotide polymorphism in exon 7 of LPL gene and its association with carcass traits and visceral fat deposition in yak (Bos grunniens) steers

Lipoprotein lipase (LPL) is considered as a key enzyme in the lipid deposition and metabolism in tissues. It is assumed to be a major candidate gene for genetic markers in lipid deposition. Therefore, the polymorphisms of the LPL gene and associations with carcass traits and viscera fat content were examined in 398 individuals from five yak (Bos grunniens) breeds using PCR-SSCP analysis and DNA sequencing. A novel nucleotide polymorphism (SNP)-C -> T (nt19913) was identified located in exon 7 in the coding region of the LPL gene, which replacement was responsible for a Phe-to-Ser substitution at amino acid. Two alleles (A and B) and three genotypes designed as AA, AB and BB were detected in the PCR products. The frequencies of allele A were 0.7928, 0.7421, 0.7357, 0.6900 and 0.7083 for Tianzhu white yak (WY), Gannan yak (GY), Qinghai-Plateau yak (PY), Xinjiang yak (XY) and Datong yak (DY), respectively. The SNP loci was in Hardy-Weinberg equilibrium in five yak populations (P > 0.05). Polymorphism of LPL gene was shown to be associated with carcass traits and lipid deposition. Least squares analysis revealed that there was a significant effect on live-weight (LW) (P < 0.01), average daily weight gain (ADG) and carcass weight (P < 0.05). Individuals with genotype BB had lower mean values than those with genotype AA and AB for loin eye area and viscera fat weight (% of LW) in 25-36 months (P < 0.05). The results indicated that LPL gene is a strong candidate gene that affects carcass traits and fat deposition in yak.