Variation in the HSL Gene and Its Association with Carcass and Meat Quality Traits in Yak

Hormone-sensitive lipase (HSL) is involved in the breakdown of triacylglycerols in adipose tissue, which influences muscle tenderness and juiciness by affecting the intramuscular fat content (IMF). This study analyzed the association between different genotypes and haplotypes of the yak HSL gene and carcass and meat quality traits. We used hybridization pool sequencing to detect exon 2, exon 8, and intron 3 variants of the yak HSL gene and genotyped 525 Gannan yaks via KASP to analyze the effects of the HSL gene variants on the carcass and meat quality traits in yaks. According to the results, the HSL gene is highly expressed in yak adipose tissue. Three single nucleotide polymorphisms (SNPs) were identified, with 2 of them located in the coding region and one in the intron region. Variants in the 2 coding regions resulted in amino acid changes. The population had 3 genotypes of GG, AG, and AA, and individuals with the AA genotype had lower WBSF values (p < 0.05). The H3H3 haplotype combinations could improve meat tenderness by reducing the WBSF values and the cooking loss rate (CLR) (p < 0.05). H1H1 haplotype combinations were associated with the increased drip loss rate (DLR) (p < 0.05). The presence of the H1 haplotype was associated the increased CLR in yaks, while that of the H2 haplotype was associated with the decreased DLR in yaks (p < 0.05). These results demonstrated that the HSL gene may influence the meat quality traits in yaks by affecting the IMF content in muscle tissues. Consequently, the HSL gene can possibly be used as a biomarker for improving the meat quality traits in yaks in the future.