Dominant-genotype Frequency Analysis of Economic Traits Related to SNP Candidate Markers in Three Yak Populations

Background: Yak as a unique domestic animal that has extremely important social value and influence on the local culture and economy in the Qinghai-Tibet Plateau. The current study aimed to evaluate the genotype distribution of a series of economic traits (growth, meat quality and lactation) related to single nucleotide polymorphisms (SNP) in three Tibetan yak populations. Methods: A total of 238 yaks from three populations [Sibu (SB), Chawula (CWL) and Jiali (JL) yaks] including 34 SB, 104 JL and 100 CWL yak individuals were collected. All samples were genotyped for 12 SNP markers by using SNaPshot technology. Result: All loci had abundant polymorphisms in the three populations, except for the Hesx1_G618C locus. The dominant growth-related genotype was MyoD1_C1710T (C/T), which had the highest frequency in the three Tibetan yak populations. However, the growth-related dominant genotypes at UCP2_T1499C (C/T) and CYP4A11_G4806A (G/A) loci were rare genotypes in the three Tibetan yak populations. Results of Hardy-Weinberg equilibrium (HWE) analysis showed that all sites did not deviate from the HWE within the population. This finding indicated that these populations belonged to a natural one without having been subjected to artificial selection on economic traits. Overall, this study provided valuable reference for the future molecular breeding of yak based on the genotype distribution of economic-trait candidate markers in three yak populations in Tibet.