Abstract：The current study was aimed to analyze the association of promoterⅢ in Acetyl-CoA carboxylases-α gene(ACACA) with milk traits in Laoshan dairy goat(Capra hircus). Denaturing high-performance liquid chromatography (PCR-DHPLC) and direct sequencing were applied to identify SNPs in promoter Ⅲ of ACACA gene in Laoshan dairy goat population containing 174 samples, and least square method was performed to evaluate the association of polymorphism in promoter Ⅲ with milk traits. The SNPs have been identified as followed, B/D at 1206 bp, A/C at 1255 bp, M/N at 1322 bp. The distribution of alleles and genotypes in both Group F and Group P was not balanced, but still under Hardy-Weinberg equilibrium. The variation between two genotypes was not significant in the whole population, only the difference between different herbs existed. Further, the difference between different genotypes were analyzed in Group F and Group P, respectively. The 1206 site in F group, allele B had a positive effect on protein , lactose and non-fat rate, and the difference between genotypes BB and BD was statistically significant for protein rate and fat rate (P<0.01), for non-fat and milk density (P<0.05). The substitution effects for protein, lactose and non-fat rate were significant (P<0.05). While in P group, the difference between genotypes BD and BB for all milk traits was not significant (P>0.05). Allele N was the dominant allele for lactose rate，while this was the negative allele for milk yield at 1322 site in F group, and the difference between genotypes MN and MM was significant for milk yield (P< 0.01) and for lactose rate(P<0.05). The substitution effects for lactose rate and milk yield were 0.12% and －52.22 kg (P<0.01), respectively. In P group, allele M was the dominant allele for protein rate, lactose rate, non-fat and milk density, the difference between genotypes MM and MN was significant for protein rate, lactose rate, non-fat and milk density (P<0.05). The substitution effects for lactose rate and non-fat were －0.25%, －0.44%(P<0.05), respectively. This study shows that the same alleles of promoter PⅢ in ACACA gene vary in their effects in different breeding groups, for milk protein rate, lactose rate, non-fat material rate, milk density and 300 d milk yield.
