Abstract: PCR-SSCP and DNA direct sequencing technology were used in this study to identify the polymorphisms of CDS 130—587 bp region of DRD1 gene in individuals of Cherry Valley duck and Xingyi duck, the association between SNPs and growth traits were also performed subsequently. The results showed that 2 alleles named A, B that resulted in 3 genotypes included AA, BB and AB respectively were confirmed in this study. AA genetype was predominant in two duck breeds with frequencies of 0.7416 and 0.5643, respectively, moreover, allele A was predominant compared to allele B for two duck breeds with frequencies of 0.8539 and 0.7204. The polymorphism information content (PIC) were 0.2184 and 0.3217 which belonged to low polymorphism and moderate polymorphism. Chi-square test demonstrated that the genotypes distribution of SNPs locus in the population of Cherry Valley duck was agreement with Hardy-Weinberg equilibrium (P>0.05) and deviated significantly from Hardy-Weinberg equilibrium (P<0.05) in the population of Xingyi duck. The results showed that two SNPs of c.189 T＞C and c.507 T＞A which belonged to synonymous mutation and missense mutation that resulted in the change from serine to arginine. Association analysis showed that the weight of 8 weeks and body length of 12 weeks of Cherry Valley duck for BB genotype individuals were significantly higher than AB genotype (P<0.05). Weight of 10 and 12 weeks and chest depth of 12 weeks of BB genotype individuals were significantly higher than AB and AA genotypes (P<0.05). Results disclosed that the SNPs locus might be an important marker of marker assisted breeding for growth trait of duck.

Key words: duck; DRD1 gene; CDS; PCR-SSCP; SNPs