Abstract The polymorphisms of prolactin (PRL) and growth hormone (GH ) genes were detected using PCR-RFLP and PCR-SSCP, respectively. The association between the two genes (PRL and GH ) and egg performance of Gaoyou duck were analyzed. The results showed: ①Three genotypes AA, AB and BB were found in PRL gene by PCR-RFLP. Frequencies of allele A and B were 0.226 and 0.774. A mutation T→C at the position of 1 326 bp (PRL intron 1) of the PRL gene in Gaoyou duck was found by DNA sequencing. Three genotypes CC, CD and DD were found in GH gene with the preponderant gene D frequency of 0.778 and the gene C frequency of 0.222. The mutations C→T at the position of 3 701 bp (GH extron 4) was found by DNA sequencing. ②The highly significant association between PRL polymorphism and egg weight (30-weeks) was observed (P <0.01). Three significant associations were found: for PRL and double-yolk percentage(P <0.05), GH and the highest clutch days (P <0.05), GH and double-yolk percentage (P <0.05), respectively.
