Polymorphism of the prolactin gene and its association with egg production traits in native Chinese ducks

Abstract

As a candidate gene related to egg production, prolactin plays a crucial role in the reproduction of birds. In this study, polymorphism of the prolactin gene was screened in six Chinese native duck breeds (Shanma, Shaoxing, Youma, Jinyun, Jingjiang and the F2 resource population of white Liancheng X white Kaiya) using PCR-SSCP and direct sequencing. The results showed that 12 SNPs were detected: C-213T in the 5,flanking region, A-1842G in exon 2, A-3869G in exon 4 and C-5961T in exon 5, T-295C, C-381A and A-412G in intron 1, T-2231C in intron 2, C-3949T, T-3988G and T-4009C in intron 4 and T-6052A in the 3' flanking region. The C-381A site and C-5961T site can be detected by XbaI and Pst1 PCR-RFLP, respectively. Furthermore, the C-5961T mutation results in an amino acid conversion (Cys to Arg) in the functional domain and affects the existence of a heparin binding site (L-R-R-D-S-H-K). In the F2 resource population, association analysis demonstrated that the C-5961T polymorphism was significantly associated with egg production and egg weight, with the CC genotype associated with higher egg production and bigger egg weight than the CT genotype.

Keywords: Duck, prolactin gene, egg production traits, single nucleotide polymorphism