The Differential Expression and Snp Analysis of the Ovoinhibitor Gene in the Ovaries of Laying Duck Breeds (Anas Platyrhynchos)

Ovoinhibitor (OIH) is the main proteinase inhibitor in the egg white. In the present study, real-time quantitative PCR and Western-Blot were used to analyze different expression pattern of OIH in ovaries as a candidate gene of reproductive traits in Jingjiang ducks (JJ ducks) and Shaoxing ducks (SX ducks) during three laying stages. To study the polymorphism of the OIH gene in those two duck populations, we designed five pairs of primers to detect SNPs of exon 3-5, 5-6, 14-16 and intron 7, 9 of the OIH gene by polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP) and DNA pool sequencing methods. The results showed that OIH expression increased during the laying stage in the ovaries of both duck breeds. The relative expression levels of OIH in the egg at hatch and 180days of age were lower in JJ ducks than in SX ducks, but higher in JJ ducks than SX ducks at 500 days of age. Only exon 5-6 locus had a novel SNP. One variation (389G>A) was detected in the two tested duck populations and it was associated with some laying traits, such as body weight of hatch, age at first egg, weight at first egg, egg number at 72weeks of age. The AG genotype was associated with inferior body weight of hatch and superior weight at first egg, age at first egg and egg number at 72weeks of age. Therefore, these results suggest that OIH may be a strong candidate gene related to some laying traits in ducks.