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

ABSTRACT 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 reaction-restriction 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.

摘要：卵抑素（Ovoinhibitor，OIH）是蛋清中的主要蛋白酶抑制剂。本研究以京江鸭（Jingjiang ducks，JJ鸭）和绍兴鸭（Shaoxing ducks，SX鸭）为研究对象，将OIH作为繁殖性状候选基因，采用实时定量PCR（real-time quantitative PCR）与蛋白质印迹法（Western-Blot）分析其在三个产蛋阶段卵巢中的表达差异模式。为探究这两个鸭群体中OIH基因的多态性，本研究设计了5对引物，通过聚合酶链式反应-限制性片段长度多态性（PCR-RFLP）与DNA混合池测序（DNA pool sequencing）法，检测OIH基因外显子3-5、5-6、14-16及内含子7、9区域的单核苷酸多态性（Single Nucleotide Polymorphisms，SNPs）。结果显示，两个鸭品种卵巢内的OIH表达量均随产蛋进程升高。京江鸭在出雏时与180日龄时的卵巢OIH相对表达量低于绍兴鸭，但在500日龄时则高于绍兴鸭。仅外显子5-6位点存在1个新的单核苷酸多态位点。在两个受试鸭群体中检测到1处变异（389G>A），该变异与多项产蛋性状相关，包括出雏体重、开产日龄、开产蛋重以及72周龄产蛋数。AG基因型与较差的出雏体重相关，同时与更高的开产蛋重、更早的开产日龄以及更高的72周龄产蛋数相关。因此，本研究结果表明，OIH可能是与鸭部分产蛋性状相关的重要候选基因。