促性腺激素释放激素基因(GnRH)和生长激素基因(GH)对番鸭产蛋性能的遗传效应分析

促性腺激素释放激素(GnRH)和生长激素(GH)分别是下丘脑-垂体-性腺轴(HPG)与GH/IGF轴分泌的激素,共同参与调控动物的繁殖性能。本研究以白羽番鸭(Cairina moschata)RF系为实验材料,采用PCR-SSCP技术进行基因分型,同时建立适合的线性统计模型,分析基因型与产蛋性能的关联性。结果表明,GnRH基因5’调控区检测到3种基因型AA/AB/BB,经测序比对AA型与BB型相比发生G→A突变,不同基因型与300日龄产蛋数和最大连产天数均显著相关(P<0.05),与开产日龄无显著相关(P>0.05);GH基因内含子3检测到3种基因型CC/CD/DD,经测序比对CC型与DD型相比发生A→G突变,不同基因型与最长连产天数显著相关(P<0.05),与300日龄产蛋数和开产日龄均无显著相关(P>0.05)。两个基因发挥作用的方式主要为加性效应,GnRH基因对300日龄产蛋数和最大连产天数的加性效应值分别为-3.53和-3.33,GH基因对最大连产天数的加性效应值为-2.44。推测GnRH和GH基因是与繁殖主效基因紧密连锁的标记基因。

Genetic Effects of Gonadotropin-releasing Hormone (GnRH) and Growth Hormone (GH) Genes on the Egg Performance in Muscovy Duck(Cairina moschata)

Gonadotropin-releasing hormone (GnRH) and growth hormone (GH), which control the reproductive performance of animal, are secreted by hypothalamus pituitary gonadal axis and GH/IGF axis. The single nucleotide polymorphism of GnRH and GH genes was detected for the association with egg performance in white muscovy duck(Cairina moschata) RF line which came from Putian Guangdong Wenshi Poultry Co., Ltd.. PCR-SSCP method was used for identification of genotypes. The results showed that three genotypes AA, AB and BB were found in GnRH gene and a mutation G→A was found by DNA sequencing. Three genotypes CC, CD and DD were found in GH gene and a mutation A→G was found by DNA sequencing. Chi-square test indicated that the two polymorphism sites fitted Hardy-Weinberg equilibrium (P>0.05).The frequency of A/B alleles in the population was for GnRH 0.675 and 0.325, and for GH 0.667 and 0.333. GnRH genotype had been showed a significant difference in the egg number of 300 d (P<0.05),but GH genotype had not. Both of genes genotype had significant differences in the highest clutch days but no significant difference in the age at the first egg (P>0.05). The general linear model(GLM) analysis results showed that both of GnRH and GH genes showed mainly in the pattern of additive effect and all the dominant effects were not significant. The additive effect of GnRH gene in the egg number of 300 d and the highest clutch days were -3.53 and -3.33, respectively. The additive effect of GH gene in the highest clutch days was -2.44. It implies that the GnRH and GH genes can be candidate genes locus or linked mark to the major gene, which affect the laying traits significantly in Muscovy duck.