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| Genetic Effects of Gonadotropin-releasing Hormone(GnRH) and Growth Hormone (GH) Genes on the Egg Performance in Muscovy Duck(Cairina moschata) |
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Abstract 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.
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Received: 16 September 2011
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