【作者】 黄毅；

【导师】 刘益平； 何大乾；

【作者基本信息】 四川农业大学 ， 动物遗传育种与繁殖， 2009， 硕士

【摘要】 黑素皮质素受体家族包括MC1R、MC2R、MC3R、MC4R和MC5R,是目前所知的最小的G蛋白偶联受体亚家族,它们均属于A类7个跨膜α螺旋G蛋白受体,是一系列小基因的产物。作为其中的家族成员基因,MC4R基因由332个氨基酸残基组成,具有七次跨膜结构,在肾上腺、性腺、脾、脂肪和脑等组织表达,MC4R基因具有介导Leptin蛋白的功能,是一个调节能量与能量动态平衡的重要的信号分子,其主要作用是控制食欲、体重、能量代谢。本研究采用PCR-SSCP和DNA测序的方法,对朗德鹅、四川白鹅和皖西白鹅三个品种共175个个体进行了MC4R基因外显子多态性的研究,结果表明,MC4R基因外显子存在M、N两个多态位点,分别位于G108 A、C 627 T,并且在各个品种中都存在多态性,两个SNP位点均为同义突变。χ~2适合性检验表明:位点M、N已经达到Hardy-Weinberg平衡状态(P＞0.05)。研究同时对朗德鹅94个个体进行相关分析,各位点基因型与屠体性状关联分析得知:M位点各基因型与屠体重(CW)、胸肌率(BMP)和腿肌率(LMP)有显著(P＜0.05)影响,N位点各基因型与活重(BW)、屠体重(CW)、半净膛重(SEW)和全净膛重(EW)有显著(P＜0.05)影响。与产肝性状关联分析得知:N位点各基因型与肝体比(LBR)和肝屠比(LCR)显著(P＜0.05)影响。两位点对鹅的脂肪沉积性能均无显著影响,三种基因型效应差异都不显著(P＞0.05)。研究还通过对各复合位点与朗德鹅屠宰性状、产肝性状和脂肪沉积性状进行相关分析,发现H3H3基因型具有最高的活重(BW)、屠体重(CW)、半净膛重(SEW)和胸肌重(BMW),与其他单倍型组合差异性显著;H4H4基因型具有最高的肝重(LW)、肝体比(LBR)、肝屠比(LCR)和腹脂率(AFR)与其他单倍型组合差异性显著,说明H3H3和H4H4型是最佳基因型组合。本实验初步推断MC4R基因可能是影响鹅屠体性状的主效基因或与主效基因连锁,且N位点可能是影响鹅MC4R基因产肝性状的主要位点。更多还原

【Abstract】 Melanocortin Receptors family(MCRs,including MC1R、MC2R、MC3R、MC4R and MC5R) is the smallest G-protein-coupled receptor subfamily.All of the members are the productions of a series small genes which belong to species Aα-Helix G-protein receptor including 7 transmembrane domains.As one of MCRs,MC4R gene codes 332 amino acids residues constructing 7 transmembrane domains,which expresses in adrenal gland,gonad,spleen,fatty,brain and other tissues.MC4R gene is an important signaling molecule mediating leptin protein to adjust energy and energy development balance,in order to control the appetite and energy metabolism.In this study,3 breeds(including Landes geese,Sichuan white geese and Wanxi white geese 175 individuals)were used to analyze the polymorphism of the exon of MC4R gene by PCR-SSCP and DNA sequencing.Results indicated that there were two mutation sites named M(C 108 T) and N(G 627 A),which were both samesense mutations found in each geese line.Statistical results showed that the polymorphic sites fitted with Hardy-Weinberg equilibrium for site M and N(P＞0.05).In this study,94 Landes geese were used to statistics analysis,and the results showed that in slaughter traits,there were significant differences(P＜0.05) for carcass weight(CW),breast muscle percentage(BMP) and leg muscle percentage(LMP) in M site,and significant differences(P＜0.05) for body weight(BW),carcass weight(CW), semi-eviscerated weight(SEW) and eviscerate weight(EW) in N site.In addition in N site there were significant differences(P＜0.05) for liver and body ratio(LBR) and liver and carcass ratio(LCR) in fatty liver performance.The two sites had no effect on the fat deposition performance,which means there was no significant difference(P＞0.05) among the three genotypes.The statistics analysis results of haplotype on carcass traits,fatty liver and fat deposition performance showed that there were the highest body weight(BW),carcass weight(CW),semi-eviscerated weight(SEW) and breast muscle weight(BMW) in diplotype H3H3,liver weight(LW) liver and body weight ratio(LBR),liver and carcass weight ratio(LCR) and abdominal fat weight(AFR) in diplotype H4H4,and there were significant differences with other genotypes,from which could be concluded that H3H3 and H4H4 genotype were the best diplotype.It could be concluded from the results that MC4R gene might be the major gene affecting the meat traits of geese or linking with the major gene,and the N site may be the major site affecting the fatty liver performance of geese.更多还原