藏鸡和隐性白羽鸡GH基因的SNP检测及其与生长性状间的关联分析

 利用改良等位基因特异性PCR（Modified Allele Specific PCR, M-ASP）结合PCR-RFLP以及直接测序方法对藏鸡和隐性白羽鸡生长激素（Growth Hormone, GH）基因内含子4 （Intron4）的一个位点进行了SNP检测，并进行了该基因与藏鸡生长性状的关联分析。检测结果显示，GH基因Intron4的这个位点同时具有M-ASP和SacI-RFLP多态。测序结果表明，该位点发生了C→G的碱基突变，产生了CC、CG和GG三种基因型。两个等位基因和三种基因型在两鸡种中的分布基本一致。其中，基因型CC和等位基因C的频率最高。χ2检验结果表明，基因型频率或者等位基因频率在两鸡种之间没有显著差异（P＞0.05），而分别在两鸡种内部却存在显著（P＜0.05）或极显著（P＜0.01）差异。方差分析结果表明，基因型与藏鸡的2周龄体重等12个生长性状有显著（P＜0.05）或极显著（P＜0.01）关联；基因型CC与藏鸡的7周龄体重存在显著关联（P＜0.05）。这暗示了GH基因是影响藏鸡生长的主效基因或者它与主效基因相关，而该位点的碱基突变可以作为筛选藏鸡高的7周龄体重的分子标记。

SNP Detection in Tibetan Chicken and Recessive Chicken GH Gene and Its Associations with Growth Traits

SNP of growth hormone (GH) gene Intron4 of Tibetan chicken and recessive white chicken were detected by using modified allele specific PCR (M-ASP), PCR-RFLP and sequencing reaction and its associations with growth traits of Tibetan chicken was done. The results indicated that there were M-ASP and SacI-RFLP polymorphisms in Intron4 of GH gene and there was a C/G mutation by DNA sequencing and resulted in 3 genotypes CC, CG and GG. The distributions of three genotypes and two alleles between two chicken breeds were very similar and the frequencies of genotype CC and allele C were highest among them. The results χ2 showed that there were not significant differences in the frequencies of genotypes or alleles between the two chicken breeds (P＞0.05), however, there were significant differences within each of the two chicken breeds (P＜0.05), respectively. The results of analysis of variance showed that genotypes had significant effect on twelve growth traits of Tibetan chicken at 0.05 or 0.01 levels, and there was a positive relationship between genotype CC and body weight of Tibetan chicken at the age of 7 weeks (P＜0.05). It implies that GH gene is the major gene affecting growth traits of Tibetan chicken or it links with the major gene, and the mutation could be used as the molecular genetic marker to select Tibetan chicken for high body weight at the age of 7 weeks.