影响牛生长发育性状的GH基因遗传效应分析

 【目的】研究牛GH基因的遗传多态以及各多态位点对肉牛生长发育性状的影响，以期找到可用于标记辅助选择的分子标记，为下一步分子育种提供依据。【方法】利用PCR-SSCP和PCR-RFLP方法分析了牛GH基因第3内含子、第4内含子、第5外显子、3′非翻译区和5′侧翼区的位点遗传多态，并分析了5个多态位点不同基因型对肉牛体重、体高、体斜长、胸围和肉用指数的基因型效应，以及GH基因的第5外显子、3′非翻译区位点的不同基因型组合基因型效应。【结果】GH基因的第5外显子、3′非翻译区的基因型效应在肉牛体重、体高、体斜长、胸围和肉用指数性状上存在显著差异（P＜0.05），且这2个位点等位基因B为优势等位基因；第5外显子和3′非翻译区的组合基因型ABBB（即组合5）的基因型效应（极）显著(P＜0.05或P＜0.01)高于其它6个组合，且多标记位点的组合效应值极显著高于单标记位点效应。【结论】GH基因第5外显子位点突变等位基因B为体重、体高、体斜长、胸围的优势等位基因。

Study on Genetic Effect on Growth and Development Traits in Beef Cattle

【Objective】The objective of this study was to study the polymorphism of bovine GH gene and relationship between the polymorphisms and the growth traits of beef cattle.【Method】The polymorphisms of bovine GH gene were analyzed by the PCR-SSCP and PCR-RFLP method. Genotypic effects of the 3rd (GH-P1) and the 4th intron (GH-P2), the 5th exon (GH-P3), 3′- flanking region (GH-P4), 5′-flanking region (GH-P5) and composite genotypic effects of the 5th exon and 3′- flanking region of bovine GH gene on growth and development traits were analyzed.【Result】The B allele of the 5th exon (GH-P3) and 3′- flanking (GH-P4) of GH gene had favorable effect on body weight, height at withers, body length, and heart girth, beef production index. Composite GH genotypic effects, ABBB, including B allele of GH-P3 locus and B allele of GH-P4 locus higher than single marker effects of GH-P3 or GH-P4 locus in effect on body weight, height at withers, body length, heart girth, beef production index.【Conclusion】The B allele of the 5th exon of GH gene was favorable allele of body weight, height at withers, body length, and heart girth, beef production index in beef cattle.