藏绵羊DQA1基因多态性分析  

Polymorphisms of the DQA1 Gene in Tibetan Sheep

作　　者：成述儒[1,2] 罗玉柱[1,2,3] 胡江[1,2] 王继卿[2,3] 刘秀[2,3] 

机构地区：[1]甘肃农业大学动物科学技术学院,兰州730070 [2]甘肃农业大学甘肃省草食动物生物技术重点实验室,兰州730070 [3]甘肃农业大学研究测试中心,兰州730070

出　　处：《中国农业科学》2011年第10期2146-2153,共8页Scientia Agricultura Sinica

基　　金：国家"863"计划项目(2006AA10Z196);国家科技支撑计划课题(2007BAD52B05;2009BAC53B06);甘肃省重点实验室建设计划(085RTSA004)

摘　　要：【目的】研究藏绵羊DQA1基因多态性,确定其等位基因数、核苷酸多态位点、氨基酸多态位点及各等位基因间的遗传关系,同时分析其进化意义。【方法】采用PCR-SSCP方法检测了900只藏绵羊DQA1基因第2外显子多态性;克隆、测序群体内变异产生的各等位基因序列,并分析序列数据。【结果】发现了17个DQA1的等位基因,包括缺失的1种基因,其中5个为发现的新等位基因。16个单倍型序列中发现56个核苷酸多态位点,27个氨基酸多态位点。【结论】藏绵羊DQA1基因第2外显子具有丰富的多态性,群体中可能蕴藏着更多的遗传资源;藏绵羊DQA1基因最初可能是由2个等位基因突变分化成两大类等位基因的;藏绵羊DQA1基因第2外显子序列与牛的DQA1基因第2外显子序列具有较高的同源性,预示绵羊和牛的DQA1基因最早可能来源于它们分歧以前的共同祖先原始序列;DQA1基因在与其相关的特定抗原刺激下发生的免疫应答反应在绵羊和牛上具有相似性;新等位基因C的139位发现了1个新的核苷酸突变位点(A/G),属同义突变;5个新发现的DQA1等位基因遗传关系较近,可能由同一等位基因突变产生。【Objective】 The Tibetan sheep DQA1 gene polymorphism,determine its allele number,nucleotide polymorphism sites,amino acid polymorphism sites,the genetic relationship and evolutionary significance of the alleles were studied.【Method】Variation of DQA1 gene in the 900 Tibetan sheep was investigated by amplification of exon 2 using PCR,followed by single-strand conformational polymorphism（SSCP） analysis,cloning,DNA sequencing and sequence data analysis.【Result】Seventeen alleles were identified including a null allele at the DQA1 locus.Another five alleles were found in the DQA1 gene in this study.Fifty-six nucleotide polymorphism sites and 27 amino acid polymorphism sites were identified in 16 sheep DQA1 gene haplotypes.【Conclusion】The study indicated that a high level of sequence polymorphism existed in Tibetan sheep DQA1 gene,the population may have more genetic resources.Tibetan sheep DQA1 gene may be differentiated into two major categories alleles from two mutant alleles at first.DQA1 gene in Tibetan sheep and cattle has high homology,which indicated that DQA1 gene in sheep and cattle may come from primordial sequences that were present in a common ancestor and have persisted in the sheep and cattle populations since their divergence,and the observation showed that sheep and cattle share similar allelic sequences may be evidence of the need for a specific immune response to a common pathogen.A new nucleotide mutation（A/G） was discovered in 139 site of new alleles C,and it is the synonymous mutation.Five new alleles have near genetic relationship,they maybe came from the same allele by mutantion.

关 键 词：DQA1基因 多态性 PCR-SSCP 藏绵羊 

分 类 号：S826[农业科学—畜牧学]