【作者】 高岩松；

【导师】 王保捷；

【作者基本信息】 中国医科大学 ， 法医学， 2007， 硕士

【摘要】 前言谷氨酸(Glutamate，Glu)为体内重要兴奋性氨基酸，是哺乳动物中枢神经系统中含量最丰富的兴奋性神经递质，参与神经系统多种重要功能的调节。Glu在神经末梢中储存于囊泡中，在突触传递中，Glu以胞吐形式释放，进而激活位于突触后的Glu受体。Glu受体激活后，再使相应的效应子发挥作用，从而改变细胞的膜电位和生化状态。Glu对于学习、记忆及神经传导等有着重要的作用。根据其与效应子间功能偶联的关系，Glu受体分为2种主要类型：离子型谷氨酸受体(ionotropic glutamate receptor，iGluR)和代谢型谷氨酸受体(metabotropic glutamate receptor，mGluR)。根据受体选择性激动剂的不同，将iGluR分为N-甲基D-天冬氨酸(N-methyl-D-aspartate，NMDA)受体、a-氨基3-羟基5-甲基4-异恶唑(AMPA)受体和海人藻酸(kainate，KA)受体，后两种受体常合称为非NMDA受体。KA受体、AMPA受体通道维持平时的信息传递，而NMDA受体通道只在学习记忆过程中才开启，因此被认为是学习记忆中的关键物质。谷氨酸iGlu受体是由四个或五个亚基组成的寡聚体。每个NMDA受体上含有2个Glu和2个甘氨酸结合识别位点，Glu和甘氨酸均是受体的特异性激活剂。NMDAR包含2种亚基，NR1和NR2。NR2亚基分为4型：NR2A、NR2B、NR2C、NR2D。其中NR1可单独形成功能性纯寡聚体，但NR2亚基却不具备该功能。NNMDA受体在大脑皮层广泛分布，但密度最高的是海马CA1区，CA3区和齿状回为中等水平。谷氨酸NMDA受体中的GRIN2A亚基，又称NMDAR2A或GR2A，基因位于16p13.2，全长6293bp。GRIN2A基因存在多个变异点且具有遗传多态性，这些多态位点散布于各外显子和内含子内，其中SNP位点众多。本研究选择NMDA受体中的GRIN2A亚基基因3号内含子中的2个SNP位点rs17750303(A→C)和rs837690(A→G)，调查其在中国汉族群体中的遗传多态性，并探讨其应用。材料与方法根据目标序列设计引物，应用PCR技术扩增GRIN2A基因的SNP位点rs17750303和rs837690，利用BstNⅠ限制性内切酶进行消化，以聚丙烯酰胺凝胶电泳分离结合银染显带的方法，对139例中国北方汉族个体进行了基因分型。结果中国北方汉族139例血液样品，通过常规电泳法检测其基因型，rs17750303位点检出AA型31例，CA型60例，CC型48例。计算得出C等位基因的频率为0.561，A等位基因的频率为0.439。rs837690位点检出GG型51例，GA型50例，AA型38例。计算得出G等位基因的频率为0.547，A等位基因的频率为0.453。讨论通过电泳检测分型的方法对139例中国北方汉族血液样品进行了GRIN2A基因rs17750303和rs837690位点的遗传多态性检测，基因型频率分布符合H-W定律。rs17750303位点在中国北方汉族人群的DP值为0.645，H值为0.493，EPP值为0.187。rs837690位点在中国北方汉族人群的DP值为0.661，H值为0.496，EPP值为0.186。它们在中国北方汉族群体隶属高等鉴别能力的遗传标记系统。结合北美群体的数据，经过统计学X~2分析，rs17750303多态性分布在中国北方汉族群体与北美群体间有显著性差异(P＜0.05)。结论1.GRIN2A基因2个SNP位点rs17750303和rs837690在中国北方汉族群体中具有较好的遗传多态性分布，在法医学个体识别和亲子鉴定中具有较高的应用价值。2.GRIN2A基因rs17750303位点可作为人类遗传学研究的指标之一。更多还原

【Abstract】 InductionGlutamate (Glu) is a very important excitability amino acid in human’s metabolism,and it’s the most abundant excitability nerve matter in the nerve centre of mammalian. Glu participates in many important functuinal adjust of nerve system. When the glutamate receptor is activated,it may impulse the effect-actor to change the potential of cell membrance. Glu makes role effect in human study memory and nerve transmit.Glutamate receptor is divided into two kinds: ionotropic glutamate receptor (iGluR) and metabotropic glutamate receptor (mGluR). According to the difference of activator, iGluR is divided into NMDAR (N-methyl-D-aspartate receptor) AMPAR KAR (kainite receptor).NMDAR includes two parts: NR1 and NR2. NR2 can be divided into 4 kinds NR2A NR2B NR2C NR2D.The NR2A is also called GRIN2A. GRIN2A gene is located in16p13.2 and is 6293bp long. There are so many variance which can be inherited in GRIN2A gene and the number of SNP is large.Our research is mainly about the polymorphism and significance of GRIN2A gene’s two SNP: rs17750303 (A→C) and rs837690 (A→G) .These two SNP are located in the 3 intron of GRIN2A gene. We investigate the gengtic polymorphism of the 2 SNP in Northern Chinese Han. Further more approach the association between rs17750303-rs837690 and schizophrenia.Material and MethodsOrdering the primer by analyzing the aim-sequence, we use PCR method to amplify the GRIN2A gene rs17750303-rs837690 locus,and use BstNI restriction endonucleases digest them, by PAGE followed silver stain. We genotype the genes of 139 Chinese han.ResultIn 139 Chinese han individuals, we find two alleles and three genotypes in each SNP locus. Rsl7750303: homozygote AA was 31 individuals, its frequency was 0.223; homozygote CA was 60 individuals , its frequency was 0.432;homozygote CC was 48 individuals, its frequency was 0.345.Allele C frequency was 0.561 , allele A frequency was 0.439.Rs837690: homozygote AA was 38 individuals, its frequency was 0.273; homozygote GA was 50 individuals, its frequency was 0.360;homozygote GG was 51 individuals, its frequency was 0.367.Allele G frequency was 0.547 , allele A frequency was 0.453.DiscussionThis study investigated the GRIN2A gene 2 SNP(rs17750303 rs837690) polymorphism in the Chinese Han, by statistics analysis, and the data obey the Hardy-Weinberg regulation. According to the rs17750303 genotype and allele frequency in Chinese Han data, we conclude that the DP value is 0.645, the H value is 0.493, the EPP value is 0.187 . According to the rs837690 genotype and allele frequency in Chinese Han data, we conclude that the DP value is 0.661, the H value is 0.496, the EPP value is 0.186 . This loci is highly discrimination power genetic system.To compare the Chinese Han individual with the Northern American individualof GRIN2A gene rs17750303, the allele frequency distribution has a obviouslystatistic difference, P<0.05.Conclution1. Our study report the genotype frequency distribution of GRIN2A gene rs17750303 and rs837690 locus in Chinese Han individuals, and provide the necessarily data in forensic medicine. The Chinese han individuals have highly discrimination power and EPP.2. The GRIN2A gene rs17750303 locus frequency has obviously difference between the Chinese Han individual and the Northern American individual (P<0.05).更多还原