国人SCN5A基因新的同义突变位点

目的研究中国人心原性猝死相关基因SCN5A突变位点。方法采用聚合酶链反应和DNA测序对1例RQT间期综合征(LQTs)和2例特发性J波患者SCN5A基因进行突变检测。结果①3例患者在国内、外已知的SCN5A突变位点上,均未发现有突变。②发现1个新的同义突变(T990C),位于钠通道α-亚基的DⅠ区段S5～S6胞外环上。结论这个新的同义突变可能通过影响门控性钠通道的跨膜电流而与恶性心律失常的发生相关。

利用位点特异性荧光定量PCR对中国黄果人参的快速鉴定

目的:为生物活性成分含量较高的黄果人参品种建立快速、准确的分子鉴定方法,提高黄果人参的产量及质量稳定性。方法:扩增可能含有种内多态性的人参叶绿体基因片段,通过直接测序比对分析,发掘黄果人参的单核苷酸多态性位点。根据特异性位点设计黄果人参的品种特异性引物,并利用多重及荧光定量PCR对黄果人参与其他人参品种进行区分和鉴定。结果:在ccsA基因的第772个碱基处发现了黄果人参的非同义突变位点(G/A),通过在3′末端引入错配碱基的方式设计了黄果人参的品种特异性引物。在多重PCR体系下只有黄果人参扩增出了217 bp的品种特异性条带,在荧光定量PCR中只有黄果人参有荧光信号产生,等位基因分型分析可实现黄果人参的快速高通量鉴定。结论:研究建立的多重及位点特异性荧光定量PCR体系可以有效实现黄果人参的快速、准确鉴定,为黄果人参的品种鉴定及田间快速筛选提供了一种有效的DNA分子标记技术手段。

Melanocortin-1 receptor gene variants in four Chinese ethnic populations

There is strong relationship between melanocortin-1 receptor (MCIR) gene variants and human hair color and skin type. Based on a sequencing study of MC1R gene in 50 individuals from the Uygur, Tibetan, Wa and Dai ethnic populations, we discuss the occurrence of 7 mc1r variants consisting of 5 nonsynonymous sites (Val60Leu, Arg67Gln, Val92Met, Arg163Gln and Ala299Val) and 2 synonymous sites (C414T and A942G), among which C414T and Ala299Val were reported for the first time. Confirmation and analysis were the made of 122 individuals at three common point mutations (Val92Met, Arg163Gln, A942G) using PCR-SSCP. The frequency of Arg163Gln variant varies in the four ethnic populations, with percentage of 40%, 85.0%, 66. 2% and 72.7%, respectively, while those of Val92Met and A942G are roughly similar in these four populations. The different environments, migration and admixture of various ethnic groups in China might have impact on the observed frequency of Arg163Gln.