Forensic molecular biological applications using single nucleotide polymorphisms (SNPs) regions

在本研究中，我们试图建立合适的方法来检测基因型的单核苷酸多态性（snp），这是有用的法医实践，如个人鉴定和亲子鉴定。首先，我们测试了几种搜索方法，以确定哪一种是最好的。结果表明，等位基因特异性PCR方法便于基因座的选择，而SnapShot方法适用于多重系统。然后，我们从SNP联盟中列出的基因区域外的亚洲人群中选择了51个高度多态性的SNP位点。其中39个位点与32个无亲缘关系的健康日本人存在Hardy-Weinberg平衡。这39个位点在日本具有高度多态性；22个位点的频率低于0.4,14个位点的频率高于0.3。目前，我们正在利用这14个位点中的12个分布在不同染色体上的位点建立一个新的多重SNP分型系统，使用的技术与我们新设计的STR多重分型系统相同。我们还试图建立一种高度敏感的方法，用于DNA高度降解的微小和古老的标本。由于扩增不足，此类标本STR分型结果常为阴性。大多数STR位点的PCR产物为150-300个碱基，而SNP位点的PCR产物可缩短至100个碱基以下。因此，SNP位点具有高效扩增降解DNA的巨大优势。我们几乎可以完成对几个SNP位点的高灵敏度方法的开发。

In this study, we tried to establish the appropriate method to detect the genotypes of single nucleotide polymorphisms (SNPs) which are useful for forensic practice such as personal identification and paternity testing. At first, we tested several methods to search which is the best. We found that the allele specific PCR method is convenient for locus selection, and the SnapShot method is suitable for multiplex system. Then, we selected highly polymorphic 51 SNP loci in an Asian population being outside the region of the gene from those listed in the SNP Consortium. Among them, 39 loci were found to be in the Hardy-Weinberg equilibrium by x^2 method with 32 unrelated healthy Japanese. These 39 loci are highly polymorphic in Japanese ; 22 loci show the lower frequencies over than 0.4, and 14 show them over than 0.3. We are now establishing a new multiplex SNP typing system with the 12 out of these 14 loci, which distribute on different chromosome using the same techniques by which we have succeeded in the newly devised STR multiplex system. We also tried to establish a highly sensitive method for the minute and old specimens where DNA is highly degraded. We often get negative results in STR typing with such specimens because of the insufficient amplification. The PCR products of most STR loci are 150-300 bases, while those of SNP loci can be shortened to less than 100 bases. Therefore, SNP loci have a great advantage of the efficient amplification of degraded DNA. We could almost finish the development of the highly sensitive method for several SNP loci.