二组分混合DNA样品STR图谱解释

The interpretation of the STR profile of DNA mixtures from two donors

对混合样品STR图谱的结果进行解释。实验模拟二组分DNA混合样品 ,复合扩增荧光检测 10个基因座 ,比较混合样品谱带 ,计算等位基因峰面积比。结果发现 :二组分DNA混合样品的等位基因数增加 ,样品的混合比例不同就出现峰面积的不平衡。在等位基因峰面积比值与样品组分混合比例接近时 ,可由峰面积比值推断混合样品的混合比例。在混合比例为 1∶2 0时 ,基本上检测不到来自少量混合成分的等位基因 ,表现为单一组分图谱 ;在混合比例为 1∶10时 ,含量低的组分的等位基因峰面积接近与主要组分的“Stutter”峰面积 ,与来自主要组分的等位基因峰面积差异很明显。能检出混合样品中少量成分等位基因的最高混合比例为

For the purpose of interpreting a complex STR profile from DNA mixture , we have analyzed some known mixed DNA samples from two donors by automatic fluorescent detection and multiplex amplification of 10 loci. Through calculating the numbers of the bands , peaks and the ratio of the allele peak area, it was found that the numbers of the peaks of the mixture increased and peak areas of the different alleles in the mixture were imbalance. The proportion of the peak areas of the different alleles approached the ratio of the two DNA parts in the mixture. So the ratio of the two components in a mixture could be estimated from the proportion of their allele peak areas. When the ratio of two components in a mixture was 20∶1, the minor component part could not be detected.When the ratio was 10∶1, the peak area of the minor part was similar with the “stutter” of the alleles of the major part. So that,the highest ratio of the mixture in which both component parts could be detected was 10∶1 .