【摘要】 目的 评估基于PCR扩增的SNP-STR分型方法在不平衡DNA混合物次要成分分析中的应用价值。方法采用ARMS技术建立SNP-STR荧光多重PCR分型方法，检测中国汉族人群321个无关个体中6个SNP-STR标记的基因型，评估其遗传多态性参数；检测该技术在单一DNA样本中获得成功分型的灵敏度，检测该技术在两个体DNA混合物分析中的有效信息概率，检测该技术在不同比例DNA混合物中获得次要成分基因型的最大混合比例。结果 6个SNP-STR荧光多重PCR技术获得全部基因型的最小DNA输入量为62.5 pg，可从混合比例高达100∶1的两个体混合DNA中获得次要成分的SNP-STR基因型。随着混合比例的增加，主要成分stutter峰信号的增强可能影响次要成分等位基因峰的准确判断。6个标记对中国中部汉族人群混合物分析的信息概率为0.356 2。在法医不平衡混合物检测中，这些SNP-STR标记比STR具有更强的鉴别能力。结论 在法医混合物检测中，SNP-STR标记比STR具有更强的鉴别能力，但不平衡混合物主要成分stutter峰问题可能限制了SNP-STR标记在不平衡DNA混合物次要成分分析中的应用价值。更多还原

【Abstract】 Objective To evaluate the utility of PCR-based SNP-STR typing methods in the analysis of minor components on unbalanced DNA mixtures. Methods SNP-STR fluorescence multiplex PCR typing method was established by ARMS technology. We detected the genotypes of 6 SNP-STR markers in 321 unrelated individuals in the Han Chinese population, and evaluated the genetic polymorphism parameters. We detected(1) the sensitivity of the technique to obtain successful typing in a single DNA sample,(2) the probability of effective information in the analysis of DNA mixtures in two bodies, and(3) the maximum mixing proportion of minor component genotypes in different proportions of DNA mixtures. Results Six SNP-STR fluorescent multiplex PCR techniques yielded a minimum DNA input of 62.5 pg for all genotypes. cSNP-STR genotypes of minor components could be obtained from two body mixed DNA with a mixing ratio of up to 100:1. With the increasing of mixing proportions, the enhanced signal of the major component stutter peak may affected the accurate judgment of the minor component allelic peak. The informative probability of six markers for mixture analysis of Han population in central China was 0.3562. These SNP-STR markers were more discriminative than STR in forensic imbalanced mixture detection. Conclusion SNP-STR markers are more discriminative than STR in the detection of forensic mixed compounds. However, the problem of the major component stutter peak of unbalanced mixtures may limits the utility of SNP-STR markers in the analysis of minor components of unbalanced DNA mixtures.更多还原