21个非CODIS系统基因座在二联体亲子鉴定中的应用

Application of 21 non-CODIS STR loci in duos parentage analysis

目的评估21个非CODIS系统的STR基因座在二联体亲子鉴定中的应用价值。方法收集207个无关个体样本,采用AGCU21+1荧光标记试剂盒进行检测;根据结果,用计算机随机两两配对构成二联体假想家系;寻找完全符合孟德尔遗传规律,不排除亲权关系和单基因座不符而排除亲权关系的假想家系,统计后者家系中相当于一步突变的例数,计算二联体排除率、累积亲权指数、总排除率。结果构成的21 321个假想家系中有4个家系不排除亲子关系,排除率为0.999 812 392,单基因座不符而排除亲权关系的有60个假想家系,占总家系的0.281%。上述家系再经AGCU22试剂盒检测,结果均可排除亲权关系。结论本文21个非CODIS系统的基因座可作为二联体亲子鉴定的辅助检测,能提高鉴定效率,但不能单独用于二联体的检测。

Obiective To estimate the application value of 21 non-CODIS STR loci in duos parentage analysis. Methods 207 unrelated individuals were genotyped using the AGCU 21 ＋ 1 kit, and then were paired randomly to construct the fictitious duos cases according to the typing results. Those pairs whose typing results were in accordance with Mendel＇ s law of inheritance completely and in accordance with the inheritance law except for single locus were searched from the fictitious combinations, and for the latter combinations, the number that there only was 1 motif difference in length （ i. e. , equivalent to one-step mutation） was counted. Finally, the probability of exclusion, cumulative paternity index and the total probability of exclusion were calculated for these fictitious duos combinations. Results In 21 321 of fictitious combinations, there were 4 pairs not excluded parentage, and the probability of exclusion was 0. 999 812 392, while one STR mismatch was observed from 60 pairs, and the proportion was 0. 281%. For all of the fictitious combinations, the parentage could be excluded after increasing the detection of the AGCE EX22 kit. Conclusion The 21 non-CODIS STR loci can be used as supplement in the duos parentage testing. However, there is a certain risk when use them independently in duos cases.