亲子鉴定中二联体鉴定结果判定标准的探讨

A case of motherless paternity identification and some suggestions on drawing a conclusion from duo paternity test

目的探讨二联体亲子鉴定判定标准及结论描述并报道假定父亲与真实生物学父亲为同胞兄弟亲子鉴定1例。方法检测15个短串联重复序列基因座,包括13个CODIS基因座以及PentaE、PentaD。统计经三联体认定的二联体组合310例,分别采用上海司法部法庭司法科学技术研究所推荐的基因座频率、北京汉族基因频率和本实验室基因频率计算认定二联体的联合父权指数;统计69例排除案例的二联体组合不符合的基因座个数。结果 310例认定的二联体组合采用不同的基因座频率计算具有不同的联合父权指数,310例认定的二联体父权指数变化范围在101~1011之间,69例排除二联体组合不符合基因座的个数在2~13个之间。结论应用15个基因座进行亲子鉴定时,建议将二联体亲子鉴定结论的描述统一规范为排除或不排除,即检测发现三个或三个以上不符合基因座时,可以排除亲子关系;当15个短串联重复序列基因座都符合,且父权指数大于4000,不可以排除亲子关系;似然比小于4000时,建议补充另一方的样本或增加检测的基因座的个数。

Objective To report a case of motherless paternity,whose biological father and alleged father are brothers,by which some suggestions on drawing a conclusion of motherless paternity test were made.Methods 15 STR,including D3S1358,TH01,D18S51,D5S818,D13S317,D7S820,D16S539,CSF1PO,VWA,D8S1179,TPOX,FGA,Penta D,were genotyped in 310 families,among which a special case of motherless paternity were identification.By recording the genotype and calculating the combined paternity index（CPI）,the loci in 69 exclusion cases were numbered and the CPI span of 310 motherless paternity were identification.Results The CPI value are varied with the STR loci allele frequency.The CPI value of 310 motherless paternity identification were in the range of 101~1011.The unmatched loci number of 69 exclusion cases were in the range of 2 to 13.Conclusion The conclusion of duo paternity identification should be described as inclusion or exclusion when using 15 STR loci,which more than 3 loci were found to be unmatched,it should be exclusion,while no loci unmatched and the CPI value is more than 4 000,it should be inclusion.When the CPI is more than 4000,more STR loci should be detected to make a correct conclusion.