单亲案亲权鉴定结果判定策略

目的探讨用STR基因座进行单亲鉴定出现矛盾基因座时下结论的策略。方法根据基因频率和遗传规律,推导单亲案亲权鉴定时的非父排除率。根据平均单亲非父排除率和平均突变率,用二项分布公式分别计算出现不同数目矛盾基因座时真父和假父的概率和似然率(亲权指数)。结果对STR共显性基因座,其单亲非父排除率的计算公式为:PEM=∑i=n1pi2(1-pi)2 ∑i

How to draw a conclusion in motherless parentage testing using short tandem repeats as genetic makers

Objective To calculate the exclusion power of STR loci in motherless parentage testing and to discuss how to draw a conclusion if there are inconsistent loci. Methods Based on the law of inheritance and allele frequency, the powers of exclusion of STR loci in motherless parentage testing (PEM) were calculated. Based on the mean PEM and mutation rate of 13 CODIS loci, The probabilities of inconsistence under paternity and non-paternity were calculated respectively according to binomial theorem. Results The PEM of locus having co-dominate alleles could be calculated as:?According to the formula, the average PEM of 13 CODIS was 0.411. Based on the mean PEM and mutation rate, the likelihood ratio of true father to random man (paternity index) was got using binomial theorem. Conclusion The conclusion in motherless parentage testing could be drawn based on the likelihood ratio (paternity index) derived from mean PEM and mutation ratio.