常染色体STR突变基因座父权指数计算

Paternity Index Calculation in Mutation Autosomal STR Locus

目的概括归纳常染色体STR突变基因座的父权指数计算方法,以在实际检案中应用推广。方法根据目前对常染色体STR基因座突变的认识,用经验递减模型从基因座突变率计算等位基因突变率,分别推导在标准三联体和二联体亲子鉴定中STR突变基因座的父权指数计算式,并举例进行演算。结果总结了在标准三联体鉴定中,只允许假设父突变和既允许假设父也允许母发生突变时,以及二联体鉴定时X和Y的计算式。结论STR基因座发生突变时计算得的父权指数明显低于未发生突变时,提示要检测更多的遗传标记才能使累积父权指数达到认定亲权关系的标准。

Objective To summarize the calculation methods of paternity index of mutational autosomal STR loci for application in paternity casework. Methods Based on the current knowledge of autosomal STR mutation, allele specific mutation probability was estimated from an overall STR mutation rate by using the empirical decreasing model. The calculation formulas of paternity index were derived for trio and duo, respectively. These formulas of PI were illustrated by some examples. Results The calculation formulas of X values and Y values were summarized for trio and duo cases in which either allege father or mother was considered only as one mutation. Conclusion The PI value of mutation case was shown significantly lower than that of no mutation case. It is suggested that more genetic markers should be analyzed for mutation cases to make the CPI achieve the standard of paternity determination.