中文摘要：

【目的】观察24个常用STR基因座等位基因突变的现象及特点。【方法】对5084例肯定亲权关系的案例进行分析,筛选等位基因突变事件,确定突变等位基因的来源,统计各STR基因座的突变率,分析突变的规律及其特点。【结果】在24个STR基因座中共观察到172个突变事件,STR基因座的突变率介于0～0.492%。每个突变案例的突变基因座数目为1～3个。突变模式符合逐步突变模式,最多突变步数为四步。父系突变与母系突变比例为3.55：1。【结论】STR基因座等位基因突变现象较为常见。当出现STR基因座突变时,应结合突变的STR基因座信息计算PI值。

英文摘要：

【Objective】 To analyze the phenomena and characteristics of the mutations in 24 short tandem repeat （STR） loci.【Methods】 A total of 5 084 parentage confirmed cases were analyzed.The mutation events were screened.The sources of mutant alleles were ascertained.The mutation rates of STR loci were calculated.The rule and feature of mutation were analyzed.【Results】 A total of 172 mutation events were observed in 24 STR loci.The mutation rate was between 0-0.492%.The number of mutation loci was between 1 and 3 for 1 case.The mutation model was accordant with stepwise mutation model.The maximum mutation step was four.In addition,the ratio of paternal versus maternal mutation was 3.55： 1.【Conclusion】 STR mutation events were common in paternity testing.The information of mutated STR loci should be considered and included when calculating PI value.