常染色体20个短串联重复序列基因座的突变观察与分析

Observation and analysis of mutation of 20 short tandem repeat loci in autosomal

目的调查20个常染色体短串联重复序列(STR)基因座的突变情况。方法采集1 140例亲子鉴定的3 180份血样本,采用STRtyper-21G和Power Plex21系统扩增20个STR基因座分型,共有40 800次等位基因传递,统计各基因座发生突变的频率。结果在20个基因座中发现16个基因座共发生30次突变,平均突变率为0.7×10-3(95%CI 0.5×10-3,1.1×10-3),其中一步突变25次,两步突变3次,三步突变2次;父、母源性突变比率为3∶1,不能确定来源突变6次。结论 STR基因座突变是较为常见的现象,应不断积累STR基因座突变数据,选择其他多态性好、突变率低的遗传标记,以保证检验结论的准确可靠。

Objective To investigate mutation of 20 short tandem repeat（ STR） loci in autosomal. Methods A total of 3 180 bloodstain samples collected from 1 140 parentage confirmed cases were detected by using STRtyper-21 G / Power Plex 21 system and the mutation rates of STR loci were calculated. Results With 40 800 allele transfers,30 mutations were identified at 16 loci. The average mutation rate was 0. 7 × 10^- 3per locus（ 95% CI 0. 5 × 10^- 3,1. 1 × 10^- 3）. Twenty-five mutation events were one-step mutation,three events was two-step mutation,two events was three-step mutation; the ratio of paternal versus maternal mutations was 3∶1,and six indistinguishable mutations were observed. Conclusion STR loci mutation is a common phenomenon. Collecting the data of STR loci mutation and choosing other good polymorphism and low mutation rate of genetic markers will be helpful to ensure that the results are accurate and reliable.