18个X-STR基因座在中国广东汉族的遗传多态性研究

Genetic Polymorphism of 18 X-STR Loci in Guangdong Han Population

为评估18个X-STR(chromosome X short tandem repeat, X-STR)基因座在法医物证学中的应用价值,收集中国广东汉族共398例无关个体(男性及女性样本各199例)血样,利用DNATyper?X19试剂盒对该人群进行遗传多态性调查。18个X-STR位点共检出148个等位基因,其基因频率在0.0013~0.7839之间,其中多态性信息含量(polymorphism information content, PIC)最为丰富的基因座是DXS8377(PIC=0.9018)。个体识别能力(discrimination power, DP)在男、女群体中分别为0.5514~0.9845、0.3570~0.9090,累计个体识别能力(total discrimination power, TDP)在男女群体中均大于0.9999999999;平均排除概率(mean exclusion chance, MEC)在三联体及二联体中分别为0.3218~0.9018、0.2001~0.8276,在二联体案件中的累计平均排除概率为0.99999935325,在三联体案件中的累计平均排除概率为0.99999999897。结果表明DNATyper?X19试剂盒中所包含的18个X-STR累计平均排除概率可以满足案件检验需求,18个X-STR的基因频率数据可为X-STR检验提供数据支撑。

To evaluate the value of 18 X-STR(chromosome X short tandem repeat, X-STR) loci in forensic evidence, a total of 398 blood samples(male 199 and female 199) from unrelated Guangdong Han population were collected and carried out a survey of genetic polymorphism for the loci by DNATyper?X19 kit. In this study, 148 alleles were observed, and the corresponding allele frequencies ranged from 0.0013 to 0.7839. Locus DXS8377 was the most informative marker(PIC=0.9018). The discrimination power(DP) values ranged from 0.5514 to 0.9845 in females, and 0.3570 to 0.9090 in males, and the total discrimination power(TDP) values in both groups were more than 0.9999999999.The mean exclusion chance(MEC)values in trio and duo ranged from 0.3218 to 0.9018, 0.2001 to 0.8276, respectively. The combined mean exclusion chance was0.99999935325 in duo cases(CMECduo), and 0.99999999897 in trio cases(CMECtrio). Our results show the CMEC of 18 X-STRs included in DNATyper?X19 kit multiplex system showed potential as an effective means for identifying complicated parental cases, allele frequencies of 18 X-STR loci in Guangdong Han population can be used in the parental cases.