Forensic characterisation and polymorphism analysis of 16 X-chromosomal STRs in the Jining Han population in Eastern China

X-chromosomal short tandem repeats (X-STRs) are a useful supplementary approach to analysing autosomal markers in forensics and kinship studies; such markers are not well-characterised in many populations. To investigate population genetic polymorphism and forensic characterisation of 16 X-STRs in the Jining Han population, and analyse genetic relationships with other Chinese populations. Allele frequencies for 16 X-STR loci were obtained from a sample set of 527 unrelated individuals from the Jining Han population. Population genetic analyses of Jining Han and another 10 reference populations were conducted using phylogenetic tree, principal component analysis and multidimensional scaling. We detected 149 alleles, with frequencies ranging from 0.0013 to 0.8242. The combined powers of discrimination in males and females were 0.999999997194774 and 0.999999999999995, respectively. The combined mean exclusion change (MEC)_Krüger, MEC_Kishida, MEC_Desmarais, and MEC_{Desmarais Duos} values were 0.999974632649096, 0.999999976997582, 0.999999977013201, and 0.999993755768423, respectively. We detected relatively high genetic homogeneity in populations with similar ethnic or geographic origins, and a close relationship between the Jining Han and Beijing Han populations. The present findings indicate that the 16 X-STR loci examined are highly polymorphic in the Han population of Jining, providing useful information for forensic science and population genetics studies.

X染色体短串联重复序列（X-chromosomal short tandem repeats, X-STRs）是法医物证学和亲缘关系研究中分析常染色体标记的有效补充手段，但目前多数人群中该类标记的特征尚未得到充分阐明。为探究济宁汉族人群中16个X-STR基因座的群体遗传多态性及法医学应用特征，并分析其与其他中国人群的遗传亲缘关系，本研究从济宁汉族人群中招募527名无关个体作为研究对象，获取了16个X-STR基因座的等位基因频率数据。随后采用系统发育树、主成分分析及多维标度法，对济宁汉族人群及另外10个参考人群开展群体遗传分析。本研究共检出149个等位基因，等位基因频率范围为0.0013至0.8242。男性与女性的累计个体识别力分别为0.999999997194774和0.999999999999995。克鲁格法累计平均排除概率（MEC_Krüger）、岸田法累计平均排除概率（MEC_Kishida）、德马雷法累计平均排除概率（MEC_Desmarais）以及德马雷双人法累计平均排除概率（MEC_{Desmarais Duos}）的数值分别为0.999974632649096、0.999999976997582、0.999999977013201和0.999993755768423。研究结果显示，具有相似种族或地理起源的人群呈现出较高的遗传同源性，且济宁汉族人群与北京汉族人群的遗传亲缘关系较为紧密。本研究表明，本次检测的16个X-STR基因座在济宁汉族人群中具有高度遗传多态性，可为法医学研究及群体遗传学分析提供有价值的参考依据。