Comprehensive analyses for genetic diversities of 19 autosomal STRs in Chinese Kazak group and its phylogenetic relationships with other continental populations

Short tandem repeats (STRs) play an essential role in forensic genetics due to their high degree of polymorphisms, wide distributions and easy detection method. In this study, allelic frequencies and forensic statistical parameters of the 19 autosomal STR loci in a Kazak ethnic group were calculated, and its genetic relationships with reference populations were assessed in order to understand population structure better and enrich population genetic data for forensic practice in Chinese Kazak ethnic group. There were 226 identified alleles with the corresponding allelic frequencies ranging from 0.0008 to 0.5295 in the 628 unrelated healthy Kazak individuals in Xinjiang Uygur Autonomous Region. All autosomal STRs were conformed to the Hardy-Weinberg equilibrium after Bonferroni’s correction. The cumulative power of discrimination and the combined probability of exclusion of all the 19 autosomal STRs were 0.999 999 999 999 999 999 999 997 162 and 0.999 999 994 484, respectively. Furthermore, the <i>D</i>_A distances and Fixation index values of pairwise populations, principal component analysis, multidimensional scaling analysis, phylogenetic tree analysis and structure analysis were conducted to probe the genetic relationships between the Kazak group and other reference populations. The population genetic results showed that these 19 autosomal STR loci were characterised by high genetic diversities in the Kazak group. Furthermore, the studied Kazak group had close genetic relationships with the Uyghur group and the Uzbek group. The present results may facilitate understanding the genetic background of the Chinese Xinjiang Kazak group.

短串联重复序列（Short Tandem Repeats, STR）因具有多态性高、分布广泛且检测简便的特点，在法医遗传学领域发挥着至关重要的作用。本研究针对哈萨克族人群的19个常染色体STR基因座，计算了其等位基因频率与法医遗传学统计参数，并评估了该人群与参考群体的遗传亲缘关系，以期更好地解析人群遗传结构，丰富中国哈萨克族群体法医遗传学实践所需的群体遗传数据。本研究纳入新疆维吾尔自治区的628名无关健康哈萨克族个体，共检出226个等位基因，对应等位基因频率范围为0.0008至0.5295。经Bonferroni校正（Bonferroni’s correction）后，所有常染色体STR基因座均符合哈迪-温伯格平衡（Hardy-Weinberg equilibrium）。19个常染色体STR基因座的累计个体识别力与累计非父排除概率分别为0.999999999999999999999997162与0.999999994484。此外，本研究通过群体间两两的D_A遗传距离（D_A distance）与固定指数（Fixation index）值、主成分分析、多维尺度分析、系统发育树分析以及群体结构分析，探究了哈萨克族人群与其他参考群体之间的遗传亲缘关系。群体遗传学分析结果显示，本研究涉及的19个常染色体STR基因座在哈萨克族人群中呈现出较高的遗传多样性。此外，本研究的哈萨克族人群与维吾尔族、乌兹别克族人群具有较近的遗传亲缘关系。本研究结果有助于进一步解析中国新疆哈萨克族人群的遗传背景。