Table2_Forensic analysis and sequence variation of 133 STRs in the Hakka population.XLSX

Introduction: Short Tandem Repeats (STRs) are highly valuable genetic markers in forensic science. However, the conventional PCR-CE technique has limitations, and the emergence of massively parallel sequencing (MPS) technology presents new opportunities for STR analysis. Yet, there is limited research on Chinese population diversity using MPS.
Methods: In this study, we obtained genotype data for 52 A-STRs and 81 Y-STRs from the Hakka population in Meizhou, Guangdong, China, using the Forensic Analysis System Multiplecues SetB Kit on the MGISEQ-2000 platform.
Results: Our findings demonstrate that these 133 STRs are highly efficient for forensic applications within the Meizhou Hakka population. Statistical analysis revealed Hobs values ranging from 0.61306 to 0.91083 and Hexp values ranging from 0.59156 to 0.91497 for A-STRs based on length polymorphism. For sequence polymorphism, Hobs values ranged from 0.61306 to 0.94586, and Hexp values fluctuated between 0.59156 and 0.94487. The CPE values were 1-5.0779620E-21 and 1-3.257436E-24 for length and sequence polymorphism, respectively, while the CPD values were 1-1.727007E-59 and 1-5.517015E-66, respectively. Among the 80 Y-STR loci, the HD values for length and sequence polymorphism were 0.99764282 and 0.99894195, respectively. The HMP values stood at 0.00418102 and 0.00288427, respectively, and the DC values were 0.75502742 and 0.83363803, respectively. For the 52 A-STR loci, we identified 554 and 989 distinct alleles based on length and sequence polymorphisms, respectively. For the 81 Y-STR loci, 464 and 652 unique alleles were detected at the length and sequence level, respectively. Population genetic analysis revealed that the Meizhou Hakka population has a close kinship relationship with the Asian populations THI and KOR based on length polymorphism data of A-STRs. Conversely, based on length polymorphism data of Y-STRs, the Meizhou Hakka population has the closest kinship relationship with the Henan Han population.
Discussion: Overall, the variation information of repeat region sequences significantly enhances the forensic identification efficacy of STR genetic markers, providing an essential database for forensic individual and paternity testing in this region. Additionally, the data generated by our study will serve as a vital resource for research into the genetic structure and historical origins of the Meizhou Hakka population.

引言：短串联重复序列（Short Tandem Repeats, STRs）是法医科学领域极具应用价值的遗传标记。然而，传统聚合酶链反应-毛细管电泳（PCR-CE）技术存在一定局限，而大规模平行测序（massively parallel sequencing, MPS）技术的出现为STR分析带来了新的机遇。但目前基于MPS技术开展的中国人群遗传多样性研究仍较为有限。
方法：本研究依托MGISEQ-2000测序平台，采用法医分析系统Multiplecues SetB试剂盒，获取了中国广东省梅州客家人群52个常染色体STR（A-STRs）与81个Y染色体STR（Y-STRs）的基因型数据。
结果：本研究结果表明，上述133个STR位点在梅州客家人群中具备极高的法医应用效能。统计分析显示，基于长度多态性的A-STR观测杂合度（Hobs）范围为0.61306~0.91083，期望杂合度（Hexp）范围为0.59156~0.91497；基于序列多态性的A-STR观测杂合度范围为0.61306~0.94586，期望杂合度波动范围为0.59156~0.94487。长度多态性与序列多态性的累积排除概率（CPE）分别为1-5.0779620E-21与1-3.257436E-24，累积个体识别率（CPD）分别为1-1.727007E-59与1-5.517015E-66。在80个Y-STR位点中，长度多态性与序列多态性的单倍型多样性（HD）分别为0.99764282与0.99894195，单倍型匹配概率（HMP）分别为0.00418102与0.00288427，分辨能力（DC）分别为0.75502742与0.83363803。针对52个A-STR位点，基于长度多态性与序列多态性分别鉴定出554个与989个不同等位基因；针对81个Y-STR位点，长度层面与序列层面分别检测到464个与652个独特等位基因。群体遗传学分析显示，基于A-STR长度多态性数据，梅州客家人群与亚洲人群THI、KOR亲缘关系较近；而基于Y-STR长度多态性数据，梅州客家人群与河南汉族人群亲缘关系最近。
讨论：总体而言，重复区域序列的变异信息可显著提升STR遗传标记的法医识别效能，为该区域的法医个体识别与亲权鉴定提供了关键的基础数据库。此外，本研究生成的数据将为梅州客家人群的遗传结构及历史起源研究提供重要的资源支撑。