【摘要】 目的 评估52个常染色体短串联重复（A-STR）序列标记的长度与序列多态性分型在法医学实践中1～3级亲缘关系的鉴识效能。方法 基于Set B扩增体系包含的52个A-STR基因座长度与序列多态性等位基因频率数据，使用Easykin软件模拟计算1级、2级和3级亲缘关系在两种假设下（H1：争议的两个体间存在某种亲缘关系；H2：争议的两个体间为无关个体）的似然比（likelihood ratio,LR）值分布，评估在判定H1和H2为真阈值（t值）下的亲缘鉴识效能参数；同时，对1～3级亲缘关系各85对样本进行该52个A-STR基因座测序分型，评估该52个A-STR检测体系在真实1～3级亲缘关系鉴定中的实用性。结果 当t设定为10时，基于长度多态性的模拟数据，1级、2级、3级亲缘关系鉴定的系统效能分别为0.99、0.93、0.52以上，而基于序列多态性的模拟数据，系统效能分别为0.99、0.96、0.63以上；当t设定为100时，基于长度多态性的模拟数据，1级、2级、3级亲缘关系鉴定的系统效能分别为0.99、0.81、0.15以上，而基于序列多态性的模拟数据，系统效能为0.99、0.90、0.28以上。对于1级亲缘关系内亲子和全同胞的鉴识，当t设定为100时，基于长度多态性模拟数据，系统效能≥0.98，基于序列多态性模拟数据，则系统效能≥0.99。对于真实样本的亲缘关系对，当t设定为100时，基于序列多态性分型结果，100%的1级亲缘关系对和98%的2级亲缘关系对可以正确识别。结论 基于52个A-STR遗传标记的长度和序列多态性分型，可以鉴识法医学中常见的1级和2级亲缘关系，尤其是1级亲缘关系内的亲子与全同胞关系；与长度多态性相比，序列多态性分型可以提升亲缘鉴识效能。更多还原

【Abstract】 Objective To evaluate the forensic efficacy of 52 autosomal short tandem repeat(A-STR) markers for identifying first-to third-degree kinship through length and sequence polymorphism genotyping. Methods Based on the allele frequencies of length and sequence polymorphisms for 52 A-STR loci within the Set B amplification system, likelihood ratio(LR) distributions for first-, second-, and third-degree relationships were simulated using Easykin software under two hypotheses(H1: the two individuals share a specific biological relationship; H2: the two individuals are unrelated). Performance parameters for kinship identification were assessed at various decision thresholds(t). Additionally, genotyping was performed on 85 pairs of confirmed samples for each kinship degree to evaluate the practicality of the 52 A-STR system in real-world forensic kinship testing. Results With a threshold t = 10, the systematic power for first-, second-, and third-degree kinship identification based on length polymorphism simulation was ≥ 0.99, ≥ 0.93, and ≥ 0.52, respectively; whereas for sequence polymorphism, the values increased to ≥ 0.99, ≥ 0.96, and ≥ 0.63. When t was increased to 100, the systematic power based on length polymorphism was ≥ 0.99, ≥ 0.81, and ≥ 0.15, while sequence polymorphism yielded ≥ 0.99, ≥ 0.90, and ≥ 0.28. For first-degree relationships(parent-child and full-sibling pairs) at t =100, length polymorphism simulation achieved a systematic power of ≥ 0.98, compared to ≥ 0.99 for sequence polymorphism. Validation using real samples demonstrated that at t = 100, 100% of first-degree and 98% of second-degree kinship pairs were correctly identified using sequence polymorphism data. Conclusion Genotyping of 52 A-STR markers based on both length and sequence polymorphisms provides robust identification of first-and second-degree relationships, particularly parent-child and full-sibling pairs. Notably sequence polymorphism genotyping significantly enhances kinship identification power compared to traditional length polymorphism.更多还原