Hwa Hsiao-Lin, Wu Ming-Yih, Lee James Chun-I, Yin Hsiang-I, Hsu Pi-Mei, Li Shwu-Fang, Hwu Wuh-Liang, Su Chih-Wen
Department and Graduate Institute of Forensic Medicine, College of Medicine, National Taiwan University, No. 1, Sec. 1, Jen Ai Rd., Taipei 100, Taiwan; Department of Obstetrics and Gynecology, National Taiwan University Hospital, No. 7 Chung Shan S. Rd., Taipei 100, Taiwan; Department of Medical Genetics, National Taiwan University Hospital, No. 7 Chung Shan S. Rd., Taipei 100, Taiwan.
Department of Obstetrics and Gynecology, National Taiwan University Hospital, No. 7 Chung Shan S. Rd., Taipei 100, Taiwan.
Leg Med (Tokyo). 2020 Feb;42:101631. doi: 10.1016/j.legalmed.2019.101631. Epub 2019 Oct 25.
Identification of the minor contributor in DNA mixture of close relatives remains a dilemma in forensic genetics. Massively parallel sequencing (MPS) can analyze multiple short tandem repeats (STRs) and single nucleotide polymorphism (SNPs) concurrently and detect non-overlapping alleles of the minor contributors in DNA mixtures. A commercial kit for MPS of 59 identity informative STRs (iiSTRs) and 94 autosomal identity-informative SNPs (iiSNPs) was used to analyzed 34 nondegraded and 33 highly degraded two-person artificial DNA mixtures of close relatives with various minor to major ratios (1:9, 1:19, 1:29, 1:39, 1:79, 1:99). EuroForMix software was used to determine the minor contributors in the mixtures based on the likelihood ratios calculated from the MPS data, and relMix software was used to perform kinship analysis of the contributors. The STRs and SNPs of the 34 nondegraded and 33 degraded DNA mixtures were genotyped using MPS. Using EuroForMix based on the genotypes of autosomal iiSTRs and autosomal iiSNPs, 82.4% (28/34) and 54.5% (18/33) of minor donors could be accurately assigned for the nondegraded and degraded DNA mixtures, respectively. The relMix software correctly inferred the relationship between contributors in 97.1% (33/34) of nondegraded mixtures and in 97.0% (32/33) of degraded mixtures. In conclusion, combined EuroForMix and MPS data of STRs and SNPs can assist in the assignment of minor donors in nondegraded DNA mixtures of close relatives, and relMix can be used to infer relationship among contributors.
在法医遗传学中，识别近亲DNA混合样本中的次要贡献者仍然是一个难题。大规模平行测序（MPS）能够同时分析多个短串联重复序列（STR）和单核苷酸多态性（SNP），并检测DNA混合样本中次要贡献者的非重叠等位基因。使用一种用于59个身份信息STR（iiSTR）和94个常染色体身份信息SNP（iiSNP）的MPS商业试剂盒，分析了34个未降解和33个高度降解的两人近亲人工DNA混合样本，其具有各种次要与主要比例（1:9、1:19、1:29、1:39、1:79、1:99）。基于从MPS数据计算出的似然比，使用EuroForMix软件确定混合样本中的次要贡献者，并使用relMix软件对贡献者进行亲缘关系分析。使用MPS对34个未降解和33个降解DNA混合样本的STR和SNP进行基因分型。基于常染色体iiSTR和常染色体iiSNP的基因型，使用EuroForMix，分别有82.4%（28/34）和54.5%（18/33）的次要贡献者能够被准确分配到未降解和降解的DNA混合样本中。relMix软件在97.1%（33/34）的未降解混合样本和97.0%（32/33）的降解混合样本中正确推断出贡献者之间的关系。总之，结合EuroForMix以及STR和SNP的MPS数据可以辅助识别近亲未降解DNA混合样本中的次要贡献者，并且relMix可用于推断贡献者之间的关系。
