Laboratory of Forensic DNA, the Judicial Authentication Center, Southwest Medical University, Luzhou, 646000, Sichuan, China.
Key Laboratory of Epigenetics and Oncology, the Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, 646000, Sichuan, China.
Int J Legal Med. 2021 Sep;135(5):1737-1741. doi: 10.1007/s00414-021-02592-1. Epub 2021 Apr 12.
Y-chromosome short tandem repeat (Y-STR) markers have been widely used in forensic applications and usually show monoallelic or diallelic genotypic patterns at certain double-copied loci. In this study, we have found 13 samples among 703 males with multi-alleles at the DYS385ab locus, including one with five mutant alleles, nine with four, and three with three. The frequency of abnormal DYS385ab genotypes was 1.85% (13/703), which is very high in the Han Chinese population. The percentage of samples with diallelic patterns at DYS385ab was higher than that of monoallelic patterns (80.23% vs. 17.92%). Additionally, the percentage of samples with tetra-allelic patterns at DYS385ab was higher than that of tri-allelic patterns (1.28% vs. 0.43%), suggesting that there are possibly two copies with duplicated events happening frequently on the Y chromosome. Interestingly, the peak height of allele 13 was two to three-folds higher than that of other alleles. The allele 18 peak height was also two-fold higher than others, which could potentially be explained by a duplication event mechanism. We also found that tri-allelic genotypes for alleles 13, 17, and 20, tetra-allelic genotypes for alleles 13, 14, 19, and 20, and tetra-allelic genotypes for alleles 12, 13, 19 and 21 were more common than others. Furthermore, all 13 samples had multi-alleles containing allele 13, implying a founder effect in this particular Chinese-specific ethnic group. Taken together, this study provides new information for this population and will be useful for paternal lineage identification, kinship analysis, and family relationship reconstruction using Y-STR forensic DNA analysis methods.
Y 染色体短串联重复序列（Y-STR）标记已广泛应用于法医学领域，通常在某些重复的基因座上表现为单等位基因或双等位基因的基因型模式。在这项研究中，我们在 703 名男性中发现了 13 个样本在 DYS385ab 基因座上具有多等位基因，其中一个样本具有 5 个突变等位基因，9 个样本具有 4 个，3 个样本具有 3 个。异常 DYS385ab 基因型的频率为 1.85%（13/703），在中国汉族人群中非常高。DYS385ab 具有双等位基因模式的样本比例高于单等位基因模式（80.23%比 17.92%）。此外，DYS385ab 具有四等位基因模式的样本比例高于三等位基因模式（1.28%比 0.43%），这表明 Y 染色体上可能有两个拷贝发生了频繁的重复事件。有趣的是，等位基因 13 的峰高是其他等位基因的两到三倍。等位基因 18 的峰高也是其他等位基因的两倍，这可能是由重复事件机制导致的。我们还发现，等位基因 13、17 和 20 的三等位基因基因型、等位基因 13、14、19 和 20 的四等位基因基因型以及等位基因 12、13、19 和 21 的四等位基因基因型比其他基因型更为常见。此外，所有 13 个样本均含有多等位基因 13，这表明在中国特定的少数民族群体中存在一个起源效应。综上所述，本研究为该人群提供了新的信息，对于使用 Y-STR 法医 DNA 分析方法进行父系鉴定、亲缘关系分析和家庭关系重建将非常有用。
