de la Puente M, Phillips C, Fondevila M, Gelabert-Besada M, Carracedo Á, Lareu M V
Forensic Genetics Unit, Institute of Forensic Sciences, University of Santiago de Compostela, Spain.
Forensic Genetics Unit, Institute of Forensic Sciences, University of Santiago de Compostela, Spain.
Forensic Sci Int Genet. 2017 Jul;29:154-164. doi: 10.1016/j.fsigen.2017.04.007. Epub 2017 Apr 15.
Pentameric-repeat short tandem repeats (STRs), consisting of loci with repeat units of five base-pairs, have the advantage of reduced stutter products compared to their tetrameric-repeat STR counterparts. This characteristic potentially helps the interpretation of mixed DNA profiles when minor component alleles may coincide with stutter peaks from the major components. To develop a simple but informative forensic multiplex with the capability to aid mixture interpretation, we designed an 11-plex assay of nine pentameric STRs new to forensic analysis plus two male- specific markers: DYS391 and the Y-Indel rs2032678 used in GlobalFiler™ (Life Technologies). East Asian-specific variation in the recently adopted Y-Indel rs2032678 is reported in this study for the first time in its forensic use as a sex marker. We estimated the levels of variation observed in the nine pentameric STRs in three of the major population groups sampled in the HGDP-CEPH human genome diversity panel: African, European and East Asian (combining individual populations as their sample sizes were too small for STR allele frequency estimations); and we include genotype data from a population sample of Northwest Spain. From this data, forensic informativeness metrics were estimated when applying the nine novel STRs in identification or kinship analyses. The assay was assessed for forensic sensitivity and ability to successfully genotype highly degraded DNA. In the profiles from the 11-plex assay we observed an average 2.15% stutter ratio in all the pentameric loci compared to 7.32% across equivalently-sized tetrameric STRs in the Promega Powerplex ESX-17 kit.
五聚体重复短串联重复序列（STR）由具有五个碱基对重复单元的基因座组成，与四聚体重复STR相比，其优势在于减少了拖尾产物。当次要成分等位基因可能与主要成分的拖尾峰重合时，这一特性可能有助于混合DNA图谱的解读。为了开发一种简单但信息丰富的法医多重检测方法，以协助混合样本解读，我们设计了一种11重检测方法，包含9个法医分析中首次使用的五聚体STR以及两个男性特异性标记：DYS391和用于GlobalFiler™（赛默飞世尔科技公司）的Y-插入缺失rs2032678。本研究首次报道了最近采用的Y-插入缺失rs2032678在东亚人群中的特异性变异，该变异在法医用作性别标记时具有重要意义。我们估计了人类基因组多样性计划（HGDP-CEPH）样本中三个主要人群组（非洲、欧洲和东亚，由于个体样本量过小无法进行STR等位基因频率估计，故将各个人群合并）中9个五聚体STR的变异水平；并且我们纳入了来自西班牙西北部人群样本的基因型数据。根据这些数据，评估了应用这9个新型STR进行身份鉴定或亲缘关系分析时的法医信息学指标。对该检测方法的法医灵敏度以及对高度降解DNA成功进行基因分型的能力进行了评估。在11重检测方法的图谱中，我们观察到所有五聚体位点的平均拖尾率为2.15%，而Promega Powerplex ESX-17试剂盒中同等大小的四聚体STR的平均拖尾率为7.32%。
