A novel set of DIP-STR markers for improved analysis of challenging DNA mixtures
A novel set of DIP-STR markers for improved analysis of challenging DNA mixtures
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DOI：
10.1016/j.fsigen.2015.07.012
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发表时间：
2015-11-01
影响因子：
3.1
通讯作者：
Hall, Diana
中科院分区：
文献类型：
--
作者：
Oldoni, Fabio;Castella, Vincent;Hall, Diana
目前可用的分子生物学工具使法医科学家能够对在犯罪现场发现的大量样本（包括数量和质量有限的样本）的DNA证据进行定性，并实现高度个性化。然而，标准法医标记物在应用于混合DNA样品时提供有限的结果或没有结果，其中贡献者以非常不同的比例存在（不平衡的DNA混合物）。为此，我们最近提出了一种创新类型的遗传标记，命名为DIP-STR，它依赖于配对缺失/插入多态性（DIP）与标准短串联重复序列（STR）。为了给普通法医学实验室提供一种新的实用分析工具，本文介绍了根据法医学技术标准筛选出的第一组10个DIP-STR标记。新的DIP-STR区域很短（在146和271 bp之间），仅包括高度多态性的三核苷酸、四核苷酸和五核苷酸串联重复序列，并且位于不同的染色体或染色体臂上以提供统计学独立的结果。当与1000倍过量的主要DNA混合时，这种新的DIP-STR组可以靶向扩增0.03 - 0.1 ng的DNA。DIP-STR相对等位基因频率是根据对103名瑞士人的调查估计的。最后，本研究提供了一个估计的信息等位基因的发生和相应的随机匹配概率的计算检测到的次要DIP-STR基因型评估在10,506成对的概念混合物。(C)2015爱思唯尔爱尔兰有限公司版权所有。
Currently available molecular biology tools allow forensic scientists to characterize DNA evidence found at crime scenes for a large variety of samples, including those of limited quantity and quality, and achieve high levels of individualization. Yet, standard forensic markers provide limited or no results when applied to mixed DNA samples where the contributors are present in very different proportions (unbalanced DNA mixtures). This becomes an issue mostly for the analysis of trace samples collected on the victim or from touched objects.To this end, we recently proposed an innovative type of genetic marker, named DIP-STR that relies on pairing deletion/insertion polymorphisms (DIP) with standard short tandem repeats (STR). This novel compound marker allows detection of the minor DNA contributor in a DNA mixture of any gender and cellular origin with unprecedented resolution (beyond a DNA ratio of 1: 1000).To provide a novel analytical tool useful in practice to common forensic laboratories, this article describes the first set of 10 DIP-STR markers selected according to forensic technical standards. The novel DIP-STR regions are short (between 146 and 271 bp), include only highly polymorphic tri-, tetra-and pentanucleotide tandem repeats and are located on different chromosomes or chromosomal arms to provide statistically independent results. This novel set of DIP-STR can target the amplification of 0.03-0.1 ng of DNA when mixed with a 1000-fold excess of major DNA. DIP-STR relative allele frequencies are estimated based on a survey of 103 Swiss individuals. Finally, this study provides an estimate of the occurrence of informative alleles and a calculation of the corresponding random match probability of the detected minor DIP-STR genotype assessed across 10,506 pairwise conceptual mixtures. (C) 2015 Elsevier Ireland Ltd. All rights reserved.