Criteria for selecting microhaplotypes: mixture detection and deconvolution.
Criteria for selecting microhaplotypes: mixture detection and deconvolution.
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DOI：
10.1186/s13323-014-0018-3
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发表时间：
2015
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通讯作者：
Speed WC
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作者：
Kidd KK;Speed WC
DNA测序很可能在不久的将来成为法医学中的标准分型方法。我们将微单倍型定义为具有两个或更多个单核苷酸多态性（SNP）的基因座，所述单核苷酸多态性（SNP）发生在DNA的短片段内（例如，200 bp），其可以被单个序列运行覆盖并共同限定多等位基因基因座。微单倍型可以为许多法医问题提供高度信息，包括检测DNA样品中两种或多种来源的混合物，这是法医实践中的常见问题。当所有等位基因的频率相等时，在混合物中检测到三个或更多等位基因的概率最大。在一个基因座上的等位基因的有效数量的经典群体遗传学概念，称为Ae，将在一个基因座上的不等等位基因频率转换成一个值，该值相当于一些数量的同等频率的等位基因，允许微单倍型基因座进行排名。定性检测混合物的能力的预期给出了不同的整数值的Ae，和检测混合物的基础上测试多种microsiloxare的累积概率显示超过95%，少至5个位点的平均Ae值甚至略大于3.0。Ae值> 3的微单倍型在普通法医学实践中非常有用。基于我们的研究，3-SNP微单倍型有时会满足该标准，但4-SNP微单倍型甚至可以超过该标准并且具有> 4的值。本文的在线版本（doi：10.1186/s13323 - 014 - 0018 - 3）包含补充材料，可供授权用户使用。
DNA sequencing is likely to become a standard typing method in forensics in the near future. We define a microhaplotype to be a locus with two or more single nucleotide polymorphisms (SNPs) that occur within a short segment of DNA (e.g., 200 bp) that can be covered by a single sequence run and collectively define a multiallelic locus. Microhaplotypes can be highly informative for many forensic questions, including detection of mixtures of two or more sources in a DNA sample, a common problem in forensic practice. When all alleles are equally frequent, the probability of detecting three or more alleles in a mixture is at maximum. The classical population genetics concept of effective number of alleles at a locus, termed Ae, converts the unequal allele frequencies at a locus into a value that is equivalent to some number of equally frequent alleles, allowing microhaplotype loci to be ranked. The expectations for the ability to qualitatively detect mixtures are given for different integer values of Ae, and the cumulative probabilities of detecting mixtures based on testing multiple microhaps are shown to exceed 95% with as few as five loci with average Ae values of even slightly greater than 3.0. Microhaplotypes with Ae values of >3 will be exceedingly useful in ordinary forensic practice. Based on our studies, 3-SNP microhaplotypes will sometimes meet this criterion, but 4-SNP microhaplotypes can even exceed this criterion and have values >4. The online version of this article (doi:10.1186/s13323-014-0018-3) contains supplementary material, which is available to authorized users.