Bright Jo-Anne, Andersen Mikkel Meyer, Taylor Duncan, Kelly Hannah, Kruijver Maarten, Buckleton John
Institute of Environmental Science and Research Limited, Auckland, New Zealand.
Department of Mathematical Sciences, Aalborg University, Aalborg, Denmark.
J Forensic Sci. 2025 Jan;70(1):271-275. doi: 10.1111/1556-4029.15669. Epub 2024 Nov 17.
The Y chromosomal haplotype is expected to be identical (or close to, depending on the mutation rate) among a male and many of his paternal relatives. This means that often the same evidential value for the DNA evidence is obtained, whether the true donor or one of his close paternal relatives is compared to a crime sample. Commentators (see for example the UK Forensic Science Regulator or Amorim) have suggested to change the proposition pair to compare the probability of the evidence if the Person of Interest (POI) or one of his close paternal relatives left the DNA to the probability of the evidence if an unrelated male from the population left the DNA. We argue that this is problematic because there is no clear definition of close paternal relatives and truly unrelated males do not exist. Instead, we take a starting point in the traditional proposition pair "The source of the male DNA is the POI" versus "The source of the male DNA is not the POI" and make the latter one operational by suggesting that it is formulated as "The source of the male DNA is a random man from the population". The issue of matching males in the POI's lineage is then addressed either in a comment in the statement or directly through a probability model.
在男性及其许多父系亲属中，Y染色体单倍型预计是相同的（或接近相同，这取决于突变率）。这意味着，无论将真正的DNA提供者还是其近亲父系亲属之一与犯罪样本进行比对，通常都会获得相同的DNA证据价值。评论者（例如英国法医学监管机构或阿莫林）建议更改命题对，即比较如果犯罪嫌疑人（POI）或其近亲父系亲属之一留下了DNA，证据出现的概率与如果人群中一个无关男性留下了DNA，证据出现的概率。我们认为这存在问题，因为近亲父系亲属没有明确的定义，而且真正无关的男性并不存在。相反，我们以传统的命题对“男性DNA的来源是犯罪嫌疑人”与“男性DNA的来源不是犯罪嫌疑人”为出发点，并通过建议将后者表述为“男性DNA的来源是人群中的一个随机男性”来使其具有可操作性。然后，要么在陈述中的注释里，要么直接通过概率模型来解决犯罪嫌疑人谱系中男性匹配的问题。
