Bill Martin, Gill Peter, Curran James, Clayton Tim, Pinchin Richard, Healy Marcus, Buckleton John
The Forensic Science Service, Trident Court, Solihull Parkway, Birmingham Business Park, Solihull B377YN, UK.
Forensic Sci Int. 2005 Mar 10;148(2-3):181-9. doi: 10.1016/j.forsciint.2004.06.037.
Several years ago, a theory to interpret mixed DNA profiles was proposed that included a consideration of peak area using the method of least squares. This method of mixture interpretation has not been widely adopted because of the complexity of the associated calculations. Most reporting officers (RO) employ an experience and judgement based approach to the interpretation of mixed DNA profiles. Here we present an approach that has formalised the thinking behind this experience and judgement. This has been written into a computer program package called PENDULUM. The program uses a least squares method to estimate the pre-amplification mixture proportion for two potential contributors. It then calculates the heterozygous balance for all of the potential sets of genotypes. A list of "possible" genotypes is generated using a set of heuristic rules. External to the programme the candidate genotypes may then be used to formulate likelihood ratios (LR) that are based on alternative casework propositions. The system does not represent a black box approach; rather it has been integrated into the method currently used by the reporting officers at the Forensic Science Service (FSS). The time saved in automating routine calculations associated with mixtures analysis is significant. In addition, the computer program assists in unifying reporting processes, thereby improving the consistency of reporting.
几年前，有人提出了一种解释混合DNA图谱的理论，该理论包括使用最小二乘法来考虑峰面积。由于相关计算的复杂性，这种混合图谱解释方法尚未被广泛采用。大多数报告官员（RO）采用基于经验和判断的方法来解释混合DNA图谱。在此，我们提出一种方法，该方法已将这种经验和判断背后的思路形式化。这已被编写成一个名为PENDULUM的计算机程序包。该程序使用最小二乘法来估计两个潜在贡献者的扩增前混合比例。然后，它计算所有潜在基因型组合的杂合平衡。使用一组启发式规则生成“可能的”基因型列表。在程序外部，候选基因型可用于制定基于替代案件假设的似然比（LR）。该系统并不代表一种黑箱方法；相反，它已被整合到法医科学服务局（FSS）报告官员目前使用的方法中。在自动化与混合物分析相关的常规计算方面节省的时间是可观的。此外，该计算机程序有助于统一报告流程，从而提高报告的一致性。
