Statistical and Computational Methodology for the Analysis of Forensic DNA Mixtures with Artefacts

Thesis

This thesis proposes and discusses a statistical model for interpreting forensic DNA mixtures. We develop methods for estimation of model parameters and assessing the uncertainty of the estimated quantities. Further, we discuss how to interpret the mixture in terms of predicting the set of contributors.

We emphasise the importance of challenging any interpretation of a particular mixture, and for this purpose we develop a set of diagnostic tools that can be used in assessing the adequacy of the model to the data at hand as well as in a systematic validation of the model on experimental data.

An important feature of this work is that all methodology is developed entirely within the framework of the adopted model, ensuring a transparent and consistent analysis.

To overcome the challenge that lies in handling the large state space for DNA profiles, we propose a representation of a genotype that exhibits a Markov structure. Further, we develop methods for efficient and exact computation in a Bayesian network. An implementation of the model and methodology is available through the R package DNAmixtures.

Authors: Graversen, T

• Publication date: 2014
• DOI: 10.5287/ora-ae7w8v6mp
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: Oxford University, UK
• Language: English
• Keywords: Bayesian network; gamma distribution; probabilistic expert system; probability propagation; statistics; DNA mixture analysis; forensic genetics
• Subjects: Mathematical genetics and bioinformatics (statistics); Statistics (see also social sciences); Computationally-intensive statistics; Statistics (social sciences); Computing