Statistical aspects of forensic genetics:Models for qualitative and quantitative STR data

This PhD thesis deals with statistical models intended for forensic genetics, which is the part of forensic medicine concerned with analysis of DNA evidence from criminal cases together with calculation of alleged paternity and affinity in family reunification cases. The main focus of the thesis is on crime cases as these differ from the other types of cases since the biological material often is used for person identification contrary to affinity. Common to all cases, however, is that the DNA is used as evidence in order to assess the prob-ability of observing the biological material given different hypotheses. Most countries use com-mercially manufactured DNA kits for typing a person’s DNA profile. Using these kits the DNA profile is constituted by the state of 10-15 DNA loci which has a large variation from person to person in the population. Thus, only a small fraction of the genome is typed, but due to the large variability, it is possible to identify individuals with very high probability. These probabil-ities are used when calculating the weight of evidence, which in some cases corresponds to the likelihood of observing a given suspect’s DNA profile in the population. By assessing the probability of the DNA evidence under competing hypotheses the biologica

Review of the Forensic Applicability of Biostatistical Methods for Inferring Ancestry from Autosomal Genetic Markers

The inference of ancestry has become a part of the services many forensic genetic laboratories provide. Interest in ancestry may be to provide investigative leads or identify the region of origin in cases of unidentified missing persons. There exist many biostatistical methods developed for the study of population structure in the area of population genetics. However, the challenges and questions are slightly different in the context of forensic genetics, where the origin of a specific sample is of interest compared to the understanding of population histories and genealogies. In this paper, the methodologies for modelling population admixture and inferring ancestral populations are reviewed with a focus on their strengths and weaknesses in relation to ancestry inference in the forensic context