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.

Evaluation of a custom QIAseq targeted DNA panel with 164 ancestry informative markers sequenced with the Illumina MiSeq

Introduction of new methods requires meticulous evaluation before they can be applied to forensic genetic case work. Here, a custom QIAseq Targeted DNA panel with 164 ancestry informative markers was assessed using the MiSeq sequencing platform. Concordance, sensitivity, and the capability for analysis of mixtures were tested. The assay gave reproducible and nearly concordant results with an input of 10 and 2 ng DNA. Lower DNA input led to an increase in both locus and allele drop-outs, and a higher variation in heterozygote balance. Locus or allele drop-outs in the samples with less than 2 ng DNA input were not necessarily associated with the overall performance of a locus. Thus, the QIAseq assay will be difficult to implement in a forensic genetic setting where the sample material is often scarce and of poor quality. With equal or near equal mixture ratios, the mixture DNA profiles were easily identified by an increased number of imbalanced heterozygotes. For more skewed mixture ratios, the mixture DNA profiles were identified by an increased noise level. Lastly, individuals from Great Britain and the Middle East were investigated. The Middle Eastern individuals showed a greater affinity with South European populations compared to North European populations.

Conducting forensic and genetic examination in civil judiciary as an object of constitutional protection

The article is devoted to the study of forensic genetic examination in civil proceedings as an object of constitutional protection, due to the emergence of the concept of forensic examination in general and forensic genetic examination, entities entitled to conduct forensic examinations, analyzing the legal basis of court - genetic examination in Ukraine. Characteristics of the legal basis for recognition of paternity/mother and establishing the fact of paternity/mother are presented. The admissible and appropriate evidence bases in such cases and the place of forensic genetic examination in in the system of evidence that can be involved in the case have been clarified. The features of this examination have been studied, basis to proceed with the molecular genetic examination, the grounds for conducting a molecular genetic examination have been determined, and the issues raised before the expert carrying out the expert research have been singled out. The analysis of judicial practice of consideration of cases on recognition of paternity/maternity and the establishment of the fact of paternity/maternity which is carried out with carrying out forensic genetic examination was carried out. The article analyzes the problematic issues that arise in the process of legal regulation of forensic genetic examination and the practice of applying legislation in this area. The problems of evasion of a party from participation in forensic genetic examination, namely, non-appearance at a certain time to participate in the examination, failure to provide materials for expert research and the legal consequences of such evasion for all participants in the case. This article offers ways to solve problematic aspects of the research. The conclusions on the application by the courts of the results of forensic genetic examination during the consideration of cases on recognition of paternity/maternity, establishment of the fact of paternity/maternity were generalized and made. Forensic genetic examination is an individual identify. This type of examination allows not only to categorically exclude paternity, but also to carry out the origin of the child from both parents due to blood relationship (identification), as well as the diagnosis of hereditary diseases in the fetus in the early stages of pregnancy. Conducting such an examination is an effective mechanism of constitutional protection, because the facts established as a result of the examination form the basis of the evidence base are considered in conjunction with other evidence available in the case file.

Associations between forensic loci and neighboring gene expression levels may compromise medical privacy

A set of 20 short tandem repeats (STRs) is used by the United States criminal justice system to identify suspects, and to maintain a database of genetic profiles for individuals who have been previously convicted or arrested. Some of these STRs were identified in the 1990s, with a preference for markers in putative gene deserts to avoid forensic profiles revealing protected medical information. We revisit that assumption, investigating whether forensic genetic profiles reveal information about gene expression variation, or potential medical information. We find six significant correlations (FDR = 0.23) between the forensic STRs and the expression levels of neighboring genes in lymphoblastoid cell lines. We explore possible mechanisms for these associations, with evidence compatible with forensic STRs causing expression variation, or being in LD with a causal locus in three cases, and weaker or potentially spurious associations in the other three cases. Together, these results suggest that forensic genetic loci may reveal expression level and, perhaps, medical information.

A DNA-based method for distinction of fly artifacts from human bloodstains

Fly artifacts resulting from insect activity could act as confounding factors on a crime scene and interfere with bloodstain pattern analysis interpretation. Several techniques have been proposed to distinguish fly artifacts from human bloodstains based on morphological approach and immunological assay, but a DNA-based method has not been developed so far. Even if in forensic genetic investigations the detection of human DNA is generally the primary goal, fly artifacts can provide useful information on the dynamics of crime events. The present study provides a molecular method to detect fly DNA from artifacts deposited by Calliphora vomitoria after feeding on human blood through the analysis of the mitochondrial cytochrome oxidase gene subunit I (COI). Fly artifacts originated from digestive process and of different morphology spanning from red and brownish/light brown, circular and elliptical stains to artifacts with sperm-like tail or a tear-shaped body were collected. The COI amplification was successfully obtained in 94% of fly artifact samples. The method showed high sensitivity and reproducibility, and no human DNA contamination was observed, offering specificity for use in confirmatory test. This molecular approach permits the distinction of fly artifacts from genuine bloodstains and the identification of fly’s species through the COI region sequencing by protocols usually applied in forensic genetic laboratories.

Interpretation of DNA data within the context of UK forensic science — investigation

This article is the second part of a review of the interpretation of DNA data in forensic science. The first part describes the evaluation of autosomal profile for criminal trials where an evidential weight is assigned to the profile of a person of interest (POI) and a crime-scene profile. This part describes the state of the art and future advances in the interpretation of forensic DNA data for providing intelligence information during an investigation. Forensic DNA is crucial in the investigative phase of an undetected crime where a POI needs to be identified. A sample taken from a crime scene is profiled using a range of forensic DNA tests. This review covers investigation using autosomal profiles including searching national and international crime and reference DNA databases. Other investigative methodologies described are kinship analysis; familial searching; Y chromosome (Y-STR) and mitochondrial (mtDNA) profiles; appearance prediction and geographic ancestry; forensic genetic genealogy; and body identification. For completeness, the evaluation of Y-STRs, mtDNA and kinship analysis are briefly described. Taken together, parts I and II, cover the range of interpretation of DNA data in a forensic context.