Quo vadis, BGA? A collaborative EDNAP exercise on the challenges and progress in forensic biogeographical ancestry inference.
The study reveals significant challenges in interpreting forensic DNA results for ancestry and visible characteristics, emphasizing the need for careful consideration in forensic investigations.
Where it sits
this study against the rest of the slu-pp-332 (exercise mimetic) corpusSummary and findings
This study evaluated the reporting of externally visible characteristics (EVC) and biogeographic ancestry (BGA) data among international forensic laboratories using DNA from nine individuals with self-reported ancestry. Various forensic panels differing in ancestry-informative markers were utilized. The study aimed to identify challenges in interpreting EVC and BGA results.
Abstract
There is a broad consensus that forensic tests for the prediction of externally visible characteristics (EVC) and analysis of biogeographic ancestry (BGA) of an individual are technically reliable. However, interpretation of the results and population-specific genotype distribution patterns remains challenging. EVC and BGA analyses provide valuable information for population genetics studies and as investigative leads for criminal cases, as well as for historical and contemporary identification tests. However, inaccurate or incorrect predictions, for example, from subjective bias in the interpretations made, have the potential to misdirect police investigations. The legal situation regarding EVC and BGA testing varies by country: ranging from countries where it is explicitly prohibited, to those without specific regulations on biogeographic ancestry prediction, and others that have already enacted laws governing its use. The reluctance to utilize these analyses is not only due to legal restrictions and data protection concerns, but also to initial limited sets of sufficiently comprehensive forensic DNA assays. Forensic BGA marker panels typically contain up to ∼300 SNPs. This relatively small number of genetic markers, along with limited reference population data, complicates the interpretation of results from donors of unknown origin. This paper presents the results of a collaborative EDNAP study, which, for the first time, evaluated the approach to reporting EVC and BGA data between international laboratories. For the study, DNA from nine individuals with self-reported ancestry was collected and analysed using various forensic panels differing in the number and composition of ancestry-informative markers genotyped, comprising: the Precision ID mtDNA Whole Genome Panel, the VISAGE Basic Tool and the VISAGE Enhanced Tool for Appearance and Ancestry Prediction, and the Ion AmpliSeq™ PhenoTrivium Panel. To ensure full data protection, all SNP genotypes and uniparental marker haplotypes obtained were not shared with third parties. Instead, the genetic data were analysed using a range of commonly used population analysis software packages. These analysis outcomes were then distributed to twelve European forensic laboratories (both academic and law enforcement institutions), who were asked to prepare reports based on their interpretation of the phenotypes and ancestry they inferred from the analysis data. A questionnaire sent alongside the genetic information, aimed to evaluate which difficulties were encountered by the participants in processing the BGA analysis data they were given.
Background
This paper addresses the challenges in interpreting forensic tests for predicting externally visible characteristics and biogeographic ancestry. Previous research has established that such tests are technically reliable, but issues remain regarding the interpretation of results and population-specific genotype distributions. Understanding these challenges is crucial for improving forensic practices and ensuring accurate investigations.
Methods
The study involved a collaborative effort where DNA from nine individuals with self-reported ancestry was collected. Various forensic panels were used, including the Precision ID mtDNA Whole Genome Panel and the VISAGE Basic and Enhanced Tools. The analysis was conducted using population analysis software, and results were shared with twelve European forensic laboratories for interpretation.
Results
Not reported in abstract.
Interpretation
The findings highlight the complexities involved in interpreting EVC and BGA data, particularly with a limited number of genetic markers and reference population data. While the study provides insights into the collaborative efforts of forensic laboratories, the small sample size and potential biases in self-reported ancestry may limit the applicability of the results. Practitioners should be cautious in relying solely on these analyses for investigative purposes.
Key findings
- DNA from nine individuals with self-reported ancestry was collected and analysed.
- Forensic BGA marker panels typically contain up to ∼300 SNPs.
- Analysis outcomes were distributed to twelve European forensic laboratories for interpretation.
Limitations
- small sample size of n=9
- limited reference population data
- potential subjective bias in interpretations
- no statistical analysis reported