Development, Validation and Implementation of Forensic DNA Phenotyping Tools in the VISAGE Project

The prediction of externally visible characteristics from DNA for law enforcement purposes has become one of the major avenues of forensic genetic research in the past years. The concept is known under the term Forensic DNA Phenotyping (FDP) and currently includes the DNA-based prediction of appearance, bio-geographic ancestry and age (AAA) from a DNA (crime scene) sample of an unknown person. The aim of FDP is to provide new investigative leads in forensic cases that lack known suspects or to support the identification of unknown human remains. The EU-funded VISAGE (VISible Attributes through GEnomics) Project (www.visage-h2020.eu/) pursues research in FDP in a multi-disciplinary forum including 13 institutional partners from eight European countries representing academic (genetics/genomics, statistics, social science) and governmental (central national police or justice) institutions. The scope of the VISAGE Project involves the development, validation and implementation of DNA markers, analysis tools and software tools for DNA-based AAA-prediction from forensically relevant samples. The laboratory tools are strictly based on Massively Parallel Sequencing (MPS) technologies to allow multiplexing of hundreds of DNA markers, to streamline the laboratory process, and to harmonize methods and results for reproducible and sensitive data generation for both SNP-based (combined appearance and ancestry) and methylation-based (age) analyses. In order to arrive at an integrative statistical framework for AAA prediction, we investigated the suitability of spatial trait prevalence priors, trait correlations and machine learning classification methods for improving prediction accuracies. We implemented prediction models for various appearance traits, continental and subcontinental ancestry and age from different tissue sources in a user-friendly software that automatically generates trait probabilities from the produced MPS data including automated report generation for further use by the forensic DNA expert. VISAGE puts strong emphasis on considerations of ethical, societal, and legal dimensions of FDP and applying a privacy-by-design strategy. The project outcomes are subject to various dissemination activities with the aim to inform and educate different stakeholders in the law enforcement process.