Forensic DNA Phenotyping: a review on SNP panels, genotyping techniques, and prediction models

In the past few years, forensic DNA phenotyping (FDP) has attracted a strong interest in the forensic research. Among the increasing publications, many have focused on testing the available panels to infer biogeographical ancestry (BGA) on less represented populations and understanding the genetic mechanisms underlying externally visible characteristics (EVC). However, there are currently no publications that gather all the existing panels limited to FDP and discuss the main technical limitations of the technique. In this review, we performed a bibliographic search in Scopus database of FDP-related literature, which resulted in a total of 48, 43 and 15 panels for BGA, EVC and both BGA and EVC inference, respectively. Here we provide a list of commercial and non-commercial FDP panels and the FDP limitations regarding the lack of harmonization in terms of terminology (i.e., categorization and measurement of traits) and reporting, the lack of genetic knowledge and environment influence to select markers and develop panels, and the debate surrounding the selection of genotyping technologies and prediction models and algorithms. In conclusion, this review aims to be an updated guide and to present an overview of the current FDP-related literature.