DNA-based prediction of human phenotypic traits for the medico-legal and forensic purposes

This study aims to present the current state of knowledge on the DNA-based prediction of human externally visible characteristics of an unknown person based on the crime scene biological material left behind. This DNA sample is referred to as a “biological witness” and the procedure itself is called forensic DNA phenotyping (FDP). The analytic part of this work is based on scholarly articles published between 2015 and 2021. The electronic search of relevant references was conducted according to the PRISMA methodology in March 2021 at EBSCO Discovery Service (EDS) at the Adam Mickiewicz University library and Google Scholar. The molecular basis of FDP, DNA markers used to predict sex, age, biogeographic origin and externally visible traits such as pigmentation (skin, eye and hair colour), hair morphology, facial morphology, presence of freckles, body height, body weight (obesity), male pattern baldness and myopia were described. Furthermore, methodological difficulties resulting from the polygenic inheritance of the studied traits, as well as social and ethical problems accompanying forensic DNA phenotyping were discussed. Finally, key themes for future research related to forensic DNA phenotyping were outlined.