Current state of extended DNA analysis: Scientific plea for a legal regulation on the prediction of the biogeographical origin of unknown trace donors

Abstract

Since the revision of § 81e of the German Code of Criminal Procedure (StPO) in 2019, forensic molecular genetic methods for predicting eye, hair and skin color as well as for estimating age, have been used to support police investigations of unknown trace donors; however, the prediction models currently used in Germany and Europe are not or insufficiently specific for individuals of non-European origin. Both age-dependent DNA methylation, which is used to estimate age and the physical appearance of individuals vary between different geographical regions. Consequently, not considering a person’s origin inevitably limits the accuracy of these predictions. This carries the risk of generating incorrect results which, in the worst case, could hinder rather than help criminal investigations. To ensure that predictions about the appearance and age of an unknown trace donor are both precise and reliable, their biogeographical origin should be taken into account. Genetic ancestry analysis is the suitable method to obtain information about the origin of an unknown individual from biological material. The results of this analysis alone provide valuable investigative leads and, as a cofactor, can further improve the accuracy of appearance prediction and age estimation.