Application of X-STRs for Forensic Identification in Mixed DNA Profile: A Case Report

Abstract

The analysis of autosomal polymorphism (STR) or Y chromosome polymorphisms (Y-STR) are usually used for the study and deconvolution of mixed DNA profiles in forensic genetics, accompanying data interpretation with biostatistical evaluations (e.g. RMP, RMNE, LR). Sometimes, however, some mixed DNA profiles are so complex that the autosomal and Y markers do not allow a correct discrimination and identification. In this work is reported a robbery case in which the analysis of the polymorphic markers of the X chromosome was applied to the mixed profiles obtained from the traces, thus falling outside the classic relationship use of the X-STRs. The aim of the authors is, in fact, to encourage the classic use of X-STRs not only in parental relationships, but also in purely forensic cases for interpreting complex mixed DNA profiles. Their application in case resolution could be more decisive than STR/Y-STR.