Forensic molecular biomarkers for mixture analysis

The deconvolution of DNA mixtures has gathered the attention of forensic DNA scientists for over two decades. To enhance mixture deconvolution capabilities, a new generation of sensitive DNA-typing approaches has been recently proposed. In this review, we describe novel, forensically relevant multi-SNP loci (i.e., microhaplotypes or microhaps), compound markers (i.e., DIP-STRs, SNP-STRs and DIP-SNPs) and lineage markers (i.e., rapidly mutating Y chromosome STRs) that improve the deconvolution of two and more than two-person mixtures typed using conventional STR, binary and non-binary loci. We explore the features and applications of these emerging molecular biomarkers with respect to their ability to forensically detect same-or-opposite sex donors. Finally, we discuss the impact of initial massively parallel sequencing (MPS) investigations of STR, microhaplotype and SNP/indel assays for DNA mixture profiling.