Challenges in the recovery of the genetic data from human remains found on the Western Balkan migration route.

Traditional DNA-based identification of human remains relies on the system of matching STR profile of the deceased with the family references or antemortem samples. In forensic cases without any available samples for the comparison, the body remains unidentified. The aim of this study was to assess the applicability of massively parallel sequencing (MPS) approach in the forensic cases of five drowned individuals recovered on the Western Balkan migration route. Besides capillary electrophoresis (CE)-based genetic profiling (aSTR, Y STR, and mitochondrial control region sequencing) of postmortem samples, we applied ForenSeq DNA Signature Prep Kit/Primer Mix B on MiSeqFGx platform and concomitant ForenSeq Universal Analysis (UAS) software. The assay showed high reproducibility and complete concordance with CE-based data except in locus DYF387S1. Allele and locus drop was evident in 2.9% of total SNPs that slightly reduced the completeness of the data. We endeavored to predict the phenotype of the tested samples and accurate biogeographical ancestry of European individual. UAS was less informative for the remaining samples assigned to Admixed American cluster. Nevertheless, the application of FROG-kb and Snipper tools along with admixture analysis in STRUCTURE and lineage markers revealed likely Middle Eastern and North African ancestry. We conclude that the combination of the phenotype and biogeographical ancestry predictions, including paternal and maternal genetic ancestry, represent a promising tool for humanitarian identification of dead migrants. Nevertheless, the data interpretation remains a challenging task.