Rapidly mutating Y-STR analyses of compromised forensic samples
Rapidly mutating Y-chromosomal short tandem repeats (RM Y-STRs) were identified to improve differentiation of unrelated males and also to enable separating closely and distantly related males in human identity testing in forensic and other applications. RM-Yplex assay was developed as a single multiplex that is capable of simultaneously amplifying all currently known RM Y-STRs, and reproducibility and sensitivity testing were performed on reference samples. Additional analyses are necessary to test its suitability for analysing compromised forensic samples. For this purpose, we applied the RM-Yplex assay to approximately 70-year-old skeletons that were used as a model for poorly preserved, challenging forensic samples. We analysed 57 male skeletal remains (bones and teeth) from 55 skeletons excavated from the Second World War (WWII) mass graves in Slovenia. The RM-Yplex typing was successful in all 57 samples; there were 56% full profiles obtained, and in partial profiles, up to 7 locus drop-outs were observed and they appeared correlated with low DNA quantities and degradation of DNA obtained from WWII bone and tooth samples. The longest loci, DYS403S1b, DYS547, DYS627 and DYS526b, were the most often dropped-out RM Y-STRs. In spite of high frequency of drop-out events, the RM-Yplex typing was successful in all WWII samples, showing the possibility of successful amplification of at least half of the RM Y-STRs even from the most compromised samples analysed.
KeywordsRapidly mutating Y-STRs RM-Yplex Aged DNA Skeletal remains Second World War Compromised forensic samples
The authors gratefully acknowledge Barbara Gornjak Pogorelc and Katja Vodopivec Mohorčič (Institute of Forensic Medicine, Faculty of Medicine, University of Ljubljana) for technical assistance. The authors like to thank the Governmental Commission on Concealed Mass Graves of the Republic of Slovenia for their support in excavations of the Second World War victims. This research did not receive any specific grant from founding agencies in the public, commercial or not-for-profit sectors.
Compliance with ethical standards
The research project was approved by the Medical Ethics Committee of the Republic of Slovenia (0120-156/2015-2; KME 122/06/15).
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