Nails as optimal source of DNA for molecular identification of 5 decomposed bodies recovered from seawater: from Y-ancestry to personal identification

Molecular identification of extremely compromised human remains in forensic field is usually performed from DNA typing of bones, which are a difficult sample to work with. Moreover, autosomal STR profiles do not always result in the identification of the donor due to lack of comparisons or non-hit throughout database searching. An attempt to overcome these issues is represented by fingernails as an alternative DNA source and Y-STRs typing to infer both geographical and familial ancestry of the unknown donor. In this study, we analyzed both 24 autosomal and 27 Y-chromosome STRs from unidentified human remains (UHRs) of five males recovered from the water near the southwestern coast of Sardinia by the Italian Harbor Master's Office. Nail clippings provided an optimal source of autologous DNA for molecular identification in a very short time, producing complete autosomal and Y-STR profiles even under conditions of high body degradation. Unfortunately, no match neither compatibility occurred using autosomal STRs (aSTRs), initially. Upon analyzing the Y-haplotypes, we found out they had already been observed in northern Africa, providing us important investigative leads. This prompted the International Criminal Police Organization (INTERPOL) to provide us with references of alleged relatives that were then confirmed to be related. The use of fingernails represents an excellent DNA source especially for genetic identification of decomposed bodies recovered in seawater environment. Notably, DNA extracted from nails gave high-quality Y-STR haplotypes by which predicting paternal ancestry of the unidentified donors may result fundamental in the forensic investigative context.