Can skin histology be a useful tool for ancestry assessment in forensic settings? Ancestry assessment based on melanin pigment

Building the biological profile of a deceased person represents a pivotal step in order to achieve the victim's identification. Specifically with regard to ancestry, the melanin distribution pattern in the dermal-epidermal layers has been poorly explored in the forensic field as a potential useful tool. In particular, nothing has been reported about the reliability of such method in bodies in active decay or in advanced state of decomposition. In this study fragments of skin sampled from bodies of known ancestry, both in good and in poor states of preservation, were subjected to histological analysis. We selected 15 subjects, which were divided into three groups: group A (5 white Europeans), group B (5 black Africans) and group C (5 Orientals). A double skin sample was performed on all the bodies, one from the abdomen and the other one from the right forearm. After histological processing and staining with hematoxylin and eosin (H&E) and Masson-Hamperl trichrome technique, the cutaneous melanin distribution pattern was assessed using a semi-quantitative score. The melanin distribution patterns observed both in fresh and in putrefied cadaveric skin were found to be in all cases consistent with the victims’ known ancestry. Moreover no differences were observed between abdominal and forearm skin samples and all the histological findings highlighted by H&E were confirmed by the Masson-Hamperl trichrome staining. We demonstrated that the histological analysis aimed at assessing the melanin distribution pattern may be a valuable useful tool in the assessment of ancestry.