Forensic onychology: An essential entity against crime.

Forensic Onychology (Greek word, Onuks = nail, Logia = study of) is the subject which deals with study of fingernails and toenails for better administration of justice in the court of law. Identification means determination of individuality of a person. Nails are important tissues for human identification. One of the major advantages of utilizing nail is that, in comparison with other tissues, sample size and sampling process can be considered relatively non invasive and non destructive and yet each nail retains a discrete record of detailed information on genetic inheritance, drug use, pathology, diet and location history as well as exposure to explosives residues or other pollutants. In contrast to soft tissues, nails survive relatively well in the decomposition environment. Furthermore, in contrast to other long lasting tissues (such as bone and teeth) nails are easy to decontaminate from external sources of DNA. Thus examination of nail is very useful in many ways against crime. In this paper, we discussed about structure and method of analysis of nail, utility of examination, drug use and nails and detection of DNA from nails.

Application of victims' fingernails in Forensic DNA analysis.

DNA extracted from the victims’ fingernails may assist in the identification of the aggressor. Fingernails were collected from 8 victims, and were subjected to DNA extraction using the Kit « Tissue and Hair Extraction Kit (Promega) ». All samples were typed for 15 autosomal short tandem repeats and for amelogenin using the Kit « Powerplex TM16 system (Promega) » and the ABI Prism 310 DNA sequencer. The profiles obtained were compared with those achieved by similar typing of victims’ and suspects’ blood. In two Forensic investigations, mixed genotypes were detected in DNA extracted from the nails: Alleles originating from the victim were coamplified with other alleles that matched the suspect’s genotypic profile. This indicated that victims’ fingernails contained biological material (blood, epithelial cells) originating from the suspect. Our results confirmed the usefulness of the nails as a specimen for forensic identification of the aggressor.