Analysis of Mitochondrial DNA on Earwax as an Alternative Material for Present and Future Forensic Examination

Abstract

Introduction: Nowadays molecular forensics is a field of science evolving since the1980s, known as DNA fingerprinting. Specimens widely used in DNA examine for identification are blood spots/bloods, semen spots, vaginal swabs, buccal swabs and bones. In addition to these samples, the last objects often used by the perpetrators/victims can be hearing assistive devices or/and hearing aids(headsets/earphones). In its use, earphones are attached to the outer ear skin; therefore, the earwax is suspected to stick to the device. Cerumen have been investigated for the last decades finding an important way to detect specific variations in the mitochondrial DNA (mtDNA) of this type of corporal fluid. The present study discusses relevant information about the literature and how this method is the future for new findings in forensic sciences.Discussion: Literature showed that Mitochondrial DNA has better durability and relatively higher number of copies than those of nuclear DNA. This leads to greater possibility of success in amplification, given the higher number of mitochondrial DNA copies and the fact that mitochondrial DNA is a single locus that allows recombination. It is controversial the use of earwax as a possible DNA identification tool because of the environmental factors of exposure duration. Controversially, literature shows that this type of fluid has a great opportunity in terms of cell replication and DNA identification. Conclusions:The mt DNA contained in earwax samples potentials to be a new identification sample for the forensic science. Present studies provide promising evidence for the use of this fluid in different types of identification procedures.