mtDNA exploitation in forensics

Degraded DNA samples often fail to produce profiles suitable for individual identification with the conventional nuclear short tandem repeat markers. However, recovery of genetic profiles from degraded DNA is sometimes possible with mitochondrial DNA (mtDNA). mtDNA is present in much higher copy number in the human cell than nuclear DNA; it is maternally inherited and is not subject to the phenomenon of genetic recombination. Therefore excluding the occurrence of mutational events, the mitochondrial molecules will be passed without modification to the mother’s children and maternal relatives share an identical mtDNA genome. The main exploitation of mtDNA in forensics is related to the reconstruction of genetic relationships in case of missing person’s identification or mass disaster investigations. In addition, mtDNA analysis can provide useful results in forensic samples with damaged DNA as bone remains, teeth, hair, and hair shafts. This chapter will review the features of mtDNA, the steps necessary to obtain results in forensic casework, and issues important to interpreting results.