Mitochondrial DNA has more useful genetic information as compared to nucleic DNA because they are present in more number per cell. In decomposed or old biological samples nuclear material in the cell may not exist for a long period, so it is difficult to perform DNA analysis with the nuclear DNA from remains of biological samples. This high copy number in mtDNA increases the possibility of recovering sufficient DNA from compromised samples. For this reason, mtDNA can play an important role in the identification of missing person investigation, in mass disasters and other forensic investigations involving samples with limited biological material. Additionally, mtDNA is maternally inherited. Therefore, barring a mutation, an individual's mother, siblings, as well as all other maternally-related family members will have identical mtDNA sequences. As a result, forensic comparisons can be made using a reference sample from any maternal relative, even if the unknown and reference sample are separated by many generations. Anthropologically, mitochondrial DNA in the fossilised source is used to trace the human ancestry particularly of maternal lineage.