When it comes to identification with DNA, forensic scientists have two basic approaches at their disposal. One approach analyzes nuclear DNA and is useful in identifying someone who is alive or has died only recently. This is the technique used to incriminate (or exonerate) suspects of crimes and in paternity testing. It's also the one used to identify the remains of victims of the September 11th attacks. The other approach analyzes mitochondrial DNA, or mtDNA. …showed first 75 words of 439 total…

…showed last 75 words of 439 total…lines, forensic scientists can use it to assist with the identification of someone who died long ago by matching that person's mtDNA to any ancestor or descendant on that line. This wouldn't be possible, however, if mtDNA wasn't as long lived as it is. Because there are so many more copies of mtDNA within the cells of our bodies, mtDNA tends to be around, even in bone fragments, long after nuclear DNA has fallen apart