Why is mitochondrial DNA useful for forensics?
Two reasons. First, mtDNA is passed along largely unchanged from mother to offspring. That means your mtDNA resembles the mtDNA not only of your mother but your mother’s matrilineal relatives: for example, her other children, her mother, her siblings and her sisters’ children. A sample from any of those relatives could be compared with your mtDNA to identify you as a relative of your mother. (It can’t prove exactly how you are related, though.) Second, mtDNA samples can be collected from decayed tissue, including bones. It can even be extracted from Ice Age mammoth bones. How is mtDNA extracted from bone? The scientist slices off a quarter of a gram of bone, crushes it and uses chemicals to remove proteins and minerals. She adds silica particles that bind to the DNA and separate it from the other substances. So little DNA exists in bone that it is necessary to make copies for analysis. The mtDNA is targeted with the aid of chemicals. A heating and cooling process is used to separate th
