Your mtDNA is exactly like that of your mother and hers is just like her mother's and so on back through time. Males can not pass their mtDNA on to the next generation. It's maternal mtDNA all the way back. To get into the biology of this a bit more, here is the story. Mitochondrial DNA is the genetic code that builds and maintains the mitochondria.
Mitochondria contain enzymes that convert food into energy.
They are inside the cell but outside the nucleus. In other words, they are in the cytoplasm. The longer two species have been separated, the more mutations have occurred. But if we find lots of differences then the animals are much more distantly related. The complicated part of mapping is the technique needed to do it.