They should probably be looking at the Y chromosome.
Forgive me if i'm wrong, but as i understand it, this would be very difficult/nigh impossible. The y chromosome has very little actual " understand that the Y is fairly generic. I'm fresh from high school bio, and i did very well in it. One of the things my teacher taught was why men get screwed when it comes to genetic disease. Women, in order to have a recessive genetic disease, need to have both of their X chromosomes to have that disease. Men only have one X, so all it takes for a man to have a recessive genetic disease is for that X to be defective. The point of this is, many fewer genes exist on the Y than X, so like I said, the Y has very fewer features to track. Besides, there are many other chromosomes and genes that one could track much more easily, I think.

For all those that care or don't understand:
Mitochondrial DNA is also extranuclear, meaning outside the nucleus. It is located with mitochondria, the powerhouse of the cell. The mitochondria are all inheirited from the mother, because the sperm contains only DNA, and could not possibly donate mitochondria paternally.

Unless my teacher and book are asses, i think this is pretty accurate. Just my 2 cents anyways