DNA is used to determine where the cat was born. Almost all the midwestern cats that I know of were hatched in the Black Hills. There is a distinctive genotype that can identifies this population. They are all young males, so don't expect a big population of kitties to break out unless some females get the wanderlust - rare in female mammals. Either that, or some black helicopter work will be required. However, most black helicopters are currently too busy hauling wolves and cats will have to wait until after the grizzlies too. So don't expect imported lady cats for quite a while.
The poop can be used to do DNA analyses of the pooper, but it can also be used in stable isotope analyses and even DNA analyses to determine the origins of the poopee.
Knowing where they disperse and how they get there, gives folks some idea into where and how the populations MIGHT spread and a little bit of info about where they are unlikely to show up or what sorts of barriers might stop them.
