Wow, this sounds like a really great idea. Except that 50 generations ago, there were theoretically 2^49 possible contributors to my DNA. Of course that number, 562,949,953,421,312, is far greater than the total number of humans who have ever lived, which implies that most of my ancestors must be "repeats". To put that another way, we are ALL inbred in the grand scheme of things. A familial relationship can be established between any given pair of living humans by going back less than 50 generations. That's right, Malcolm X and the Grand Wizard of the KKK are cousins. You knew that already -- it's not like there's anywhere else for humans to come from than other humans.
The implication for this purported study, I think, is that it is nonsense. Pick any living human, and any 1000-year-old town. Yes, that person "came from" that town.