Why would a DNA heritage test say you are from a particular place if that particular place was occupied by multiple other empires historically?

Question

For example, my test came back Sicilian, and British. But both places have had various other countries occupy them in the past.

In: Biology

Answer 1

All the DNA tests say is that in a certain location there’s more people with genetic markers they test that are similar to yours, compared to the frequency of those genetic markers in other places. It doesn’t say you are from anywhere. It just says that your specific couple of markers are common in Sicily. It doesn’t mean that people with those markers don’t exist elsewhere. That being said, who occupied Sicily is irrelevant, they are comparing your DNA of today with the people who gave samples today (or over the past couple of years that commercial DNA testing became popular and available).