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

Most occupations throughout history had very little genetic imprint. The overlords vary rarely bred enough with the locals to make an impact. Britain, for instance, has been invaded and conquered several times in the past 2,000 years. Romans, Danish, Anglos, Saxons, Jutes, Normans. However, their contribution to Britain’s genetic code is fairly negligible.

But more specifically, DNA placing where people are from is usually mitochondrial. That’s a strand of DNA passed from your mother. Invading empires usually consist of men invading places and taking local wives. So the mitochondrial DNA doesn’t change.