system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5. How do websites like ‘Ancestry’ and ‘23 & me’ work?

I am not sure if it is the altered state I am in, but I can’t seem to understand how these websites are able to track back so far before DNA could be analyzed and understood or even known?!
gpt
They compare your DNA to the DNA of modern people in other regions. Their equipment is meant to search for certain common markers with other groups. So let’s say they take your DNA and run it through their database. They find that your DNA is most similar to people who live in southern Italy and you also have some similarities with Hungarians. Your results come back mostly Italian and partially Hungarian.