If humans originated in Africa, how can we have anything other than 100% African DNA?

Question

is there some sort of cutoff point where scientists decided “everyone in Ireland 100,000 years ago will be considered 100% Irish”?

In: 12

Answer 1

There have been mutations in human DNA since the Out Of Africa migration. Of course, there were also mutations in Africa during that time. So in a sense, no one has (ancient) African DNA. Instead, we’re all at different points on a tree that begins with ancient African DNA and descends down to the present.

However, non-African populations all share some early mutations. In other words, they form one cluster on that tree, while native African populations form another. It’s in that sense that Africans tend to have one set of genetics while everyone else tends to have another.

On the other hand, if you go further up the tree, humans share our DNA with other species from which early humans diverged long before the Out Of Africa migration.