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

Change how you’re framing the thought. It’s 100% human DNA. But DNA undergoes mutation so there are small variants among every single human who isn’t a twin.