Science Questions

I've heard that there's a single origin for the emergence of Homo sapiens. Is there any scientific background to this claim? Andrew in Arizona

It's pretty difficult to say exactly where we came from, but the evidence is stacking up that we came from Africa, probably about 100 000 years ago. This is based on a combination of looking at the Y-chromosome in DNA, which is the male line, and also mitochondrial DNA, which you have to inherit from your mother. There's a lot more diversity in Africa than anywhere else, and it looks like we can track the migration of humans around the world. East Africa is looking pretty good as our origin.

December 2005