I recorded a Science News Flash podcast today with Dr. Fuz Rana about a new study published online on the Science web site.
Here is a link to the news story on Yahoo!: "Africans have world's greatest genetic variation"
Here is the link to the podcast: Africans have world's greatest genetic variation
You'll hear me mention Dr. Rana's book, Who was Adam?, in the podcast. I'd highly recommend it if you want more information on this topic.