Our genetic history can now be traced, thanks in part to DNA extracted from fossils. Credit: AP/Francois Mori 

As scientists apply our new understanding of the human genome to genetics, we’re getting answers to big-picture questions about our species. What is race? How did humanity spread around the globe? How should we pick a mate (genetically speaking)? We talk with Adam Rutherford, geneticist and author of "A Brief History of Everyone Who Ever Lived," about the history of our genes, and what they reveal about our species.

Three Takeaways 

• Don’t marry your sister. Seems like pretty obvious advice, right? Rutherford says we should ideally reproduce with people who are as genetically different from us as possible, if we want to reduce the chance of inherited diseases.
• Our earliest ancestors were quite friendly, mobile people. Homo sapiens emerged from Africa and bred with European Neanderthals and other human species, spreading their DNA around the globe.   
• Race doesn’t exist (from a genetic point of view). Rutherford says there’s a big disparity when it comes to the physical characteristics we use to identify race (like skin color) versus our actual DNA. For example, a black person from New York might have a more similar genetic makeup to the leader of China than to a black person from Boston.

More reading 

• Rutherford is a bit of a hip-hop fan. Hear him explain what it can teach us about synthetic biology. 
• Charles II of Spain is a perfect example of why inbreeding is not such a good idea. Discover Magazine explains why.
• The New York Times asks whether we should ignore race when it comes to medical treatments.