Last year in our Intro Biology course, I gave a couple of new lectures on human races. When you look at the genetic basis of race, you come to the conclusion below. In these lectures, I used President Obama as my example. His mitochondrial DNA is completely from Northern Europe (his mom’s ancestry), and his nuclear DNA is a 1:1 mix of northern Europe and Africa. If you only looked at his mitochondrial DNA, you’d conclude he was from Northern Europe, but if you considered his nuclear DNA, you’d get a more mixed picture. And in fact, we’re all like that.
As part of our class last year, we sequenced the genomes of all the students in the class. My sequence indicated that I’m 99.7% European, but I’m also 0.2% East Asian & Native American. So should I also tick off the Asian or Native American box on the next census form? My X-chromosome is most likely from Scandinavia (i.e., the X-chromosome I have has the highest frequency in Scandinavian populations of humans). So should I say I’m Scandinavian. But my Y-chromosome is most likely from Spain. So am I Hispanic? I also happen to be 2.7% Neanderthal, so I want that box to check for the next census as well. (Race very quickly starts to be “ethnic” and not “racial” as you can see here, too.)
This video from Vox does a great job explaining the complexities of race in a simple manner.
Speaking as a biological scientist, there is no gene for race. What we have are simply genes for skin color, and hair color and texture. Many of these traits are the result of natural selection for local adaptations (e.g., skin color), and probably sexual selection for what was considered locally attractive attributed in a mate (e.g., hair color and texture). Are those really the fundamental traits for evaluating a person (sarcasm!)? That is not to say that race is not important. As a white guy from the south, I know what “race” does and means. “Race” is mainly a cultural construct, and since culture is inherited from ancestors as well, the cultural and physical get conflated.
When you start trying to quantify race biologically (read genetically), you quickly realize that this is a futile exercise. We’re all ancestrally mosaic mongrels. If you think you’re racially “pure”, my advice to you is don’t have your genome sequenced. You are definitely not going to like what you find.