Coyote writes:
I had a class in Human Races in graduate school.
And it is even more complex than you point out.
Too right!
Most racial classifications rely on visible traits, but there are the invisible traits as well.
Yes, and that's where it gets really interesting.
Here's a diagram showing the distribution of one interesting Y chromosome Haplogroup. The mutation is thought to have arisen about 18,600 years ago in North-eastern Africa. (Click to enlarge).
If we put together a group with a couple of people from each country covered here who are in the E-M78 Haplogroup, it would appear to be a very multiracial group. However, for one genetic characteristic, we could call them a family with a common male ancestor less than 20,000 years ago.
We will all be in unlikely looking groups if we are classified by certain characteristics. This is one of the reasons that "race" is a sort of nebulous concept biologically speaking.
Haplogroup E-M78