Interestingly, the day Barack Obama won the Presidency, I listened to a section about race in the book. Dawkins uses Colin Powell as an example, but Obama would work just as well. According to Wikipedia:
Barack Obama was born at the Kapi'olani Medical Center for Women & Children in Honolulu, Hawaii,to Barack Hussein Obama, Sr., a Luo from Nyang’oma Kogelo, Nyanza Province, Kenya, and Ann Dunham, a white American from Wichita, Kansas of mainly English, Irish and smaller amounts of German descent.
Obama is therefore just as much white as he is black. So why is he, by default, considered black? Dawkins points out that genetic characteristics such as skin color are not the product of dominant and recessive genes, as in eye color. The child's skin color is more often the result of a blending effect of the genes that control it. Blacks more often have brown eyes, which are dominant, and so perhaps there is somehow the perception that certain racial traits contribute more to appearance than others.
Dawkins points out that there is no objective biological criteria for designating race, and that it really is a subjective category. In reality, it makes as much sense to call Obama "white" as it does "black".
I admire the way Obama has transcended race by mitigating its importance. Hopefully we'll get to a point where we don't don't make judgments, legal or personal, based on somewhat arbitrary racial categories, and hopefully Obama's Presidency will be a step toward that point.