On Westwood Boulevard in Los Angeles, just off the University of California campus, the street is jammed at lunchtime. The tones of all humanity flow past, faces from Santa Monica, Singapore, and Senegal, a stroboscopic stream of light and dark.
Notwithstanding such contrasts in appearance, comparisons of our DNA show that human populations are continuous, one blending into the next, like the spectrum of our skin coloring. We all carry the same genes for skin color, but our genes responded differently to changes in solar intensity as bands of Homo sapiens migrated away from the unrelenting sun of the equator.
Still, it seems to be human nature to assign types to our fellow humans and then make judgments based on those types. Take this tall woman coming along the sidewalk and entering an Italian restaurant. Blond, but not California blond. In her early fifties, wearing a stylish suit and elegant ...
