Then imagine yourself naked.
Then look at the patch of skin on the inside of your upper arm, the part of you that almost never sees the sun.
Whatever color you see there is what experts call your basic skin color, according to professor Nina Jablonski, head of the Penn State Department of Anthropology.
And that color, the one you have now, says Jablonski, is very probably not the color your ancient ancestors had — even if you think your family has been the same color for a long, long time.
Different Place, Different Color
Skin has changed color in human lineages much faster than scientists had previously supposed, even without intermarriage, Jablonski says. Recent developments in comparative genomics allow scientists to sample the DNA in modern humans.
By creating genetic "clocks," scientists can make fairly careful guesses about when particular groups became the color they are today. And with the help of paleontologists and anthropologists, scientists can go further: They can wind the clock back and see what colors these populations were going back tens of thousands of years, says Jablonski.
She says that for many families on the planet, if we look back only 100 or 200 generations (that's as few as 2,500 years), "almost all of us were in a different place and we had a different color."
Over the last 50,000 years, populations have gone from dark pigmented to lighter skin, and people have also gone the other way, from light skin back to darker skin, she says.
"People living now in southern parts of India [and Sri Lanka] are extremely darkly pigmented," Jablonski says. But their great, great ancestors lived much farther north, and when they migrated south, their pigmentation redarkened.
"There has probably been a redarkening of several groups of humans."
