Some news about human skin color

A recent report on National Public Radio details new findings in the genetics of human skin color. (The report is in text form, but the page has a link to an audio report, which is a little over seven minutes long. Robert Krulwich, science correspondent, is always interesting to listen to.)

Krulwich interviewed Nina Jablonski, an anthropologist. She believes that human skin color has changed, within groups of humans isolated from each other, because of selection, as such groups migrated North or South. Dark skin color, caused by deposits of melanin in the skin, tends to protect people from excess Ultraviolet light, which may cause skin cancer, and groups who have historically lived near the equator have darker skin than those who have lived further North. On the other hand, having lighter skin allows the person to absorb enough UV light to assist them in manufacturing sufficient vitamin D.

All of this was reasonably well understood before Jablonski's findings. Her research indicates, in addition, that many human lineages have migrated, and, in as little as one or two hundred generations, have changed their skin color from light to dark, or the reverse. For example, the Indians (of Asia), according to Jablonski, are now dark-skinned, but were not always -- they lived further North, and were lighter-skinned. Jablonski believes that humans originated in Africa, where they had darker skins.

Interesting. Thanks for reading.