Razib of GeneExpression has a lengthy post up on a recent paper looking at the genetic basis for skin color variation in South Asian populations. A couple of interesting take-aways (as I understand them) for the person not up for reading about specific genes:
- Despite the massive cultural movements in and out of India and Europe in the last 10,000 years since the end of the last ice age, in both regions the majority of the ancestors of the population go back to the end of the last ice age.
- The highest caste (and often lightest skinned) groups within India have the highest proportion of non-Indian ancestry (going back 10k years).
- The overall skin color difference between the African and European populations is primarily the result of a single gene which is set differently in each population. Variations in skin color within each population are then the result of variation in other genes that affect skin color.
- Skin color in the East Asian population is the result of different genes, thus suggesting a longer term population separation.
- In the case of South Asians, variation in skin color is to a great extent the result of variation in the same gene that controls the primary difference between European and African skin coloration -- and yet the appearance of that gene doesn't seem highly correlated to other neutral markers that would suggest European genetic input. That suggests that both populations have independently begun selecting for the same mutation in that gene (producing light skin color) within the last 10,000 years.
Anyway, if that's not already genetics for you, go check out Razib's post, since he actually knows what he's talking about, and I'm just a clever and interested parrot. Or, if you've no interest in genetics, some may still want to check out the Bollywood babes whom Razib uses to illustrate his skin tone point. You know who you are.
UPDATE: See Razib's comment for a few clarifications, explanations on my bullets above.