Posted: Apr 09, 2018 4:39 pm
by Sendraks
The_Piper wrote:
Papa Smurf wrote:
Sendraks wrote:Take a load of white europeans to Africa, ensure that they live mostly outdoors (rather than in nicely air conditioned houses) and within a few generations their offspring will be noticeably darker skinned.

Seems to me that would only be true if dark skin would be selected for by those with lighter skin dying of skin cancer. If sunscreen gets used properly (or more in general if medical care keeps them alive until after they have reproduced) they would stay white as lilies :grin:

Or is it possible that extensive exposure to sun activates previously inactive genes in an individual and this gets passed on genetically through sperm?

I think the lighter/darker skin color difference has to do with vitamin d uptake. Lighter skin absorbs more. Maybe taking vitamin d capsules negates that selection pressure now. My point about our distantly future generations surely evolving into a different order of mammals might also be negated by man-made factors.

Papa makes a fair point, it is unlikely to be just a few generations but, I think I read something a while back about melanin production in humans and it being much more adaptable. However, I can't find the source to back it up, soooo its probably a wash. :(

What I do know is that the process of evolving from paleskinned hairy apes living in forests to dark skinned hominids out on the savannah, was a process of change over millions of years. Whilst the change from dark skinned hominids to pale skinned europeans, took only a couple of hundred thousand years. And there is some genetic research around how the genes controlling melanin production are more responsive to changes in circumstances.