Naked Science Forum

Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: chefelf on 26/04/2009 17:28:44

Title: How long would it take for skin pigment to change through evolution?
Post by: chefelf on 26/04/2009 17:28:44

I'm just curious if anyone has any calculations as to how long it would take a human being's skin pigment to change through evolution.  Does anyone have any info on this?

Title: How long would it take for skin pigment to change through evolution?
Post by: Kryptid on 28/04/2009 21:23:27

In principle, it could happen in one generation. Put the right kind of mutation in the right gene and you could end up with drastically different skin pigments. Even a single nucleotide substitution can have far-reaching effects. Sickle-cell anemia is caused by just such a mutation, for example.

Title: How long would it take for skin pigment to change through evolution?
Post by: BenV on 28/04/2009 23:13:35

It would depend greatly on the strength of selective pressure.  I suspect that it would be much quicker on the equator compared to in northern europe/the UK.

You also have to bear in mind that the ability to tan is an evolved trait.

Title: How long would it take for skin pigment to change through evolution?
Post by: Bored chemist on 29/04/2009 20:35:11

If some mutation gave rise to a change in skin colour that wouldn't necessarily be evolution. If that colour- lets say purple- tunrend out to be popular so their offspring found it easy to find partners that might be evolution.

However evolution could, in principle change skin colour in 1 generation (pretty much).
Imagine a totalitarian society where the leader (perhaps having got bored of renaming things like bread after his mother) decided that all white people should be exterminated.
That would be evolution- having white skin would be a lethal mutation in those circumstances and so it wouldn't reproduce.

The thing that drives evolution is selection. If the selective pressure is high enough evolution can work very quickly.

OK, I can see you are thinking that's a weird situation, and for humans it would be.
Now imagine you are a bacterium that happens to have the genes for penicillin resistance, and someone fills the environment with penicillin.