Why do lighter-skinned folks have more diverse hair colour?

[Yom]

I always thought the variation had to do with melanin and other pigments. That is, I thought dark-skinned people have enough melanin and melanocytes in our skin and hair for our hair to only appear black, masking the other pigments. On the other hand, I thought because there is less melanin in lighter-skinned people, other pigments such as carotene.

Edit: Wikipedia says that the grade in hair color is all due to melanin, so it would make sense if light skin necessarily meant you have light hair, but this is obviously not the case upon visiting the Middle East or East Asia.

Edit: Apparently eye color is determined by melanin, too.


Here's a link to a video about hair color a little while ago. I don't remember if it talked about the evolutionary aspects, but it did talk about the hair cycle, color, and some things about graying; I don't have time to watch it for the information right now, though.

Wow, there are some even better ones on hair.
Link1
Link2

 

[Stapel]

I've always wondered why West-Africans are often full of muscle, while East-Africans are often so skinny.

 

[Chieftess]

I've always wondered why West-Africans are often full of muscle, while East-Africans are often so skinny.

East-Africans (Kenyans especially) always seem to have the top runners in marathons and running events. (They'd give the Greeks a run for their money. ). But, that's not about hair...

 

[thestonesfan]

What's odd to me is that exposure to the sun will lighten a white persons hair, while it darkens the skin. My hair definitely gets lighter if I've spent a lot of the summer outside.

 

[Stapel]

What's odd to me is that exposure to the sun will lighten a white persons hair, while it darkens the skin. My hair definitely gets lighter if I've spent a lot of the summer outside.

Same here. I just returned from the alps, and I'm tanned and more blond...

 

[thestonesfan]

It probably has something to do with hair being dead tissue and skin being living.

 

[wit>trope]

Here's something - all the half-Chinese I know have brown eyes and dark brown hair, even if their non-Chinese parent is blonde and has blue or green eyes. Their features are a mix of Chinese and Caucasian. It seems to be as if the genes for brown eyes and dark hair are much more dominant than those for light coloured hair and eyes.

I've seen a half-East Asian with a mix of black or dark brown and blonde hair before. I don't know if it was because he dyed it or because of the mix of races.

If you're right about the dominance of genes then that's not good news. With all the inter-racial or inter-ethnic marrying* that would mean blonde people will become extinct I like blondes and I hope they never become extinct. All things being equal blondes are prettier than brunettes.

*I guess it's no longer inter-racial or inter-ethnic for a blonde to marry a brunette since all the European races have mixed together so much that they have all lost their character and effectively become extinct. My high school german teacher told us that it didn't used to be this way and that once you could tell by hair color, etc. whether someone was from this nation or that nation in Europe.

 

[The Last Conformist]

There was a newspaper report claiming that blonde hair will disappear due to race mixing and the low fertility of the blondest populations in a century or two. I'd be rather doubtful as to the reliability of that, tho.

 

[wit>trope]

There was a newspaper report claiming that blonde hair will disappear due to race mixing and the low fertility of the blondest populations in a century or two. I'd be rather doubtful as to the reliability of that, tho.

Did it say anything about white skin disappearing too? It seems like race mixing (I mean not just within European races but also between white and non white races) would cause white skin to disappear too since the Hispanics don't have white skin anymore. I have nothing against inter-racial or inter-ethnic marriage but an unfortunate consequence of it is these kinds of things and also the loss of diversity.

 

[Xen]

Did it say anything about white skin disappearing too? It seems like race mixing (I mean not just within European races but also between white and non white races) would cause white skin to disappear too since the Hispanics don't have white skin anymore. I have nothing against inter-racial or inter-ethnic marriage but an unfortunate consequence of it is these kinds of things and also the loss of diversity.

keep a hispanic person out of the sun for a while, and the'll be plenty pale.

 

[wit>trope]

But not as white as they used to be before the race mixing, so something was still "lost" no matter what you want to call it

I think it would be a shame to lose blue eyes too. Blue is one of my favorite colors But I guess they have those color contacts now. I don't know if they can make brown eyes blue though.

 

[The Last Conformist]

Did it say anything about white skin disappearing too?

No, it didn't.

 

[Uiler]

I've seen a half-East Asian with a mix of black or dark brown and blonde hair before. I don't know if it was because he dyed it or because of the mix of races.

Most likely dyed. Dying your hair with blonde hightlights (or even the entire hair) or with red highlights is very fashionable amongst East Asian youths. In fact it's so common I'm keeping my hair black just to go against the "cool" trend.

 

[thestonesfan]

There really isn't a great degree of race mixing going on, I don't think. There's a crazy lot of white people in the western world.

 

[Renata]

Neither blonde hair nor pale skin is ever going to disappear, no matter how much racial mixing goes on. Nor will it lessen genetic diversity. Genes are discrete things; they don't mix. Hair color is controlled by several genes, but the basic idea is as follows: A child of a blond person will always have one copy of a "blond-hair" gene, no matter the color of their own hair. If that person has a child with another dark-haired child of a blond person, any children will have a 25% chance of being blond themselves. (Roughly speaking. Since there are multiple genes involved, it's not quite this simple.) As a concrete example, my parents both have darker hair than either my sister or I do -- my sister is blond, and I have very light brown hair, where my parents have medium-brown and dark brown hair.

Skin color is controlled by a large number of genes, so variation exists on even more of a continuum than with hair color, but again, the genes themselves exist as discrete units. So depending on ancestry, two dark-skinned people could have a very light-skinned child. Interestingly, the same is not true in reverse: two blond or white-skinned parents cannot produce a dark-haired or dark-skinned child.

Renata