blue eyed evolution

[cruzist]

I read somewhere that modern humans came out of Africa about 150,000 years ago, and largely replaced previous homos living in Europe and Asia. Presumeably these modern peoples were all brown eyed.

It has occured to me that blue eyes in people may be a very recent development, but I have been unable to find any discussion of how old this trait might be.

Can anyone answer this question or point me in the right direction? I am not a scientist, but just have a question.

thanks

[Sisyphus]

I've heard some people think the blue-eyed gene might have come from cross-breeding with neandertals, which seems plausible enough, but in trying to research it online I only managed to find a few extremely dubious articles on white pride and ultraconservative websites before I gave up in disgust. That might still be something to look into, though.

[aguy2]

I read somewhere that modern humans came out of Africa about 150' date='000 years ago, and largely replaced previous homos living in Europe and Asia. Presumeably these modern peoples were all brown eyed.

[/quote']

 

Why would we 'presume' they were all brown eyed?

 

aguy2

[Aardvark]

Why would we 'presume' they were all brown eyed?

 

aguy2

 

Possibly because present day African populations are all brown eyed. This indicates that the development of blue eyes happened after, rather than before human populations migrated out of Africa.

[Daecon]

Couldn't you say the same thing about light hair and pale skin?

 

I'd have thought it was a natural progression along the same characteristics, being in an environment where deep pigmentation isn't that important to survival from hot bright climates anymore?

[Bluenoise]

Okay, the neaderthal idea stems from a lack of knowledge about eye clour.

 

Basically preople with brown eyes produce alot of melinin and people with blue eyes produce very little. It takes only a very simple mutation to go from one to the other. It's not like you're getting a completely different pigment

 

Oh and green, grey, etc are somewhere inbetween.

 

Basically you can expect the alleles to mutate to the alternative form fairly quickly. Like people with blue eyes will appear in african populations randomly. It's just their eyes absorbe to much light and it's a slight disadvantage. So under selective presures they allele gets pushed out of the population.

 

 

Like for example white homozygous mice if placed in a dark environment, like an old lavaflow will evolve a black fur colour withing a few thousand generations. I'm pretty sure that this is due to the same pigement melinin. And going from dark to white is even quicker since it is more likley for a mutation to decrease a gene product than promote one.

[bombus]

Bluenoise is correct. Blue eyes are linked to a pale skin which is an adaptation displayed by peoples living in european northerly climates. The reason for it is because northerly latitudes have lower sunlight levels which make the production of vitamin D by the skin from sunlight more difficult. ('Eskimo' type peoples have other adaptations for living in even colder latitudes but probably retain brown eyes because they traditionally have a diet rich in vitamin D and also need dark eyes due to snow and sand glare).

 

The eyes of negroid peoples are not brown in exactly the same way as indo-europeans though, as it also involves pigmentation of a different part of the iris.

 

I don't think the Neanderthal reason is really 'needed' for an explanation, but I wouldn't discount it totally as there may be other peoples who lived in similar conditions to early europeans who never developed blue eyes...

[Daecon]

You mean African peoples?

[Sisyphus]

I don't think the Neanderthal reason is really 'needed' for an explanation, but I wouldn't discount it totally as there may be other peoples who lived in similar conditions to early europeans who never developed blue eyes...

 

Seems like east/central Asian peoples and American Indians would fall into that category. But then again, maybe they're relatively recent newcomers to their respective regions...

[Milken]

First and most importantly, of all the people living we're of ONE race, homo sapien, anything less is racist. It's really an intersting issue because it's contradictory to evolution

 

ALL of us have melanin, just to different degrees, so essentially we're all SHADES of the same color. As stated earlier, those who can absorb alot of sun( get darker ) also get a lot of Vitamin D (I also thought it was E also). Nonetheless, deficiencies in the vitamin have been known to lead to mental instability. Homo sapiens without melanin retain more of the Vitamins

 

Back the original idea of it being contradictory to evolution. . . having a lot of melanin (dark skin), dark hair, eyes, etc, are DOMINANT GENES. It's possible for two dark people to have a lighter skinned child or even one with randomly blue eyes. But the other way around is IMPOSSIBLE.

 

In other words, if both your parents are very pale, and you stay dark year round, congradulations, you're adopted, or someone has been sleeping. . . lol.

[mrblond5311]

Bluenoise is correct. Blue eyes are linked to a pale skin which is an adaptation displayed by peoples living in european northerly climates. The reason for it is because northerly latitudes have lower sunlight levels which make the production of vitamin D by the skin from sunlight more difficult. ('Eskimo' type peoples have other adaptations for living in even colder latitudes but probably retain brown eyes because they traditionally have a diet rich in vitamin D and also need dark eyes due to snow and sand glare).

 

The eyes of negroid peoples are not brown in exactly the same way as indo-europeans though' date=' as it also involves pigmentation of a different part of the iris.

 

I don't think the Neanderthal reason is really 'needed' for an explanation, but I wouldn't discount it totally as there may be other peoples who lived in similar conditions to early europeans who never developed blue eyes...[/quote']

 

 

 

So if my wife consumes less vitamin D and avoids the sun while she's pregnant there's a better chance of my son coming out with blue eyes? We're both caucaian and she has red hair, pale skin, & dark blue eyes; I have brown hair, year round tan, and dark brown eyes. I'm just curious if maybe I have dominant genes because all of the males on my dads side look the same, including me and my first son. My second son came out with dark hair, dark skin, dark blue eyes (for now). He looks like a mini me except for the eye color which would be a first on my dad's side for a while. What would it take to have my gene for the eye color "overpowered" so to speak?

[Milken]

1.So if my wife consumes less vitamin D and avoids the sun while she's pregnant there's a better chance of my son coming out with blue eyes?

 

 

2. We're both caucaian and she has red hair' date=' pale skin, & dark blue eyes; I have brown hair, year round tan, and dark brown eyes. I'm just curious if maybe I have dominant genes because all of the males on my dads side look the same, including me and my first son. My second son came out with dark hair, dark skin, dark blue eyes (for now). He looks like a mini me except for the eye color which would be a first on my dad's side for a while. What would it take to have my gene for the eye color "overpowered" so to speak?

 

[/quote']

 

1. ABSOLUTELY FALSE, YOU AND YOUR WIFE'S GENETIC HISTORY WILL DETERMINE IT.

 

 

2. TOUGH QUESTION, GENERALLY SPEAKING BLUE EYES, RED HAIR, AND PALE SKIN ARE ALL RECESSIVE GENES.

[Aardvark]

1. ABSOLUTELY FALSE' date=' YOU AND YOUR WIFE'S GENETIC HISTORY WILL DETERMINE IT.

 

 

2. TOUGH QUESTION, GENERALLY SPEAKING BLUE EYES, RED HAIR, AND PALE SKIN ARE ALL RECESSIVE GENES.[/quote']

 

Please don't shout.

[Milken]

Please don't shout.

 

LOLOLOLOLOLOLOLOLLOLOLOLOLOLOLOLOL

 

Accident, originally it was suppose to be inside the quote to distinguish my words from theirs.

[Daecon]

Or you could just use bold.