Geneticists Shake UP the Mix Again

[Beagle]

There are many other adaptations that occurred. For instance, modern Europeans have far fewer sweat glands that modern Africans. It's a cold weather adaptation.

But the OOA supporters contend that these changes happened since ca 40kbp.

[Digit]

Allowing for my limited understanding of modern genetic theory Beag I have to apply Mendel's ideas and some logic.
I see no problem a with a gentic change resulting in a change in colour, and I have no doubt that the theorists could calculate how rapibly such a change could spread though a given sized population.
But any such calculations would have to take into account sexual preferences, and even if the spread was rapid, exactly how many generations would be required for the dark gene to have been completely lost?
If sexual prefernce dictated a rapid spread, then if the change took place in Africa, then Africans would logically be white, therefore logic says that the change took place after they left Africa or that they were white before hand and black skin came later.
Either argument appears not to fit a short time scale. Another nail in the OOA scenario as I see it.

[Beagle]

I was originally schooled in Mendellian genetics Dig. Your points are valid as far as I know. I'm currently studying what both Hawks and Bednarik are saying about rapid evolution, population size, and introgression over the last 100,000 yrs.

I really think that's where it's at.

[Digit]

Keep us upto date with your views on this will you please?

[Minimalist]

I see no problem a with a gentic change resulting in a change in colour

So...if white happens because it is too cold and black happens because it is too hot.....what does yellow result from? "Just right"... a la Goldilocks?

The problem with discussions like this is the current emphasis on poltical correctness which instantly turns them into a furor but someone really needs to start thinking this whole idea through.... and I do mean "thinking."

[Beagle]

Sure - but I'm a slow learner.

[Digit]

I can't see that any pigment change occurred because of temperature/lack of sunlight etc Min. Survival rates/breeding advantages/sexual preferences may have worked to select them, but not initiate them.

[rich]

Ish - leave the Trappist Monks alone - their sole purpose on this earth was to make fine ale!

Besides the color difference - I thought I remembered someone saying there was a bone structure difference in the skulls - higher cheeckbones, rounder, and a couple other things that made it possible to detect what race the skeletons were from. Yes - no? If so - it would make it even more of a question.

[Minimalist]

Absolutely right, Rich. And that seems even less explicable in the terms of "environmental-response evolution," (to coin a phrase.)

[john]

All -

A couple of references to surface area vs. body mass theory.............

http://www.johnhawks.net/weblog/fossils ... ass_2005.w

http://prizedwriting.ucdavis.edu/past/1 ... 8/eng.html

All good & logical so far, as humans, like any other animal

Are a furnace burning energy;

The highest survival rates belong

To those with the most efficient furnace.

Now, to a seemingly utterly disparate point,

Hummingbirds in the Western Hemisphere, despite their

Radical differences in appearance, are genetically separated

Only by a couple of secondary/tertiary sexual gene markers.

Therefore, my first question would be whether

Skin color is genetically tied to the efficiency of the furnace,

Or to a secondary sexual characteristic.


hoka hey


john

[dannan14]

Dark skin can cause Vitamin D deficiencies in northern latitudes. Dark skin is also more easily damaged in the cold than light skin is. Likewise light skin is far more susceptible to UV burns which can also destroy folate. Lack of folate can lead to a whole lot of reproductive problems and fetal development problems.

The Aborigines have been in Australia for a very long time. Maybe the peoples of south Asia and Central and northern South America just need more time to adapt?

[Minimalist]

Likewise light skin is far more susceptible to UV burns which can also destroy folate.

So why are the Boers not dead? 400 years is a long time to have a sunburn.

[dannan14]

So it was hard to pick just two out of the list of seven words i chose one for its cultural effect in America since it is probably the most recognized Spanish word by non Spanish speakers here. The other i chose because it shows how slang can preserve the past.

AQ'WA meaning 'water' is found in Nilo-Saharan (e.g. in Nyimang kwe, 'water', and Kwama uuku, 'water'), Afro-Asiatic (Janjero ak(k)a, 'water'), Altaic (Japanese aka, 'bilge water', Ainu wakka, 'water'), Amerind (Allentiac aka, 'water', Culino yaku, 'water' and waka, 'river', Koraveka ako, 'drink', Fulnio waka, 'lake') and Indo-European (Latin aqua, 'water').

PUTI meaning 'vulva' has been shown to exist in Niger-Kordofanian (as in the Malinke word butu, 'vuvla'), Nilo-Saharan (Gao buti, 'vulva'), Afro-Asiatic (Hebrew pot, 'Vulva', in the Chadic language Jegu paate, 'vulva'), Uralic-Yukaghir (Ostyak puti, 'rectum'), Dravidian (Tulu puti, 'vulva'), Austric (Ami puki, 'vulva'), Amerind (Yamana puta, 'hole', Guahibo petu, 'vagina', Jaricuma poita, 'vagina') and Indo-European (Old French pute - modern putain - 'whore').

From 'The Lost Civilizations of the Stone Age'

[rich]

Hmm - so each of the "races" could also be viewed as a subset of the species - much as with dogs - terriers, collies, sheppards, dalmatians, etc.
Wonder which is actually the oldest of the sub-species of human and which the youngest. Do they know?

[dannan14]

Likewise light skin is far more susceptible to UV burns which can also destroy folate.

So why are the Boers not dead? 400 years is a long time to have a sunburn.

My guess is the negative effect are marginal, but just enough to encourage long term adaptation. 400 years probably isn't long enough.