here’s my question

ok. so, we’re all out of africa, right?

and one of the reasons for thinking this is ’cause there’s greater genetic diversity in african populations than non-africans suggesting, from what i understand, a population bottleneck in those groups who left africa and greater genetic drift back in the african population. (amiright?)

but, mutation rates are higher in hot climates than cold (edit: see better link re. mammals here), so couldn’t the greater genetic diversity in africans simply be a product of that effect?

see what i’m sayin’/askin’?

(note: comments do not require an email. full genome sequence optional.)

9 Comments

  1. We are partly all out of Africa (don’t forget the influx of Neanderthal genes).

    I think well said in that link you gave. Non-Africans have slower rate of genetic drift probably due to the frequent migration of different living environments. I suspect that probably sub-Sahara Africans were confined in a similar natural habitat longer than others who went out of Africa, that could also probably contribute to the fact that they have greater genetic diversity from natural selection?

    Just saying..

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  2. At the link you gave, it’s plants that are evolving/mutating faster. Hotter weather wouldn’t have much effect on humans or most other animals, since their temperatures are highly regulated. It could seem to have an effect on reptiles and amphibians though, and Africa is certainly known for its snakes.

    What I don’t understand is that even mutating faster, it’s implied that the mutations are useful, i.e. there are enough different environments for the plants to evolve into.

    I read some research years ago (but have been unable to find it since) correlating the density of languages in a given area with its rainfall level. West Africa had the most languages and most rainfall. I’d like to see a post from you on that.

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  3. @the slitty eye – well, what i was thinking is, if the large amount of genetic variation in sub-saharan africans is due to them living in a hot climate, then does that really tell us anything about them being decended from the oldest population on the planet? i mean, can we really use their greater genetic variation as a clue to everyone being out of africa if their genetic variation is simply a product of their hot environment. see?

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  4. @dennis – “At the link you gave, it’s plants that are evolving/mutating faster. Hotter weather wouldn’t have much effect on humans or most other animals, since their temperatures are highly regulated.”

    oh, my bad. i was tipsy in a hurry when i posted that last night so i didn’t look closely at that page.

    the fast mutation rates in hot climates happen in mammals, too:

    Mammals Evolve Faster in the Tropics, Confounding Scientists

    @dennis – “I’d like to see a post from you on that.”

    i’d like to see that, too. (~_^) i haven’t heard about that before — i’ll have to read up on it. i’m heading off on vacation shortly, so it’ll have to wait ’til i get back, i’m afraid.

    Reply

  5. Ok so let me try to understand this since, despite my fantastically made up calculation from a previous post, I’ve really no idea about any of this stuff.

    Are they claiming greater diversity AMONGST Africans is evidence that WE are all descended from the same stock?

    Reply

  6. Another reason that most scientists think that humans originated in Africa is that our closest living relatives – chimpanzees and gorillas – are also found on that continent.

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  7. @aoirthoir – “Are they claiming greater diversity AMONGST Africans is evidence that WE are all descended from the same stock?”

    yeah. something along the lines of (and i’m prolly getting this not-quite-right) because there’s more genetic diversity in sub-saharan africans, and less in eurasians, that shows that our ancestors went through a population bottleneck (i.e. a small group or groups left africa and we eurasians are all decended from there), while the ancestors of sub-saharan africans didn’t go through that bottleneck, so they have more genetic diversity.

    you’re prolly better off reading the wiki-p page about this since i am cr*p at explaining it.

    but then my question is, what if the genetic diversity in sub-saharan africans is due to the more rapid evolution in hot climates versus the fact that they didn’t go through a population bottleneck? where does the out of africa theory stand then? are there any paleoanthropologists thinking along these lines? inquiring minds want to know!

    Reply

  8. @joe – “Another reason that most scientists think that humans originated in Africa is that our closest living relatives – chimpanzees and gorillas – are also found on that continent.”

    sure. i was just questioning this one piece of evidence. (^_^)

    Reply

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