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Thread: Population specific adaptations

  1. #1 Population specific adaptations 
    Administrator KALSTER's Avatar
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    I am curious, have there been any studies to determine if different races have some abilities that stem from their DNA make-up? I mean, are some races better at some things than other races are as a result of their DNA make-up? This is not from a racist perspective. Black people, as an example, have more melanin in their skin, so less vitamin D is produced. I am thinking that some races would be able to do some things better than others as a result of where they differentiated from the rest. There are some fairly large differences in appearance.


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    Forum Cosmic Wizard spuriousmonkey's Avatar
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    i don't know about race. I know about local populations though.

    Tibetans are genetically adapted to live at high altitudes. Unlike for instance other people like for instance in the Andes who moved to higher altitudes more recently.

    These are not physiological effects caused by adaptation to the environment.

    For instance: the birth weight is negatively correlated with the elevation in ALL humans. Except for tibetans. They give birth to babies of normal weight at high altitudes.

    There are more adaptations.


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    Yes, I remember reading about that. My original post was a bit incoherent, sorry. What about general appearance? Skin tone, eye color, etc? Are these mainly as a result of adaptation to a specific environment? I know about previous attempts to identify differences being tainted by racist preconceptions, like smaller brain size in Africans and such nonsense. But there must be some advantages races have over each other in some departments?
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    The people in western Kenya called the Kalenjin are exceptionally good at running. They win just about every marathon and olympic event :P Apparently they are genetically predisposed to efficient oxygen consumption and slender bodies.
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    Forum Cosmic Wizard spuriousmonkey's Avatar
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    Quote Originally Posted by rancidchickn
    The people in western Kenya called the Kalenjin are exceptionally good at running. They win just about every marathon and olympic event :P Apparently they are genetically predisposed to efficient oxygen consumption and slender bodies.
    Wasn't it mostly the slender shape of the foot and ankle instead of the whole body? Because the slender body type itself isn't that uncommon. I saw a tv program once a long time ago, but can't really remember the details.
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    Quote Originally Posted by KALSTER
    Yes, I remember reading about that. My original post was a bit incoherent, sorry. What about general appearance? Skin tone, eye color, etc? Are these mainly as a result of adaptation to a specific environment? I know about previous attempts to identify differences being tainted by racist preconceptions, like smaller brain size in Africans and such nonsense. But there must be some advantages races have over each other in some departments?
    In order to prevent people from considering this thread, or posts on it, to be racist, it is best not to use the word 'race'. Even in the biological sense of 'race' (an incipient sub-species) there is no human population that corresponds to the definition.

    It would be best to speak of populations or groups. This is not just politically sensitive, but, given the incorrigible human propensity for reproducing no matter what the social, cultural or genetic barriers, an empirical truth. As has previously been observed, just about everybody in Europe, Asia, North Africa, and most of North America is, amongst other things, descended from Genghis Khan. I say amongst other things because most of us are also descended from Julius Caesar, the Indian Emperor Ashoka and many many people who aren't famous. It's just a fact of human genetic history, whether or not you seem morphologically darker, to have higher cheekbones, to possess what is called an epicanthic fold, to be endomorphic or whatever other criterion regarding appearance you wish to use: you are still descended from Temujin of the Kurultai and the others named here.

    Different population groups, on the other hand, may share non-obvious, genetically mediated, characteristics - like lactose tolerance, or malaria resistance through sickle-cell trait and so on.

    Whichever way you investigate it, though, neither black nor white are 'races'. Describing people as black or white is almost entirely a cultural construct that has little or no correspondence with the underlying genetic similarities/differences betwen people.

    Richard Dawkins, in "The Ancestor's Tale", points out that these superficial differences in features may represent a form of sexual selection.

    Steve Olsen wrote "Mapping Human History" from which I took (or interpreted) the conceit regarding the descendants of Genghis Khan.

    Hope this helps.

    cheer

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    Thanks for setting me straight! I would not want anyone to misinterpret my intentions with this thread.
    I do not subscribe to the thought than any “population” is superior to another. There are many differences in culture, appearance, religion and physiology that make each population unique and special in there own right. I am merely very much enthralled by the many facets of the human condition, both physically and psychologically.

    So moving on. I think Africans have the “malaria resistance through sickle-cell trait” and Inuit peoples have lactose tolerance, if I’m not mistaken. This is what I am looking for. Others?
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    Forum Cosmic Wizard spuriousmonkey's Avatar
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    I think sickle cell is also common in parts of Asia.
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    Quote Originally Posted by KALSTER
    Thanks for setting me straight! I would not want anyone to misinterpret my intentions with this thread.
    I do not subscribe to the thought than any “population” is superior to another. There are many differences in culture, appearance, religion and physiology that make each population unique and special in there own right. I am merely very much enthralled by the many facets of the human condition, both physically and psychologically.
    That's cool. It's such an emotionally loaded topic that it's as well to get it right.

    Quote Originally Posted by KALSTER
    So moving on. I think Africans have the “malaria resistance through sickle-cell trait” and Inuit peoples have lactose tolerance, if I’m not mistaken. This is what I am looking for. Others?
    Here's where getting it right would help remove misunderstandings.

    1. There is no such group as 'Africans'. The best evdience we have currently seems to show that, as modern humans, we are all Africans. If this seems too simplistic, then consider that the original African population(s) of humans appear to have split into 5 major groups: The Asian/East Asian; the 'Semitic' (it's not a group so much as a group of people loosely described as those who use Semitic languages: Hebrew Arabic etc); the 'Bantu' (again defined in the way 'Semitic' is, but with Bantu languages); the 'forest people' (formerly called pygmies, who are no more 'Black African' than Queen Elizabeth); and the 'bushmen'/'Khoi-San' people (again defined by their use of Khoi or San group languages - the ones with the famous clicks). This means that all modern Europeans or their descendants in North America and the Antipodes, are a conjunct group of people who ancestry, post-Africa, lies in both East Asia and the Middle East. Basically, there is no more such a group as 'African' as there is a language called African.

    2. Certain African populations, usually amongst Bantu-group speakers (who also, as it happens, were the primary source populations for the infamous slave trade, and hence provide some of the genetic roots of modern-day 'African-americans'), have the sickle cell gene which, if inherited from both parents causes the painful and usually fatal sickle cell anaemia, but if present in only one of the chromosomes provides some protection against malaria (but, unfortunately, with side effects: frequent acute and chronic pains in the back, cramps, often increased susceptibility to other attacks on the immune system and so on).

    3. Lactose tolerance is actually in the minority in the world's population. There are only two groups of people with the genetic modifications required that enable them to drink milk, as adults, without discomfort. One of these groups is in Africa (but, surprisingly, not amongst the Masai, despite their dependence upon cattle and cattle products). The other minority group with lactose tolerance is a small group of people we tend to call ‘white Europeans’ – likely to be most on this board, and most English-language users, whence the unquestioned notion that lactose tolerance is the norm!

    4. There are many individual traits that ‘travel’ through populations. They tend to be called haplotypes – a group of genes that travels together in a particular allelic combination. Most of them, alas, tend to act to the detriment of the group concerned – Tay Sachs, Sickle Cell Anaemia and so on are relics of possibly earlier evolutonary changes to survive particular environments (malarial and so on), that are no longer as relevant to survival.

    Another book worth reading, if you are truly interested in this sort of thing, is Jared Diamond’s monumental “Guns, germs and steel”.

    cheer

    shanks
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    Quote Originally Posted by sunshinewarrio
    In order to prevent people from considering this thread, or posts on it, to be racist, it is best not to use the word 'race'. Even in the biological sense of 'race' (an incipient sub-species) there is no human population that corresponds to the definition.
    It is all well and good to say that there is no such thing as race, but as long as there are government or other forms to fill out identifying yourself as belonging to a racial or ethnic group, then there is something called race. Race being, whatever said forms or surveys are measuring.

    And as long as scientists censor themselves from even entertaining the thought of genetic differences between races, then there will only be one acceptable explanation for any statistical differences found, i.e., racial discrimination.
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    Quote Originally Posted by rancidchickn
    The people in western Kenya called the Kalenjin are exceptionally good at running. They win just about every marathon and olympic event :P Apparently they are genetically predisposed to efficient oxygen consumption and slender bodies.
    In general the inhabitants of Ethiopia, Sudan and Kenya dominate world class distant races. In contrast the natives of West Africa (and their Afro-American relatives) dominate the sprint events. The former group have a higher proportion of slow twitch muscles, ideal for enduance events, while the latter have more fast twitch muscles - just the thing for short bursts of energy.
    One is tempted to speculate that whether as hunter or prey, rapid attack or escape, would be beneficial, while in the open lands of East Africa, where wounded prey may be pursued for many hours, then endurance would come to the fore.
    At any rate no one from West Africa has ever won a long distance Olympic or World gold medal, and likewise for sprint events and East Africans.
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    I am sure that a proper study would reveal some very interesting results that would not have the proclaiming of a certain people to be superior as part of it.

    So there are 5 major groups. Bantu, Asian, Semitic, Forrest people and Khoi-San. Apart from language, what peculiarities do each have? Have any studies been done to find possible differences in how they interpret the world? I mean are some better at math, others better at organization and so on? I am fully aware that the specific culture of a person play a huge part in these areas’s, but is there larger trends?
    Again, this is NOT an attempt to substantiate racism!
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    The brain is a physical object, just as muscles and bones are. It would be surprising if muscles and bones would adapt to suit say a forest or savanna environment but brains would not. I think Steven Pinker might be a good source for information on this topic, although it's been some time since I read him.
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    Quote Originally Posted by rancidchickn
    The people in western Kenya called the Kalenjin are exceptionally good at running. They win just about every marathon and olympic event :P Apparently they are genetically predisposed to efficient oxygen consumption and slender bodies.

    That's a good case how 'race' and local adaptions can get confused. some would take Kenyans and apply it to Blacks. We 'assume' differences between races that aren't there. Ask most americans what the tallest race is and they will say 'Blacks' because most basketball players are Black. Wheras in reality the white race is, on average the tallest in the world.

    China is the best example of changes do to local conditions. One race but regionally great variation across the spectrum in height, stockiness, etc.
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    Quote Originally Posted by spuriousmonkey
    i don't know about race. I know about local populations though.

    Tibetans are genetically adapted to live at high altitudes. Unlike for instance other people like for instance in the Andes who moved to higher altitudes more recently.

    These are not physiological effects caused by adaptation to the environment.

    For instance: the birth weight is negatively correlated with the elevation in ALL humans. Except for tibetans. They give birth to babies of normal weight at high altitudes.

    There are more adaptations.
    Cheers! I hadn't known about this. Evidently there is recent research pointing to blood levels of NO in mountain-dwelling Tibetans. In other words, the basis of altitude adaptation in this case (presumably genetic) lies in elevated production of NO, which is thought to facilitate better oxygen delivery.

    The researchers hypothesize that Tibetans have a genetic mutation that allows high NO production. Genetic studies and comparable data on sea-level populations living at high altitude would be needed to test that hypothesis, said Beall.

    During the study, the researchers also recognized another population difference: Tibetan women were found to have higher nitrite and lower nitrate levels than those of Tibetan men, whereas no gender differences were found in sea-level dwellers.

    In this research, blood flow is determined by the length, number and width of the diameter of blood vessels. These numbers are determined partly by NO, which is a dilator of the vessels and prevents high blood pressure, which would result from increased blood flow in restricted blood vessels. NO also helps in the release of oxygen to tissues.

    NO reacts in the blood to produce nitrite, nitrate, nitrosothiol proteins and á-nitrosyl hemoglobin, which can be used as indicators of NO production. To confirm the increases in NO, the researchers subjected the Tibetan samples to sensitive high performance liquid chromatography, where the results verified the 10-fold increase of NO in the blood.
    Primary source:

    http://www.pnas.org/cgi/content/abstract/0707462104v1
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    That is quite interesting. So how much can the O2 content of the atmosphere decline before these Tibetans will start having trouble at sea level? I'm thinking that if our tropical forests get destroyed, we could create a gene therapy to help the rest of us cope.

    What about body types? Some peoples have shorter limbs and longer upper bodies. Is there some advantage to this? Maybe they are simply seen as larger and stronger and might have been preferred as breeding partners. I’ve heard that peoples with longer limbs have them as a result of a long standing dependence on horses. What about hair color and type?
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    Quote Originally Posted by Jellyologist
    Ask most americans what the tallest race is and they will say 'Blacks' because most basketball players are Black. Wheras in reality the white race is, on average the tallest in the world.
    Wouldn't this be because of dietary differences (environmental) rather then genetic differences ?
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    Quote Originally Posted by Cat1981(England)
    Quote Originally Posted by Jellyologist
    Ask most americans what the tallest race is and they will say 'Blacks' because most basketball players are Black. Wheras in reality the white race is, on average the tallest in the world.
    Wouldn't this be because of dietary differences (environmental) rather then genetic differences ?
    I agree with Cat. Even people from stereotypically short ethnic groups, like southeast asians, can grow very tall on a nice fat western diet.
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    And as long as scientists censor themselves from even entertaining the thought of genetic differences between races, then there will only be one acceptable explanation for any statistical differences found, i.e., racial discrimination.
    Well, maybe the reason why scientists don't think in narrowminded categories - as do politicians or the people who elect them - is because the genetic differences between representants of a group you refer to as "race" are way larger than between two groups of people conveniently called "whites" and "blacks".
    This would be equivalent to referring to black or white phenotypes of West Highland Terriers as belonging to different races or calling all black dogs a "race". Interesting concept........black Danes and black West Highland Terriers are of the same race, while a black and a white Dane are referred to as belonging to different races. I don't see the need for "censorship of thought" by scientist, this is just plain and utter BS.
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    Quote Originally Posted by Twaaannnggg
    This would be equivalent to referring to black or white phenotypes of West Highland Terriers as belonging to different races or calling all black dogs a "race". Interesting concept........black Danes and black West Highland Terriers are of the same race, while a black and a white Dane are referred to as belonging to different races. I don't see the need for "censorship of thought" by scientist, this is just plain and utter BS.
    Twang, I’ll make you a bet on the next Kentucky Derby. I predict it will be won by a brown horse. I’ll give you all the white, appaloosa and pinto horses. The hair color shouldn’t matter, right? They are the same race.
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    Quote Originally Posted by paralith
    Quote Originally Posted by Cat1981(England)
    Quote Originally Posted by Jellyologist
    Ask most americans what the tallest race is and they will say 'Blacks' because most basketball players are Black. Wheras in reality the white race is, on average the tallest in the world.
    Wouldn't this be because of dietary differences (environmental) rather then genetic differences ?
    I agree with Cat. Even people from stereotypically short ethnic groups, like southeast asians, can grow very tall on a nice fat western diet.
    Eskimos in the Canada have had western diets for the last couple generations and they are still scraping 5 feet. Good nutrition might lead to some greater average height but genetic differences between groups are still pronounced. The Dutch, the tallest nation in the world, don't have better nutrition than fellow western Europeans.

    If mama is 6' and papa is 6'4" then junior will likely be much taller than if mama is 5' and papa 5'2"....regardless of diet.
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  23. #22  
    Forum Cosmic Wizard spuriousmonkey's Avatar
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    The dutch did go from shortest European people to tallest by means of improved diet, hygiene and medical infrastructure.
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