Black People : Gene mutation might be clue to Europeans' white skin

Discussion in 'Black People Open Forum' started by toylin, Dec 18, 2005.

  1. toylin

    toylin Well-Known Member MEMBER

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    from the Detroit News....

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    By William Hathaway / The Hartford Courant

    December 17, 2005

    The skin color of Europeans might have turned white after their ancestors migrated from Africa because of a single mutation among the 3 billion genetic "letters" that make up the human genome, scientists reported this week.

    The mutation explains part of the lingering mystery of how human skin colors evolved during the last 50,000 years as modern humans migrated across the world after leaving Africa, according to research published Friday in the journal Science.

    "This really calls into question our ideas about race," said Mark Shriver, professor of anthropology and genetics at Pennsylvania State University and an author of the paper.

    Cancer researchers discovered the mutation in zebra fish while investigating a gene they suspected might play a role in malignant melanoma, a skin cancer. Researchers found that a mutation of a gene called SLC24A5 seemed to explain why golden zebra fish had lighter pigmentation in their stripes than other zebra fish.

    In humans as well as fish, variations in skin color are caused by melanin, or specifically the size and number of pigmentation granules called melanosomes within cells. People of European descent -- and the golden zebra fish -- have few, smaller and lighter granules within skin cells.

    While scores of genes have been identified in development of skin pigmentation, there is still confusion about which ones are most important in humans. So scientists at the Pennsylvania State College of Medicine in Hershey wondered whether the mutation of a single specific gene might account for lighter pigmentation in humans as well as in the zebra fish.

    "When you run into something incredibly interesting, you have an obligation to do the best science you can do," said Dr. Keith Cheng, a cancer researcher at the Penn State Cancer Institute and senior author of the Science paper.

    Cheng and his colleagues found they could produce a darker-striped zebra fish by simply switching the mutated gene in a developing golden zebra fish embryo with an unmutated human version of the SLC24A5 gene.

    The reason the stripes turned dark is in that almost all vertebrates, including humans, the normal version of the gene tends to create dark pigmentation.

    When geneticists from Penn State compared the human variations of the gene contained in DNA data bases, they found that West Africans and East Asians have the same SLC24A5 gene as dark-striped zebra fish. But Europeans and the golden zebra fish have similar mutations of that gene.

    "By default, we are all dark-skinned," said Kenneth K. Kidd of Yale's genetics department. "This type of research is a kind of footprint that can describe how modern humans spread out of African origins and occupied the rest of the world."

    The findings, however, only account for differences in skin color of Europeans.

    Differences in shades of skin color among Africans and East Asians, who also can have light skin, must be the work of other genes, the researchers said.

    But Shriver and Kidd say the work is an example of how a tiny molecular change can create a major difference in something as fundamental as skin color.

    Most scientists believe that mutations that created white skin took hold quickly among small groups of people who migrated to northern Europe with longer winter nights.

    Light skin absorbs more Vitamin D, which is needed to strengthen bones, Kidd said. But black skin is advantageous in hotter climates because it has more resistance to harsh ultraviolet rays of the sun.

    Genetic differences between races tend to be tiny, Kidd said.

    Because modern humans originated in Africa, genetic variation among people of African descent tend to be the greatest of all ethnic groups. That means that a person of African descent and a European can be related more closely genetically than two people of African descent, he said. For example, Ethiopians with dark skin are related more closely genetically to Europeans than to West Africans, he said.

    "That's what we mean when we say that race in a broad sense is not a useful concept," Kidd said. "I can't draw a line between where one race begins and the next one starts."

    Understanding subtle genetic differences between ethnic and other population groups might be important because they might explain different susceptibility to disease or resistance to some drugs, Kidd said.
     
  2. Keita Kenyatta

    Keita Kenyatta going above and beyond PREMIUM MEMBER

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    So, I at last get the opportunity to disagree with a so called scholar, huh? What do I disagree about? The so called fact that "light skin absorbs more vitamin D". Now, maybe the way it was phrased may make it correct but here are the actual facts.

    Black skin manufactures vitamin D after just twenty minutes in the sunlight. White skin does not, which is why you will find that many of the foods that they manufacture are fortified with vitamin D. So I was a little thrown off by his statement, and if I got thrown off then it will be very misleading to those less informed than I am.

    So maybe it DOES "ABSORB VITAMIN D"...IF THAT IS WHAT IT'S THIRSTING FOR. I JUST FOUND IT TO BE VERY MISLEADING.
     
  3. spicybrown

    spicybrown Well-Known Member MEMBER

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    Love The Skin You're In...

    Interesting, Toylin. From what I understand, Europeans have calcified pineal glands, somehow blocking the seepage of melanin to vital organs, and throughout the body. I guess the Europeans who appear Olive-toned, or a reddish tint may have a minimal amount of melanin. Blumenbach (17 century), a German 'philosopher', was one of the first to harp on color-coding, and to make it popular to assign colors, thus beginning the color pyramid we're all too familiar with. If this mutation did take place, it would've had to been over a long period of time. It is plausible, because some African origined people do tend to lighten in the winter months, and darken during the summertime. There are several theories on the issue of race, I have my own idea, yet am still open to other's views. Any feedback family?
     
  4. Isaiah

    Isaiah Well-Known Member MEMBER

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    Very interesting, stuff, Toylin...very interesting...
    This I feel is a lot of nonsense, though... "Because modern humans originated in Africa, genetic variation among people of African descent tend to be the greatest of all ethnic groups. That means that a person of African descent and a European can be related more closely genetically than two people of African descent, he said. For example, Ethiopians with dark skin are related more closely genetically to Europeans than to West Africans, he said"


    Peace!
    Isaiah
     
  5. militant

    militant Well-Known Member MEMBER

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    My brother Isaiah, I agree with you. But on account of my what I know, I will say the WHOLE OF IT IS HOGWASH!! To extrapolate the genes of a fish to man needs a little more work to become valid. this is largely the opinion of mere men looking at the mystery of nature. And they even come short with there attempts. Look at this:
    I mean what is science becoming these days?

    Also note that while there was an attempt to draw a line between races on the basis of a single mutation, there was also an attempt at the age old divide and conqueer like below:
    I mean why not talk about the variations among Europeans? Why do Africans have to be the butt of all "Oh they are so many variations withing Africans, they are more dissimilar than they are similar to us". These dissimilar africans like ethiopians are mixed with Arabs!! Geez the craziness in science today!! How come Oprah, a descendant of West africans, can have similar genes to a Zulu person? I mean this is ludacris!!
     
  6. anAfrican

    anAfrican Well-Known Member MEMBER

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    they'll say anything to distract folks from the thought that the white skin is due to their having kept their all-over body hair, i.e., remained more "animal" longer, much longer because it was cold where they evolved.

    the precursor to homo sapiens evolved all over the planet; it is just so much wetter everywhere else than it is in Africa that "proof" of earlier "civilization" in places other than Africa is hard to find ... unless one wants to deforest a whole bunch of this planet. also, a lot of places are underwater due to the ocean levels rising as a result of the recession of the ice ages; early man would have built much along the coast as it was an ideal location due to fishing and transportation.

    i wonder how close angkor vat, machu pichu, the nazca lines and the pyramids are in terms of age and construction techniques? i wonder if the age differences would support the migration theory? or might there have been someone around when the migration got there?

    but who's to know for sure? what with their known tactic of "revisionist history", how can anyone be sure of anything that has been "learned" from anything they've ever done?

    personally, i "like" the idea that those people indigenous to the north atlantic are white because their skin was "protected" from the cold for much longer than those of us that are indigenous to the "living" earth. further, that, because of this longer retention of their "animal nature", and their seperation from the living earth, these folks just can't see the life that they have consistently trashed since they started invading the world.

    but, hey!, "who am i to say?"; i've not been much of a party to the white established educational system, so i don't have the benefit of the "education" one could receive from the text books that they developed. who's to say which bits of "revisionist historical records" are accurate? i find it all as plain as the nose on the sphinx!

    what was that line? "to acheive true wisdom, one must first start by doubting everything" or something like that.
     
  7. kemetkind

    kemetkind Well-Known Member MEMBER

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    The article didn't go into the science too much but the background behind why genetic variations are greater amongst Africans goes like this: Africa was origination of all, and humans spent more time in Africa than we did anywhere else, thus African genetics have had more TIME to evolve, change, mutate, recombine than other populations in the world. It was relatively recent - on the scale of homo sapien - that some left Africa so there has not been the equivalent time (and isolation) to develop variation (at least specific to populations).

    The greatest genetic variation (+85%) is found WITHIN any given population -so you're correct they could have just as easily talked about two Swedes being as different genetically as a Swede and an Ghanian.

    It's not only Africans who have mixed with europeans or Arabs that demonstrate this varied genetic variation - for instance sickle cell trait is a west african or south asian thing but doesn't occur in southern africans.

    On looking at fish genes before going to humans It's a pretty common practice to perform research first on lower animals before targeting more expensive mammals like rats, cats and dogs. Many of the drugs are researched this way before human testing is ever involved.

    The article pretty much falls in line with accepted science on the topic. The vast majority of any human genetic variation is due to mutation and possibly some selection based on that mutation....no matter if we're talking about some white people's skin or some black people's resistance to malaria.
     
  8. Jflex!

    Jflex! Well-Known Member MEMBER

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    When you remove all the nutrients and vitamins and everything useful & healthy from whole-wheat bread, brown-rice, or brown sugar, you end-up with...white folks.
     
  9. Therious

    Therious Banned MEMBER

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    Its funny white scientists are saying this now, afte Afrikan scientists have claimed this theory long ago. theyre labeled as psuedo.
     
  10. Deepvoice

    Deepvoice Well-Known Member MEMBER

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    I just don't get it.
     
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