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East-African, want to know more on my ancestors

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  • #16
    Cacio: Are you certain that the skin colour of the first homo sapiens sapiens to leave Africa was dark? I understand that the first wave likely came out of the Ethiopia/Horn of Africa area and, as such, I would expect the colour of the first people to have been the same as modern people living there. Wouldn't the emigrants' skin have become darker or lighter depending on their UV exposure at different points on the earth?

    John

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    • #17
      John:

      I think you are right that there is no sure proof yet of the issue. Early humans did not have fur and lived in the savanna, so the only way to survive would have been to have lots of melanin against the sun. And people living in the horn of Africa have dark skin (though with recent Arabic admixture in the north).

      I think I saw a recent paper that claims to have identified some mutations responsible for pale skin. Apparently East Asians and Europeans have different mutations, suggesting that the process happened independently. As you say, skin color is subject to strong natural selection, so it tends to change depending on the cirumstances.

      Chimps have white skin, so presumably humans became dark when they shed their fur.

      cacio

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      • #18
        I did not know that Chimps had white skin. So I did a little further research and it appears that all human ancestors were likely light-skinned, but hairy, and with few sweat glands. As a result of climate change, it became important to have more sweat glands and less hair. So our ancestors became less hairy and more sweaty and sunburned. It then apparently became advantageous to have dark skin and have about 2 million sweat glands all over one's body (before the sweat glands were located mostly in the hands and feet). After leaving the Horn of Africa, it became advantageous for some groups to have darker skin because of UV rays, and for others to have lighter skin to avoid vitamin deficiencies.

        Our ancestors therefore appear to have changed in skin color several times in the course of adapting to their environment. Skin color has no predictive value in assessing phylogenetic relationships between people.

        I have attached a link to the abstract of the article dealing with this issue:

        http://www.calacademy.org/research/a...files/skin.pdf

        John

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        • #19
          Originally posted by cacio
          Arimas:

          that's interesting- I didn't know of this similarity btw southern Indians and some Ethiopians. Typical southern Indian mtdna would be M(xM1) or R, and there doesn't seem to be much in the studied sample (there is some more in Yemen). Typical southern Indian Y would be H and L (in addition to the Aryan R1a), with a sprinkling of C and F*. Again, none found in Ethiopia. So there's probably not much. I wonder how much of the similarity is due to skin color. Skin color obviously depends a lot on latitude. The early modern humans that left Africa were dark. Those who arrived and settled in southern India remained so- given that they lived near the equator. Only those who ventured north of India eventually had mutations that made them pale.

          cacio
          The Afar language belongs to Couchitic language and the Afars are a people that live in the Horn across many countries (I am sure about Djibouti, Ethiopia, Erithrea but they could also live in South Sudan etc)

          Here is what they look like: some of them look like Somali but they have at least two other types (different that those who look kind of like Somali).
          -one group is very dark with very high check bones (maybe a difference with Indians) but they have straight soft hair...dark skin with straight hair people exist among Somali but the skin is less dark usually.
          Anyway, the way I learned about the resemblance was: I had friends from Mauritius and as you may know the majority of Mauricians have Indian blood. Well, one these friends was so sure that some of the students she met in the campus were from her country...until she saw me talking to them and let me tell you she couldn't believe they were not from Mauritius.

          to be continued...(have to go to work)

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          • #20
            I tried to edit my last post because of the bad English but couldn't do it and wondering if this site let people edit their posts...anyway, English is my 4th language so I think I can be forgiven some mistakes

            About the Afars, I have so many anecdotes of people confusing Afars with Indians. One example of that is when I was introduced to a friend of my brother as someone from India and all the time we talked was told he doesn't understand our languages... Somali or French (I think I had to use my poor English at the time). But everything was a big joke, they all started laughing and told me that the guy wasn't Indian but an Afar from my country. Another time, we were given an Indian restaurant cards and the cab driver added "you're Indian I suppose" (well maybe there weren't that many Indians in the small town of Northern France)...we looked at each others and said no and then I finally realized that if I didn't look that Indian, my 2 Afars friends were. One dark with straight hair and the other with an Arab complexion with straight long hair (probably from the other type of Afars I wanted to mention...look like they are mixed with Arabs or Indians).

            I definitely think the Horn of Africa is a great place to learn about the different human tribes...One thing that always fascinated me in the Somali case is our differences in the same family: having a lighter skin is not for one tribe or family. Some people are dark but if you meet their own brother or sister (with same dad and mom), you may think the later one is mixed or coming from another country.


            Arimas

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            • #21
              Arimas:

              it seems the Afar would be an interesting population to study. From what you say, it seems that they are an admixture of Arabic and African chromosomes, like the Northern Ethiopians (like the Amharas). But who knows.

              As you point out, since none of the relevant genes determining appearance is on the Y chromosome, you may have all kinds of mixtures within the same family. (In my family for instance, some have blond and some have darker hair).

              cacio

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              • #22
                John:

                very interesting article. The ones I mentioned (about the different paleness genes in European and in Asian) can be found at:

                http://www.ncbi.nlm.nih.gov/entrez/q..._uids=16977434

                cacio

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                • #23
                  Originally posted by cacio
                  Arimas:

                  it seems the Afar would be an interesting population to study. From what you say, it seems that they are an admixture of Arabic and African chromosomes, like the Northern Ethiopians (like the Amharas). But who knows.

                  As you point out, since none of the relevant genes determining appearance is on the Y chromosome, you may have all kinds of mixtures within the same family. (In my family for instance, some have blond and some have darker hair).

                  cacio

                  The Arabic admixture is probably not that high and nothing like in the Amharas that I have seen in Addis-Abeba: even their language is derived from Gueze, a south Arabian old language.
                  I always found resemblance with Southern Indians strange but Afars are an old people, not prompt to live in cities, farmers or nomades but very attached to their roots. They are endogamous (marry among themselves).
                  If you find anything about their haplogroup, let me know. I was thinking maybe it is not about the admixture they have, wouldn't it be possible these Dark Indians are from East-Africa or is the Indo-European theory still good.

                  Maybe it is just the coincidence of having dark not very tall people with soft hair that reminds me of Indian and maybe these are features they share with the Southern Indian without being related to them like the way the Bresilian man killed by British police officers in the summer 2005 shared features with Arabs and Pakistanis.


                  Arimas

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