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The different hair styles of the Ancient Egyptians
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[QUOTE]Originally posted by Amun-Ra The Ultimate: [QB] [QUOTE]Originally posted by the lioness: [URL=http://www.dnatribes.com/dnatribes-snp-admixture-2012-03-12.pdf]DNATribes admixture by population[/URL] [IMG]http://i1079.photobucket.com/albums/w513/Amunratheultimate/Misc/21RegionsAdmixture-Africanpart2.jpg[/IMG] [IMG]http://picturestack.com/747/572/Mv4Picture3U9g.png[/IMG] you're right that the blue chart has some out of Africa world populations. But it's mistaken to say that the blue chart is more accurate or the orange chart is more accurate. They are not necessarily contradicting one another. [/QUOTE]I'm not the one who said that first. The 21 World Region are said to "provide the [b]most detailed[/b] and [b]representative[/b] comparison of your DNA to world population structure. The difference lay imo in how those regions were determined. The orange 7 continents Admixture regions are determined by geography. The blue 21 regions Admixture regions are derived by DNA Tribes proprietary statistical analysis (of the DNA SNPs value the have in their database). Maybe the 7 continents admixture regions are also derived with some DNA Tribes proprietary statistical analysis too, but I don't think so. The 21 regions Admixture regions tend to segregate more between ethnic groups since it's how they were derived (by mathematically subdividing ethnic groups by common SNP value and make a region out of them). [QUOTE] The two charts are testing some of the same regions but not all and this can be confusing. What we notice is in the orange chart they tested for Middle Eastern and came up with 54.5 % In the blue region chart they only tested for Arabian not the whole of the Middle East and came up with 7.9% Arabian. [/QUOTE]You're mistaken about that, they've tested against all the world population groups (obviously). The only difference is the 21 Region blue table subdivide Middle East into smaller units which at least contain Arabian and North Africa (also boundaries can be changed). I think the preceding Middle East continental zone included some part of the Horn of Africa. The 21 region blue chart hits Arabian but North Africa value is nil (see "Other" line). It's because the 21 region blue table is more precise and tend to segregate regional ethnic groupings more. The Middle Eastern region in the 7 Continental orange table seems to recoup some region of Horn Africa. At least, that would be a possible explanation for it. [QUOTE] This means they majority Middle Eastern ancestry on average but it is not mainly Arabian. [/QUOTE]All the contrary. The Somalian people they sampled seems to be mainly native Somalian ancestry with some Arabian admixture but no North African one (or other middle eastern regions). Again, it seems they have taken people in their sample which are more admixed as representative of the whole Somalian subgroup. [QUOTE] The Somalis, like the Ethiopian groups, show almost no impact from the Bantu expansion. [/QUOTE]It doesn't mean anything. You can always subdivide (or combine) people from the same ethnic family. For example, you can subdivide the common Bantu family into Zulu and Shona. Then say Zulu don't have Shona DNA. You can subdivide Europeans into Iberian and Northwest Europeans. You can subdivide the African family into Bantu, Horn Africans, Tropical West Africans etc. All those people share common ancestry (aka common SNP values) as well as having some common ancestry of their own (after the separation into sub-groupings and being separated by geographical distance). Here we can see that all African groups (Central Africans, Horn Africans, Southern Africans, West Africans, African Great Lakes Africans) share common ancestors and are relatively close to each other in term of genetic distance. They all share common SNP values. They are all part of a group called "Sub-Saharan Africans" by DNA Tribes. [IMG]http://i1079.photobucket.com/albums/w513/Amunratheultimate/Misc/EucledianDistanceTreeofGeneticWorldRegions.jpg[/IMG] As we can see, it's always a "game" of subdividing and regrouping ethnic groups together. All African group share common SNP value distinct from all other people on earth, at the same time some SNP value are more common in certain African sub-regions and can thus be further subdivided into smaller unit like Southern Africans or Tropical West Africans. Same thing with the Human family in general each meeting point in the above table represent common ancestry (usually). That is common SNP value. Human are one large family with mostly the same SNP values (99%+) but some regions have some SNP value more common in their particular region so we can subdivided them into smaller, and smaller units. Even Tropical West African, I'm sure, could be subdivided into smaller units maybe Yoruba, Igbo, Ewe, etc. with SNP value more common in their region. At the extreme we can isolate you and your family (mother, father, brother, cousins) SNP values from other families. [b]So it's always a "game" of subdividing and regrouping ethnic groups together. The map above does the 2 things. (Meeting lines -nodes- are common ancestry, branches are subdivisions of those common ancestry).[/b] As a side note, such genetic distance tree are very sensible to extreme values. It's one of the reasons it's really important to NOT choose admixed people in their sample while deriving such tree. To have people who truly form a native ethnic groups. Especially if you're interested in analyzing ancestral/past relationship between people. Because only 1 or 2 individuals very much admixed in modern time (with foreign SNP values) can change the genetic distance in a big way. The degree of admixture (or purity) of the sampled chosen for each population must be kept in mind when analyzing a genetic tree. [/QB][/QUOTE]
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