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Ancient Egyptian DNA from 1300BC to 426 AD
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[QUOTE]Originally posted by Cass/: [QB] @ Xyman I don't think all genetic/phenotypic traits originated in East Africa, but the majority of them. Why? More people = more mutations; East Africa throughout the Miocene and Pleistocene (until around 20 kya) had the largest human population-size. Afrocentrists/OOA theorists argue the fact East Africans (or more broadly Sub-Saharan Africans) have the most genetic diversity is because humans originated there. However, it can alternatively be explained by larger population size, without humans originating there: [QUOTE][b]Higher Genetic Variation in Africa[/b] The rapid development of DNA markers since the 1980s has led to the discovery that there is more genetic diversity in sub-Saharan Africa than in other geographic regions of the world (Relethford, 2001, 2008; Jobling et al., 2004; Tishkoff and Gonder, 2007). This observation was not seen in earlier genetic studies that relied on red blood cell polymorphisms, most likely because of ascertainment bias where most genetic variants were looked for, and detected, in European samples. The consistent higher levels of DNA diversity in African samples suggest that it is a function of the primarily African origin of our species. Again, multiple demographic histories can affect differences in genetic diversity, which is a function (for neutral markers) of mutation, population size, and elapsed time. Higher levels of African diversity are expected under a model where modern humans existed for many millennia before dispersing out of Africa. The longer a population exists, the more mutations are accumulated, and the higher the level of genetic diversity. Under a model of an out-of-Africa bottleneck, diversity would be initially reduced (because of founder effect) in the non- African populations. A bottleneck also fits the observation that the DNA diversity outside of Africa is most often a subset of the diversity found within Africa (Tishkoff and Gonder, 2007), showing that a number of alleles were lost due to genetic drift during a bottleneck. [b]Another possibility is that Africa has had a larger effective population size for most of the time span of modern humans, and as such has experienced less genetic drift than smaller populations outside of Africa (Relethford and Harpending, 1994; Relethford and Jorde, 1999). A larger effective population size could simply reflect greater population density and numbers of populations, consistent with ecological and archaeological inference (Eller et al., 2004)[/b].[/QUOTE]- Relethford, 2013 As I said in my own thread a few days ago: there's nothing falsifying a non-African origin of humans as long as it is recognised East Africa (or broadly Sub-Saharan Africa) had the largest population throughout nearly all of human evolution. This upsets some dogmatic/political Out-of-Africa proponents - there is an alternative model to them that explains the genetic facts. [/QB][/QUOTE]
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