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East Africans may have up to a quarter of Asian and European DNA, says report
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[QUOTE]Originally posted by Ish Gebor: [QB] [QUOTE]Originally posted by the lioness,: [qb] ^ All you are doing is showing haplogroups, some of which are indigenous and some foreign Some of the divergence spoken of in the book are of a variety "alleles", alternative forms of the same gene In Eurasia you don't find the same degree of variety of the same gene [/qb][/QUOTE]Ironically, Brenna Henn, in this 2014 interview on population genetics and population structure, considering African populations. “African populations have the most genetic diversity in the world,” Henn said.“If you compared people from the Kalahari Desert to people from Mali, they’d be as different from each other [genetically] as Italians and Chinese people.” Why are other populations of humans so much less genetically varied than Africans? The answer, Henn explains, lies in our ancestors’ history; the groups of people that migrated out of Africa and spread throughout other continents were smaller subsets of that original, genetically diverse population. [b]"AND WITHIN EACH OF THESE GROUPS THERE IS AN AMAZING AMOUNT OF DIVERSITY,[...] THE DIVERSITY IS INDIGNIOUS TO AFRICAN POPULATIONS":[/b] Tracing Family Trees, And Human History, With Genetics https://www.youtube.com/watch?v=Pjf0qKdzmrc [QUOTE] Fluctuation in population size might be a mark of the out of Africa group because migration and challenges of adapting to new environments subject the population to both influences of drift and inbreeding. Cases of low census size and a larger inbreeding effective size are known in mammalian populations and attributed to recent population reductions [44]. Although the difference between the current and expected census for Australians was not statistically significant it still indicates an interesting feature of this isolated group. It is not clear why Australia was colonized with a higher population size than the populations that colonized other regions. Henn et al., [45] contemplated this in the light of lineage specific acceleration. Our findings, however, indicate that the population of Australia may have maintained a legacy of high Ne originally carried by the ancestral group that left Africa and seen in the number of haplotypes that survived in their gene pool. This may suggest that both census and effective size of the group that made it to Australia was large enough to counteract the effect of drift and permit survival of relics of these original haplotypes. [b]It is not only genetic data that lends support to an east African origin of humans but the unparalleled ethnic and linguistic diversity that remains one of the highest worldwide. Interestingly the two most ancestral sequences in the NJ tree figure refer to Nubian individuals. Nubia is currently identified with one of the most ancient human settlements, the Say culture. Recently, a related compound associated with a lithic middle Stone Agindustry was discovered in Dhofar Oman and taken as an evidence of human migration out of Africa through an Arabian route [46]. Overall, the various genetic markers used in the current analysis support the observation of human effective population size larger than previously estimated, and emphasize the importance of sampling populations of putative deep ancestry.[/b] [/QUOTE][...] [QUOTE] [i][b]According to the current data East Africa is home to nearly 2/3 of the world genetic diversity independent of sampling effect. Similar figure have been suggested for sub-Saharan Africa populations [1]. [/b] The antiquity of the east African gene pool could be viewed not only from the perspective of the amount of genetic diversity endowed within it but also by signals of uni-modal distribution in their mitochondrial DNA (Hassan et al., unpublished) usually taken as an indication of populations that have passed through ‘‘recent’’ demographic expansion [33], although in this case, may in fact be considered a sign of extended shared history of in situ evolution where alleles are exchanged between neighboring demes [34].[/i] [IMG]http://oi58.tinypic.com/2w567ut.jpg[/IMG] [list] [*]Figure S1 Neighbor joining (NJ). NJ tree of the world populations based on MT-CO2 sequences. The evolutionary relationship of 171 sequences and evolutionary history was inferred using the Neighbor-Joining method. The optimal tree with the sum of branch length = 0.20401570 is shown. The evolutionary distances were computed using the Maximum Composite Likelihood method and are in the units of the number of base substitutions per site. Codon positions included were 1st+2nd+3rd+Noncoding. All positions containing gaps and missing data were eliminated from the dataset. There were a total of 543 positions in the final dataset. Phylogenetic analyses were conducted in MEGA4. Red dots: east Africa, Blue: Africa, Green: Asia, Yellow: Australia, Pink: Europe and gray: America. (TIF) [/list] [IMG]http://oi59.tinypic.com/sl44ud.jpg[/IMG] [list] [*]Figure S2 Multidimensional Scaling Plot (MDS). The 2nd and 3rd coordinates of an MDS plot of 848 nuclear microsatellite loci from 469 individuals of 24 world populations. MDS uses pairwise IBS data based on the 848 loci generated by PLINK software and plotted using R version 2.15.0. [b]The figure, besides a separate clustering of east Africans, indicates the substantial contribution of Africans and east Africans to the founding of populations of Europe and Asia.[/b] (TIF) [/list] [IMG]http://oi62.tinypic.com/s5v8uu.jpg[/IMG] [list] [*]Figure S3 Multidimensional Scaling Plot (MDS). The 3rd and 4th coordinates of an MDS plot of 848 Microsatellite loci, across the human genome in 469 individuals from 24 populations from Africa, Asia and Europe. MDS uses pairwise IBS data based on the 848 loci generated by PLINK software and plotted using R version 2.15.0. [b]The central position of east Africans and some other Africans emphasizes the founding role of east African gene pool and the disparate alignment on coordinates along which the world populations were founded including populations of Aftica aligning along the 4th dimension.[/b] (TIF) [/list] [i]Figure 4. Multidimensional Scaling Plot (MDS). A. First and second coordinates of an MDS plot of 848 Microsatellite Marshfield data set across the human genome for 24 populations from Africa, Asia and Europe. MDS plot was constructed from pairwise differences FST generated by Arlequin program (Table S3). B. First and second coordinates of an MDS plot of 848 Microsatellite loci, across the human genome in 469 individuals from 24 populations from Africa, Asia and Europe. [b]MDS uses pairwise IBS data based on the 848 loci generated by PLINK software and plotted using R version 2.15.0. East Africans cluster to the left of the plot, while Beja (red cluster in the middle), assumes intermediate position.[/b] doi:10.1371/journal.pone.0097674.g004[/i] [list] [*]Figure S4 Multidimensional Scaling Plot (MDS). First and second coordinates of an MDS plot based on MT-CO2 data set constructed from pairwise differences FST generated by Arlequin v3.11. Population code as follows: Nara: Nar, Kunama (Kun), Hidarb (Hid), Afar (Afa), Saho (Sah), Bilen (Bil), Tigre (Tgr), Tigrigna (Tig), Rashaida (Rsh), Nilotics (Nil), Beja (Bej), Ethiopians(Eth), Egyptians (Egy), Moroccans (Mor), Southern Africans (Sth), Pygmy (Pyg), Saudi Arabia (Sdi), Asia (Asi), Europe (Eur), Native Americans (NA), Australians (Ast), Nubians (Nub), Nuba (Nba) (TIF) [/list] [/QUOTE]--Jibril Hirbo, Sara Tishkoff et al. The Episode of Genetic Drift Defining the Migration of Humans out of Africa Is Derived from a Large East African Population Size PLoS One. 2014; 9(5): e97674. Published online 2014 May 20. doi: 10.1371/journal.pone.0097674 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4028218/pdf/pone.0097674.pdf [/QB][/QUOTE]
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