posted
Found this gem on another site. Special thanks goes to pgbk87 from that site.
Extensive Admixture and Selective Pressure Across the Sahel Belt
quote:Genome-wide studies of African populations have the potential to reveal powerful insights into the evolution of our species, as these diverse populations have been exposed to intense selective pressures imposed by infectious diseases, diet, and environmental factors. Within Africa, the Sahel Belt extensively overlaps the geographical center of several endemic infections such as malaria, trypanosomiasis, meningitis, and hemorrhagic fevers. We screened 2.5 million single nucleotide polymorphisms in 161 individuals from 13 Sahelian populations, which together with published data cover Western, Central, and Eastern Sahel, and include both nomadic and sedentary groups. We confirmed the role of this Belt as a main corridor for human migrations across the continent. Strong admixture was observed in both Central and Eastern Sahelian populations, with North Africans and Near Eastern/Arabians, respectively, but it was inexistent in Western Sahelian populations. Genome-wide local ancestry inference in admixed Sahelian populations revealed several candidate regions that were significantly enriched for non-autochthonous haplotypes, and many showed to be under positive selection. The DARC gene region in Arabs and Nubians was enriched for African ancestry, whereas the RAB3GAP1/LCT/MCM6 region in Oromo, the TAS2R gene family in Fulani, and the ALMS1/NAT8 in Turkana and Samburu were enriched for non-African ancestry. Signals of positive selection varied in terms of geographic amplitude. Some genomic regions were selected across the Belt, the most striking example being the malaria-related DARC gene. Others were Western-specific (oxytocin, calcium, and heart pathways), Eastern-specific (lipid pathways), or even population-restricted (TAS2R genes in Fulani, which may reflect sexual selection).
quote:Originally posted by BlessedbyHorus: Found this gem on another site. Special thanks goes to pgbk87 from that site.
Extensive Admixture and Selective Pressure Across the Sahel Belt
quote:Genome-wide studies of African populations have the potential to reveal powerful insights into the evolution of our species, as these diverse populations have been exposed to intense selective pressures imposed by infectious diseases, diet, and environmental factors. Within Africa, the Sahel Belt extensively overlaps the geographical center of several endemic infections such as malaria, trypanosomiasis, meningitis, and hemorrhagic fevers. We screened 2.5 million single nucleotide polymorphisms in 161 individuals from 13 Sahelian populations, which together with published data cover Western, Central, and Eastern Sahel, and include both nomadic and sedentary groups. We confirmed the role of this Belt as a main corridor for human migrations across the continent. Strong admixture was observed in both Central and Eastern Sahelian populations, with North Africans and Near Eastern/Arabians, respectively, but it was inexistent in Western Sahelian populations. Genome-wide local ancestry inference in admixed Sahelian populations revealed several candidate regions that were significantly enriched for non-autochthonous haplotypes, and many showed to be under positive selection. The DARC gene region in Arabs and Nubians was enriched for African ancestry, whereas the RAB3GAP1/LCT/MCM6 region in Oromo, the TAS2R gene family in Fulani, and the ALMS1/NAT8 in Turkana and Samburu were enriched for non-African ancestry. Signals of positive selection varied in terms of geographic amplitude. Some genomic regions were selected across the Belt, the most striking example being the malaria-related DARC gene. Others were Western-specific (oxytocin, calcium, and heart pathways), Eastern-specific (lipid pathways), or even population-restricted (TAS2R genes in Fulani, which may reflect sexual selection).
More double talk that only covers the last 5-10,000 years of African history, as if that small period of time somehow is the basis of African genetic diversity when humans have been in Africa longer than other place on the planet. So how could NON Africans be a key to African diversity if African genes are 200,000 years old?
What they should be talking about is how all other humans populations evolved from Africans and when the physical split between "African" features and "Non African" features developed.
Of course they are still trying to claim that somehow "North Africa" is somehow separate from Africa and thus the implication of "non Africans" settled there first, again contradicting the fact that Africans have been there longer than anyone.
Case in point:
quote: We applied the RFMix algorithm (Maples et al. 2013), which uses a LD model between markers to infer ancestry for each segment of the genome between a mixture of two putative ancestral panels of haplotypes. We used as ancestral data sets the phased data from the 1,000 Genomes Database, the Italian sample representing southern European ancestry and Gambian or Luhya representing the African ancestry (the first when testing for Fulani and the later when analyzing Central and Eastern Sahelian populations). Italians are a good proxy population for the shared Mediterranean ancestry across southern Europe, North Africa, and the Near East/Arabian Peninsula, which is mixed with the sub-Saharan ancestry across the Sahel (Botigue et al. 2013). For comparison purposes, we assayed the effect of using Great Britain (GB) or Northern Europeans from Utah (CEU) as the non-African parental population in the Oromo data set, although by being derived North European populations, these are not geographically, historically, and anthropologically supported as good proxies for non-African admixture in the Sahel (Table S10). Some differences were observed; for instance, the main block on chromosome 2, in the region of the LCT gene, which has been mainly selected in North Europe, was identified in all three analyses, but the size was different: it was larger when using Italians (133,640,409-137,586,694, totaling 3,946,285 bp) than when using GB (133,346,735-135,210,390 – 1,863,655 bp) or CEU (133,346,735-134,727,858 – 1,381,123 bp). So, an input from a non-European population is confirmed in this region, although we do not know if the driver was LCT or another neighbor gene.
They claim Italians are a good example of ancestral "Eurasian" ancestry in the Sahel as if to claim that ancient "Eurasians" were in the Sahel at the same time and before indigenous African populations. Not only is that false, but it is also propaganda to downplay and provide a diversion from the fact that populations in what is NOW called Italy have always had LARGE waves of migration from Africa, which is true for all of Southern Europe, going back before even the Islamic era. Hence the numerous scenes of dark skinned Etruscans and black Africans in Mediterranean art (Etruscan, Minoan, etc).
But of course, I don't expect these clowns to put history in its proper context. Africans migrating OUT of Africa are the basis of all genetic lineages on earth. That is the only "African" genetic evolution we need to understand. How Africans evolved into all the populations around the world we see today.
Recall that early European 'racists' even called out the African mixture in Southern Europe. But because of their development of ideas of superiority for Europeans, they had to promote this concept of Europeans as "pure and distinct" from all others as opposed to Europeans simply being paleface Africans/South Eurasians (sometimes called Albinos).
quote: In his book, Ripley also proposed the idea that "Africa begins beyond the Pyrenees", as he wrote in page 272 :
" Beyond the Pyrenees begins Africa. Once that natural barrier is crossed, the Mediterranean racial type in all its purity confronts us. The human phenomena is entirely parallel with the sudden transition to the flora and fauna of the south. The Iberian population thus isolated from the rest of Europe, are allied in all important anthropological respects with the peoples inhabiting Africa north of the Sahara, from the Red Sea to the Atlantic." [6]
Ripley's tripartite system of race put him at odds both with others on the topic of human difference, including those who insisted that there was only one European race, and those who insisted that there were at least ten European races (such as Joseph Deniker, who Ripley saw as his chief rival). The conflict between Ripley and Deniker was criticized by Jan Czekanowski, who states, that "the great discrepancies between their claims decrease the authority of anthropology", and what is more, he points out, that both Deniker and Ripley had one common feature, as they both omitted the existence of Armenoid race, which Czekanowski claimed to be one of the four main races of Europe, met especially among the Eastern and Southern Europeans.[7] Writing at a time when such racialist theories were widely accepted among academics, Ripley was the first American recipient of the Huxley Medal of the Royal Anthropological Institute in 1908 for his contributions to anthropology.
The Races of Europe, overall, became an influential book of the era in the then-accepted field of racial taxonomy.[8] Ripley's tripartite system of racial classification was especially championed by the racist propagandist Madison Grant, who changed Ripley's "Teutonic" type into Grant's own Nordic type (taking the name, but little else, from Deniker), which he postulated as a master race.[9] It
quote:Originally posted by BlessedbyHorus: Found this gem on another site. Special thanks goes to pgbk87 from that site.
Extensive Admixture and Selective Pressure Across the Sahel Belt
quote:Genome-wide studies of African populations have the potential to reveal powerful insights into the evolution of our species, as these diverse populations have been exposed to intense selective pressures imposed by infectious diseases, diet, and environmental factors. Within Africa, the Sahel Belt extensively overlaps the geographical center of several endemic infections such as malaria, trypanosomiasis, meningitis, and hemorrhagic fevers. We screened 2.5 million single nucleotide polymorphisms in 161 individuals from 13 Sahelian populations, which together with published data cover Western, Central, and Eastern Sahel, and include both nomadic and sedentary groups. We confirmed the role of this Belt as a main corridor for human migrations across the continent. Strong admixture was observed in both Central and Eastern Sahelian populations, with North Africans and Near Eastern/Arabians, respectively, *but it was inexistent in Western Sahelian populations.* Genome-wide local ancestry inference in admixed Sahelian populations revealed several candidate regions that were significantly enriched for non-autochthonous haplotypes, and many showed to be under positive selection. The DARC gene region in Arabs and Nubians was enriched for African ancestry, whereas the RAB3GAP1/LCT/MCM6 region in Oromo, the TAS2R gene family in Fulani, and the ALMS1/NAT8 in Turkana and Samburu were enriched for non-African ancestry. Signals of positive selection varied in terms of geographic amplitude. Some genomic regions were selected across the Belt, the most striking example being the malaria-related DARC gene. Others were Western-specific (oxytocin, calcium, and heart pathways), Eastern-specific (lipid pathways), or even population-restricted (TAS2R genes in Fulani, which may reflect sexual selection).
Well, I hope these findings finally put to rest the claim that Western Sahelian folks like the Fulani are "Caucasoid-admixed" but knowing how stubborn Euronuts are, I doubt it. Posts: 26293 | From: Atlanta, Georgia, USA | Registered: Feb 2005
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