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Error Found in Study of First Ancient African Genome Finding that much of Africa has Eurasian ancestry was mistaken
quote:An error has forced researchers to go back on their claim that humans across the whole of Africa carry DNA inherited from Eurasian immigrants. This week the authors issued a note explaining the mistake in their October 2015 Science paper on the genome of a 4,500-year-old man from Ethiopia—the first complete ancient human genome from Africa. The man was named after Mota Cave, where his remains were found (For more about the initial findings, please read the following article: “First Ancient African Genome Reveals Vast Eurasian Migration”). Although the first humans left Africa some 100,000 years ago, a study published in 2013 found that some came back again around 3,000 years ago; this reverse migration has left its trace in African genomes. In the Science paper, researchers confirmed this finding. The paper also suggested that populations across the continent still harbour significant ancestry from the Middle Eastern farmers who were behind the back-migration. Populations in East Africa, including Ethiopian highlanders who live near Mota Cave, carried the highest levels of Eurasian ancestry. But the team also found vestiges of the ‘backflow’ migration in West Africans and in a pygmy group in Central Africa, the Mbuti. Andrea Manica, a population geneticist at the University of Cambridge, UK, who co-led the study, says the team made a mistake in its conclusion that the backflow reached western and central Africa. “The movement 3,000 years ago, or thereabouts, was limited to eastern Africa,” he says. Incompatible software Manica says that the error occurred when his team compared genetic variants in the ancient Ethiopian man with those in the reference human genome. Incompatibility between the two software packages used caused some variants that the Ethiopian man shared with Europeans (whose DNA forms a large chunk of the human reference sequence) to be removed from the analysis. This made Mota man seem less closely related to modern European populations than he actually was—and in turn made contemporary African populations appear more closely related to Europeans. The researchers did have a script that they could have run to harmonize the two software packages, says Manica, but someone forgot to run it. Pontus Skoglund, a population geneticist at Harvard Medical School in Boston, Massachusetts, says that he was surprised by the claim that as much as 6–7% of the ancestry of West and Central African groups came from the Eurasian migrants. But after obtaining the Mota man’s genome from Manica’s team, he and his colleague David Reich carried out their own comparison and found no evidence for that conclusion. They informed Manica’s team, who then discovered the processing error. “Almost all of us agree there was some back-to-Africa gene flow, and it was a pretty big migration into East Africa,” says Skoglund. “But it did not reach West and Central Africa, at least not in a detectable way.” The error also undermines the paper’s original conclusion that many Africans carry Neanderthal DNA (inherited from Eurasians whose ancestors had interbred with the group). Skoglund praised the paper—“the genome itself is just fantastic,” he says—and the researchers’ willingness to share their data and issue a speedy note about the error: they posted it online on January 25. When asked to confirm whether and when it would publish the researchers' update, a representative for Science said the journal couldn't yet comment. Manica is not yet sure if Science will change the title of the paper, ‘Ancient Ethiopian genome reveals extensive Eurasian admixture throughout the African continent’. But if the team had caught the error earlier, he says, “I’m sure we would have phrased things differently”. This article is reproduced with permission and was first published on January 29, 2016.
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East Africans are the bridge between out of Africa and in(-ner) Africa migration. There was no mass back migration from "eurasia", perhaps some snippets here and there at max. Bidirectionally the same people lived on both sides of the Red Sea, a population('s) which originated at East Africa in the first place.
quote: Breton et al. analyze lactase persistence variants and genome-wide SNPs among southern African groups and show that Khoe pastoralists have partial East African ancestry. This finding suggests that an East African group migrated south, brought pastoralism to southern Africa, and admixed with local hunter-gatherers to form the ancestors of Khoe.
--Gwenna Breton et al.
Lactase Persistence Alleles Reveal Partial East African Ancestry of Southern African Khoe Pastoralists
Received: November 26, 2013; Received in revised form: December 20, 2013; Accepted: February 15, 2014; Published Online: April 03, 2014 Published: April 3, 2014 DOI: http://dx.doi.org/10.1016/j.cub.2014.02.041
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Europeans had to reject this article because if you flip the script it indicates an African origin of Eurasians because Mota man was supposed to be unmixed.
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MOST studies show that Africans carry “Eurasian” ancestry. Even “Neanderthal” ancestry. It decreases North to South…….or increases South to North. Even the Hunter Gatherers Hadza and Bantus carry “Eurasian” ancestry. Gone are the days when ONE person held all the cards…or held all the information. Lol! Too late. The cat is out the bag. Lol!
Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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---- Genome-wide analyses of African populations ARE REFINING PREVIOUS MODELS of the continent's genetic history. One such emerging insight is the identi_cation of clear, but complex, evidence for the movement of Eurasian ancestry back into the continent as a result of admixture over a variety of timescales [Pagani et al., 2012; Pickrell et al., 2014; Gurdasani et al., 2014; Hodgson et al., 2014a; Llorente et al., 2015]. Admixture occurs when genetically differentiated ancestral groups come together and mix, a process which is increasingly regarded as a common feature of human populations across the globe [Patterson et al., 2012; Hellenthal et al., 2014; Busby et al., 2015]. In a broad sample of 18 ethnic groups from eight countries, the African Genome Variation Project (AGVP) [Gurdasani et al., 2014] recreated previously published results to identify recent Eurasian admixture within the last 1.5 thousand years (ky) in the Fulani of West Africa [Tishkoff et al., 2009; Henn et al., 2012] and several East African groups from Kenya, older Eurasian ancestry (2-5 ky) in Ethiopian groups, consistent with previous studies of similar populations [Pagani et al., 2012; Pickrell et al., 2014], and a novel signal of ancient (>7.5 ky) Eurasian admixture in the Yoruba of Central West Africa [Gurdasani et al., 2014]. Comparisons of contemporary sub-Saharan African populations with the fist ancient genome from within Africa, a 4.5 ky Ethiopian individual [Llorente et al., 2015], provide additional support for limited migration of Eurasian ancestry back into East Africa within the last 3,000 years.
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-------------------- Without data you are just another person with an opinion - Deming Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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"Eurasian" ancestry is found throughout Africa but it is NOT Eurasian !!!!!!!
-------------------- Without data you are just another person with an opinion - Deming Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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Quote from Busy : At finer scales, our analysis reveals smaller groups, and often differentiates closely related populations consistent with self-reported ancestry [Tishkoff et al., 2009; Bryc et al., 2010; Hodgson et al., 2014a]. We describe these patterns by measuring gene flow between populations and relate them to POTENTIAL historical movements of people into and within sub-Saharan Africa. Understanding the extent to which individuals share haplotypes (which we call coancestry), rather than independent markers, can provide a rich description of ancestral relationships and population history [Lawson et al.,
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Translation: - We find the evidence and make a fantastic story to fit the evidence. The most popular is fantasy is BACK-MIGRATION or slaves. Lol!
-------------------- Without data you are just another person with an opinion - Deming Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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So East African Niger Congo are ancestral to AfroAsiatic who in turn ancestral to Europeans?
Here are some interesting parts from the new Busby et al Study – Quote ------ GLOBETROTTER is designed to identify the most recent admixture event(s) [Hellenthal et al., 2014], this observation does not rule out genefow from Eurasia back into these groups, but does suggest that subsequent movements between African groups were important in generating the contemporary ancestry of Central West and Southern African Niger-Congo speaking groups. With some exceptions that we describe below, we also do not observe Eurasian ancestry in all East African Niger-Congo speakers, instead finding more evidence for coancestry with Afroasiatic speaking groups. As we show later, Afroasiatic populations have a significant amount of genetic ancestry from outside of Africa, so the observation of this ancestry in several African groups identifies a route by which Eurasian ancestry may have indirectly entered the continent [Pickrell et al., 2014]. In fact, characterising admixture sources as mixtures allows us to infer whether Eurasian haplotypes are likely to have come directly into sub-Saharan Africa { in which case the admixture source will contain only Eurasian surrogates { or whether Eurasian haplotypes were brought indirectly together with sub- Saharan groups. In West African Niger-Congo speakers from The Gambia and Mali, we infer admixture involving minor admixture sources which contain mostly Eurasian (dark yellow) and CentralWest African (sky blue) ancestry, which most closely match the contemporary copying vectors of northern European populations (CEU and GBR)!!!!!!!!!! or the Fulani (FULAI, highlighted in gold in Figure 4A). The Fulani, a nomadic pastoralist group found across West Africa, were sampled in The Gambia, at the very western edge of their current range, and have previously reported genetic affinities with Niger-Congo speaking, Sudanic, Saharan, and Eurasian populations [Tishko_ et al., 2009; Henn et al., 2012], consistent with the results of our mixture model analysis (Figure 4A). Admixture in the Fulani differs from other populations from this region, with sources containing greater amounts of Eurasian and Afroasiatic ancestry, but appears to have occurred during roughly the same period (c. 0CE; Figure 5).
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-------------------- Without data you are just another person with an opinion - Deming Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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Quote: - Busby et al “In West African Niger-Congo speakers from The Gambia and Mali, we infer admixture involving minor admixture sources which contain mostly Eurasian (dark yellow) and CentralWest African (sky blue) ancestry, “which most closely match the CONTEMPORARY copying vectors of northern European populations (CEU and GBR
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Can anyone say European Hunter Gatherer. Lol! A connection between Central Africans and Scandinavians. Where and when did I hear that script before? Lol! This is so easy. It is a continuum. These authors are insistent on maintaining there are “races”. Remember I said in that Neolithic thread on LBK/La Brana/Anatolia/Grece is Africa that they will find La Brana material in Central Africa. Well here you go. If I am a betting man my money is on the CEU material is La Brana genetic material. The migration pattern is overwhelmingly obvious.
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-------------------- Without data you are just another person with an opinion - Deming Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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Wow thanks for posting this. So the large scale Eurasian migration back into Africa occurred around 3,000 years ago? Wouldn't that be around the time of the Late Period in Egypt?
Also I'm a little confused, so are they now saying Mota himself was mixed?
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Meet on the Level, act upon the Plumb, part on the Square. Posts: 574 | From: Guinee | Registered: Jul 2014
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I find it amusing and ironic at the same time.
quote: The Garamantes flourished in southwestern Libya, in the core of the Sahara Desert ~3,000 years ago and largely controlled trans-Saharan trade. Their biological affinities to other North African populations, including the Egyptian, Algerian, Tunisian and Sudanese, roughly contemporary to them, are examined by means of cranial nonmetric traits using the Mean Measure of Divergence and Mahalanobis D(2) distance. The aim is to shed light on the extent to which the Sahara Desert inhibited extensive population movements and gene flow. Our results show that the Garamantes possess distant affinities to their neighbors. This relationship may be due to the Central Sahara forming a barrier among groups, despite the archaeological evidence for extended networks of contact. The role of the Sahara as a barrier is further corroborated by the significant correlation between the Mahalanobis D(2) distance and geographic distance between the Garamantes and the other populations under study. In contrast, no clear pattern was observed when all North African populations were examined, indicating that there was no uniform gene flow in the region.
--Nikita E1, Mattingly D, Lahr MM.
Am J Phys Anthropol. 2012 Feb;147(2):280-92. doi: 10.1002/ajpa.21645. Epub 2011 Dec 20. Sahara: Barrier or corridor? Nonmetric cranial traits and biological affinities of North African late Holocene populations.
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