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http://www.bombasticelement.org/2011...me-out-of.htmlWith new findings giving more credence to multiregional theory of human evolution--i.e. a gradualism theory that says evolution takes place over wide areas under natural selection and whenever there is a new feature that's an advantage it spreads among the species, an alternative to the homo erectus coming out of Africa with evolutionary advantages that helped it replace other species--above, science blogger Razib Khan talks to an early skeptic of the humans came "out of Africa" hypothesis, University of Michigan paleoanthropologist Milford Wolpoff. Below is a clip from Nova's "Last Human Standing" documentary, based on the "Out of Africa" theory and provides some more backstory and illustration of the homo erectus migration out of Africa to other parts of the world:
http://www.dailymail.co.uk/sciencete...y-thought.htmlModern man's ancestor Homo erectus became extinct '108,000 years earlier than previously thought'
http://www.bbc.co.uk/news/science-environment-14947363Skull points to a more complex human evolution in Africa
http://news.yahoo.com/closest-human-...141606435.htmlClosest Human Ancestor May Rewrite Steps in Our Evolution
http://www.nature.com/news/2006/0605...060515-10.htmlChimpanzee and human ancestors may have interbred
http://blogs.discovermagazine.com/gn...humans-either/Africans aren’t pure humans either
Last year when discussing the possible admixture of Neandertals with the ancestors of modern non-Africans I joked that Sub-Saharan Africans were “pure humans.” This was tongue-in-cheek in part because the results from the Neandertal genome shifted my assessment of the probability of archaic admixture within Africa as well. In other words, there may never have been a pure “human” type which expanded and assimilated archaic ancestry on the margins of its range. Species Platonism may be very misleading for our particular lineage. Rather, what it means to be human has always been in flux, a compromise between extremely different ancestral components.
For years some groups of researchers have been arguing that there is population structure within Africa itself which hints at admixture events before (or after?) the “Out of Africa” event. Genome blogger Dienekes Pontikos has been discussing this possibility for several years as well. With the possibility of archaic admixture outside of Africa it was inevitable that people would revisit their earlier exploration of ancient African admixture and the modern patterns of variation which that might explain. Finally one of the groups working on this has come out with something in PNAS, Genetic Evidence for Archaic Admixture in Africa. Unfortunately it’s not on the website, and I’m not privy to the embargoed copy, so I can’t say much. ScienceDaily and Nature have lengthy write-ups. The details are pretty straightforward. The authors infer using computational methods that there is a 1-2% admixture in Africans of a population which diverged from the mainline of the human ancestral tree ~700,000 years ago. The hybridization occurred on the order of ~40,000 years before the present. The proportions are highest in Central Africans. I assume that this means Pygmies. And I would further bet that the admixture is highest in the Eastern Pygmy populations, such as the Mbuti. The lead author also cautions that this may not be the last word on admixture. No doubt. There are other groups breathing down his neck.
If this is true then a assimilation model of the expansion of H. sapiens sapiens looks more and more plausible. The time period of admixture is pretty much what other scholars are estimating for Neandertals, and presumably Denisovans. I’m not smart enough to figure out how this could be a statistical artifact, but perhaps that explains the congruence? Otherwise, if this is true then you had several repeated events of expansion of one particular lineage (what I term “Neo-Africans”) which demographically swamped the indigenous populations, but still retained a faint, but discernible stamp of their distinctive genetic content. But this may not be exceptional. It may have happened before the emergence of Neo-Africans, and I believe it happened after them (e.g., the rise of agriculturalists). It’s possibly one instance of a rather banal dynamic in the evolution of Homo.
http://evoandproud.blogspot.co.nz/20...-africans.htmlExpansion of modern humans out of Africa and within Africa. Mellars (2006).
When we discuss the origins of modern humans, the term ‘Out of Africa’ is a bit misleading. Our common ancestors came not from Africa as a whole but from a relatively small area somewhere in East Africa. Beginning around 80,000 years ago, this area was the scene of several population expansions that culminated in a ‘big bang’ c. 60,000 BP (Watson et al., 1997). This was a sustained expansion that pushed out of Africa and into Europe, Asia, Oceania, and the Americas.
These modern humans spread at the expense of more archaic ‘hominins’: Neanderthals in Europe and West Asia, and other poorly known groups elsewhere. But the latter were not totally replaced, as seen in the 1 to 4% Neanderthal admixture of present-day Europeans, East Asians, and Papuans. This has led some people to quip that only Africans are pure Homo sapiens:
Better yet, and a blow to Caucasian and Asian racists, the comparison of the human and Neanderthal genome makes it clear that it is only Africans who are 100 percent Homo sapiens, while in European (including American and Australian settlers) and Asian populations one can find up to 4 percent DNA stemming from the archaic and often maligned Neanderthal species - a hominid that went extinct more than 20,000 years ago. (Camphausen, 2010)
Well, no. Sub-Saharan Africans actually have more archaic admixture. The difference is that it came not from Neanderthals but from archaic groups within Africa. About 13% of the sub-Saharan gene pool comes from an earlier expansion of pre-modern hominins that occurred c. 111,000 years ago and seems to correspond to the entry of Skhul-Qafzeh hominins into the Middle East (Watson et al., 1997). This higher level of admixture may have come about because archaic Africans were behaviorally and physically closer to modern humans than the Neanderthals were.
Nonetheless, these ‘Paleoafricans’ were clearly archaic. They lacked something that modern humans had. What was this disadvantage that ultimately removed them from the struggle for existence? The answer is much debated, but most authors posit a limited capacity for symbolic thinking and social organization:
[…] the African exodus was predated by a cultural revolution involving new stone blade technologies, skin working tools, ornaments and imported red ochre […] More advanced symbolic systems in language and religious beliefs could have provided a competitive advantage to a group by promoting coordination and cohesion. (Atkinson et al., 2009)
Thus, when we discuss human origins, the real split was not between Africans and non-Africans but rather between two groups of Africans: archaics and moderns. Dienekes (2005) uses the terms ‘Paleoafricans’ and ‘Afrasians’:
It is common to distinguish between Africans and non-Africans, with the former being much more genetically diverse than the latter. But, the real "gap" in human origins seems to be between the really old Africans ("Paleoafricans") and the rest ("Afrasians").
The Paleoafrican element is entirely confined to Africa, while the Afrasian one is found in both Africa and Eurasia. Indeed, modern humans can be entirely split into two groups: (i) a group of "pure" Afrasians which includes all non-Africans, and (ii) a group of Afrasian-Paleoafricans which includes all non-Caucasoid Africans. Human groups of entirely Paleoafrican origin, unhybridized with the younger Afrasians are no longer in existence.
All of this leads to an intriguing conclusion. Since present-day sub-Saharan Africans were used as a benchmark to estimate Neanderthal admixture in present-day Eurasians, and since Paleoafrican gene sequences should be less ‘derived’ and more similar to Neanderthal gene sequences, Neanderthal admixture in present-day Eurasians is probably a bit higher than the estimated 1 to 4%.
References
Atkinson, Q.D., R.D. Gray, and A.J. Drummond. (2009). Bayesian coalescent inference of major human mitochondrial DNA haplogroup expansions in Africa, Proceedings of the Royal Society B, 276, 367–373
Camphausen, R.C. (2010). Evidence for interbreeding with Neanderthals, only Africans pure, Digital Journal, May 10, 2010,
http://www.digitaljournal.com/article/291798
Dienekes. (2005). The mitochondrial time depth of humanity, Dienekes’ Anthropology Blog, May 14, 2005.
http://dienekes.blogspot.com/2005/05...-humanity.html
Mellars, P. (2006). Why did modern human populations disperse from Africa ca. 60,000 years ago? A new model, Proceedings of the National Academy of Sciences (USA), 103, 9381-9386.
http://www.pnas.org/content/103/25/9381.abstract
Watson, E., P. Forster, M. Richards, and H-J. Bandelt. (1997). Mitochondrial footprints of human expansions in Africa, American Journal of Human Genetics, 61, 691-704.
http://evoandproud.blogspot.co.nz/20...l-complex.htmlSub-Saharan Africans have an unusual complex of dental features:
[…] compared to other world populations, Africans south of the Sahara Desert are distinct dentally — especially in their expression of nine high- and two low-frequency morphological features. This suite of traits was termed the “Sub-Saharan African Dental Complex” (SSADC); it includes the world’s highest occurrences of Bushman canine, two-rooted UP1, UM1 Carabelli’s trait, three-rooted UM2, LM2 Y-groove, LM1 cusp 7, LP1 Tom’s root, two-rooted LM2, and UM3 presence, and among the lowest occurrences of UI1 double shoveling and UM1 enamel extension. (Irish, 2011)
The two low-frequency traits appear to be “derived.” They seem to have developed in sub-Saharan Africa after modern humans began to spread to other continents. The other traits, however, are ancestral:
[…] the same nine high-frequency traits are also ubiquitous in the dentitions of extinct hominids and many extinct and extant non-human primates
[…] The presence and, indeed, prevalence (see next section), of high-frequency Sub-Saharan dental traits in fossil and recent hominoids—some of which are probably direct ancestors of modern humans, suggests they have been around for a long time. (Irish, 1998, pp. 87-88)
In addition to these traits, Irish (1998) mentions a low-frequency trait that seems likewise ancestral and specific to sub-Saharan Africans:
A final ancestral feature found with some regularity in Sub-Saharan Africans, relative to other modern groups, is polydontia. Numerous cases of extra incisors, third premolars, and fourth molars have been noted […] In one study (Watters, 1962) the incidence reached 2.5-3% in several hundred west Africans; many of the extra teeth were fully formed and erupted. “Typical” mammals exhibit three incisors and four premolars (Jordan et al., 1992). Polydontia is also found in living non-human primates […] (Irish, 1998, p. 88)
Why are these ancestral traits much more common in sub-Saharan Africans than in other humans? There are several possible reasons. One is that non-Africans began as a small founder group and thus lost much of the dental variability that still characterizes Africans. Another reason might be that natural selection favored new forms of dentition outside Africa, perhaps as a response to new food sources or new ways of preparing food.
But there’s a third possible reason: archaic admixture. Just as modern humans mixed to some extent with Neanderthals in Europe and Denisovans in Asia, perhaps there was also mixture with archaic hominins in Africa, and perhaps this admixture introduced archaic dental features into present-day Africans.
But how could present-day Africans have archaic admixture? If modern humans originated in Africa, wouldn’t they have encountered archaic humans only in Europe and Asia?
Well, at first, modern humans did not occupy all of Africa. They were initially a small population somewhere in East Africa. Then, around 80,000 years ago, this population began to expand northward and eventually into Eurasia (Watson et al., 1997). Meanwhile, the same expansion was taking modern humans westward and southward into other parts of Africa.
Just whom exactly did these modern humans encounter during their expansion within Africa? Initially, they probably met hominins who looked the same but still lacked some of the mental rewiring that gave modern humans a competitive edge. These “almost-moderns” account for about 13% of the current sub-Saharan gene pool and may have been related to the Skhul-Qafzeh hominins who occupied the Middle East 120,000 to 80,000 years ago (Watson et al., 1997).
As modern humans spread further west and south within Africa, they encountered much more archaic hominins, and perhaps even lingering Homo erectus groups. About 2% of the modern African genome comes from an archaic population that split from ancestral modern humans some 700,000 years ago. This admixture is dated to about 35,000 years ago and may have occurred in Central Africa, since the level of admixture is highest in pygmy groups from that region (Hammer et al., 2011).
A more tangible sign of admixture is visible in a skull retrieved from the Iwo Eleru rock shelter, in southwestern Nigeria, and dated to approximately 16,300 BP:
Our analysis indicates that Iwo Eleru possesses neurocranial morphology intermediate in shape between archaic hominins (Neanderthals and Homo erectus) and modern humans. This morphology is outside the range of modern human variability in the PCA and CVA analyses, and is most similar to that shown by LPA individuals from Africa and the early anatomically modern specimens from Skhul and Qafzeh.
[… ] the transition to anatomical modernity in Africa was more complicated than previously thought, with late survival of “archaic” features and possibly deep population substructure in Africa during this time. (Harvati et al., 2011)
Then there is the Broken Hill skull, found near Kabwe, Zambia and dated to 110,000 BP (Bada et al., 1974). It looks for all the world like a Homo erectus. Textbooks generally try to raise it to Homo sapiens status or argue for an earlier dating. Recently, a late dating has been confirmed by Stringer (2011).
Interestingly, when Irish (2011) compared dentitions from west, central, east, and south Africa, ranging in age from the late Pleistocene to the mid-1950s, the early Holocene Kenyans and Tanzanians were the sample that had the fewest ancestral traits of the Sub-Saharan African Dental Complex (SSADC). In other words, the SSADC seems to have been least present in the “homeland” of modern humans (East Africa) and more present farther west and south.
Given the high level of archaic admixture in sub-Saharan Africans, we may have to revise downwards the estimate of 1 to 4% Neanderthal admixture in Eurasians. Yes, Eurasians are closer than sub-Saharan Africans to the Neanderthal genome. But is this discrepancy solely due to Neanderthal admixture in Eurasians? Could it also be due to Sub-Saharan Africans becoming further removed from the Neanderthal genome through admixture with other archaic groups?
The past may be a stranger country than previously thought. When farming villages began to form in the Middle East, there may still have been archaic hominins roaming over parts of western and southern Africa.
References
Bada, J.L., R.A. Schroeder, R. Protsch, & R. Berger. (1974). Concordance of Collagen-Based Radiocarbon and Aspartic-Acid Racemization Ages, Proceedings of the National Academy of Sciences (USA), 71, 914-917.
Hammer, M.F., A.E. Woerner, F.L. Mendez, J.C. Watkins, and J.D. Wall. (2011). Genetic evidence for archaic admixture in Africa, Proceedings of the National Academy of Science (USA), 108, 15123-15128, www.pnas.org/cgi/doi/10.1073/pnas.1109300108
Irish, J.D. (2011). Afridonty: the “Sub-Saharan African Dental Complex” revisited, American Journal of Physical Anthropology, 144(supp. 52), 174
Irish, J.D. (1998). Ancestral dental traits in recent Sub-Saharan Africans and the origins of modern humans, Journal of Human Evolution, 34, 81-98.
Harvati, K., C. Stringer, R. Grün, M. Aubert, P. Allsworth-Jones, C.A. Folorunso. (2011). The Later Stone Age Calvaria from Iwo Eleru, Nigeria: Morphology and Chronology. PLoS ONE 6(9): e24024. doi:10.1371/journal.pone.0024024
http://www.plosone.org/article/info%...l.pone.0024024
Stringer, C. (2011). The chronological and evolutionary position of the Broken Hill cranium. American Journal of Physical Anthropology, 144(supp. 52), 287
Watson, E., P. Forster, M. Richards, and H-J. Bandelt. (1997). Mitochondrial footprints of human expansions in Africa, American Journal of Human Genetics, 61, 691-704.
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The Bantu are Capoid.
There were Melanesians there tooLike a Filipino mixed with a Mozambican
Filipino:Modern Filipino= Melanesian + Micronesian +European (Spanish heritage in some or dirty old European men)
http://en.wikipedia.org/wiki/MicronesiaThe people today form many ethnicities, but are all descended from and belong to the Micronesian culture. The Micronesian culture was one of the last native cultures of the region to develop. It developed from a mixture of Melanesians, Polynesians, and Filipinos. Because of this mixture of descent, many of the ethnicities of Micronesia feel closer to some groups in Melanesia, Polynesia or the Philippines. A good example of this are the Yapese who are related to Austronesian tribes in the Northern Philippines
http://en.wikipedia.org/wiki/PolynesiaAt about 2000 BC speakers of Austronesian languages began spreading from Taiwan into Island Southeast Asia.[8][9][10] Their speech of the time was not clearly related to Chinese speech of the time and Chinese speakers were all further north on the mainland at the turn of the second and third millennia BC. Taiwan was only later Sinicized via large-scale immigration accompanied by much assimilation of the Austronesian speaking indigenous people during the 17th century AD.
There are three theories regarding the spread of humans across the Pacific to Polynesia. These are outlined well by Kayser et al. (2000)[11] and are as follows:
Express Train model: A recent (c. 2,000 BC) expansion out of Taiwan, via the Philippines and eastern Indonesia and from the northwest ("Bird's Head") of New Guinea, on to Island Melanesia by roughly 1,400 BC years ago, reaching western Polynesian islands right about 900 BC. This theory is supported by the majority of current human genetic data, linguistic data, and archaeological data.[citation needed]
Entangled Bank model: Emphasizes the long history of Austronesian speakers' cultural and genetic interactions with indigenous Island Southeast Asians and Melanesians along the way to becoming the first Polynesians.[citation needed]
Slow Boat model: Similar to the express-train model but with a longer hiatus in Melanesia along with admixture, both genetically, culturally and linguistically with the local population. This is supported by the Y-chromosome data of Kayser et al. (2000), which shows that all three haplotypes of Polynesian Y chromosomes can be traced back to Melanesia
The Negritos and Melanesians were in the Philippines too.
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Don't be ridiculous. There's one species, races are sub-species in effect.
I'd say human races are an example of various sub-species. They may be different species capable of interbreeding if the multi-regional hypothesis can be proved right. If they diverged from a common ancestor though, then they are sub-species.Subspecies (commonly abbreviated subsp. or ssp.) in biological classification is either a taxonomic rank subordinate to species, or a taxonomic unit in that rank (plural: subspecies). A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one. (However, all but one subspecies may be extinct, as in Homo sapiens sapiens.)
Organisms that belong to different subspecies of the same species are capable of interbreeding and producing fertile offspring, but they often do not interbreed in nature due to geographic isolation or other factors. The differences between subspecies are usually less distinct than the differences between species, but more distinct than the differences between breeds or races (races can be assigned to different subspecies if taxonomically different). The characteristics attributed to subspecies generally have evolved as a result of geographical distribution or isolation.
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In short? That I agree with those charts on genetic distance in which the boundary seems to consistently determine five human macroclusters or 'races':
- Subsaharans
- Sahulians*
- Austronesians
- Asians&Americans
- Caucasians
*I prefer this term to Australasians or Australo-Papuans.
< La Catalogne peut se passer de l'univers entier, et ses voisins ne peuvent se passer d'elle. > Voltaire
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Only 4 IMO, Caucasoid, Negroid, Mongoloid and Australoid
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I would say that capoids are Negroid-Mongoloid mixed, as well as uraloid are Europioid-Mongoloid mixed. I don't think that they will be separate races.I think it is necessary to allocate 4 biggest races: the Negroid, Australoid, Mongoloid, Europoid
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I have already described why the human species is polytypic and not monotypic in countless posts. I won't do it again. For those who deny the existance of race, please take in regard that the question applies to biological subsets of the human population, for that matter it isn't a social construct and certainly in accordance with our understanding of evolution and genetics. I will argue that humanity is far less polytypic the more specialized you get. So the sub-races are certainly far more mixed than the the standard races. This only makes sense logically, to those who understand how populations work. I don't believe Modern Europe is polytipic due to extensive mixtures, but it was in its past, for example.
As for the number of races. That is a matter only revealed by analyzing the sum of the distinctions through a taxonomical method. This could be due to analogous traits or more concrete molecular biological data, such as genetic deviations. We can't even consistently classify the number of kingdoms of life, how are we to categorize humanity, a far more specialized group? In the end it is a fluid procedure with constant improvement as we learn more and more.
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Caucasian
-Germanic
-Slavic
-Latin
-Semitic
-Kushitic
-Iranian
-Indian
-Kavkaz
Congoid
-West Africans
Capoid
-East Africans
Mongoloid
-East Asians
-Amerindians
-Turanians
Australoid
-Aborigenes
-Dravidians
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