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Fences and windows (talk | contribs) Deleting roll-call of researchers as based on original research - some of the interpretations were wrong. General clean-up. Edit conflict, will resolve. |
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[[Image:Multiregionaltheory.gif|thumb|300px|right|A graph detailing the origin of modern humans using the Multiregional theory of [[human evolution]]. The horizontal lines represent 'multiregional evolution' gene flow between regional lineages.]] |
[[Image:Multiregionaltheory.gif|thumb|300px|right|A graph detailing the origin of modern humans using the Multiregional theory of [[human evolution]]. The horizontal lines represent 'multiregional evolution' gene flow between regional lineages.]] |
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In [[anthropology|paleoanthropology]], the '''multiregional hypothesis''' is a theory of the |
In [[anthropology|paleoanthropology]], the '''multiregional hypothesis''' is a theory of the origin of [[anatomically modern humans]], ''Homo sapiens sapiens''. The multiregional hypothesis holds that the [[Human evolution|evolution of humanity]] throughout the [[Pleistocene]] (1.8 million to 10,000 [[ybp|years before present]]) has been within a single, continuous [[human species]], evolving worldwide from ''[[Homo erectus]]'' to modern ''Homo sapiens''.<ref>{{cite journal|last=Wolpoff|first=MH|coauthors=Hawks J, Caspari R|date=2000|title=Multiregional, not multiple origins|journal=Am J Phys Anthropol|volume=112|issue=1|pages=129-36|url=http://www3.interscience.wiley.com/journal/71008905/abstract}}</ref> |
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A competing theory of the [[recent African origin of modern humans]] (also known as "Out of Africa") has emerged as the near consensus view since the 1990s,<ref>Hua Liu, et al. [http://dx.doi.org/10.1086/505436 A Geographically Explicit Genetic Model of Worldwide Human-Settlement History]. ''American Journal of Human Genetics'', volume 79 (2006), pages 230–237, quote: ''Currently available genetic and archaeological evidence is generally interpreted as supportive of a recent single origin of modern humans in East Africa. However, this is where '''the near consensus''' on human settlement history ends, and considerable uncertainty clouds any more detailed aspect of human colonization history.''</ref> proposing that modern humans arose in Africa around 100 |
A competing theory of the [[recent African origin of modern humans]] (also known as "Out of Africa") has emerged as the near consensus view since the 1990s,<ref>Hua Liu, et al. [http://dx.doi.org/10.1086/505436 A Geographically Explicit Genetic Model of Worldwide Human-Settlement History]. ''American Journal of Human Genetics'', volume 79 (2006), pages 230–237, quote: ''Currently available genetic and archaeological evidence is generally interpreted as supportive of a recent single origin of modern humans in East Africa. However, this is where '''the near consensus''' on human settlement history ends, and considerable uncertainty clouds any more detailed aspect of human colonization history.''</ref><ref>{{cite journal|last=Weaver|first=Timothy D|coauthors=Charles C. Roseman|date=2008|title=New developments in the genetic evidence for modern human origins|journal=Evolutionary Anthropology: Issues, News, and Reviews|publisher=Wiley-Liss|volume=17|issue=1|pages=69-80|url=http://www3.interscience.wiley.com/journal/117921411/abstract}}</ref> proposing that modern humans arose in Africa around 100-200,000 years ago, moving out of Africa around 50-60,000 years ago to replace existing human species such as ''Homo erectus'' and the [[Neanderthals]].<ref>{{cite journal|last=Fagundes|first=NJ|coauthors=Ray N, Beaumont M, Neuenschwander S, Salzano FM, Bonatto SL, Excoffier L.|date=2007|title=Statistical evaluation of alternative models of human evolution|journal=Proc Natl Acad Sci U S A|volume=104|issue=45|pages=17614-9|url=http://www.pnas.org/content/104/45/17614.long}}</ref> |
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Advocates of the multiregional hypothesis point to some recent [[Multiregional origin of modern humans#Genetic evidence|genetic data|^]]<ref>{{cite journal|last=Cox|first=MP|coauthors=Mendez FL, Karafet TM, Pilkington MM, Kingan SB, Destro-Bisol G, Strassmann BI, Hammer MF|date=2008|title=Testing for archaic hominin admixture on the X chromosome: model likelihoods for the modern human RRM2P4 region from summaries of genealogical topology under the structured coalescent|journal=Genetics|volume=178|issue=1|pages=427-37|url=http://www.genetics.org/cgi/content/full/178/1/427}}</ref> as support for their hypothesis, and some interbreeding (or "[[Admixture (genetics)|admixture]]") between modern humans and previous human species has not been ruled out,<ref>{{cite journal|last=Relethford |first=JH|date=2008|title=Genetic evidence and the modern human origins debate|journal=Heredity|publisher=Macmillan|volume=100|issue=6|pages=555-63}}</ref> although it is increasingly unlikely for Neanderthals.<ref>{{cite journal|last=Hodgson|first=JA|coauthors=Disotell TR|date=2008|title=No evidence of a Neanderthal contribution to modern human diversity.|journal=Genome Biology|publisher=BioMed Central|volume=9|issue=2|pages=206|url=http://genomebiology.com/2008/9/2/206}}</ref><ref>{{cite journal|last=Belle|first=EM|coauthors=Benazzo A, Ghirotto S, Colonna V, Barbujani G.|date=2009|title=Comparing models on the genealogical relationships among Neandertal, Cro-Magnoid and modern Europeans by serial coalescent simulations|journal=Heredity|publisher=Macmillan|location=London|volume=102|issue=3|pages=218-25|url=http://www.nature.com/hdy/journal/v102/n3/full/hdy2008103a.html}}</ref> To differentiate between early historical, unscientific conceptions some researchers prefer to use term |
Advocates of the multiregional hypothesis point to some recent [[Multiregional origin of modern humans#Genetic evidence|genetic data|^]]<ref>{{cite journal|last=Cox|first=MP|coauthors=Mendez FL, Karafet TM, Pilkington MM, Kingan SB, Destro-Bisol G, Strassmann BI, Hammer MF|date=2008|title=Testing for archaic hominin admixture on the X chromosome: model likelihoods for the modern human RRM2P4 region from summaries of genealogical topology under the structured coalescent|journal=Genetics|volume=178|issue=1|pages=427-37|url=http://www.genetics.org/cgi/content/full/178/1/427}}</ref> as support for their hypothesis, and some interbreeding (or "[[Admixture (genetics)|admixture]]") between modern humans and previous human species has not been ruled out,<ref>{{cite journal|last=Relethford |first=JH|date=2008|title=Genetic evidence and the modern human origins debate|journal=Heredity|publisher=Macmillan|volume=100|issue=6|pages=555-63}}</ref><ref name="http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VS0-4M21SWT-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=43bc2fdddd454c715ebfe27b4ad6a48a">{{cite journal|last=Wall|first=JD|coauthors=Hammer MF|date=2006|title=Archaic admixture in the human genome|journal=Curr Opin Genet Dev|volume=16|issue=6|pages=606-10}}</ref> although it is increasingly unlikely for Neanderthals.<ref>{{cite journal|last=Hodgson|first=JA|coauthors=Disotell TR|date=2008|title=No evidence of a Neanderthal contribution to modern human diversity.|journal=Genome Biology|publisher=BioMed Central|volume=9|issue=2|pages=206|url=http://genomebiology.com/2008/9/2/206}}</ref><ref>{{cite journal|last=Belle|first=EM|coauthors=Benazzo A, Ghirotto S, Colonna V, Barbujani G.|date=2009|title=Comparing models on the genealogical relationships among Neandertal, Cro-Magnoid and modern Europeans by serial coalescent simulations|journal=Heredity|publisher=Macmillan|location=London|volume=102|issue=3|pages=218-25|url=http://www.nature.com/hdy/journal/v102/n3/full/hdy2008103a.html}}</ref> To differentiate between early historical, unscientific conceptions some researchers prefer to use term '''multiregional evolution''' instead of ''multiregional hypothesis of human evolution''. |
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== |
==History== |
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===Polygenism=== |
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Besides [[Milford H. Wolpoff]], Wu Xinzhi, and Alan G. Thorne,<!-- BROKEN M., Smith, F, |
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{{main|Polygenism}} |
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--> [[paleoanthropology|paleoanthropologists]] most closely associated with the multiregional hypothesis include James Calcagno<ref |
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An older theory is polygenic evolution, a multiple origins theory in which the different human populations or races had independent origins and evolved in isolation from each other. It was held by many scholars of the 19th century such as Haeckel and Klaatsch. [[Polygenism]] is sometimes mistaken for multiregional evolution, because they are both hypotheses of evolution within a single species. However, polygenic evolution depends on isolation of populations while multiregional evolution requires population interactions and interbreeding so that genetic changes can spread throughout the human range, especially when they are promoted by natural selection. According to the multiregional hypothesis, geographic differences between human populations are the results of [[climate change|climatic variation]], [[Geographical isolation|isolation by distance]], [[sexual selection]], and historical accidents ([[genetic drift]]). |
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>[http://www.luc.edu/depts/anthropology/jmc/calcagno.html Calcagno homepage link]</ref>, John Hawks<ref |
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>[http://www.johnhawks.net John Hawks homepage link]</ref> and [[Erik Trinkaus]]. |
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===Weidenreich-Coon=== |
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Today science is based on multidisciplinary research. In the field of multiregional evolution other published authors and researchers include (random sampling order, an incomplete list):{{2 |
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The multiregional hypothesis has its origin in the work of [[Franz Weidenreich]] in the 1930s. At that time, Weidenreich originated the "Weidenreich Theory of Human Evolution" based on his examination of [[Peking Man]]. Weidenreich was an anatomist and observed numerous anatomical characteristics that he thought Peking Man had in common with modern [[Asian people|Asians]]. The Weidenreich Theory stated that human races have evolved independently in the [[Old World]] from ''[[Homo erectus]]'' to ''[[Homo sapiens|Homo sapiens sapiens]]'', while at the same time there was gene flow between the various populations. According to the theory proposed by Weidenreich, genes that were generally adaptive (such as those for intelligence) flowed relatively rapidly from one part of the world to the other, while those that were locally adaptive, would not. A vocal proponent of the Weidenreich theory was [[Carleton S. Coon|Carleton Coon]]. |
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==Regional continuity== |
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}} |
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The term "multiregional hypothesis" was first coined in the early 1980s by [[Milford H. Wolpoff]] and a group of associates as an explanation for the apparent similarities of the remains from the ''[[Homo erectus]]'' and ''[[Homo sapiens]]'' inhabiting the same region, what they called ''regional continuity''. |
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:Rachel Caspari<ref |
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>[http://www3.interscience.wiley.com/journal/71008905/abstract?CRETRY=1&SRETRY=0 abstract]</ref |
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Wolpoff proposed an explanation based on [[cline (population genetics)|clinal variation]] that would allow for the necessary balance. He proposed that ''Homo erectus'', Neanderthals, Homo sapiens and other humans were a single species. This species arose in Africa two million years ago as ''H. erectus'' and then spread out over the world, developing adaptations to regional conditions. It was proposed that for periods of time some populations became isolated, developing in a different direction, but through continuous interbreeding, replacement, [[genetic drift]] and other vehicles of [[evolution]], adaptations that were an advantage anywhere on earth would spread, keeping the development of the species in the same overall direction, while maintaining adaptations to regional factors. Eventually, the more unusual local varieties of the species would have disappeared in favor of modern humans while retaining some regional adaptations, but also with many common features. |
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>, Daniel Garrigan, Zahra Mobasher, Tesa Severson, Jason A. Wilder, Michael F. Hammer<ref |
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>Evidence for Archaic Asian Ancestry on the Human X Chromosome; Molecular Biology and Evolution 2005 22(2):189-192; doi:10.1093/molbev/msi013, Daniel Garrigan, Zahra Mobasher, Tesa Severson, Jason A. Wilder, Michael F. Hammer [http://mbe.oxfordjournals.org/cgi/content/abstract/22/2/189]</ref |
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>, Stephen F. Schaffner<ref |
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>http://www.broad.mit.edu/~sfs/nrg_Xchrom.pdf</ref>, Sarah B. Kingan<ref |
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>Deep Haplotype Divergence and Long-Range Linkage Disequilibrium at Xp21.1 Provide Evidence That Humans Descend From a Structured Ancestral Population; Genetics, Vol. 170, 1849-1856, August 2005, Copyright © 2005 |
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doi:10.1534/genetics.105.041095 [http://www.genetics.org/cgi/content/abstract/170/4/1849]</ref |
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>, D. Curnoea<ref |
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>Number of ancestral human species: a molecular perspective ; doi:10.1078/0018-442X-00051 [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B7GW4-4DPCJ1N-10&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=<!-- |
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-->d&view=c&_version=1&_urlVersion=0&_userid=10&md5=24407957080d4da785fc3eb6da521133]</ref |
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>, Y. Satta, N. Takahata<ref |
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>The distribution of the ancestral haplotype in finite stepping-stone models with population expansion, [http://www3.interscience.wiley.com/journal/118794887/abstract]</ref |
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>, Alan R. Rogers, Stephen Wooding, Chad D. Huff, Mark A. Batzer, Lynn B. Jorde<ref |
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>Ancestral Alleles and Population Origins: Inferences Depend on Mutation Rate; Molecular Biology and Evolution 2007 24(4):990-997; doi:10.1093/molbev/msm018 [http://mbe.oxfordjournals.org/cgi/content/abstract/24/4/990] |
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</ref |
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>, Eugène Morin <ref |
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> LATE PLEISTOCENE POPULATION INTERACTION IN WESTERN EUROPE |
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AND MODERN HUMAN ORIGINS: NEW INSIGHTS BASED ON THE FAUNAL |
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REMAINS FROM SAINT-CÉSAIRE, SOUTHWESTERN FRANCE |
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quote: In this scenario, Neandertals would be no more than a peripheral modern human population shaped through natural selection and genetic drift by the local conditions (Thorne and Wolpoff 1981; Wolpoff 1999). Another conclusion emerging from this study is that adaptation, genetic drift, and natural selection are key issues to the problem. These aspects must be integrated in future attempts at solving the debate on the Middle to Upper Paleolithic transition. Likewise, these endeavors will only be viable if they incorporate findings from evolutionary |
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biology, human genetics, physical anthropology, and archaeology. This is because the solution does not lie in DNA, nor will it be found in a complex description of the Aurignacian 0 reduction sequences, or of a new “hybrid” fossil. The solution will only emerge by integrating the information from each of these approaches. Hopefully, this study has been successful in this respect. [http://www.paleoanthro.org/dissertations/Eugene%20Morin.pdf] |
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</ref |
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> |
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==Classification of hominid species== |
==Classification of hominid species== |
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Evaluation of the multiregional theory revolves around the assumption or non-assumption of [[species barrier]]s between early hominids. Because of the scarcity of [[fossil]]s and the discovery of important new finds every few years, researchers disagree about the details and sometimes even basic elements of [[human evolution|human evolutionary history]]. While they have revised this history several times over the last decades, researchers currently agree that the oldest named [[species]] of the genus ''[[Homo (genus)|Homo]]'', ''[[Homo habilis]]'', evolved in Africa around two million years ago, and that members of the genus migrated out of Africa somewhat later, at least 1.5 million years ago. The descendants of these ancient migrants, which probably included ''[[Homo erectus]]'', have become known through fossils uncovered far from Africa, such as those of "[[Peking man]]" and "[[Java man]]". ''[[Homo neanderthalensis]]'' is also considered a descendant of early migrants. |
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Evaluation of the Multiregional theory revolves around the assumption or non-assumption of [[species barrier]]s between early hominids. |
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==Fossil evidence== |
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Because of the scarcity of [[fossil]]s and the discovery of important new finds every few years, researchers disagree about the details and sometimes even basic elements of [[human evolution|human evolutionary history]]. While they have revised this history several times over the last decades, researchers currently agree that the oldest named [[species]] of the genus ''[[Homo (genus)|Homo]]'', ''[[Homo habilis]]'', evolved in Africa around two million years ago, and that members of the genus migrated out of Africa somewhat later, at least 1.5 million years ago. The descendants of these ancient migrants, which probably included ''[[Homo erectus]]'', have become known through fossils uncovered far from Africa, such as those of "[[Peking man]]" and "[[Java man]]". ''[[Homo neanderthalensis]]'' is also considered a descendant of early migrants. |
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Studies on past [[population bottleneck]]s that can be inferred from molecular data have led multiregionalists to conclude that the [[recent single-origin hypothesis]] is untenable because there are no population size bottlenecks affecting all genes that are more recent than the one at the beginning of the species, some 2 million years ago. Multiregionalists claimed that the discovery of a possible hybrid ''Homo sapiens X neanderthalensis'' fossil child at the [[Abrigo do Lagar Velho]] rock-shelter site in Portugal in 1999 further supports the multiregional hypothesis, by reflecting the admixture of diverse human populations<ref>''The early Upper Paleolithic human skeleton from the Abrigo do Lagar Velho (Portugal) and modern human emergence in Iberia'' ;Duarte C, 2. Maurício J, Pettitt P, Souto P, Trinkaus E, van der Plicht H, Zilhão J (1999) Proc Natl Acad Sci USA 96:7604–7609,[http://www.pnas.org/content/96/13/7604.abstract?ijkey=9335ab52731624a02b5f7f426c4a8c2147934993&keytype2=tf_ipsecsha]</ref>. Two other archaeologists dispute this: "the analysis by Duarte ''et al.'' of the Lagar Velho child's skeleton is a brave and imaginative interpretation, of which it is unlikely that a majority of paleoanthropologists will consider proven."<ref>''Chunky Gravettian child''; Ian Tattersall and Jeffrey H. Schwartz .[http://www.pnas.org/cgi/content/full/96/13/7117]</ref> |
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==Fossil evidence == |
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Studies on past [[population bottleneck]]s that can be inferred from molecular data have led Multiregionalists to conclude that the [[recent single-origin hypothesis]] is untenable because there are no population size bottlenecks affecting all genes that are more recent than the one at the beginning of the species, some 2 million years ago. Multiregionalists claimed that the discovery of a possible hybrid ''Homo sapiens X neanderthalensis'' fossil child at the [[Abrigo do Lagar Velho]] rock-shelter site in Portugal in 1999 further supports the Multiregional hypothesis, by reflecting the inter-mixture of diverse human populations<ref>''The early Upper Paleolithic human skeleton from the Abrigo do Lagar Velho (Portugal) and modern human emergence in Iberia'' ;Duarte C, 2. Maurício J, Pettitt P, Souto P, Trinkaus E, van der Plicht H, Zilhão J (1999) Proc Natl Acad Sci USA 96:7604–7609,[http://www.pnas.org/content/96/13/7604.abstract?ijkey=9335ab52731624a02b5f7f426c4a8c2147934993&keytype2=tf_ipsecsha]</ref>. Two other archaeologists dispute this: "the analysis by Duarte ''et al.'' of the Lagar Velho child's skeleton is a brave and imaginative interpretation, of which it is unlikely that a majority of paleoanthropologists will consider proven." <ref>''Chunky Gravettian child''; Ian Tattersall and Jeffrey H. Schwartz .[http://www.pnas.org/cgi/content/full/96/13/7117]</ref> |
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In an article appearing in the [[Proceedings of the National Academy of Sciences]]<ref>http://www.pnas.org/cgi/content/abstract/104/18/7367 European early modern humans and the fate of the Neandertals</ref> in 2007, Erik Trinkaus has brought together the available data, which shows that early modern humans did exhibit evidence of Neandertal traits. |
In an article appearing in the [[Proceedings of the National Academy of Sciences]]<ref>http://www.pnas.org/cgi/content/abstract/104/18/7367 European early modern humans and the fate of the Neandertals</ref> in 2007, Erik Trinkaus has brought together the available data, which shows that early modern humans did exhibit evidence of Neandertal traits. |
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<ref>http://www.sciencedaily.com/releases/2007/04/070423185434.htm The Emerging Fate Of The Neandertals</ref> |
<ref>http://www.sciencedaily.com/releases/2007/04/070423185434.htm The Emerging Fate Of The Neandertals</ref> |
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Proponents of the multiregional hypothesis point to a recent Australian study of an ancient Aboriginal skeleton known as [[Mungo Man]]. Genetic tests show the mitochondrial DNA of Mungo Man to be from a [[Human mitochondrial DNA haplogroup|mtDNA lineage]] with no descendants today. Yet Mungo man is an [[anatomically modern human]] and has been dated to be at least 40,000 years old. These proponents interpret the study to mean that mtDNA does not reflect ancestry or [[divergence]] times |
Proponents of the multiregional hypothesis point to a recent Australian study of an ancient Aboriginal skeleton known as [[Mungo Man]]. Genetic tests show the mitochondrial DNA of Mungo Man to be from a [[Human mitochondrial DNA haplogroup|mtDNA lineage]] with no descendants today. Yet Mungo man is an [[anatomically modern human]] and has been dated to be at least 40,000 years old. These proponents interpret the study to mean that mtDNA does not reflect ancestry or [[divergence]] times.{{fact}}{{clarify me}} |
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A recent, non-fossilized discovery of one metre-tall, small-brained (350 [[cubic centimeter|cc]]), ''[[Homo floresiensis]]'', on the Indonesian island of [[Flores]], might imply populations of ''[[Homo erectus]]'' survived very late, and gave rise to even later, physically dwarfed isolated "erectus" groups. However, this possibility does not address the |
A recent, non-fossilized discovery of one metre-tall, small-brained (350 [[cubic centimeter|cc]]), ''[[Homo floresiensis]]'', on the Indonesian island of [[Flores]], might imply populations of ''[[Homo erectus]]'' survived very late, and gave rise to even later, physically dwarfed isolated "erectus" groups. However, this possibility does not address the multiregional hypothesis, which is only about the human species, and the evidence is marred by the possibility that the single dwarf cranium found on Flores might have been pathological.{{OR}} |
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==Genetic evidence== |
==Genetic evidence== |
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Proponents of the |
Proponents of the multiregional or hybrid-origin hypothesis point to the study of temporally separated genetic lineages on the scale of 1MYA, and interpret it as genetic evidence for inter-breeding between 'humans' and other 'hominids'.{{Clarify me|date=May 2009}} |
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*[[Microcephalin]].<ref>Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage; PNAS | November 28, 2006 | vol. 103 | no. 48 | 18178-18183 ; quote: "... As such, microcephalin shows by far the most compelling evidence of admixture among the human loci examined thus far. Speculation about the identity of the archaic Homo population from which the microcephalin D allele introgressed into the modern human gene pool '''points to the Neanderthal lineage''' as a potential (although by no means only) candidate. Anatomically modern humans and Neanderthals shared a long period of coexistence, from as early as 130,000 years ago in the Middle East (39) to as late as 35,000 years ago in Europe (40), consistent with the estimated introgression time of the microcephalin D allele at or sometime before {approx}37,000 years ago. Furthermore, the worldwide frequency distribution of the D allele, exceptionally high outside of Africa but low in sub-Saharan Africa (29), suggests, but does not necessitate, admixture with an archaic Eurasian population. Finally, our estimate of the separation time between D and non-D alleles (i.e., {approx}1,100,000 years with a lower-bound confidence interval of {approx}530,000 years) is largely consistent with the divergence time between modern humans and Neanderthals based on mitochondrial DNA (mtDNA) sequence difference (320,000–740,000 years; refs. 41 and 42) and with the earliest appearance of Neanderthals in the fossil record {approx}500,000 years ago (43). It would be of great interest to sequence the microcephalin locus in Neanderthals or other archaic Homo lineages, should it become technically feasible to retrieve and analyze nuclear DNA from ancient hominid remains. Our results not only provide genetic evidence in support of the possibility of admixture between modern humans and an archaic Homo lineage but also support the notion that the biological evolution of modern humans might have benefited from the contribution of adaptive alleles from our archaic relatives. In the case of microcephalin, it is all the more intriguing given the fact that the adaptive allele is associated with an important brain development gene. ..." URL:http://www.pnas.org/cgi/content/full/103/48/18178</ref><ref>http://www.pnas.org/cgi/content/full/104/18/7367</ref><ref>Microcephalin, a Gene Regulating Brain Size, Continues to Evolve Adaptively in Humans; Science 9 September 2005: Vol. 309. no. 5741, pp. 1717 - 1720 DOI: 10.1126/science.1113722; Patrick D. Evans & all; URL:http://www.sciencemag.org/cgi/content/full/309/5741/1717 </ref> |
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*[[Microcephalin]].<ref> |
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*RRM2P4 region on [[X chromosome]].<ref>''Testing for Archaic Hominin Admixture on the X Chromosome: Model Likelihoods for the Modern Human RRM2P4 Region From Summaries of Genealogical Topology Under the Structured Coalescent''. Murray P. Cox Genetics, Vol. 178, 427-437, January 2008, doi:10.1534/genetics.107.080432 URL: http://www.genetics.org/cgi/content/full/178/1/427</ref> |
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Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage; |
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*PDHA1 locus on X chromosome.<ref>More on the X files. Rosalind M. Harding. PNAS Vol. 96, Issue 6, 2582-2584, March 16, 1999 http://www.pnas.org/cgi/content/full/96/6/2582; quote:''the pattern of diversity at the PDHA1 locus unexpected is that this extreme structure is observed in a polymorphism with an estimated total coalescent-time depth of 1.86 million years''</ref> |
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==Researchers== |
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PNAS | November 28, 2006 | vol. 103 | no. 48 | 18178-18183 ; |
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The most prominent current proponents of the multiregional hypothesis are [[Milford H. Wolpoff]], Wu Xinzhi, Alan G. Thorne, James Calcagno<ref>[http://www.luc.edu/depts/anthropology/jmc/calcagno.html Calcagno homepage link]</ref>, John Hawks<ref>[http://www.johnhawks.net John Hawks homepage link]</ref> and [[Erik Trinkaus]]. |
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quote: "... As such, microcephalin shows by far the most compelling evidence of admixture among the human loci examined thus far. |
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Speculation about the identity of the archaic Homo population from which the microcephalin D allele introgressed into the modern human gene pool '''points to the Neanderthal lineage''' as a potential (although by no means only) candidate. Anatomically modern humans and Neanderthals shared a long period of coexistence, from as early as 130,000 years ago in the Middle East (39) to as late as 35,000 years ago in Europe (40), consistent with the estimated introgression time of the microcephalin D allele at or sometime before {approx}37,000 years ago. Furthermore, the worldwide frequency distribution of the D allele, exceptionally high outside of Africa but low in sub-Saharan Africa (29), suggests, but does not necessitate, admixture with an archaic Eurasian population. Finally, our estimate of the separation time between D and non-D alleles (i.e., {approx}1,100,000 years with a lower-bound confidence interval of {approx}530,000 years) is largely consistent with the divergence time between modern humans and Neanderthals based on mitochondrial DNA (mtDNA) sequence difference (320,000–740,000 years; refs. 41 and 42) and with the earliest appearance of Neanderthals in the fossil record {approx}500,000 years ago (43). It would be of great interest to sequence the microcephalin locus in Neanderthals or other archaic Homo lineages, should it become technically feasible to retrieve and analyze nuclear DNA from ancient hominid remains. |
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Our results not only provide genetic evidence in support of the possibility of admixture between modern humans and an archaic Homo lineage but also support the notion that the biological evolution of modern humans might have benefited from the contribution of adaptive alleles from our archaic relatives. In the case of microcephalin, it is all the more intriguing given the fact that the adaptive allele is associated with an important brain development gene. ..." URL:http://www.pnas.org/cgi/content/full/103/48/18178</ref><ref> |
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URL: http://www.pnas.org/cgi/content/full/104/18/7367</ref><ref> |
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Microcephalin, a Gene Regulating Brain Size, Continues to Evolve Adaptively in Humans; |
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Science 9 September 2005: Vol. 309. no. 5741, pp. 1717 - 1720 DOI: 10.1126/science.1113722; |
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Patrick D. Evans & all; |
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URL:http://www.sciencemag.org/cgi/content/full/309/5741/1717 </ref> |
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*RRM2P4 region on [[X chromosome]].<ref> |
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''Testing for Archaic Hominin Admixture on the X Chromosome: Model Likelihoods for the Modern Human RRM2P4 Region From Summaries of Genealogical Topology Under the Structured Coalescent'' |
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Murray P. Cox |
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Genetics, Vol. 178, 427-437, January 2008, Copyright © 2008 |
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doi:10.1534/genetics.107.080432 |
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URL: http://www.genetics.org/cgi/content/full/178/1/427</ref> |
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*PDHA1 locus on X chromosome.<ref> |
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More on the X files |
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Rosalind M. Harding |
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PNAS Vol. 96, Issue 6, 2582-2584, March 16, 1999 |
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http://www.pnas.org/cgi/content/full/96/6/2582 |
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quote:''the pattern of diversity at the PDHA1 locus unexpected is that this extreme structure is observed in a polymorphism with an estimated total coalescent-time depth of 1.86 million years''</ref> |
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==Hybrid-origin theory== |
==Hybrid-origin theory== |
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{{mergefrom|Hybrid-origin|date=May 2009}} |
{{mergefrom|Hybrid-origin|date=May 2009}} |
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{{see|Hybrid-origin|Interbreeding of Cro-Magnon and Neanderthals}} |
{{see|Hybrid-origin|Interbreeding of Cro-Magnon and Neanderthals}} |
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The [[hybrid (biology)|hybrid]]-origin hypothesis of [[human origin]]s argues that all or at least some of the [[genetic variation]] between the contemporary human races is attributable to genetic inheritance from at least two widely divergent [[Hominidae|hominid]] [[species]], or [[subspecies]], that were geographically dispersed throughout [[Africa]], [[Southeast Asia]] and the [[Indian subcontinent]], prior to the evolution of modern [[human|Homo sapiens sapiens]] (according to hybrid-origin theory, approximately 35,000 years ago). |
The [[hybrid (biology)|hybrid]]-origin hypothesis of [[human origin]]s argues that all or at least some of the [[genetic variation]] between the contemporary human races is attributable to genetic inheritance from at least two widely divergent [[Hominidae|hominid]] [[species]], or [[subspecies]], that were geographically dispersed throughout [[Africa]], [[Southeast Asia]] and the [[Indian subcontinent]], prior to the evolution of modern [[human|Homo sapiens sapiens]] (according to hybrid-origin theory, approximately 35,000 years ago). [[Hominid]] populations, put forward by the hybrid-origin theory as sources for genetic admixture, include [[Neanderthal|Homo neanderthalensis]] and [[Peking Man]]. According to this theory the resulting hybrid 'Homo sapiens sapiens', was superior to both its ancestors due to what is commonly termed [[heterosis|hybrid vigour]]. This theory was first introduced in 1971 by the [[United Kingdom|British]] psychologist [[Stan Gooch]].<ref>Gooch, ''Guardians of the Ancient Wisdom'' 1979</ref> |
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==Criticism of the multiregional hypothesis== |
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[[Hominid]] populations, put forward by the hybrid-origin theory as sources for genetic admixture, include [[Neanderthal|Homo neanderthalensis]] and [[Peking Man]] (a subspecies of [[Homo erectus]]), and [[Cro-Magnon]] man (who physically and culturally differs significantly from Homo erectus). |
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This theory was first introduced in 1971 by the [[United Kingdom|British]] psychologist [[Stan Gooch]]. |
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Here is a brief summary of Gooch's theory (from ''Guardians of the Ancient Wisdom'' 1979): |
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# From other human species, Cro-Magnon man evolves in Northern India during millions of years of isolation, develops and practices sun worship and hunting magic; the culture is patriarchal. |
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# Elsewhere during the same period, different forms of Neanderthal evolve in [[Europe]] and the [[Middle East]], while moon worship and earth magic is developed and practiced; the culture is matriarchal. |
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# Around 35,000 years b.p. Cro-Magnon abandons India and heads west through the Middle East into Europe, overrunning Neanderthal. By 25,000 years ago, the predominant type in Europe is Cro-Magnon. |
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# In the Middle East a hybrid population, a cross between the Cro-Magnon and Neanderthal types, emerges. Pure Neanderthal has largely ceased to exist either here or in Europe. |
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# By 15,000 years ago, pure Cro-Magnon man has also ceased to exist, driven out of north and west Europe, into southern Europe, by renewed glaciation, absorbed by the hybrid type (that is, ourselves). |
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Meanwhile mixed types have also migrated back into Africa (during glaciation in Europe the [[Sahara]] had become well-watered, grassy plains) and back into India and then on to China. In these places the mixed type further mingled with the local Neanderthal types. |
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According to this theory the resulting hybrid 'Homo sapiens sapiens', was superior to both its ancestors due to what is commonly termed [[heterosis|hybrid vigour]]. |
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==Criticism of Multiregionalism== |
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Multiregional evolution contrasts with the "[[Recent African Origin]]" (RAO) theory. According to the latter theory, human evolution was a consequence of many cases of species replacement, as newer species replaced older ones across the human range. Modern [[human origins]], according to the RAO, is the most recent example of species replacement. |
Multiregional evolution contrasts with the "[[Recent African Origin]]" (RAO) theory. According to the latter theory, human evolution was a consequence of many cases of species replacement, as newer species replaced older ones across the human range. Modern [[human origins]], according to the RAO, is the most recent example of species replacement. |
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Multiregionalists have long claimed that modern Europeans are descended from the Neanderthals. In 1997, testing performed on mitochondrial DNA extracted from a Neanderthal skeleton showed modern humans and Neanderthals last shared a common ancestor between 500,000 and 800,000 years ago, and furthermore that all modern humans, from the ethnic Siberians to the [[!Kung people]] of Africa, are more closely related to each other than to the Neanderthals -- further evidence supporting the Out-of-Africa theory{{Fact|date=June 2008}}. But ancient lineages, dating to over 1 Mya, in [[nuclear DNA]] has been detected (see genetic evidence above).{{Clarify me|date=May 2009}} |
Multiregionalists have long claimed that modern Europeans are descended from the Neanderthals. In 1997, testing performed on mitochondrial DNA extracted from a Neanderthal skeleton showed modern humans and Neanderthals last shared a common ancestor between 500,000 and 800,000 years ago, and furthermore that all modern humans, from the ethnic Siberians to the [[!Kung people]] of Africa, are more closely related to each other than to the Neanderthals -- further evidence supporting the Out-of-Africa theory{{Fact|date=June 2008}}. But ancient lineages, dating to over 1 Mya, in [[nuclear DNA]] has been detected (see genetic evidence above).{{Clarify me|date=May 2009}} |
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[[Peking man]] (also known as "Beijing man"), a [[Homo erectus]] fossil skull (possibly dated to 500,000 years ago) found in China, provides putative evidence supporting the Multiregional Theory. Some paleoanthropologists in China have asserted that the modern Chinese are descendants of earlier forms of humans such as Peking Man. However criticism is based on genetic evidence from mtDNA. [[Microsatellite]] analysis on the Chinese populations in 1998 showed genetic similarities with Africans, yielding the first evidence the Chinese population is matrilineal from Africa. |
[[Peking man]] (also known as "Beijing man"), a [[Homo erectus]] fossil skull (possibly dated to 500,000 years ago) found in China, provides putative evidence supporting the Multiregional Theory. Some paleoanthropologists in China have asserted that the modern Chinese are descendants of earlier forms of humans such as Peking Man. However criticism is based on genetic evidence from mtDNA. [[Microsatellite]] analysis on the Chinese populations in 1998 showed genetic similarities with Africans, yielding the first evidence the Chinese population is matrilineal from Africa.<ref name=people>[http://www.people.com.cn/GB/paper81/5250/550425.html 中国人可能起源于非洲又有新证据 (New Evidence Proves that Chinese People Possibly Came from Africa)], ''大地'' 2001 No.20, available at ''[[People's Daily Online]]''. {{zh}}</ref> A recent study undertaken by [[Jin Li]] showed no inter-breeding between modern human immigrants to East Asia and ''Homo erectus'', contradicting the Peking Man-origin hypothesis and affirming that the Chinese descended from Africans.<ref>[http://calvin.linfield.edu/~mrobert/origins.htm multiregional or single origin.]</ref><ref>[http://www.amazon.com/gp/reader/0618091572 mapping human history p130-131]</ref> In 2001, Chinese geneticists analyzed Y chromosomes in Chinese people and concluded that all Chinese samples contained a mutated gene M168G which is a marker believed to have appeared in the last 79,000 years in an African population.<ref name=people/> |
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==History== |
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===Polygenism=== |
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{{main|Polygenism}} |
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An older theory is Polygenic evolution, a multiple origins theory in which the different human populations or races had independent origins and evolved in isolation from each other. It was held by many scholars of the 19th century such as Haeckel and Klaatsch. [[Polygenism]] is sometimes mistaken for Multiregional evolution, because they are both hypotheses of evolution within a single species. However, Polygenic evolution depends on isolation of populations while Multiregional evolution requires population interactions and interbreeding so that genetic changes can spread throughout the human range, especially when they are promoted by natural selection. According to the Multiregional hypothesis, geographic differences between human populations are the results of [[climate change|climatic variation]], [[Geographical isolation|isolation by distance]], [[sexual selection]], and historical accidents ([[genetic drift]]). |
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===Weidenreich-Coon=== |
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The Multiregional Hypothesis has its origin in the work of [[Franz Weidenreich]] in the 1930s. At that time, Weidenreich originated the "Weidenreich Theory of Human Evolution" based on his examination of Peking Man. Weidenreich was an anatomist and observed numerous anatomical characteristics that Peking Man had in common with modern [[Asian people|Asians]]. The Weidenreich Theory stated that human races have evolved independently in the [[Old World]] from [[Homo erectus]] to [[Homo sapiens|Homo sapiens sapiens]], while at the same time there was gene flow between the various populations. According to the theory proposed by Weidenreich, genes that were generally adaptive (such as those for intelligence) flowed relatively rapidly from one part of the world to the other, while those that were locally adaptive, would not. This is the direct opposite to theories of human evolution that have been popularized in the [[Mass media|press]] with one superior race (e.g. Modern Humans) displacing other races (e.g. [[Neanderthal]]s). A vocal proponent of the Weidenreich theory was [[Carleton S. Coon|Carleton Coon]]. |
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==Regional Continuity (Wolpoff)== |
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The term "multiregional hypothesis" was first coined in the early 1980s by [[Milford H. Wolpoff]] and a group of associates as an explanation for the apparent similarities of the remains from the ''[[Homo erectus]]'' and ''[[Homo sapiens]]'' inhabiting the same region. This phenomenon was termed '''regional continuity''' and baffled the scientists at first. These scientists explained the apparent regional continuity by claiming Homo erectus and Homo sapiens were the same species and there had been just enough interbreeding to cause an overall global development towards the latter, but without stamping out the regional adaptation that had been developed by the former. Such a delicate balance seemed unlikely and puzzled the [[anthropologists]]. |
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Eventually, Milford H. Wolpoff proposed an explanation based on [[cline (population genetics)|clinal variation]] that would allow for the necessary balance. This was the multiregional hypothesis. It theorizes that Homo erectus, Neanderthals, Homo sapiens and other humans were a single species. This species arose in Africa two million years ago as Homo erectus and then spread out over the world, developing adaptations to regional conditions. |
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For periods of time some populations became isolated, developing in a different direction. But through a complicated process involving continuous interbreeding, replacement, [[genetic drift]] and other vehicles of [[evolution]], adaptations that were an advantage anywhere on earth would spread, keeping the development of the species in the same overall direction, while maintaining adaptations to regional factors. |
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Eventually, the more unusual local varieties of the species would have disappeared in favor of modern humans while retaining some regional adaptations, but also with many common features. |
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==Implications== |
==Implications== |
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[[Leonard Lieberman]] and [[Fatimah Jackson]] have suggested that any new support for a biological concept of race will likely come from another source, namely, the study of human evolution. They therefore ask what, if any, implications current models of human evolution may have for any biological conception of race.<ref>Leonard Lieberman and Fatimah Linda C. Jackson (1995) "Race and Three Models of Human Origin" in ''American Anthropologist'' Vol. 97, No. 2, pp. 232-234</ref> |
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Today, all [[humans]] are classified as belonging to the species ''Homo sapiens'' and sub-species ''Homo sapiens sapiens.'' However, this is not the first species of hominids: the first species of genus ''Homo'', [[Homo habilis]], evolved in East Africa at least 2 million years ago, and members of this species populated different parts of Africa in a relatively short time. ''[[Homo erectus]]'' evolved more than 1.8 million years ago, and by 1.5 million years ago had spread throughout the Old World. Virtually all physical anthropologists agree that ''Homo sapiens'' evolved out of ''Homo erectus.'' Anthropologists have been divided as to whether ''Homo sapiens'' evolved as one interconnected species from ''H. erectus'' (called the Multiregional Model, or the Regional Continuity Model), or evolved only in East Africa, and then migrated out of Africa and replaced ''H. erectus'' populations throughout the Old World (called the Out of Africa Model or the Complete Replacement Model). Anthropologists continue to debate both possibilities, and the evidence is technically ambiguous as to which model is correct, although most anthropologists currently favor the Out of Africa model. |
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Advocates of the Multiregional model, primarily [[Milford Wolpoff]] and his associates, have argued that the simultaneous evolution of ''H. sapiens'' in different parts of Europe and Asia would have been possible if there were a degree of [[gene flow]] between archaic populations.<ref>Thorne, Alan, and Milford Wolpoff (1992) "The Multiregional Evolution of humans" in ''Scientific American, April 76-93; Smith, Fred and [[Frank Spencer (anthropologist)|]], eds (1984) ''The Origin of Modern Humans''</ref> Similarities of morphological features between archaic European and Chinese populations and modern ''H. sapiens'' from the same regions, Wolpoff argues, support a regional continuity only possible within the Multiregional model.<ref>Robert H. Lavenda and Emily A. Shultz ''Anthropology, what does it mean to be human?'' Oxford (New York:2008) 132.</ref> Wolpoff and others further argue that this model is consistent with [[Cline (population genetics)|clinal patterns]] of phenotypic variation (Wolpoff 1993). Lieberman and Jackson have related this theory to race with the following statement: |
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{{cquote|The major implication for race in the multiregional evolution continuity model involves the time depth of a million or more years in which race differentiation might evolve in diverse ecological regions [...]. This must be balanced against the degree of gene flow and the transregional operation of natural selection on encephalization due to development of tools and, more broadly, culture.<ref>Leonard Lieberman and Fatimah Linda C. Jackson (1995) "Race and Three Models of Human Origin" in ''American Anthropologist'' Vol. 97, No. 2, pp. 237</ref>}} |
{{cquote|The major implication for race in the multiregional evolution continuity model involves the time depth of a million or more years in which race differentiation might evolve in diverse ecological regions [...]. This must be balanced against the degree of gene flow and the transregional operation of natural selection on encephalization due to development of tools and, more broadly, culture.<ref>Leonard Lieberman and Fatimah Linda C. Jackson (1995) "Race and Three Models of Human Origin" in ''American Anthropologist'' Vol. 97, No. 2, pp. 237</ref>}} |
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==References== |
==References== |
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{{refimprove}} |
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{{reflist}} |
{{reflist}} |
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==External links== |
==External links== |
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{{External links}} |
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* [http://www.physorg.com/news10534.html New analysis shows three human migrations out of Africa] "The 'Out of Africa' replacement theory has always been a big controversy," Templeton said. "I set up a null hypothesis and the program rejected that hypothesis using the new data with a probability level of 10 to the minus 17th. In science, you don't get any more conclusive than that. It says that the hypothesis of no interbreeding is so grossly incompatible with the data, that you can reject it." |
* [http://www.physorg.com/news10534.html New analysis shows three human migrations out of Africa] "The 'Out of Africa' replacement theory has always been a big controversy," Templeton said. "I set up a null hypothesis and the program rejected that hypothesis using the new data with a probability level of 10 to the minus 17th. In science, you don't get any more conclusive than that. It says that the hypothesis of no interbreeding is so grossly incompatible with the data, that you can reject it." |
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* [http://harpend.dsl.xmission.com/Documents/eswaran%20et%20al%202005%20genomics%20refutes%20exclusively%20african%20origin%20jhe.pdf] - 'Genomics refutes an exclusively African origin of humans' (pdf) Vinayak Eswaran, Henry Harpending, Alan R. Rogers, Journal of Human Evolution (2005) |
* [http://harpend.dsl.xmission.com/Documents/eswaran%20et%20al%202005%20genomics%20refutes%20exclusively%20african%20origin%20jhe.pdf] - 'Genomics refutes an exclusively African origin of humans' (pdf) Vinayak Eswaran, Henry Harpending, Alan R. Rogers, Journal of Human Evolution (2005) |
Revision as of 20:37, 29 May 2009
In paleoanthropology, the multiregional hypothesis is a theory of the origin of anatomically modern humans, Homo sapiens sapiens. The multiregional hypothesis holds that the evolution of humanity throughout the Pleistocene (1.8 million to 10,000 years before present) has been within a single, continuous human species, evolving worldwide from Homo erectus to modern Homo sapiens.[1]
A competing theory of the recent African origin of modern humans (also known as "Out of Africa") has emerged as the near consensus view since the 1990s,[2][3] proposing that modern humans arose in Africa around 100-200,000 years ago, moving out of Africa around 50-60,000 years ago to replace existing human species such as Homo erectus and the Neanderthals.[4]
Advocates of the multiregional hypothesis point to some recent genetic data|^[5] as support for their hypothesis, and some interbreeding (or "admixture") between modern humans and previous human species has not been ruled out,[6][7] although it is increasingly unlikely for Neanderthals.[8][9] To differentiate between early historical, unscientific conceptions some researchers prefer to use term multiregional evolution instead of multiregional hypothesis of human evolution.
History
Polygenism
An older theory is polygenic evolution, a multiple origins theory in which the different human populations or races had independent origins and evolved in isolation from each other. It was held by many scholars of the 19th century such as Haeckel and Klaatsch. Polygenism is sometimes mistaken for multiregional evolution, because they are both hypotheses of evolution within a single species. However, polygenic evolution depends on isolation of populations while multiregional evolution requires population interactions and interbreeding so that genetic changes can spread throughout the human range, especially when they are promoted by natural selection. According to the multiregional hypothesis, geographic differences between human populations are the results of climatic variation, isolation by distance, sexual selection, and historical accidents (genetic drift).
Weidenreich-Coon
The multiregional hypothesis has its origin in the work of Franz Weidenreich in the 1930s. At that time, Weidenreich originated the "Weidenreich Theory of Human Evolution" based on his examination of Peking Man. Weidenreich was an anatomist and observed numerous anatomical characteristics that he thought Peking Man had in common with modern Asians. The Weidenreich Theory stated that human races have evolved independently in the Old World from Homo erectus to Homo sapiens sapiens, while at the same time there was gene flow between the various populations. According to the theory proposed by Weidenreich, genes that were generally adaptive (such as those for intelligence) flowed relatively rapidly from one part of the world to the other, while those that were locally adaptive, would not. A vocal proponent of the Weidenreich theory was Carleton Coon.
Regional continuity
The term "multiregional hypothesis" was first coined in the early 1980s by Milford H. Wolpoff and a group of associates as an explanation for the apparent similarities of the remains from the Homo erectus and Homo sapiens inhabiting the same region, what they called regional continuity.
Wolpoff proposed an explanation based on clinal variation that would allow for the necessary balance. He proposed that Homo erectus, Neanderthals, Homo sapiens and other humans were a single species. This species arose in Africa two million years ago as H. erectus and then spread out over the world, developing adaptations to regional conditions. It was proposed that for periods of time some populations became isolated, developing in a different direction, but through continuous interbreeding, replacement, genetic drift and other vehicles of evolution, adaptations that were an advantage anywhere on earth would spread, keeping the development of the species in the same overall direction, while maintaining adaptations to regional factors. Eventually, the more unusual local varieties of the species would have disappeared in favor of modern humans while retaining some regional adaptations, but also with many common features.
Classification of hominid species
Evaluation of the multiregional theory revolves around the assumption or non-assumption of species barriers between early hominids. Because of the scarcity of fossils and the discovery of important new finds every few years, researchers disagree about the details and sometimes even basic elements of human evolutionary history. While they have revised this history several times over the last decades, researchers currently agree that the oldest named species of the genus Homo, Homo habilis, evolved in Africa around two million years ago, and that members of the genus migrated out of Africa somewhat later, at least 1.5 million years ago. The descendants of these ancient migrants, which probably included Homo erectus, have become known through fossils uncovered far from Africa, such as those of "Peking man" and "Java man". Homo neanderthalensis is also considered a descendant of early migrants.
Fossil evidence
Studies on past population bottlenecks that can be inferred from molecular data have led multiregionalists to conclude that the recent single-origin hypothesis is untenable because there are no population size bottlenecks affecting all genes that are more recent than the one at the beginning of the species, some 2 million years ago. Multiregionalists claimed that the discovery of a possible hybrid Homo sapiens X neanderthalensis fossil child at the Abrigo do Lagar Velho rock-shelter site in Portugal in 1999 further supports the multiregional hypothesis, by reflecting the admixture of diverse human populations[10]. Two other archaeologists dispute this: "the analysis by Duarte et al. of the Lagar Velho child's skeleton is a brave and imaginative interpretation, of which it is unlikely that a majority of paleoanthropologists will consider proven."[11]
In an article appearing in the Proceedings of the National Academy of Sciences[12] in 2007, Erik Trinkaus has brought together the available data, which shows that early modern humans did exhibit evidence of Neandertal traits. "When you look at all of the well dated and diagnostic early modern European fossils, there is a persistent presence of anatomical features that were present among the Neandertals but absent from the earlier African modern humans," Trinkaus said. "Early modern Europeans reflect both their predominant African early modern human ancestry and a substantial degree of admixture between those early modern humans and the indigenous Neandertals." [13]
Proponents of the multiregional hypothesis point to a recent Australian study of an ancient Aboriginal skeleton known as Mungo Man. Genetic tests show the mitochondrial DNA of Mungo Man to be from a mtDNA lineage with no descendants today. Yet Mungo man is an anatomically modern human and has been dated to be at least 40,000 years old. These proponents interpret the study to mean that mtDNA does not reflect ancestry or divergence times.[citation needed][clarification needed]
A recent, non-fossilized discovery of one metre-tall, small-brained (350 cc), Homo floresiensis, on the Indonesian island of Flores, might imply populations of Homo erectus survived very late, and gave rise to even later, physically dwarfed isolated "erectus" groups. However, this possibility does not address the multiregional hypothesis, which is only about the human species, and the evidence is marred by the possibility that the single dwarf cranium found on Flores might have been pathological.[original research?]
Genetic evidence
Proponents of the multiregional or hybrid-origin hypothesis point to the study of temporally separated genetic lineages on the scale of 1MYA, and interpret it as genetic evidence for inter-breeding between 'humans' and other 'hominids'.[clarification needed]
- RRM2P4 region on X chromosome.[17]
- PDHA1 locus on X chromosome.[18]
Researchers
The most prominent current proponents of the multiregional hypothesis are Milford H. Wolpoff, Wu Xinzhi, Alan G. Thorne, James Calcagno[19], John Hawks[20] and Erik Trinkaus.
Hybrid-origin theory
The hybrid-origin hypothesis of human origins argues that all or at least some of the genetic variation between the contemporary human races is attributable to genetic inheritance from at least two widely divergent hominid species, or subspecies, that were geographically dispersed throughout Africa, Southeast Asia and the Indian subcontinent, prior to the evolution of modern Homo sapiens sapiens (according to hybrid-origin theory, approximately 35,000 years ago). Hominid populations, put forward by the hybrid-origin theory as sources for genetic admixture, include Homo neanderthalensis and Peking Man. According to this theory the resulting hybrid 'Homo sapiens sapiens', was superior to both its ancestors due to what is commonly termed hybrid vigour. This theory was first introduced in 1971 by the British psychologist Stan Gooch.[21]
Criticism of the multiregional hypothesis
Multiregional evolution contrasts with the "Recent African Origin" (RAO) theory. According to the latter theory, human evolution was a consequence of many cases of species replacement, as newer species replaced older ones across the human range. Modern human origins, according to the RAO, is the most recent example of species replacement.
Aspects of multiregionalism have been criticized as not being based on objective scientific observation. Some critics even argue that multiregionalism may be motivated by ethnocentrism and is meant to instill beliefs of purity of lineage.
Multiregionalists have long claimed that modern Europeans are descended from the Neanderthals. In 1997, testing performed on mitochondrial DNA extracted from a Neanderthal skeleton showed modern humans and Neanderthals last shared a common ancestor between 500,000 and 800,000 years ago, and furthermore that all modern humans, from the ethnic Siberians to the !Kung people of Africa, are more closely related to each other than to the Neanderthals -- further evidence supporting the Out-of-Africa theory[citation needed]. But ancient lineages, dating to over 1 Mya, in nuclear DNA has been detected (see genetic evidence above).[clarification needed]
Peking man (also known as "Beijing man"), a Homo erectus fossil skull (possibly dated to 500,000 years ago) found in China, provides putative evidence supporting the Multiregional Theory. Some paleoanthropologists in China have asserted that the modern Chinese are descendants of earlier forms of humans such as Peking Man. However criticism is based on genetic evidence from mtDNA. Microsatellite analysis on the Chinese populations in 1998 showed genetic similarities with Africans, yielding the first evidence the Chinese population is matrilineal from Africa.[22] A recent study undertaken by Jin Li showed no inter-breeding between modern human immigrants to East Asia and Homo erectus, contradicting the Peking Man-origin hypothesis and affirming that the Chinese descended from Africans.[23][24] In 2001, Chinese geneticists analyzed Y chromosomes in Chinese people and concluded that all Chinese samples contained a mutated gene M168G which is a marker believed to have appeared in the last 79,000 years in an African population.[22]
Implications
Leonard Lieberman and Fatimah Jackson have suggested that any new support for a biological concept of race will likely come from another source, namely, the study of human evolution. They therefore ask what, if any, implications current models of human evolution may have for any biological conception of race.[25]
The major implication for race in the multiregional evolution continuity model involves the time depth of a million or more years in which race differentiation might evolve in diverse ecological regions [...]. This must be balanced against the degree of gene flow and the transregional operation of natural selection on encephalization due to development of tools and, more broadly, culture.[26]
References
- ^ Wolpoff, MH (2000). "Multiregional, not multiple origins". Am J Phys Anthropol. 112 (1): 129–36.
{{cite journal}}
: Unknown parameter|coauthors=
ignored (|author=
suggested) (help) - ^ Hua Liu, et al. A Geographically Explicit Genetic Model of Worldwide Human-Settlement History. American Journal of Human Genetics, volume 79 (2006), pages 230–237, quote: Currently available genetic and archaeological evidence is generally interpreted as supportive of a recent single origin of modern humans in East Africa. However, this is where the near consensus on human settlement history ends, and considerable uncertainty clouds any more detailed aspect of human colonization history.
- ^ Weaver, Timothy D (2008). "New developments in the genetic evidence for modern human origins". Evolutionary Anthropology: Issues, News, and Reviews. 17 (1). Wiley-Liss: 69–80.
{{cite journal}}
: Unknown parameter|coauthors=
ignored (|author=
suggested) (help) - ^ Fagundes, NJ (2007). "Statistical evaluation of alternative models of human evolution". Proc Natl Acad Sci U S A. 104 (45): 17614–9.
{{cite journal}}
: Unknown parameter|coauthors=
ignored (|author=
suggested) (help) - ^ Cox, MP (2008). "Testing for archaic hominin admixture on the X chromosome: model likelihoods for the modern human RRM2P4 region from summaries of genealogical topology under the structured coalescent". Genetics. 178 (1): 427–37.
{{cite journal}}
: Unknown parameter|coauthors=
ignored (|author=
suggested) (help) - ^ Relethford, JH (2008). "Genetic evidence and the modern human origins debate". Heredity. 100 (6). Macmillan: 555–63.
- ^ Wall, JD (2006). "Archaic admixture in the human genome". Curr Opin Genet Dev. 16 (6): 606–10.
{{cite journal}}
: Unknown parameter|coauthors=
ignored (|author=
suggested) (help) - ^ Hodgson, JA (2008). "No evidence of a Neanderthal contribution to modern human diversity". Genome Biology. 9 (2). BioMed Central: 206.
{{cite journal}}
: Unknown parameter|coauthors=
ignored (|author=
suggested) (help) - ^ Belle, EM (2009). "Comparing models on the genealogical relationships among Neandertal, Cro-Magnoid and modern Europeans by serial coalescent simulations". Heredity. 102 (3). London: Macmillan: 218–25.
{{cite journal}}
: Unknown parameter|coauthors=
ignored (|author=
suggested) (help) - ^ The early Upper Paleolithic human skeleton from the Abrigo do Lagar Velho (Portugal) and modern human emergence in Iberia ;Duarte C, 2. Maurício J, Pettitt P, Souto P, Trinkaus E, van der Plicht H, Zilhão J (1999) Proc Natl Acad Sci USA 96:7604–7609,[1]
- ^ Chunky Gravettian child; Ian Tattersall and Jeffrey H. Schwartz .[2]
- ^ http://www.pnas.org/cgi/content/abstract/104/18/7367 European early modern humans and the fate of the Neandertals
- ^ http://www.sciencedaily.com/releases/2007/04/070423185434.htm The Emerging Fate Of The Neandertals
- ^ Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage; PNAS | November 28, 2006 | vol. 103 | no. 48 | 18178-18183 ; quote: "... As such, microcephalin shows by far the most compelling evidence of admixture among the human loci examined thus far. Speculation about the identity of the archaic Homo population from which the microcephalin D allele introgressed into the modern human gene pool points to the Neanderthal lineage as a potential (although by no means only) candidate. Anatomically modern humans and Neanderthals shared a long period of coexistence, from as early as 130,000 years ago in the Middle East (39) to as late as 35,000 years ago in Europe (40), consistent with the estimated introgression time of the microcephalin D allele at or sometime before {approx}37,000 years ago. Furthermore, the worldwide frequency distribution of the D allele, exceptionally high outside of Africa but low in sub-Saharan Africa (29), suggests, but does not necessitate, admixture with an archaic Eurasian population. Finally, our estimate of the separation time between D and non-D alleles (i.e., {approx}1,100,000 years with a lower-bound confidence interval of {approx}530,000 years) is largely consistent with the divergence time between modern humans and Neanderthals based on mitochondrial DNA (mtDNA) sequence difference (320,000–740,000 years; refs. 41 and 42) and with the earliest appearance of Neanderthals in the fossil record {approx}500,000 years ago (43). It would be of great interest to sequence the microcephalin locus in Neanderthals or other archaic Homo lineages, should it become technically feasible to retrieve and analyze nuclear DNA from ancient hominid remains. Our results not only provide genetic evidence in support of the possibility of admixture between modern humans and an archaic Homo lineage but also support the notion that the biological evolution of modern humans might have benefited from the contribution of adaptive alleles from our archaic relatives. In the case of microcephalin, it is all the more intriguing given the fact that the adaptive allele is associated with an important brain development gene. ..." URL:http://www.pnas.org/cgi/content/full/103/48/18178
- ^ http://www.pnas.org/cgi/content/full/104/18/7367
- ^ Microcephalin, a Gene Regulating Brain Size, Continues to Evolve Adaptively in Humans; Science 9 September 2005: Vol. 309. no. 5741, pp. 1717 - 1720 DOI: 10.1126/science.1113722; Patrick D. Evans & all; URL:http://www.sciencemag.org/cgi/content/full/309/5741/1717
- ^ Testing for Archaic Hominin Admixture on the X Chromosome: Model Likelihoods for the Modern Human RRM2P4 Region From Summaries of Genealogical Topology Under the Structured Coalescent. Murray P. Cox Genetics, Vol. 178, 427-437, January 2008, doi:10.1534/genetics.107.080432 URL: http://www.genetics.org/cgi/content/full/178/1/427
- ^ More on the X files. Rosalind M. Harding. PNAS Vol. 96, Issue 6, 2582-2584, March 16, 1999 http://www.pnas.org/cgi/content/full/96/6/2582; quote:the pattern of diversity at the PDHA1 locus unexpected is that this extreme structure is observed in a polymorphism with an estimated total coalescent-time depth of 1.86 million years
- ^ Calcagno homepage link
- ^ John Hawks homepage link
- ^ Gooch, Guardians of the Ancient Wisdom 1979
- ^ a b 中国人可能起源于非洲又有新证据 (New Evidence Proves that Chinese People Possibly Came from Africa), 大地 2001 No.20, available at People's Daily Online.
- ^ multiregional or single origin.
- ^ mapping human history p130-131
- ^ Leonard Lieberman and Fatimah Linda C. Jackson (1995) "Race and Three Models of Human Origin" in American Anthropologist Vol. 97, No. 2, pp. 232-234
- ^ Leonard Lieberman and Fatimah Linda C. Jackson (1995) "Race and Three Models of Human Origin" in American Anthropologist Vol. 97, No. 2, pp. 237
See also
- Polygenism
- Recent single-origin hypothesis
- Punctuated equilibrium
- Interbreeding of Cro-Magnon and Neanderthals
- Mitochondrial Eve
- Y-chromosomal Adam
- Hybrid-origin
External links
- New analysis shows three human migrations out of Africa "The 'Out of Africa' replacement theory has always been a big controversy," Templeton said. "I set up a null hypothesis and the program rejected that hypothesis using the new data with a probability level of 10 to the minus 17th. In science, you don't get any more conclusive than that. It says that the hypothesis of no interbreeding is so grossly incompatible with the data, that you can reject it."
- [3] - 'Genomics refutes an exclusively African origin of humans' (pdf) Vinayak Eswaran, Henry Harpending, Alan R. Rogers, Journal of Human Evolution (2005)
- [4] - 'Templeton tree'
- [5] - 'The Hybrid Child from Portugal'
- Biochem. Soc. Trans (2005) 33, 582-585 - J. Hardy and others - Molecular Mechanisms of Neurodegeneration (Evidence suggesting that Homo neanderthalensis contributed the H2 MAPT haplotype to Homo sapiens)
- Kent Holsinger's web site - 'Drift and migration' (only 1 migrant per generation between populations of reasonable big sizes can prevent divergence in allelic frequencies)
- Genetics - 'Deep Haplotype Divergence and Long-Range Linkage Disequilibrium at Xp21.1 Provide Evidence That Humans Descend From a Structured Ancestral Population' (first genetic evidence that statistically rejects the null hypothesis that our species descends from a single, historically panmictic population), Daniel Garrigan, Zahra Mobasher, Sarah B. Kingan, Jason A. Wilder, and Michael F. Hammer, University of Arizona, Tucson, Genetics, Vol. 170, 1849-1856, August 2005
- Linfield.edu - 'The Origin of Modern Humans: Multiregional and Replacement Theories', Michael Roberts, Linfield College
- [6] - 'Evidence for Archaic Asian Ancestry on the Human X Chromosome' (suggests ancient RRM2P4 lineage is remnant of introgressive hybrid of anatomically modern humans from Africa and archaic populations in Eurasia), Daniel Garrigan, Zahra Mobasher, Tesa Severson, Jason A. Wilder, Michael F. Hammer, University of Arizona, Tucson, Molecular Biology and Evolution, vol 22, no 2, p 189-192 (2005)
- PLoS Genetics - 'Possible ancestral structure in human populations', Vincent Plagnol, Jeff D. Wall, PLoS Genetics, (2006) (evidence for ancient admixture in both a European and a West African population (p ~ 10-7), with contributions to the modern gene pool of at least 5%. While Neanderthals form an obvious archaic source population candidate in Europe, there is not yet a clear source population candidate in West Africa.)
- PNAS.org - 'Mitochondrial DNA sequences in ancient Australians: Implications for modern human origins', Gregory J. Adcock, Elizabeth S. Dennis, Simon Easteal, Gavin A. Huttley, Lars S. Jermiin, W. James Peacock, Alan Thorne, Australian National University, Proceedings of the National Academy of Sciences, vol 98, no 2, p 537-542 (January 16, 2001)
- StephenJayGould.org - 'Out of Africa vs. Multiregionalism', Tod Billings (December 7, 1999)
- TalkOrigins.org - 'The evolution of modern humans: where are we now?' Christopher B. Stringer, General Anthropology, vol 7, no 2, p 1-5 (2001)
- NYTimes.com - "Two Splits Between Human and Chimp Lines Suggested", New York Times (May 18, 2006): "The analysis, by David Reich, Nick Patterson and colleagues at the Broad Institute in Cambridge, Mass., sets up a serious conflict between the date of the split as indicated by fossil skulls, about 7 million years ago, and the much younger date implied by genetic analysis, as late as 5.4 million years ago. The conflict can be resolved, Dr. Reich's team suggests in an article published in today's Nature, if there were in fact two splits between the human and chimp lineages, with the first being followed by interbreeding between the two populations and then a second split."
- Selection, nuclear genetic variation, and mtDNA