Editing Human evolution (section)

== History of study ==
{{For timeline|Timeline of human evolution}}

=== Before Darwin ===
The name {{lang|la|Homo}} of the biological genus to which humans belong is [[Latin]] for 'human'.{{efn|The Latin word which refers to adult
males only is {{lang|la|vir}}}} It was chosen originally by [[Carl Linnaeus]] in his classification system.{{efn|See the [[Binomial nomenclature]] and {{lang|la|[[Systema Naturae]]}} articles.}} The English word ''human'' is from the Latin {{lang|la|humanus}}, the adjectival form of {{lang|la|homo}}. The Latin {{lang|la|homo}} derives from the [[Proto-Indo-European language|Indo-European]] root *''{{PIE|dhghem}}'', or 'earth'.<ref>{{cite book |title=More Word Histories and Mysteries: From Aardvark to Zombie |editor=((Editors of the American Heritage Dictionaries)) |date=2006 |location=Boston |publisher=[[Houghton Mifflin Harcourt|Houghton Mifflin]] |isbn=978-0-618-71681-4 |lccn=2006020835 |oclc=70199867 |url= https://archive.org/details/morewordhistorie0000unse |url-access=registration}}{{page needed|date=December 2021}}</ref> Linnaeus and other scientists of his time also considered the great apes to be the closest relatives of humans based on [[Morphology (biology)|morphological]] and [[Anatomy|anatomical]] similarities.<ref>{{cite web |title=Nested Hierarchies, the Order of Nature: Carolus Linnaeus |work=Understanding Evolution: The History of Evolutionary Thought |publisher=The University of California at Berkeley |url= https://evolution.berkeley.edu/evolibrary/article/0_0_0/history_05 |access-date=August 2, 2019 |archive-date=August 2, 2019 |archive-url= https://web.archive.org/web/20190802105432/https://evolution.berkeley.edu/evolibrary/article/0_0_0/history_05 |url-status=live}}</ref>

=== Darwin ===
The possibility of linking humans with earlier apes by descent became clear only after 1859 with the publication of [[Charles Darwin]]'s ''[[On the Origin of Species]]'', in which he argued for the idea of the evolution of new species from earlier ones. Darwin's book did not address the question of human evolution, saying only that "Light will be thrown on the origin of man and his history."{{sfn|Darwin|1859|pp=[http://darwin-online.org.uk/content/frameset?itemID=F373&viewtype=text&pageseq=506 367–404]}}

The first debates about the nature of human evolution arose between [[Thomas Henry Huxley]] and [[Richard Owen]]. Huxley argued for human evolution from apes by illustrating many of the similarities and differences between humans and other apes, and did so particularly in his 1863 book ''[[Evidence as to Man's Place in Nature]]''. Many of Darwin's early supporters (such as [[Alfred Russel Wallace]] and [[Charles Lyell]]) did not initially agree that the origin of the mental capacities and the moral sensibilities of humans could be explained by [[natural selection]], though this later changed. Darwin applied the theory of evolution and [[sexual selection]] to humans in his 1871 book ''[[The Descent of Man, and Selection in Relation to Sex]]''.{{sfn|Darwin|1981}}

=== First fossils ===
A major problem in the 19th century was the lack of [[Transitional fossil|fossil intermediaries]]. [[Neanderthal]] remains were discovered in a limestone quarry in 1856, three years before the publication of ''On the Origin of Species'', and Neanderthal fossils had been discovered in Gibraltar even earlier, but it was originally claimed that these were the remains of a modern human who had suffered some kind of illness.{{sfn|Montgomery|1988|pp=95–96}} Despite the 1891 discovery by [[Eugène Dubois]] of what is now called ''Homo erectus'' at [[Trinil]], [[Java]], it was only in the 1920s when such fossils were discovered in Africa, that intermediate species began to accumulate.<ref>{{Cite journal |last1=Shipman |first1=Pat |last2=Storm |first2=Paul |date=2002 |title=Missing links: Eugène Dubois and the origins of paleoanthropology |journal=Evolutionary Anthropology: Issues, News, and Reviews |volume=11 |issue=3 |pages=108–116 |doi=10.1002/evan.10021 |s2cid=84889438 |issn=1520-6505}}</ref> In 1925, [[Raymond Dart]] described ''[[Australopithecus africanus]]''.<ref>{{cite journal |last=Dart |first=Raymond |author-link=Raymond Dart |date=February 7, 1925 |title=''Australopithecus africanus'': The Man-Ape of South Africa |journal=[[Nature (journal)|Nature]] |volume=115 |issue=2884 |pages=195–199 |doi=10.1038/115195a0 |issn=0028-0836 |bibcode=1925Natur.115..195D |s2cid=4142569 |doi-access=free}}</ref> The [[Type (biology)|type specimen]] was the [[Taung Child]], an australopithecine infant which was discovered in a cave. The child's remains were a remarkably well-preserved tiny skull and an [[endocast]] of the brain.

Although the brain was small (410&nbsp;cm<sup>3</sup>), its shape was rounded, unlike that of chimpanzees and gorillas, and more like a modern human brain. Also, the specimen showed short [[Canine tooth|canine teeth]], and the position of the [[foramen magnum]] (the hole in the skull where the spine enters) was evidence of [[bipedal]] locomotion. All of these traits convinced Dart that the Taung Child was a bipedal human ancestor, a transitional form between apes and humans.

=== The East African fossils ===
[[File:Fossil hominids.jpg|thumb|upright|left|[[Fossil]] [[hominid]] evolution display at [[The Museum of Osteology]], [[Oklahoma City]], Oklahoma, US]]

During the 1960s and 1970s, hundreds of fossils were found in East Africa in the regions of the [[Olduvai Gorge]] and [[Lake Turkana]]. These searches were carried out by the Leakey family, with [[Louis Leakey]] and his wife [[Mary Leakey]], and later their son [[Richard Leakey|Richard]] and daughter-in-law [[Meave Leakey|Meave]], fossil hunters and paleoanthropologists. From the fossil beds of Olduvai and Lake Turkana they amassed specimens of the early hominins: the australopithecines and ''Homo'' species, and even ''H.&nbsp;erectus''.

These finds cemented Africa as the cradle of humankind. In the late 1970s and the 1980s, [[Ethiopia]] emerged as the new hot spot of paleoanthropology after [[Lucy (Australopithecus)|"Lucy"]], the most complete fossil member of the species ''[[Australopithecus afarensis]]'', was found in 1974 by [[Donald Johanson]] near [[Hadar, Ethiopia|Hadar]] in the desertic [[Afar Triangle]] region of northern Ethiopia. Although the specimen had a small brain, the pelvis and leg bones were almost identical in function to those of modern humans, showing with certainty that these hominins had walked erect.{{sfn|Johanson|Edey|1981|pp=20–22, 184–185}} Lucy was classified as a new species, ''Australopithecus afarensis'', which is thought to be more closely related to the genus ''Homo'' as a direct ancestor, or as a close relative of an unknown ancestor, than any other known hominid or hominin from this early time range.<ref>{{cite book |title=The Human Lineage |last1=Cartmill |first1=Matt |last2=Smith |first2=Fred H. |last3=Brown |first3=Kaye B. |page=[https://books.google.com/books?id=5TRHOmTUTP4C&pg=PA151 151] |date=2009 |publisher=Wiley-Blackwell |isbn=978-0-471-21491-5}}</ref> (The specimen was nicknamed "Lucy" after [[the Beatles]]' song "[[Lucy in the Sky with Diamonds]]", which was played loudly and repeatedly in the camp during the excavations.){{sfn|Johanson|Edey|1981|p=22}} The [[Afar Triangle]] area would later yield discovery of many more hominin fossils, particularly those uncovered or described by teams headed by [[Tim D. White]] in the 1990s, including ''[[Ardipithecus ramidus]]'' and ''[[Ardipithecus kadabba|A.&nbsp;kadabba]]''.<ref>{{cite journal |last=Shreeve |first=Jamie |date=July 2010 |title=The Evolutionary Road |url= http://ngm.nationalgeographic.com/2010/07/middle-awash/shreeve-text |journal=National Geographic |issn=0027-9358 |access-date=May 28, 2015 |archive-date=January 26, 2016 |archive-url= https://web.archive.org/web/20160126024510/http://ngm.nationalgeographic.com/2010/07/middle-awash/shreeve-text |url-status=dead}}</ref>

In 2013, fossil skeletons of ''[[Homo naledi]]'', an [[extinct species]] of [[hominin]] assigned (provisionally) to the genus ''Homo'', were found in the [[Rising Star Cave]] system, a site in South Africa's [[Cradle of Humankind]] region in [[Gauteng]] province near [[Johannesburg]].<ref>{{cite journal |doi=10.7554/eLife.09560 |volume=4 |title=''Homo naledi'', a new species of the genus ''Homo'' from the Dinaledi Chamber, South Africa |journal=eLife |pmid=26354291 |pmc=4559886 |date=September 10, 2015 |last1=Berger |first1=L. R. |last2=Hawks |first2=J. |last3=de Ruiter |first3=D. J. |last4=Churchill |first4=S. E. |display-authors=etal |doi-access=free}}{{collapsible list |title=Full list of authors |bullets=true |Lee R Berger |John Hawks |Darryl J de Ruiter |Steven E Churchill |Peter Schmid |Lucas K Delezene |Tracy L Kivell |Heather M Garvin |Scott A Williams |Jeremy M DeSilva |Matthew M Skinner |Charles M Musiba |Noel Cameron |Trenton W Holliday |William Harcourt-Smith |Rebecca R Ackermann |Markus Bastir |Barry Bogin |Debra Bolter |Juliet Brophy |Zachary D Cofran |Kimberly A Congdon |Andrew S Deane |Mana Dembo |Michelle Drapeau |Marina C Elliott |Elen M Feuerriegel |Daniel Garcia-Martinez |David J Green |Alia Gurtov |Joel D Irish |Ashley Kruger |Myra F Laird |Damiano Marchi |Marc R Meyer |Shahed Nalla |Enquye W Negash |Caley M Orr |Davorka Radovcic |Lauren Schroeder |Jill E Scott |Zachary Throckmorton |Matthew W Tocheri |Caroline VanSickle |Christopher S Walker |Pianpian Wei |Bernhard Zipfel}}</ref><ref name="NGS-20150910" /> {{As of|2015|9}}, fossils of at least fifteen individuals, amounting to 1,550 specimens, have been excavated from the cave.<ref name="NGS-20150910">{{cite web |last=Shreeve |first=Jamie |title=This Face Changes the Human Story. But How? |url= http://news.nationalgeographic.com/2015/09/150910-human-evolution-change/ |date=September 10, 2015 |work=[[National Geographic News]] |access-date=September 10, 2015 |archive-date=April 14, 2018 |archive-url= https://web.archive.org/web/20180414054102/https://news.nationalgeographic.com/2015/09/150910-human-evolution-change/ |url-status=dead}}</ref> The species is characterized by a body mass and stature similar to small-bodied human populations, a smaller [[Endocranium|endocranial]] volume similar to ''[[Australopithecus]]'', and a [[Skull|cranial]] [[Morphology (biology)|morphology]] (skull shape) similar to early ''Homo'' species. The skeletal anatomy combines primitive features known from [[australopithecine]]s with features known from early hominins. The individuals show signs of having been deliberately disposed of within the cave near the time of death. The fossils were dated close to 250,000 years ago,<ref>{{harvp|Dirks|Roberts|Hilbert-Wolf|Kramers|2017}}: between 335 and 236 ka. The lower limit of 236 ka is due to optically stimulated luminescence dating of sediments with U-Th and palaeomagnetic analyses of flowstones; the upper limit of 335 ka is due to U-series and electron spin resonance (US-ESR) dating of two ''H. naledi'' teeth, to {{val|253|82|70|u=ka}}, for an estimated age of the fossils of {{val|253|82|17|u=ka}}.</ref> and thus are not ancestral but contemporary with the first appearance of larger-brained [[anatomically modern humans]].<ref name="eLIFE-2017a">{{Cite journal |last1=Dirks |first1=Paul H. G. M. |first2=Eric M. |last2=Roberts |first3=Hannah |last3=Hilbert-Wolf |first4=Jan D. |last4=Kramers |first5=John |last5=Hawks |first6=Anthony |last6=Dosseto |first7=Mathieu |last7=Duval |first8=Marina |last8=Elliott |first9=Mary |last9=Evans |first10=Rainer |last10=Grün |first11=John |last11=Hellstrom |first12=Andy I. R. |last12=Herries |first13=Renaud |last13=Joannes-Boyau |first14=Tebogo V. |last14=Makhubela |first15=Christa J. |last15=Placzek |first16=Jessie |last16=Robbins |first17=Carl |last17=Spandler |first18=Jelle |last18=Wiersma |first19=Jon |last19=Woodhead |first20=Lee R. |last20=Berger |display-authors=4 |name-list-style=vanc |date=May 9, 2017 |title=The age of ''Homo naledi'' and associated sediments in the Rising Star Cave, South Africa |journal=eLife |volume=6 |pages=e24231 |pmid=28483040 |pmc=5423772 |doi=10.7554/eLife.24231 |doi-access=free}}{{collapsible list| title=Full list of authors| bullets=true| Paul H.G.M. Dirks| Eric M. Roberts| Hannah Hilbert-Wolf| Jan D. Kramers| John Hawks| Anthony Dosseto| Mathieu Duval| Marina Elliott| Mary Evans| Rainer Grün| John Hellstrom| Andy I.R. Herries| Renaud Joannes-Boyau| Tebogo V. Makhubela| Christa J. Placzek| Jessie Robbins| Carl Spandler| Jelle Wiersma| Jon Woodhead| Lee R. Berger}}</ref>

=== The genetic revolution ===

The genetic revolution in studies of human evolution started when [[Vincent Sarich]] and [[Allan Wilson (biologist)|Allan Wilson]] measured the strength of immunological cross-reactions of [[Serum (blood)|blood serum]] [[albumin]] between pairs of creatures, including humans and African apes (chimpanzees and gorillas).<ref name="MolClock">{{Cite journal |last1=Sarich |first1=V. M. |last2=Wilson |first2=A. C. |title=Immunological time scale for hominid evolution |journal=[[Science (journal)|Science]] |volume=158 |issue=3805 |pages=1200–1204 |date=1967 |pmid=4964406 |doi=10.1126/science.158.3805.1200 |bibcode=1967Sci...158.1200S |s2cid=7349579}}</ref> The strength of the reaction could be expressed numerically as an immunological distance, which was in turn proportional to the number of [[amino acid]] differences between homologous proteins in different species. By constructing a calibration curve of the ID of species' pairs with known divergence times in the fossil record, the data could be used as a [[molecular clock]] to estimate the times of divergence of pairs with poorer or unknown fossil records.

In their seminal 1967 paper in ''[[Science (journal)|Science]]'', Sarich and Wilson estimated the divergence time of humans and apes as four to five million years ago,<ref name="MolClock" /> at a time when standard interpretations of the fossil record gave this divergence as at least 10 to as much as 30&nbsp;million years. Subsequent fossil discoveries, notably "Lucy", and reinterpretation of older fossil materials, notably ''[[Sivapithecus|Ramapithecus]]'', showed the younger estimates to be correct and validated the albumin method.

Progress in [[DNA sequencing]], specifically [[mitochondrial DNA]] (mtDNA) and then [[Human Y-chromosome DNA haplogroup|Y-chromosome DNA]] (Y-DNA) advanced the understanding of human origins.{{sfn|DeSalle|Tattersall|2008|p=[https://books.google.com/books?id=Bf4Sitw7YaIC&pg=PA146 146]}}{{sfn|M'charek|2005|p=[https://books.google.com/books?id=n-K436zeUY8C&pg=PA96 96]}}{{sfn|Trent|2005|p=[https://books.google.com/books?id=772BEp8ZyMYC&pg=PA6 6]}} Application of the [[molecular clock]] principle revolutionized the study of [[molecular evolution]].

On the basis of a separation from the [[orangutan]] between 10 and 20&nbsp;million years ago, earlier studies of the molecular clock suggested that there were about 76 mutations per generation that were not inherited by human children from their parents; this evidence supported the divergence time between hominins and chimpanzees noted above. However, a 2012 study in Iceland of 78 children and their parents suggests a mutation rate of only 36 mutations per generation; this datum extends the separation between humans and chimpanzees to an earlier period greater than 7&nbsp;million years ago ([[Year#SI prefix multipliers|Ma]]). Additional research with 226 offspring of wild chimpanzee populations in eight locations suggests that chimpanzees reproduce at age 26.5 years on average; which suggests the human divergence from chimpanzees occurred between 7 and 13&nbsp;mya. And these data suggest that ''Ardipithecus'' (4.5 Ma), ''Orrorin'' (6 Ma) and ''Sahelanthropus'' (7 Ma) all may be on the hominid [[Lineage (evolution)|lineage]], and even that the separation may have occurred outside the [[East African Rift]] region.

Furthermore, analysis of the two species' genes in 2006 provides evidence that after human ancestors had started to diverge from chimpanzees, interspecies mating between "proto-human" and "proto-chimpanzees" nonetheless occurred regularly enough to change certain genes in the new [[gene pool]]:
: A new comparison of the human and chimpanzee genomes suggests that after the two lineages separated, they may have begun interbreeding... A principal finding is that the [[X chromosome]]s of humans and chimpanzees appear to have [[Genetic divergence|diverged]] about 1.2&nbsp;million years more recently than the other chromosomes.
The research suggests:
: There were in fact two splits between the human and chimpanzee lineages, with the first being followed by interbreeding between the two populations and then a second split. The suggestion of a hybridization has startled paleoanthropologists, who nonetheless are treating the new genetic data seriously.<ref>{{cite news |last=Wade |first=Nicholas |author-link=Nicholas Wade |date=May 18, 2006 |title=Two Splits Between Human and Chimp Lines Suggested |url= https://www.nytimes.com/2006/05/18/science/18evolve.html |newspaper=The New York Times |access-date=April 20, 2015 |archive-date=May 18, 2022 |archive-url= https://web.archive.org/web/20220518095858/https://www.nytimes.com/2006/05/18/science/18evolve.html |url-status=live}}</ref>

=== The quest for the earliest hominin ===
In the 1990s, several teams of paleoanthropologists were working throughout Africa looking for evidence of the earliest divergence of the hominin lineage from the great apes. In 1994, Meave Leakey discovered ''[[Australopithecus anamensis]]''. The find was overshadowed by Tim D. White's 1995 discovery of ''Ardipithecus ramidus'', which pushed back the fossil record to {{ma|4.2}}.

In 2000, [[Martin Pickford]] and [[Brigitte Senut]] discovered, in the [[Tugen Hills]] of [[Kenya]], a 6-million-year-old bipedal hominin which they named ''[[Orrorin|Orrorin tugenensis]]''. And in 2001, a team led by [[Michel Brunet (paleontologist)|Michel Brunet]] discovered the skull of ''[[Sahelanthropus|Sahelanthropus tchadensis]]'' which was dated as {{ma|7.2|million years ago}}, and which Brunet argued was a bipedal, and therefore a hominid—that is, a hominin ({{lang|la|{{abbr|cf|confer}}}} [[Hominidae]]; terms "hominids" and hominins).

=== Human dispersal ===
{{See also|Early human migrations|Recent African origin of modern humans|Multiregional origin of modern humans|Archaic humans in Southeast Asia}}
{{multiple image
| total_width       = 570
| footer            = Different models for the beginning of the present human species
| image1            = World map of prehistoric human migrations.jpg
| alt1              = Map with arrows emanating from Africa, across Eurasia, to Australia and the Americas.
| caption1          = A global mapping model of human migration, based from divergence of the [[mitochondrial DNA]] (which indicates the [[Lineage (genetic)|matrilineage]]).<ref name="Behar 2008" /><ref name="Gonder 2007" /><ref name="Tishkoff 2009" /> Timescale ([[Year#SI prefix multipliers|ka]]) indicated by colours.
| image2            = Homo trellis.jpg
| alt2              = Trellis of intermingling populations for the last two million years.
| caption2          = A "trellis" (as [[Milford H. Wolpoff]] called it) that emphasizes back-and-forth gene flow among geographic regions<ref>{{cite journal |last=Templeton |first=Alan R. |author-link=Alan Templeton |date=2005 |title=Haplotype Trees and Modern Human Origins |journal=[[American Journal of Physical Anthropology]] |volume=128 |issue=Supplement 41: Yearbook of Physical Anthropology |pages=33–59 |doi=10.1002/ajpa.20351 |issn=0002-9483 |pmid=16369961}}</ref>
}}

Anthropologists in the 1980s were divided regarding some details of reproductive barriers and migratory dispersals of the genus ''Homo''. Subsequently, genetics has been used to investigate and resolve these issues. According to the [[Sahara pump theory]] evidence suggests that the genus ''Homo'' have migrated out of Africa at least three and possibly four times (e.g. ''Homo erectus'', ''Homo heidelbergensis'' and two or three times for ''Homo sapiens''). Recent evidence suggests these dispersals are closely related to fluctuating periods of climate change.<ref>{{cite magazine |last=deMenocal |first=Peter B. |date=2016 |title=Climate Shocks |magazine=[[Scientific American]] |volume=25 |issue=4}}</ref>

Recent evidence suggests that humans may have left Africa half a million years earlier than previously thought. A joint Franco-Indian team has found human artifacts in the Siwalk Hills north of New Delhi dating back at least 2.6&nbsp;million years. This is earlier than the previous earliest finding of genus ''Homo'' at [[Dmanisi]], in [[Georgia (country)|Georgia]], dating to 1.85&nbsp;million years. Although controversial, tools found at a Chinese cave strengthen the case that humans used tools as far back as 2.48&nbsp;million years ago.<ref>{{cite magazine |last=Barras |first=Colin |title=Stone tools hint humans reached Asia much earlier |magazine=[[New Scientist]] |date=February 6, 2016}}</ref> This suggests that the Asian "Chopper" tool tradition, found in Java and northern China may have left Africa before the appearance of the [[Acheulian]] hand axe.

==== Dispersal of modern ''Homo sapiens'' ====
Up until the genetic evidence became available, there were two dominant models for the dispersal of modern humans. The [[Multiregional evolution|multiregional hypothesis]] proposed that the genus ''Homo'' contained only a single interconnected population as it does today (not separate species), and that its evolution took place worldwide continuously over the last couple of million years. This model was proposed in 1988 by [[Milford H. Wolpoff]].<ref>{{cite journal |last1=Wolpoff |first1=Milford H. |author1-link=Milford H. Wolpoff |last2=Hawks |first2=John |author2-link=John D. Hawks |last3=Caspari |first3=Rachel |date=May 2000 |title=Multiregional, Not Multiple Origins |journal=American Journal of Physical Anthropology |volume=112 |issue=1 |pages=129–136 |doi=10.1002/(SICI)1096-8644(200005)112:1<129::AID-AJPA11>3.0.CO;2-K |issn=0002-9483 |pmid=10766948 |url= http://www-personal.umich.edu/~wolpoff/Papers/Multiregional.PDF |hdl=2027.42/34270 |hdl-access=free |access-date=May 12, 2013 |archive-date=January 25, 2021 |archive-url= https://web.archive.org/web/20210125052356/http://www-personal.umich.edu/~wolpoff/Papers/Multiregional.PDF |url-status=live}}</ref><ref>{{cite journal |last1=Wolpoff |first1=M. H. |author1-link=Milford H. Wolpoff |last2=Spuhler |first2=J. N. |last3=Smith |first3=F. H. |last4=Radovcic |first4=J. |last5=Pope |first5=G. |last6=Frayer |first6=D. W. |last7=Eckhardt |first7=R. |last8=Clark |first8=G. |date=August 12, 1988 |title=Modern Human Origins |journal=[[Science (journal)|Science]] |volume=241 |issue=4867 |pages=772–774 |bibcode=1988Sci...241..772W |doi=10.1126/science.3136545 |issn=0036-8075 |pmid=3136545 |s2cid=5223638}}</ref> In contrast, the "out of Africa" model proposed that modern ''H.&nbsp;sapiens'' speciated in Africa recently (that is, approximately 200,000 years ago) and the subsequent migration through [[Eurasia]] resulted in the nearly complete replacement of other ''Homo'' species. This model has been developed by [[Chris Stringer]] and Peter Andrews.<ref>{{cite news |last=Owen |first=James |date=July 18, 2007 |url= http://news.nationalgeographic.com/news/2007/07/070718-african-origin.html |title=Modern Humans Came Out of Africa, 'Definitive' Study Says |work=National Geographic News |location=Washington, DC |publisher=[[National Geographic Society]] |access-date=May 14, 2011 |archive-date=June 27, 2018 |archive-url= https://web.archive.org/web/20180627005155/https://news.nationalgeographic.com/news/2007/07/070718-african-origin.html |url-status=dead}}</ref><ref>{{cite journal |last1=Stringer |first1=Chris B. |last2=Andrews |first2=Peter |date=March 11, 1988 |title=Genetic and fossil evidence for the origin of modern humans |journal=[[Science (journal)|Science]] |volume=239 |issue=4845 |pages=1263–1268 |issn=0036-8075 |bibcode=1988Sci...239.1263S |doi=10.1126/science.3125610 |pmid=3125610 |s2cid=39200956}}</ref>

Sequencing mtDNA and Y-DNA sampled from a wide range of indigenous populations revealed ancestral information relating to both male and female genetic heritage, and strengthened the "out of Africa" theory and weakened the views of multiregional evolutionism.{{sfn|Webster|2010|p=[https://books.google.com/books?id=cdiy1EhJVW0C&pg=PA53 53]}} Aligned in genetic tree differences were interpreted as supportive of a recent single origin.{{sfn|Ramachandran|Tang|Gutenkunst|Bustamante|2010|p=[https://books.google.com/books?id=FlfPSpBvKLgC&pg=PA606 606]}}

"Out of Africa" has thus gained much support from research using female mitochondrial DNA and the male [[Y chromosome]]. After analysing genealogy trees constructed using 133 types of mtDNA, researchers concluded that all were descended from a female African progenitor, dubbed [[Mitochondrial Eve]]. "Out of Africa" is also supported by the fact that mitochondrial genetic diversity is highest among African populations.<ref name="Cann">{{cite journal |last1=Cann |first1=Rebecca L. |author1-link=Rebecca L. Cann |last2=Stoneking |first2=Mark |author2-link=Mark Stoneking |last3=Wilson |first3=Allan C. |author3-link=Allan Wilson (biologist) |date=January 1, 1987 |title=Mitochondrial DNA and human evolution |url= http://artsci.wustl.edu/~landc/html/cann/ |journal=[[Nature (journal)|Nature]] |volume=325 |issue=6099 |pages=31–36 |bibcode=1987Natur.325...31C |doi=10.1038/325031a0 |issn=0028-0836 |pmid=3025745 |s2cid=4285418 |archive-url= https://web.archive.org/web/20100813121953/http://artsci.wustl.edu/~landc/html/cann/ |archive-date=August 13, 2010 |access-date=April 21, 2015}}</ref>

A broad study of African genetic diversity, headed by [[Sarah Tishkoff]], found the [[San people]] had the greatest genetic diversity among the 113 distinct populations sampled, making them one of 14 "ancestral population clusters". The research also located a possible origin of modern human migration in southwestern Africa, near the coastal border of [[Namibia]] and [[Angola]].<ref>{{cite news |last=Gill |first=Victoria |date=May 1, 2009 |title=Africa's genetic secrets unlocked |work=[[BBC News]] |location=London |publisher=BBC |url= http://news.bbc.co.uk/2/hi/science/nature/8027269.stm |access-date=June 8, 2011 |archive-date=May 14, 2020 |archive-url= https://web.archive.org/web/20200514095952/http://news.bbc.co.uk/2/hi/science/nature/8027269.stm |url-status=live}}</ref> The fossil evidence was insufficient for archaeologist [[Richard Leakey]] to resolve the debate about exactly where in Africa modern humans first appeared.{{sfn|Leakey|1994|pp=87–89}} Studies of [[haplogroup]]s in [[Human Y-chromosome DNA haplogroup|Y-chromosomal DNA]] and [[Human mitochondrial DNA haplogroup|mitochondrial DNA]] have largely supported a recent African origin.<ref>{{cite journal |last1=Jorde |first1=Lynn B. |last2=Bamshad |first2=Michael |last3=Rogers |first3=Alan R. |author3-link=Alan R. Rogers |date=February 1998 |title=Using mitochondrial and nuclear DNA markers to reconstruct human evolution |journal=BioEssays |volume=20 |issue=2 |pages=126–136 |doi=10.1002/(SICI)1521-1878(199802)20:2<126::AID-BIES5>3.0.CO;2-R |issn=0265-9247 |pmid=9631658 |s2cid=17203268}}</ref> All the evidence from autosomal DNA also predominantly supports a Recent African origin. However, evidence for [[Archaic human admixture with modern humans|archaic admixture in modern humans]], both in Africa and later, throughout Eurasia has recently been suggested by a number of studies.<ref>{{cite journal |last1=Wall |first1=Jeffrey D. |last2=Lohmueller |first2=Kirk E. |last3=Plagnol |first3=Vincent |date=August 2009 |title=Detecting Ancient Admixture and Estimating Demographic Parameters in Multiple Human Populations |pmid=19420049 |journal=Molecular Biology and Evolution |volume=26 |issue=8 |pages=1823–1827 |issn=0737-4038 |doi=10.1093/molbev/msp096 |pmc=2734152}}</ref>

Recent sequencing of Neanderthal<ref name="greenetal">{{cite journal |last1=Green |first1=R. E. |last2=Krause |first2=J. |last3=Briggs |first3=A. W. |last4=Maricic |first4=T. |last5=Stenzel |first5=U. |last6=Kircher |first6=M. |last7=Patterson |first7=N. |last8=Li |first8=H. |last9=Zhai |first9=W. |last10=Fritz |first10=M. H. Y. |last11=Hansen |first11=N. F. |last12=Durand |first12=E. Y. |last13=Malaspinas |first13=A. S. |last14=Jensen |first14=J. D. |last15=Marques-Bonet |first15=T. |last16=Alkan |first16=C. |last17=Prufer |first17=K. |last18=Meyer |first18=M. |last19=Burbano |first19=H. A. |last20=Good |first20=J. M. |last21=Schultz |first21=R. |last22=Aximu-Petri |first22=A. |last23=Butthof |first23=A. |last24=Höber |first24=B. |last25=Höffner |first25=B. |last26=Siegemund |first26=M. |last27=Weihmann |first27=A. |last28=Nusbaum |first28=C. |last29=Lander |first29=E. 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C. |last51=Slatkin |first51=M. |last52=Nielsen |first52=R. |last53=Kelso |first53=J. |last54=Lachmann |first54=M. |last55=Reich |first55=D. |last56=Pääbo |first56=S. |display-authors=4 |date=May 7, 2010 |title=A Draft Sequence of the Neandertal Genome |journal=[[Science (journal)|Science]] |volume=328 |issue=5979 |pages=710–722 |bibcode=2010Sci...328..710G |doi=10.1126/science.1188021 |issn=0036-8075 |pmid=20448178 |pmc=5100745}}{{collapsible list |title=Full list of authors |bullets=true |Richard E. Green |Johannes Krause |Adrian W. Briggs |Tomislav Maricic |Udo Stenzel |Martin Kircher |Nick Patterson |Heng Li |Weiwei Zhai |Markus Hsi-Yang Fritz |Nancy F. Hansen |Eric Y. Durand |Anna-Sapfo Malaspinas |Jeffrey D. Jensen |Tomas Marques-Bonet |Can Alkan |Kay Prüfer |Matthias Meyer |Hernán A. Burbano |Jeffrey M. Good |Rigo Schultz |Ayinuer Aximu-Petri |Anne Butthof |Barbara Höber |Barbara Höffner |Madlen Siegemund |Antje Weihmann |Chad Nusbaum |Eric S. Lander |Carsten Russ |Nathaniel Novod |Jason Affourtit |Michael Egholm |Christine Verna |Pavao Rudan |Dejana Brajkovic |Željko Kucan |Ivan Gušic |Vladimir B. Doronichev |Liubov V. Golovanova |Carles Lalueza-Fox |Marco de la Rasilla |Javier Fortea |Antonio Rosas |Ralf W. Schmitz |Philip L. F. Johnson |Evan E. Eichler |Daniel Falush |Ewan Birney |James C. Mullikin |Montgomery Slatkin |Rasmus Nielsen |Janet Kelso |Michael Lachmann |David Reich |[[Svante Pääbo]]}}</ref> and Denisovan<ref name="pmid21179161" /> genomes shows that some admixture with these populations has occurred. All modern human groups outside Africa have 1–4% or (according to more recent research) about 1.5–2.6% Neanderthal [[allele]]s in their genome,<ref name="A high-coverage Neandertal genome f">{{cite journal |last1=Prüfer |first1=K. |last2=de Filippo |first2=C. |last3=Grote |first3=S. |last4=Mafessoni |first4=F. |last5=Korlević |first5=P. |last6=Hajdinjak |first6=M. |title=A high-coverage Neandertal genome from Vindija Cave in Croatia |journal=[[Science (journal)|Science]] |date=2017 |doi=10.1126/science.aao1887 |pmid=28982794 |pmc=6185897 |display-authors=etal |volume=358 |issue=6363 |pages=655–658 |bibcode=2017Sci...358..655P}}</ref> and some [[Melanesians]] have an additional 4–6% of Denisovan alleles. These new results do not contradict the "out of Africa" model, except in its strictest interpretation, although they make the situation more complex. After recovery from a [[genetic bottleneck]] that some researchers speculate might be linked to the [[Toba catastrophe theory|Toba supervolcano catastrophe]], a fairly small group left Africa and interbred with Neanderthals, probably in the Middle East, on the Eurasian steppe or even in North Africa before their departure. Their still predominantly African descendants spread to populate the world. A fraction in turn interbred with Denisovans, probably in southeastern Asia, before populating Melanesia.<ref name="Reich_2011">{{cite journal |last1=Reich |first1=David |last2=Patterson |first2=Nick |last3=Kircher |first3=Martin |last4=Delfin |first4=Frederick |last5=Nandineni |first5=Madhusudan R. |last6=Pugach |first6=Irina |last7=Ko |first7=Albert Min-Shan |last8=Ko |first8=Ying-Chin |last9=Jinam |first9=Timothy A. |last10=Phipps |first10=Maude E. |last11=Saitou |first11=Naruya |last12=Wollstein |first12=Andreas |last13=Kayser |first13=Manfred |last14=Pääbo |first14=Svante |last15=Stoneking |first15=Mark |display-authors=3 |date=October 7, 2011 |title=Denisova Admixture and the First Modern Human Dispersals into Southeast Asia and Oceania |journal=American Journal of Human Genetics |volume=89 |issue=4 |pages=516–528 |doi=10.1016/j.ajhg.2011.09.005 |issn=0002-9297 |pmc=3188841 |pmid=21944045}}</ref> [[Human leukocyte antigen|HLA]] haplotypes of Neanderthal and Denisova origin have been identified in modern Eurasian and Oceanian populations.<ref name="10.1126/science.1209202" /> The Denisovan [[EPAS1]] gene has also been found in Tibetan populations.<ref>Huertha Sanchez, Emilia et al. (2014), "Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA" (Nature Vol 512, August 14, 2014)</ref> Studies of the human genome using machine learning have identified additional genetic contributions in Eurasians from an "unknown" ancestral population potentially related to the Neanderthal-Denisovan lineage.<ref>{{Cite web |url= https://www.sciencedaily.com/releases/2019/01/190116122650.htm |title=Artificial intelligence applied to the genome identifies an unknown human ancestor |website=[[ScienceDaily]] |access-date=January 17, 2019 |archive-date=January 16, 2019 |archive-url= https://web.archive.org/web/20190116213803/https://www.sciencedaily.com/releases/2019/01/190116122650.htm |url-status=live}}</ref>

[[File:Spreading homo sapiens la.svg|thumb|upright=1.5| A map of [[early human migrations]]]]

There are still differing theories on whether there was a single exodus from Africa or several. A multiple dispersal model involves the Southern Dispersal theory,<ref name="lahr">{{cite web |url= http://www.human-evol.cam.ac.uk/Projects/sdispersal/sdispersal.htm |title=Searching for traces of the Southern Dispersal |last1=Lahr |first1=Marta Mirazón |author1-link=Marta Mirazón Lahr |last2=Petraglia |first2=Mike |last3=Stokes |first3=Stephen |last4=Duller |first4=Geoff |display-authors=3 |website=Leverhulme Centre for Human Evolutionary Studies |publisher=[[University of Cambridge]] |archive-url= https://web.archive.org/web/20120510133600/http://www.human-evol.cam.ac.uk/Projects/sdispersal/sdispersal.htm |archive-date=May 10, 2012 |access-date=April 21, 2015}}</ref><ref>Simpson, Colin. [https://www.thenational.ae/uae/science/dna-evidence-suggests-the-whole-world-is-a-little-bit-arab-1.408619 DNA evidence suggests the whole world is a little bit Arab]. [[The National (Abu Dhabi)|The National]]. 16, June 2020. Archived at [https://web.archive.org/web/20200129100200/https://www.thenational.ae/uae/science/dna-evidence-suggests-the-whole-world-is-a-little-bit-arab-1.408619 The Wayback Machine]</ref><ref>{{cite journal |last1=Fernandes |first1=V. |last2=Alshamali |first2=F. |last3=Alves |first3=M. |display-authors=etal |title=The Arabian cradle: Mitochondrial relicts of the first steps along the southern route out of Africa |journal=[[American Journal of Human Genetics]] |date=2012 |volume=90 |issue=2 |pages=347–355 |doi=10.1016/j.ajhg.2011.12.010 |pmid=22284828 |pmc=3276663 }}</ref> which has gained support in recent years from genetic, linguistic and archaeological evidence. In this theory, there was a coastal dispersal of modern humans from the [[Horn of Africa]] crossing the Bab el Mandib to Yemen at a lower sea level around 70,000 years ago. This group helped to populate Southeast Asia and Oceania, explaining the discovery of early human sites in these areas much earlier than those in the [[Levant]].<ref name="lahr" /> This group seems to have been dependent upon marine resources for their survival.

[[Stephen Oppenheimer]] has proposed a second wave of humans may have later dispersed through the Persian Gulf oases, and the Zagros mountains into the Middle East. Alternatively it may have come across the [[Sinai Peninsula]] into Asia, from shortly after 50,000 yrs BP, resulting in the bulk of the human populations of Eurasia. It has been suggested that this second group possibly possessed a more sophisticated "big game hunting" tool technology and was less dependent on coastal food sources than the original group. Much of the evidence for the first group's expansion would have been destroyed by the rising sea levels at the end of each [[glacial maximum]].<ref name="lahr" /> The multiple dispersal model is contradicted by studies indicating that the populations of Eurasia and the populations of Southeast Asia and Oceania are all descended from the same mitochondrial DNA L3 [[Lineage (genetic)|lineages]], which support a single migration out of Africa that gave rise to all non-African populations.<ref>{{cite journal |last1=Macaulay |first1=Vincent |last2=Hill |first2=Catherine |last3=Achilli |first3=Alessandro |last4=Rengo |first4=Chiara |last5=Clarke |first5=D. |last6=Meehan |first6=W. |last7=Blackburn |first7=J. |last8=Semino |first8=O. |last9=Scozzari |first9=R. |last10=Cruciani |first10=F. |last11=Taha |first11=A. |last12=Shaari |first12=N. K. |last13=Raja |first13=J. M. |last14=Ismail |first14=P. |last15=Zainuddin |first15=Z. |last16=Goodwin |first16=W. |last17=Bulbeck |first17=D. |last18=Bandelt |first18=H. J. |last19=Oppenheimer |first19=S. |last20=Torroni |first20=A. |last21=Richards |first21=M. |display-authors=3 |date=May 13, 2005 |title=Single, Rapid Coastal Settlement of Asia Revealed by Analysis of Complete Mitochondrial Genomes |journal=[[Science (journal)|Science]] |volume=308 |issue=5724 |pages=1034–1036 |bibcode=2005Sci...308.1034M |doi=10.1126/science.1109792 |issn=0036-8075 |pmid=15890885 |s2cid=31243109 |url= http://psasir.upm.edu.my/id/eprint/40255/1/Single%2C%20rapid%20coastal%20settlement%20of%20Asia%20revealed%20by%20analysis%20of%20complete%20mitochondrial%20genomes.pdf |url-status=live |access-date=August 20, 2019 |archive-url= https://web.archive.org/web/20220828110206/http://psasir.upm.edu.my/id/eprint/40255/1/Single%2C%20rapid%20coastal%20settlement%20of%20Asia%20revealed%20by%20analysis%20of%20complete%20mitochondrial%20genomes.pdf |archive-date=August 28, 2022}}</ref>

On the basis of the early date of Badoshan Iranian Aurignacian, Oppenheimer suggests that this second dispersal may have occurred with a pluvial period about 50,000 years before the present, with modern human big-game hunting cultures spreading up the Zagros Mountains, carrying modern human genomes from Oman, throughout the Persian Gulf, northward into Armenia and Anatolia, with a variant travelling south into Israel and to Cyrenicia.<ref name="oppenheimer">{{cite book |last=Oppenheimer |first=Stephen |date=2012 |title=Out of Eden: The Peopling of the World |publisher=Robinson |edition=New}}</ref>

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