In paleoanthropology, the recent African origin of modern humans or the "Out of Africa" theory (OOA) [a] is the most widely accepted [1] [2] [3] model of the geographic origin and early migration of anatomically modern humans ( Homo sapiens ). It follows the early expansions of hominins out of Africa, accomplished by Homo erectus and then Homo neanderthalensis .
The model proposes a "single origin" of Homo sapiens in the taxonomic sense, precluding parallel evolution in other regions of traits considered anatomically modern, [4] but not precluding multiple admixture between H. sapiens and archaic humans in Europe and Asia. [b] [5] [6] H. sapiens most likely developed in the Horn of Africa between 300,000 and 200,000 years ago, [7] [8] although an alternative hypothesis argues that diverse morphological features of H. sapiens appeared locally in different parts of Africa and converged due to gene flow between different populations within the same period. [9] [10] The "recent African origin" model proposes that all modern non-African populations are substantially descended from populations of H. sapiens that left Africa after that time.
There were at least several "out-of-Africa" dispersals of modern humans, possibly beginning as early as 270,000 years ago, including 215,000 years ago to at least Greece, [11] [12] [13] and certainly via northern Africa and the Arabian Peninsula about 130,000 to 115,000 years ago. [20] There is evidence that modern humans had reached China around 80,000 years ago. [21] Practically all of these early waves seem to have gone extinct or retreated back, and present-day humans outside Africa descend mainly from a single expansion about 70,000–50,000 years ago, [22] [23] [24] [7] [8] [25] [26] [ excessive citations ] via the so-called "Southern Route". These humans spread rapidly along the coast of Asia and reached Australia by around 65,000–50,000 years ago, [27] [28] [c] (though some researchers question the earlier Australian dates and place the arrival of humans there at 50,000 years ago at earliest, [29] [30] while others have suggested that these first settlers of Australia may represent an older wave before the more significant out of Africa migration and thus not necessarily be ancestral to the region's later inhabitants [24] ) while Europe was populated by an early offshoot which settled the Near East and Europe less than 55,000 years ago. [31] [32] [33]
In the 2010s, studies in population genetics uncovered evidence of interbreeding that occurred between H. sapiens and archaic humans in Eurasia, Oceania and Africa, [34] [35] [36] indicating that modern population groups, while mostly derived from early H. sapiens, are to a lesser extent also descended from regional variants of archaic humans.
"Recent African origin", or Out of Africa II, refers to the migration of anatomically modern humans ( Homo sapiens ) out of Africa after their emergence at c. 300,000 to 200,000 years ago, in contrast to "Out of Africa I", which refers to the migration of archaic humans from Africa to Eurasia from before 1.8 and up to 0.5 million years ago. Omo-Kibish I (Omo I) from southern Ethiopia is the oldest anatomically modern Homo sapiens skeleton currently known (around 233,000 years old). [38] There are even older Homo sapiens fossils from Jebel Irhoud in Morocco which exhibit a mixture of modern and archaic features at around 315,000 years old. [39]
Since the beginning of the 21st century, the picture of "recent single-origin" migrations has become significantly more complex, due to the discovery of modern-archaic admixture and the increasing evidence that the "recent out-of-Africa" migration took place in waves over a long time. As of 2010, there were two main accepted dispersal routes for the out-of-Africa migration of early anatomically modern humans, the "Northern Route" (via Nile Valley and Sinai) and the "Southern Route" via the Bab-el-Mandeb strait. [40]
Beginning 135,000 years ago, tropical Africa experienced megadroughts which drove humans from the land and towards the sea shores, and forced them to cross over to other continents. [49] [e]
Fossils of early Homo sapiens were found in Qafzeh and Es-Skhul Caves in Israel and have been dated to 80,000 to 120,000 years ago. [50] [51] These humans seem to have either become extinct or retreated back to Africa 70,000 to 80,000 years ago, possibly replaced by southbound Neanderthals escaping the colder regions of ice-age Europe. [22] Hua Liu et al. analyzed autosomal microsatellite markers dating to about 56,000 years ago. They interpret the paleontological fossil as an isolated early offshoot that retracted back to Africa. [23]
The discovery of stone tools in the United Arab Emirates in 2011 at the Faya-1 site in Mleiha, Sharjah, indicated the presence of modern humans at least 125,000 years ago, [14] leading to a resurgence of the "long-neglected" North African route. [15] [52] [16] [17] This new understanding of the role of the Arabian dispersal began to change following results from archaeological and genetic studies stressing the importance of southern Arabia as a corridor for human expansions out of Africa. [53]
In Oman, a site was discovered by Bien Joven in 2011 containing more than 100 surface scatters of stone tools belonging to the late Nubian Complex, known previously only from archaeological excavations in the Sudan. Two optically stimulated luminescence age estimates placed the Arabian Nubian Complex at approximately 106,000 years old. This provides evidence for a distinct Stone Age technocomplex in southern Arabia, around the earlier part of the Marine Isotope Stage 5. [54]
According to Kuhlwilm and his co-authors, Neanderthals contributed genetically to modern humans then living outside of Africa around 100,000 years ago: humans which had already split off from other modern humans around 200,000 years ago, and this early wave of modern humans outside Africa also contributed genetically to the Altai Neanderthals. [55] They found that "the ancestors of Neanderthals from the Altai Mountains and early modern humans met and interbred, possibly in the Near East, many thousands of years earlier than previously thought". [55] According to co-author Ilan Gronau, "This actually complements archaeological evidence of the presence of early modern humans out of Africa around and before 100,000 years ago by providing the first genetic evidence of such populations." [55] Similar genetic admixture events have been noted in other regions as well. [56]
By some 50–70,000 years ago, a subset of the bearers of mitochondrial haplogroup L3 migrated from East Africa into the Near East. It has been estimated that from a population of 2,000 to 5,000 individuals in Africa, only a small group, possibly as few as 150 to 1,000 people, crossed the Red Sea. [57] [58] The group that crossed the Red Sea travelled along the coastal route around Arabia and the Persian Plateau to India, which appears to have been the first major settling point. [59] Wells (2003) argued for the route along the southern coastline of Asia, across about 250 kilometres (155 mi)[ dubious – discuss ], reaching Australia by around 50,000 years ago.
Today at the Bab-el-Mandeb straits, the Red Sea is about 20 kilometres (12 mi) wide, but 50,000 years ago sea levels were 70 m (230 ft) lower (owing to glaciation) and the water channel was much narrower. Though the straits were never completely closed, they were narrow enough to have enabled crossing using simple rafts, and there may have been islands in between. [40] [60] Shell middens 125,000 years old have been found in Eritrea, [61] indicating that the diet of early humans included seafood obtained by beachcombing.
The dating of the Southern Dispersal is a matter of dispute. [48] It may have happened either pre- or post-Toba, a catastrophic volcanic eruption that took place between 69,000 and 77,000 years ago at the site of present-day Lake Toba in Sumatra, Indonesia. Stone tools discovered below the layers of ash deposited in India may point to a pre-Toba dispersal but the source of the tools is disputed. [48] An indication for post-Toba is haplo-group L3, that originated before the dispersal of humans out of Africa and can be dated to 60,000–70,000 years ago, "suggesting that humanity left Africa a few thousand years after Toba". [48] Some research showing slower than expected genetic mutations in human DNA was published in 2012, indicating a revised dating for the migration to between 90,000 and 130,000 years ago. [62] Some more recent research suggests a migration out-of-Africa of around 50,000-65,000 years ago of the ancestors of modern non-African populations, similar to most previous estimates. [24] [63] [64]
Following the fossils dating 80,000 to 120,000 years ago from Qafzeh and Es-Skhul Caves in Israel there are no H. sapiens fossils in the Levant until the Manot 1 fossil from Manot Cave in Israel, dated to 54,700 years ago, [65] though the dating was questioned by Groucutt et al. (2015). The lack of fossils and stone tool industries that can be safely associated with modern humans in the Levant has been taken to suggest that modern humans were outcompeted by Neanderthals until around 55,000 years ago, who would have placed a barrier on modern human dispersal out of Africa through the Northern Route. [66] [ failed verification ] Climate reconstructions also support a Southern Route dispersal of modern humans as the Bab-el-Mandeb strait experienced a climate more conductive to human migration than the northern landbridge to the Levant during the major human dispersal out of Africa. [67]
A 2023 study proposed that Eurasians and Africans genetically diverged ~100,000 years ago. Main Eurasians then lived in the Saudi Peninsula, genetically isolated from at least 85 kya, before expanding north 54 kya. For reference, Homo sapiens and Neanderthals diverged ~500 kya. [68]
It is thought that Australia was inhabited around 65,000–50,000 years ago. As of 2017, the earliest evidence of humans in Australia is at least 65,000 years old, [27] [28] while McChesney stated that
...genetic evidence suggests that a small band with the marker M168 migrated out of Africa along the coasts of the Arabian Peninsula and India, through Indonesia, and reached Australia very early, between 60,000 and 50,000 years ago. This very early migration into Australia is also supported by Rasmussen et al. (2011). [31]
Fossils from Lake Mungo, Australia, have been dated to about 42,000 years ago. [69] [70] Other fossils from a site called Madjedbebe have been dated to at least 65,000 years ago, [71] [72] though some researchers doubt this early estimate and date the Madjedbebe fossils at about 50,000 years ago at the oldest. [29] [30]
Phylogenetic data suggests that an early Eastern Eurasian (Eastern non-African) meta-population trifurcated somewhere in eastern South Asia, and gave rise to the Australo-Papuans, the Ancient Ancestral South Indians (AASI), as well as East/Southeast Asians, although Papuans may have also received some gene flow from an earlier group (xOoA), around 2%, [73] next to additional archaic admixture in the Sahul region. [74] [75]
According to one study, Papuans could have either formed from a mixture between an East Eurasian lineage and lineage basal to West and East Asians, or as a sister lineage of East Asians with or without a minor basal OoA or xOoA contribution. [76]
A Holocene hunter-gatherer sample (Leang_Panninge) from South Sulawesi was found to be genetically in between East-Eurasians and Australo-Papuans. The sample could be modeled as ~50% Papuan-related and ~50% Basal-East Asian-related (Andamanese Onge or Tianyuan). The authors concluded that Basal-East Asian ancestry was far more widespread and the peopling of Insular Southeast Asia and Oceania was more complex than previously anticipated. [77] [78]
In China, the Liujiang man (Chinese :柳江人) is among the earliest modern humans found in East Asia. [79] The date most commonly attributed to the remains is 67,000 years ago. [80] High rates of variability yielded by various dating techniques carried out by different researchers place the most widely accepted range of dates with 67,000 BP as a minimum, but do not rule out dates as old as 159,000 BP. [80] Liu, Martinón-Torres et al. (2015) claim that modern human teeth have been found in China dating to at least 80,000 years ago. [81]
Tianyuan man from China has a probable date range between 38,000 and 42,000 years ago, while Liujiang man from the same region has a probable date range between 67,000 and 159,000 years ago. According to 2013 DNA tests, Tianyuan man is related "to many present-day Asians and Native Americans". [82] [83] [84] [85] [86] Tianyuan is similar in morphology to Liujiang man, and some Jōmon period modern humans found in Japan, as well as modern East and Southeast Asians. [87] [88] [89]
A 2021 study about the population history of Eastern Eurasia, concluded that distinctive Basal-East Asian (East-Eurasian) ancestry originated in Mainland Southeast Asia at ~50,000BC from a distinct southern Himalayan route, and expanded through multiple migration waves southwards and northwards respectively. [90]
Genetic studies concluded that Native Americans descended from a single founding population that initially split from a Basal-East Asian source population in Mainland Southeast Asia around 36,000 years ago, at the same time at which the proper Jōmon people split from Basal-East Asians, either together with Ancestral Native Americans or during a separate expansion wave. They also show that the basal northern and southern Native American branches, to which all other Indigenous peoples belong, diverged around 16,000 years ago. [91] [92] An indigenous American sample from 16,000BC in Idaho, which is craniometrically similar to modern Native Americans as well as Paleosiberias, was found to have largely East-Eurasian ancestry and showed high affinity with contemporary East Asians, as well as Jōmon period samples of Japan, confirming that Ancestral Native Americans split from an East-Eurasian source population in Eastern Siberia. [93]
According to Macaulay et al. (2005), an early offshoot from the southern dispersal with haplogroup N followed the Nile from East Africa, heading northwards and crossing into Asia through the Sinai. This group then branched, some moving into Europe and others heading east into Asia. [32] This hypothesis is supported by the relatively late date of the arrival of modern humans in Europe as well as by archaeological and DNA evidence. [32] Based on an analysis of 55 human mitochondrial genomes (mtDNAs) of hunter-gatherers, Posth et al. (2016) argue for a "rapid single dispersal of all non-Africans less than 55,000 years ago". By 45,000 years ago, modern humans are known to have reached northwestern Europe. [94]
The first lineage to branch off from Mitochondrial Eve was L0. This haplogroup is found in high proportions among the San of Southern Africa and the Sandawe of East Africa. It is also found among the Mbuti people. [95] [96] These groups branched off early in human history and have remained relatively genetically isolated since then. Haplogroups L1, L2, and L3 are descendants of L1–L6, and are largely confined to Africa. The macro haplogroups M and N, which are the lineages of the rest of the world outside Africa, descend from L3. L3 is about 70,000 years old, while haplogroups M and N are about 65–55,000 years old. [97] [64] The relationship between such gene trees and demographic history is still debated when applied to dispersals. [98]
Of all the lineages present in Africa, the female descendants of only one lineage, mtDNA haplogroup L3, are found outside Africa. If there had been several migrations, one would expect descendants of more than one lineage to be found. L3's female descendants, the M and N haplogroup lineages, are found in very low frequencies in Africa (although haplogroup M1 populations are very ancient and diversified in North and North-east Africa) and appear to be more recent arrivals.[ citation needed ] A possible explanation is that these mutations occurred in East Africa shortly before the exodus and became the dominant haplogroups thereafter by means of the founder effect. Alternatively, the mutations may have arisen shortly afterwards.
Results from mtDNA collected from aboriginal Malaysians called Orang Asli indicate that the haplogroups M and N share characteristics with original African groups from approximately 85,000 years ago, and share characteristics with sub-haplogroups found in coastal south-east Asian regions, such as Australasia, the Indian subcontinent and throughout continental Asia, which had dispersed and separated from their African progenitor approximately 65,000 years ago. This southern coastal dispersal would have occurred before the dispersal through the Levant approximately 45,000 years ago. [32] This hypothesis attempts to explain why haplogroup N is predominant in Europe and why haplogroup M is absent in Europe. Evidence of the coastal migration is thought to have been destroyed by the rise in sea levels during the Holocene epoch. [99] Alternatively, a small European founder population that had expressed haplogroup M and N at first, could have lost haplogroup M through random genetic drift resulting from a bottleneck (i.e. a founder effect).
The group that crossed the Red Sea travelled along the coastal route around Arabia and Persia until reaching India. [59] Haplogroup M is found in high frequencies along the southern coastal regions of Pakistan and India and it has the greatest diversity in India, indicating that it is here where the mutation may have occurred. [59] Sixty percent of the Indian population belong to Haplogroup M. The indigenous people of the Andaman Islands also belong to the M lineage. The Andamanese are thought to be offshoots of some of the earliest inhabitants in Asia because of their long isolation from the mainland. They are evidence of the coastal route of early settlers that extends from India to Thailand and Indonesia all the way to eastern New Guinea. Since M is found in high frequencies in highlanders from New Guinea and the Andamanese and New Guineans have dark skin and Afro-textured hair, some scientists think they are all part of the same wave of migrants who departed across the Red Sea ~60,000 years ago in the Great Coastal Migration. The proportion of haplogroup M increases eastwards from Arabia to India; in eastern India, M outnumbers N by a ratio of 3:1. Crossing into Southeast Asia, haplogroup N (mostly in the form of derivatives of its R subclade) reappears as the predominant lineage.[ citation needed ] M is predominant in East Asia, but amongst Indigenous Australians, N is the more common lineage.[ citation needed ] This haphazard distribution of Haplogroup N from Europe to Australia can be explained by founder effects and population bottlenecks. [100]
A 2002 study of African, European, and Asian populations, found greater genetic diversity among Africans than among Eurasians, and that genetic diversity among Eurasians is largely a subset of that among Africans, supporting the out of Africa model. [102] A large study by Coop et al. (2009) found evidence for natural selection in autosomal DNA outside of Africa. The study distinguishes non-African sweeps (notably KITLG variants associated with skin color), West-Eurasian sweeps (SLC24A5) and East-Asian sweeps (MC1R, relevant to skin color). Based on this evidence, the study concluded that human populations encountered novel selective pressures as they expanded out of Africa. [103] MC1R and its relation to skin color had already been discussed by Harding et al. (2000) , p. 1355. According to this study, Papua New Guineans continued to be exposed to selection for dark skin color so that, although these groups are distinct from Africans in other places, the allele for dark skin color shared by contemporary Africans, Andamanese and New Guineans is an archaism. Endicott et al. (2003) suggest convergent evolution. A 2014 study by Gurdasani et al. indicates that the higher genetic diversity in Africa was further increased in some regions by relatively recent Eurasian migrations affecting parts of Africa. [104]
Another promising route towards reconstructing human genetic genealogy is via the JC virus (JCV), a type of human polyomavirus which is carried by 70–90 percent of humans and which is usually transmitted vertically, from parents to offspring, suggesting codivergence with human populations. For this reason, JCV has been used as a genetic marker for human evolution and migration. [105] This method does not appear to be reliable for the migration out of Africa; in contrast to human genetics, JCV strains associated with African populations are not basal. From this Shackelton et al. (2006) conclude that either a basal African strain of JCV has become extinct or that the original infection with JCV post-dates the migration from Africa.
Evidence for archaic human species (descended from Homo heidelbergensis ) having interbred with modern humans outside of Africa, was discovered in the 2010s. This concerns primarily Neanderthal admixture in all modern populations except for Sub-Saharan Africans but evidence has also been presented for Denisova hominin admixture in Australasia (i.e. in Melanesians, Aboriginal Australians and some Negritos). [106] The rate of Neanderthal admixture to European and Asian populations as of 2017 has been estimated at between about 2–3%. [107]
Archaic admixture in some Sub-Saharan African populations hunter-gatherer groups (Biaka Pygmies and San), derived from archaic hominins that broke away from the modern human lineage around 700,000 years ago, was discovered in 2011. The rate of admixture was estimated at 2%. [36] Admixture from archaic hominins of still earlier divergence times, estimated at 1.2 to 1.3 million years ago, was found in Pygmies, Hadza and five Sandawe in 2012. [108] [35]
From an analysis of Mucin 7, a highly divergent haplotype that has an estimated coalescence time with other variants around 4.5 million years BP and is specific to African populations, it is inferred to have been derived from interbreeding between African modern and archaic humans. [109]
A study published in 2020 found that the Yoruba and Mende populations of West Africa derive between 2% and 19% of their genome from an as-yet unidentified archaic hominin population that likely diverged before the split of modern humans and the ancestors of Neanderthals and Denisovans. [110]
In addition to genetic analysis, Petraglia et al. also examines the small stone tools (microlithic materials) from the Indian subcontinent and explains the expansion of population based on the reconstruction of paleoenvironment. He proposed that the stone tools could be dated to 35 ka in South Asia, and the new technology might be influenced by environmental change and population pressure. [111]
The cladistic relationship of humans with the African apes was suggested by Charles Darwin after studying the behaviour of African apes, one of which was displayed at the London Zoo. [113] The anatomist Thomas Huxley had also supported the hypothesis and suggested that African apes have a close evolutionary relationship with humans. [114] These views were opposed by the German biologist Ernst Haeckel, who was a proponent of the Out of Asia theory. Haeckel argued that humans were more closely related to the primates of South-east Asia and rejected Darwin's African hypothesis. [115] [116]
In The Descent of Man , Darwin speculated that humans had descended from apes, which still had small brains but walked upright, freeing their hands for uses which favoured intelligence; he thought such apes were African:
In each great region of the world the living mammals are closely related to the extinct species of the same region. It is, therefore, probable that Africa was formerly inhabited by extinct apes closely allied to the gorilla and chimpanzee; and as these two species are now man's nearest allies, it is somewhat more probable that our early progenitors lived on the African continent than elsewhere. But it is useless to speculate on this subject, for an ape nearly as large as a man, namely the Dryopithecus of Lartet, which was closely allied to the anthropomorphous Hylobates, existed in Europe during the Upper Miocene period; and since so remote a period the earth has certainly undergone many great revolutions, and there has been ample time for migration on the largest scale.
— Charles Darwin, Descent of Man [117]
In 1871, there were hardly any human fossils of ancient hominins available. Almost fifty years later, Darwin's speculation was supported when anthropologists began finding fossils of ancient small-brained hominins in several areas of Africa (list of hominina fossils). The hypothesis of recent (as opposed to archaic) African origin developed in the 20th century. The "Recent African origin" of modern humans means "single origin" (monogenism) and has been used in various contexts as an antonym to polygenism. The debate in anthropology had swung in favour of monogenism by the mid-20th century. Isolated proponents of polygenism held forth in the mid-20th century, such as Carleton Coon, who thought as late as 1962 that H. sapiens arose five times from H. erectus in five places. [118]
The historical alternative to the recent origin model is the multiregional origin of modern humans, initially proposed by Milford Wolpoff in the 1980s. This view proposes that the derivation of anatomically modern human populations from H. erectus at the beginning of the Pleistocene 1.8 million years BP, has taken place within a continuous world population. The hypothesis necessarily rejects the assumption of an infertility barrier between ancient Eurasian and African populations of Homo. The hypothesis was controversially debated during the late 1980s and the 1990s. [119] The now-current terminology of "recent-origin" and "Out of Africa" became current in the context of this debate in the 1990s. [120] Originally seen as an antithetical alternative to the recent origin model, the multiregional hypothesis in its original "strong" form is obsolete, while its various modified weaker variants have become variants of a view of "recent origin" combined with archaic admixture. [121] Stringer (2014) distinguishes the original or "classic" Multiregional model as having existed from 1984 (its formulation) until 2003, to a "weak" post-2003 variant that has "shifted close to that of the Assimilation Model". [122] [123]
In the 1980s, Allan Wilson together with Rebecca L. Cann and Mark Stoneking worked on genetic dating of the matrilineal most recent common ancestor of modern human populations (dubbed "Mitochondrial Eve"). To identify informative genetic markers for tracking human evolutionary history, Wilson concentrated on mitochondrial DNA (mtDNA), which is maternally inherited. This DNA material mutates quickly, making it easy to plot changes over relatively short times. With his discovery that human mtDNA is genetically much less diverse than chimpanzee mtDNA, Wilson concluded that modern human populations had diverged recently from a single population while older human species such as Neanderthals and Homo erectus had become extinct. [124] With the advent of archaeogenetics in the 1990s, the dating of mitochondrial and Y-chromosomal haplogroups became possible with some confidence. By 1999, estimates ranged around 150,000 years for the mt-MRCA and 60,000 to 70,000 years for the migration out of Africa. [125]
From 2000 to 2003, there was controversy about the mitochondrial DNA of "Mungo Man 3" (LM3) and its possible bearing on the multiregional hypothesis. LM3 was found to have more than the expected number of sequence differences when compared to modern human DNA (CRS). [126] Comparison of the mitochondrial DNA with that of ancient and modern aborigines, led to the conclusion that Mungo Man fell outside the range of genetic variation seen in Aboriginal Australians and was used to support the multiregional origin hypothesis. A reanalysis of LM3 and other ancient specimens from the area published in 2016, showed it to be akin to modern Aboriginal Australian sequences, inconsistent with the results of the earlier study. [127]
The Y chromosome, which is paternally inherited, does not go through much recombination and thus stays largely the same after inheritance. Similar to Mitochondrial Eve, this could be studied to track the male most recent common ancestor ("Y-chromosomal Adam" or Y-MRCA). [128]
The most basal lineages have been detected in West, Northwest and Central Africa, suggesting plausibility for the Y-MRCA living in the general region of "Central-Northwest Africa". [16]
A Stanford University School of Medicine study was done by comparing Y-chromosome sequences and mtDNA in 69 men from different geographic regions and constructing a family tree. It was found that the Y-MRCA lived between 120,000 and 156,000, and the Mitochondrial Eve lived between 99,000 and 148,000 years ago, which not only predates some proposed waves of migration, but also meant that both lived in the African continent around the same time period. [129]
Another study finds a plausible placement in "the north-western quadrant of the African continent" for the emergence of the A1b haplogroup. [130] The 2013 report of haplogroup A00 found among the Mbo people of western present-day Cameroon is also compatible with this picture. [131]
The revision of Y-chromosomal phylogeny since 2011 has affected estimates for the likely geographical origin of Y-MRCA as well as estimates on time depth. By the same reasoning, future discovery of presently-unknown archaic haplogroups in living people would again lead to such revisions. In particular, the possible presence of between 1% and 4% Neanderthal-derived DNA in Eurasian genomes implies that the (unlikely) event of a discovery of a single living Eurasian male exhibiting a Neanderthal patrilineal line would immediately push back T-MRCA ("time to MRCA") to at least twice its current estimate. However, the discovery of a Neanderthal Y-chromosome by Mendez et al. was tempered by a 2016 study that suggests the extinction of Neanderthal patrilineages, as the lineage inferred from the Neanderthal sequence is outside of the range of contemporary human genetic variation. [132] Questions of geographical origin would become part of the debate on Neanderthal evolution from Homo erectus .
Human evolution is the evolutionary process within the history of primates that led to the emergence of Homo sapiens as a distinct species of the hominid family that includes all the great apes. This process involved the gradual development of traits such as human bipedalism, dexterity, and complex language, as well as interbreeding with other hominins, indicating that human evolution was not linear but weblike. The study of the origins of humans involves several scientific disciplines, including physical and evolutionary anthropology, paleontology, and genetics; the field is also known by the terms anthropogeny, anthropogenesis, and anthropogony.
Early modern human (EMH), or anatomically modern human (AMH), are terms used to distinguish Homo sapiens that are anatomically consistent with the range of phenotypes seen in contemporary humans, from extinct archaic human species. This distinction is useful especially for times and regions where anatomically modern and archaic humans co-existed, for example, in Paleolithic Europe. Among the oldest known remains of Homo sapiens are those found at the Omo-Kibish I archaeological site in south-western Ethiopia, dating to about 233,000 to 196,000 years ago, the Florisbad site in South Africa, dating to about 259,000 years ago, and the Jebel Irhoud site in Morocco, dated about 315,000 years ago.
In human genetics, the Y-chromosomal most recent common ancestor is the patrilineal most recent common ancestor (MRCA) from whom all currently living humans are descended. He is the most recent male from whom all living humans are descended through an unbroken line of their male ancestors. The term Y-MRCA reflects the fact that the Y chromosomes of all currently living human males are directly derived from the Y chromosome of this remote ancestor. The analogous concept of the matrilineal most recent common ancestor is known as "Mitochondrial Eve", the most recent woman from whom all living humans are descended matrilineally. As with "Mitochondrial Eve", the title of "Y-chromosomal Adam" is not permanently fixed to a single individual, but can advance over the course of human history as paternal lineages become extinct.
Homo is a genus of great ape that emerged from the genus Australopithecus and encompasses only a single extant species, Homo sapiens, along with a number of extinct species classified as either ancestral or closely related to modern humans; these include Homo erectus and Homo neanderthalensis. The oldest member of the genus is Homo habilis, with records of just over 2 million years ago. Homo, together with the genus Paranthropus, is probably most closely related to the species Australopithecus africanus within Australopithecus. The closest living relatives of Homo are of the genus Pan, with the ancestors of Pan and Homo estimated to have diverged around 5.7-11 million years ago during the Late Miocene.
Behavioral modernity is a suite of behavioral and cognitive traits believed to distinguish current Homo sapiens from other anatomically modern humans, hominins, and primates. Most scholars agree that modern human behavior can be characterized by abstract thinking, planning depth, symbolic behavior, music and dance, exploitation of large game, and blade technology, among others.
Neanderthals became extinct around 40,000 years ago. Hypotheses on the causes of the extinction include violence, transmission of diseases from modern humans which Neanderthals had no immunity to, competitive replacement, extinction by interbreeding with early modern human populations, natural catastrophes, climate change and inbreeding depression. It is likely that multiple factors caused the demise of an already low population.
Archaic humans is a broad category denoting all species of the genus Homo that are not Homo sapiens. Among the earliest modern human remains are those from Jebel Irhoud in Morocco, Florisbad in South Africa (259 ka), Omo-Kibish I in southern Ethiopia, and Apidima Cave in Southern Greece. Some examples of archaic humans include H. antecessor (1200–770 ka), H. bodoensis (1200–300 ka), H. heidelbergensis (600–200 ka), Neanderthals, H. rhodesiensis (300–125 ka) and Denisovans.
The Bacho Kiro cave is situated 5 km (3.1 mi) west of the town Dryanovo, Bulgaria, only 300 m (980 ft) away from the Dryanovo Monastery. It is embedded in the canyons of the Andaka and Dryanovo River. It was opened in 1890 and the first recreational visitors entered the cave in 1938, two years before it was renamed in honor of Bulgarian National Revival leader, teacher and revolutionary Bacho Kiro. The cave is a four-storey labyrinth of galleries and corridors with a total length of 3,600 m (11,800 ft), 700 m (2,300 ft) of which are maintained for public access and equipped with electrical lights since 1964. An underground river has over time carved out the many galleries that contain countless stalactone, stalactite, and stalagmite speleothem formations of great beauty. Galleries and caverns of a 1,200 m (3,900 ft) long section have been musingly named as a popular description of this fairy-tale underground world. The formations succession: Bacho Kiro’s Throne, The Dwarfs, The Sleeping Princess, The Throne Hall, The Reception Hall, The Haidouti Meeting-Ground, The Fountain and the Sacrificial Altar.
The genetic history of Europe includes information around the formation, ethnogenesis, and other DNA-specific information about populations indigenous, or living in Europe.
Early human migrations are the earliest migrations and expansions of archaic and modern humans across continents. They are believed to have begun approximately 2 million years ago with the early expansions out of Africa by Homo erectus. This initial migration was followed by other archaic humans including H. heidelbergensis, which lived around 500,000 years ago and was the likely ancestor of Denisovans and Neanderthals as well as modern humans. Early hominids had likely crossed land bridges that have now sunk.
In the context of the recent African origin of modern humans, the Southern Dispersal scenario refers to the early migration along the southern coast of Asia, from the Arabian Peninsula via Persia and India to Southeast Asia and Oceania. Alternative names include the "southern coastal route" or "rapid coastal settlement", with later descendants of those migrations eventually colonizing the rest of Eastern Eurasia, the remainder of Oceania, and the Americas.
Haplogroup H is a human mitochondrial DNA (mtDNA) haplogroup. The clade is believed to have originated in Southwest Asia, near present day Syria, around 20,000 to 25,000 years ago. Mitochondrial haplogroup H is today predominantly found in Europe, and is believed to have evolved before the Last Glacial Maximum (LGM). It first expanded in the northern Near East and Southern Caucasus, and later migrations from Iberia suggest that the clade reached Europe before the Last Glacial Maximum. The haplogroup has also spread to parts of Africa, Siberia and Inner Asia. Today, around 40% of all maternal lineages in Europe belong to haplogroup H.
In human mitochondrial genetics, L is the mitochondrial DNA macro-haplogroup that is at the root of the anatomically modern human mtDNA phylogenetic tree. As such, it represents the most ancestral mitochondrial lineage of all currently living modern humans, also dubbed "Mitochondrial Eve".
The multiregional hypothesis, multiregional evolution (MRE), or polycentric hypothesis, is a scientific model that provides an alternative explanation to the more widely accepted "Out of Africa" model of monogenesis for the pattern of human evolution.
The Denisovans or Denisova hominins are an extinct species or subspecies of archaic human that ranged across Asia during the Lower and Middle Paleolithic, and lived, based on current evidence, from 285 to 25 thousand years ago. Denisovans are known from few physical remains; consequently, most of what is known about them comes from DNA evidence. No formal species name has been established pending more complete fossil material.
Interbreeding between archaic and modern humans occurred during the Middle Paleolithic and early Upper Paleolithic. The interbreeding happened in several independent events that included Neanderthals and Denisovans, as well as several unidentified hominins.
Ust'-Ishim man is the term given to the 45,000-year-old remains of one of the early modern humans to inhabit western Siberia. The fossil is notable in that it had intact DNA which permitted the complete sequencing of its genome, one of the oldest modern human genomes to be so decoded.
Recent human evolution refers to evolutionary adaptation, sexual and natural selection, and genetic drift within Homo sapiens populations, since their separation and dispersal in the Middle Paleolithic about 50,000 years ago. Contrary to popular belief, not only are humans still evolving, their evolution since the dawn of agriculture is faster than ever before. It has been proposed that human culture acts as a selective force in human evolution and has accelerated it; however, this is disputed. With a sufficiently large data set and modern research methods, scientists can study the changes in the frequency of an allele occurring in a tiny subset of the population over a single lifetime, the shortest meaningful time scale in evolution. Comparing a given gene with that of other species enables geneticists to determine whether it is rapidly evolving in humans alone. For example, while human DNA is on average 98% identical to chimp DNA, the so-called Human Accelerated Region 1 (HAR1), involved in the development of the brain, is only 85% similar.
Basal Eurasian is a proposed lineage of anatomically modern humans with reduced, or zero, Neanderthal admixture (ancestry) compared to other ancient non-Africans. Basal Eurasians represent a sister lineage to other Eurasians and may have originated from the Southern Middle East, specifically the Arabian Peninsula, or North Africa, and are said to have contributed ancestry to various West Eurasian, South Asian, and Central Asian as well as African groups. This Basal Eurasian component is also proposed to explain the lower archaic admixture among modern West Eurasians compared with East Eurasians, although alternatives without the need of such Basal admixture exist as well. Basal Eurasian ancestry had likely admixed into West Eurasian groups present in West Asia as early as 26,000 years ago, prior to the Last Glacial Maximum, with this ancestry being subsequently spread by later migrations, such as those of the Anatolian Neolithic Farmers into Europe during the Holocene.
The genetic history of Africa summarizes the genetic makeup and population history of African populations in Africa, composed of the overall genetic history, including the regional genetic histories of North Africa, West Africa, East Africa, Central Africa, and Southern Africa, as well as the recent origin of modern humans in Africa. The Sahara served as a trans-regional passageway and place of dwelling for people in Africa during various humid phases and periods throughout the history of Africa.
The qpGraph analysis confirmed this branching pattern, with the Leang Panninge individual branching off from the Near Oceanian clade after the Denisovan gene flow, although with the most supported topology indicating around 50% of a basal East Asian component contributing to the Leang Panninge genome (Fig. 3c, Supplementary Figs. 7–11).
We interpret this temporal and technological affinity to signal a cultural connection with Upper Paleolithic northeastern Asia, which complements current evidence of shared genetic heritage between late Pleistocene peoples of northern Japan and North America.