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=== Summary   ===
'''Summary'''


Current evidence indicates that Homo sapiens evolved in Africa between roughly 300 000 and 200 000 years ago. Rather than arising in a single, isolated population, the species seems to have been shaped by interaction among several semi-independent populations spread across the continent, followed by expansions out of Africa and limited gene flow with Eurasian archaic groups such as Neanderthals and Denisovans [1] [2].
The best-supported view in 2025 is that Homo sapiens evolved within Africa from a metapopulation that was already geographically and genetically structured. Over hundreds of thousands of years these African lineages exchanged genes, producing the ancestral diversity shared by all living people today [1]. A subset of these Africans expanded into Eurasia roughly 60–70 kya, where additional, limited gene flow occurred with other hominins such as Neanderthals.  


=== Genetic and Fossil Evidence  ===
'''Key points from recent research'''


* Fossil remains at Jebel Irhoud (Morocco, ~300 ka) and Omo Kibish (Ethiopia, ~195 ka) display mixtures of modern and archaic traits, implying that “modern” morphology emerged gradually in different regions of Africa [1].
* Deep structure inside Africa. 
A new structured-coalescent model that fits whole-genome data from people on every inhabited continent shows that the ancestors of modern humans were subdivided for at least 1 million years before the most recent common ancestry of today’s populations [1]. Rather than a single “cradle,” the model supports several long-standing, semi-isolated populations linked by intermittent gene flow.


* Genome-wide analyses of present-day and ancient African DNA reveal deep population structure dating back >300 ka. These data are better explained by a network of populations exchanging migrants than by one isolated cradle [1].
* Out-of-Africa remains robust. 
Even with deep African structure, all non-African genomes still trace back to an expansion out of Africa within the last 100 kya [1]. This agrees with earlier genetic, palaeo-anthropological and archaeological evidence.


* Outside Africa, all living non-African humans share evidence of at least one expansion beginning ~70 ka, accompanied by introgression from Neanderthals (1–2 % of the genome) and, in some regions, Denisovans (up to 5 %) [2].
* Adaptive fine-tuning after the expansion. 
A 2024 ancient-DNA meta-analysis reports “pervasive directional selection” in traits tied to diet, immunity and climate adaptation after humans left Africa and settled new environments [3]. This indicates that the species’ origin predates (and is conceptually distinct from) later local adaptations.


=== Major Scientific Models  ===
'''Public discourse and open questions'''


Recent African Origin (RAO)  – Homo sapiens evolved in Africa and later replaced local Eurasian hominins except for limited admixture. This remains the core narrative for most geneticists [2].
Razib Khan describes the current picture as “complicated,” noting that the simple “single-origin, single-migration” story has been replaced by a model of “many Africas” and multiple pulses of expansion, contraction and introgression [2]. He emphasises that most researchers now see no contradiction between deep population structure inside Africa and the reality that all living humans are part of one species.


Pan-African Network  – Modern humans arose within a structured metapopulation that stretched across Africa; no single region exclusively holds the “origin” [1].
Palaeo-environmental studies highlighted in popular coverage of recent fieldwork underscore how climate shifts—such as the greening and drying of Arabian corridors—created windows that allowed small groups to leave Africa repeatedly [4]. Whether earlier forays left genetic traces, or were completely replaced by the later successful expansion, remains under debate.


Extended Multiregionalism within Africa  – A minority view emphasises near-continuous gene flow across Africa and Eurasia over the last million years. It has little direct genomic support and is not defended by either cited author. 
'''Points of agreement'''


=== Points of Consensus  ===
* All living humans share most of their ancestry with African Homo sapiens that existed ≥300 kya [1][2]. 
* A later expansion out of Africa populated the rest of the world and contributed the majority of ancestry outside the continent [1]. 
* Subsequent gene flow with archaic hominins was real but limited; it does not challenge the African origin of our species [2].


* Africa is the primary geographic source of anatomically modern humans [1] [2]. 
'''Points of contention'''


* All present-day non-Africans descend mainly from a late Pleistocene expansion out of Africa [2].   
* How many semi-independent populations made up the ancestral African metapopulation, and where they were located [1][2]. 
* Whether earlier “failed” dispersals left any surviving genetic legacy outside Africa [2][4].   
* The exact timing of the speciation process: some place the morphological roots of Homo sapiens >300 kya, while others propose a more recent genetic definition [1][2].


* Admixture with Neanderthals and Denisovans occurred after that expansion [2]. 
'''Consensus view'''


=== Points of Disagreement  ===
In sum, Homo sapiens is an African species that emerged from a long-lived, structured set of populations inside the continent. The single most successful out-of-Africa expansion about 60–70 kya spread those African genomes worldwide, after which local adaptations and limited archaic introgression shaped present-day diversity [1][3].
 
* How many ancestral populations within Africa contributed substantially to later humans? 
– Nature study argues for at least three long-standing lineages exchanging migrants [1]. 
– Razib Khan accepts deep structure but stresses that available data cannot yet resolve whether there were “three, six, or a dozen” such groups [2]. 
 
* Timing and rate of gene flow among those African lineages.
  – The Nature authors model continuous, low-level exchange [1]. 
  – Khan notes alternative models with pulses of admixture also fit current data [2]. 
 
=== Timeline of the Public Discourse  ===
 
1920s–1960s – Fossil discoveries feed the “single origin” (East Africa) vs. “multiregional” debate centred on morphology. 
 
1987 – Mitochondrial-DNA “Eve” paper popularises a recent African origin. 
 
1997–2010 – Ancient DNA confirms Neanderthals as a sister group; Neanderthal genome (2010) reveals admixture with modern humans, refining RAO rather than overthrowing it. 
 
2017 – Jebel Irhoud fossils extend modern-looking traits back to 300 ka, raising interest in a pan-African scenario. 
 
2020s – High-coverage genomes from understudied African populations and improved modelling lead to the metapopulation/pan-African synthesis promoted in the 2025 Nature study [1]. Blogs and podcasts (e.g., Razib Khan, 2024) stress the remaining “it’s complicated” aspects [2]. 
 
=== Remaining Open Questions  ===
 
* Which specific regions in Africa hosted the main ancestral lineages? 
 
* How did climatic oscillations regulate connectivity among African populations? 
 
* What is the precise contribution of yet-unsampled archaic African hominins? 
 
Ongoing fieldwork and ancient-DNA retrieval from tropical contexts are expected to clarify these issues over the next decade.


== Sources ==
== Sources ==
# https://www.nature.com/articles/s41588-025-02117-1
# [https://www.nature.com/articles/s41588-025-02117-1 A structured coalescent model reveals deep ancestral structure shared by all modern humans – ''Nature Genetics''] (2025 peer-reviewed research article)
# https://www.razibkhan.com/p/current-status-its-complicated
# [https://www.razibkhan.com/p/current-status-its-complicated Current Status: It’s Complicated – ''Razib Khan’s Unsupervised Learning''] (2023 newsletter essay / Blog commentary)
# [https://www.biorxiv.org/content/10.1101/2024.09.14.613021v1 Pervasive findings of directional selection realize the promise of ancient DNA to elucidate human adaptation – ''bioRxiv''] (2024 pre-print; Empirical research)
# https://phys.org/news/2023-10-path-early-human-migrations-once-lush.html


== Question ==
== Question ==
What is the origin of the human species?
What is the origin of the human species?
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