Duration of the Out Of Africa Migration, it was much slower than believed

Reading a paper about the peopling of Sundaland by Homo erectus (Husson et al., 2022, Javanese Homo erectus on the move in SE Asia circa 1.8 Ma, I learned something about the time it took these ancient hominins to people this southeastern part of Asia, and it was much longer than I expected.

The authors report that " H. erectus reached Java and dwelled at Sangiran, Java, ca. 1.8 Ma.... The dispersal of H. erectus across Sundaland occurred over at least tens to hundreds kyr."

Migration pathways of H. erectus across Sundaland during Early Pleistocene. (a) Reconstructed landscape ca. 1.8 Ma (model goSPL32). The underlying physiography, with overprinted modeled rivers, converts into a map of resistance to displacement that serves to compute the migration pathways, either using a least-cost path algorithm shown for the Myanmar entry point (purple), or a mechanistic movement model (SiMRiv30) exemplified for the Vietnam entry point (orange). Blue star locates the Thailand entry point.. Husson et al., 2022

The map above shows how different the landscape was around 1.8 million years ago, with an emerged area spanning not only the Indonesian islands but also a land bridge from Vietnam into Sundaland, separating the seas of China and Thailand. It also depicts in orange and purple, possible entry routes from the mainland Asian area to Sanigran in Indonesia.

The time spent walking

The point they studied is how long did the trek of these erectus people take. After all, there are remains in China and also in Georgia, at the Dmanisi site, around 1.9 to 2 million years old, and the Indonesian remains are just 100,000 years younger. Let's see what the authors say (my comments are underlined) and I highlight some relevant parts:

" How long did the journey take? While least-cost paths are 6,000 km long on average from mainland Asia to Java (Fig. 4a), the mean travelled distances are 50 times longer for Markovian walks (327 x 10³km), regardless of the north entry point, and almost always in excess of 100 x 10³ km. The corresponding time span depends on the migration speed. Estimates are available for more recent palaeolithic hominins, ranging from 1 to 10 km/yr [I will comment on this point further down]. At similar speeds, the least-cost paths convert into an optimal travel time of 0.6 to 6 kyr, which is thus the minimal time to cross Sundaland. Markovian walks imply much longer durations before hominins reached Java, between 25-40 kyr at fast moving rates, and 250-400 kyr at slow moving rates (Fig. 4b). These relatively long delays at average or slow moving rates are difficult to reconcile with the early arrival to Java ca. 1.8 Ma, following departure from Georgia or China only a few 100 kyr before. We suggest that because these characteristic travel times scale with the characteristic time scale of changes of the physical environment, external forcings impelled hominins to migrate and boosted their displacement.... We find that H. erectus migrated across Sundaland at remarkably fast rates (>10 km/yr) with respect to their prior journey across Eurasia, and to the displacement rates of other lineages of the genus Homo"

In other words, they estimate that the joureny could take between 25,000 and 400,000 years, to move from northern Thailand or Vietnam to Sanigran in Indonesia. And say that the erectus people walked faster than that because there were external forces pushing them forward (?).

They adopt a quicker pace to fit the timeline of not more than 100,000 years between the oldest Asian specimens in China and Georgia, and those found in Indonesia. So, the authors suggest a slow pace across Asia from Georgia to East Asia, and then a very quick entry into Indonesia.

The paper assumes a speed of 10 km per year for Homo erectus which is the speed at which the fastest "recent palaeolithic hominins" move at (see further up, where it places that speed at 1 to 10 km/y). In my opion, this is quick.

So, just taking straight lines as a course (this would assume the travelers knew in advance where they were going, which they didn't), the distance however from northern Thailand to Java is roughly 3,000 km (2,000 miles). Which they. Taking figure 4b in the paper, at 10 km per year this journey would have required between 7 and 62 ky, on average 32 ky. If these people would have moved at the slower limit found in more recent palaeolithic hominins, they would have required 320 ky to do so (70 to 620 ky).

Interestingly, the modern humans of the Out Of Africa wave are said to have trekked from the Sinai (starting 60 kya) to Beringia in only 40,000 years. That is a much longer distance (10,700 km - 6,700 mi) than the one into Sunda from northern Thailand. So, moving at the pace of the erectus that peopled Sunda, to cover this distance that is 3 times longer, it would have taken almost 100 ky on average. So if they set out 60 kya, they still haven't arrived in America! And walking at the lowere speed limit, it would have taken 1 million years.

Something is wrong in the dispersal speeds.

The paper seems to understand this implication, because it ends with an interesting conclusion: "At a more general scale, our TCN ages obtained for the first appearance datum of H. erectus in Sangiran advocate for an early peopling of Sundaland by H. erectus, contemporary with their Chinese and Georgian counterparts, whose endocranial capacity was much smaller than specimens from Sangiran. These results reignite the long-standing controversy over the origin and dispersal pathways of archaic humans and invites a reexamination of the out-of-Africa paradigm, which provides a global roadmap for the dispersal of the genus Homo, but which one-way direction may be questioned."

Directionality suggests Asia-To-Africa migrations, and the smaller-brain sizes of contemporary erectus in China and Georgia vs. Indonesia requires some explanation. Why would the more advanced erectus be those most distant from Africa, in Sangiran?

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 

An older date for the arrival of Modern Humans in SE Asia

We have all heard about the Out of Africa theory (OOA) that proposes an initial, failed, migration of humans into the Levant, from Africa around 150,000 years ago (150 ky) that died out and left no trace in our modern lineage. Then came the second, and final migration around 50 ky ago which peopled Eurasia, Oceania, and later, America. But, as we will see in this post, this timeline is not so certain.

A paper by Friedline et al., 2023 (Early presence of Homo sapiens in Southeast Asia by 86–68 kyr at Tam Pà Ling, Northern Laos) suggests that humans reached the southeastern side of Asia some 68,000 years ago.

The authors analyzed bone remains from Tam Pà Ling (TPL for short), and concluded that one of the specimens (known as TPL 6), "confirms the presence of H. sapiens by 70 ± 3 kyr, and TPL 7 extends this range to 77 ± 9 kyr, supporting an early dispersal of H. sapiens into Southeast Asia."

This adds evidence of en early presence of humans in the region. Another sites with old dates are the Sumatran one at Lida Ajer, which is around 73 ky old (Westway et al., 2017).

These dates are incompatible with the current OOA theory so how can these remains be fitted into it? The theory should be reevaluated and updated. Were these people survivors from the first "failed" migration? Did they evolve localy? Did they admix with Denisovans or archaics?

The article confirms that human beings lived at TPL for over 56,000 years! Several specimens were analyzed and they show affinities and differences with other humans from Asia.

Some highlighs regarding these people:

• "Geometric morphometric analyses of TPL 6 suggest descent from a gracile immigrant population rather than evolution from or admixture with local archaic populations."
• "The TPL fossils’ clear affinities to H. sapiens suggest that they descended from a gracile H. sapiens population from Africa, the Near East, or locally."
• "considerable shape and size variability is present at Tam Pà Ling... supporting previous observations that high levels of heterogeneity characterize Late Pleistocene modern human groups."
• "TPL 6 and potentially the younger fossils from Tam Pà Ling would represent an unsuccessful dispersal. Whether this dispersal disappeared prior to the main later dispersal or the distinct migrations experienced a period of co-habitation remains unclear with absence of ancient DNA from 50 to 10 kyr."

The analysis of the next oldest remains from the site, TPL, dated to 70 ky, shows that it has "affinities to Pleistocene archaic humans (e.g., non-H. sapiens Middle Pleistocene hominins and Neanderthals from Africa and Eurasia), plotting outside of the range of variation of early and Upper Paleolithic H. sapiens. This is mainly due to its large bi-mental breadth, an archaic feature also found in early H. sapiens and Neanderthals and associated with a wide ramus". An intriguing hint, in my opinion, of admixture with archaics in Euyrasia. The authors point out, however, that it had "a well-developed chin (mental osseum rank 537), a trademark of our species". They also compared TPL to the Chinese fossil Zhiren 3, which is around 100 ky old, and is more archaic, yet also has a prominent chin. The explanation for this feature is admixture of humans with archaics in Asia.

The authors point out the doubts surrounding the age of Zhiren, which could either be "an example of an early dispersal of H. sapiens that was unsuccessful. Alternatively, if the geological age is overestimated it could also be an example of one of the earliest inhabitants from a late dispersal."

Two other specimens, TPL1 and TPL2 are curious; they are 52-40 ky old, but have some oddities. TPL2 is small: 140–153 cm (less than 5 feet tall). TPL1, on the other hand has a roubust skull, with strong brow ridges, jutting lower jaw, which according to the authors "can be generally interpreted as a retention of ancestral morphology rather than admixture with local archaic populations". Why discard admixture with H. erectus or Denisovans? No explanation is given.

The paper concludes "TPL 6... provides direct evidence of an early, possibly unsuccessful, dispersal from Africa or the Near East towards Southeast Asia by 70 ± 3 kyr. TPL 6 is remarkably gracile implying that it descended from a gracile immigrant population and not the outcome of local evolution from, or admixture with, H. erectus or Denisovans. Our semilandmark geometric shape analyses of the other craniomandibular fossils from Tam Pà Ling (TPL 1, 2, and 3) are consistent with previous studies attributing them to H. sapiens, and their considerable shape and size variability suggests that high levels of heterogeneity characterize Late Pleistocene modern human groups."

The TPL6 is gracile, so they interpret it as lacking admixture with archaics. But, why did the other early specimens, TPL 1, 2 & 3, show such high variability, a mix of ancient, robust, and modern features? Doesn't this mosaic of old and modern features hint at admixture?

It seems likely that the first humans reached Southeast Asia much earlier than proposed by the current OOA theory. Their mosaic features hint at admixture with archaics in Asia. Possibly, humans could have originated outside of Africa after splitting from Neanderthal/Denisovans, and spread west into Africa, and east into the domains of the still extant Homo erectus.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 

A paper on skin pigmentation: San & Europeans share light skin alleles

I came across a recent paper published in Science in 2017 by Crawford et al., Loci associated with skin pigmentation identified in African populations, which holds some interesting facts about skin color genetics and when the dark and pale variants arose.

I have posted in the past about light skin pigmentation in Amerindians and Neanderthal skin color, but this post will look into light skin alleles shared by the San people of Africa and modern Europeans.

Skin color genes are ancient

When it comments on how skin pigmentation evolved in modern humans, the paper points out that there is a wide variability within Africa, from the most pale group (the San in southern Africa) to the East African people of the Nilo Saharian region, who aret the darkest. It correctly states that the genes causing both dark and light skin color evolved before our Homo sapiens species appeared around 300,000 years ago (300 ky).

Surprisingly, the paper finds that "the ancestral allele is associated with light pigmentation in about half of the predicted causal SNPs; Neandertal and Denisovan genome sequences, which diverged from modern human sequences 804 ka, contain the ancestral allele at all loci." So, our closest relatives in evolutionary terms carried this ancestral white-skinned allele with them. However, the paper tends to downplay this fact, and it says something which sounds the opposite: "These observations are consistent with the hypothesis that darker pigmentation is a derived trait that originated in the genus Homo within the past ~2 million years (My) after human ancestors lost most of their protective body hair" and then, like an afterthought mentions the paler tint of Neanderthals and Denisovans: "... although these ancestral hominins may have been moderately, rather than darkly, pigmented. Moreover, it appears that both light and dark pigmentation have continued to evolve over hominid history."

Shared genes between dark pigmented Africans and Australo-Melanesians

It mentions something I hadn't read before (I was always surprised by the similarity in the dark tint of pigmentation in Melanesians, Australian Aboriginal people, Andamenese islanders and Africans): they share a common genetic origin, and could be identical by descent (IBD). The paper says that "Individuals from South Asia and Australo-Melanesia share variants associated with dark pigmentation at MFSD12, DDB1/TMEM138, OCA2, and HERC2 that are identical by descent from Africans. This raises the possibility that other phenotypes shared between Africans and some South Asian and Australo-Melanesian populations may also be due to genetic variants identical by descent from African populations rather than convergent evolution."

It is indeed interesting to note that the bottleneck and founder effects and loss of diversity among the Out of Africa migration population managed to carry, intact, these alleles across Southern Asia, into Australia and Melanesia, while another group managed to carry the white, paler skin alleles.

A light pigmentation variant shared by San and Europeans

There is a variant at SNP rs1800404 within OCA2, that in its ancestral form (with a cytosine base or "C") is found in dark skinned East Asians, most Africans and Australians and Melanesians. The derived variant with a Thymine base or "T", is found in Europeans and the pruportedly most ancestral human beings, the San from southern Afirca! (found among these two groups in frequencies of over 70%). The split is ancient: " Coalescent analysis indicates that the TMRCA of all lineages is 1.7 Ma (95% CI, 1.5 to 2.0 Ma), and the TMRCA of lineages containing the derived (T) allele is 629 ka (95% CI, 426 to 848 ka)"

The tree shown above has two branches with the African one deeper (older) and shorter ones for most modern populations. Note the Oceanians and South Asians are on the African branch.

The allele shared by San and Europeans dates back approximately to the time Neanderthals and Denisovans split from the Modern human lineage.

Another region that acts upon skin color is HERC2, where SNP rs6497271 comes in an ancestral A variant (with an adenine base) providing dark pigmentation to Australo-Melanesians and Africans (identical in both groups, suggesting an identity by descent), and the derived base, (G) or guanine which is linked to lighter skin pigmentation and found in Europeans, and, yes, in the San people. This one is also old, dating back to "921 ka (95% CI, 703 ka to 1.2 Ma)".

If the dark "A" variant is IBD, the pale "G" one should also be IBD, and this one is possibly older than the Denisovan-Neanderthal / Human split as it is 921,000 years old.

The tree (above) show its distribution globally, with two branches the dark skin variant seems to have longer branches making it look more ancestral than the other, pale skin variants. I don't see the link between Africans and Australo-Melanesians in this tree, as mentioned by the authors.

How did Europeans and San people get to share this variant and the other OCA2 variant, while all the Africans living between both groups have the derived dark pigmentation variants? Note that there is 6,600 km (4,100 miles) between the southernmost tip of Europe in Greece and the San homeland in Botswana/Namibia.

We can imagine different alternatives to explain this: (1) A small population of modern humans split, one headed north into Europe, the other was displaced south into the southern tip of Africa. Between them, a mutation appeared, providing dark pigmentation for people living in the tropical regions of Africa, with benefits like UV protection, etc. (the paper hints that dark skin may have positive effects on other bodily functions: "...some of the pigmentation-associated variants identified here may be maintained because of pleiotropic effects on other aspects of human physiology."

Another option (2) is that pale pigmentation was prevalent among the archaic population that evolved into Neanderthal-Denisovan-Humans and moved with them across Eurasia but a later darker variant appeared in Africa and became predominant there, displacing the pale skin to the southern tip of Africa (San), and migrating out of Africa in a sub-population of modern humans that peopled South Asia and Australia-Melanesia (PNG, Aboriginals, Negrito, Andamanese people). Later overlaid by a wave of paler humans in Indonesia, Malaysia, Thailand and North India. Did the Europeans get pale skin from admixing with Neanderthals, and Asians from Denisovans?

(3) Prehaps ancient archaics had the darker pigmentation alleles, and a separate archaic group was lighter colored, the former remained in Africa (H. habilis), the latter moved into Eurasia (H. erectus?). Modern humans evolved in Asia, starting with Neanderthals and Denisovans, and back-migrated into Africa where admixture with archaics in Africa led to a darkening currently observed there. The san, part of the wave of migrants were displaced and isolated, retaining the original alleles. However, the dark skinned south Asians and Melanesians can't be accounted for with this model. Perhaps there was an Out of Africa migration along coastal South Asia into Melanesia? Or an ancient migration of superarchaics into Asia that mingled there with later populations?

In any case, I find it interesting that contemporary Europeans, who are deemed to be very recent, and the San people, supposedly the oldest intact group of humans, that split from the rest of us over 150,000 years ago, share the same light-skin pigmentation alleles. This oddity indicates that there is something amiss with our current idea of human origins and dispersal.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 
 

Diring Yuriakh site: Ancient humans in Siberia ~400 kya

The Diring Yuriakh site in Central Siberia shows that some humans reached the area long ago, well before modern humans had evolved in Africa, and more or less contemporary with the Denisovan and Neanderthal split. This was at least one hundred thousand years before Homo sapiens appeared.

But Siberia was a harsh environment, and the tools don't resemble Neanderthal Mousterian tool technology, it is more "primitive". Who were these humans braving the cold Siberian winters 400,000 years ago?

I found a very old (nearly 40 years old!) article in Science, Diring Yuriakh: A Lower Paleolithic Site in Central Siberia 🔒 by Forman, Pierson and Waters (1997) discussing the site and its archaic tools. (See it here too 🔓)

This paper mentions the accidental discovery of a site along the Lena River in Siberia, a spot known as Diring Yuriakh where stone tools were unearthed (see it in Google Maps). These were not natural (geofacts) stones, but man-made. The site was excavated by Mochanov, 1992 🔒, who believed they were very ancient, 1.8 to 3.2 million years old, which would place the makers of the tools found there in the Homo erectus or Homo habilis time period. Other researchers suggest a later date of 800,000 years (800 kya) to 1 million years, which would make them H. erectus or possibly the common ancestors of Denisovans and Neanderthals.

According to Richards, 1994, Y. A. Mochanov presented a paper in 1992 at the 45th Annual Northwest Anthropology Conference (The Earliest Palaeolithic of Northeastern Asia and the Problem of the Extratropical Cradle of Man) which gave thermoluminescence dating calculated by O.A. Kulikov of over 1.1 million years (My) for layer 6, 2.9 + 0.96 My for layer 5, and more than 1.8 My for layer 4. Richards recommends caution when considering those dates.

Unifacial choppers. From Fig. 3. in the article

The dates provided in the paper from 1997 (resulting from a 1993 samples obtained at the site), are a minimum of 260,000 years, and a maximum of around 370,000 years, on average, 300,000 years. Interestingly, Mochanov had previously reported other sites with similar artifacts in the same sedimentary layer, and hence, of the samey age, at 14 other sites along a 800 km (500 mi) section of the Lena River in Northeastern Siberia.

This site is very close to America, just 3,000 km west (1,880 miles) of Alaska.

How did these people survive in this bleak northern environment? The paper suggests that the people who lived here probably did so during a warm spell at the end of glacial period known as MIS 8 (Marine Isotope Stage 8) which spanned a period from 300 to 243 kya. Another option is the warmer interglacial stage 7 period (245-190 kya). But, even during the warmest summers, the climate would have been very cold, requiring the use of fire, warm clothing, and effective shelter strategies. This indicates that these people were well adapted to the harsh conditions of Siberia. How long they stayed here, or how much territory they coccupied is not known.

Simple Stone Tools

The image further up depicts some tools from this site, which look quite primitive. The paper reports finding over 4,000 artifacts, mostly cores and flakes. Around 500 of them are "unifacial pebble choppers core scrapers, and scraper planes. A few tools made from flakes are present in the assemblage."

Mochanov characterizes these tools as follows: "these tools more closely resemble those from Olduvai Gorge than from any other Early Pleistocene site, leading the author to ponder the possibility of a non-tropical origin for humanity." Indeed, the Olduvai tool industy is the most primitive one, and also the oldest. The Homo erectus later developed their Acheulean stone tool technology, an advance on the Oldowan one.

Now we know that the period suggested by the 1997 paper (260 to 370 kya) would have spanned the time that Denisovans were living in Eastern Asia together with Neanderthals on its western fringes. We don't have Denisovan toolkits for comparison, but the Mousterian tools of the Neanderthals were far more advanced than the Oldowan. This opens up the possibility that some well-adapted archaic hominin, probably even earlier than the erectus, or a group that opted for simple tools and not the Acheulean ones of the erectus, lived in the cold northern parts of eastern Siberia.

An archaeology blogger (NeilB, 1016) analyzed the data objectiely and concluded that "Verdict: Site inhabited ca. 300, 000 years ago. Likely candidates Homo erectus or Homo heidelbergensis.".

2024 Research places the age of Diring Yuriakh at 400 kya

More recently, a 2024 paper by John D. Jansen et al., (Redrawing early human dispersal patterns with cosmogenic nuclide, EGU24-4168, updated on 08 Mar 2024. https://doi.org/10.5194/egusphere-egu24-4168 EGU General Assembly 2024) used cosmogenic dating to date several Paleolithic sites in Europe, and also the Diring Yuriakh site, where they found "an age of 417 &plusm; 82 ka, which is at least 300 kyr earlier than the previously documented earliest human presence north of 60 degrees. This timing overlaps with exceptional warmth across the High North during the ‘super-interglacial’ MIS 11c (426–396 ka), suggesting that warm climate intervals permitted human migration well beyond widely accepted territorial bounds."

Janssen immediately understood the significance of such an old date in such a northerly location. He immediately suggested that these people could have moved on eastwards and reached America. But this will be the subject of a future post.

My next post will look into another site around 500 to 800 ky old, with cobble-styled stone tools close to the famous Denisova Cave, the Karama Site on Anui River, in the Altai, and then we will explore the subject of an early peopling of America by archaic humans from Siberia 400,000 or even more years ago.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 

Mosquitoes with a taste for human blood evolved first in Asia than in Africa, and did so 2.9 to 1.6 Ma

A research paper published in Nature on February 26, 2026, used some interesting genetic studies to support the idea that mosquitoes in Southeast Asia evolved a taste for human blood (anthropophily) at the time that the first hominins reached the area (Homo erectus). It is an interesting paper as it used data from the study of insects to confirm some ancient anthropological dates.

These are the details of this recent paper published in Nature on Feb. 26, 2026: Singh, U.S., Harbach, R.E., Hii, J. et al. Early hominin arrival in Southeast Asia triggered the evolution of major human malaria vectors. Sci Rep 16, 6973 (2026). https://doi.org/10.1038/s41598-026-35456-y

An ancient relationship: homo and mosquitoes. Source

In the abstract, it mentions that some species belonging to a group called Leucosphyrus, part of the Anopheles mosquitoes that live in Southeast Asia not only transmit malaria, they are also fine tuned to drinking human blood. Other mosquitoes in the region occupy different niches, feeding off other monkeys (non-human primates or NHP) and transmit NHP malaria variants. This study analyzed the genes of mosquitoes from 11 species (including their mtDNA) and built dated phylogenetic trees for them.

The paper found that the original, basal species of mosquitoes in this region were monkey-feeding ones, living in what is now Malaysia, Borneo, and the Indonesian islands of Java and Sumatra, when this area was linked by a now submerged continental shelf, into Sundaland. During that time (Pliocene) the area was covered by a lush rainforest. The authors believe that "anthropophily most likely evolved once, involving adaptive introgression, in the early Pleistocene in Sundaland, giving rise to multiple descendent anthropophilic species. Such early origination of anthropophily must necessarily have been in response to the arrival of early hominins (Homo erectus) rather than anatomically modern humans, likely associated with loss and fragmentation of rainforests during the early Pleistocene. The early origination of anthropophily also provides independent non-archaeological evidence supporting the limited fossil record of early hominin colonization in Southeast Asia around 1.8 Mya." This date is roughly when Homo erectus reached the area.

The article reveals that mosquitoes are host-specific and that many genes are involved in this specificity. So "multiple genetic changes at these and other genes are required for the evolution of anthropophily, i.e. a strong, evolved preference for human blood. It is not surprising therefore that anthropophily is uncommon amongst the ~ 3500 known mosquito species. It is therefore more parsimonious to consider that anthropophily within a taxon has a single origin. Accordingly, it is improbable that there were multiple independent switches to anthropophily in the human-preferring species of the Dirus and Balabacensis Clades, which diverged around 1.3–0.5 Mya. Even taking into account some uncertainty in the molecular clock used for these divergence estimates these clades far predate the arrival of anatomically modern humans in SE Asia 76,000–63,000 years ago. We therefore reject with confidence the hypothesis that anthropophily in the Leucosphyrus Subgroup evolved in response to the arrival of modern humans in SE Asia."

Therefore it was an ancient event, long before human beings appeared in Africa.

The article adds that "Using the same molecular clock rate as applied in this study and a species tree, anthropophily would be inferred to have evolved ~ 509,000–61,000 years ago in the lineage leading to the major African malaria vectors, An. gambiae and An. coluzzii... Since An. gambiae originates in West African forests the switch to anthropophilly may instead have occurred in response to modern humans entering this forested region ~ 150,000 years ago. The emergence of anthropophily in the domestic form of Aedes aegypti and the molestus ecotype of Culex pipiens, both date to within the last 10,000 years, apparently in response to growing human populations and environmental change." So, the African human-feeding mosquitoes took place independently, and later than the SE Asian event(

Finally, the article "indicates that anthropophily in the Leucosphyrus Subgroup emerged much earlier than in other anthropophilic mosquito species. If a strictly bifurcating tree were assumed, anthropophily could have evolved either: by the time of node N1 [95% CI: 2.9–1.8 Mya] and subsequently been lost in the lineage leading to An. nemophilous and An. introlatus; or evolved twice along the lineages leading to the Dirus Clade (N3, 1.6 Mya [95% CI: 2.0–1.2 Mya]) and the Balabacensis Clade (N5, 0.5 Mya [95% CI: 0.7–0.4 Mya]).... We therefore consider the most parsimonious argument for the evolution of anthropophily in the Leucosphyrus Subgroup to be that it evolved once only through the process of adaptive introgression at nodes N1/N2 as this accommodates the multiplicity of genes underlying the trait and negates any need to invoke loss of this trait. According to this hypothesis, anthropophily would have evolved between the extremes of the N1 and N2 confidence intervals i.e. between 2.9 and 1.6 mya (Fig. 3) when all the lineages were in Sundaland, and prior to the divergence of the Dirus Clade (node N3, 1.6 Mya [95% CI: 2.0–1.2 Mya]) further north in Indochina. This hypothesis could be tested against the above alternatives by identifying the genes underlying anthropophily and characterizing their evolutionary history."

The interesting part in the preceding text is that dates, which on the "older" tip of the scale reach 2.9 and 2 million years back. This is in line with the recent findings in Eurasia about an early Homo erectus dispersal across Asia.

The authors continue (highlight is mine): "Dating of the evolution of anthropophily in the Leucosphyrus Group to 2.9–1.6 mya overlaps with the earliest proposed date for the arrival of early hominins (Homo erectus) into Sundaland at 1.8 Mya, but not with the more recent proposed date of 1.3 Mya. Our findings suggest that anthropophily in the Leucosphyrus Group emerged in Sundaland in the early Pleistocene in response to the arrival of early hominins who must have not only been present in this region by this time but must have been in substantial numbers to drive adaptation to human host preference. This supports the hypothesis of Husson et al. that early hominins were present and abundant in Sundaland ~ 1.8 Mya, prior to their dispersal via land bridges to Java. Middle Pleistocene fossils of Homo erectus indicate their prolonged occupation on the exposed Sundaland landmass, likely associated with extensive river systems. In the context of the very fragmentary nature of the fossil record in tropical SE Asia our findings contribute an important piece of evidence to the broader puzzle of the colonization of hominins in insular Southeast Asia".

Closing Comments

These findings add up to the other evidence mentioned in recent posts, suggesting a very early out of Africa (or even an Eurasian origin of hominins!). I have tried to learn more about American mosquitoes that feed on humans, but research seems to be scarce in this area other than focusing on the main vectors of malaria, dengue, yellow fever, Zika, and chikungunya (see this 2022 paper as an example). If there are anthropophilic mosiquitoes in America that could be dated, what dates would they provide? (several strains reached America after the European discovery, from Africa and Eurasia, the Aedes aegypti vector of yellow fever and Zika) originated in Africa and arrived with the slave trade, and Aedes albopictus, the "Asian tiger mosquito" arrived 40 years ago, from Asia, in used tires! Would other local strains shed light on the date of the peopling of America?

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 

Homo erectus reached China 600 ky earlier than previously believed

Continuning with this series of posts on new findings in Asia, a paper published on February 18, 2026 (Hua Tu et al. (2026). The oldest in situ Homo erectus crania in eastern Asia: The Yunxian site dates to ~1.77 Ma. Sci. Adv. 12, eady2270. DOI:10.1126/sciadv.ady2270) reports that three skulls belonging to Homo erectus recovered from Yunxian, China were dated to an age of 1.77 million years. This is roughly 600,000 years older than previous estimates.

This new dating is very relevant because it shows a rapid expansion of these hominids across Asia: The oldest remains of erectus are found in Georgia (the Dmanisi site) and are 1.78 to 1.85 Ma. The remains from Indonesia are younger, for instance those from Sanigran are 1.5 to 1.66 Ma., and the age assigned to Chinese remains is close to 1.3 Ma.

Interestingly, this paper mentions two sites in China older than 2.1 million years: "Further, the earliest archaeological traces, as represented by Xihoudu [~2.4 Ma;] and Shangchen [~2.1 Ma]." This could imply a very early out of Africa migration of austraolpithecines perhaps! (see my post on erectus and australopiths in Dmanisi, Georgia).

Yunxian site is on the Han River, in Central China. The paper concludes that:

"The age for Yunxian also indicates that H. erectus at ~1.77 Ma was much more widespread than just Dmanisi in Georgia, although the latter site, at the top of the Olduvai subchron (1.78 to 1.85 Ma), should be slightly older. This supports a rapid dispersal model of H. erectus through Asia beginning after 2 Ma. As the dates for these hominin sites continue to be pushed back in time, it would suggest that the chronological gap between the earliest archaeology at sites like Xihoudu [~2.43 Ma] and Shangchen [~2.1 Ma] and hominin paleontology in China is quickly narrowing. Questions remain, however, as to when and where H. erectus initially appeared and could they have been among the earliest occupants at some of these sites in China and elsewhere that now date to the early Early Pleistocene. If not, then should we be considering alternative hominins as the possible earliest occupants of Asia, particularly because the earliest sites in Asia now predate the traditionally accepted appearance of Homo ergaster/H. erectus (~1.9 Ma). The dates for Yunxian presented here represent a step forward to addressing such questions."

An earlier presence of Homo or australopithecines in East Asia opens the door to a continued migration into America 1.7 to 2.1 million years ago.

The two older sites ~2 Ma

The two sites mentioned further up, over two million years old are linked to the following sources:

G. J. Shen, Y. R. Wang, H. Tu, H. W. Tong, Z. K. Wu, K. Kuman, D. Fink, D. E. Granger, Isochron 26Al/10Be burial dating of Xihoudu: Evidence for the earliest human settlement in northern China. Anthropologie 124, 102790 (2020).
Z. Zhu, R. Dennell, W. Huang, Y. Wu, S. Qiu, S. Yang, Z. Rao, Y. Hou, J. Xie, J. Han, T. Ouyang, Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago. Nature 559, 608–612 (2018).

I will look into them in a future post, and also, look int the possible origin of the homo group in Asia, instead of Africa.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 

Homo erectus left Africa earlier than thought (New 2026 paper)

As mentioned in yesterday's post, there have been some recent discoveries that are changing what we knew about the spread of our ancestors out of Africa and across Eurasia.

A new paper has disclosed that the site of Ubeidiya, in the Valley of the Jordan river has been dated to an age older than 1.9 million years. This is relevant because Acheulean tools, typical of Homo erectus have been found in those sediments, and this date is much older than previous estimates, pushing the first Out Of Africa event further back in time.

The paper: A. Matmon, et al., (2026). Complex exposure-burial history and Pleistocene sediment recycling in the dead sea rift with implications for the age of the Acheulean site of ‘Ubeidiya. Quaternary Science Reviews, Volume 378, 2026, 109871, ISSN 0277-3791, https://doi.org/10.1016/j.quascirev.2026.109871. 🔒

The Abstract reads as follows: "We present early Pleistocene burial ages of the ‘Ubeidiya Formation sediments in the Jordan Valley, a segment of the Dead Sea Rift Valley. A minimum age of ∼1.1 Ma is constrained both by paleomagnetic analysis and U-Pb dating of Melanopsis shells. Simple cosmogenic burial ages (i.e., one very long exposure period followed by one period of burial) calculated from the ratios of 26Al to 10Be and 10Be concentrations indicate ages of ∼3 Ma, contradicting the geological and paleomagnetic constraints as well as a reasonable age of the ‘Ubeidiya archeological site, as it contains human remains. A more sophisticated way of treating the results, by combining numerical modeling of cosmogenic nuclide build up during repeated burial-exposure cycles, paleomagnetic analysis (indicating reverse polarity) and a minimum burial age of 1.1 Ma set by U-Pb dating of Melanopsis shells, suggests two most probable time slots (1.19-1.77 and 1.93- 2.14 Ma) for the absolute age of the ‘Ubeidiya Formation. However, the skewed distribution of cosmogenic isotope burial ages, with a median age of 2.05 Ma, indicates a much higher probability of the older ages, most likely >1.9 Ma. The exposure-burial history that emerges from the model implies recycling of sediments previously deposited and buried in the rift valley, between 4.5 and 3.2 Ma, and subsequently exhumed, eroded, transported and then redeposited along the ‘Ubeidiya paleo lake shoreline."

Previous research had provided inconclusive dates, and used obscure methods. The consensus dates for the tools found there were between 1.2 and 1.6 million years. So this discovery pushes the first Out Of Africa migration back at least 300,000 years.

Furthermore, some previous dating of 3 Ma was due to the "recycling", that is the erosion of old strata, the transport and reburying of older sediment further down the valley making the sites seem older than they really are. However, the burial of sediments also preserved the information of magnetic field reversals which is a useful tool to date old strata ( magnetostratigraphy), the team also used radioactive decay of isotopes formed by cosmic rays in chert and quartz, and dating of snail shells using radioactive decay of Uranium to Lead. These three methods helped define the dating.

These dates make sense, because the earliest homo found in Eurasia, at Dmanisi, Georgia is slightly younger. This earlier presence of erectus in Israel, suggests that these erectus could have moved north towards Georgia, and also east, across Asia, reaching Eastern Asia (Indonesia and China) much earlier than previously expected (as we will see in my next post), and also, a possible continuation of their journey into America. They had almost 2 million years to do so before the arrival of Modern Humans in Eurasia.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 

China is redefining hominin evolution

A paywalled paper published three days ago (Feb. 24, 2026) in Nature (Yang, SX., Martinón-Torres, M. & Petraglia, M. Palaeoanthropological evidence from China is changing the picture of hominin evolutionary history. Nat Ecol Evol (2026). https://doi.org/10.1038/s41559-026-02983-w) reports on the recent research, datings and findings in China that have upended conventional beliefs about the evolution of our species.

"Abstract
Recent palaeoanthropological discoveries in China indicate that eastern Asia had an important role in the evolutionary history of the genus Homo over the past 2 million years. New taxonomic proposals have been made to re-group archaic human fossils, including those considered to be Denisovans, as Homo juluensis and Homo longi. The hypothesis that the affinities of Yunxian 2, dated to about 1 million years ago, also infer an early divergence of the Homo sapiens lineage further underscores China’s pivotal role in global evolutionary narratives. Here we explore key biological and cultural evidence emerging from the Chinese record and its evolutionary implications, raising questions about the relationships between ‘transitional’ clades and their differing adaptive capabilities. Rather than an evolutionary cul-de-sac, China now appears as a dynamic evolutionary crossroad where multiple Homo lineages may have arisen, interacted and adapted to shifting environments. The growing fossil and genetic evidence point to a diversity of populations whose demographic history and gene flow exchange helped to shape the broader mosaic of our species."

In my next two posts I will look into two very papers that report two remarkable findings: an earlier age for the first Out Of Africa event that saw Homo erectus enter Asia (or possibly, even an australopithecine) leave Africa 1.95 million years ago, and also a much older date for erectus' arrival in China. Plus two other papers mentioning sites that are possibly over 2 million years old in China.

I am not a Sinophile, and not because I dislike the Chinese people or their culture, quite the opposite. I have visited China many times before I retired as I worked for several years with companies there, visited customers, traveled the country extensively. I spent vacations there, with my wife, and I also have Chinese friends. I enjoy the food, the rich history, the diverse culture, and its natural sights. I am reluctant to embrace China because I am at odds with the system that governs that great nation. The Chinese Communist party, allied with the People's Liberation Army, is a one-party system that perpetuates a caste, an elite, living in luxury, backed by force that has, for the past 77 years destroyed and ignored the human rights (as we see them with our Western eyes) of its people, jailed opposition, suppressed free press, and supported dictators (like the ones who govern Iran, North Korea, and Russia). Then there are the territorial claims in the South China Sea (Spratly Islands), and its heavy handed attitude with South Korea, and Japan. Add to that the official silence over the origin of the Covid-19 pandemic, and how it has gradually eroded the rights agreed upon with Britain for Hong Kong ("One country, two systems", for 50 years) and is slowly but surely imposing its totalitarian views and police-state grip there. The increasingly aggressive stance with Taiwan, the Republic of China, a thriving democracy, is also troubling.

Nevertheless, I am glad that research is uncovering new findings in China. This will help us understand how our ancestors peopled Asia, America, and the interplay between the different branches of hominins.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 

The Three Out Of Africa Migrations

I came across research by J. H. Relethford, who in a paper published in Nature in 2008 cites Templeton's work about the different expansions of our ancestors out of their African homeland.

The Archaeological Evidence

The fossil evidence shows that H. georgicus and H. erectus lived in Eurasia roughly 1.7 million years ago, and that there were different hominins in that region since then. The remains of H. heidelbergensis, Neanderthals and Denisovans also show evolution and possibly other out of Africa events around 600 ky ago. Finally our own branch, H. sapiens left Africa possibly twice, an early, "failed" migration around 250-100 ky ago and the final move that established modern humans around the world ~60 ky ago. At least, that is the official account.

The Genetic Confirmation

What is interesting is that genetic analysis done by Templeton confirms these dates. Again, I wonder if this fit between the data in the genes and the bones and stones is real, or was somehow eased with the foreknowledge of what had to be confirmed...

Below Is what Relethford wrote, including his citation of Templeton:

"The most comprehensive of these analyses has been performed by Templeton (2005, 2007) who examined 25 DNA regions: mtDNA, Y chromosome DNA, 11 X-linked markers and 12 autosomal markers using a 6-Myr-old date for the human–chimpanzee divergence for calibration. Using a method known as nested-clade phylogeographic analysis, Templeton found that 15 of these markers showed evidence of geographic expansion. The estimated ages of range expansion vary significantly across these markers and do not fit a model of a single expansion, but instead cluster into three groups: (1) an expansion out of Africa 1.9 Myr ago (95% CI=0.99–3.10 Myr), (2) an expansion out of Africa 650 000 years ago (95% CI=390 000–970 000 years ago) and (3) an expansion out of Africa 130 000 years ago (95% CI=9600–169 000 years ago)."

These three events coincide with the H. georgicus and H. erectus, the Neanderthal, and the H. sapiens migrations! I find the confidence intervals rather large (0.9 to 3.1 million years for erectus, 390-970 ky for Neanderthals and 9.6 to 169 ky for us). Such large intervals reveal a high uncertainty in the statistical analysis.

Is this a Coincidence? or do genetics and hard archaeology agree with solid evidence?

Relethford warns that: "Given the large confidence intervals typical of coalescent analysis, this correspondence should be taken as suggestive and not conclusive, but the apparent congruence of the fossil and genetic records is interesting and deserves continued attention, particularly as data on more low-recombination DNA regions become available."

Note that word of caution about Templeton's findings. John Henry Relethford originally was a staunch supporter of the Multiregionalism theory (humans evolved in parallel in the Old World and intermingled) and rejected the initial Out of Africa theory which suggested a total replacement of other hominins by modern humans as they marched across Eurasia, wiping them out. He later shifted to a compromise theory (Mostly Out of Africa) where there was an interplay between African H. sapiens and the hominins in Eurasia. He was concerned with the fate of these Eurasian people.

Alan Templeton on the other hand adopted a rigid position against the replacement Out of Africa theory, criticizing it. His papers reflect this (see above), and he continued with another paper in 2013, and again in 2023, supporting his point of view.

Templeton wrote a very interesting critique about some statistical tools, and admixture trees, which will be the subject of a future post.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2025by Austin Whittall © 

On the Diversity of Africans

In a recent post I wrote about the Neutral Theory of molecular genetics, and its shortcomings. Today's post will explore the African genetic diversity, a foundation on which the Out Of Africa (OOA) theory is based.

There are several questions that should be answered: Do modern Africans reflect the genetic makeup of ancient Africa 100,000 or 75,000 years ago? Is a modern Nigerian, Gambian, Angolan African representative of the ancient population from which the Out of Africa migrants split? Have other events taken place within Africa in other populations that were isolated from the sub-population that was the root or base from which modern H. sapiens migrated into Eurasia?

Admixture with archaic hominins after the OOA event (such as H. naledi), admixture between many separate and formerly isolated hunter gatherer sub-populations due to migrations like the Bantu migration could have led to a modern highly diverse African population, while the original OOA root was far less diverse.

The image below is a crude attempt to reflect the isolated populations within Africa at the time modern Humans appeared. Each circle is a population. They all contain allelles (colored red, blue, yellow, etc.) some shared, others unique to each population. The black arrows show the migration Out of Africa, with humans dispersing across Eurasia towards Siberia, Europe and Oceania, and America. They lose diversity on the way due to Genetic Drift.

The dashed red arrows converging on a circle shows the internal migrations within Africa by which these formerly isolated sub-populations of humans admixed and the final, contemporary population has an even higher diversity than the original root of the Out of Africa migration (set in the horn of Africa).

It does not show any back-flow of humans from Eurasia into Africa, or archaic introgression either in Africa or in Eurasia (Neanderthals, Denisovans).

Genetic Drift out of Africa. Copyright © 2026 by Austin Whittall

Population structure in Africa

The humans in Africa were not a uniform population. A paper published in Nature suggested that there were "low levels of gene flow among archaic populations before the emergence of anatomically modern humans — that is, they imply the existence of ancestral population structure." It also hints at admixture with primitive, archaic, hominins in Africa: "There is also growing evidence that some highly divergent genetic lineages might have entered our genome through hybridization between an expanding anatomically modern human population and archaic forms of humans."

Another article published in Nature, questions the use of modern Africans to model the OOA event. While highlighting the high diversity within Africa, the paper also states that "we will need to establish whether selection has continued to operate effectively on complex traits, leading to unbiased estimates from these populations. If not, it may still be inappropriate to use a specific modern African population as a proxy for the ancestral population of modern humans."

Additional research (Source) looks into the effects of the structured population within ancient pre-OOA Africa: "Several studies have indicated that ancestral populations were geographically structured before modern humans migrated out of Africa. For example, it has been suggested that the deep coalescence times of mtDNA and X-chromosome lineages are consistent with a demographic scenario of ancient population structure in Africa. A recent analysis of cranial shape variability in anatomically modern human fossils (dating to 200–60 kya) from Africa and the Middle East also reported a high level of morphological divergence among these fossil hominids which was interpreted as evidence for ancestral population structure in Pleistocene Africa. Thus, arguably, a considerable amount of genetic and phenotypic diversity may have been present at an early stage of modern human evolution."

Indeed! And not all of this diversity was found in one population, each sub-population had their own alleles, later admixed into modern Africans (minus alleles lost due to genetic drift) and plus backflow from Eurasia with introgressed Neanderthal genes, and the mutations added by an additional 100 ky of evolution in Africa, subjected to natural selection and random mutations over that period of time.

This paper also mentions the backflow: "The reverse migration of non-Africans into Africa was also shown to contribute to the gene-pool of modern African populations"

The variations observed in skulls mentioned above was reported by a paper published in Nature. Different skull shapes mean that different sets of genes were working and they were not the same alleles in each sub-population.

"Late Middle Pleistocene (LMP, from 350 to 130 ka) African fossils [were highly variable]... Even when excluding the H. naledi material, African LMP fossils exhibit extremely variable morphologies. The Omo I22 and Herto specimens have a modern-like anatomy... and are generally considered the earliest undisputed remains of H. sapiens. All other LMP African fossils show a mosaic of derived and archaic characters. For instance, the Jebel Irhoud remains were originally described as showing strong similarities with Neandertals, while the study of the new Irhoud remains emphasises their affinities with H. sapiens, despite the absence of key modern humans apomorphies. The Guomde, Ngaloba, Eliye Springs and Florisbad specimens along with Omo II... have been mostly referred to as ‘archaic H. sapiens’, a category grouping isolated fossils with disparate morphologies. This situation challenges any attempt at identifying the evolutionary mechanisms that may explain the morphological pattern in the African LMP fossil record, as well as identifying the ancestral population, or populations, of modern humans"

The Admixture Within Africa

These different groups of humans must have later admixed into the base from which modern Africans come from. Possibly after the basal Homo sapiens left Africa in its OOA journey.

Yet another paper from Nature investigated contemporary African diversity. It looked at the genes and ancient migrations in different populations, including the Hunter gatherers (HG) and the supposedly most ancient group of humans, and the most diverse one, those living in sub-Saharan Africa (SSA), to define the current genome of Africans. It found an important effect from Eurasian admixture and a strong influence of natural selection modelling modern genes:

"Eurasian ancestry has a substantial impact on differentiation among SSA populations...
We found evidence for historically complex and regionally distinct admixture with multiple HG and Eurasian populations across SSA. Specifically, ancient Eurasian admixture was observed in central West African populations (Yoruba; ∼7,500–10,500 years ago), old admixture among Ethiopian populations (∼2,400–3,200 years ago) consistent with previous reports, and more recent complex admixture in some East African populations (∼150–1,500 years ago). Our finding of ancient Eurasian admixture corroborates findings of non-zero Neanderthal ancestry in Yoruba, which is likely to have been introduced through Eurasian admixture and back migration, possibly facilitated by greening of the Sahara desert during this period.
We also find evidence for complex and regionally distinct HG admixture across SSA, with ancient gene flow (∼9,000 years ago) among Igbo and more recent admixture in East and South Africa (multiple events ranging from 100 years ago to 3,000 years ago), broadly consistent with historical movements reflecting the Bantu expansion. An exploration of the likeliest sources of admixture in our data suggested that HG admixture in Igbo was most closely represented by modern day Khoe-San populations rather than by rainforest HG populations.
Positive selection in SSA
We examined highly differentiated SNPs between European and African populations, as well as among African populations to gain insights into loci that may have undergone selection in response to local adaptive forces. To account for confounding due to Eurasian admixture, we also conducted analyses after masking Eurasian ancestry. On examining locus-specific Europe–Africa differentiation, enrichment of loci known to be under positive selection was observed among the most differentiated sites (P = 1.4 × 10−31). Furthermore, there was statistically significant enrichment for gene variants among these, indicating that this differentiation is unlikely to have arisen purely from random drift..."

So modern African diversity is the result of recent admixture across the continent and the forces of natural selection. These people are not the same people that saw the OOA migration depart.

Archaic introgression in Africa

Regarding introgression of archaic human in Africa, I had posted back in 2019 about it (See post: Archaic Ghost population admixed with Modern Humans in Africa) which quotes a paper by Lorente-Galdos et al. that reported that: "We identify the fingerprint of an archaic introgression event in the sub-Saharan populations included in the models (~ 4.0% in Khoisan, ~ 4.3% in Mbuti Pygmies, and ~ 5.8% in Mandenka) from an early divergent and currently extinct ghost modern human lineage."

Another paper form 2020, published in Science found the same effect in Western Africa: "We provide complementary lines of evidence for archaic introgression into four West African populations. Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans. Using a method that can identify segments of archaic ancestry without the need for reference archaic genomes, we built genome-wide maps of archaic ancestry in the Yoruba and the Mende populations. Analyses of these maps reveal segments of archaic ancestry at high frequency in these populations that represent potential targets of adaptive introgression. Our results reveal the substantial contribution of archaic ancestry in shaping the gene pool of present-day West African populations."

This introgression took place in West Africa after the OOA: "the admixture time ... 43,000 years B.P. (95% HPD: 6000 to 124,000), and the admixture fraction ... 0.11 (95% HPD: 0.045 to 0.19).", that is 11% mean (4.5 to 19%). And then subject to selection as it was an adaptive introgression.

This surely contributed to the diversity of the alleles in these people compared to those who left Africa in the OOA migration.

Other confounders

Finally, there is the question of back-migrations from Eurasia into Africa. These people who returned "Into Africa" or "Out of Asia" back flow carried with them genes from people who had left Africa, plus admixture with Neanderthals (and maybe, Denisovan, ultra-archaics, first wave humans who left before the final OOA event). This surely contributed to the genetic diversity of Africa.

Another element to consider is the mutation speed or faster evolutionin Africa which could have fueled diversity starting even before the final OOA event 60-100 ky ago. But that is the subject of a future post.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 

The D9S1120 9-repeat allele: unique to Amerindians?

There is a particular genetic signal that is unique to Native Americans and is only found among some Western Siberian groups, it is thd 9-repeat allele. As with all unique Amerindian traits, I wonder why was it lost elsewhere and conserved in America.

A paper by Kari B. Schroeder et al., (2009) [Haplotypic Background of a Private Allele at High Frequency in the Americas. Mol. Biol. Evol. 26(5):995–1016. doi:10.1093/molbev/msp024.🔓] looked into its uniqueness and tried to explain why it is exclusive to a specific geographic region, and where, and when did it originate.

The paper notes the presence of a "high-frequency private allele, the 9-repeat allele at microsatellite D9S1120, in all sampled Native American and Western Beringian populations has been interpreted as evidence that all modern Native Americans descend primarily from a single founding population... All chromosomes with the 9-repeat allele share the same haplotypic background in the vicinity of D9S1120, suggesting that all sampled copies of the 9-repeat allele are identical by descent. Ninety-one percent of these chromosomes share the same 76.26 kb haplotype, which we call the "American Modal Haplotype" (AMH)." (underlined is mine).

Interstingly this AMH is found elsewhere at low frequencies (7.44%) versus 39.39% in the Americas and Western Siberia. The paper suggests that this "dramatically higher frequency of the AMH in populations possessing the 9-repeat allele is consistent with the high frequency of the 9-repeat allele in these populations and with the presence of the 9-repeat allele on the AMH." Suggesting a link between both AMH and the 9-repeat allele.

The AMH vairant is found at the following frequencies elsewhere:

• 12.63% South Asia
• 5.79% in East-Central Asia
• 9.54% in Europe

It is an out of Africa mutation because "the AMH was only observed on a single chromosome in Africa, in the Mandenka population" (they live in Western Africa: Senegal, Ivory Coast, Gambia). Interestingly, "it was not observed in Oceania."

What is the 9-repeat Allelle?

The 9-repeat allele, or "9RA" is located at a specific spot on chromosome 9, (called a locus), known as the D9S1120 locus.

It is a short tandem repeat or STR or "microsatellite", which means that 2 to 6 base pairs of DNA sequence are repeated several times, in this case, nine times. Base pairs, these bases are the building blocks of DNA, made of nitrognous bases: Adenine (A), Guanine (G), Thymine (T), and Cytosine (C). They link A with T and G with C. Below is an example, the base pairs GA and TA 2bp-long is repeated four times (top). There are processes by which they can expand by mutations (in this case, from 4 to 8 repeats as shown on the bottom of the image). They can also contract, say from 12 repeats to 9, a "slippage diminution" mutation (More on this below).

Repeated base pairs (STR). Copyright © 2026 by Austin Whittall

Many Repeats!

As Fig. 4 in the paper shows, the 9-repeat is one of many. See Fig. 4 below: The caption is important, it reads "(A) Native American and Western Beringian populations and in (B) Asian populations. Only populations in which the AMH was observed are shown. The overall height of the bars represents the total frequency of the AMH by population."

The study noted that the AMH occurs with a 12-repeat allele in 62% of the sampled populations of South Asia. It is the shortest allele outside of America-Western Siberia found at frequencies higher than 1%. As you can see, there are 10, 4, 15, 16, 17, 19, etc. repeats across the globe.

The authors suggest that the 12-repeat lost 3 of them to become the 9-repeat found in Amerindians: "...the 12-repeat allele is the shortest allele that could have been ancestral to the 9-repeat allele. It is possible that a longer allele was ancestral to the 9-repeat allele... Because STR contractions greater than three steps are less likely than three-step contractions (Xu et al. 2000), we therefore view the 12-repeat allele as the most likely ancestor for the 9-repeat allele. Given that the 12-repeat allele on the AMH is most frequent and widespread in South Asia, the mutation that resulted in the 9-repeat allele possibly occurred in an ancient population that shared relatively recent ancestry with the ancestors of modern South Asians."

This loss (from 12 to 9 repeats), is called a "slippage-diminution mutation" or a "contraction via slipped strand mispairing" or "polymerase slippage". This mutation reduces the numbers of repeats and can happen spontaneously in a random manner (See Phillips, C. et al. (2008), D9S1120, a simple STR with a common Native American-specific allele: Forensic optimization, locus characterization and allele frequency studies, Forensic Science International: Genetics, Vol 3:1, 7. 13🔒)

Origin

Based on the fact that the 12-repeat allele is the most frequent one in the Old World, the authors ask where did it come from? Their answer is the following:

"The relatively low frequency of the AMH and the absence of the 12-repeat allele on the AMH in East-Central Asia have potentially interesting implications for our current understanding of Native American source populations. The frequency of the AMH in South Asia is more than twice that in East-Central Asia. Although the highest population frequency of the AMH outside of the Americas/Western Beringia is observed in the Uygur, a group of Turkic speakers who live primarily in northwestern China, and in Mongolians sampled in Outer Mongolia, the AMH reaches similarly high frequencies in populations farther to the southwest (Burusho, Kalash, and Sindhi of Pakistan). Moreover, across the world, the shortest alleles on the AMH (aside from the 9-repeat allele) are widespread in South Asia and in the Middle East."

This is interesting! its origin is to the south and west of the supposed Siberians that peopled America! The authors add:

"The possible origin of the 9-repeat allele on the AMH in a population that shared recent ancestry with the ancestors of modern South Asian populations suggests an early divergence of the ancestors of modern Native Americans from those of modern Asian."

Age

The paper then considers its age, which is always a problem, because the scholars have to fit this date somewhere between 13ky (the orthodox date for the entry into America) and 40ky (the date when humans reached eastern Asia on their way to America).

Their first "simple point estimate was 8,699 generations. Then they computed and calculated (i.e. fiddled with the data) and "Under the different best models, the mean TMRCA of the 9-repeat allele ranged from 293 generations to 1,596 generations; using a generation time of 25 years resulted in a TMRCA of 7,325–39,900 years ago."

Intersting how their Best models agree with the orthodox window of 13 - 40 ky!! for the arrival of modern humans in western Siberia and their entry into America.

They continue and refine the timeline: "Averaging over all of our best models, the mean TMRCA is 513 generations ago or about 12,825 years ago. The 95% confidence intervals for all of the best models produced ages for the MRCA of the 9-repeat allele, that range from 144 to 1951 generations ago, or approximately 3,600–48,775 years ago."

And conclude, conveniently, that: "Our point estimate of 12,825 years is also similar to recent estimates from mtDNA data, using a substitution rate based on an internal rather than interspecific calibration, for a population expansion in the Americas between about 10,000 and 12,000 years ago."

But with the simple point estmate of 8,699 generations the age would have been: 217,475 years BP, and furthermore, the paper states that "Our less conservative estimate of eight recombination events since the MRCA of all sampled copies of the 9-repeat allele doubles the genealogy length for the 9-repeat allele to 17,426 generations." This would mean an age of 435,650 years!

These two older dates of 217 and 435 ky are far older than the accepted date for Modern Humans in East Asia, but fine if we consider Denisovans or Neanderhtals. Were they the source of thiss 9-repeat allele in our autosomal DNA?

Beringian isolation - again!

They also justify the Beringian standstill theory! "our observations are best explained by a period of isolation for the founding population, during which multiple mutations may have reached a high frequency and some loci may have experienced multiple mutations, followed by a range expansion".

Natural Selection

If this 9-repeat allele gave those carrying it a better chance at surviving and passing it on to their offspring, you would expect natural selection to act, increasing this allele's frequency (as it did in Amerindians) within the population. However, the authors state that they did not find andy selection forces acting upon it.

The repeat is found on chromosome 9, and the notation to define its location is 9q21.31. This means it is on the long (q) arm of chromosome 9, within band 21, sub-band 3, sub-sub-band 1).

The paper states that "high-density genomic data... has led to the detection of regions of the genome that show potential evidence of natural selection. Analyses of such data have not identified any regions on 9q21.33 that show strong evidence of selection... In conclusion, there is no evidence from functional considerations that would lead to a hypothesis of selection in the region of D9S1120 for Native Americans."

Further on, however they revisit natural selection: "One could imagine that the 9-repeat allele rose to high frequency, due to positive selection, in a population ancestral to both modern Native Americans and Western Beringians prior to an expansion into different habitats within the Americas. However, this scenario would still support our primary assertion that the distribution of the 9-repeat allele is best explained by descent from a single population. Hence, in the absence of compelling evidence for selection, the existence of plausible neutral models by which the observed distribution of the 9-repeat allele could have occurred suggests that the simplest explanation for the unusual distribution of the 9-repeat allele is that all Native American and Western Beringian populations have inherited a very large portion of their ancestry from a single population."

My Comments

This final phrase "a single population" and the age that was omitted (200 - 400 ky) points at an ancestor of modern humans, found in Southern, Eastern, and Central Asia, the Denisovans. They also admixed with Neandertals who could have contributed to the presence of this allele in Europe and the Levant.

Regarding Natural Selection, the gene closest to the 9-repeat is AGTPB1, shown in Fig. 2C in this paper. This gene is critical for correct neurological functions, and also "In addition to its role in neuronal maintenance, AGTPBP1 is critical for spermatogenesis; disruption in its function leads to defects in germ cell development and male infertility" (Source). If the repeat somehow preserved these functions, it would make it a target for selective pressure (ensuring fertility and brainpower).

The presence in one Western African is intriguing. Its absence in Polynesians too! Did it come from some archaic hominin in Africa, at very low frequencies and is found at extremely low proportions in Africa. The first Out Of Africa event (that led to H. georgicus) probably took the AMH variant with it. It survived in Eurasia, did not make it into Melanesia or Polynesia, but was carried across Siberia into America before the arrival of modern humans. That is why it is only found in America (the Western Siberians are surely a back migration).

Did Denisovans or Neandertals carry it? Is it found in ancient remains of Amerindians? At what frequency? Did the "Great Dying" after 1492 increase its prevalence or was it always high? These are some questions that may clarify the history of this allele.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall © 

Asian evolution of Hominins (2024 paper)

Today's post shares a paper on the dispersal and evolution of hominins in Eastern and Southeastern Asia. It has plenty of interesting insights on the time line and geographic dispersal of our ancient ancestors in Asia.

The paper is the following: Rikai Sawafuji, Takumi Tsutaya, Naoyuki Takahata, Mikkel Winther Pedersen, Hajime Ishida, (2024). East and Southeast Asian hominin dispersal and evolution: A review. Quaternary Science Reviews. Volume 333, 1 June 2024, 108669. https://doi.org/10.1016/j.quascirev.2024.108669.

It summarizes current knowledge, and theories, as well as suggesting some future research avenues. A very good paper!

I enjoyed the description of Homo erectus. This hominin has always fascinated me since I was a teen, when I read about it in my elder sister's highschool biology book (no internet in the 1970s). At that time there was the Peking Man, and the Java Man from Solo Rivr, and no African erectus. I also read about the Rhodesia Man, Neanderthals, Cro-Magnons, and the Australopithecines in Africa, more primitive and smaller. It seemed a complex mixture of different people. Now, over 50 years later, the panorama is still obscure!

"There are various views on the classification of H. erectus, e.g., H. erectus from Africa as a separate species called H. ergaster (Tattersall et al., 2015). In this review, we use the broader definition of H. erectus (H. erectus sensu lato) and consider the African H. erectus as part of the same taxon.
H. erectus is currently recognized as the first hominin to spread out of Africa and is thought to have migrated eastward across Eurasia and then southward into Southeast Asia. The fossil records are concentrated in Europe, China, and Java, with little data available for the intermediate areas.
Some of the earliest probable fossils of H. erectus are the ∼2.04 Ma cranium found at Drimolen, South Africa (Herries et al., 2020) and ∼2 Ma mandible at Melka Kunture, Ethiopia (Mussi et al., 2023), while the earliest generally accepted evidence of their presence out of Africa was discovered at Dmanisi, Georgia, and dated to ∼1.8 Ma (Ferring et al., 2011; Lordkipanidze et al., 2013).
In China, recent findings have suggested an earlier hominin presence although the evidence is scarce and primarily based on stone tools found at Shangchen, dated to ∼2.1 Ma (Zhu et al., 2018), and on hominin teeth dated between 2.42–1.8 Ma at Jianshi-Longgu Cave (Li et al., 2017a). These findings, which might predate the Dmanisi fossils, suggest the intriguing possibility that either H. erectus or another hominin arrived in China earlier than the time of Dmanisi (Cartmill and Smith, 2022). However, due to the scarcity of comprehensive fossil records, these conclusions must be approached with caution, as definitive identification of these early hominins in China remains challenging.
Fossils and lithics of likely H. erectus found in China include ∼1.66 Ma stone tools from Majuangou III in the Nihewan Basin (Zhu et al., 2004) and 1.7–1.6 Ma stone tools from Shangshazui (Ao et al., 2013), and a ∼1.63 Ma cranium from Lantian-Gongwangling, near Shang Chen (Zhu et al., 2015). Two ∼1.7 Ma incisors have also been found in Yuanmou, South China (Zhu et al., 2008), though their age determination remains questioned (Bae, 2010). Taken together with the fossil and lithic evidence, the conservative age of the emergence of H. erectus in China is about 1.7–1.6 Ma."

The interesting part is the suggestion of hominin presence in China ~2.4 to 2.1 Ma, older than the earliest South African fossils (~2.04 Ma), also that they were not Homo erectus but "...another hominin arrived in China earlier than ... Dmanisi." This could imply the presence of Homo habilis or even Australopithecines in Asia.

The following image shows how the different lineages of hominins coexisted in Asia during the past 2 million years.

Chronology of the genus Homo in EA/SEA.. Source

The image below shows the distribution of hominins in Eastern and Southeastern Asia.

The Story and Timeline of Hominins in Asia

The paper gives a brilliant description of the dispersal of hominins in East Asia and Southeast Asia.

"As more and more pieces are continuously added to our understanding of hominins, their geographical distribution and persistence, new questions arise, and details about how the different hominins dispersed and why they went extinct still remain unclear. From current fossil records and genetic evidence, one plausible and coherent scenario of hominin dispersal is the following: H. erectus emerged in Africa and expanded into the Eurasian continent around 2 Ma, later occupying Europe, East Asia (China) and Southeast Asia (Java).
Subsequently, the common ancestor of H. sapiens, Neanderthals and Denisovans split into two groups: one was in Africa (later leading to H. sapiens) and the other settled around the Middle East at some point. The latter interbred with a super-archaic hominin group (possibly H. erectus) around 700–600 ka.
The Eurasian hominin group then split into two groups. One settled in the West (Europe and Western Asia) leading to Neanderthals, while the other settled in Asia leading to Denisovans. Denisovans interbred with H. erectus in Eurasia, occupying their niche. At some point, Denisovans also expanded into East and Southeast Asia, where the groups diverged into different subgroups (D0, D1, D2, D3, the details are in the chapter of Denisovans). Meanwhile, H. erectus may have become extinct around 400 ka in East Asia and 100 ka in Southeast Asia. Denisovans reached the Altai region, eventually meeting and interbreeding with Neanderthals several times around 140–80 ka. Meanwhile, some H. sapiens left Africa before 200 ka. This initial migration was unsuccessful, but interbreeding with Neanderthals at this time left traces in their genome (Peyrégne et al., 2023). There were several subsequent out-of-Africa events, which might have reached Asia, but the populations that led to our ancestors left Africa around 55 ka. They interbred with Neanderthals in West Asia and with Denisovans in EA/SEA. Note that we consider the super-archaic hominin contributing to the Denisovan genome to be H. erectus. While there is a possibility that hominins other than H. erectus and Denisovans migrated into Asia or evolved from H. erectus, this is not considered here due to the lack of evidence."

The suggestion that (no date given for this event) the ancestor of modern humans, Neanderthals and Denisovans moved out of Africa, settled in the Middle East and some 700-600 ya mating there with H. erectus is very interesting!

The further admixing of Denisovans with erectus as they moved across Eurasia is not often mentioned. And the final comment that "... there is a possibility that hominins other than H. erectus... migrated into Asia or evolved from H. erectus," is worth exploring as there is no evidence to prove it happened. But, it is possible and likely.

The paper also has some interesting comments on the four lineages of Denisovans (with a neat map), and their history:

Denisovans

"The common ancestor of Denisovans and Neanderthals which occupied around the Middle East interbred with a super-archaic hominin, and afterwards the Denisovan ancestors diverged from the Neanderthal ancestral group and moved into Asia. Some of them spread towards Papua and settled in Island Southeast Asia (D1). Another group remained in South or Southeast Asia (D2), and from there, another group moved further north into East Asia (D0, D3). During the early phase of this migration, they encountered a super-archaic hominin population and interbred. The D0 group settled somewhere in East Asia. The D3 group reached the Altai in Siberia (D3), where they met and interbred with Neanderthals."

The section dedicated to small-sized hominins Homo floresiensis and Homo luzonensis is great, I learned that the latter's "finger and toe bones are elongated and curved, a feature similar to australopithecines". Nevertheless, evidence suggests both "tiny" hominins may descend from H. erectus.

Ancient Mariners

It is remarkable that these two groups of people (and a third responsible for stone tools found in Sulawesi) crossed open sea, settled in islands, and lived there in isolation until their demise when modern humans reachd the area. Navigating abilities is something seldom discussed in any paper, including this one, which only says "Although it is unclear how each hominin crossed the sea, they succeeded intentionally or accidently"

It is evident that even archaic forms of hominins like erectus crossed open sea. Could they have reached America? (See my post about their navigating skills, and this post on Neanderthal "sailors").

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2026 by Austin Whittall ©