Cranial shapes, OOA, Denisovans, Melanesians & Australians

A research paper published back in 2022 (Matsumura, H., Tanijiri, T., Kouchi, M. et al. Global patterns of the cranial form of modern human populations described by analysis of a 3D surface homologous model. Sci Rep 12, 13826 (2022). https://doi.org/10.1038/s41598-022-15883-3), compared the skulls of contemporary human populations from Africa, Europe, Asia, Americas, Melanesia-Australia, etc., finding some interesting traits.

Modern human skulls differ

The paper relies heavily on PCA data, which, as per my last post, may not be the most suitable tool to emply in studies like this one, which is, basically, morphometric, as it compares skull dimensions and reduces these different data values into several Principal Components).

The PC4 and PC2 (principal components 2 and 4) analysis shows that there are distinct groups: Africans overlapping Australo-Melanesians (see the lower image below, pink and red ovals on the right side), Northeastern Asians (green oval, bottom left), and Europeans (blue oval, top left). There are other populations as you can see in the upper image (Middle East, South Asians and Americas), but they are not shown as distinct groups in the second, lower, image.

Scatter scoring diagrams of PC2 and PC4 for cranial individuals from nine geographical units (upper), and four geographical units (lower), color maps of cranial surface highly correlating vertices to each PC. Fig 4. in Matsumura et al., 2022

Australo-Melanesian skulls are similar to African ones

The grouping toghether of two populations separated by an Out of Africa (OO) walking distance of 20,000 to 24,000 km (12,000 to 15,000 mi.) is indeed surprisin. But the authors point it out: "Australo-Melanesian (including Papuan) samples exhibited a closer resemblance to African samples than any other geographic series in the PCA of the homologous model." And they also explain it as if it was a normal consequence of such a vast trek: "This finding supports the hypothesis that the first dispersal group of AMH along the southern rim of Eurasia was of direct African origin."

But, if, as we now know, that Papuans and Melanesians have the highest levels of Denisovan admixture of all the global populations. Why would they carry 5% of Denisovan genes and still display a skull shaped like an African?

The paper states that Australo-Melanesians have a "large" AUC, comparable to Sub-Saharan Africans which also have large AUCs. They also share (this is the dimension marked by the PC2 axis) a "relatively longer neurocrania than the others... which describes the close affinity between the proportionally elongated crania of Australo-Melanesians and Africans and dissimilarities with the globular crania of some Europeans and Northeast Asians." Note that AUC is a metric (Area under the curve —AUC, in an ROC Receiver Operating Characteristics Analysis. A lot of jargon!)

The paper includes many comments on the differences between modern human skull shapes, and when it comes to the Australo-Melanesians explains it as follows. The authors mention the possibility of two OOA events, an ancient one, some 177,000 years ago, which led to anatomically modern humans out of Africa and into the Levant and Mediterranean basin, but whether these people expanded into Eastern or Southern Asia is still unknown. The other option is a recent wave (60,000 years ago) out of Africa along the Indian Ocean coastal regions towards Southeast Asia, Papua, and Australia. This was followed by other waves into North-Central Asia and Europe.

The paper adds that the similar appearance of African and Papuan-Australian crania was the result of this first migration along the Indian Ocean, which "...was of direct African origin, without significant morphological alterations in accordance with a particular climate or other substantial conditions" (they note the climate, becaus the attribute the shape differences of other humans to adaptation to colder climes).

Denisovans

Denisovans admixed with Melanesians, and Papuans exhibit a high proportion of Denisovan alleles. Denisovan skulls are very different from ours (Source) but they are do have a long skull like Austro-Melanesians: "...long and low cranial vault, a wide and low face, large and almost square orbits, gently curved but massively developed supraorbital torus, flat and low cheekbones with a shallow canine fossa, and a shallow palate with thick alveolar bone supporting very large molars."

But, Denisovans are Asian hominins, they never entered Africa. So, why do Africans share this long skull too?

Controversial pro-China, sinocentric scholar Shi Huang argues that the OOA theory is wrong, ant that "An alternative worth testing is my proposal that Australo-Melanesians, including Papuans, retain unusually high Denisovan ancestry, and that Denisovans ultimately trace to an African-related archaic lineage. Under that model, the otherwise striking African–Australo-Melanesian cranial affinity could reflect shared archaic ancestry rather than simply an early modern-human migration out of Africa."

Reasonable. Neanderthals and Denisovans are said to have split from the modern human lineage within Africa, exiting the continent around 600,000 years ago. Denisovans are not supposed to have back-migrated into Africa. Probably the human group that led to Australian and Melanesians carried a higher content of pre-split alleles than other humans who moved north into western Eurasia.

Another possibility is that humans originated in Eurasia, and migrated from there. One group, with the Australian-Melanesian trait moved into that region and also into Africa. Another moved north into Siberia, and west, into Europe. Why should we constrain our theories to the OOA one?

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

Lake Mungo man revisited: maybe the Aboriginal people were not the first to reach Australia

Back in 2001, Gregory J. Adcock, et al. published a paper (Mitochondrial DNA sequences in ancient Australians: Implications for modern human origins. PNAS, January 16, 2001 vol. 98 no. 2 537–542) reporting that the remains of a man known as LM3, found close to Lake Mungo in Australia, who lived between 40 and 68,000 years ago, carried a unique mtDNA that placed him in a lineage older than that of the "primordial Eve".

Below is a picture of LM3 at its site in Lake Mungo.

The study showed that LM3 carried a mtDNA variant that is not found in other hominin remains or in modern human beings. It became extinct (most likely because this person's lineage died out and could not pass it on to their descent). This mtDNA has survived h owever, as an insert a "chunk" of genetic material found within chromosome 11 of the human genome. Until then, scholars had asked themselves if this segment of DNA had made its way into the nuclear DNA becoming part of it. This had happened before.

T, Thorne says, is a sequence in LM3's mtDNA that differs both from that of the other fossils and from that of modern people. Now extinct in modern human mtDNA, it exists only as a remnant, or “insert,” on chromosome 11 in the modern nuclear genome. Scientists have long suspected this sequence to be a copy of old mtDNA that found its way into the cell nucleus, as other sequences are known to have done.

"“His mtDNA belonged to a lineage that only survives as a segment inserted into chromosome 11 of the nuclear genome, which is now widespread among human populations.
This lineage probably diverged before the most recent common ancestor of contemporary human mitochondrial genomes. This timing of divergence implies that the deepest known mtDNA lineage from an anatomically modern human occurred in Australia [...] This finding does not imply that all living people originated in Australia [...
Deep lineages in Africa and our finding of an even deeper lineage in Australia are consistent with a number of possible models of the demographic and evolutionary history of our species."

It showed that there was a lot of diversity that was lost during the migration of modern humans around the world. However, the Australian Aboriginal people, who are very (not to say extremely) sensitive about anything that could challenge their position as the first people to inhabit the Island-Continent of Australia, didn't like this finding.

But the paper didn't challenge the Aboriginal priority claim, in fact it stated " LM3 and his contemporaries, as well as the more recent robust KS individuals, all could have been ancestors of living indigenous Australians."

However it also mentioned the option that LM3 was a lineage that reached Australia first, but later was replaced by a second wave of immigrants. LM3 people were "modern humans [...] that were replaced and that part of the replacement occurred in Australia." This implies that the Aboriginals replaced LM3 people.

The third option was that the original people carried many mtDNA variants and that the "insert" haplotype was eliminated through selective pressure, with others replacing it due to natural selection. The mtDNA was lost, but the nuclear genes remained, and "the lineages would have been retained and may well be represented in contemporary indigenous Australians."

Two out of three alternatives favored the first arrival of Aboriginals. But they insisted it was wrong.

They campaigned and got the Australian government to have the bones reburied in the site (Source), which took place in 2022, meaning no further studies.

But before doing this, they produced a second paper (T.H. Heupink,S. Subramanian,J.L. Wright,P. Endicott,M.C. Westaway,L. Huynen,W. Parson,C.D. Millar,E. Willerslev, and D.M. Lambert, (2016). Ancient mtDNA sequences from the First Australians revisited, Proc. Natl. Acad. Sci. U.S.A. 113 (25) 6892-6897, https://doi.org/10.1073/pnas.1521066113), concluded (conveniently) that Adcock was mistaken:

"Using second generation DNA sequencing methods, we provide strong evidence that the DNA sequences reported by Adcock et al. were, indeed, contamination. Our manuscript is also important, because the research was planned and conducted and is published with the support of the Barkindji, Ngiyampaa, and Muthi Muthi indigenous groups."

Notice who planned, conducted and supported the publication! The Aboriginal groups! They demolish, as would be expected, Adcock's claims:

"As a consequence, there is no need to explain the presence of robust and gracile morphologies by invoking population replacement or selective sweeps (claim 3). We suggest that all of the sequences reported by Adcock et al. were either modern contamination or PCR artifacts. As a result, it seems that contemporary mitochondrial data are consistent with the Out of Africa theory (claim 4). Of the four Willandra Lakes samples, we show that WLH4 does contain authentic Aboriginal Australian DNA sequences, and we report the complete mitochondrial sequence from this individual."

So, they found contamination, European DNA, etc. and proved that the Aboriginals were the first and only humans in Austalia until the Dutch explorer Willem Janszoon reached it 1606.

I find the idea of a first wave of humans (maybe Denisovans, or even H. longi) reaching Australia 100 or 200,000 years ago exciting. They could have lived there and then admixed with the later H. sapiens migration, and gradually faded away, mixing time and time again with the newcomers forming the modern Aboriginal people.

But the Aboriginal people think otherwise:

"Our Aboriginal and Torres Strait Islander tribes were the first sovereign Nations of the Australian continent and its adjacent islands, and possessed it under our own laws and customs. This our ancestors did, according to the reckoning of our culture, from the Creation, according to the common law from 'time immemorial', and according to science more than 60,000 years ago."

Above is a quote from the Uluru statement from the Heart presented in 2017.

A study published last June (Jim Allen, James F. O'Connell (2025). Recent DNA Studies Question a 65 kya Arrival of Humans in Sahul. Archaeology in Oceania. 29 June 2025 https://doi.org/10.1002/arco.70002) pushed that date closer in time: earlier than 50,000 years ago. It argues that "Recent reports present evidence of Neanderthal introgression among all non-African human populations after 50 kya. Here we trace the implications of this claim for Sahul history ... Jacobs et al. (2019) identify two Denisovan introgressions involving modern humans in Sahul, the earlier one at 46 kya... If correct, ancestral Sahul populations bearing Neanderthal DNA must have arrived after this date."

Update: See this post (Dec. 20, 2025) with a recent study* about an earlier arrival of humans (Aboriginal) to Australia, and their possible admixture with archaic hominins, including the Hobbit!

* Francesca Gandini et al., Genomic evidence supports the “long chronology” for the peopling of Sahul. Sci. Adv. 11, eady9493 (2025). DOI:10.1126/sciadv.ady9493. Nov. 28, 2025

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

Austronesians and America: the Transpacific Route

A few days ago, I posted about the possibility that an ancient wave of people from what is now known as Melanesia (including Australia), reached America long before the Polynesian contact that has been suggested took place around AD 1200-1400. Today we will look into this scenario.

Polynesians are said to have originated in an "Out of Taiwan" migration that swept in a wide arch south, across the islands of Indonesia, and then across New Guinea, the Bismarck Archipelago, Bougainville, and the Solomon Islands. There they originated the Lapita Culture and established the Polynesian languages around 3,500 years ago. They then moved to the Islands southeast of the Solomons such as Vanuatu and Fiji (3,000 years ago). They stood still there for a long time before spreading into distant Polynesia around 800 AD, and Micronesia around AD 1250 their expansion ended in New Zealand.

The discovery and peopling of Eastern Polynesia required advanced sailing skills. An interesting paper delves in depth with this matter, and states that: "The immense seascape of East Polynesia and increasing contrary winds required advances in navigation and technology. The settlement of East Polynesia involved a package of technological innovations." The inner islands around New Guinea and Melanesia were easy to navigate with wind blowing in two directions, but crossing the ocean towards distant Polynesia meant sailing against the wind.

The invention of the sprit sail, more efficient V-shaped hulls (vs. U-shaped ones), and larger planked double-hulled canoes that could carry more cargo and people, all favored the exansion across Polynesia.

Peopling of Polynesia. Source. See original image

An Earlier Date for Arrivals of Human Beings the Southwestern Pacific

A study published in 2011 reports an "older" age for the first humans in the region:l

"Our results show that the maternal ancestors of most Remote Pacific islanders split from Asian mainland lineages ∼10–20 ka, rather than ∼5.5 ka, as would be the case if they were to be explained by the “out of Taiwan” model. They had established themselves in the Bismarck Archipelago by at least ∼6 ka, rather than arriving there ∼3.5 ka with the advent of Lapita pottery, as the model predicts."

This earlier date is interesting. Did these people have the seafaring abilities of the later ancestral Polynesians? Could their boats cross long ocean distances? It is doubtfull. The Aboriginal population of Australia who has lived on the Island-Continent for +60,000 years, possessed limited seafaring abilities.

See this interesting webpage with images drawn by Europeans during the discovery period (late 1700s) of the watercraft used by Aboriginal people. They used rafts, simple dugout, or bark canoes, tied-reeds, and similar rudimentary vessels, like the one picture below.

They resemble the canoes used by the Fuegian Yamaná and Alakaluf, and the Chono people of southwestern Patagonia. The reed canoes are similar to those used by the Uros of Lake Titicaca in Bolivia. This shows that the ancestral skills of making simple watercraft were shared by all ancient human beings.

They couldn't have crossed the Pacific Ocean in one of these canoes.

The "Kelp Highway"

Another route using calm coastal waters was proposed by Jon Erlandson et al in a 2007 paper (The Kelp Highway Hypothesis: Marine Ecology, the Coastal Migration Theory, and the Peopling of the Americas). In it, they put forward the theory that the kelp seaweed forests along the North Pacific coasts of Asia and North America would have allowed people to find food, on their journey from Australia to Japan, Siberia, Alaska, California. South of this point, mangroves and coral reefs replace the kelp, but, serve the same purpose, guiding the migrants into South America. This kelp highway avoids the risky transpacific oceanic route.

Interestingly, the fuegian people thrived in an area with kelp-rich waters. Kelp algae form underwater forests, which support rich marine life such as fish, sea urchins, crabs, and sea otters. In the North Pacific they were the home of the herbivore Steller's Sea Cow, extinct since the 1700s.

Kelp and seals in the Beagle Channel, Tierra del Fuego. Source

Kelp Forests around the globe. Source

An interesting theory!

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

Australian Pygmies, fact and fiction

Australian pygmies are a source of controversy because mainstream science and the Aboriginal indigenous people oppose the notion that pygmies were the first humans to inhabit the continent.

Right wing supporters on the other hand believe that the pygmies came first and that the Aborigines took the continent from the pygmies.

Their argument goes as follows: Pygmies arrived first, the aboriginal people came later and drove the pygmies to extinction, the British were just another wave of migrants doing what the aboriginal people had done before. So why should invaders such as aboriginals have more rights over the land than the British. After all, the Aboriginals took it from the original Pygmie people.

A quick online search shows that there are not many references to pygmy people in Australia. I didn't manage to find anything recorded by the first European explorers or during the period of British exploration and occupation.

Most of the literature points back to an article published in Quadrant (Keith Windschuttle and Tim Gillin, The extinction of the Australian Pygmies, 2002).

Quadrant is a right-wing magazine (see what mediabiasfactcheck.com has to say about how far to the right they are), so Quadrant would have a reason to back the pygmy theory because it undermines the aboriginal people's claims of being the first people in Australia.

My Search for Pygmies in Australia

This is what I have found out about pygmies down under:

1. Pygmies are part of the Aboriginal people's mythology.

There is an Aboriginal myth, about the origin of the platypus (Source), which mentions the "small people" or "Dinderi". They hunted water snakes in the Brisbane River in what is now Queensland, but these managed to turn them into platypuses. But does this myth mean that there were a tribe of pygmies (the Dinderi)?

You can also read about Short people in Cape York Peninsula, Northern Queensland, Australia.

2. Short stature people lived in Queensland recently.

An article titled Pygmy elder faces eviction, published in 2007 (Queensland CourierMail August 25, 2007), reported that Lizzy Woods, 105 years old, was the "... oldest surviving matriarch of the Jirrbal rainforest people. ... the sole surviving link to the pygmy 'white cockatoo' tribe – most of whom stood less than 122cm (4ft) tall – of the Misty Mountain region near Tully.
... the 110cm-tall [3.6 ft] elder [said] 'I was born in the rainforest. I grew up chasing kangaroo and picking berries off the trees. I belong here. This is my land. The pygmy tribe – that is my mob'."

3. An anthropologist also reported the Dinderi myth.

Lindsay Winterbotham interviewed an Aboriginal man born in 1887, Gaiarbaus and wrote (1957) the book "Gaiarbaus story of the Jinibara tribe of south east Queensland (and its neighbours)", it was never published, but the book exists and you can read its index online, and this index mentions: "Pygmies (Dinderi), beliefs in south east Queensland tribes".

Winterbotham was advised by Norman Tindale during his interviews, and it is Tindale who is quoted in the article published by Quadrant.

3. Tindale and the Trihybrid theory

Tindale and American anthropologist Joseph Birdsell, worked together for over 50 years, starting in 1938. They put forward the theory that: The pygmoid and negrito people(the word negrito is Spanish, and means "small black people") living in the rainforests in Northern Queensland in the 1930s were the remnants of the first wave of humans to reach the vast Australian continent. These tiny people were later pushed in to the island of Tasmania (hence the name of "Tasmanoids" that Tindale and Birdsell gave them) and the deep rainforests by two later waves of humans invading Australia.

The two scientists later renamed them "Barrinean" after Lake Barrine. Yoy can read this theory in this 1953 newspaper article.

This "Trihybrid" theory included a second wave of pale skinned "Murrayians" which were supposed to be linked to the Ainu people of Japan, and the third wave of robust dark skinned "Carpentarians" possibly linked to primitive Indian tribes.

This website has some photos of these three "types" of humans proposed by Birdsell and Tindale as the successive waves that peopled Australia.

This theory has been discredited by later research (see this paper for example), but it was not invented by Tindale, I found an earlier publication suggesting the same idea:

In Transactions and Proceedings of the Royal Society of South Australia, 1922, an article (Cylindro-Conical and cornute stones from the Darling River and Cooper Creek, Robert Pulleine. pp.304-308) mentions Albert Churchward:

"If we accept the views of Churchward, now gaining the attention of anthropologists, that mankind originated in the great lake districts of Africa, we find opened up a path which leads to an understanding of the origin of our aborigines and their beliefs. In his two books, "Signs and Symbols of - Primordial Man" and "The Origin and Evolution of Mankind," he pictures the Pygmy exodus throughout the world and their displacement and annihilation by the people of the second Nilotic exodus to which our aborigines, accord- ing to him, belong. He states that the Pygmies of the first Nilotic invasion were displaced in Australia and eventually only remained in Tasmania. "

Churchward had been writing about pygmies since the early 1900s, so he surely influenced Tindale.

4. There are "pygmies" in New Guinea

New Guinea has small people too, reported as early as 1910 (paper in Nature), as recently as 2013, and in between too (see this paper from 1961 (it mentions the trihybrid theory and Tindale).

Closing Comments

Probably different waves of humans colonized Australia, starting with Homo erectus and ending with the British. The Aboriginal people are without any doubt, the rightful original people of Australia, the first people to successfuly colonize the continent and live there for over 50,000 years. However it is also likely that other groups, linked to the Negrito people of Southeastern Asia and New Guinea also settled in Australia, whether it took place before, during or after the arrival of the Aboriginals is a trivial point.

But what if the Aboriginal myths aren't about the Negrito people, and instead refer to "small people" like the "Hobbits" of Indonesia? A distant relative of us humans.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2019 by Austin Whittall © 

On an Archaic hominin introgression in Africa and an earlier date for the peopling of Australia

Today I have come across two brand new and very interesting papers:

The first one tells us that modern Homo sapiens reached Australia much earlier than formerly believed: 65,000 years ago. (Chris Clarkson et al., "Human occupation of northern Australia by 65,000 years ago", Nature 547, 306–310, 20 July 2017, doi:10.1038/nature22968).

The authors point out that "This evidence sets a new minimum age for the arrival of humans in Australia, the dispersal of modern humans out of Africa, and the subsequent interactions of modern humans with Neanderthals and Denisovans.".

The other paper by Duo Xu et al ("Archaic hominin introgression in Africa contributes to functional salivary MUC7 genetic variation", Molecular Biology and Evolution, 2017; DOI: 10.1093/molbev/msx206.) tells us that an archaic hominin interbred with sub-Saharan Africans.

This is an extremely interesting conjecture which the authors state as follows "...we conclude that a divergent MUC7 haplotype likely originated in an unknown African hominin population and introgressed into ancestors of modern Africans...".

This introgression could explain why there is so much diversity in sub-Saharan Africans: they got it from an archaic human (I posted this same idea Here, where I wrote: "This leads me to ask, what if African heterozygosity was enriched by recent admixture with other hominins in Africa? an inflow of different relic alleles elevated African diversity above that of non-Africans" and Here where I wrote: "These ancient African humans carried the A00 lineage in them, mated with AMH (within the last 195 ky)").

The second paper is interesting and I will post on it later because it has some "orthodoxy" influencing its hypothesis, see this for instance, where the authors look into the introgressed halpogroup, (E):

"However, introgression of haplogroup E from Neanderthals or Denisovans is unlikely, because haplogroup E is exclusively found in sub- Saharan African populations, whereas introgression events between Neanderthals or Denisovans with modern humans happened after modern humans migrated out of Africa (Vernot and Akey 2014) (Figure 5A, Figure S5). As such, we hypothesize that an archaic hominin, at that time still roaming in Africa, contributed haplogroup E to the ancestors of extant Africans."

They are assuming that H. sapiens originated in Africa and moved "Out" of Africa. If they had move "Into" Africa from Eurasia, then Neanderthals or Denisovans could have been the origin of the haplogroup...

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2014 by Austin Whittall © 

The link between Negritos, Papuans and Amerindians!

At last a paper that sheds some light on the origin of Native Americans. I was pleasantly surprised to see a paper today that postulates that America had two distinct founding populations and that the older one, found in South America, is linked to Negrito people of the Andamans, Papuans, New Guineans and Australian Aboriginals.

This is the paper: Pontus Skoglund, Swapan Mallick, Maria Cátira Bortolini, Niru Chennagiri, Tábita Hünemeier, Maria Luiza Petzl-Erler, Francisco Mauro Salzano,Nick Patterson,David Reich. Nature (2015) Genetic evidence for two founding populations of the Americas doi:10.1038/nature14895 Received 05 February 2015 Accepted 14 July 2015 Published online 21 July 2015,

The paper is here LINK; the following image is the map that portrays that similarity between those groups:

Just in case you are expecting a post-discovery of American admixture of Asian genes with Amerindian ones... the paper on page 3 shows that they are closer to South East Asians Onge than to Polynesians. The closing paragraphs hint at a very ancient origin for these Amerindian ancestors and this is because though they are similar to the Andaman Negrito-Papuan group they "are not particularly closely related to any of them" and the original population that later led to these Amerindian ancestors became extinct in Asia. By the way, the Andaman natives and the Negrito people are believed to be among the oldest humans out of Africa.

Allow me to throw a wild idea: how can we be sure the flow was from South east Asia to America and not the other way round? an Out of America move from a basal archaic population that lived in the Americas?

And I recall my post on Y chromosome Haplogroup C, which is present in America at low frequencies and... also found in SE Asia.

It is indeed an interesting discovery and is I believe related to the recent paper on the Botocudos, which I wrote about a few weeks ago: "Put together we could conjecture that the old human lineage that peopled Asia reached the New World long before later East Asian or Siberian waves got there. That they are found in some secluded parts of America. They are old, and linked to Melanesia, Australia (whose inhabitants recently moved across the Pacific peopling Polynesia)."

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2015 by Austin Whittall © 

Denisovans Amerindians and Austronesians

A paper by Pengfei Qin and Mark Stoneking (Denisovan Ancestry in East Eurasian and Native American Populations bioRxiv preprint first posted online April 3, 2015; doi: http://dx.doi.org/10.1101/017475), takes a look at the Denisovan content in modern Homo sapiens genes.

Below is one of the maps posted in the supporting information (from page 8) which shows (blue shades) the higher introgression of Denisovan DNA into humans in Australia, New Guinea and Melanesia, while the Neandertal content is given by the red shades (higher in Asia, America and Europe. Green tint is the neutral African area.

Neandertal and Denisovan DNA in modern humans. From Fig. S4 B in Pengfei and Stoneking.

They put forward two possible ways for the admixture of Denisovan and Homo sapiens genes. Allow me to quote them:

"However, there are (at least) two potential alternate scenarios that could explain these results. First, Denisovan admixture could have occurred in a population that was ancestral to both EE/NA (East Asia and Native American) and Oceanian populations; second, admixture could have occurred in a population that was ancestral specifically to Mamanwa, Australians, and New Guineans (as suggested previously (2)), followed by a back-migration from New Guinea to mainland East Asia. This putative back-migration would then have spread both New Guinea and Denisovan ancestry throughout East Asia and Siberia, and ultimately to the Americas."

The first option (admixture in Siberia near Denisova), would be followed by additional dilution in East Asia of Denisovan genes when more modern humans migrated into East Asia and admixed with the population that had originally received the Denisovan input. While this did not take place in Oceanian peoples.

In my opinion the back-migration out of Australia is unlikely. But what if... there was a sizeable populations of Denisovans in South East Asia and Sahul. Humans arrived and mixed with them. The higher the density of Denisovans or ratio of Denisovans to H. sapiens, the higher their "input" of genes into the mixed offspring of human - Denisovan matings. So PNG, Australia had a higher ratio of Denisovans than East Asia... or America (why must we always assume that the introgression took place once in one place?). Because admixture could have taken place in several locations: America, Asia and Austronesia.

Who are these Denisovans? The most likely candidate is an ancestor that lived in Asia and had left Africa before Humans and before Neandertals... that spells Homo erectus. They did live in Sahul and China (maybe America but that is not considered by mainstream science).

The interesting thing is that Neanderthal (see the red hues in the map above) genes are very strong in America among Native Americans too, suggesting (a) Modern Humans mixed with them in Asia and brought the Neandertal genes with them into America or (b) Admixture took place in America: modern humans met and mated with Neandertals in the New World.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2014 by Austin Whittall ©