Denisovan
The first identification of a Denisovan individual occurred in 2010, based on mitochondrial DNA (mtDNA) extracted from a juvenile female finger bone excavated from the Siberian Denisova Cave in the Altai Mountains in 2008.
DNA evidence suggests they had dark skin, eyes, and hair, and had a Neanderthal-like build and facial features.
Denisovans apparently interbred with modern humans, with a high percentage (roughly 5%) occurring in Melanesians, Aboriginal Australians, and Filipino Negritos.
[4] Chinese researchers suggest the Denisovans were members of Homo longi, and the idea has been supported by the palaeontologist Chris Stringer.
[9] The specimen was originally named X-woman because matrilineal mitochondrial DNA (mtDNA) extracted from the bone demonstrated it to belong to a novel ancient hominin, genetically distinct both from contemporary modern humans and from Neanderthals.
[15] It was determined by ancient protein analysis to contain collagen that by sequence was found to have close affiliation to that of the Denisovans from Denisova Cave, while uranium decay dating of the carbonate crust enshrouding the specimen indicated it was more than 160,000 years old.
[16] The identity of this population was later confirmed through study of environmental DNA, which found Denisovan mtDNA in sediment layers ranging in date from 100,000 to 60,000 years before present, and perhaps more recent.
Dental proteome analysis was inconclusive for this specimen, but the team found it anatomically comparable with the Xiahe mandible, and so tentatively categorized it as a Denisovan, although they could not rule out it being Neanderthal.
[14] In 2021, Chinese palaeoanthropologist Qiang Ji suggested his newly erected species, H. longi, may represent the Denisovans based on the similarity between the type specimen's molar and that of the Xiahe mandible.
[24] In 2024, Bae and Wu suggested classifying the Xujiayao and Denisovan material as H. juluensis, and the Dali Man and similar specimens as H.
Sequenced mitochondrial DNA (mtDNA), preserved by the cool climate of the cave (average temperature is at freezing point), was extracted from Denisova 3 by a team of scientists led by Johannes Krause and Svante Pääbo from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
Krause and colleagues then concluded that Denisovans were the descendants of an earlier migration of H. erectus out of Africa, completely distinct from modern humans and Neanderthals.
[30] Due to the strong divergence in dental anatomy, they may have split before characteristic Neanderthal dentition evolved about 300,000 years ago.
[16] Though their remains have been identified in only these three locations, traces of Denisovan DNA in modern humans suggest they ranged across East Asia,[39][40] and potentially western Eurasia.
By this logic, they may have also entered the Philippines, living alongside H. luzonensis which, if this is the case, may represent the same or a closely related species.
Genetic data suggests Neanderthals were frequently making long crossings between Europe and the Altai Mountains especially towards the date of their extinction.
[11] Denisova Cave, over time of habitation, continually swung from a fairly warm and moderately humid pine and birch forest to tundra or forest-tundra landscape.
[46] This analysis suggested that Denisovans, much like Neanderthals, had a long, broad, and projecting face; large nose; sloping forehead; protruding jaw; elongated and flattened skull; and wide chest and hips.
[47] Middle-to-Late Pleistocene East Asian archaic human skullcaps typically share features with Neanderthals.
A well-developed, Upper Paleolithic stone bladelet technology distinct from the previous scrapers began accumulating in the Main Chamber around 36±4 thousand years ago.
However, Denisovans are only confirmed to have inhabited the cave until 55 ka; the dating of Upper Paleolithic artefacts overlaps with modern human migration into Siberia (though there are no occurrences in the Altai region); and the DNA of the only specimen in the cave dating to the time interval (Denisova 14) is too degraded to confirm species identity, so the attribution of these artefacts is unclear.
[53][10] The inhabitants of Baishiya Karst Cave seem to have been extensively processing goat antelopes, cows, deer, horses, and woolly rhinoceros.
The footprints average 192.3 mm (7.57 in) long, which roughly equates to a 7 or 8 year old child by modern human growth rates.
Comparisons of the Denisovan, Neanderthal, and modern human genomes have revealed evidence of a complex web of interbreeding among these lineages.
[12] About 4% of the Denisovan genome derives from an unidentified archaic hominin,[55] perhaps the source of the anomalous ancient mtDNA, indicating this species diverged from Neanderthals and humans over a million years ago.
[62] A 2011 study found that Denisovan DNA is present at a comparatively high level in Papuans, Aboriginal Australians, Near Oceanians, Polynesians, Fijians, Eastern Indonesians, and Aeta (from the Philippines); but not in East Asians, western Indonesians, Jahai people (from Malaysia), or Onge (from the Andaman Islands).
This may suggest that Denisovan introgression occurred within the Pacific region rather than on the Asian mainland, and that ancestors of the latter groups were not present in Southeast Asia at the time.
[67] The discovery of the 40,000-year-old Chinese modern human Tianyuan Man lacking Denisovan DNA significantly different from the levels in modern-day East Asians discounts the hypothesis that immigrating modern humans simply diluted Denisovan ancestry whereas Melanesians lived in reproductive isolation.
[41] Denisovan genes may have helped early modern humans migrating out of Africa to acclimatize[citation needed].
[72] Denisovan introgressions may have influenced the immune system of present-day Papuans and potentially favoured "variants to immune-related phenotypes" and "adaptation to the local environment".
