A new study looks at what Denisovan ancient DNA codes for in order to determine which hominin remains that have been located are the best fit to that DNA. These remains would have been contemporaneous with the earliest modern humans and with Neanderthals.
The Dali and Harbin specimens that are a good fit to the expectation from the Denisovan DNA samples are from China.
Dali Man was discovered in 1978 in Dali County, Shaanxi Province, China and dates to 280,000 to 240,000 years ago.
The Harbin specimen was recovered in Harbin city in northeastern China and has a minimum uranium-series age of 146,000 year ago.
The Kabwe specimen, also known as the "Broken Hill skull" and "Rhodesian Man", which is also a good fit to Denisovan DNA expectations, was discovered in 1921 in Zambia, which is outside the range of places where Denisovan admixture is found in modern humans. It has traditionally been classified as Homo heidelbergensis, a species which is widely hypothesized to be a lineage ancestral to Denisovans, Neanderthals, and modern humans. This specimen is dated to 324,000 to 274,000 years ago.
Denisovans are an extinct group of humans whose morphology is mostly unknown. The scarcity of verified Denisovan fossils makes it challenging to study how they differed in their anatomy, and how well they were adapted to their environment. To gain insight into their evolutionary history, we used a genetic phenotyping approach, where Denisovan anatomy was inferred by detecting gene regulatory changes that likely altered Denisovan skeletal morphology.
We then scanned Middle Pleistocene skulls for unclassified specimens that match our Denisovan profile and thus might have been related to Denisovans. We found that the Harbin, Dali, and Kabwe specimens show a particularly good match to the predicted Denisovan profile. We conclude that our genetic phenotyping approach could help classify unidentified specimens, and that Harbin, Dali, and Kabwe likely belonged to individuals closely linked to the Denisovan lineage.
Nadav Mishol, et al., "Candidate Denisovan fossils identified through gene regulatory phenotyping" bioRxiv (April 19, 2024) (emphasis and links in the abstract added editorially).
Dali man (Chinese: 大荔人) is the remains of a late Homo erectus or archaic Homo sapiens who lived in the late-mid Pleistocene epoch. The remains comprise a complete fossilized skull, which was discovered by Liu Shuntang in 1978 in Dali County, Shaanxi Province, China.
ReplyDeleteCommon name Dali Skull
Species late Homo erectus, Homo heidelbergensis, or archaic Homo sapiens
late Homo erectus in Asia was trending to archaic Homo sapiens which is what multi regional theory predicts
@neo Genetic data doesn't support that conclusion.
ReplyDeletehow do you explain the fossil evidence that shows late Homo erectus in Asia overlap with archaic Homo sapiens?
ReplyDeleteDid they compare specimens from small islands in Indonesia? I can't recall details, will look around for some info.
ReplyDelete@DDeden , no, they eliminated them from consideration:
ReplyDelete"We acknowledge that H. floresiensis and H. luzonensis share temporal and geographic overlap with the test subjects. However, they were not included in this study because they were absenct from the Morphobank dataset. Despite inhabiting Southeast Asia, their overall morphology and smaller dimensions strongly suggest that they represent distinct hominin lineages, differing significantly in anatomy from Denisovans. Similarly, we did not include H. naledi specimens in this study due to their distinct morphology, particularly their brain size, which likely places them on a separate hominin lineage from Denisovans"
which is honestly fair enough, since the traits they derived were quite the opposite from these small species, but that of a robust, heidelbergensis-like species, so there's little chance those would fit anyhow. Note they classify one skull typically classified as heidelbergensis among the 3 closest matches, and they don't seem to think this is real:
"The resemblance of the Denisovan profile to several H. heidelbergensis specimens, and specifically the African specimen from Kabwe, is particularly intriguing. Despite our limited understanding of the true range of Denisovans, it is unlikely that they reached Southern Africa. A more likely explanation is that the resemblance of some H. heidelbergensis specimens to the Denisovan profile reflects the proposed phylogenetic position of H. heidelbergensis either close to the split between modern humans and archaic humans or close to that between Neanderthals and Denisovans. If H. heidelbergensis is indeed phylogenetically close to the Neanderthal-Denisovan divergence, it is expected to exhibit even greater similarity to the Denisovan profile than the similarly of Neanderthals to the profile. An alternative explanation is that Denisovans possibly retained several ancestral morphologies observed in H. heidelbergensis"
Note that Dali too is traditionally described either as a heidelbergensis (H. heidelbergensis daliensis) or as something else in between late erectus and archaic sapiens (i.e. also "close to the split between modern humans and archaic humans"), and it clusters morphologically closest with both Harbin and Xiahe mandible (that has some independent proteomic evidence for being Denisovan) in the Harbin paper as well, so I'm not sure what's surprising in finding it closely associated in this paper as well.
ReplyDelete