Introducing Denny: Offspring of a Neanderthal Mother & Denisovan Father

In 2008 the paleoanthropological community was rocked by the announcement of a new hominid discovery.  While this may not seem like that great of news, particularly as the discovery of new hominid species has become commonplace, this particular discovery was groundbreaking because the identification of this species was based on paleo-DNA collected from a tooth and finger bone.  Further analysis demonstrated that the newly discovered species, named after its place of discovery, the Denisovans, interbred with anatomically modern humans throughout Eastern Asia, which was evidenced by the presence of their DNA within those populations.  Since that initial 2008 discovery further study into Denisovans has been done, but unfortunately very few physical pieces of evidence (i.e. anatomically remains) have been discovered.  This makes further study difficult but not impossible.  With the advances in paleo-DNA methods a new Denisovan related discovery has been made-that of Denny, the 13 year old daughter of a Neanderthal mother and Denisovan father. 

Denny was an accidental discovery by several different researchers associated with the Max Plank Institute, where the original investigators who discovered Denisovans are based.  A cache of bones were being studied as part of a Masters thesis when a set of mysterious, human-like bones were identified (pictured above).  The bones looked morphologically similar to anatomically  modern humans but were also similar to other species, and it was again paleo-DNA that positively identified this specimen as human…ish.  The DNA signature was similar to Denisovans but not identical. 

Paleogeneticists Viviane Slon and Svante Pääbo took custody of the remains at this point and conducted more analyses, which they published prelimary results on in 2006.  Further research demonstrated that the species was one born from an expected but not yet discovered union-that of a Neanderthal and Denisovan union.  When the results were first brought to Slon’s and Pääbo’s attention they did not think it was possible, leading them to conduct additional analyses to confirm and reconfirm their initial findings.  It was from here that a more robust picture of the specimen was fleshed out.

The bone specimens belong to a 13 year old female who lived approximately 90,000 years ago, who has been nicknamed Denny.  While there is evidence that Neanderthals were living at the same site as Denny none of these Neanderthals were her mother.  Instead her mother most closely resembles Neanderthals who resided in Western Eurasia, specifically in Croatia.  This suggests that Neanderthals were migrating into Asia, although not en masse.  Furthermore, the Denisovan father had at least one Neanderthal relative in his lineage, spanning several generations previous. 

Taken together this evidence demonstrates that Neanderthals and Denisovans were interbreeding, although the extent is considered small since both species remained genetically distinct for several hundred thousand years.  This has led researchers to hypothesize that Neanderthal-Denisovan offspring were infertile (not as likely given the lineage of the Denisovan father) or that Neanderthals and Denisovans did not interact as much given their geographic separation.  The majority of Neanderthal specimens have and continue to be found throughout western Eurasia, while Denisovans have been found on the eastern side of the continent, still largely in the Denisova Caves in Siberia.  Therefore it is most likely that geographical separation led to genetic separation, as well, hence why Denny is the first Neanderthal-Denisovan offspring to be found.

While the first and only one discovered thus far Denny provides scholars a great deal of insights into our human origins.  While we already knew that Neanderthals and Denisovans were breeding with anatomically modern Homo sapiens the discovery of Denny further blurs the lines of what is considered biological human within our hominid ancestry.  She suggests that instead of distinct, genetically isolated species that at least among the three species they were genetically similar, which may not warrant specific species classifications that currently exist.  This means instead of recognizing Neanderthals as Homo neanderthalensis we might be changing it to Homo sapiens neanderthalensis to acknowledge they and Denisovans (who have not yet been given a formal species name) were just as human as the rest of us existing today.

References

Choi, C. Q. (2018, August 22). Neanderthals and Denisovans Mated, New Hybrid Bone Reveals. Retrieved from Live Science: https://www.livescience.com/63400-neanderthals-denisovans-mated-leg-bone.html

McKie, R. (2018, November 24). Meet Denny, the ancient mixed-heritage mystery girl . Retrieved from The Guardian: https://www.theguardian.com/science/2018/nov/24/denisovan-neanderthal-hybrid-denny-dna-finder-project

Scharping, N. (2018, August 22). Hybrid Hominin: This Girl’s Mother and Father Came From Two Different Species. Retrieved from Discover Magazine: http://blogs.discovermagazine.com/d-brief/2018/08/22/neanderthal-denisovan-interbreeding-hybrid-species/#.XREX8CB7mUk

Warren, M. (2018, August 22). Mum’s a Neanderthal, Dad’s a Denisovan: First discovery of an ancient-human hybrid. Retrieved from Nature: https://www.nature.com/articles/d41586-018-06004-0