In 2015 the genome of Oase-1 was published, a Homo sapiens individual from Romania who lived 38-42 thousand years ago (ka). The study of the genetic material preserved in the mandible showed that this individual had a Neandertal ancestor as recently as four to six generations back. That was shocking…

Now we also have the genome from a long bone of a female human (Denisova 11, aka ‘Denny’) found at the Denisova Cave in Siberia, who was at least 13 years old at death according to its cortical thickness. Direct dating of the fossil showed it to be beyond the radiocarbon limit, hence it is older than 50,000 years, probably around 90-100 ka. Oase-1 now pales in comparison to the findings from Denny…

• Denny’s DNA fragments carried alleles matching in similar proportions the Denisovan genome and the Neandertal genome. She was the daughter of a Neandertal mother and a Denisovan father.

• The Denisovan father had more than one Neandertal ancestor in his genealogy, as recently as 300 to 600 generations back.

• The Neandertals that contributed to the ancestry of the father were from a different population than her mother. The Neandertal mother came from a population more closely related to the Neandertals who live later in Western Europe (compared to the Vindija material from Croatia) than to the earlier Neandertals from the Denisova Cave.

• Eastern Neandertals migrated into Western Europe after 90 ka, and/or Western Neandertals migrated to the Altai region before 90 ka and partially replaced the local population.

(L) Denisova 11, credit Nature vol 560 23 Aug 18. (R) Oase 1, credit Roberto Sáez

The human emotions

When this kind of amazing findings happen, I always try to walk in the shoes of their researches for a moment and imagine their emotion and motivation. For this post, Samantha Brown, one of the authors of the study, has kindly shared with me some of her thoughts:

In 2015 when we first identified the bone (and later published in 2016) it was a shock more than anything. Tom Higham and Katerina Douka had proposed the project to our collaborators and had partnered with Mike Buckley in Manchester who was an expert in ZooMS which was used the method we used to screen the fragments of bone. And while everyone was excited about the prospects of the project it was such an unknown whether anything would ever come of it.

Denny was sample number 1227 out of the 2315 bones we analysed. So it took months to find her from amongst all the fragments and when we did it was like a small miracle had occurred. It completely changed my life and is the reason I’m working on my PhD today.

The collaboration with the genetics team at the MPI for Evolutionary Anthropology has been an absolute dream. They are the best at what they do. In fact, they managed to get the mitochondrial DNA results to us the day before I had to submit my Masters thesis so I could include it. The new paper released on Wednesday is really a tribute to their amazing work. They spent months making sure their conclusions were correct and ruling out any other possibilities.

Who would’ve thought that tiny fragment of bone would become so important!

As Tom Higham tweetted, Samantha Brown made the name ‘Denny’ up in 2015, and the team was joking using it all the time in the lab. Then it became Denisova 11 after it was published in 2016, and now the alias Denny is back!

I also recommend the blog post that Viviane Slon has put together, addressing the behind the scenes work that went into the Project.

Hominin interbreeding. Credit: AFP, Nature/National Geographic

Now what?

The overall knowledge to date shows that mixing among archaic and modern hominin groups may have been frequent when they met:

• A first-generation Neandertal–Denisovan offspring has been found in a still sparse fossil record, and among the small number of ancient human DNA samples sequenced to date.

• One modern human with a close Neandertal relative (Oase 1) is also included in that selected group of few individuals with preserved and retrieved DNA, and who lived at the time of overlap of these groups.

• The presence of Neandertal and Denisovan DNA is also well-demonstrated in ancient and present-day people.

Therefore, we can expect more shocking finds like this one in the next few years. I would bet that some researches are already working on it. Paleogenetics has dramatically changed the way we understand Paleoanthropology.
Further information:

• The genome of the offspring of a Neanderthal mother and a Denisovan father | Nature [link].
• A new Denisovan! | Nutcracker Man [link].
• ¿Quiénes son los denisovanos? (en español) | Nutcracker Man [link].