New Ideas

“It is striking that we find this Denisovan/Neanderthal child among the handful of ancient individuals whose genomes have been sequenced,” the Max Planck Institute’s Svante Pääbo told the Evening Standard. “Neanderthals and Denisovans may not have had many opportunities to meet. But when they did, they must have mated frequently – much more so than we previously thought.”

Adjusting Our Historical Views

Although it’s possible that the discovery was little more than a lucky break, researchers are considering other explanations. One of these is that the two species of hominin actually interacted – and interbred – with each other on a regular basis. And if this theory is true, it would turn our previous understanding of the ancient world on its head.

Denny Bone

But the bone of the teenager – who has been dubbed Denny – isn’t the only evidence that lends support to this hypothesis. Up to 2018, scientists had only conducted genetic research on a relatively small number of ancient humans – 23, to be precise. Still, even within this tiny sample, there were at least two specimens that showed evidence of interbreeding between species.

Mixed DNA

Take the individual known as Oase 1, for instance. Identified by their lower jaw, this member of Homo sapiens is believed to have walked the planet about 37,000 years ago. But despite their relatively recent place on the human family tree, they were found to be carrying Neanderthal DNA.

Few And Far Between

And we’re not talking about the very distant past, either. According to a report published in the journal Nature in 2015, Oase 1’s Neanderthal forebears may have been alive only four to six generations previously. If interbreeding between species had only occurred sporadically, Pääbo reasoned, discoveries such as this should be few and far between.

Mixing Freely

On top of that, the study from the Max Planck Institute noticed something else about Denny. Apparently, the teenager’s father also had Neanderthal DNA combined with his Denisovan genes. And that’s incredibly revealing. According to Pääbo, “It suggests that these groups, when they met, mixed quite freely with each other.”

Transformed Understanding

Previously, most researchers assumed that interactions between these different groups had happened only infrequently. So, how do these latest developments alter our view of ancient humans and their evolving society? Speaking to National Geographic, Reich explained, “[It]... qualitatively transforms and changes our understanding of the world. And that’s really exciting.”

Pleistocene Eurasia

Of course, there could be other explanations as to why a first-generation hybrid has already appeared in such a limited sample size. In Green’s opinion, caves such as the one in the Altai Mountains could simply have been popular meeting points for ancient humans, bringing sampling bias into the equation. Or, as the specialist neatly put it in an interview with National Geographic, “They’re the singles bars of the Pleistocene Eurasia.”

Key To Survival

But was it simply proximity that inspired the Denisovans and the Neanderthals to interbreed? Or was something else at play? Well, according to the University of Tübingen’s Katerina Harvati-Papatheodorou, such cross-species interactions could have formed a vital part of survival. Speaking to New Scientist, the German academic explained, “Human groups were very small and vulnerable to drastic mortality.”

Died Out Or Assimilated

And as more information emerges, scientists hope to solve some of the mysteries that have long puzzled those who study human evolution. Did the Denisovans and Neanderthals quickly die out as Homo sapiens began to thrive? Or were they simply assimilated into the dominant species? In an interview with New Scientist, Princeton University’s Joshua Akey admitted that Denny’s DNA points to the second of those assumptions, although we are a long way from a definitive answer.