Rebecca Wragg Sykes
Archaeologist based at the Université de Bordeaux
“It’s hard to overstate the importance of finding Denny. A decade ago we had no clue that her father’s people even existed, much less that children like her existed. In May 2010 the first Neanderthal genome was published, proving that rather than usurping them, early Homo
sapiens made babies with them. But just the month before, samples from a tiny finger bone in Denisova Cave, Siberia revealed an entirely new hominin species.
“Now known as D3, this bone was at least 10,000 years younger than Denny. Thanks to ancient DNA, today we’ve identified five Denisovans. But we know more about their history as a species than we do about their technology or even their appearance. Some of them had genes for dark hair, skin and eyes, but how tall they were or what their faces were like are mysteries.
“Despite all samples so far coming from one site, they were far from isolated. Both they and Neanderthals bred with H. sapiens, but in different times and places. Asians and native Americans have more Neanderthal DNA than Europeans, which might reflect more interaction in that region, or elsewhere in a group which later moved eastwards. Denisovan blood is even more unevenly distributed: living populations of Oceania and Australia have up to 25 times more than anywhere else. It’s clear we’re seeing only a fraction of the true picture.
“Neanderthals and Denisovans weren’t shy of each other, either. D3’s genes showed interbreeding tens of thousands of years before she died. Denny’s father’s forebears were also making babies with Neanderthals up to 17,000 years earlier. Intriguingly, those far-off encounters were with a Neanderthal lineage different from that of Denny’s mother.
“Finding the child of a Neanderthal and a Denisovan should make us sit up and think. Until now, most evidence has pointed to small, localised populations in both species. Added to this, studies mapping the distances that stone tools were moved from their source pointed to relatively limited territories. On this basis, dominant theories emphasised Neanderthals as socially ‘exclusive’: avoiding outsiders, limited to topographic, cultural and genetic valleys. If that’s true, it’s unlikely we would ever find the result of such an encounter, so Denny is telling us something about these models is wrong.
“Populations were likely small, so the startling fact of Denny’s parentage means the other part of the equation must be wrong: Denisovans and Neanderthals must have been quite keen on strangers. But how did populations who were happy to blend stay so distinct genetically? One theory is that mixed children had a tougher time reproducing, but we just don’t know yet.
“Why does this matter? One of the most influential ideas about why the Neanderthals disappeared is that
H. sapiens had more extensive territories – if we map the distances stone tools were carried, early H. sapiens come out ahead. But finding Denny strongly suggests stone tool mobility can’t be a real measure of sociability. Another extinction theory may soon bite the dust.”