THE EARTH was a more crowded place than we realised in the days of the caveman.
Scientists have discovered a new kind of early human who lived alongside Neanderthals and modern humans 40,000 years ago.
Remarkably, the previously unknown “hominin” – or extinct human ancestor – was identified after researchers successfully collected the creature’s DNA from a broken bit of a finger bone found in a cave in Siberia.
This is the first time that a hominin has been proven to be unique using its DNA alone rather than by studying a collection of fossilised bones.
The unnamed hominin really was a caveman, or at least a bit of his finger ended up in a cave, the Denisova Cave in the Altai Mountains of southern Siberia. This opening in the side of a mountain shows signs of intermittent human occupation as far back as 125,000 years ago.
The finger bone was located in a cave soil layer dated to between 48,000 and 30,000 years ago so the research team from the Max Planck Institute in Leipzig and the University of Manchester have sound information that the Siberian was not alone.
Neanderthals and modern humans were also known to have occupied the region during the same period.
Nor is there any confusion over the Siberian’s lineage and kinship. Its DNA is unique, so both Neanderthals and modern humans would have failed that particular paternity test.
The authors, who published their findings yesterday evening in the online version of the journal Nature, are equally excited about what the Siberian’s DNA tells them about early human migration.
The DNA shows that the Siberian hominin is clearly a different species, but all three species shared a common ancestor.
This common progenitor lived a million years ago, most likely in Africa, the DNA showed.
So the only conclusion is that each of the three species underwent its own migration out of Africa, the authors argue.
“This indicates that it derives from a hominin migration out of Africa distinct from that of the ancestors of Neanderthals and of modern humans,” they write.
The research also shows that our modern human forebears are likely to have encountered a “crowd of ancestors” as they migrated into Eurasia, according to an accompanying news and views article in Nature.
There were members of our own species and also the Neanderthals.
These are now joined by the Siberian and its people, and if this hominin strayed much further east it might have encountered another recent addition, the diminutive “hobbit” people whose bones were discovered on the Indonesian island of Flores.
The question is, how many more similar finds are there likely to be, given the power of modern DNA analysis?