Meet Our Newest Relative

Our newest relatives hailed from around this cave in Siberia.

In 2008, scientists found a fossil of a humanoid finger in the Denisova Cave in Siberia. The finger was probably from someone (or something) that had been running around Siberia forty thousand years ago.

Until recently, the scientists would have been stuck until they found additional fossils to build up a more complete skeleton. Once they had the skeleton, they could then compare it to other fossils and figure out how it related to modern humans. Of course this might never happen—it would be totally dependent on finding more fossils.

Rather than waiting around, these scientists decided to bring in a geneticist. Nowadays geneticists can sometimes read every base of a fossilized beast’s DNA. In other words, they can read its whole genome.

When geneticists did this, they found that the finger did not come from a modern human or a Neanderthal. This Denisovan (as scientists named it) probably came from a previously unknown relative that was more closely related to Neanderthals than humans. And surprisingly, their legacy lives on in some modern humans.

By comparing the DNA of the Denisovan and various modern ethnic groups, scientists could see Denisovan DNA in modern Melanesians. Apparently the ancestors of Melanesians and Denisovans had babies before the Denisovans went extinct.

The data suggest that Denisovans might have contributed up to 4-5% of their DNA to modern Melanesians. Add the 1-2% Neanderthal DNA found in non-Africans and you get up to 7% of Melanesian DNA coming from nonhuman sources. And that is just based on the two extinct species whose DNA we’ve been able to read so far.

Who knows how much DNA of other ethnic groups comes from relatives whose DNA we haven’t looked at yet. I bet someone is taking a good hard look at various groups’ DNA to see if they can answer this question without having to figure out more fossil DNA.

This all points to an exciting new twist to paleontology…the ability to look at DNA from fossils and to compare that DNA to modern humans and any other close relatives whose DNA has been sequenced. This new avenue of research should provide extra information that scientists didn’t have before and allow them to figure some things out with just a single finger bone.

BBC story on the find.

37.7749295 -122.4194155