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When researchers discovered a fossil finger in a Siberian cave, they found an ancestor - and perhaps a new human species. Johannes Krause told Deutsche Welle about his team's efforts to analyze the ancient DNA.
Scientists analyzed DNA from a fossil finger found in Siberia
The new report was published on the website of science journal "Nature" on March 24. Leipzig researchers Johannes Krause and Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology co-authored the international project.
Deutsche Welle: How did you find a bone fragment from the Altai Mountains?
Johannes Krause: For several years, we've been involved in a very productive collaboration with our colleagues in Russia. We received bones from them that we later identified as Neanderthal bones, for example, thus showing that Neanderthals lived in southern Siberia, too - not just in Europe. And in recent years, we've received other bone samples for genetic testing. Here in Leipzig, we've taken our Neanderthal research to the genetic level, so we've been examining the DNA of ancient man (...) to help us learn how prehistoric man is related to modern-day man or other forms of early man. The Neaderthal has their own DNA at least for portions of the genome, so they aren't our direct ancestors; they're more an extinct cousin of sorts.
DNA analysis of homonid species could shed light on their ties to modern man
And during our search for new Neanderthal bones, we stumbled upon these bones with DNA that belonged neither to Neanderthals nor modern man. It constitutes a new form of prehistoric man that had never been discovered - something we had never seen from a genetic standpoint and that we couldn't categorize as an existing form of prehistoric man.
Everyone's calling this a sensation - would you call it that?
I think it's a sensation because until now we had the potential to do genetic research on two different forms of man - now there's a third. So that's pretty sensational, particularly as it can't be classified according to any existing form of prehistoric man. Unfortunately, we don't have a complete skeleton - just the bone from a pinkie finger. It's a tiny fragment that can't tell us much about the morphology. Therefore we still don't know what this prehistoric man looked like - did he perhaps look like a Neanderthal, modern man or a Homo erectus?
So we lack quite a lot of information, but we now have the potential to study the DNA of this prehistoric man; we have the potential to examine the entire genome and genetic material from this prehistoric man and compare it to modern man and the Neanderthals, for instance. And through that, we can learn a lot. For example, what kind of interactions occurred between these three species of prehistoric man? We could also show that they lived in the same place at the same time - that's another sensation for us. That means, we find Neanderthal bones in a nearby cave, and in same layer in which we found the bones of the new human form, we find archaeological artifacts that appear to have come from modern man - ornaments and jewelry that are only associated with modern man. So it looks as though these three forms of early man lived in the same place at the same time. You can then imagine any number of scenarios where gene flow could have occurred between these three populations, and that is certainly something that's very interesting to analyze on a genetic level.
Is finding something like this an anthropologist's dream come true?
Russian researchers discovered the fossil bone at a site in the Altai Mountains in Siberia
Yes, this is probably a once-in-a-lifetime chance - discovering a new species or form of prehistoric man. It's certainly quite exciting for us. Of course, we should note that we're not calling it a new species - we're only talking about a new "form." So far, we've only analyzed a tiny portion of the DNA, and only when the entire genome or a large part of the genome has been analyzed will we be able to tell whether it's something completely new or different, like modern man or the Neanderthals, for instance. And until then, we're not going to talk about a new species. But all signs indicate that we're actually dealing with an entirely knew species of man here.
Then what do you know already; whose bones are they?
So far, we can only say that this DNA - the DNA we've studied so far from this prehistoric man - has about 1 million years between it and the DNA of modern man. So that means that these two forms, modern man and prehistoric man, spent at least 1 million years developing in very different ways. Based on our genetic tests, we can also say that modern man is more closely related to the Neanderthals than he is to this new form of prehistoric man - we're seeing two times as many differences between the DNA of modern man and this new form than we do with modern man and the Neanderthals. This represents a completely different line that split off from modern man much earlier.
Mitochondrial DNA decoding showed differences between the ancestor and modern man
Do you know if it was a woman or a man?
We've named it "X Woman." "X" stands for the unknown, since we can't classify it so easiliy, as I'd mentioned. And "Woman" because we examined the mitochondrial DNA - the DNA from the powerhouse of the cell - and that's always passed down from the mother to the child. So we're looking at the female lineage, and so we adopted a feministic position. But since we have yet to examine the entire genetic material, we still don't know whether it's a man or a woman.
And this process for examining the mitochrondrial DNA - that's something you developed?
Yes, my boss Svante Pääbo studied mitochrondrial DNA from prehistoric man for the first time in the '90s - at the time, from Neanderthals. In recent years, we have refined these methods to help us obtain more information more quickly -- and of a higher qualitative value. But we've really kicked this kind of research into high gear in recent years.
What's next? What else do you plan to study - and what do you hope to find?
We plan to study the entire genome - this prehistoric man's entire genetic material.
We don't just want to look at this tiny fraction, rather we will examine the entire genome to learn more about this prehistoric man and to see how he was related to modern man and to Neanderthals.
The Neanderthals share many commonalities with modern man
Was there potential gene flow between these three populations? And what can we learn about phenotypical features - what color hair did he have? We'll look at other kinds of features that we can reconstruct based on DNA sequencing.
And who gets to keep the bone once you conclude your research?
Whatever's left of the bone will certainly be sent back to Novosibirsk, to the museum responsible for the entire excavation. That said, it's not a spectacular bone - it's only as large as cherry pit. So it's a very tiny fragment and it might not be all that interesting to look at.
Interview: Andreas Ziemons (arp)
Editor: Anke Rasper