Neanderthal expert weighs in on ancient ancestors

Last Tuesday one of the world's leading experts on Neanderthals, Jean-Jacques Hublin, spoke at the Houston Museum of Natural Science. The founder and director of the Department of Human Evolution at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, Hublin also spoke with Chronicle science writer Eric Berger about the latest research into the closest ancestor of modern humans, who died out about 30,000 years ago.

Q. We've learned a lot about Neanderthals in the last decade, like how some bred with humans, and we've also begun to look at their genetics. How has the field progressed?

A. First of all, it's because of the wealth of material that's been unearthed, both in Europe but also in the Near East and Central Asia and now in Southern Siberia. It's probably now the best documented fossil group of hominins. There are also new techniques now to study fossils. And of course there is genetics. For the first time it is now possible to have the genome for an extinct group of hominins.

Q. What have we learned about the Neanderthals from genetics?

A. Having the sequencing of both the Neanderthal and the Denisovan, who were a closely related sister group to the Neanderthals, gives us not just an understanding of who were the Neanderthals, and what kind of creatures they were, but also an understanding of what the modern humans are. That is because until now it was possible only to compare the genome of humans with chimpanzees that got separated from us 6 or 7 million years ago. So we could only say that all the changes that we saw in the human genome, that changes that differentiated humans from apes, had occurred in the last 6 million years. Now it's possible to know what happened in the last 300,000 or 400,000 years when humans and Neanderthals diverged. This completely changes the picture.

Q. How so?

A. One thing that happened with modern humans is that they replaced totally all the other hominins on Earth. This is the first time that happened in the course of human evolution, that one species had such a development. And so there is something very special about modern humans that we would like to understand. So our work with understanding Neanderthals is also helping us understand what makes humans so special.

Q. What do the differences in human and Neanderthal genomes tell us about the Neanderthals themselves?

A. There are two things. One is demography. We're going to have a much better picture of the growth and decrease in size of these populations. How many Neanderthals lived? Already for the Denisovans, it has been shown that their numbers were very low compared to modern humans, and that they accordingly had a low diversity in their population. The second thing that paleontology cannot teach us is much about biology. Basically the take-home message is, it's not enough to have a big brain, it's important how the brain is wired, and this wiring has been changing a lot in the recent evolution of humans. It's tempting to relate that to the technology and social networking differences between humans and Neanderthals.

Q. What were the networking differences?

A. The picture we have so far is that the Neanderthals are sort of opportunistic, good at hunting middle- to large-sized mammals. They have a territory in which they probably go through a cycle of habitation in different places, basically when one place is exhausted they move to another one. What we don't see with Neanderthals is long-distance exchanges with other groups. What we see with modern humans in the same areas is different. For example, we find shells in Germany coming from the Mediterranean or from the French Atlantic Coast. It means there was a network of people. So, the question is, what kind of relationship did a Neanderthal have with his brother-in-law? Humans did not just live with their families and their neighbors, but they knew they had a brother-in-law in another village, and that beyond the mountain there is the family of their mother, or uncle, or something like that. There is a large network of groups that, if necessary, could help each other. I think this is where we would like to go to find differences between Neanderthals and modern humans.

eric.berger@chron.com