Benvinguts a Barcelona: Part 3 of 3

Last month I had the opportunity to go to the Society of Molecular Biology and Evolution conference in the striking city of Barcelona. This is the premiere conference for geneticists studying evolution in everything from bacteria to fruit flies, weeds, worms and our favorite model organism, humans! This is a highly interactive conference: almost everyone attending presents his/her own research, us included. This series describes some of the highlights from the conference.

Neanderthal and Homo sapiens skeletons side by side. The thicker femurs, different eye sockets and barrel-shaped chest of our distant relatives are prominent in this comparison.

Mining the past: The Neanderthal Genome Project
The first invited speaker at the SMBE 2008 conference was Svante Pääbo of the Max Planck Institute for Anthropology in Germany. Pääbo and colleagues continue their incredible project to sequence the Neanderthal genome. Neanderthals are especially interesting in understanding our own history; they were another animal that walked upright, hunted with weapons, used clothes, and had culture, traits we consider very “human.” Pääbo presented some new findings that may change the way we think about our own history and that of our distant cousins, who went extinct around 25,000 years ago.

So far, the project has sequenced more than 3 billion Neanderthal DNA base pairs. The figure sounds impressive, and it is. However, sequencing ancient DNA is subject to contamination and in fact more than 99% of the DNA Paabo’s group extracts from Neanderthal bones is from bacteria, fungi or other organisms — including modern humans.

Scientists have debated for decades whether Neanderthals and humans interbred. So far, the Neanderthal genome does not show any evidence of having human ancestry (Ed: see this blog post for more recent research on the subject). But the recent split between humans and Neanderthals has resulted in some sharing of genetic material between the species. That is, some people may share versions of SNPs with Neanderthals, but this sharing traces to a common ancestor who lived before the two species split about 800,000 years ago.

One especially interesting finding by Paabo’s group was in the so-called “language gene,” FOXP2. Humans have a very different version of FOXP2 than most other mammals, birds, and reptiles. Rare deletions in the gene cause people to have trouble with speaking and comprehension, providing support that the gene is important for language. Interestingly, other verbal mammals also have changes in FOXP2.
Scientists had thought the “human” version of FOXP2 arose within the last 200,000 years, since the origin of Homo sapiens and long after the human lineage split from Neanderthals. However, it turns out Neanderthals share the human version of FOXP2. These results indicate that something else happened in human history to make FOXP2 appear younger than it really is; and that this may not be related to the unique version of the gene shared by humans and Neanderthals.
So, is FOXP2 the gene that makes us unique from other animals? No. But could it still have played an important part in our own history? Probably. Just one of the many mysteries that evolutionary geneticists hope to answer.