Then, in October 2007, Pääbo and coworkers published a jaw-dropping paper about FOXP2 in Neanderthals, evolutionary relatives of modern humans that died out 30,000 years ago. The researchers isolated parts of the FOXP2 gene from the bones of two Neanderthals. Although they have yet to sequence the entire gene, they found that Neanderthals and modern humans matched at the two critical spots that separate humans and chimpanzees. Though often depicted as knuckleheads, our closest hominid relatives may have shared at least some of our capacity for speech and language. “There is no reason to think that Neanderthals did not have language as we do,” says Pääbo. But he adds that the many unknown genes involved in language will eventually have to be found and looked at in Neanderthals.
Geschwind is continuing his hunt for those unknown genes, applying to his behavioral-genetics work the technique he developed to compare human and chimp gene expression. His lab is now doing the same sort of coexpression studies on brains from healthy humans and schizophrenics, which he hopes will uncover connections that are broken in schizophrenia and perhaps lead to still more genetic pathways related to speech and language. He hopes eventually to do similar analyses with autopsied brains from people who had autism-spectrum disorders.
So far, Geschwind and his colleagues have found what amount to some interesting genetic words that they’ve been able to string into a few sentences to explain the roots of speech and language. They can’t yet tell a coherent story. Still, confidence is building that in the not-too-distant future, scientists will be able to write a lengthy book about how we evolved our phenomenal gift of gab, highlighting the critical suites of genes that make it possible. If they do, they could also find ways to correct disruptions to this network–disruptions that can leave people at a serious loss for words.