Did humans and Neanderthals ever lie under the moon, making love? Could Neanderthals talk? Do we have any of their genes? We diverged from our hominid cousins as long as 400,000 years ago, and by 30,000 years ago they were gone, leaving the particulars of any intertwined history seemingly lost forever.
We are beginning to revisit those ancient days, however, due to a draft of the Neanderthal genome created by Svante Pääbo and colleagues at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. The draft, announced in February, covers about 63 percent of the roughly 3.2 billion base pairs in the Neanderthal genome. Pääbo created it by sequencing DNA from fragments of bone (most of it from the Vindija cave in Croatia) to get 3 billion Neanderthal base pairs essentially uncontaminated by human DNA or by microbes.
To perform this stunning feat, Pääbo and his team used new, high-throughput DNA technologies—developed in part by the companies 454 Life Sciences and Illumina—to analyze hundreds of thousands and even millions of DNA fragments at the same time.
With the ability to sequence DNA at warp speed, the re-searchers could finally deconstruct the genomic relationship between Neanderthals and modern humans. Although our DNA sequences are more than 99.5 percent identical, our genetic cousins did not contribute any mitochondrial DNA to us, and probably little genetic material overall. (It is still possible that we donated genes to them, however.) “We are now analyzing whether there was any interbreeding” at all, Pääbo says.
In studying the reconstructed genome, he learned that, like modern humans, Neanderthals may have used the spoken word. Indeed, they have two mutations in a language-associated gene called FOXP2, mutations that are not found in chimpanzees. Such changes seem to be associated with vocalization. “From the data we have so far, there is no reason to assume that Neanderthals could not speak like we do,” Pääbo concludes.
What lies ahead? Pääbo will continue sequencing Neanderthal DNA until he has a genome that is similar in completion and quality to the existing map of the chimpanzee genome. Ultimately, comparing Neanderthals, humans, and chimpanzees will help us find “those few genetic changes that are crucial for modern human behavior and ability,” he says, and that reveal what makes us uniquely human.