The task is not simple. It means sifting the bits of Neanderthal DNA — brittle with age — from 45,000-year-old bones that have been contaminated by bacteria and by the humans who have handled them. The resulting string of genetic information will then be compared with the genomes of humans and chimpanzees. The hope is that the Neanderthal genome will answer basic questions about those hominids that scientists have been unable to resolve using only the fossil evidence. Could Neanderthals talk? Did they interbreed with humans? These are some of the things the genome might reveal.
But the real question to be answered is this: Which genes in our own genome do we share with Neanderthals and which belong uniquely to us? The answers are likely to change the way we think about ourselves as radically as they do the way we think about Neanderthals. Nearly everything we humans have chosen to know about Homo sapiens over time has emphasized how separate we are from the rest of nature. Genetic research has begun to contribute the precise details — part of the broader evolutionary argument advanced by Darwin — that show how surprisingly unseparate we are. The 1 percent genetic difference between us and chimpanzees still feels, to most of us, like a whopping difference. We’ll see how it feels to know our exact relationship to a far closer cousin.