Paabo is also returning to one of his original obsessions. Using a fossil from a site in Croatia, he and his colleagues are trying to derive much longer Neanderthal DNA sequences—not just the DNA that runs the mitochondria, but the DNA that is responsible for building the rest of the body. Their goal is to reconstruct the entire genetic blueprint for making a Neanderthal. It's a technically daunting task, and Paabo estimates it will take about two years to finish. But being able to compare our genome with that of our evolutionary relatives could highlight key turning points in our evolution.
The ultimate goal of his research, Paabo says, is to identify the genetic changes that made us human. Of course, no historical event can ever be reconstructed completely. But by studying our DNA, scientists eventually will be able to say which genes changed, when they changed, and maybe even why they changed. At that point, we'll have something we've never had before: a scientifically plausible and relatively complete story of our biological origins.
About a mile north of the institute, down a dim alley and a flight of stairs, is a very old restaurant known as Auerbach's Cellar. In Johann Wolfgang von Goethe's 1808 epic play "Faust," the devil and Faust go drinking at Auerbach's. Shortly thereafter, Faust meets and talks with two apes—symbols, for Goethe, of human sinfulness and folly.
Faust, of course, sold his soul to the devil for knowledge. Will the knowledge generated by studying our DNA place limits on the human soul? Will people come to see themselves as biological automatons bereft of compassion and morality? Will genetics "biologize" human relationships, so that we begin to define ourselves and others in terms of our DNA sequences?
Paabo worries about such possibilities. DNA studies have revealed how similar we are to other organisms, even such lowly creatures as worms and flies. These discoveries have emphasized the unity of life, Paabo says, but they also have been "a source of humility and a blow to the idea of human uniqueness." Paabo, like most scientists, is an optimist. He believes that genetic knowledge will strengthen our commitments to each other, not rob us of purpose. And studying how we evolved may reveal why human beings suffer from diseases not found in other animals. He is particularly insistent that studies of the evolutionary origins of speech will help children who have congenital speech problems.
But Paabo also says that the possible benefits of research are not his principal motivation. "I'm driven by curiosity," he says, "by asking the questions, where do we come from, and what were the important events in our history that made us who we are. I'm driven by exactly the same thing that makes an archaeologist go to Africa to look for the bones of our ancestors."