(Picture is of "Clint," the chimp whose DNA was unraveled.)
Scientists have deciphered the DNA of the chimpanzee, the closest living relative of humankind, and made comprehensive comparisons with the human genetic blueprint. It's a step toward finding a biological answer to a key question: What makes us human?
There are no firm answers yet about how humans picked up key traits such as walking upright and developing complex language. But the work has produced a long list of DNA differences with the chimp and some hints about which ones might be crucial.
"We've got the catalog, now we just have to figure it out," said Dr. Robert Waterston of the University of Washington School of Medicine in Seattle. "It's not going to be one gene. It's going to be an accumulation of changes."