Chimpanzees may be more closely related to humans than to any other primate, new genetic evidence suggests.
"We all know that humans and chimps are extremely close genetically," says study coauthor Soojin Yi, an evolutionary biologist at the Georgia Institute of Technology in Atlanta. The two species diverged from a common ancestor from 5 million to 7 million years ago and have 95 to 98 percent of their DNA in common, previous research has established.
But by measuring the accumulation of small differences in DNA between the two species, Yi and her colleagues found another shared trait: a slow "molecular clock," or rate of evolutionary change.
Of all primates, modern people live longest, have the longest gestation time, and reach sexual maturity latest, Yi says. More time between generations means slower rates of evolution at the level of DNA, or a slower molecular clock, she says.
But chimp clocks don't tick much faster, the new study shows. After analyzing