Chimpanzees are so closely related to humans that they should be considered part of the human family. Genetic researchers examined key genes in humans and several ape species and found our “life code” to be 99.4% the same as chimps. They think we should move chimps and their close cousins the bonobos into the genus Homo, along with us.So far only humans (and extinct Neanderthals) are classified in that group.

“Since people have been studying primate evolution, there’s been this dichotomy between humans and the apes, says researcher Derek Wildman. “And so what we’ve shown is that humans and chimpanzees are actually more similar to each other than either is to any of the other apes.” Before the discovery of DNA, different species were identified on the basis of how they looked, either alive or as fossils.

The researchers compared 97 major genes from humans, chimpanzees, gorillas, orangutans, Old World monkeys, and mice, and measured their degree of relatedness. They found that chimpanzees and humans should be side by side on the same family tree. On lower rungs are gorillas, then orangutans, followed by Old World monkeys. None of the primates were closely related to mice, which were used as a control.

“You could say that humans and chimps are as similar to one another as say horses and donkeys,” Wildman says. “?There has been this notion since Aristotle’s time of this great chain of being with humans at the top and then less complex life at the bottom. But while that might seem intuitive to some people, it doesn’t appear to be borne out by the data.”

Other researchers comparing human and chimp DNA have found the similarity closer to 95%. The figure you get depends on which genetic differences you look at. Wildman says, “There’s been as much change on the lineage on the line leading to chimpanzees as there has been on the lineage to humans since they last shared a common ancestor around six million years ago.”

If you have questions about the ancient origins of mankind, William Henry has some fascinating answers for you.

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