With the advent of molecular techniques to compare similarities in our DNA starting in the 1960s, most experts have come to accept the fact that humans and chimps are most closely related. Studies indicate that humans and chimps are between
95 and 98.5 percent genetically identical.
Derek E. Wildman, Goodman, and other co-authors at Wayne State argue in their new study, published today in the journal Proceedings of the National Academy of Sciences, that given the evidence,
it's somewhat surprising that humans and chimps are still classified into different genera. Other mammalian genera often contain groups of species that diverged much earlier than chimps and humans did, said Goodman. "To be consistent, we need to revise our definition of the human branch of the tree of life," he said.
Goodman and colleagues used computer methods to analyze the amount of similarity between 97 important human and chimp genes and as many of the same gene sequences as are currently available for less-studied gorillas, orangutans, and Old World monkeys.
The results suggested that within important sequence stretches of these functionally significant genes,
humans and chimps share 99.4 percent identity. Some previous DNA work remains controversial. It concentrated on genetic sequences that are not parts of genes and are less functionally important, said Goodman.