 However, fossils assigned to the genus "Homo" have been found that are older than "A. africanus".Thus, the genus "Homo" either split off from the genus "Australopithecus" at an earlier date (the latest common ancestor being either "A. afarensis" or an even earlier form, possibly "Kenyanthropus"), or both developed from a yet possibly unknown common ancestor independently.According to the Chimpanzee Genome Project, the human–chimpanzee last common ancestor existed about five to six million years ago, assuming a constant rate of mutation.