The tree of evolution is the best way to situate and represent species in evolution. But that tree is still being built. For example, it is unclear when the branches of the chimpanzee and man were separated. The most widespread thing is that five or seven million years ago they were distributed, but, according to a published study, it was much later, about four million years ago.
The research has focused on genetic material, comparing certain areas of the genomes of man, chimpanzee, gorilla and orangutan. For this they have used the hidden model of Markov and calculated when the branches of these four species were distributed.
Opinions contrary to the results of the investigation have quickly appeared. One of the arguments is that there are fossils of the human branch four million years ago (the Australopithecus anamensis of Kenya). However, the authors claim that the chimpanzee and the man crossed after their separation.