There was an excellent colorful review of the possible evolution of primates in a recent National Geographic. I am not sure exactly which one, but it was between January 1993 and April 1993. That is almost certain. Humans and gorillas have the exact same number and types of bones. Humans and chimps have the exact same hemoglobin proteins in their blood.
Gorillas only differ by one a amino acid or two.
That humans and other apes share a common ancestor is as much a scientific fact as that the earth revolves around the sun. Neither have been directly observed, but they are so well supported by such a huge preponderance of evidence as to leave little doubt. The only debate theses days among scientists regarding our relationship to the gorillas is whether we are more closely related to them or the chimpanzees, and even there, most are leaning towards chimps. Argonne National Laboratory, Division of Educational Programs, Harold Myron, Ph.D., Division Director.