[Comparison of the karyotype of the orangutan (Pongo pygmaeus) to those of man, chimpazee, and gorilla].

Various banding thechniques were employed to compare the karyotype of the Orang-utan (Pongo pygmaeus) with those of Man, the Chimpanzee, and the Gorilla. The following was concluded: 1) Almost all the bands are common, their analogy being close to 99%. The four species derive, therefore, from a common ancestor. The rearrangements which occurred during evolution were generally balanced; 2) The analysis of rearrangements shows that the Orang-utan, then the Gorilla, then the Chimpanzee, and lastly Man were derived in that order from the common stemline.