PHYLOGENETIC RELATIONSHIPS BETWEEN MAN AND THE APES: ELECTROPHORETIC EVIDENCE

Phylogeny was traditionally the subject matter of paleontology and comparative anatomy. However, in recent years it has become apparent that proteins and nucleic acids (the so-called "informational" macromolecules) store a wealth of information concerning evolutionary history. Protein sequencing, immunology, electrophoresis, and DNA hybridization are among the molecular techniques used in phylogenetic studies. These techniques have generally confirmed previously established evolutionary relationships, and in many cases have provided information where little or none was available from the fossil record. There are instances, nevertheless, when molecular studies lead to conclusions contrary to those reached by paleontologists or comparative anatomists. One case of disagreement concerns the evolutionary history of the hominoidsi.e., man, the great apes, and the Hylobatidae (gibbons and siamang). Paleontologists and comparative morphologists place the Asiatic orangutan much closer to the African apes (the gorilla and the chimpanzee) and to man than to the two other genera of Asiatic hominoids, the siamang and the gibbon. Molecular evolutionists, on the contrary, have proposed that the orangutan is much less closely related to the African apes and man, and may be as removed from these as the siamang and gibbon. Disagreement also exists with respect to the phylogenetic propinquity of the chimpanzee, the gorilla, and man. Paleontologists and comparative morphologists