ABSTRACT
The evolutionary development of the Primates has resulted from the sum of the processes of cladogenesis and anagenesis. Cladogenesis, or phylogenetic branching, is the splitting of a species into two or more species and the ensuing divergence of these species from each other. There are a number of questions concerning the phylogenetic relationships of various living Primates. The chapter presents an immunological theory of primate evolution and reviews the results of a comparative serological study of the serum proteins of the Primates. The immunological considerations suggest that significant strides toward the development of a hemochorial placenta occurred in the line of human ancestry during the early stages of primate phylogeny when man’s prosimian ancestors still had a relatively short period of gestation. A comparative study of the serum proteins of the Primates is in progress. The principal techniques are two-dimensional starch-gel electrophoresis and agar-gel precipitin testing with a variety of antisera to proteins of different Primates.
