Protein amino acid sequences are not directly very informative about the emergence of man from his immediate primate ancestry. But this could be because too little attention has been given to protein systems most relevant to the progress of hominization, those that, through their cell-surface action or enzymatic control of biosynthesis of other key proteins or hormones, can modulate the course of cell and tissue development, and so determine changes in tooth architecture, bone and tissue structure, brain and nerve cell development, etc. There are also the histones and other proteins associated with DNA in the genetic material, which have some modulating influence on gene expression. The whole process of carrying information from the genetic material to a species-reproducible morphology is through a cascade of multiple interlocking systems involving proteins at every turn. It is through changes in balance within these systems, and subsequent selection pressures, that the modulations of primate morphology and behaviour that constitute hominization have proceeded, and the process must be understood in terms of cytobiochemistry to give a fully detailed definition of the evolving human genome.