The question of how man has emerged must be as old as human thought itself. However, it was not until last century that, amidst a storm of opposition and highly emotional criticism, man was first conceived as a product of evolution rather than creation. Moreover, it is not yet thirty years since the chemical composition and molecular structure of the hereditary material was fully understood or the chromosome number of man became known. It should not be surprising then, to find how little, at present, we understand how our genes and chromosomes operate, and how they have evolved during...