Formation of the synthetic theory as the orthodox view

In the previous chapter, a history of the theories on the mechanism of evolution was presented — a history leading to the establishment of classical population genetics by Fisher, Haldane and Wright early in the 1930s. In discussing the synthesis of Darwinism with Mendelian genetics, there is one more name that we should not forget. This is H.J. Muller who by the early 1920s had elucidated the fundamental nature of gene mutation and its bearing on evolution by natural selection.

His dramatic demonstration of the mutagenic action of X-rays (Muller, 1927) for which he was later awarded the Nobel Prize is well known. But less well known are his fundamental contributions to our understanding of the mechanism of evolution. He propounded forcefully the view that the basis of adaptive evolution by natural selection lies in the remarkable property of the gene that not only is each gene self-reproducing, but also mutated forms of a gene are again self-reproducing (Muller, 1922, see also p. 175 of Muller, 1962). Natural selection, then, can be defined as the differential multiplication of mutant types. He went so far as to claim (Muller, 1929, see p. 188 of Muller, 1962) that the gene is the very basis of life.