"We conclude — unexpectedly — that there is little evidence for the neo-Darwinian view: its theoretical foundations and the experimental evidence supporting it are weak, and there is no doubt that mutations of large effect are sometimes important in adaptation. We hasten to add, however, that we are not "macromutationists" who believe that adaptations are nearly always based on major genes. The neo-Darwinian view could well be correct. … We hope to encourage evolutionists to reexamine this neglected question and to provide evidence to settle it."