Darwin famously thought of evolution as a force for creation and improvement. Evolution, in his eyes, was synonymous with natural selection and survival of the fittest – a process that optimizes life to thrive in its environment and produce greater numbers of offspring. A century later, however, the great population geneticist Motoo Kimura challenged this view with his ‘neutral theory’ of evolution (Kimura, 1968). While the neutral theory was more difficult to understand than Darwin’s approach, and hence did not capture the public imagination in the same way, it provided the key insight that helped evolution to make sense in the light of molecular biology.