Motoo Kimura, author of the book, The Neutral Theory of Molecular Evolution, published in 1983, more than a hundred years after Darwin's masterpiece.

After the discovery of the structure of DNA molecules by Crick and Watson in 1953, Kimura knew that genes are molecules, carrying genetic information in a simple code. His theory applied only to evolution driven by the statistical inheritance of molecules. He called it the Neutral Theory because it introduced Genetic Drift as a driving force of evolution independent of natural selection.

Sewall Wright, then 98 years old but still in full possession of his wits. He gave me a first-hand account of how he read Mendel's paper and decided to devote his life to understanding the consequences of Mendel's ideas. Wright understood that the inheritance of genes would cause a fundamental randomness in all evolutionary processes. The phenomenon of randomness in evolution was called Genetic Drift. Kimura came to Wisconsin to learn about Genetic Drift, and then returned to Japan. He built Genetic Drift into a mathematical theory which he called the Neutral Theory of Molecular Evolution.