 Independently of Motoo Kimura, Jukes (with Jack King) proposed in 1969 that the evolution of proteins is primarily driven by genetic drift acting on mutations that are neither beneficial nor deleterious—the neutral theory of molecular evolution.Despite the provocative paper ("Non-Darwinian Evolution"), he was not a prominent participant in the ensuing "neutralist-selectionist debate"; defense of the neutral theory was primarily left to others, especially Kimura.In 1971, Jukes was one of the founders of the "Journal of Molecular Evolution"; his subsequent work with molecular evolution focused especially on the origin and evolution of the genetic code.