 Mathematical modeling suggests that under certain circumstances, natural selection favours the evolution of canalization that is designed to fail under extreme conditions.If the result of such a failure is favoured by natural selection, genetic assimilation occurs.In the 1960s, Waddington and his colleague the animal geneticist J. M. Rendel argued for the importance of genetic assimilation in natural adaptation, as a means of providing new and potentially beneficial variation to populations under stress, enabling them to evolve rapidly.