Resumen
Alan Turing died in 1954 in his laboratory after eating a cyanide-laced apple. During his last years, Turing had become an experimentalist, interested in bio-chemical systems. He had proposed a reaction-diffusion model in his 1952 paper entitled "The Chemical Basis of Morphogenesis," putting forth his hypothesis of biological pattern formation. Turing's models describe how the concentration of certain substances (called morphogens) distributed in space change under two continuous-time processes: local chemical reactions, in which the substances are converted into each other, and diffusion, which causes the substances to spread out in space. Pattern formation in biology is better understood by hybrid automata, in which the genes form complex discrete modes with their own program for state-transitions, while exhibiting continuous dynamics as the system dwells in various modes.