Professor Philip Maini works in the Centre for Mathematical Biology at the University of Oxford. Turing’s seminal paper “The chemical basis of morphogenesis”, published in 1952, proposed that pattern formation in early embryonic development was an emergent, or self-organising, phenomenon driven by diffusion. This ingeneous and highly counter-intuitive idea has formed the basis for an enormous number of subsequent studies from both experimental and theoretical viewpoints. Maini critiques the model, considers applications to skeletal patterns in the limb, animal coat markings, fish pigmentation and hair patterning, and describes how present-day research is still influenced by this paper. The Turing Research Symposium was organised by the Royal Society of Edinburgh and the University of Edinburgh School of Informatics in partnership with SICSA and supported by Cambridge University Press.