A Tribute to Lewis Wolpert and His Ideas on the 50th Anniversary of the Publication of His Paper 'Positional Information and the Spatial Pattern of Differentiation'. Evidence for a Timing Mechanism for Setting Up the Vertebrate Anterior-Posterior (A-P) Axis.

This article is a tribute to Lewis Wolpert and his ideas on the occasion of the recent 50th anniversary of the publication of his article 'Positional Information and the Spatial Pattern of Differentiation'. This tribute relates to another one of his ideas: his early 'Progress Zone' timing model for limb development. Recent evidence is reviewed showing a mechanism sharing features with this model patterning the main body axis in early vertebrate development. This tribute celebrates the golden era of Developmental Biology.