Gavin Rylands de Beer: how embryology foreshadowed the dilemmas of the genome

Gavin de Beer is remembered, at best, as a shadowy figure among those who gradually built up our current view of evolution and the role of genetics. This view derives from the Modern Synthesis - the recognition that emerged in the 1930s that genetics can adequately explain Darwinian evolution and speciation through natural selection. I argue that de Beer's theories of embryology had a crucial role in the Modern Synthesis, and that his work indirectly continues to influence how we think about the genome, evolution and developmental biology.     

The organizer concept and modern embryology: Anglo-American perspectives

This paper analyses the origins of the Spemann-Mangold organizer concept of 1924 in relation to his earlier background and concepts. It traces the consequences and fate of the organizer, and related concepts (embryonic induction, gradients, fields) through subsequent phases in the evolution of developmental biology up to the present, primarily from a UK perspective, but also in the USA. The origins of Wolpert's concept of positional information of around 1970 are analysed; this markedly different model of embryogenesis effectively took the place of the organizer, following on from a generally assumed out-datedness of the corpus of Spemann's data and concepts. Explanations in terms of historical forces are suggested; events are seen as a historical causal chain. A crucial factor appears to have been the long-term neglect of morphogenetic cell movement as an integral component of an adequate induction-based model. The paper discusses the general inter-relation of history and science, and particularly the implications for current scientific practice, including the potential for conceptual distortions due to historical factors. It is argued that historical considerations need to be included as part of the use and critical assessment of basic concepts in science.