Abstract: Neural crest cells are crucial in development, not least because of their remarkable multipotency. Early findings stimulated two hypotheses for how fate specification and commitment from fully multipotent neural crest cells might occur, progressive fate restriction (PFR) and direct fate restriction, differing in whether partially restricted intermediates were involved. Initially hotly debated, they remain unreconciled, although PFR has become favoured. However, testing of a PFR hypothesis of zebrafish pigment cell development refutes this view. We propose a novel ‘cyclical fate restriction’ hypothesis, based upon a more dynamic view of transcriptional states, reconciling the experimental evidence underpinning the traditional hypotheses.

Biography: Robert Kelsh did his undergraduate degree at the University of Cambridge, where he studied Natural Sciences, with a specialty in Zoology. He then did his PhD at the University of Cambridge with Michael Akam, studying the evolution of Hox gene expression patterns in insects. In 1992, he moved to the laboratory of Christianne Nüsslein-Volhard at the Max-Planck-Institute for Developmental Biology in Tübingen, as a NATO Post-doctoral Research Fellow within the team doing the first large-scale mutagenesis screen in zebrafish, focusing on mutants affecting pigment cell development. In 1994 he joined the laboratory of Judith Eisen at the Institute of Neuroscience, University of Oregon as a HFSP Long Term Postdoctoral Research Associate, beginning the analysis of some of these pigment mutants, before taking a position as a Lecturer at the University of Bath in 1997. His work has continued to focus on understanding the genetic mechanisms of pigment cell and peripheral nervous system development from the neural crest, and how pigment cells interact to generate the adult striped pigment pattern. He was promoted to Senior Lecturer and Reader, and to Professor in 2012.