Like a rolling marble: Waddington’s landscape vibrant legacy and beyond

The epigenetic landscape has been introduced by the theoretical biologist Conrad Hal Waddington at the end of the 1930's as an image in order to represent the process of cellular differentiation during embryonic development. During the recent years this image has become iconic and massively used throughout several topics of biology, for example in the study of cancerogenesis and of cancer healing, of cellular tensegrity, of evolutionary biology, and in modelling differentiation seen at the single-cell level. Beyond its very intuitive nature, the success of the “Waddington's landscape” was also reinforced by recent formal studies showing that departing from its metaphorical aspect, the landscape could be described in mathematical terms under the auspices of dynamical systems theory. It is interesting to note that such a quest for an expression in mathematical terms of the epigenetic landscape accompanied Waddington's career. By introducing its landscape, Waddington intended not only to integrate development with genetics but also to incorporate them in an evolutionary framework. In this spirit, the aim of this workshop will be to bring together various communities, from mathematicians, to biologists, and from physicists to philosophers of science to debate the fertility of the landscape concept as well as to address open conceptual and modelling questions.