Tissue material phase transitions & embryo pattern formation

The process of embryo development describes the emergence of a fully formed organism out of a single cell. Undoubtedly, this is one of the most astonishing phenomena of nature. And yet we experience it everyday with perfect familiarity, as the essential, necessary starting point of the unstoppable process of life and death. One can see the whole process as a play whose outcome is the result of a complex and delicate plot, made of balances and agreements among many processes, being the two most relevant the so called patterning and the so called morphogenesis: By patterning we refer to the execution of the genetic program leading to the different cell types and therefore, functions. In turn, morphogenesis accounts for the emergence of form. Form and Function unfold interlinked in a precise way in space and time. A fundamental question immediately arises: How do these two process explicitly interact, and how one interferes on the other? Before trying to answer the above question one has to understand the properties of the process of of the emergence of form. Contemporary research has shown that the developmental steps are by no means always smooth and, in some stages, dramatic, sudden shifts in the properties or structure of the embryo occur. These sudden shifts sometimes resemble what in physics is known as phase transitions for example, the melting of ice into liquid water. Indeed, strikingly, recent advances show that tissues forming the embryo of certain fish species transit from soft, melted states, to stiff, rigid ones and the other way round. This changes completely the view on how the forces and tensions define the form of the developing organism. Therefore, a second fundamental question arises: What does govern the state of the tissues? Using a combined approach that includes physics, computer simulations, empirical observations and genetic manipulations of real fish embryos, in this project we aim to answer the two above questions thereby disentangling 1/ What are the key elements defining the state of embryonic tissues, and how they impact into the changes of material properties and structure morphogenesis and 2/ How this perspective over morphogenesis, involving physics and geometry, influences the process of the emergence of function i.e., the patterning. The synergy between different disciplines will provide a deeper understanding of the mechanisms involved in the process of organism development. In addition, being able to control tissue-scale properties, both at the level of real systems and using computer simulations, will open possibilities for the fields of organ development and regenerative medicine.