Early-stage embryo as an active self-tuning soft material

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Embryonic development is a fascinating biological process in which a new organism is formed from a single cell, the fertilised egg or zygote. The process involves many rounds of cell growth and divisions to generate more cells, differentiation to generate different types of cells, and movements in order to arrange them in the complex structures of a functioning living organism. While in mammals the embryo receives necessary nutrients by being connected to the bloodstream of the mother, in the case of birds the nutrients come from the egg. Once the development of an egg is started, it is fully autonomous, the DNA of the zygote and the content of the egg contain the blueprint for building the entire organism. This requires a carefully timed and executed set of steps that involve complex biochemical and physical interactions between a rapidly growing number of differentiating cells.Gastrulation is an essential step in early development during which a single-layered sheet of cells, the blastula, transforms into a three-layered structure known as the gastrula. It sets up the layout of the body plan and when not executed properly results in abortion of development and, in milder cases, leads to a wide range of congenital defects. Gastrulation is highly evolutionally conserved between different vertebrate animal species, ranging from fish and frogs, via lizards and birds to mammals, including humans. Studying gastrulation, therefore, plays an important role in understanding the evolution of complex life. Gastrulation in birds shares a lot of similarities with the early development of human embryos. However, the fact that their embryos develop outside the mother animal, can be easily cultured, and are accessible to experimental observation and manipulation, make bird embryos an excellent model system for understanding the principles of early human development. The goal of this project is to identify, characterise, and understand essential biochemical and physical processes that drive gastrulation. Recent advances in live imaging showed that successful gastrulation depends on intimate coordination of gene expression, biochemical signalling, and mechanical stresses spanning from subcellular to cell to tissue scales. Therefore, understanding gastrulation is a complex task that requires shared expertise and close collaboration of a team of researchers with backgrounds in cell and developmental biology and physics. Here, we assemble such a team of experts. The team will use a combination of in-vivo and in-vitro imaging, mechanical, chemical, and genetic manipulations in conjunction with state-of-the-art modelling to understand how cell-level processes coordinate to drive complex motion patterns within the early chick embryo that allow cells to position themselves at the correct place in the embryo. Results of this study will have a long-lasting impact not only in developmental biology but on the general understanding of how biochemical and physical cues coordinate in living systems. Understanding the principles behind embryonic development would, therefore, be relevant to our understanding of the origin and evolution of life on Earth. It would also impact different branches of medical and biomedical research, ranging from understanding, preventing, and even treating congenital diseases, to treating severe injuries, to designing and building artificial tissues and organs. Beyond biomedical applications, being able to mimic embryonic development would revolutionise materials science by providing bottom-up fabrication processes -- instead of specifying the precise location of each component in complex circuitry in a top-down fashion, as it is the case today, one would "program" the building blocks with a set of rules and properties and let them self-assemble into a complex machine.