Dissecting the establishment of early embryonic geometries

During the early stages of animal development, the embryo starts as a single cell formed after fertilization. This cell divides rapidly into multiple cells of smaller size, but the overall volume of the embryo stays the same. During this time, these cells do not move or die, instead, their arrangement is determined solely by how they divide herein referred to as cell division pattern. The position of each cell is crucial for the embryo to develop into an adult. Thus, understanding how cell position is controlled is key to studying embryonic development. Over the years, scientists have identified several factors that influence how cells divide. These include cellular factors, like molecules that dictate how and when cells divide and how they stick together, as well as physical factors, such as the stiffness of cells and general energy principles. However, its still unclear how all these factors work together in an embryo. Different species, like humans, fish, and invertebrates, show a wide variety in their cell division patterns, which raises questions about why similar factors can lead to different outcomes in different animals. My project will improve our understanding of how these cellular and physical factors combine to shape the cell division pattern. I will use the sea squirt Phallusia mammillata, because their embryonic development is very robust and the embryos are fully transparent, making them easy to use for this project. Using different cellular, molecular and biophysical laboratory techniques, I will characterize how the sea squirt embryo develops. I will use this knowledge to manipulate their development and learn how different molecular and physical factors affect their development. In parallel and together with theoretical scientists, we will create predictions about how the different factors affect the cell division pattern to complement the laboratory methods. Finally, I will use methods to separate the embryo into individual cells and then reassembling them in specific ways. This will help me understand how the position of the cells can lead to incorrect cell division patterns and developmental errors. This interdisciplinary approach, combining cellular and molecular laboratory techniques and physical theoretical approaches, will be key to understanding how the cell division pattern is controlled during embryonic development. My project will contribute to research in the developmental biology field and contribute to elucidate the basic principles behind embryonic development.