Structural redundancy in supracellular actomyosin network connections enables robust tissue folding

It is essential for the fate of an organism that key morphogenetic processes occur reproducibly. While much is known about how genetic regulation achieves robustness, less is known about how a tissue mechanically ensures reproducibility. Gastrulation is an indispensable stage of development. Drosophila fruit fly gastrulation is driven by myosin-dependent constriction and this robust large-scale movement requires coordinated forces at the tissue level. Yet, how the cytoskeleton is connected across the constricting tissue to realize shape change is unknown. We demonstrate a high degree of robustness in Drosophila gastrulation whereby ablating many cells doesn’t halt shape change. To understand this robustness, we integrated concepts from graph theory to analyze the connectivity of a supracellular network of mysoin connections that links cells in the tissue. We found that a dense meshwork of tissue scale connections ensures structural redundancy and that even when large numbers of connections are lost some paths across the tissue persists and folding proceeds. We propose that in the same way that redundancy ensures the large-scale function of telecommunication or transportation networks under localized failures, the organization of myosin activation enables robust morphogenesis.