Mechanochemical Active Feedback Generates Convergence Extension in Epithelial Tissue

Convergent extension (CE) is a morphogenetic process that occurs during development. It is conserved across many different species, types of tissues, and stages of development [1–4]. During convergent extension, a region of sheetlike (epithelial) tissue elongates in one direction (the long axis) and contracts perpendicular to it. Convergent extension plays a key role in a variety of developmental processes, such as primitive streak formation in chick embryos [5,6] and drosophila germ band extension [7,8] which are important parts of gastrulation. This is the topological inversion process shared by nearly all multicellular animals and some plants [9] that leads to cells taking up their correct positions within the embryo.