Department of Mathematics, North Carolina State University, Raleigh, North Carolina 27695-8205, USA.
Branching morphogenesis is ubiquitous and important in creating bulk transport systems. Branched ducts can be generated by several different mechanisms including growth, cell rearrangements, contractility, adhesion changes, and other mechanisms. We have developed several models of the mechanics of cleft formation, which we review. We discuss the implications of several candidate mechanisms and review what has been found in models and in experiments.