The human body contains ~ 3.72 x 10¹³ cells and 200 different cell types. Generating the right number and types of cells is vital for embryogenesis, morphogenesis and tissue homeostasis. Such cellular diversity can be generated and maintained through asymmetric cell division (ACD), an evolutionary conserved process. ACD can be manifested in sibling cell size differences, distinct biochemical and molecular identities, or differences in subsequent division patterns.

Biological systems can be quite complex for intuitive interpretations. This is especially true in developmental biology, where robust patterns are established and maintained dynamically in ever-changing and inhomogeneous multicellular environments. Despite the discovery of many key regulatory modules in growth, morphogenesis and fate specification, we still understand little on how such modules are precisely executed, particularly when small initial differences may induce sharp segregation of developmental decisions.