Generation of shape complexity through tissue conflict resolution

It’s easy to visualize how a sheet of cells grows, but how does a sheet of cells form a complex, three-dimensional structure? Rebocho et al. describe how differential growth rates between cell layers and across the growing surface can produce a variety of complex shapes. As a model for shape complexity, the authors examine growth patterns in snapdragon (Antirrhinum majus) flowers (wild-type and mutant), and through their analysis along with computational modeling show that “orthogonal directional conflict plays a key role in generating out-of-plane deformations”. They further propose how gene activity, mechanical connectivity and the auxin transporter PIN1 can contribute to the generation of tissue conflicts and therefore shape. Don’t miss the movies! eLIFE 10.7554/eLife.20156