Morphogen gradients are known to guide spatial patterning, but can they also encode time? Vetter and Iber propose that a co-expanding morphogen source generates transient signals, allowing cells to measure time without additional molecular clocks. The Sonic Hedgehog gradient in the mouse neural tube is used to show how this mechanism can act as a timer. Opposing gradients synchronize differentiation across the tissue, providing a simple, widely applicable strategy for coordinating space and time during development.

Nature Physics - Carcinoma subtypes are normally linked to specific genetic alterations, but tissue mechanical changes also play a role. Now, aberrant morphologies resembling bladder carcinoma are...