Nature 476, 57–63 (2011)

Credit: © 2011 NPG

The gut in vertebrates is a folded tube attached to the mesentery — a sheet-like structure that connects the tube to the abdominal wall. Attempts have been made to explain the origin of the gut's characteristic looped patterns, which are reproducible in individual organisms but show variations across species, by invoking distinct diets and packing constraints in body cavities. Mahadevan and colleagues, using a combination of experiments, simulations and scaling laws, now show that the size and shape of the folds in the vertebrate gut can be described quantitatively by a simple theory that accounts for the differential growth between the tube and the mesentery, and for the geometric and elastic properties of these two tissues. To show this, they built a synthetic replica of the gut that consists of a stretched thin rubber sheet (the mesentery) stitched along its boundary to an unstretched, straight rubber tube — the imposed differential strain mimicking the differential growth of the two tissues. When allowed to relax, the rubber model folded into a structure reminiscent of the natural gut.