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Cells seeking paths through the body’s tangle of tissues might adapt the navigational strategy of Hansel and Gretel. In the Brothers Grimm tale, the lost kids dropped pebbles and bread crumbs along a wooded trail to help lead them back out of a freaky forest.
Instead of using markers telling them where to go, though, cells might leave behind repellent molecules telling them where not to go.
In a new study, scientists suggest these markers help trailblazing cells move away from areas where they’ve gotten stuck, such as confusing dead ends and tricky corners.
“I think it’s a really nice idea that cells could be using something like this, a simple mechanism that allows them to navigate through these complex environments,” says biologist Iain Couzin of Princeton University, who was not involved in the study.