Decaying and expanding Erk gradients process memory of skeletal size during zebrafish fin regeneration

Nature Physics, Published online: 24 August 2026; doi:10.1038/s41567-026-03426-w

Zebrafish can regenerate amputated fins back to their original size. It is now shown that gradients in extracellular signal-regulated kinase activity act as rulers during fin bone regeneration.