A new study presents intriguing evidence that large bone injuries might trigger a repair strategy in adults that recapitulates elements of skeletal formation in utero. Key to this repair strategy is a gene called Sonic hedgehog. In this study, researchers took a close look at how mice are able to regrow large sections of missing rib — an ability they share with humans, and one of the most impressive examples of bone regeneration in mammals. To their surprise, the scientists observed an increase in the activity of Sonic hedgehog (Shh), which plays an important role in skeletal formation in embryos, but hasn’t previously been linked to injury repair in adults.
