African spiny mice (genus Acomys) can shed up to 60% of the skin on their backs.

J. GOHEEN

Two species of African spiny mouse have been caught at something no other mammal is known to do — completely regenerating damaged tissue1. The work could help improve wound healing in humans.

The species — Acomys kempi and Acomys percivali — have skin that is brittle and easily torn, which helps them to escape predators by jettisoning patches of their skin when caught or bitten. Researchers report today in Nature that whereas normal laboratory mice (Mus musculus) grow scar tissue when their skin is removed, African spiny mice can regrow complete suites of hair follicles, skin, sweat glands, fur and even cartilage.

Tissue regeneration has not been seen in mammals before, but it is common in crustaceans, insects, reptiles and amphibians. Some lizards can regrow only their tails, whereas some salamanders can regenerate entire limbs, complete with bones and muscle.

The researchers say that their next step will be to work out the molecular mechanisms and genetic circuits that direct the regeneration process. It’s unlikely that these mice have evolved an entirely new method of regrowing tissue, says Ashley Seifert, a developmental biologist at the University of Florida in Gainesville, who led the study. Rather, the genes that direct regeneration in salamanders are probably switched off in mammals, but have been switched back on in African spiny mice.