The ability to regenerate lost body parts is unevenly distributed among higher organisms, the scientists said. Among vertebrates, some amphibians are able to replace lost limbs, but mammals are unable to regenerate complex appendages.

The researchers -- Hans Rolf and colleagues from the University of Goettingen and the University of Hildesheim -- said the epimorphic regeneration of appendages might involve stem cells created through reprogramming of differentiated cells or through the activation of resident stem cells.

Rolf and colleagues said their findings strongly support the view that the growth of primary antlers, as well as the annual process of antler regeneration, depend on the periodic activation of mesenchymal stem cells.

They said understanding the mechanisms behind that unique regeneration process could have an important impact on the emerging field of regenerative medicine.

The findings appear in the online journal PLoS One