Can laboratory model systems instruct human limb regeneration?

Regeneration has fascinated scientists since well before the 20th century revolutions in genetics and molecular biology. The field of regenerative biology has grown steadily over the past decade, incorporating advances in imaging, genomics and genome editing to identify key cell types and molecules involved across many model organisms. Yet for many or most tissues, it can be difficult to predict when and how findings from these studies will advance regenerative medicine. Establishing technologies to stimulate regrowth of a lost or amputated limb with a patterned replicate, as salamanders do routinely, is one of the most challenging directives of tissue regeneration research. Here, we speculate upon what research avenues the field must explore to move closer to this capstone achievement.