Are humans capable of regenerating missing appendages? What else can humans regenerate?
(Submitted by Jeremy Jackson, Gadsden, Alabama)A: Compared with fish and amphibians, humans have a very limited capacity to regenerate lost appendages. Despite extensive research with amphibians, scientists do not know precisely why regenerative ability is absent in mammals, especially since the course of evolution might be expected to promote retention of such a valuable property. It is hoped that further research will lead to medical treatments promoting regeneration of appendages and other organs.The best explanation for this lack of regenerative capacity is that evolutionary development of mammals tended to favor rapid healing and scarring of wounds rather than perfect regeneration or reconstitution of injured body parts. During regeneration, injured tissues revert to an embryonic condition and replay events that formed the structure in the embryo. A regenerating appendage is “embryonic,” nonfunctional, soft, and extremely delicate. Despite the apparent value of regeneration, the s
