Comment by throwup238
18 hours ago
Considering that there aren’t any mammals that can regrow appendages, chances are adding an appendage would be impossible with gene editing because it would require editing both the mother and offspring to support novel embryonic development.
I seem to think that human children can regrow the tips of their finger if it is cut off (I think the nail is ok, not the joint) though I don't know where I learned that, perhaps a first aid course. I've never tried it though.
That is correct, as long as the injury doesn’t take out the nail bed. That implies that there is some sort of growth factor involved with the nail bed as a signaling center, but regrown finger tips are a very simple case compared to actual appendages.
Finger tips are mostly fatty soft tissue minus the muscle, which is known to regenerate. Stuff like nerves are a completely different issue and children who regrow finger tips usually lose finer sensory input like two point discrimination.