HHMI- Holiday Lectures on Science. Potent biology: stem cells, cloning and regeneration. Introduction a speaker: Nadia Rosenthal, Ph.D We have lost ability to regenerate. No matter where it is amputated limb will "know" where it was cut, and what to grow. CD59 is a molecule which's concentration increases going further away from the body. Does CD59 contest marks, addresses cell's position?