The Song of the Cell: An Exploration of Medicine and the New Human

by Siddhartha Mukherjee

It’s tempting to think of the stem cell as an ancestral great-great-great-grandfather or -grandmother. Its progeny give rise to more progeny, resulting in a vast lineage that arises from a single great-great-great-grandfather cell. But to be a true stem cell, this must be the oddest of great-great-great-grandfathers. It must also give birth to a copy of itself that can maintain the replenishment of the lineage. This great-great-great-grandfather, besides birthing a child (that will go on to establish an enormous lineage), must also birth a copy of itself—an eternally alive twin. And once this self-renewing great-great-great-grandfather is born, the process of regeneration can become limitless. There’s a mythic quality to such a setup—and indeed, in myths, one often finds attempts by powerful kings or Gods to make backup twins (dolls, voodoo objects, souls secretly stored in animals, twin personhoods locked in amulets) to reboot themselves and their clan should something terrible happen. Like most real stem cells, these mythic doubles usually lie dormant—quiescent—until an injury wakes them up. And then they awake and reseed the whole clan. It results not in birth but rebirth.