How Does a Zebrafish Grow a New Tail?

If a zebrafish loses a chunk of its tail fin, it will grow back within a week. Like lizards, newts, and frogs, a zebrafish can replace surprisingly complex body parts. A tail fin, for example, has many different types of cells and is a very intricate structure. It is the fish version of an arm or leg.

Scientists have discovered some of the genes and cell-to-cell communication pathways that enable zebrafish to restore their tail fins. The ability involves creating cells that can take any number of new roles. This can be done by re-programming cells that already have a given function or by activating resident stem cells. Through a series of signals, cells waiting for their calling learn which spot to take to help form the embryo, what kinds of cells to become there, and how many cells like themselves should be reproduced.