Planaria

Humans have always sought for eternal life as I wrote in previous post, and that often includes the ability to regenerate own body parts like arms and organs. That is of course impossible for humans and it is also denied for advanced animals. However, humans again found an animal that can regenerate any parts of its body in short time. The animal is called planaria, a group of flat worms. It has head with brain, stomach, and tail. It's very rare in animal world to possess an ability to regenerate such a complicated organ like brain. Its largest mystery is that when planaria is cut into many pieces, all of the pieces can identify the correct direction and repair. There is one story that a researcher cut planaria into 107 pieces and all of them were completely repaired and became 107 planarias. Its special cells are always ready to differentiate to any kinds of cells so many studies are taking place to somehow use this cell to repair human organ or body parts. The recent discovery of iPS cell is closely related to the study of planaria. Scientists are now trying to create artificial heart by using this cell.