Multipotency

Multipotency is the capacity of a stem cell to produce a limited range of specialized cells, usually all the cell types of one tissue or organ system. It sits in the middle of the ladder of developmental potential: below totipotent cells, which can build a whole organism, and pluripotent cells, which can make any cell of the body, but above oligopotent cells, which make only a few types, and unipotent cells, which make just one.

Most stem cells in the fetus and the adult are multipotent. Hematopoietic stem cells make all blood and immune cells but not nerve or liver cells; mesenchymal stem cells form bone, cartilage and fat; neural stem cells make neurons and glial cells; and stem cells in the skin and the lining of the gut constantly renew those tissues. Like all stem cells, a multipotent cell can also renew itself, dividing to keep its own numbers steady while some of its daughters specialize. Signals from its surroundings, called the stem cell niche, help decide which path each daughter takes.

Multipotent cells underpin most established stem cell treatments, above all bone marrow transplants. They are easier to obtain from adults and raise fewer ethical questions than embryonic stem cells, but their narrow range means they cannot be used to make any tissue at will.