Stem cells |
Undifferentiated cells that can differentiate into specialized cell types and can divide through mitosis to produce more stem cells, either for a limited number of divisions or potentially as an immortal cell clone. |
Unipotent/oligopotent stem cells |
Stem cells that can differentiate into only one/few cell types. For example, vertebrate muscle satellite cells are stem cells that produce myoblasts that form into muscle cells (see Fig. 8). |
Multipotent stem cells |
Stem cells that can differentiate into many cell types. An example would be the I-cells of hydras (see text). |
Pluripotent somatic stem cells |
Stem cells that can differentiate into all known somatic cell types of an animal. |
Primordial germ cells |
The initial cells of a developing germline, which is capable only of forming germ cells (gametogenesis). |
Totipotent stem cells |
Pluripotent stem cells that also are capable of gametogenesis. Examples would be mammalian zygotes and early embryos. Choanocytes and archeocytes of sponges and neoblasts of planaria may be totipotent or pluripotent, depending on various authors’ definitions and descriptions (see text). |