Stem Cell Research Blog

The classical definition of a stem cell requires that it possess two properties

Self-renewal

The ability to go through numerous cycles of cell division while maintaining the undifferentiated state.

Potency

The capacity to differentiate into specialized cell types. This requires stem cells to be either totipotent or pluripotent - to be able to give rise to any mature cell type.

This is the strictest definition*.

*Multipotent or Unipotent progenitor cells are sometimes referred to as stem cells.

To understand stem cells better, we need to understand the concept of potency.  Potency defines the potential to differentiate into different cell types. of the stem cell.

Totipotent or omnipotent stem cells

These cells can differentiate into embryonic and extraembryonic cell types. Such cells can construct a complete, viable, organism. These cells are produced from the fusion of an egg and sperm cell.

Pluripotent, embryonic stem cells giving rise to other specialised cells. Image Credit Wikipedia

Pluripotent stem cells

These are  the descendants of totipotent cells and can differentiate into nearly all cells i.e. cells derived from any of the three germ layers.

Multipotent stem cells

These can differentiate into a number of cells, but only those of a closely related family of cells.

Oligopotent stem cells

These cells can differentiate into only a few cells, such as lymphoid or myeloid stem cells.

Unipotent cells

These cells can produce only one cell type, their own,  but have the property of self-renewal.