Stem cells

Definition

Undifferentiated or partially differentiated cells capable of self-renewal through indefinite or prolonged proliferation and of generating differentiated daughter cells that populate tissues or organs. In arthropods, stem cells maintain regenerative capacity in renewing tissues such as the midgut epithelium, germline, and epidermis, contrasting with progenitor cells that have limited division potential and precursor cells already committed to a specific fate.

Etymology

From English 'stem' (main trunk, line of descent) + 'cell', reflecting their position as the source of downstream cell lineages.

Example

In Drosophila melanogaster, intestinal stem cells located at the base of midgut epithelial crypts continuously divide to produce enteroblasts that differentiate into absorptive enterocytes and secretory enteroendocrine cells, enabling rapid replacement of the gut lining in response to damage or pathogen exposure.

Synonyms

• pluripotent cells (when applicable)
• multipotent cells (when applicable)

Related Terms

• progenitor cells
• precursor cells
• blast cells
• differentiation
• Regeneration
• germline stem cells
• somatic stem cells
• transit-amplifying cells

Usage Notes

Distinguished from progenitor cells by unlimited or greatly extended self-renewal capacity; distinguished from precursor or blast cells by lack of commitment to a single differentiated fate. In insect biology, 'stem cell' often specifically denotes the self-renewing population in the midgut or gonad, whereas 'progenitor' may describe more limited precursors in imaginal discs. The term is sometimes used loosely in older literature; modern usage reserves it for cells with demonstrated long-term self-renewal and lineage potency.