Clonogenic

Clonogenic is an adjective used in biology to describe cells that retain the capacity to proliferate and form a colony of descendants originating from a single progenitor cell. In cell culture, a clonogenic cell can give rise to a clonal population through repeated cell divisions, producing many daughter cells that occupy the same lineage. The term is widely used in cancer research, radiobiology, and stem cell biology to refer to the proliferative potential of cells and their ability to generate colonies.

A clonogenic assay is a laboratory method that tests the reproductive viability of cells after a treatment or exposure. In such assays, cells are plated at low density so that colonies arise from single cells. After a defined incubation period, colonies are counted; a colony is commonly defined as containing at least 50 cells. The plating efficiency is the proportion of seeded cells that form colonies, and the surviving fraction after treatment is the number of colonies formed divided by the number of cells plated, adjusted for plating efficiency. Clonogenic assays are considered a gold-standard measure of reproductive cell death, particularly in radiobiology and chemotherapy studies.

Applications include assessing stem cell self-renewal and proliferative capacity, evaluating cancer cell resistance to therapy, and characterizing normal tissue toxicity. In hematology, CFU assays (colony-forming units) probe progenitor cell function, while in microbiology, clonogenicity refers to a single organism’s ability to form a colony on solid medium.

Limitations include reliance on single-cell cloning, potential cell clumping, and the need for appropriate growth conditions; results may vary with cell type and assay duration.