Stem Cell Quotes

“Though the Drosophilia ovary is a structure with a different purpose - one designed to make fly eggs, not blood cells - the ovary, and specifically, the substructure of the ovary known as the 'germarium', have similarities with what was described for hematopoiesis. The organization of the cells that make up the germarium can be likened to a knitted winter hat pulled over the wearer's head. The extreme end - the pompon - comprises a set of cells called the 'terminal filament' cells; the top of the hat is formed by anterior 'cap' cells; and the sides of the hat are made up of more lateral 'inner sheath' cells that surround the GSCs themselves. Within this small cluster of cells, precise positions matter. When a GSC divides in two, one cell remains in contact with the cap cells and the other loses this immediate proximity. The cell that remains in contact with cap cells remains a GSC. The more posterior-positioned cell, by contrast, goes on to form an egg. A similar setup exists in the Drosophilia testes, in which 'hub' cells sit immediately anterior to the male GSCs. A question arises, what is special about the proximity of a GSC to a cap cell that keeps one daughter of a recently divided stem a stem cell while its sister goes on to form an egg?”
― Stephanie Elizabeth Mohr, First in Fly: Drosophila Research and Biological Discovery