Editing Cellular differentiation (section)

=== Asymmetric cell division ===
Other important mechanisms fall under the category of [[asymmetric cell division]]s, divisions that give rise to daughter cells with distinct developmental fates. Asymmetric cell divisions can occur because of asymmetrically expressed maternal '''cytoplasmic determinants''' or because of signaling.<ref name="Rudel" /> In the former mechanism, distinct daughter cells are created during [[cytokinesis]] because of an uneven distribution of regulatory molecules in the parent cell; the distinct cytoplasm that each daughter cell inherits results in a distinct pattern of differentiation for each daughter cell. A well-studied example of pattern formation by asymmetric divisions is [[Drosophila embryogenesis#Anterior-posterior axis patterning in Drosophila|body axis patterning in Drosophila]]. [[RNA]] molecules are an important type of intracellular differentiation control signal. The molecular and genetic basis of asymmetric cell divisions has also been studied in green algae of the genus ''[[Volvox]]'', a model system for studying how unicellular organisms can evolve into multicellular organisms.<ref name="Rudel" /> In ''Volvox carteri'', the 16 cells in the anterior hemisphere of a 32-cell embryo divide asymmetrically, each producing one large and one small daughter cell. The size of the cell at the end of all cell divisions determines whether it becomes a specialized germ or somatic cell.<ref name="Rudel" /><ref name="Kirk">Kirk MM, A Ransick, SE Mcrae, DL Kirk; The relationship between cell size and cell fate in ''Volvox carteri''. ''Journal of Cell Biology'' 123, 191-208, 1993 {{cite journal | vauthors = Kirk MM, Ransick A, McRae SE, Kirk DL | title = The relationship between cell size and cell fate in Volvox carteri | journal = The Journal of Cell Biology | volume = 123 | issue = 1 | pages = 191–208 | date = October 1993 | pmid = 8408198 | pmc = 2119814 | doi = 10.1083/jcb.123.1.191 }}</ref>