Organelle Fission. Crossing the Evolutionary Divide

Among the products of the genome sequencing revolution are dramatic new insights into the evolutionary basis for cellular structure-function relationships. An example of this is the information beginning to accumulate regarding the key players and processes involved in the division of chloroplasts in plant cells and, more recently, in the division of mitochondria. Both types of organelles arose from prokaryotic endosymbionts related most closely to modern-day Cyanobacteria in the case of chloroplasts Though most of the genetic functions present in the original endosymbionts have been transferred to or taken over by the nucleus (Martin and Herrmann, 1998), the prokaryotic signatures of many organellar processes are still evident in the similarities of the associated proteins to those in extant prokaryotes.