The centriole and the cell

The endosymbiotic theory of the origin of the centriole is found lacking as no DNA has been found in the structure. The centriole is related to the ribosome in that it is a structure nucleated by RNA. This RNA (morphic) has the property of localizing itself at the site of the old centriole before nucleating a new one. The implication of this property of the localization of RNA is discussed with respect to the way the eukaryotic cell determines its shape.