Figure 2.

Presence of centriole/basal body structure correlates with the presence of flagella/cilia. (a) Simplified taxonomic tree representing major eukaryotic groups in different colors. Unikonts include eukaryotic cells that, for the most part, have a single emergent flagellum divided into opisthokonts (propel themselves with a single posterior flagellum; metazoans, fungi and choanoflagellates) and Amoebozoa. Bikonts include eukaryotic organisms with two emergent flagella. Branch color code: purple, opisthokonts; blue, Amoebozoa; green, plants; yellow, alveolates; orange, stramenopiles; rose, Rhizaria; brown, excavates and discicristates. Adapted with permission [19]. (b) We represent the symmetry and number of microtubules present in centrioles/basal bodies that are either nucleating (basal body, 2) or not nucleating axonemes (centriole within centrosome, 1) and in axonemes (3) as well as the presence/absence of a central microtubule pair. Note that the presence of the centriole/basal body structure (2) correlates with the presence of flagella (2 versus 3) but not centrosomes (1 versus 2). Adapted from © Carvalho-Santos et al., 2011. Originally published in J Cell Biol.