Figure 3

Last eukaryotic common ancestor (LECA) Rabs and their evolution in different phyla. In this overview, we show the changes of LECA Rabs in a number of different phyla. The most elaborate changes to the repertoire are displayed. For example, the transition to metazoan multicellularity gave rise to a large number of new, mainly secretory, Rabs. This can be seen by the change from choanoflagellates (Monosiga brevicollis) to metazoans. Similarly, there was a loss of LECA Rabs in fungi; basal fungi still possess a large number of these Rabs, but Basidiomycota have already lost three and the Saccharomycotina another one. Early in their evolution, plants lost a number of LECA Rabs, but then expanded the remaining Rabs into families. Particularly in plants there was a number of Rabs that we could only locate in one species: Rab24 was found only in the algae Coccomyxa, Rab28 was found only in the algae Micromonas, and for angiosperms we could identify a Rab21 only in Oryza sativa. It seems likely that these groups will get better support once more genome sequences become available.