Sp70 (Fig. 26) and Hsp90 (Fig. 31) also contain several unique sequence signatures not found in any prokaryotic homologs. These signature provides evidence that all of the eukaryotes are derived from a single ancestor and that the postulated fusion event was unique.VOL. 62,PHYLOGENY OF PROKARYOTES AND EUKARYOTEScluding amitochondriate and aplastidic cells, received major gene contributions to the