Symbiosis in eukaryotic evolution

Molecular phylogeny, comparative genomics and the exploration of microbial diversity and interactions in the environment converge to support the symbiotic origin of the eukaryotic cell. The first eukaryotes arose by symbiosis of one archaeon and one or several bacteria along a non-fully-elucidated process. Eukaryotic photosynthesis arose by the endosymbiosis of a cyanobacterium in a heterotrophic host and subsequently spread to other eukaryotes via secondary algal endosymbioses.159