Differential gene transfers and gene duplications in primary and secondary endosymbioses

Abstract

Background: Most genes introduced into phototrophic eukaryotes during the process of endosymbiosis are either lost or relocated into the host nuclear genome. In contrast, groEL homologues are found in different genome compartments among phototrophic eukaryotes. Comparative sequence analyses of recently available genome data, have allowed us to reconstruct the evolutionary history of these genes and propose a hypothesis that explains the unusual genome distribution of groEL homologues. Results: Our analyses indicate that while two distinct groEL genes were introduced into eukaryotes by a progenitor of plastids, these particular homologues have not been maintained in all evolutionary lineages...