Exosymbiogenetic (Coevolutionary) Model of Eukaryogenesis (hypothesis)

Abstract

According to the now popular endosymbiogenetic theory, eukaryotes evolved from a fusion of archaeal and bacterial cells. The resulting superorganism became the first eukaryocyte 1, 2.

Various pairs of symbionts have been proposed (3, 4, 5, 6,7). Genomic data confirm that most eukaryotic proteins are of either archaeal or bacterial origin. These proteins have few common characteristics, most importantly, a single source has not been found for them. Rather, they come stem from many different bacteria through the transfer of individual groups of genes, rather than through endosymbiosis and fusion of whole cells. To date, only a variant of the endosymbiotic hypothesis is being considered, in which the third partner might be a large virus 1, 2.