Figure 3. Model of transfer of myxococcal genes to eukaryotes.

(1) A hydrogen-consuming methanogenic archaeon established symbiosis with the hydrogen-producing mitochondrial ancestor. Previously, a fatty acid degrading myxococcal species transferred genes to the mitochondrial ancestor before the endosymbiotic event. (2) The methanogenic archaeon engulfed the symbiont that gave rise to the mitochondrion. Over time, genes were transferred to the eukaryotic nuclear genome via endosymbiotic gene transfer. Proteins with myxococcal, mitochondrial and archaeal ancestries are depicted in green, blue and yellow boxes, respectively.