Data from: Obligate endosymbiosis explains genome expansion during eukaryogenesis

The endosymbiosis of an alpha-proteobacterium that gave rise to
mitochondria was one of the key events in eukaryogenesis. One striking
outcome of eukaryogenesis was a much more complex cell with a large
genome. Despite the existence of many alternative hypotheses for this and
other patterns potentially related to endosymbiosis, a constructive
evolutionary model in which these hypotheses can be studied is still
lacking. Here, we present a new theoretical approach in which we focus on
the consequences rather than the causes of the mitochondrial
endosymbiosis. Using a constructive evolutionary model of cell-cycle
regulation, we find that genome expansion and genome size asymmetry arise
from emergent host–symbiont cell-cycle coordination. We also find that
holobionts with large host and small symbiont genomes perform best on long
timescales, and mimic the outcome of eukaryogenesis. By designing and
studying a constructive evolutionary model of obligate
endosymbiosis, we uncovered some of the forces that may drive the
patterns observed in nature. Our results provide a theoretical
foundation for patterns related to the mitochondrial
endosymbiosis, such as genome size asymmetry, and reveal
evolutionary outcomes that have not been considered so far, such
as cell-cycle coordination without direct communication.