So the energy savings accruing from endosymbiotic gene loss (just 5% of their genes) could easily support the evolution of a dynamic cytoskeleton, as indeed happened. Bear in mind, as well, that 100 endosymbionts is a conservative estimate. Some large amoebae have as many as 300,000 mitochondria. And gene loss went much further than a mere 5%. Mitochondria lost nearly all their genes.
