The number of genome copies in cells vary by species: most cells in the human body have two, whereas most bacteria have only one.
But not this particular bug: the Epulopiscium, a giant bacterium that lives in the intestines of unicorn fish, has up to 200,000 copies
of its genome!
Angert suspects that Epulopiscium ’s extravagant collection of genomes may be a way for it to reap the benefits of size without the drawbacks of starvation. She hypothesizes that the genomes are arrayed just beneath Epulopiscium ’s cell membrane. This arrangement means that the cell could respond to nutrients and other environmental molecules without waiting for them to diffuse throughout the cell. “If you waited for an environmental signal to get to you, relying solely on diffusion, it would take forever,” says Anger. “It would be really unreliable. This opens up that door of allowing the cell to get big and not allowing diffusion to limit its volume.”