Like other ciliates, O. trifallax has two nuclei: a micronucleus, which contains its entire genome, and a macronucleus, which houses an edited version of the genetic material that's used to run the ship. What's extraordinary about O. trifallax is the degree to which its macronuclear genetic material has been rearranged. Derived afresh each generation from the micronuclear genetic material through an elaborate process that involves chopping up chromosomes, rearranging genes, deleting virtually all of the noncoding DNA, making multiple copies of the various bits, and capping them with telomeres, it ends up with tens of thousands of “nanochromosomes” that then serve as the templates for producing all the proteins that O. trifallax needs to conduct the day-to-day business of being alive.
Tantalizing Glimpses into a Fragmented Genome
PLoS Biol 11(1): e1001470.