A new paperwas published last week on a remarkable single-celled organism,Oxytricha trifallax, that has two nucleus’ and 16,000 chromosomes (recall that humans have 46). The organism uses one nucleus to store its active DNA and the other nucleus to store an archive of the genome. Amazingly, Oxytricha trifallax, disassembles the archived copy into a quarter-million pieces and then rapidly reassembles them into a new and improved version. This reassembly occurs at mating time as the organism and its mate exchange about half their genome. Read more