Becky sez, "According to a report in the journal Nature, one plant appears able to revert to genetic code that doesn't contain a mutation that its parents had, i.e., it appears to have some kind of backup. The authors of the paper theorize that the backup may reside in molecule RNA somewhere, and that stress may trigger the reversion. If this turns out to be the case in other species–like, oh, say, humans, and the lead author suggests that could be so–not only will we have to rewrite the genetics textbooks, but locating the RNA backups and/or learning how to trigger them might be a new route to cure of diseases with a genetic component."
(Thanks, Becky!)