Rollback your DNA

Found this at The Scientist. Seems even after DNA has been changed, planst can revert back to the DNA of their ancestors:

She had found that a mutant Arabidopsis plant could "fix itself" back to the wild-type and take on the genetics of its grandparents. That seemed to contradict the laws of Mendelian inheritance.

It all sounds very similar to current Windows software that saves a snapshot of your system, and lets you rollback to those settings if something bad happens - like catching a computer virus

According to this theory, somewhere in the plant cells exists an RNA copy of ancestral DNA, sequences of which the plants can tap and randomly substitute into their own DNA, accounting for the reversion. Of course, Gregor Mendel's law of segregation states that offspring inherit two alleles for one trait, one allele from each parent. That means there's a linear relationship of inheritance between parent and child, and each offspring's alleles can only come directly from their parents' alleles. A non-Mendelian system of inheritance has "enormous implications," says Lolle, with the potential to unseat nearly two centuries of assumptions in genetic research.

...Researchers speculate this mechanism evolved as a way to evade viruses that often create double-stranded RNA as they spread in the host system.