A new discovery in genetics: some plants can replace recently mutated genes of theirs with the version of the gene that their ancestors had a few generations ago, apparently using a backup copy of the genetic code that they store in the form of RNA. The Washington Post describes:
The newly discovered phenomenon, which resembles the caching of early versions of a computer document for viewing later, allows plants to archive copies of genes from generations ago, long assumed to be lost forever.
The biologists who made the discovery suspect that there may be a similar process in humans. It's not clear to me how the plant "decides" when to switch the gene or how it manages to make the switch in all of the relevant cells. Since the scientists have not even found the RNA templates yet, we might have to wait a few years on the details.