Every living thing has DNA which defines its chemical repertoire. But what to make when and where and how much? This is epigenetics, decided on the fly in a way that adapts the organism to the current situation.
Octopuses go a step further. They edit their DNA on the way to translation (when it is in the form of messenger RNA). It’s normal to choose which genes to express on the fly. But Octopuses can also change their own genes on the fly.
Read more by Ed Yong in The Atlantic.