Octopuses can edit their own RNA on the fly instead of waiting on DNA to evolve

In most animals, genetic information essentially flows one way: DNA determines RNA, and RNA determines proteins, with relatively minor tweaks along the way.

Octopuses, cuttlefish, and squid are the exception — they can extensively "re-edit" their RNA messages after they've already been copied from DNA, changing the structure of the resulting proteins without touching the underlying genetic code at all.

This ability is used especially heavily in nervous tissue, which may explain some of these animals' remarkable behavioral flexibility and adaptability — they can "retune" the proteins in their nervous system almost on the fly.

The price for that flexibility: heavy RNA editing appears to slow down the pace of ordinary DNA evolution in these animals — as if cephalopod evolution partly shifted onto an entirely different biological layer.