Coleoid cephalopods, a group encompassing octopuses, squid and cuttlefish, are the most intelligent invertebrates: Octopuses can open jars, squid communicate with their own Morse code and cuttlefish start learning to identify prey when they’re just embryos.

In fact, coleoids are the only “animal lineage that has really achieved behavioral sophistication” other than vertebrates, said Joshua Rosenthal, a senior scientist at the Marine Biological Laboratory in Woods Hole, Mass. This sophistication could be related to a quirk in how their genes work, according to new research from Dr. Rosenthal and Eli Eisenberg, a biophysicist at Tel Aviv University.

In the journal Cell on Thursday, the scientists reported that octopuses, squid and cuttlefish make extensive use of RNA editing, a genetic process thought to have little functional significance in most other animals, to diversify proteins in their nervous system. And natural selection seems to have favored RNA editing in coleoids, even though it potentially slows the DNA-based evolution that typically helps organisms acquire beneficial adaptations over time.

He and Dr. Rosenthal found that RNA editing is enriched in coleoids’ nervous tissues, so they suspect it contributes to these animals’ behavioral complexity, possibly by allowing for dynamic control over proteins in response to different environmental conditions or tasks. Previously, Dr. Rosenthal showed that RNA editing might help octopuses rapidly adapt to temperature changes.

Other organisms use all sorts of different methods to modify their RNA, but the possibility that coleoids use extensive RNA editing to flexibly manipulate their nervous system is “extraordinary,” said Kazuko Nishikura, a professor at the Wistar Institute, a nonprofit biomedical research institute in Philadelphia, who was not involved in the study.

“We may learn a lot from squid and octopus brains,” she said.

https://www.nytimes.com/2017/04/06/science/octopus-squid-intelligence-rna-editing.html