Conserving RNA editing sites may have come with an evolutionary trade-off, however. The result is a significant portion of the genome “That can’t really evolve fast,” Dr. Rosenthal said. Slower evolution is a “Big price to pay,” Dr. Eisenberg said, because DNA mutations are usually the source of new adaptive traits. It also suggests the greater ability to edit RNA “Must be worth it” in terms of natural selection, he said.
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.