A new study by marine biologists from the Marine Biological Laboratory, Woods Hall (USA) confirmed the observation from 2015 - squid are able to change fragments of their RNA when necessary. For other living things, this is unthinkable and akin to a severe and dangerous mutation, and these invertebrates have learned to bypass the imperfection of their genome in a very elegant way. The exact mechanism remains to be seen, but the very fact of such manipulation has been documented.
In the usual case, RNA begins to form during cell division, as a transport copy of the DNA sequence, fragment by fragment. But if in a person, for example, after leaving the nucleus, such RNA does not change and delivers its genetic load intact, then in squid it enters the axon. And there, under the influence of a number of factors, the process of restructuring of this RNA is launched, and a very large-scale one.
Scientists do not know why squid need such a strange mechanism. There is a version that they decided to take evolution into their own hands, and therefore do not rely on random mutations and do not wait until their body begins to adapt to the new reality. They run a guided editing package to immediately rewrite RNA and assemble completely different proteins from them. Those that the body needs to survive right now.
At the same time, the old, "fundamental" DNA code does not disappear anywhere and remains as a standard. For comparison and control in future replications. Squid, octopus, and cuttlefish use RNA editing to diversify proteins produced in the nervous system. Perhaps this explains the unprecedented level of intelligence of this trinity in comparison with other invertebrates.