Cephalopods edit their RNA

Brian G Turner

Fantasist & Futurist
Staff member
Nov 23, 2002
Squid and octopi are more alien than we thought:
Squid and octopus can edit and direct their own brain genes


Octopuses and squid have confirmed their reputation as Earth-bound “aliens” with the discovery that they can edit their own genetic instructions.

Unlike other animals, cephalopods – the family that includes octopuses, squid and cuttlefish – do not obey the commands of their DNA to the letter.

Instead, they sometimes interfere with the code as it is being carried by a molecular “messenger”. This has the effect of diversifying the proteins their cells can produce, leading to some interesting variations.

The system may have produced a special kind of evolution based on RNA editing rather than DNA mutations and could be responsible for the complex behaviour and high intelligence seen in cephalopods, some scientists believe.

RNA, a close cousin of DNA, is used to transfer software-like instructions from the genes to protein-making machinery in cells.

Scientists discovered that more than 60 per cent of RNA transcripts in the squid brain are re-coded by editing. In other animals, ranging from fruit flies to humans, such re-coding events only occur a fraction of 1 per cent of the time.

Similar high levels of RNA editing were identified in three other “smart” cephalopod species, two octopuses and one cuttlefish.

The mechanics of cephalopod RNA editing are still being investigated.
I watched a documentary once that was talking about evolution if you took man out of the equation. A common consensus among biologists was that squids would be a likely option to become a new dominant species, their "legs" allowing for motion on land as well as in water.

I found the idea of highly intelligent squid both interesting and alarming.

Cephalopods are scary, and probably aliens.
The article goes on to say:
The mechanics of cephalopod RNA editing are still being investigated. “When do they turn it on, and under what environmental influences? It could be something as simple as temperature changes or as complicated as experience, a form of memory,” says Joshua Rosenthal, lead author from the Marine Biological Laboratory at Woods Hole, US.
That this happens at all is perhaps the least surprising thing, given that it apparently happens with all of us (albeit to a tiny degree), because no biological mechanism (including RNA production) is going to be perfect. Far more interesting, to me, are:
  • how widespread within an individual are the changes (i.e. is all the RNA in an individual potentially put in "edit" mode)?
  • are the changes to the RNA the same throughout an individual, i.e. is this unlike DNA mutations, so that the RNA changes are random (which begs the question of the effect that they may have: with mutation of the DNA in a germ cell, it's clear how this effects the whole DNA of the resulting organism; it's far less clear how a random change in a specific piece of RNA in a single cell, produced for a specific instance of, say, protein production, can have widespread effects in the organism)?
  • are the changes, once set in motion, the same in closely related members of the same species (i.e. is the process not at all random, but in some way controlled during the production of the RNA in each cell)?
  • can the changes be reversed (i.e. the "editing" stops when the conditions change) or are they permanent?

The whole thing is, to quote our favourite half-Vulcan, fascinating.
Truly. We hope they don't go into Cthuhlu mode. Can they be reasoned with, do they know they are doing this or is it fully automatic?

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