
Octopus and Squid Evolution Is Weird - mooreds
https://www.sciencealert.com/it-s-official-octopus-and-squid-evolution-is-weirder-than-we-could-have-ever-imagined
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rwmj
Is there a better article we could link to? _" Mother Nature gave RNA editing
a try, found it wanting, and largely abandoned it" ... "it looks like
cephalopods didn't get the memo"_ What is that supposed to mean?

The Wired article is slightly better:
[https://www.wired.com/2017/04/cephalopod-gene-
editing/](https://www.wired.com/2017/04/cephalopod-gene-editing/)

The original Cell article uses lots of jargon:
[https://www.cell.com/cell/fulltext/S0092-8674(17)30344-6](https://www.cell.com/cell/fulltext/S0092-8674\(17\)30344-6)

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masklinn
> Is there a better article we could link to? "Mother Nature gave RNA editing
> a try, found it wanting, and largely abandoned it" ... "it looks like
> cephalopods didn't get the memo" What is that supposed to mean?

The transcription process is DNA -> RNA -> Protein. In the vast majority of
living systems mutations happen at the DNA and DNA -> RNA transcription
levels, but once you've got RNA it's a relatively straight path to proteins.
It's possible to edit RNA but quite unstable and fiddly, so most living
systems only make limited use of it, and their "RNA edition pipeline" is quite
fixed and limited.

coleoids however apparently edit RNA to an extent unknown of elsewhere,
seemingly trading that off for DNA-based evolution: for RNA edition to keep
working properly, the source RNA has to be pretty stable otherwise you're
building on quicksand, that means DNA mutations will break RNA editions and
thus probably viability.

Think of it this way: DNA is source code, RNA is compiler IR and proteins are
object code.

Most species edit the source code, they can have optimisation passes on the IR
(RNA edition) but it can't be too extensive because the pattern matching will
easily break if the source changes too much, and that might break the software
entirely.

However coleoids do most or all their coding as optimisation passes working on
the IR. And the more these IR passes do, the more they rely on the source code
not changing because all of a sudden your "optimisation" passes don't work
anymore and it turns out they're absolutely critical to the software working.

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ape4
The octopus is editing its RNA to deal with different temperatures. Sounds
like an overly dramatic way of doing it. Maybe instead of using an `#ifdef
TEMP_THRESHOLD 15` they should have used a `int temp_threshold = 15;`

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astazangasta
While this is cool, there is weird shit in every clade. Mammals have CpG
methylation. We are also cool.

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m463
It should be noted that ethylation of humans is also cool, because it
frequently leads to combination with external DNA.

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ci5er
I am ashamed that* I almost googled ethylation, before I got that.

* He says, fully ethylated... But unfortunately not tonight recombinated.

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sgt101
It would be great if they test the memory hypothesis. Perhaps by trying to
catch the line of RNA changes that allow a problem to be remembered from
generation to generation?

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benj111
Octopi and squids are just weird.

So does this mean that they're basically the Lisp of the animal world.

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bjelkeman-again
I think of octopus as the closest to a truly alien intelligence we will be
able to get until we can travel to the stars.

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wanderr
I just said the same thing to a friend yesterday. They are truly fascinating.

