Saturday, March 9, 2019

Nature has some truly weird critters . . .

I was astonished to learn that octopus and squid are different from any other critters in the sea - or on land - as far as their genetics are concerned.

In a surprising twist, in April 2017 scientists discovered that octopuses, along with some squid and cuttlefish species, routinely edit their RNA (ribonucleic acid) sequences to adapt to their environment.

This is weird because that's really not how adaptations usually happen in multicellular animals. When an organism changes in some fundamental way, it typically starts with a genetic mutation - a change to the DNA.

Those genetic changes are then translated into action by DNA's molecular sidekick, RNA. You can think of DNA instructions as a recipe, while RNA is the chef that orchestrates the cooking in the kitchen of each cell, producing necessary proteins that keep the whole organism going.

But RNA doesn't just blindly execute instructions - occasionally it improvises with some of the ingredients, changing which proteins are produced in the cell in a rare process called RNA editing.

When such an edit happens, it can change how the proteins work, allowing the organism to fine-tune its genetic information without actually undergoing any genetic mutations. But most organisms don't really bother with this method, as it's messy and causes problems more often that solving them.

"The consensus among folks who study such things is Mother Nature gave RNA editing a try, found it wanting, and largely abandoned it," Anna Vlasits reported for Wired.

But it looks like cephalopods didn't get the memo.

In 2015, researchers discovered that the common squid has edited more than 60 percent of RNA in its nervous system. Those edits essentially changed its brain physiology, presumably to adapt to various temperature conditions in the ocean.

The team returned in 2017 with an even more startling finding - at least two species of octopus and one cuttlefish do the same thing on a regular basis.

. . .

It's true that coleoid cephalopods are exceptionally intelligent. There are countless riveting octopus escape artist stories out there, not to mention evidence of tool use, and that one eight-armed guy at a New Zealand aquarium who learned to photograph people. (Yes, really.)

So it's certainly a compelling hypothesis that octopus smarts might come from their unconventionally high reliance on RNA edits to keep the brain going.

There's more at the link.

Hmmm . . . if we could figure out how to switch that RNA editing function on and off, perhaps we could develop calamari that seasons itself?



B said...

In reality cepholopods are devolved aliens who crashed here eons ago when their spacecraft was struck by a meteor while decelerating to orbit the sun for fuel.

Seriously...we were the only compatible planet for them.

Paul, Dammit! said...

I've seen RNA editing come up as a possible mechanism for a few things in macrovertebrates, but the definitive links never seem to show up. Morphological changes to environmental conditions, like the barrel chest that develops among mountain folk, which can be tied to when in their adolescent stage they spend time at high altitude, or the rate of production of enzymes that facilitate cold-weather adaptation.

There IS a tenuous link between RNA editing and chloride cell development in salmon during the smoltification process, when they become salt-water tolerant but before they become salt-water adapted.

Like so many esoteric pursuits, the information is out there, but the money, time and space to explore it is limited. Part of the reason why I quit being a neurophysiology nerd researcher in favor of being a commercial fisherman as a yoot.