Octopus Genetics Just Got A Whole Lot Weirder

Featured Image Credit: NATIONAL AQUARIUM OF NEW ZEALAND
By: Jessica Kittel

In case you weren’t aware, coleoid cephalopods (octopus, squids, and cuttlefish) are pretty cool. Exhibit A: giant squids can grow to be up to 43 feet long and were likely the inspiration for various well-known sea monster tales. Exhibit B: cuttlefish are known to put on amazing camouflaging color change performances. Exhibit C: the octopus. The amazingly intelligent mollusk that is the Harry Houdinis of the underwater world. After all that how could they possibly get cooler?  Thanks to some crazy newly released research involving RNA editing.

According to new research published in the journal Cell, coleoids frequently edit their RNA in order to adapt to their surrounding environment.

That probably doesn’t sound particularly impressive at first glance, however, don’t get confused here. RNA (ribonucleic acid) is not the same thing as DNA (deoxyribonucleic acid). It’s well known that DNA can be altered in the form of a genetic mutation and then passed down from parent to offspring. That’s how evolution occurs. However, that’s not what’s happening here.  

Just a brief reminder how the whole genetics game works: genes encode instructions via DNA, which is inherited and holds all the information necessary to make, let’s say, an orange cat. While the DNA has all the info, it needs RNA in order to put this information into action. The information in the DNA is transcribed into RNA, which can then go make proteins to build said orange cat.  

 

However, sometimes, the RNA will get altered after being transcribed from DNA but before being used to make proteins. This is known as RNA editing and can be used to change the constitution of the protein that is being made without having to change any fundamental DNA information. RNA editing has been known to get a little “messy”  however and therefore seems to have been pushed to the back burner in most animals in favor of good old-fashioned genetic mutation.  

Coleoids seem to have missed the memo. Scientists have discovered that the common squid has edited more than 60 percent of the RNA found within their nervous system meaning they have basically changed the physiology of their brain in response to their environment, likely in response to ocean temperature changes. Scientists hypothesize that the reason these coleoids are so smart is that they rely on RNA editing to keep their brain in prime condition for their environment.  

However, everything has a price. In order to be able to edit their RNA, coleoids have been evolving extremely slowly genetically. So in order to be able to adapt in real time, it would appear that they have had to mostly forgo the ability to pass on beneficial adaptations they have gained to their offspring.  

However, in a world with such rapidly changing conditions, this ability to pull a quick switch and produce proteins that work better in, say, warming ocean temperatures could prove to be their saving grace.