Gene Editing Comes Naturally to Squids and Octopuses

Fagjun | Published 2017-04-09 08:06

Just as we thought squids and octopuses were weird enough, scientists have now found that these marine creatures do a significant amount of gene editing on themselves as well.

Genes are basically the basic ingredients that make up what we are. Once born, all living things—well, most of us, anyway—can't change anything about these ingredients. However, octopuses, squids, and other cephalopods aren't as rigidly bound by their genes.

If you've seen the film “Arrival”, you may have noticed that the aliens in the film look a lot like humongous octopuses. There's definitely something...odd, even alien-like about these marine animals. In fact, scientists have even compared octopus genome to that of aliens.

A new discovery may cast more doubt if octopuses and other similar marine animals are indeed of this Earth. (They are. They're just weirder than most of us.)

Gene Editing, the Natural Way

One of the appendages of the octopus-like aliens in "Arrival" (2016)
[© Paramount Pictures]

When living things need to adapt to our environments, we usually rely on mutations in our DNA. Cephalopods, however, don't want to wait for that to happen. They instead make changes to their RNA to be able to adapt to their environment.

RNA, or ribonucleic acid, functions as a sort of messenger. It facilitates the flow of genetic information from our DNA throughout each of our cells. While cephalopods edit their RNA, their DNA itself remains the same. When they procreate, they pass on their DNA and not the edits they made. The edits work only for the individual that made them, and won't affect future generations of the species. Though cephalopods aren't the only living things who make changes to their RNA, they do it more extensively.

Editing RNA is also so rare that it's not in the “Central Dogma” of genetics.

According to the researchers that made the discovery, cephalopods have DNA with a slower rate of mutation compared to that of other species. This rate of mutation is apparently important to editing RNA.

As a result of gene editing, cephalopods produce new proteins and enzymes and thus gain new abilities. They're creating new proteins that their DNA does not actually code for. “With these cephalopods, this is not the exception,” says Eli Eisenberg, one of the researchers. “This is the rule. The rule is that most proteins are being edited.”

Why Do Cephalopods Edit Their Genes?

Octopuses in particular are one of the most intelligent animals on Earth. They can learn and retain information through observation, escape from traps, and use tools for protection. The researchers now wonder if these abilities are the result of gene editing. Mostly, though, octopuses seem to edit their RNA in order to adapt to changes in the temperature. The same edits happen in squids as well.

At first, the researchers weren't quite able to believe their findings. After all, the findings are indeed surprising and, well, a little out there. However, their analyses showed that gene editing is common in two species of octopus, one species of squid, and the common cuttlefish. These species fall under the coleoid subclass of cephalopods, which exhibit remarkable social and hunting behaviors.

As of now, researchers need to investigate gene editing more to understand its mechanics. They still don't know under which circumstances or environmental influences cephalopods employ gene editing. With more observations, we may know sooner or later.

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