This is just plain weird:
Rosenthal, a neurobiologist at the Marine Biological Laboratory, was a grad student studying a specific protein in squid when he got an an inkling that some cephalopods might be different. Every time he analyzed that protein’s RNA sequence, it came out slightly different. He realized the RNA was occasionally substituting A’ for I’s, and wondered if squid might apply RNA editing to other proteins. Rosenthal, a grad student at the time, joined Tel Aviv University bioinformaticists Noa Liscovitch-Braur and Eli Eisenberg to find out.
In results published today, they report that the family of intelligent mollusks, which includes squid, octopuses and cuttlefish, feature thousands of RNA editing sites in their genes. Where the genetic material of humans, insects, and other multi-celled organisms read like a book, the squid genome reads more like a Mad Lib.
So why do these creatures engage in RNA editing when most others largely abandoned it? The answer seems to lie in some crazy double-stranded cloverleaves that form alongside editing sites in the RNA. That information is like a tag for RNA editing. When the scientists studied octopuses, squid, and cuttlefish, they found that these species had retained those vast swaths of genetic information at the expense of making the small changes that facilitate evolution. “Editing is important enough that they’re forgoing standard evolution,” Rosenthal says.
He hypothesizes that the development of a complex brain was worth that price. The researchers found many of the edited proteins in brain tissue, creating the elaborate dendrites and axons of the neurons and tuning the shape of the electrical signals that neurons pass. Perhaps RNA editing, adopted as a means of creating a more sophisticated brain, allowed these species to use tools, camouflage themselves, and communicate.
Yet more evidence that these bizarre creatures are actually aliens.
As usual, you can also use this squid post to talk about the security stories in the news that I haven’t covered.
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from Friday Squid Blogging: Squid Can Edit Their Own RNA