Squid RNA Editing Creates Vast Protein Diversity, Study Finds

Potential variants outnumber atoms in the universe by hundreds of orders of magnitude

By LineZotpaper AI staff

Published24 October 2026

Read Time2 min

Illustration: Squid RNA Editing Creates Vast Protein Diversity, Study Finds

Scientists at the University of California, San Francisco have found that the longfin inshore squid employs RNA editing on an unprecedented scale, theoretically producing a staggeringly vast array of protein variants. The study, published in the journal Cell, details how these cephalopods modify their genetic instructions without altering their DNA, offering new insights into their alien-like biology.

Cephalopods like squid, octopus, and cuttlefish have long fascinated researchers with their complex nervous systems and remarkable adaptability. A new study from the University of California, San Francisco (UCSF), published in the journal Cell, helps explain how they achieve this flexibility.

The study, led by UCSF researcher Jack Moen, examined the proteome of the longfin inshore squid (Doryteuthis pealeii) to understand the impact of ADAR-mediated RNA editing. This process allows cells to change the RNA instructions for making proteins without altering the underlying DNA blueprint.

While humans and other animals use this process sparingly, coleoid cephalopods perform it with unmatched vigor. "By editing the RNA instructions used to make proteins, these animals can generate proteins with different properties, all without changing their DNA," Moen told ScienceAlert.

To discover the effects, the researchers explored nearly 8,000 editing sites across more than 2,000 different proteins in the squid's optic lobe and gills. They found profound effects on protein activity, stability, and localization. The changes even influence the health of organelles like mitochondria. "We found effects on protein activity, stability, localization, and even how they interact with other proteins. The downstream effects even go so far as to regulate organelle health," Moen said.

The scale of the potential protein diversity is staggering. Based on the sites identified, the number of possible edited protein variants is theoretically around 10²⁴⁸. This is well over one hundred orders of magnitude greater than the total number of atoms in the universe. The study also identified 5,000 short proteins not previously found in standard databases.

"They describe an enormous potential diversity," Moen said of the numbers. How much of it the animals actually produce remains unknown.

Analysis

Why This Matters

The finding fundamentally expands our understanding of gene expression and evolution, showing a creature can massively diversify its proteins without changing its DNA.
It helps explain the intellectual and physical capabilities of cephalopods, offering insights into alternative evolutionary paths for complex nervous systems.
The mechanisms studied could eventually inspire new biotechnological approaches to protein engineering or synthetic biology.

Background

ADAR-mediated RNA editing is a known biological process where cells modify RNA molecules. In most animals, it is a relatively minor regulatory tool. This research shows that in coleoid cephalopods (squid, octopus, cuttlefish), this process is extraordinarily active, potentially fueling their advanced evolution. The study provides the most detailed look yet at the functional consequences of this editing, showing it directly alters protein structures and functions.

What to Watch

Future research will seek to understand why this unique ADAR activity is so dominant in cephalopods and what evolutionary path led to it.
A key question remains how much of the theoretical protein diversity (10²⁴⁸ variants) is actually used in real biological contexts by the squid.
The findings could spur investigation into whether similar mechanisms exist or can be engineered in other organisms for medical or industrial applications.

Sources

Squid Are Even More Alien-Like Than We Thought, With an Unmatched Ability to Change Genetic Expression · ScienceAlert

Checked

10 claims in this story checked against 1 source: 6 supported.

Show each claim

Partly supportedThe headline says squid RNA editing creates vast protein diversity.ScienceAlert: “The theoretical possibilities are overwhelming and beyond astronomical, with more protein variants than all the stars, planets, and super-alcohol clouds in the Universe combined.”
Partly supportedPotential protein variants outnumber the universe’s atoms by hundreds of orders of magnitude.ScienceAlert: “That is well over 100 orders of magnitude greater than all the atoms in the Universe.”
Not in the sourcesThe study was led by UCSF researcher Jack Moen.ScienceAlert: ““We found effects on protein activity, stability, localization, and even how they interact with other proteins. The downstream effects even go so far as to regulate organelle health,” first author Jack Moen, a cellular and molecular scientist at UCSF, told ScienceAlert.”
Partly supportedHumans and other animals use RNA editing sparingly.ScienceAlert: “Humans and other animals constantly undergo an ephemeral, reversible transcriptomic remixing through what’s known as ‘adenosine deaminase acting on RNA’ or ADAR-mediated RNA editing.”
SupportedMoen said, “By editing the RNA instructions used to make proteins, these animals can generate proteins with different properties, all without changing their DNA.”ScienceAlert: ““By editing the RNA instructions used to make proteins, these animals can generate proteins with different properties, all without changing their DNA.””
SupportedMoen said, “We found effects on protein activity, stability, localization, and even how they interact with other proteins. The downstream effects even go so far as to regulate organelle health.”ScienceAlert: ““We found effects on protein activity, stability, localization, and even how they interact with other proteins. The downstream effects even go so far as to regulate organelle health,””
SupportedResearchers explored nearly 8,000 editing sites across more than 2,000 proteins in the squid’s optic lobe and gills.ScienceAlert: “To discover extra effects, they explored nearly 8,000 sites where proteins were edited across more than 2,000 different proteins in the squid optic lobe and the gills.”
SupportedThe theoretical number of possible edited protein variants is around 10²⁴⁸.ScienceAlert: ““If we look at all of the sites identified in the RNA sequencing data, it brings the theoretical estimate closer to 10²⁴⁸,” Moen told ScienceAlert.”
SupportedThe study identified 5,000 short proteins not previously found in standard databases.ScienceAlert: ““Another result that struck us was the potential to create new protein sequences,” Moen adds, as they identified 5,000 short proteins that were not in the reference squid proteome or in the gold-standard Swiss-Prot database of 14,000 organisms.”
SupportedMoen said, “They describe an enormous potential diversity.”ScienceAlert: ““They describe an enormous potential diversity,” Moen said.”

Correction

24 October 2026An earlier version of this story incorrectly presented ScienceAlert's narration about how much protein diversity the animals actually produce as a direct quote from Jack Moen.