First Gene-Edited Squid Is Clear As Glass

Tania Ghosh

3rd September, 2020




Cephalopods are the most intelligent, most mobile, and the largest of all mollusks.  These "brainy" invertebrates have evolved suckered tentacles, camera-like eyes, color-changing skin, and complex learning behavior. Their lengthy evolutionary history spans an impressive 500 million years. These creatures have interested the scientists for years and they have been researching on them for many years and now finally, they have achieved something that would remain as a mark in their research history- scientists have successfully genetically modified the squid.


Class:                                     Cephalopoda

Phylum:                                 Mollusca

Kingdom:                               Animalia

Scientific name:                    Cephalopoda

Higher classification:            Mollusca


Squid is a part of the class Cephalopoda. Scientists have tried a while now to work on Cephalopoda to know more about them Cephalopods seem plenty strange enough without scientists tinkering with their genes. These tentacled beings have huge, clever brains that look nothing like the human brain. They travel using jet propulsion and some can change their skin color in a flash to camouflage. All this oddness is exactly why some biologists want to better understand them. Cephalopod research has been hindered by the fact that there has been no way to manipulate squid or octopus genes. To change that fact, scientists have been growing several exotic cephalopod species — everything from flamboyant cuttlefish to pygmy octopuses — to figure out how to keep them going in captivity and alter their DNA.

Why is genetic modification Cephalopods really needed?

To explain in simple words, Genetic engineering, also called genetic modification or genetic manipulation, is the direct manipulation of an organism's genes using biotechnology. Scientists have finally made a breakthrough in trying to understand the Cephalopod genome and thus trying to modify it. Their success shows that cephalopods — which include squid and octopuses — can finally be studied using the same kind of genetic tools that have let scientists explore the biology of more familiar lab animals like mice and fruit flies. About three years ago, scientists at the Marine Biological Laboratory launched an initiative to develop a cephalopod whose gene could be manipulated. 

“Knocking Out” is the key

Researchers at the Marine Biological Laboratory used CRISPR-Cas9 genome editing to eliminate a gene in embryos of the squid Doryteuthis pealeii, which removed the pigment from their eye and skin cells, It was achieved their results by "knocking out" a gene responsible for pigmentation. Suppressing the function of a gene or inactivating it using gene manipulation methods in a DNA sequence of a gene is called a gene knockout process while gene knockin is the process of targeted insertion of an exogenous gene at a specific locus in the genome. his was done by injecting gene-altering materials into the fertilized egg, to disrupt a gene involved in coloring the squid's skin and eye cells. A gene knockout is a genetic technique in which one of an organism's genes is made inoperative and In molecular cloning and biology, a knock-in refers to a genetic engineering method that involves the one-for-one substitution of DNA sequence information in a genetic locus or the insertion of sequence information not found within the locus.



The result of the knockout was that The squid typically has dark eyes and an array of black and reddish-brown spots across their bodies while the genetically altered hatchlings have light pink or red eyes and almost no dark spots. Joshua Rosenthal, a researcher at the Marine Biological Laboratory in Woods Hole, Massachusetts said it provided an opportunity to compare them with humans and see what elements are in common, and what elements are unique. According to them, the biggest challenge was getting through a tough outer layer that surrounded the early squid embryo. But now that this experiment has been deemed successful, scientists are finding out how to add genes. They are also looking forward to studying their immune system.


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About the Author

Tania Ghosh, studies Biotechnology in St. Xavier's College Kolkata.