A groundbreaking new study used CRISPR to achieve the first gene knockout in a cephalopod species using the squid Doryteuthis pealeii, a big name in the world of scientific research. The milestone removed a pigmentation gene in squid embryos, producing see-through offspring and has since been published in the journal Current Biology.
The achievement took place at the Marine Biological Laboratory (MBL), an affiliate of the University of Chicago, led by MBL Senior Scientist Joshua Rosenthal and MBL Whitman Scientist Karen Crawford. They used CRISPR-Cas9 genome editing to knock out a pigmentation gene in longfin inshore squid embryos, which removed color from the eye and in the squids’ skin cells, called chromatophores.
"CRISPR-Cas9 worked really well in Doryteuthis; it was surprisingly efficient," said Rosenthal in a statement. "This is a critical first step toward the ability to knock out – and knock in – genes in cephalopods to address a host of biological questions.”
The only complication came in trying to get the CRISPR-Cas9 system inside the squid embryo as they’re protected by a tough outer layer. To overcome this the team rustled up some special micro-scissors that could clip the egg’s surface and slip the reagents through with a quartz needle. Not something you’d find in your average haberdashery.
Longfin inshore squid are an exceptionally important research organism in biology having been widely used in research for nearly a century. Cephalopods in general are a source of much excitement for scientists owing to their unique talents, from camouflage to the ability to extensively recode their own genetic information. Understanding what enables such skills opens many doors for a range of fields, from medicine, robotics, novel materials, and artificial intelligence.
For all their talents, however, these animals aren’t an ideal species as a genetic research organism. With great power comes great body mass, and longfin inshore squid take up an awful lot of tank space in labs. With this in mind, the team’s next goal is to recreate the gene knockout in the smaller cephalopod species Euprymna berryi, appropriately known as the hummingbird bobtail squid.
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