Slippery goal: Using octopus as lab animal
WOODS HOLE, Massachusetts: The cuttlefish, as small and testy as a hand grenade, was refusing to cooperate.
Close relatives of squids, flamboyant cuttlefish are camouflage experts that can dramatically alter their skin textures and colours. Biologists who study this feature at the Marine Biological Laboratory put cuttlefish into a circular tank filled with black and white pebbles. Most of the many-armed subjects hunker down, become black and white, and fade into the background.
Not this one. It swam laps, ignoring the pebbles, and curled two arms upward like tusks, which it turned cranberry-red. The cuttlefish squirted a little plume of ink. The supervising researcher sighed. So went another afternoon at the seaside science hub.
In a cavernous laboratory here, scientists are raising thousands of octopuses, cuttlefish and their kin as part of the Cephalopod Program, a three-year-old initiative to transform these sea creatures into the next lab animals. Cephalopods ooze scientific appeal: They have complex bodies, unusual genetics, impressive spatial skills and intelligent minds. Yet the animals can be reluctant to breed, hard to raise and difficult to keep from escaping their tanks. Few laboratory protocols - and, in the United States, no legal regulations - offer guidance.
Cephalopods “are considered the most alien form on the planet, the only invertebrate capable of higher-order cognitive tasks,” said squid expert Erica Vidal, a marine scientist at the Federal University of Parana in Brazil and a former president of the research organisation the Cephalopod International Advisory Council. She said the research community is small, with about 500 scientists worldwide, but she estimated the community increased by about 30 per cent between 2012 and 2018.
In January, the Marine Biological Laboratory announced it was the first facility to raise multiple generations of pygmy zebra octopuses.
“This is the first effort to go make a genetically tractable model,” meaning a species with catalogued and manipulable genes, said neurobiologist Joshua Rosenthal, who leads the laboratory’s initiative. He wears a surfer-dude grin while describing the intricacies of cephalopod genetics. As a rule, cells precisely turn DNA sequences into RNA and transform this RNA into proteins. But cephalopods use enzymes to edit genetic information in RNA, the only animals known to so frequently subvert this basic process of molecular biology.
Like a cook who changes a recipe to taste, cephalopod cells tweak this RNA. The animals most frequently rewrite RNA codes to make new proteins in their neurons. Rosenthal predicts RNA editing could be adapted for human therapeutic purposes, such as temporarily shutting off a cell’s ability to signal pain.
Cephalopods are “fantastically bizarre,” said Caroline Albertin, a developmental biologist at the Woods Hole facility. In 2009, Albertin was interviewing with neurobiologist Clifton Ragsdale for a graduate student position at the University of Chicago. Ragsdale gave her a tour of his laboratory. Inside a massive tank sat a single octopus egg. Inside that was an embryo. Within its transparent eggshell, the embryonic octopus began to transform, rippling with colours.
“And as we were watching, it hatched out, changed colours, inked and swam away,” Albertin said. She was hooked. Years later, Albertin and Ragsdale sequenced the first octopus genome - of the same species, the California twospot octopus, the young biologist watched hatch.
“They have these amazing behaviours,” Albertin said. “They’ve got these beautiful, weird body plans.” Three hearts, pumping bluish blood, beat within an octopus. A doughnut-shaped brain encircles its oesophagus.
Some cephalopods can break free from their tanks, such as an octopus named Inky that crawled out of a New Zealand aquarium in 2016 and followed a drainpipe to the Pacific Ocean. In 2009, biologists reported that wild octopuses near Indonesia carry discarded coconut shells, which the animals use as transportable shelters. This, depending on the animal behaviour expert you ask, counts as tool use.
“They know when you’re not looking at them anymore,” said Brett Grasse, who manages the cephalopods at the Marine Biological Laboratory.
“Octopuses are so remarkable that it would be good to learn more about them,” said the philosopher Godfrey-Smith, one of Franks’ co-authors on the
Octopuses are so remarkable that it would be good to learn more about them. A lot of embryological and developmental work can be done in a way that is not especially inhumane. – Godfrey-Smith, researcher
octopus farming paper. “A lot of embryological and developmental work can be done in a way that is not especially inhumane. And, of course, it is possible also to do behavioural experiments that do not involve surgery or other invasive procedures at all.” Hanlon’s camouflage studies at the Marine Biological Laboratory, which use the black-and-white pebble tank, require nothing more intrusive than a video camera.
Godfrey-Smith was afraid of the possibility for “cruel” experiments, however. “It is hard to do neuroscience on complex organisms without harming them.” — Washington Post.