Scientists have created a transparent squid, allowing them to see inside while its still alive

A team of scientists has genetically engineered an albino transparent squid in the lab. The research team from the Marine Biological Laboratory (MBL) accomplished this incredible feat by using a strain of the hummingbird bobtail squid, known as Euprymna berryi.

This pioneering work, made available to the world on June 20th in the Current Biology journal, is an important scientific stride.

Creating a transparent squid – why is this so special?

Like something from science fiction, the team has created a nearly transparent creature. It is a living window to the nervous system of a cephalopod. This is a group of incredibly smart and mysterious sea creatures that includes squids, octopuses, and cuttlefish.

Plus, it’s the first time that scientists have been able to breed a genetically modified cephalopod over multiple generations. E. berryi now shows tremendous potential to become a model organism for studies focusing on the neurobiology of cephalopods, among other types of research.

MBL Senior Scientist Joshua Rosenthal, who co-directed the study with MBL Hibbitt Fellow Caroline Albertin, emphasized the importance of this development.

“There’s a whole lot of incredibly interesting biology surrounding cephalopods, unlike any other invertebrate,” Rosenthal said. “We now have a model cephalopod where we can interrogate biological function at much higher resolution than before.”

Why the scientists chose a cephalopod for their research

Cephalopods are fascinating creatures. They have far more complex nervous systems and behaviors than most invertebrates. They’re quick learners and can remember complex tasks. They can solve puzzles, use tools, and even learn just by watching others.

Cephalopods can change their color to blend with the environment in a blink of an eye. They interact with their environment using their arms and tentacles. According to another recent study by the MBL, these creatures can adjust to cold environments by tweaking their own RNA to a great extent.

Studying cephalopods is especially challenging

But studying cephalopods comes with challenges. In contrast to the extensive research on fruit flies and mice, the lack of a viable model organism has limited our understanding of cephalopods’ genetics.

However, this new study introduces E. berryi as an exciting candidate. It is easy to breed in a lab and can be genetically modified. This makes it a game-changer in cephalopod research.

Albertin, a co-author of the study, is optimistic about the possibilities. “The ability to directly and precisely test gene function in a model cephalopod is exciting because it makes it possible to study the features that make cephalopods special – and it will be an important tool for understanding many different aspects of their unique biology,” she said.

How the transparent squid was created

To create this transparent squid, the team deactivated two pigmentation enzymes in E. berryi’s genes using CRISPR-Cas9 genome editing. Then, Cris Niell from the University of Oregon, Eugene, and Ivan Soltesz from Stanford University examined the brain activity of the altered squid.

They did so by injecting a fluorescent dye into its optic lobe. This dye glows whenever it detects calcium. This is a substance that the brain releases when it becomes active.

The researchers then exposed the squid to various images. This activated its optic lobe and made the dye light up. This entire process was captured using a microscope. When they tried the same technique with a regular squid, its skin coloring obstructed a clear view of the dye.

Rosenthal explained the implications of this discovery, saying it “allows us to look at gene function and cephalopod brains in ways we couldn’t before.”

It opens up new avenues for researchers interested in studying how signals are relayed through cephalopod brains. They can now breed transparent squids and conduct similar experiments with the calcium-activated dye.

More discoveries made during the transparent squid experiment

The study also uncovered a new aspect of E. berryi’s biology. When they deactivated the first pigmentation gene, known as TDO, they expected to produce an albino squid.

This was a reasonable assumption because they had done so with a different squid species. In a 2020 study, they used the Doryteuthis species.

Surprisingly, the resulting E. berryi offspring still exhibited coloring. The scientists then discovered that a second enzyme called IDO was also generating pigment.

This was a function previously unknown in cephalopods. The reason behind E. berryi having two enzymes performing seemingly the same task remains a mystery for now.

The team hopes more scientists will join this research effort

The study’s leaders, Rosenthal, Albertin, and their team, have high hopes that other scientists will dive deeper into exploring the biology of E. berryi. They’re keen to see the albino squid shared with the wider research community. This will help unravel more of the seemingly endless mysteries of cephalopod biology.

Rosenthal expressed this sentiment clearly, “We want to see these animals shared with the research community. Cephalopods contain treasure troves of biological novelty. We want to see people using them to ask thought-provoking questions and come up with novel findings.”

In summary, the creation of this genetically engineered transparent squid, an albino strain of Euprymna berryi, is a significant leap forward in our understanding of cephalopods. This new version of the hummingbird bobtail squid will enable researchers to study these intriguing marine animals in ways we’ve never been able to before.

The research team’s hope is that this will stimulate further study and provoke thought-provoking questions. This will ultimately help us all better understand the incredible world of cephalopods.

More about squids

Squids are fascinating creatures and belong to the class Cephalopoda, which also includes octopuses, cuttlefish, and nautiluses. They are known for their distinct appearance.

Squids feature a soft body and elongated shape, a head surrounded by individual arms, and two longer tentacles.

Here’s what we know about squids:

Diversity and Size

There are approximately 300 known species of squids, ranging greatly in size. The smallest squid, the pygmy squid, can be less than an inch long, while the largest species, the colossal squid, can reach up to 46 feet in length. The vampire squid is another well-known species.

Anatomy

Squids have a soft, flexible body covered with a thin layer of skin. Underneath the skin, some species have a hard, feather-shaped structure called a pen. They have a sharp beak made of keratin, the same material as human nails, which they use to catch and kill their prey.

Arms and Tentacles

Squids have ten appendages: eight shorter arms and two longer tentacles. The tentacles are typically used to capture prey, which is then guided towards the mouth with the help of the shorter arms.

Ink

Most squids have an ink sac, which can eject a cloud of dark ink to confuse predators and facilitate a quick escape.

Movement

Squids are excellent swimmers. They move by jet propulsion – inhaling water into their mantle cavity and then forcefully expelling it through a funnel-like structure, propelling them backward.

Camouflage

Many squids have the ability to change their color and even their texture, thanks to special skin cells called chromatophores. This ability aids in camouflage, communication, and hunting.

Eyes

Squids have highly developed eyes similar to those of humans. This allows them to see well in both bright and dim conditions.

Intelligence

Squids are one of the most intelligent invertebrates. Some species exhibit complex behaviors such as problem-solving and tool use. This makes them able to better adapt to climate change.

Diet

Squids are carnivores and primarily feed on fish, crustaceans, and other squids. They are also prey for a variety of species including sharks, other squids, sea birds, and whales.

Reproduction

Squid reproduction involves the male squid depositing a sperm packet into the female’s body. The female then lays eggs, which she attaches to the seafloor or other substrates. Most squids die after reproducing.

Bioluminescence

Some squid species can produce light. This is a phenomenon known as bioluminescence, which they use for communication, attracting prey, or warding off predators.

Symbiosis

Some squid species, like the Hawaiian bobtail squid, have a symbiotic relationship with bioluminescent bacteria, which help them camouflage.

Please note that the information could vary greatly from one squid species to another. Not all squids possess the characteristics mentioned above. Also, scientists and researchers continue to make new discoveries about squids and their behavior.

More about CRISPR-Cas9 genome editing

CRISPR-Cas9, short for “Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR associated protein 9,” is a revolutionary tool in the field of genetics. The MBL scientists used this method to create the transparent squid.

Derived from a defense mechanism used by bacteria, it has been adapted to edit genomes — the complete set of genetic material present in a cell or organism. Here’s a breakdown of what we know about CRISPR-Cas9:

Mechanism – how the transparent squid was created

CRISPR-Cas9 works by utilizing a guide RNA (gRNA) to locate specific sequences of DNA within a genome. The guide RNA pairs up with the Cas9 protein, essentially guiding it to the correct location in the DNA.

Once at the right location, the Cas9 protein acts as a pair of ‘molecular scissors,’ cutting the DNA at the specified point. The cell’s own repair machinery fixes the break once the DNA is cut. This can introduce changes (mutations) in the sequence. Scientists can also provide a template for the repair process, thus precisely changing the genetic information.

Genome Editing

The power of CRISPR-Cas9 is that it allows scientists to add, remove, or alter specific parts of an organism’s DNA sequence, providing a level of precision, efficiency, and flexibility not previously available in genetic engineering. This has broad implications in fields like medicine, agriculture, and basic biological research.

Applications (other than creating transparent squid)

Some of the potential applications of CRISPR-Cas9 include treating genetic disorders, creating disease-resistant plants, combating pests, eliminating diseases spread by insects (like malaria), and much more. In research, it allows scientists to explore the function of different genes by creating organisms where those genes have been modified or removed.

Ethical Considerations

While the potential benefits of CRISPR-Cas9 are enormous, its use also raises important ethical considerations. For example, changes to the human germ line (i.e., eggs or sperm) could be passed onto future generations, raising concerns about unforeseen consequences. There’s also the potential for misuse, such as creating “designer babies” with specific genetic traits.

Future Prospects

As of my last update in September 2021, research is ongoing to refine the technique and minimize off-target effects (unintended modifications to the DNA), improve delivery methods, and address the ethical implications of genome editing.

In summary, CRISPR-Cas9 is a powerful tool that has revolutionized genetic research, offering the potential to tackle a range of problems, from genetic diseases to food security. However, it also raises important ethical questions that society must address.