Researchers have typically relied on animal models to learn more about biology. As research advanced and laboratory tools became more powerful, we came to know a lot about those lab organisms, like fruit flies, mice, and rats, and scientists gained the ability to manipulate their physiology in many ways. But those organisms are not ideal for every study. There are some animals that could offer incredible insight into biology, health, and disease, but we’ve lacked the tools and the knowledge to use them.
CRISPR, outlined in the video above, has changed the research landscape, however. Adapted from an immune defense system used by bacteria, it has nearly unlimited potential to alter the genomes of myriad organisms. Researchers are beginning to apply CRISPR to some unusual creatures in an effort to bring them into the lab.
“We finally are ready to start expanding what we call a model organism,” Tessa Montague, a molecular biologist at Columbia University in New York City, told Nature.
Montague has been studying species known for their amazing abilities to change the texture and color of their bodies, the Hawaiian bobtail squid and the dwarf cuttlefish. These cephalopods can produce patterning in their skin that reflects what they observe. Researchers want to know how sensory information is processed in cephalopod brains, but electrodes and sensors are tough to place in these boneless animals.
For the first time, scientists were able to inject CRISPR reagents into the cephalopods in Montague’s lab. Their next goal is to alter neurons in the animals so they will emit light when they are activated.
In recent work by the lab of Daniel Kronauer at Rockefeller University, raider ants were modified using CRISPR so they could not smell pheromones. The lab studies social behavior and the modified ants were not able to maintain a complex hierarchy normally seen in colonies of raider ants. The team is continuing to use CRISPR to learn more about the genes that are involved in this behavior.
As scientists bring unusual animals into the lab, they’re finding that they’re somewhat unprepared to raise them. The research models we have were developed over decades, and as our lab skills grew, we easily incorporated new information into what we already knew. Building new research models will take a lot of effort, as scientists learn more about the life and breeding cycles, environmental, and nutritional needs of these animals, for example.
“The reason classic model systems were chosen was they’re basically pests. Nothing can stop them growing,” added Montague. “But if we take on this challenge of working on new organisms because they have an amazing feature, they’re often not happy to grow under [just] any conditions.”
The National Science Foundation is supporting these efforts, which are already bearing fruit. Investigators at the University of Georgia in Athens have recently been able to generate the first genetically modified reptile using CRISPR.
Learn more about why animal models are used in research from the video.
This work could bring new insight to many old problems. Ferrets are a great way to model influenza because the virus can grow in their respiratory system, and they occasionally sneeze while infected. But scientists did not have a good way to change the ferret genome until CRISPR arrived. Chinese researchers are now creating a ferret that is susceptible to the virus.
Bioethicists will undoubtedly be keeping an eye on these developments. As with traditional research models, scientific experiments should be properly justified before embarking on animal studies.