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CRISPR gene editing creates waves of exotic model creatures

Hawaii Rice Tail Squid

Hawaiian bobtail squid (Euprymna scolopes) changes the camouflage pattern according to the skin you see.Credits: Eric Roettinger / Kahi Kai Images

Joseph Parker wanted to know why beetles made beetles since he was 7 years old. Entomologists have spent decades collecting and observing insects, some of them living in ants and eating their larvae. But without the tools to study the genetic and brain mechanisms of beetle behavior, Parker focused on his doctoral studies. Drosophila Fruit flies – an established model organism.

Ten years later, Parker's childhood dreams came true with the advent of CRISPR gene editing technology. He is using CRISPR to study symbiosis in Robe beetle (Staphylinidae) In the laboratory of the California Institute of Technology in Pasadena, California. Parker wants to see how the insect's DNA is changing by removing the genes in beetles that live with ants and not in other beetles. "We are designing the model system from scratch," he says.

Biologists have embraced CRISPR's ability to rapidly and inexpensively modify genomes of popular model organisms such as mice, fruit flies, and monkeys. Now they are trying out some more tools for alien species. Many of them have never been raised in the laboratory or have never been analyzed for genomics. "We are finally ready to start expanding what we call model organisms," said Tessa Montague, a molecular biologist at Columbia University in New York City.

Montague works in the Hawaiian bobtail squidEuprymna scolopes) And dwarf squidSepia band), A species in which abnormal stomachs act as an external marker of brain activity. Cephalopods project a pattern on their skin to match what they see around. However, it was difficult to probe how the brain treats the stimuli. Researchers usually do this by inserting an electrode or other sensor into the skull, but squid and squid have no bones.

Last year, Montague and her colleagues successfully injected CRISPR ingredients into squid and pork squid embryos for the first time. Now, they are trying to genetically correct the neurons of the tofu cerebral cortex when they are hoofed.

Technical knockout

Other researchers are using CRISPR to study the unique social behavior of species. Daniel Kronauer, a biologist at Rockefeller University in New York,Ooceraea biroi) Pheromone Does not smell. In the experiment, genetically engineered ants were unable to maintain the complex hierarchy found in normal radar-ant colonyOne. Scientists now use CRISPR to alter genes that are thought to affect the behavior of spider ants.

If so, the species that threatens human or environmental health – pea aphid (pea)Acylinspyridine), Insects attacking soybeans and crops around the world. To edit the genome of aphids with CRISPR, a team led by the evolutionary geneticist Shuji Shigenobu of the Okazaki National Basic Biology Laboratory in Japan had to manipulate the complex life cycle of insects. Female aphids born in summer are cloned and reproduced asexually, whereas females born in autumn produce eggs.

The Shigenobu research team set up an incubator that simulated cold temperatures and cold short blades, giving scientists the eggs to inject CRISPR components.

Over the past four years, Shigenobu has successfully edited the pigment gene as proof of concept four years later during the past four years at a meeting at the Janelia Research Campus of the Howard Hughes Medical Institute in Ashburn, Virginia, for the past four years, Shigenobu said. He hopes to know more about how insects interact with plants by modifying different parts of the genome of aphids. That information can lead to the production of better pesticides.

Strike forward

Developing animal models takes a lot of time and money, and until recently there was little support for such work. In 2016, the National Science Foundation launched a $ 24 million program to create model organisms, thereby revealing the genetic and molecular mechanisms of complex traits and behavior.

The program supports research to create tools for exploring species genomes, studying the life cycle of organisms, and developing protocols for raising these species in laboratories. This support has begun to pay off. For example, researchers at the University of Georgia in Athens in March2 Using CRISPR, the first genetically modified reptilian brown anole (Arnold S. Gray).

Despite these promising early results, efforts to create model organisms with CRISPR have revealed that few are known about many species of genomes, life cycles, and habits. The researchers face practical challenges such as determining how CRISPR components are injected into the embryo and extracting tricky and fragile species to breed in the laboratory.

"The reason we chose the classic model system is basically a pest. There is no way to prevent them from growing." But if we do this task of studying new organisms because we have amazing features, they often grow It is difficult to do. [just] Any condition. "

This forced scientists to endure the effort needed to study certain characteristics in preparation for potential rewards. Modifying the genome requires a deeper understanding of the species' behavior and life cycle. Only a few people around the world are studying the organism. David Stern, a biologist at Janelia, says, "People do not lightly choose these model systems.

Stern knows this first hand. He and his colleagues succeeded in breeding fruit fly species only after they found that insects needed the olfactory nipple to lay their eggs. It was the smell of certain chemicals made by plants.

Still, the interest of researchers developing atypical animal models continues to grow. Montague and her colleagues created a tool called CHOPCHOP, which you can use to design a CRISPR system that allows you to edit specific genes in DNA fragments. So far, scientists have sent gene sequences of more than 200 different species, including plants, fungi, viruses and farm animals.

"We knew this molecular tool was effective this week on almost every organism on earth," Montague says. "It's a very exciting time to study any new model creature, especially new and strange creatures."

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