Omar Akbari began using CRISPR as a postdoc in biological engineering at Caltech, soon after the release of a seminal paper on the technology. A decade later, his lab at the University of California, San Diego, uses CRISPR in nearly a dozen insect species.
One of its subjects is Drosophila suzukii, or spotted wing drosophila, a species of fruit fly that cuts holes in soft, ripe fruit like cherries and plums to lay its eggs. The flies, which spoil about $500 million in US fruit crops every year, have already grown resistant to some pesticides.
Akbari’s lab has used CRISPR to modify genes in order to create sterile males and kill females. Were those male flies to be released, they’d mingle with normal flies, and their inability to reproduce could depress the overall population.
Agragene, a company that licensed Akbari’s technology, has raised $5.2 million to commercialize this sterilization method in crop pests. The company is testing the product this year at greenhouses in Oregon.
The possible strategies for controlling pest populations and the diseases they transmit using CRISPR are numerous. “Your experiment is only limited by your ingenuity, to some degree,” says Nikolay Kandul, who works with Akbari at UC San Diego.
But researchers must also contend with biology, and the implications of their choices. For certain systems, like Akbari’s fruit fly edits, a change shouldn’t remain in the population unless gene-edited insects continue to be released. “It’s safe, it’s effective, it’s confinable, it’s not going to persist in the environment,” says Akbari.
“You’re gathering enough data to show that your sterile insect is, in this case, safe,” says Agragene CEO Bryan Witherbee, who previously worked at Monsanto and other biotech companies.
The tests Agragene completed last year gave the company confidence that its sterile bugs could survive and function like nonedited bugs, says Witherbee, and the company also worked on techniques to manufacture sterile insects at scale.