Despite spending his 20-year career in designing strategies to make genetic circuits in engineered bacteria work, Jeff Hasty of the University of California, San Diego still had to admit this thing that he was not able to do, and that is outfoxing the humble bacterium Escherichia coli.
Hasty didn’t have a problem engineering useful, tightly regulated new genetic traits or getting them to work in cells. That was the easy part. What’s harder, he discovered, is maintaining those traits. If a cell needs to divert some of its resources to make a desired protein, it becomes marginally less fit than cells that don’t synthesize it. Inevitably, cells acquire mutations deactivating the introduced genetic circuitry, and the mutants quickly replace the original cells. As a result, the desired characteristic disappears, often within 36 hours.
“It’s not a matter of if, it’s a matter of when,” Hasty said.
How do we maintain the genetic circuitry that we made for the engineered bacteria? This is the question that arises from Jeff’s experience, and the answer might be found on a childhood that I believe all of us have played, and that game is rock-paper-scissors.
More details about this over at Quanta Magazine.
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