Biologists at the University of California San Diego have developed a way to manipulate the genes of an agricultural pest that has caused millions of dollars in damage to high-value berry and other fruit crops.
Research led by Anna Buchman in the lab of insect genetics professor Omar Akbari describes the world’s first mechanism for manipulating genetic inheritance in drosophila suzukii, a fruit fly commonly known as the spotted-wing drosophila.
As reported Tuesday in the authoritative Proceedings of the National Academy of Sciences, Buchman and her colleagues developed a so-called “gene drive” system termed Medea (after the mythological Greek enchantress who killed her offspring) to dramatically influence inheritance rates.
“We’ve designed a gene drive system that dramatically biases inheritance in these flies and can spread through their populations,” said Buchman. “It bypasses normal inheritance rules. It’s a new method for manipulating populations of these invasive pests, which don’t belong here in the first place.”
Native to Japan, the highly invasive fly was first found on the West Coast in 2008 and has now been reported in more than 40 states. The fly uses a sharp organ known as an ovipositor to pierce ripening fruit and deposit eggs directly inside, making it much more damaging than other flies that lay eggs only on top of decaying fruit.
Drosophila suzukii has reportedly caused more than $39 million in revenue losses for the California raspberry industry alone and an estimated $700 million overall per year in the U.S.
In experiments using the new gene drive system, the researchers reported up to 100 percent effective inheritance bias over 19 generations of flies.
“We envision, for example, replacing wild flies with flies that are alive but can’t lay eggs directly in blueberries,” said Buchman.
Applications for the new gene drive system could include spreading genetic elements that confer susceptibility to certain environmental factors, such as temperature. If a certain temperature is reached, for example, the genes within the modified spotted wing flies would trigger its death. Other species of fruit flies would not be impacted by this system.
“This is the first gene drive system in a major worldwide crop pest,” said Akbari, who recently moved his lab to UC San Diego from UC Riverside, where the research began.
