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Member Research & Reports

Member Research & Reports

Yale: Transgenic Mosquitoes Pass on Genes to Native Species

Transgenic mosquitoes released in Brazil in an effort to reduce the population of disease-bearing insects have successfully bred and passed on genes to the native mosquito population, a new Yale research study published Sept. 10 in the journal Scientific Reports has found.

Tens of millions of genetically modified male Aedes aegypti mosquitoes were released over more than two years in Jacobina, in Bahia, Brazil. Females who mated with males carrying these modified genes were supposed to be unable to produce viable offspring, thereby reducing people’s risk of contracting a host of dangerous diseases such as Zika, dengue fever, and yellow fever.

However, samples of native mosquitoes harvested in the region and analyzed at Yale revealed that some members of the native population had retained genes from the transgenic release strain.

“The claim was that genes from the release strain would not get into the general population because offspring would die,’’ said senior author, Dr. Jeffrey Powell, professor of ecology and evolutionary biology. “That obviously was not what happened.”

Dr. Powell stressed that the mixing of the transgenic strain and native population poses no known health risk.

“But it is the unanticipated outcome that is concerning,” he said. “Based largely on laboratory studies, one can predict what the likely outcome of the release of transgenic mosquitoes will be, but genetic studies of the sort we did should be done during and after such releases to determine if something different from the predicted occurred.”

Dr. Powell has a joint appointment at the Yale School of Public Health.

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