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THE STERILE INSECT TECHNIQUE (SIT) IS AN INSECT PEST CONTROL STRATEGY IN WHICH MALES ARE MASS-REARED IN A LAB, STERILIZED, AND RELEASED INTO THE ENVIRONMENT. WHEN THE STERILIZED MALES MATE WITH WILD FEMALES IN THE FIELD, HER EGGS FAIL TO HATCH, THEREBY SUPPRESSING OR ERADICATING THE LOCAL POPULATION. HISTORICALLY, STERILIZATION HAS BEEN ACCOMPLISHED WITH IRRADIATION, BUT TRANSGENIC STERILIZATION METHODS HAVE BEEN DEVELOPED THAT OVERCOME THE NEED FOR IRRADIATION. TRANSGENIC STERILIZATION TYPICALLY RELIES ON CONDITIONALLY LETHAL TRANSGENES THAT PRODUCE A TOXIC PROTEIN THAT CAUSES EMBRYONIC DEATH EARLY IN DEVELOPMENT. THESE TRANSGENES ARE CONTROLLED BY A DRUG-SUPPRESSIBLE PROMOTER, SO THAT FLIES HARBORING THE TRANSGENE CAN BE PROPAGATED IN THE LAB BY ADDING THE DRUG IN THEIR DIET. CONDITIONAL LETHALITY STRAINS HAVE BEEN DEVELOPED FOR SEVERAL ECONOMICALLY IMPORTANT FRUIT FLIES, AND SIMILAR STRATEGIES HAVE BEEN DEVELOPED FOR MEDICALLY RELEVANT SPECIES LIKE MOSQUITOES.DESPITE THE POTENTIAL BENEFITS OF TRANSGENIC SIT, THERE ARE SEVERAL PUBLIC AND REGULATORY CONCERNS OVER ITS IMPLEMENTATION. THESE CONCERNS INCLUDE POTENTIAL TOXICITY OF THE TRANSGENE TO OFF-TARGET ORGANISMS, ECOLOGICAL CHANGES IN THE INSECTS CARRYING THE TRANSGENE, AND DEVELOPMENT OF RESISTANCE. ALL OF THESE RISKS ARE MAXIMIZED IF THE TRANSGENE PERSISTS IN THE ENVIRONMENT. HOWEVER, THE EFFICACY OF CONDITIONALLY LETHAL TRANSGENES IN THE FIELD AND THE ENVIRONMENTAL FACTORS THAT CONTRIBUTE TO TRANSGENE FAILURE HAVE NOT BEEN ASSESSED. THE OBJECTIVE OF OUR PROJECT IS TO DETERMINE THE EXTENT TO WHICH GENOTYPE, ENVIRONMENTAL CONDITIONS, AND EVOLUTIONARY CHANGE IMPACT THE EFFECTIVENESS OF CONDITIONALLY LETHAL TRANSGENES. SPECIFICALLY, WE WILL 1) TEST THE EXTENT TO WHICH NATURALLY OCCURRING GENETIC VARIATION IMPACTS THE EXPRESSION AND ACTIVITY OF CONDITIONALLY LETHAL TRANSGENES, 2) IDENTIFY ENVIRONMENTAL CONDITIONS THAT COMPROMISE EXPRESSION AND ACTIVITY OF LETHAL TRANSGENES, AND 3) TEST THE EXTENT TO WHICH NATURAL POPULATIONS CAN EVOLVE RESISTANCE TO CONDITIONALLY LETHAL TRANSGENES. OUR EXPERIMENTS WILL BE CONDUCTED IN THE MODEL FLY DROSOPHILA MELANOGASTER, WHICH HAS AN ABUNDANCE OF GENETIC RESOURCES AVAILABLE AND IS CLOSELY RELATED TO SEVERAL FLIES FOR WHICH TRANSGENIC SIT IS BEING DEVELOPED. OUR PROJECT ALIGNS WELL WITH USDA BRAG PROGRAM AREA #1: MANAGEMENT PRACTICES TO MINIMIZE ENVIRONMENTAL RISK OF GE ORGANISMS AND WILL PROVIDE CRITICAL INFORMATION TO REGULATORY AGENTS REGARDING THE POTENTIAL RISKS OF RELEASING TRANSGENIC ARTHROPODS INTO THE ENVIRONMENT.

$500,000FY2017National Institute of Food and AgricultureUSDA

University Of Kentucky Research Foundation, The

Investigators

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THE STERILE INSECT TECHNIQUE (SIT) IS AN INSECT PEST CONTROL STRATEGY IN WHICH MALES ARE MASS-REARED IN A LAB, STERILIZED, AND RELEASED INTO THE ENVIRONMENT. WHEN THE STERILIZED MALES MATE WITH WILD FEMALES IN THE FIELD, HER EGGS FAIL TO HATCH, THEREBY SUPPRESSING OR ERADICATING THE LOCAL POPULATION. HISTORICALLY, STERILIZATION HAS BEEN ACCOMPLISHED WITH IRRADIATION, BUT TRANSGENIC STERILIZATION METHODS HAVE BEEN DEVELOPED THAT OVERCOME THE NEED FOR IRRADIATION. TRANSGENIC STERILIZATION TYPICALLY RELIES ON CONDITIONALLY LETHAL TRANSGENES THAT PRODUCE A TOXIC PROTEIN THAT CAUSES EMBRYONIC DEATH EARLY IN DEVELOPMENT. THESE TRANSGENES ARE CONTROLLED BY A DRUG-SUPPRESSIBLE PROMOTER, SO THAT FLIES HARBORING THE TRANSGENE CAN BE PROPAGATED IN THE LAB BY ADDING THE DRUG IN THEIR DIET. CONDITIONAL LETHALITY STRAINS HAVE BEEN DEVELOPED FOR SEVERAL ECONOMICALLY IMPORTANT FRUIT FLIES, AND SIMILAR STRATEGIES HAVE BEEN DEVELOPED FOR MEDICALLY RELEVANT SPECIES LIKE MOSQUITOES.DESPITE THE POTENTIAL BENEFITS OF TRANSGENIC SIT, THERE ARE SEVERAL PUBLIC AND REGULATORY CONCERNS OVER ITS IMPLEMENTATION. THESE CONCERNS INCLUDE POTENTIAL TOXICITY OF THE TRANSGENE TO OFF-TARGET ORGANISMS, ECOLOGICAL CHANGES IN THE INSECTS CARRYING THE TRANSGENE, AND DEVELOPMENT OF RESISTANCE. ALL OF THESE RISKS ARE MAXIMIZED IF THE TRANSGENE PERSISTS IN THE ENVIRONMENT. HOWEVER, THE EFFICACY OF CONDITIONALLY LETHAL TRANSGENES IN THE FIELD AND THE ENVIRONMENTAL FACTORS THAT CONTRIBUTE TO TRANSGENE FAILURE HAVE NOT BEEN ASSESSED. THE OBJECTIVE OF OUR PROJECT IS TO DETERMINE THE EXTENT TO WHICH GENOTYPE, ENVIRONMENTAL CONDITIONS, AND EVOLUTIONARY CHANGE IMPACT THE EFFECTIVENESS OF CONDITIONALLY LETHAL TRANSGENES. SPECIFICALLY, WE WILL 1) TEST THE EXTENT TO WHICH NATURALLY OCCURRING GENETIC VARIATION IMPACTS THE EXPRESSION AND ACTIVITY OF CONDITIONALLY LETHAL TRANSGENES, 2) IDENTIFY ENVIRONMENTAL CONDITIONS THAT COMPROMISE EXPRESSION AND ACTIVITY OF LETHAL TRANSGENES, AND 3) TEST THE EXTENT TO WHICH NATURAL POPULATIONS CAN EVOLVE RESISTANCE TO CONDITIONALLY LETHAL TRANSGENES. OUR EXPERIMENTS WILL BE CONDUCTED IN THE MODEL FLY DROSOPHILA MELANOGASTER, WHICH HAS AN ABUNDANCE OF GENETIC RESOURCES AVAILABLE AND IS CLOSELY RELATED TO SEVERAL FLIES FOR WHICH TRANSGENIC SIT IS BEING DEVELOPED. OUR PROJECT ALIGNS WELL WITH USDA BRAG PROGRAM AREA #1: MANAGEMENT PRACTICES TO MINIMIZE ENVIRONMENTAL RISK OF GE ORGANISMS AND WILL PROVIDE CRITICAL INFORMATION TO REGULATORY AGENTS REGARDING THE POTENTIAL RISKS OF RELEASING TRANSGENIC ARTHROPODS INTO THE ENVIRONMENT. · GrantIndex