Meeting Abstract

33-5   09:00 - 09:15  Rapid evolutionary response to recurrent release of males carrying a dominant early-embryonic lethal transgene in Drosophila melanogaster Perez-Galvez, FR*; Teets, NM; University of Kentucky; University of Kentucky frpe222@uky.edu

Anthropogenic influences can cause eco-evolutionary responses in insect populations, these responses are well-documented for classic pest control strategies like chemical insecticides. New technologies relying on transgenic lethality systems have been developed to control agricultural and medical pests, but the extent to which these strategies cause evolutionary changes in recipient populations is unclear. In this study, caged populations of Drosophila melanogaster were challenged with low-dose releases of males carrying lethal transgene to characterize potential evolutionary trajectories arising from mutation or standing genetic diversity. Clonal and genetically diverse populations were maintained continuously; transgenic males carrying an early-embryonic conditionally lethal cassette were introduced weekly to the cages. Using a lower release ratio of transgenic flies that does not completely suppress the population, we were able to relax selection pressure and allow for phenotypic and molecular changes. Replicate populations had distinct evolutionary trajectories emerging from mutation and selection pressure. Specifically, in clonal populations the gene expression of the transgenic components reduced to half in experimental replicates, and in one population the ratio of transgenic to wild-type males required for 50% suppression increased from 3:1 to 400:1, confirming possible emergence of resistance against genetic engineering of insect populations in response to repeated releases of transgenic males. While these results indicate that repeated release of transgenic males can lead to evolutionary change, extending our results to natural pest populations will require assessing other factors that influence evolutionary trajectories, e.g., migration, genetic drift, and mating system.