The discovery, made in the laboratory of biological control extension specialist Mark Hoddle, has been included in the latest issue of the journal Proceedings of the National Academy of Sciences. It is a critical piece of the puzzle in the search for ways to combat mosquito-carried illnesses, such as yellow fever and dengue, because transgenic mosquitoes must be able to compete in the wild in order to combat the illnesses.

Up to now, scientists have debated whether transgenic mosquitoes would have similar or reduced levels of fitness relative to their untransformed counterparts. This work shows that their fitness is dramatically decreased.

Postgraduate researcher Nicola Irvin, under Hoddle's supervision and in collaboration with Professor Peter Atkinson, was able to quantify the fitness of three different transgenic strains of Aedes aeypti, the mosquito vector of yellow fever and dengue. Irvin found that nearly all aspects of development and reproduction of transgenic mosquitoes was severely impaired when compared to non-engineered mosquitoes of the same type.

For example, in four consecutively laid batches of eggs, non-transformed mosquitoes survived from egg to adulthood between 17 and 64 percent of the time. That percentage was between 0 and 23 for transgenic mosquitoes. The average number of eggs laid by non-engineered mosquitoes ranged between 46 and 90, while for transgenic mosquitoes the range was between 14 and 58.

"These data have major implications for the competitiveness of transgenic mosquitoes with non-transformed wild-types," said Hoddle. "Analyses indicate that since engineered mosquitoes lay fewer eggs and egg-adult survivorship is lower they will not be able to increase their population mass after release and therefore will be u
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Contact: Kris Lovekin
kris.lovekin@ucr.edu
909-787-2495
University of California - Riverside
14-Jan-2004