Environmental constraints on the physiology of transgenic mosquitoes

Authors

  • P.F. Billingsley

Abstract

Insects have exploited and responded to their environment in a plethora of ways. Environmental changes are used to trigger short- and long-term physiological events and environmental stresses have resulted in evolution of gene families and resistance genes. This highly evolved, tight interaction between organism and environment will be altered in transgenic mosquitoes, and this paper reviews some potential considerations concerning the physiology of transgenic mosquitoes upon release. This papers examines a few of the recent discoveries in Plasmodium-mosquito interactions and discusses the impact upon them of the transgenic-mosquito approach. A complex interplay between vector and parasite occurs during transmission, including the exploitation of xanthurenic acid for triggering exflagellation, the induction of a mosquito immune response and its evasion by the invading ookinete, and the ability of the parasite to establish infections when major genes are knocked out. Such functional redundancy in parasite genes is also demonstrable in the immune and detoxification systems of insects. Consequently, where genes can substitute for one another in a given physiological process, there is potentially significant environmental pressure for differential gene expression. In the transgenic context, such compensatory regulation could work to down-regulate and/or select against a transgene. Conversely, additional environmental triggers could be exploited to select positively for a transgenic mosquito. There is potential for heterogeneity at each stage of the transgenic release strategy, and addressing this will be important if such approaches are not to be scuttled by unforeseen factors that could reduce expression of and selection for the beneficial transgenes

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Published

2004-03-01