Researchers hope to control mosquito populations and reduce mosquito-borne disease by using transgenic mosquito technology. The proposed model, published in Genetics in February 2011, allows for mosquito and disease control without the use of pesticides. It could therefore be considered a “clean” environmental intervention. In the proposed model, researchers engineer mosquitoes to carry one of two genes. One gene causes males to transmit a toxin through their semen to females that either kills them or renders them infertile. The other gene confers immunity to the toxin in females.
Researchers created the system using mathematical models that describe how genetic modifications in DNA are inherited and how these modifications spread or crash in mosquito populations. An all-male release should cause the population size to decrease because wild females that mate with transgenic males will produce no offspring. A release of transgenic females should increase the prevalence of the modified gene because toxin resistance will be favored in the population.
Researchers found that the model could work in a wide range of conditions. It requires a high frequency of gene transfer, implying that transgenic mosquitoes released accidentally will not leave a lasting impression on the population. Modified genes can be removed from the population by releasing wild-type mosquitoes.
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The model has interesting implications for the use of transgenic technology in controlling animal populations. Ethically, it raises the question of whether or not humans have the innate right to alter the genetics of animal populations. If human health is at risk, do humans have the absolute right to intervene using any methods science may allow? It also offers an interesting approach to disease control. Because arthropod-borne diseases are a major cause of human disease, the reservoir/transmitting population can be an effective target for prevention efforts.