Comparative fitness assessment of Anopheles stephensi transgenic lines receptive to site-specific integration.

Genetically modified mosquitoes that are unable to transmit pathogens offer opportunities for controlling vector-borne diseases such as malaria and dengue. Site-specific gene recombination technologies are advantageous in the development of these insects because antipathogen effector genes can be inserted at integration sites in the genome that cause the least alteration in mosquito fitness. Here we describe Anopheles stephensi transgenic lines containing phi C31 attP'docking' sites linked to a fluorescent marker gene. Chromosomal insertion sites were determined and life-table parameters were assessed for transgenic mosquitoes of each line. No significant differences in fitness between the transgenic and nontransgenic mosquitoes were detected in this study. These transgenic lines are suitable for future site-specific integrations of antiparasite transgenes into the attP sites.

Over expression of a cytochrome P450 (CYP6P9) in a major African malaria vector, Anopheles Funestus, resistant to pyrethroids.

Anopheles funestus Giles is one of the major African malaria vectors. It has previously been implicated in a major outbreak of malaria in KwaZulu/Natal, South Africa, during the period 1996 to 2000. The re-emergence of this vector was associated with monooxygenase-based resistance to pyrethroid insecticides. We have identified a gene from the monooxygenase CYP6 family, CYP6P9, which is over expressed in a pyrethroid resistant strain originating from Mozambique. Quantitative Real-Time PCR shows that this gene is highly over expressed in the egg and adult stages of the resistant strain relative to the susceptible strain but the larval stages showed almost no difference in expression between strains. This gene is genetically linked to a major locus associated with pyrethroid resistance in this A. funestus population.