Analysis of Clock Gene Circadian Expression in Two Mosquitoes

*Corresponding author e-mail: gbsrivas@ioc.fiocruz.br Introduction: Mosquitoes show a range of activity patterns, from diurnal, to crepuscular and nocturnal. Although activity and blood-feeding rhythms are controlled by the circadian clock, it is yet unknown whether such species-specific differences in behaviour are directly controlled by core clock genes rather than reflecting differences in how the information of the central clock is translated into output signals. Methods: To begin addressing this question we initiated a comparative analysis of the circadian expression of clock genes in two important mosquito vectors of tropical diseases, Aedes aegypti and Culex quinquefasciatus , which show very different locomotor activity patterns. Under controlled laboratory conditions Ae. aegypti is mainly active in the photophase, while Cx. quinquefasciatus activity is largely restricted to the scotophase. Using quantitative Real-Time PCR, we analysed the expression of several clock genes of these two species in light-dark (LD) and constant dark (DD) conditions. Results and Conclusion: The results show generally conserved circadian expression patterns for all genes except the mammalianlike cryptochrome- 2 (cry2). Publication History Article published online: 16 June 2026 © 2009. Brazilian Sleep Academy. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/) Thieme Revinter Publicações Ltda. Rua Rego Freitas, 175, loja 1, República, São Paulo, SP, CEP 01220-010, Brazil