Mosquitoes are vectors of devastating human diseases, including malaria, dengue, yellow fever, and Zika. Anopheles gambiae is the most efficient vector of malaria and a primary focus of wide-scale control programs based on use of insecticides. Rapid evolution and spread of insecticide resistance threaten the effectiveness of the current programs and call for novel more sustainable approaches, such as genetic control. Sex-specific molecular interactions occurring during mosquito development may offer a plethora of molecular targets for genetic control. However, the corresponding molecular circuits and their elements are very poorly known.
Here we present a detailed high-throughput study of the sexed developmental transcriptome of A.gambiae. Comparisons between the male and female expression levels revealed several distinct sex-specific developmental processes. We found that in males, genes on the single X chromosome are significantly upregulated, consistent with operational dosage compensation in larvae and pupae. Differentially expressed genes across male and female development are related to sex-specific functions. Clustering analysis, followed by experimental validation, revealed that, among temporal developmental profiles, the most distinct corresponds to spermatogenesis, enabling prediction of function for a large number of yet unannotated genes related to sexual development. We have characterized splicing patterns across development, with special focus on sex-specific splicing. We also identified candidate genes involved in sex determination and sex-dependent regulatory interactions. Finally, we have looked at the evolution of expression profiles across developmental stages in A. gambiae and other insects.
Our analysis sheds new light on the transcriptional and developmental landscape of A. gambiae and lays the foundation for research into the components of sex determination, dosage compensation machinery, and sexual development in this important vector species.