An ace-1 gene duplication resorbs the fitness cost associated with resistance in Anopheles gambiae, the main malaria mosquito Assogba, B. S. Djogbenou, L. S. Milesi, P. Berthomieu, A. Perez, J. /Ayala, Diego /Chandre, Fabrice Makoutode, M. Labbe, P. Weill, M. Widespread resistance to pyrethroids threatens malaria control in Africa. Consequently, several countries switched to carbamates and organophophates insecticides for indoor residual spraying. However, a mutation in the ace-1 gene conferring resistance to these compounds (ace-1(R) allele), is already present. Furthermore, a duplicated allele (ace-1(D)) recently appeared; characterizing its selective advantage is mandatory to evaluate the threat. Our data revealed that a unique duplication event, pairing a susceptible and a resistant copy of the ace-1 gene spread through West Africa. Further investigations revealed that, while ace-1(D) confers less resistance than ace-1(R), the high fitness cost associated with ace-1(R) is almost completely suppressed by the duplication for all traits studied. ace-1 duplication thus represents a permanent heterozygote phenotype, selected, and thus spreading, due to the mosaic nature of mosquito control. It provides malaria mosquito with a new evolutionary path that could hamper resistance management. 2015 text https://www.documentation.ird.fr/hor/fdi:010065360 fdi:010065360 Assogba B. S., Djogbenou L. S., Milesi P., Berthomieu A., Perez J., Ayala Diego, Chandre Fabrice, Makoutode M., Labbe P., Weill M.. An ace-1 gene duplication resorbs the fitness cost associated with resistance in Anopheles gambiae, the main malaria mosquito. 2015, 5, art. 14529 [12 p.] EN AFRIQUE SUBSAHARIENNE