Thequeenslandensisand thetypeform of the dengue fever mosquito (Aedes aegyptiL.) are genomically indistinguishable
Authors: Rašić Gordana , Filipović Igor , Callahan Ashley G. , Stanford Darren , Chan Abigail , Gek Lam-Phua Sai , Cheong Tan Huat , Hoffmann Ary A. 
Published: July 2016

Background

The mosquitoAedes aegypti(L.) is a major vector of viral diseases like dengue fever, Zika and chikungunya.Aedes aegyptiexhibits high morphological and behavioral variation, some of which is thought to be of epidemiological significance. Globally distributed domesticAe. aegyptihave been traditionally grouped into (i) the very pale varietyqueenslandensisand (ii) thetypeform. Because the two color forms co-occur across most of their range, there is interest in understanding how freely they interbreed. This knowledge is particularly important for control strategies that rely on mating compatibilities between the release and target mosquitoes, such asWolbachiareleases and SIT. To answer this question, we analyzed nuclear and mitochondrial genome-wide variation in the co-occurring pale andtype Ae. aegyptifrom northern Queensland (Australia) and Singapore.

Methods/Findings

We typed 74 individuals at a 1170 bp-long mitochondrial sequence and at 16,569 nuclear SNPs using a customized double-digest RAD sequencing. 11/29 genotyped individuals from Singapore and 11/45 from Queensland were identified asvar. queenslandensisbased on the diagnostic scaling patterns. We found 24 different mitochondrial haplotypes, seven of which were shared between the two forms. Multivariate genetic clustering based on nuclear SNPs corresponded to individuals’ geographic location, not their color. Several family groups consisted of both forms and threequeenslandensisindividuals wereWolbachiainfected, indicating previous breeding with thetypeform which has been used to introduceWolbachiaintoAe. aegyptipopulations.

Conclusion

Aedes aegypti queenslandensisare genomically indistinguishable from thetypeform, which points to these forms freely interbreeding at least in Australia and Singapore. Based on our findings, it is unlikely that the presence of very paleAe. aegyptiwill affect the success ofAedescontrol programs based onWolbachia-infected, sterile or RIDL mosquitoes.

Author Summary

Aedes aegypti, the most important vector of dengue and Zika, greatly varies in body color and behavior. Two domestic forms of this mosquito, the very palequeenslandensisand the brownertype, are often found together in populations around the globe. Knowing how freely they interbreed is important for the control strategies such as releases ofWolbachiaand sterile males. To answer this question, we used RAD sequencing to genotype samples of both forms collected in Singapore and northern Queensland. We did not find any association between the mitochondrial or nuclear genome-wide variation and color variation in these populations. Rather, “paleness” is likely to be a quantitative trait under some environmental influence. We also detected severalqueenslandensisindividuals with theWolbachiainfection, indicating free interbreeding with thetypeform which has been used to introduceWolbachiaintoAe. aegyptipopulations. Overall, our data show that the very palequeenslandensisare not genomically separate, and their presence is unlikely to affect the success ofAedescontrol programs based onWolbachia-infected, sterile or RIDL mosquitoes.