Assistant Professor University of Florida Vero Beach, Florida
Aedes aegypti is he most important vector of arboviruses worldwide, including that cause dengue, Zika, chikungunya, and yellow fever. This mosquito originated on islands of the southwest Indian Ocean before spreading to Africa and, more recently, to the Americas and Asia. Migration out of Africa was enabled by the evolution of synanthropy, accompanied by increased capacity for arbovirus transmission, making this mosquito efficient at invading/exploiting human-modified environments and at spreading disease. Using populations from Florida (USA) and coastal Tanzania (East Africa) differing in their degree of synanthropy and vectorial capacity (i.e., efficiency at virus transmission), we investigated genetic divergence via exome sequencing, identifying over 1.6 million single nucleotide polymorphisms (SNPs). Of these, 1,058 had genotypes that were nearly fixed between populations (FST > 0.9) with more than half mapping to 17 outlier genes and roughly one-third to a 920-Kbp island on chromosome 2. The most divergent loci influenced chromatin organization, lipid metabolism, N-linked glycosylation, circadian rhythms, olfaction, saliva bioactivity, and detoxification. The work we present here provides compelling evidence of associations between natural genetic variants and transmission-related characters, and generates hypotheses for future investigation.