A given neuron can express multiple members of several chemoreceptor gene families
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Single-nucleus RNA-sequencing points to an unexpectedly large diversity of neurons
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Chemoreceptor co-expression is functionally relevant to odorant responses
Summary
Aedes aegypti mosquitoes are a persistent human foe, transmitting arboviruses including dengue when they feed on human blood. Mosquitoes are intensely attracted to body odor and carbon dioxide, which they detect using ionotropic chemosensory receptors encoded by three large multi-gene families. Genetic mutations that disrupt the olfactory system have modest effects on human attraction, suggesting redundancy in odor coding. The canonical view is that olfactory sensory neurons each express a single chemosensory receptor that defines its ligand selectivity. We discovered that Ae. aegypti uses a different organizational principle, with many neurons co-expressing multiple chemosensory receptor genes. In vivo electrophysiology demonstrates that the broad ligand-sensitivity of mosquito olfactory neurons depends on this non-canonical co-expression. The redundancy afforded by an olfactory system in which neurons co-express multiple chemosensory receptors may increase the robustness of the mosquito olfactory system and explain our long-standing inability to disrupt the detection of humans by mosquitoes.
snRNA-seq data have been deposited as an NCBI BioProject and are publicly available under the accession number listed in the key resources table.
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All original code and custom scripts, along with additional raw data not found in Data S1 as well as plots and additional analysis have been deposited at Github and at Zenodo and are publicly available. DOIs are listed in the key resources table.
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Microscopy data reported in this paper will be shared by the lead contact upon request.
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Any additional information required to reanalyze the data reported in this paper is available from the lead contact upon request.
