Human Odor Detection in Blood-Drinking Mosquitoes
The Younger lab studies olfaction in mosquitoes. The primary focus of the lab is to learn about how mosquitoes detect and encode human odor and how this drives their search for a human to bite. Mosquito-borne diseases affect millions of people worldwide and claim more than half a million lives each year. Only female mosquitoes bite, and they do so because they require a blood-meal for reproduction. Female mosquitoes rely heavily on human-derived chemosensory cues as they search for a blood meal and understanding how mosquitoes detect and encode human odor would provide a major inroad to preventing mosquito biting behavior and disease transmission.
The study of mosquito olfaction provides a rare opportunity to address fundamental questions about sensory neuroscience while working on a global public health problem. Much of what we know about olfaction comes from the study of a few genetically tractable model organisms wherein the principles that govern the organization of the sensory periphery were established. The cannon of olfaction is that individual olfactory sensory neurons express a single type of olfactory receptor and project to discrete regions, called glomeruli, in the first processing center of the brain. This “one-receptor-to-one-neuron-to-one-glomerulus” organization is believed to be a widespread motif in olfactory systems that allows the brain to parse which receptors are activated. The olfactory system of Aedes aegypti, the mosquito that transmits dengue, Zika and yellow fever, is organized in a manner that is different from the canonical organization, with many more receptors than glomeruli and widespread receptor co-expression in olfactory sensory neurons. Our lab seeks to understand the principles of olfaction in this and other mosquito species.
The Younger lab develops and uses a combination of modern neuroscience approaches newly developed for use in mosquitoes to study olfaction. We use CRISPR-based gene editing approaches to label different neuron types, complemented by functional imaging and electrophysiology during precise odor delivery and quantification. Our approach enables us to combine function with anatomy, generating static maps of the mosquito brain at the light level in conjunction with whole-brain serial section electron microscopy. The lab aims to apply these approaches to understand mosquito olfaction and develop novel strategies to thwart these deadly insects.