Today’s guest post was contributed by Jenny Montooth, a writer and science communicator. Jenny is passionate about using creative and innovative strategies to make complex topics engaging and accessible to wider audiences. You can follow Jenny on LinkedIn.

It’s hard to imagine, but the tiny, translucent roundworm called C. elegans has approximately 20,470 protein-coding genes—about the same number as humans. This is perhaps one of the many reasons why this common worm was the first multicellular organism to have its genome completely sequenced during the Human Genome Project in 1998. Studying C. elegans has been essential for understanding how genes can help execute and regulate important functions in their microscopic bodies, including many in their surprisingly complex nervous system.

An amazing feature of the roundworm is its clever ability to sense and avoid ultraviolet (UV) light, which can damage DNA and increase risk of disease in unpigmented organisms. While most animals have eyes and photoreceptors to see their surroundings and avoid danger, some tiny creatures don’t have eyes at all. C. elegans make themselves at home in soil and decaying plants to avoid sunlight, but if the worm ends up in light, it quickly moves away. This is thanks to a protein called LITE-1, which acts like a built-in light sensor and helps C. elegans sense harmful UV light and quickly retreat from the sun.

In a new study from GENETICS, researchers from the Buchmann Institute of Molecular Life Sciences in Germany sought to determine the particular nerve cells that used LITE-1 to detect light and signal the nervous system to sense it as danger, then acting to escape. They discovered a single nerve cell called AVG that plays a key role in making the worm work to escape harmful light. It works by using chemical signals to send messages to other cells and warn the nervous system of danger. One of the tiny molecules it messages is NLP-10, which helps the worm stay alert. Think about the adrenaline you feel in a fight-or-flight response that encourages you to run when you feel like you’re in danger. A worm may be having a similar response when it is quickly crawling away.

To confirm the star role of AVG in the worm’s nervous system, researchers used a light-activated tool called optoSynC to essentially turn off the AVG neuron in a worm and prevent it from sending its chemical messages warning of danger. When exposed to blue light, the AVG cell essentially froze, and the worm did not try nearly as hard to escape light as it would normally. By observing the AVG cell in action, researchers found that the neuron becomes stimulated by blue light, but only when the LITE-1 protein is present. This helped confirm that AVG is crucial for a C. elegans escape response. This method is also incredibly innovative for studying one brain cell at a time without affecting the rest of the body.

This research is a perfect example of the importance of comparative genomics—working to understand the genes and functions of an animal to support its health and to perhaps lead to insights for human health. Innovative tools such as optoSynC can also help scientists better understand the important functions of individual nerves in complex parts of the body like the brain and nervous system. Even the smallest of animals have impressive ways of detecting and responding to harm that we can all learn from.

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