Discovering Fresh Perspectives on Human Health

Worms may appear simple and vastly different from humans—they're long, slender, often sightless, and lack limbs or a backbone. Yet, these modest creatures have helped scientists make remarkable discoveries about human biology and health.

One microscopic worm, known as Caenorhabditis elegans or C. elegans, is particularly favored among researchers. Unlike garden worms, these are studied through a microscope. For over seven decades, scientists have explored this tiny organism.

“Time and again, we’ve seen that C. elegans can lead to breakthroughs that impact our understanding of human health,” says Dr. Ann Rougvie, a specialist in C. elegans research at the University of Minnesota.

Research on C. elegans has contributed to the foundation of at least four Nobel Prize-winning studies. These include discoveries on genetic mechanisms that regulate organ growth and cell demise—findings that are relevant to conditions like Alzheimer’s, HIV/AIDS, and cancer. Additionally, this worm was the first animal to have its complete DNA sequence mapped, each of its cells identified, and its entire nervous system charted.

C. elegans has vital systems similar to humans—such as a nervous system, muscles, and digestive organs. However, its simplicity makes it easier to examine. The worm’s entire brain and nerve network consists of just 302 cells.

“Compare that with the human brain, which contains billions of cells,” Rougvie says. Still, despite the size difference, humans and worms use many of the same chemical messengers in the brain and nervous system.

Scientists can alter the worm’s genes to mimic human diseases, such as dementia, strokes, or cardiac issues.

“Around half of the worm’s genes have equivalents in humans,” Rougvie states. Through genetic comparisons across species, researchers gain insights into the roles of different genes and how mutations can lead to illness.

Early development in humans and worms shares many patterns, particularly in how their cells organize into organs. Thanks to the worm’s transparent body, researchers can visually track every stage of development.

“Each adult worm has exactly 959 body cells. Under a microscope, you can observe development from egg to adulthood," says Rougvie. "The cell division processes are highly predictable, which helps us trace how specific cells become muscles, neurons, or other types." With a short two to three-week lifespan, worms are perfect for aging and developmental studies.

Rougvie oversees the Caenorhabditis Genetics Center, supported by the NIH, which holds over 26,000 genetically varied strains of C. elegans. Some variants are short, wider, fluorescent, or age at different rates. Researchers from across the world can request certain strains or offer new ones to the archive.

“When everyone obtains worms from our center, they use identical strains. That standardization boosts the reliability and repeatability of scientific results,” Rougvie explains.

“I strongly support fundamental research—the pursuit of basic knowledge about how life functions,” she continues. This kind of research using C. elegans more than 30 years ago led to the discovery of a molecule class called microRNAs.

“Scientists now know microRNAs exist in all animal species and play a crucial role in human health and disease,” Rougvie says. “Research based on curiosity allows us to understand life better.” The scientists who identified these molecules were honored with a Nobel Prize last year.