Wonderous Worms

Unearthing New Insights Into Health

Worms tend to be long, skinny, wiggly creatures. Their simple bodies lack limbs and a backbone. Most have no eyes. It’s hard to imagine a creature more strikingly different from people. Yet studies of worms have given scientists surprising insights into the basic biology of human life and health.

A tiny worm called Caenorhabditis elegans, or C. elegans, is a favorite among biologists. Unlike worms used for fishing, C. elegans are best viewed with a microscope. Scientists have been studying this simple animal for over 70 years.

“We’ve seen over and over again that these worms can lead to major findings relevant to human health and disease,” says Dr. Ann Rougvie, an expert in C. elegans biology at the University of Minnesota.

Research on these common worms helped lay the foundation for at least four Nobel Prizes. One study revealed how genes can control organ development and cell death. This gave insights into Alzheimer’s disease, AIDS, and more. Another study led to a new class of drugs to treat cancer and other disorders.
C. elegans was also the first animal to have all of its DNA sequenced, every cell named and tracked, and all of its nerve cells mapped.

Like humans, C. elegans has a brain, muscles, digestive system, and more. But the simplicity of worms makes them easier to study. The worm’s entire nervous system, including the brain, is made of just 302 cells.

“This is in contrast to the human brain, which has billions and billions of cells,” Rougvie explains. Yet people and worms have many of the same molecules that carry signals in the brain and nervous system.

By altering specific genes, researchers have created worms that have conditions similar to humans. Examples include dementia, stroke, or heart disease.

“About 50% of the genes in these worms have counterparts in humans,” Rougvie says. By comparing genetic sequences across different animals, scientists can figure out how genes function. And they can learn how genetic glitches can affect health and disease.

In early development, cells follow similar patterns when forming body parts in people and worms. But, C. elegans is transparent, so you can see exactly what’s happening inside.

“The adult worm always has 959 body cells. With a microscope, you can watch development happen from the fertilized egg to the adult,” Rougvie says. “The cells divide in essentially the same pattern in every C. elegans.” So researchers can predict which cells will become muscle, nerve, or other cells. That, plus the worms’ two-to-three week lifespan, has helped shed light on processes like development and aging.

Rougvie manages the NIH-supported Caenorhabditis Genetics Center. It houses over 26,000 genetically unique strains of C. elegans. Some strains are short and fat. Others can glow. Some age faster than others. Scientists around the world can order specific strains of worms for their own research. And they can contribute new strains to the center.

“If everyone gets their worms from us, that means everybody’s using the same strains of worms. And that enhances consistency and reproducibility of research findings,” Rougvie says.

“I’m a strong believer in basic research, which is asking fundamental questions about how life works,” she says. Such basic research in C. elegans more than 30 years ago led to discovery of a new type of molecule, called microRNAs.

“Scientists have since learned that microRNAs are present in all animals. And they’re extremely important to human health and disease,” Rougvie says. “This type of curiosity-driven science helps us learn how life works in general.” The researchers who discovered these molecules received a Nobel Prize last year.