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In 1963, on a hunch, a South African biologist named Sydney Brenner decided to study a species of worms named C. elegans.

The worms turned out to be the perfect lab animal. They were simple creatures that lived in the dirt and ate bacteria but were just complicated enough to provide biological insights applicable to human health. C. elegans was the first organism to have its genome sequenced and, aside from humans, have been sent into space more than any other animal.

In 2002, Brenner, along with Robert Horvitz and John Sulston, won the Nobel Prize in Physiology or Medicine for their work describing how cells deliberately kill themselves for the greater good of the whole worm. The same process occurs in human cells as well — most famously in a webbing of skin that would otherwise span our fingers. Investigating normal cell death has helped scientists understand cancer — a disease where cells continue to grow and divide when they should not.


Brenner’s hunch continues to pay off. Current studies with worms are helping us understand how our minds work and how we age.

Eugene Lee, a graduate student in the Horvitz laboratory located on the campus of the Massachusetts Institute of Technology, is using C. elegans to describe how nerve cells work together to give rise to complicated behavior and consciousness. Along the way, he’s spent countless hours examining striking images of a strange microscopic world where the flick of a worm’s tail or an unusual patch of glowing cells could be the next key breakthrough.

C. Elegens
A strain of C. elegans expressing a fluorescent protein in cells. Small dots of fluorescence indicate that proteins have concentrated in the nucleus. Eugene Lee/MIT

A strain of C. elegans expressing a fluorescent protein in cells. Small dots of fluorescence indicate that proteins have concentrated in the nucleus. Scientists have genetically engineered strains of C. elegans to produce fluorescent proteins. The patterns of fluorescence help researchers understand how cells and worms are reacting to stressful situations.


C. Elegens
A petri dish full of worms with a mutation that causes them to crawl in circles. Eugene Lee/MIT
A wild-type worm moving across the bottom of a petri dish. Eugene Lee/MIT
C. Elegens
A C. elegans mutant incapable of laying eggs properly as seen through a blue filter. Eugene Lee/MIT

Most C. elegans are hermaphrodites that possess both female and male organs. Males are rare and no females exist. During its life cycle, a typical hermaphrodite lays about 300 eggs.

C. Elegens
A still image taken from a high-speed video camera. Worms have been placed in a mixture of beads and bacteria used to observe feeding behavior. Eugene Lee/MIT

Scientists are studying the worm nervous system to explain animal behavior. Understanding how and why a worm responds to certain stimuli, like laying eggs in response to bright light, can be tricky. “I actually try to imagine myself as a worm,” said Lee. “We do it all the time in lab.”

C. Elegens
C. elegans exposed to the drug Prozac. Eugene Lee/MIT

Because they are easy to raise in large numbers, worms are useful for drug screens — enormous experiments where scientists test how C. elegans responds to hundreds of different chemicals. Here worms stiffen when exposed to Prozac.

C. Elegens
Group of C. elegans as seen through a green filter. Eugene Lee/MIT
C. Elegens
A strain of C. elegans that expresses a fluorescent protein in cells reacting to heat, oxidative stress, and food deprivation. Eugene Lee/MIT

Researchers have a relationship with worms that is at once reverent, clinically distant, intimate, and obsessive. Over several decades, scientists have identified and mapped the development of all 959 cells in adult hermaphrodites and 1031 cells in adult males. Brenner called C. elegans “nature’s gift to science.”

C. Elegens
Mutant worms that travel in circles and express fluorescent proteins in their muscles cells. Eugene Lee/MIT
  • Cancer is a big problem in the human being worldwide suffering nearly 90.5 million people (GBD 2015) and 14.1 million new cases occur every year in the world (World Cancer Report 2014). Can we able to prevent the disease using the C. elegans as a model as this worm use in scientific investigation significantly. It will be a great help to save the mankind from this painful chronic disease. Hope we will able to solve the problem in the future.

  • Too scarse information – there are a lot of interesting facts about this creature

  • Nice article and pictures. However, please note that C. elegans was not the first organism to have its genome sequenced. Several bacterial species and the eukaryotic yeast Saccharomyces cerevisiae were several years earlier. C. elegans is the first animal genome sequenced, just ahead of fruit flies and humans.

  • Do these worms have heads and tails / fronts and backs? Or is one end just like the other?

    • They look rather featureless externally, but they have a head with a rudimentary brain and a gut that goes from head to tail.

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