Carl Zimmer in This View of Life:
The vinegar worm (officially known as Caenorhabditis elegans) is about as simple as an animal can be. When this soil-dwelling nematode reaches its adult size, it measures a millimeter from its blind head to its tapered tail. It contains only a thousand cells in its entire body. Your body, by contrast, is made of 36 trillion cells. Yet the vinegar worm divides up its few cells into the various parts you can find in other animals like us, from muscles to a nervous system to a gut to sex organs.
In the early 1960s, a scientist named Sydney Brenner fell in love with the vinegar worm’s simplicity. He had decided to embark on a major study of humans and other animals. He wanted to know how our complex bodies develop from a single cell. He was also curious as to how neurons wired into nervous systems that could perceive the outside world and produce quick responses to keep animals alive. Scientists had studied these two questions for decades, but they still knew next to nothing about the molecules involved. When Brenner became acquainted with the vinegar worm in the scientific literature, he realized it could help scientists find some answers.
Its simplicity was what made it so enticing. Under a microscope, scientists could make out every single cell in the worm’s transparent body. It would breed contentedly in a lab, requiring nothing but bacteria to feed on. Scientists could search for mutant worms that behaved in strange ways, and study them to gain clues to how their mutations to certain genes steered them awry.
Brenner’s instinct proved correct. In 2002, he shared the Nobel Prize with John Sulston and Robert Horvitz for their research on the vinegar worm. Other scientists have done pioneering work on the animal as well, with over 22,000 papers published on it over the past five decades. Today, they show no signs of slowing down.
But something fascinating unfolded along the way.