Why Do We Behave the Way We Do? New Research Reveals Biology Guiding Different Life Stages

This photograph taken on May 19, 2017 shows a lab technician sorting urine samples for testing for flatworms at Khon Kaen University in the northeastern Thai province of Khon Kaen. Millions of Thais across the rural northeast regularly eat koi pla -- a local dish made of raw fish ground with spices and lime. The pungent meal is quick, cheap and tasty, but it is also a favourite feast for parasites that cause a lethal liver cancer killing up to 20,000 Thais annually. Lillian Suwanrumpha/AFP/Getty Images

The simple worm sometimes behaves differently from others with the exact same genes—an evolutionary advantage that confounds basic genetics, according to a new study.

Researchers studying why the tiny creatures behave a certain way at different life stages found that worms with identical genes and living in the same environment will nonetheless engage in atypical behavior.

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The study, which is published in the journal Cell, involved 50 newborn C. elegans roundworms all living in separate containers. Using a newly developed system, scientists were able to record the worms' behavior for their entire life cycle, which lasts about 50 hours.

"From an evolutionary point of view, we can't have everyone going off the cliff all at once like lemmings–someone's got to be doing something different for a species to survive," said Rockefeller University professor and lead author Cori Bargmann, who studies the biology of the brain.

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Bargmann and her colleagues specifically looked at how the worms acted when they looked for food and they found that a majority began their search at the same time in development. However, some of the worms behaved differently.

It can't be genetic differences because all the worms had the exact same genes. But the varied behaviors could be due to differences in how their nervous systems develop or how chemical messengers in the brain function, Bargmann explained.

"There are patterns at every stage of life that are different from the patterns at other stages, and with the system we created we can see that really clearly in ways that are surprisingly complex and robust," she said. "We can also observe something as complex as individuality and start to break down the biology behind it."

Worms are far less complex organisms than humans, but we share many similar genes, which is why scientists often use worms for research. In addition to behavioral studies, they've also been used to shed light on aging and cancer, according to the Lundquist Lab at the University of Kansas.