July 1, 2013 The idea that worms can be seen as waveforms allowed scientists at Rice University to find new links in gene networks that control movement.

The work led by Rice biochemist Weiwei Zhong, which will appear online this week in the Proceedings of the National Academy of Sciences Early Edition, involved analyzing video records of the movement of thousands of mutant worms of the species Caenorhabditis elegans to identify the neuronal pathways that drive locomotion.

One result was the discovery of 87 genes that, when inactivated, caused movement defects in worms. Fifty of those genes had never been associated with such defects, and 37 have implications in human diseases, the researchers found.

Another discovery was the existence of several network modules among these genes. One module detects environmental conditions. Another resides in all "excitable cells" -- those types that respond to electrical signals -- in the worm's neurons, muscles and digestive tracts. Another coordinates signals in the motor neurons.

The team also uncovered new details about a protein-signaling pathway found in all animals, Zhong said.

Zhong said the study is the first to provide a system-level understanding of how neuronal signaling genes coordinate movement and shows the value of a quantitative approach to genetic studies. She said the approach could be useful in studies of gene-to-drug or drug-to-drug interactions.

What made the research possible is the fact that cameras and computers are able to see variations in movement that are too small for eyes and minds to notice, Zhong said. "The idea is that if a gene is required for maintaining normal movement and we pick a mutant, the computer should be able to detect the defects," she said.

"I'm very observant," she said, "and I thought I could tell the worms with abnormal behaviors. I was surprised to see there were so many things I missed that the computer picked up."

The Rice researchers, with help from associates at the California Institute of Technology and Howard Hughes Medical Institute (HHMI), analyzed 239 mutant C. elegans, a common worm used in studies since the 1970s. Including a set of "wild-type" C. elegans that was used as a baseline, the Rice lab studied more than 4,400 worms. Each type was ordered from the Caenorhabditis Genetics Center and separated by mutation.

The worms were filmed one at a time. Each was placed in a petri dish (seeded with E. coli bacteria for food) on a motorized platform and filmed by a computer-controlled camera/microscope. The computer re-centered the camera on the worms any time they moved near the edge of the camera's field of view.

See the article here:
Wiggling worms make waves in gene pool

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