Featured Research

from universities, journals, and other organizations

Wiggling worms make waves in gene pool

Date:
July 1, 2013
Source:
Rice University
Summary:
Treating the movements of mutant worms as waveforms allowed for a detailed analysis of the gene networks that control their locomotion.

Researchers at Rice University looked at 13 points of moving mutant worms when measuring 10 parameters -- amplitude, flex, frequency, velocity and wavelength, both forward and backward -- to learn about the gene networks that control their locomotion.
Credit: Zhong Lab/Rice University

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.

Zhong said the computer tracked 13 points along the length of each worm to analyze 10 parameters of its sine wave-like movement: velocity, flex, frequency, amplitude and wavelength, both forward and backward. "Some moved slower; some moved faster; some had exaggerated body bends. But in our database, it all turns into numbers to describe the abnormalities," she said. "It gives us a detailed profile of the worm's movement that's almost like a fingerprint."

As a practical matter, each worm was filmed for four minutes. Even at that, it took nearly a year to capture all 4,400 mutants in motion.

The Rice researchers analyzed at least 10 worms of each mutant type to see if their particular mutations caused the animals to move in similar ways -- which, for the most part, they did. Then they analyzed all mutant data to see whether different mutants move in similar ways. "If they have the same symptoms, then we think these genes are probably involved in the same disorder," Zhong said.

To find how gene networks control particular movements, the team cross-matched metrics that were captured by the computer with data about each gene. "Once we knew how many genes were required for maintaining normal locomotion, we then tried to figure out how these genes interact with each other, how they function together as networks," she said.

The computed gene networks showed interesting features, she said. "Some genes are closely connected to each other but loosely connected to others. When we grouped them, we found several communities," she said. One appears to sense environment via sensory neurons; a second connects neurons, muscles and the digestive tract, "probably encoding some basic machinery in excitable cells." The third network contains genes in "the motor neurons that we expected," Zhong said.

She was most interested to see that the third network revealed evidence that a protein known as G-alpha-Q that also appears in other species -- including humans -- has a previously unknown target in a signaling pathway that regulates locomotion. The team conducted further experiments to confirm the existence of the new target gene, PLC-gamma. She said previous studies likely missed this target because they were too coarse to detect the subtle movement abnormalities caused by a defect in PLC-gamma.

It's the kind of revelation that could help prioritize genetic tests in humans. "You don't have to test 30,000 genes if we can give you one or two candidates," Zhong said. "At the molecular level, it's likely a lot of these gene-gene interactions are also conserved in humans."


Story Source:

The above story is based on materials provided by Rice University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Hui Yu, Boanerges Aleman-Meza, Shahla Gharib, Marta K. Labocha, Christopher J. Cronin Paul W. Sternberg and Weiwei Zhong. Systematic profiling of Caenorhabditis elegans locomotive behaviors reveals additional components in G-protein Gαq signaling. PNAS, 2013 DOI: 10.1073/pnas.1310468110

Cite This Page:

Rice University. "Wiggling worms make waves in gene pool." ScienceDaily. ScienceDaily, 1 July 2013. <www.sciencedaily.com/releases/2013/07/130701151824.htm>.
Rice University. (2013, July 1). Wiggling worms make waves in gene pool. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2013/07/130701151824.htm
Rice University. "Wiggling worms make waves in gene pool." ScienceDaily. www.sciencedaily.com/releases/2013/07/130701151824.htm (accessed April 24, 2014).

Share This



More Plants & Animals News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Monkeys Are Better At Math Than We Thought, Study Shows

Monkeys Are Better At Math Than We Thought, Study Shows

Newsy (Apr. 23, 2014) A Harvard University study suggests monkeys can use symbols to perform basic math calculations. Video provided by Newsy
Powered by NewsLook.com
Raw: Leopard Bites Man in India

Raw: Leopard Bites Man in India

AP (Apr. 22, 2014) A leopard caused panic in the city of Chandrapur on Monday when it sprung from the roof of a house and charged at rescue workers. (April 22) Video provided by AP
Powered by NewsLook.com
Iowa College Finds Beauty in Bulldogs

Iowa College Finds Beauty in Bulldogs

AP (Apr. 22, 2014) Drake University hosts 35th annual Beautiful Bulldog Contest. (April 21) Video provided by AP
Powered by NewsLook.com
805-Pound Shark Caught Off The Coast Of Florida

805-Pound Shark Caught Off The Coast Of Florida

Newsy (Apr. 22, 2014) One Florida fisherman caught a 805-pound shark off the coast of Florida earlier this month. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins