Featured Research

from universities, journals, and other organizations

Convergent Evolution Of Molecules In Electric Fish

Date:
March 6, 2006
Source:
University of Texas at Austin
Summary:
Having a set of extra genes gave fish on separate continents the ability to evolve electric organs, report researchers from The University of Texas at Austin. Dr. Harold Zakon and colleagues, in a paper recently published in Proceedings of the National Academy of Sciences, show that African and South American groups of fish independently evolved electric organs by modifying sodium channel proteins typically used in muscle contraction.

Weakly electric fish from South America, Sternarchorhynchus mormyrus, and Africa, Campylomormyrus phantasticus. Both fish evolved the ability to generate and sense electric fields. These two species also independently evolved curved jaws for bottom feeding. Electric discharges for each species are indicated.
Credit: Image s courtesy of Carl D. Hopkins and John Sullivan

Having a set of extra genes gave fish on separate continents the ability to evolve electric organs, report researchers from The University of Texas at Austin.

Dr. Harold Zakon and colleagues, in a paper recently published in Proceedings of the National Academy of Sciences, show that African and South American groups of fish independently evolved electric organs by modifying sodium channel proteins typically used in muscle contraction.

Mutations in sodium channel proteins can cause serious muscular disorders, epilepsy and heart problems in humans and other vertebrates.

But fish have two copies of many of their genes, and Zakon found that the duplicate sodium channel gene could mutate and evolve without harming the fish.

“The spare gene gave [the electric fish] a little bit of evolutionary leeway,” says Zakon, professor of neurobiology. “This is really one of the first cases that the ancestral gene duplication in fish has actually been linked to a gene that has been freed up and evolving in accordance with a ‘new lifestyle.’”

Zakon and colleagues looked at two sodium channel genes in the electric organs and muscles in electric and non-electric fish. Electric fish use their electric organs, which are modified muscles, to communicate with each other and sense their environment.

The researchers found that electric fishes expressed one of the sodium channel genes in their electric organs only, while non-electric fish express both genes in their muscles.

“Most fish have both genes in the muscle, but as the new electric organ was evolving, the sodium channel—by being lost from the muscle—became devoted to the electric organ,” Zakon says. “So two times, independently, the gene has been ‘lost’ from the muscle. It’s no longer able to turn on in a cell that for millions of years it turned on in, and now it’s turning on in this new organ.”

When the research team looked at the sodium channel protein sequences, they found that some of the mutations occurred at the same or very close to sites in the protein where mutations have been shown to cause disease in humans.

“Functionally important parts of this molecule are changing in order to change the electrical discharge in the fish—changes that would be detrimental in a human muscle,” says Zakon.

Looking at the convergent evolution of sodium channels in these fish helps neurobiologists identify important parts of these proteins relevant to human health, adds Zakon.

“When natural selection is acting to cause changes in a part of a molecule, you know it’s functionally important,” he says. “Natural selection can start showing you the important parts of molecules. We took the evolutionary approach, which is very compatible with the clinical approach.”
The research team included evolutionary biologist Dr. David Hillis, graduate student Derrick Zwickl and research associate Ying Lu.


Story Source:

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


Cite This Page:

University of Texas at Austin. "Convergent Evolution Of Molecules In Electric Fish." ScienceDaily. ScienceDaily, 6 March 2006. <www.sciencedaily.com/releases/2006/03/060303114337.htm>.
University of Texas at Austin. (2006, March 6). Convergent Evolution Of Molecules In Electric Fish. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2006/03/060303114337.htm
University of Texas at Austin. "Convergent Evolution Of Molecules In Electric Fish." ScienceDaily. www.sciencedaily.com/releases/2006/03/060303114337.htm (accessed July 25, 2014).

Share This




More Plants & Animals News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Newsy (July 24, 2014) A new study claims a set of prehistoric T-Rex footprints supports the theory that the giant predators hunted in packs instead of alone. Video provided by Newsy
Powered by NewsLook.com
Dogs Appear To Become Jealous Of Owners' Attention

Dogs Appear To Become Jealous Of Owners' Attention

Newsy (July 23, 2014) A U.C. San Diego researcher says jealousy isn't just a human trait, and dogs aren't the best at sharing the attention of humans with other dogs. 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