Featured Research

from universities, journals, and other organizations

How a fish can fry: Scientists uncover evolutionary clues behind electric fish

Date:
April 29, 2014
Source:
Molecular Biology and Evolution (Oxford University Press)
Summary:
Take a muscle cell, modify it over millions of years, and you end up with an exciting and literally shocking evolutionary result: the electric fish. The authors of a new study speculate that the down-regulation of the Scn4aa gene leads to quicker evolution and adaptation. Electric fish have evolved several times in varying levels of complexity. By emitting and sensing weak electrical signals, the fish have bypassed the usual means of communication, such as with sounds and visual signals, and go directly to electrical signals. This allows them to quietly "talk" to each other in the dark so that most predators can't eavesdrop.

Take a muscle cell, modify it over millions of years, and you end up with an exciting and literally shocking evolutionary result: the electric fish. Electric fish have evolved several times in varying levels of complexity. Two groups of electric fish, one in Africa (Mormyroids) and one in South America (Gymnotiforms), have independently evolved sophisticated communication systems using these cells. By emitting and sensing weak electrical signals, the fish have bypassed the usual means of communication, such as with sounds and visual signals, and go directly to electrical signals. This allows them to quietly "talk" to each other in the dark so that most predators can't eavesdrop. Both groups of fish are incredibly diverse; one species, the famous electric eel of South America, even evolved such strong and intense electric signals that it can electrocute its prey.

A gene that is particularly important for electric cells is the voltage-gated sodium channel. During an ancestral gene duplication event, the voltage-gated sodium channel of muscle, Scn4a, duplicated to Scn4aa and Scn4ab. This caused sodium ion channel genes to diversify and in parallel the same duplicate gene, Scn4aa, specialized for electric cells in Africa and South America while the other, Scn4ab, remained specialized for muscles. The regulated currents flow through the ion channels and generate electrical signals. In the advanced online publication of Molecular Biology and Evolution, authors Ammon Thompson et al., showed that the Scn4aa sodium channel gene may have an evolutionary bias over its twin to take part in novel cell types derived from muscle cells.

Evidence for their hypothesis was provided by RT-qPCR data of Scn4aa and Scn4ab from electric fish, which were compared with non-electric fish. They speculate that the down-regulation of the Scn4aa gene leads to quicker evolution and adaptation. Also, in an exciting discovery, they found this same Scn4aa gene expression pattern in a species of fish that uses sound to communicate, showing another extraordinary evolutionary adaption from the ancient gene duplication. The results provide a compelling hypothesis that gene duplications and gene 'expression drift' may be a more common evolutionary phenomenon in the development of new organ systems.

By peering into the evolutionary history of these genes we're starting to understand why the same gene plays a role in the repeated evolution of these unusual organs," said researcher Ammon Thompson.


Story Source:

The above story is based on materials provided by Molecular Biology and Evolution (Oxford University Press). Note: Materials may be edited for content and length.


Journal Reference:

  1. A. Thompson, D. Vo, C. Comfort, H. H. Zakon. Expression Evolution Facilitated the Convergent Neofunctionalization of a Sodium Channel Gene. Molecular Biology and Evolution, 2014; DOI: 10.1093/molbev/msu145

Cite This Page:

Molecular Biology and Evolution (Oxford University Press). "How a fish can fry: Scientists uncover evolutionary clues behind electric fish." ScienceDaily. ScienceDaily, 29 April 2014. <www.sciencedaily.com/releases/2014/04/140429184844.htm>.
Molecular Biology and Evolution (Oxford University Press). (2014, April 29). How a fish can fry: Scientists uncover evolutionary clues behind electric fish. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2014/04/140429184844.htm
Molecular Biology and Evolution (Oxford University Press). "How a fish can fry: Scientists uncover evolutionary clues behind electric fish." ScienceDaily. www.sciencedaily.com/releases/2014/04/140429184844.htm (accessed July 24, 2014).

Share This




More Plants & Animals News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
Professor Creates Site Revealing Where People's Cats Live

Professor Creates Site Revealing Where People's Cats Live

Newsy (July 23, 2014) ​It's called I Know Where Your Cat Lives, and you can keep hitting the "Random Cat" button to find more real cats all over the world. Video provided by Newsy
Powered by NewsLook.com
Stone Fruit Listeria Scare Causes Sweeping Recall

Stone Fruit Listeria Scare Causes Sweeping Recall

Newsy (July 22, 2014) The Wawona Packing Company has issued a voluntary recall on the stone fruit it distributes due to a possible Listeria outbreak. Video provided by Newsy
Powered by NewsLook.com
Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
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