Featured Research

from universities, journals, and other organizations

Transgenic Fish Could Threaten Wild Populations

Date:
January 26, 2000
Source:
Purdue University
Summary:
Purdue University researchers have found that releasing a transgenic fish to the wild could damage native populations even to the point of extinction.

WEST LAFAYETTE, Ind. – Purdue University researchers have found that releasing a transgenic fish to the wild could damage native populations even to the point of extinction.

A transgenic organism is one that contains genes from another species. The Purdue research is part of an effort by Purdue and the U.S. Department of Agriculture to assess the risks and benefits of biotechnology and its products, such as genetically modified fish. The study was published in November in the Proceedings of the National Academy of Science.

Purdue animal scientist Bill Muir and biologist Rick Howard used minute Japanese fish called medaka to examine what would happen if male medakas genetically modified with growth hormone from Atlantic salmon were introduced to a population of unmodified fish. The research was conducted in banks of aquariums in a laboratory setting.

The results warn that transgenic fish could present a significant threat to native wildlife. "Transgenic fish are typically larger than the native stock, and that can confer an advantage in attracting mates" Muir says. "If, as in our experiments, the genetic change also reduces the offspring's ability to survive, a transgenic animal could bring a wild population to extinction in 40 generations."

Extinction results from a phenomenon that Muir and Howard call the "Trojan gene hypothesis." By basing their mate selection on size rather than fitness, medaka females choose the larger, genetically modified but genetically inferior medaka, thus inviting the hidden risk of extinction.

The transgenic medaka were produced by inserting a gene construct consisting of the human growth hormone driven by the salmon growth promoter into medaka. The viability of groups of modified and conventional fish were measured at three days of age, and 30 percent fewer transgenic fish survived to that age. The researchers calculated that large males had a four-fold mating advantage, based on observations of wild-type medaka. Computer models then were used to predict the consequences of the transgenic mating advantage combined with the reduced viability of the young.

The study represents scientists policing science, Muir says. "I hope people understand that scientists are investigating the risks of biotechnology as well as the benefits, so decisions can be made with as much information as possible. It's important to understand the risks so they can be addressed."

Muir also cautions that the results of his laboratory study should be interpreted conservatively. "The study does confirm there are significant risks to natural animal populations associated with the release of transgenic animals. We assumed a consistent environment with only one variable – sexual preference for size coupled with low life expectancy for the transgenic. The natural world is not nearly as orderly, and genetic background changes could negate the Trojan gene," he says.

The dominance of sexual preference over Charles Darwin's classic theory of survival of the fittest is not unknown to wildlife specialists and geneticists. Muir likes to use the example of the male bird of paradise with its long swells of gloriously colored plumage as an example: "The male bird of paradise with the longest, thickest tail attracts the most females. Subsequent offspring also exhibit the long tail and also compete well for females. Unfortunately, the birds with the biggest tails also have the biggest problem escaping predators who appreciate large birds pinned in place by their plumage. Obviously the bird with the most sex appeal is the also the worst choice as a fit mate. Not unlike high school, some might say."

The researchers' next goal is to replicate the study with larger fish of economic importance in a bigger environment. They're looking for an indoor swimming pool where they can raise tilapia and check the results of the medaka study.


Story Source:

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


Cite This Page:

Purdue University. "Transgenic Fish Could Threaten Wild Populations." ScienceDaily. ScienceDaily, 26 January 2000. <www.sciencedaily.com/releases/2000/01/000126080257.htm>.
Purdue University. (2000, January 26). Transgenic Fish Could Threaten Wild Populations. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2000/01/000126080257.htm
Purdue University. "Transgenic Fish Could Threaten Wild Populations." ScienceDaily. www.sciencedaily.com/releases/2000/01/000126080257.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Newsy (July 30, 2014) The Peace Corps is one of several U.S.-based organizations to pull workers out of West Africa because of the Ebola outbreak. Video provided by Newsy
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
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