Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Purdue scientists: Genetically modified fish could damage ecology


The genetic modifications that improve animals for human consumption also could doom populations if released into the wild, according to a Purdue University research team.

Biologist Rick Howard and his colleagues have discovered a paradox that crops up when new genes are deliberately inserted into a fish’s chromosomes to make the animal grow larger. While the genetically modified fish will be bigger and have more success at attracting mates, they may also produce offspring that are less likely to survive to adulthood. If this occurs, as generations pass, a population could dwindle in size and, potentially, disappear entirely.

"Ours is the first demonstration that a genetically modified organism has a reproductive advantage over its natural counterpart," said Howard, a professor of biological sciences in Purdue’s School of Science. "Though altering animals’ genes can be good for humans in the short run, it may prove catastrophic for nature in the long run if not done with care. And we don’t know just what kind of care is necessary yet, or how much."

This research, which Howard conducted with William Muir of the animal sciences department and Andrew DeWoody of the forestry and natural resources department, appears in this week’s (Feb. 17) online issue of the journal Proceedings of the National Academy of Sciences. Howard and Muir published a related article in the same journal in December 1999 that showed larger animals had a mating advantage, but their previous article did not relate mating advantage to genetic modification (see below URL for related news release).

The most common question posed about genetically modified organisms – GMOs for short, and also called transgenics – is whether they are safe for people to eat. When GMOs were first made commercially available in 1996, many food crops, such as corn and soybeans, were altered to produce substantially more yield than they do in nature. The debate on GMOs in supermarkets has not yet been resolved, and Howard said it could be drawing attention from an equally important issue: whether GMOs are safe for the planet.

"With all the concern over whether transgenic food is safe for humans, the environment has been more or less left out of the picture," Howard said. "Plenty of laboratories are studying whether GMOs are safe for human consumption, but to my knowledge, ours is the only one that looks at whether they will be safe for the Earth."

As a step toward resolving this issue, Howard and his colleagues set out to examine the risk transgenic fish might pose to natural-bred populations. They chose to examine the Japanese medaka, a small fish that breeds daily, because it would reproduce often enough for trends to emerge relatively quickly.

"We took several tanks and put a female into each one with two males – one natural, and one transgenic," Howard said. "The transgenic males were 83 percent heavier than the natural-bred males, so it was easy to distinguish which male was mating with the female."

Howard found that the larger transgenic males mated three times for every time the natural-bred males did – not surprising, considering the premium that female medakas place on male size. But though the transgenic males mated more often, fewer of their young survived to adulthood.

"What surprised us was how fast a GMO mating advantage could cause a transgene to spread in a population," Howard said. "Additionally, we were intrigued at the outcome predicted if this advantage was combined with the disadvantage of young with reduced survival ability."

Howard observed that for every 100 offspring sired by a natural male that survived to adulthood, only 70 of the young produced by a transgenic male survived.

"Putting both of these things together, a population invaded by a few genetically modified individuals would become more and more transgenic, and as it did the population would get smaller and smaller," he said. "We call this the ‘Trojan gene effect.’"

Over time, continued Howard, this effect could continue to multiply itself over generations, eventually decimating a population.

"Imagine a pie, and you eat 30 percent of it every day," he said. "Half of it is gone in two days, and within a week less than one-tenth of it remains. It is conceivable that a similar effect could occur among fish populations if GMOs with ‘Trojan genes’ escape into the wild."

Though the report’s conclusions are sobering, Howard cautions that the group’s research is based on computer models as well as observation of actual fish mating behavior – behavior that took place within a controlled laboratory setting rather than in nature, where other factors could influence the outcome. Consequently, these ideas should not be taken as gospel under all circumstances.

"We were aiming to detect the potential risk a GMO might pose to the environment," he said. "The protocols our group developed with this report could be used as a tool for agencies and food producers for that purpose."

This research has been funded in part by the U.S. Department of Agriculture.

Writer: Chad Boutin, (765) 494-2081,
Source: Rick Howard, (765) 494-8136,
Purdue News Service: (765) 494-2096;

Chad Boutin | Purdue News
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>