Trojan genes

This is a very interesting and early article about the risks of GMO fish which draws attention to the blog about Frankenfish being allowed to sold for human consumption- see Frankenfish. 

Just be because we can modify organisms to creae some changes that suit our needs does not mean the changes are good for the organisms in the wild.

Biologist Rick Howard and his colleagues at Purdue University have identified a paradox that appears when genes to make a fish grow larger are spliced into the fish’s chromosomes . While the GM fish will grow larger and faster  it will also have greater mating success, these "frankenfish" could produce offspring that may die before they reach sexual maturity. If this were to occur over some generations, the population would decrease and eventually disappear entirely.  This has direct evolutionary impacts on the populations of fish.   Option E 5 -Sexual selection of exaggerated traits could be discussed here.  Females typically prefer larger males as mates.  Despite the selection for male size as more successful mates, the reduced reproduction would condemn the future generations of fish.

"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." ^[1]

Many people are concerned about whether or not genetically modified organisms are safe for people to eat. The first GMO crops such as soybeans and maize appeared on the market in 1996 and were made to produce substantially more yield than they do in nature or to grow in the presence of herbicides.  The  debate about  the safety of GMO's to humans clouds the picture of whether GMO's are safe for the ecology of the world.

"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." (Boutin, 2010)

Howard investigated the potential harm transgenic fish might have against natural populations.  Building on from Darwin's lesson that species tend to over reproduce and thus create a struggle for survival, they bred the Japanese medaka, a species that repoduces daily, as it would produce so many offspring that  trends would show up relatively quickly.  Investigations with larger GM and smaller normal males allowed the researchers to observe which male mated with the female medaka.  The larger males mated more often with the females but their offspring were less likely to reach adult status.  The variation of size is inherited as is the survivability of offspring. The selection of larger males was significant, but there is the Trojan gene- lower survivability of offspring.  Dr. Howard does recognize that his study, based on lab settings, may not represent true fish behaviour in the wild but the results do suggest that transgenic organisms that escape to the wild may represent a danger to the wild population.  The precautionary principle, covered in topic 5.2 Greehouse effect, could be considered with students using this article.