Purdue scientists study
risks of gene alteration
By Lori Kohls
Staff Writer
Worries about genetically modified organisms may
soon be relieved through work of two Purdue scientists.
Richard Howard, professor of biology, and William
Muir, professor of animal sciences, worked together to develop a model
to determine the risks related to genetically modified, or transgenic,
organisms.
"It's used to see what would happen if they got
out into the wild; if they would live and could breed," said Howard.
Funded by the U.S. Department of Agriculture's
Biotechnology Risk Assessment program, the model originated to determine
the environmental risk of genetically modified fish, but has expanded
to include all sexually producing modified plants and animals.
Genetically modified organisms can have many advantages,
such as increasing food supply and profits. They can also make food
taste better or be healthier. For instance, yellow rice has vitamin
A added genetically and modified tomatoes stay ripe longer.
It is important though, to assess hidden costs
of these organisms before they are introduced into the environment,
and that is the goal of this model.
The model looks at six characteristics related
to survivorship and ability to reproduce, and uses them to determine
to what degree the modified gene may spread. These characteristics include
juvenile and adult viability, age at sexual maturity, female and male
fertility, and mating success. By comparing these traits, the model
can predict problems that may occur in the population.
"If transgenic males have high mating success and
produce offspring that are not viable, that can cause a problem," said
Howard.
A limitation with this type of research is that
it is not possible to directly test it. Scientists can only go so far
in trying to predict what would happen in the wild.
"We can't put transgenically modified fish into
the ocean and watch what happens," said Howard, "but we know the gene
is likely not to be a risk if it doesn't spread."
The model predicts the risk of the gene spreading,
but cannot predict the hazard or adverse effects of the spread. Muir
said, "The only way to eliminate detrimental effects of the hazard in
the gene spread is if it doesn't spread at all."
Although it is hard to determine the consequences
of a gene that is likely to spread, it is even more difficult to predict
the effects of that gene in relation to other species. The intricate
food web on earth has species interconnected in ways that can't be foreseen.
"Our transgenically modified organism may affect
one species, which in turn affects another," said Muir. "This cascading
waterfall effect makes it nearly impossible to get that all into a model."
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