Professors create a model
to evaluate environmental risk
By Ian Clift
Summer Reporter
Two Purdue professors have developed a model to
assess the environmental risk posed by genetically modified organisms.
Scientists have searched for the mechanisms that
cause organisms to be successful or unsuccessful in nature, said William
Muir, professor of animal science. "In our research it really doesn't
matter what causes the effect, what our results do is take it down to
a science."
Muir and his associate, Richard Howard, professor
of biological sciences, have determined six factors to measure whether
a transgenic population will spread in the wild.
"One of the things you would ask is what is (the
organisms) viability at sexual maturity," said Muir. But there are other
factors that must be looked at once an organism gets to sexual maturity.
The six factors are sexually viability, mating
success, offspring number, male fertility, the age of maturity and average
longevity.
Previously, many scientists were testing only one
of the six traits to determine a transgenic organism's environmental
spread risk.
The model, funded by the U.S. Department of Agriculture's
Biotechnology Risk Assessment Program, was designed to test risk posed
by genetically modified fish, but can be expanded to include most genetically
modified animals and plants.
Their results were published in the July issue
of The American Naturalist.
Transgenic organisms can be advantageous in increasing
food supply and industry profits, said Muir. "We just want to be certain
that it doesn't have hidden costs."
"When DDT first came out it was thought to be the
savior of mankind," said Muir. "It wasn't until 20 years later that
we found that it had a huge environmental cost."
Howard said, "I think a lot of the concerns are
based on misinformation, or lack of information. (People) are tending
to imagine worse case scenarios. What is really needed is a test."
The model is fairly accurate in determining the
results these organisms will have on wild organisms. Muir said, "We
can't predict exactly what will happen in the future."
Tests can only be conducted in the laboratory.
"If the model predicts exactly that (the population) will not spread
then we are very confident that it won't spread in nature," said Muir.
"There are cases that appear to be risky and those are the cases that
you need to take extra precautions with."
Howard said, "The next step is to see if the predictions
of the model actually occur or not."
"For example if we have one line of transgenic
fish that the model suggests should increase in frequency in the population
of wild fish, does that actually occur or not."
The model, which is based on population genetic
theory, should help to ease concerns over the use and production of
genetically modified organisms.
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