Altering Genes-A Mortal Threat to the Ecosystem?

Alter Genes, Risk an Ecosystem?

By Marc Kaufman
Washington Post Staff Writer
Monday, June 4, 2001; Page A07

As the jaguar hunts at dusk in the jungle, the spots it has developed over
the millennia help camouflage it from its prey. When a baby crocodile is
born, it immediately knows to lunge out of the water for insects but will
avoid dead ones on the water surface or sinking to the river floor.

Darwinian survival of the fittest has long explained these kinds of
adaptations. But the advent of genetic engineering has prompted scientists
to analyze further the links between the genetic structure of life-forms and
the environments in which they live. In addition to the environment spurring
genetic changes in jaguars, crocodiles and other living things, do the genes
of animals, plants and insects affect the world that surrounds them in more
complicated ways?

This theoretical question has particular urgency because of the ongoing and
increasingly heated international debate over agricultural biotechnology.
The process by which the modified genes of plants (or fish or insects) might
affect the environment is suddenly a hot topic, and researchers on all sides
are weighing in.

That the human genome project has found far fewer genes than initially
expected has added to the debate by making it clear that genes by themselves
may not have the enormous diversity needed to account for the full range of
human traits and behaviors. Rather, genes must interact with the
environment, and among themselves, to produce the traits that distinguish a
person from a chimpanzee or an earthworm, or one person from another.

The genome of an organism is a complex and dynamic environment unto
itself. Any analysis of how genetically altered organisms will affect the
environment must take into account all the ways in which the traditional
"outside" environment interacts with the newly recognized and equally
complex "internal" genetic environment, some scientists suggest.

In an essay that is being embraced as an important philosophical advance by
some environmentalists, Arjun Makhijani of the Institute for Energy and
Environmental Research in Takoma Park has put some of these ideas together
into a broadside against genetic engineering. He argues that the
relationship between the genetic material of living things and the
ecosystems in which they live is deep and changeable, and that tinkering
with genes may upset the environment -- and plants and animals in that
environment -- in far more complicated and far-reaching ways than have been
considered.

"My hypothesis is that the genome is an internal expression of the ecosystem
in which it lives," Makhijani said. "If individual genomic structures are so
intimately connected with their ecosystems, then it makes sense that messing
with genomes would have an effect on . . . the entire ecosystem."

He concludes that products such as corn genetically engineered to repel
insects -- a process that involves the addition to the corn seed of a gene
from bacteria that naturally perform that task -- are inherently more risky
to the surrounding ecosystems than conventional corn. Genetic engineering,
he argues, will have much broader effects than have generally been
appreciated because it involves the combination of genes from disparate
organisms such as bacteria and corn that would not normally share their
genomes.

While some of the changes may be benign, Makhijani points to recent
Australian efforts to genetically engineer a mousepox virus to control
rodents and crop damage as an example of the dangers.

The goal was to increase the immune response of the rodents so female mice
would reject their own eggs as foreign objects. Unexpectedly, however, the
opposite happened, and the genetically engineered virus suppressed the
immune system in lab mice. The experiment created a new kind of supervirus
that, if it had been introduced into the environment, could have set off a
cascade of potentially devastating changes.

Richard Strohman, an emeritus biology professor at the University of
California at Berkeley, has explored similar ideas and believes that the
general environmental risks of biotech crops have not been fully examined.

"There's been so much focus on how one gene might cause one particular
trait," said Strohman, who serves on a panel at the University of
Pennsylvania Center on Bioethics examining ethical issues of genetically
engineered crops. "But there's no real discussion of the more complex issue
of how genes are changed by natural selection in the environment and how
that might be affected by genetic engineering."

In a report last year that was generally supportive of genetic engineering
of plant crops, the National Academy of Sciences' National Research Council
also highlighted the need for more research into these long-term ecological
effects.

Human agriculture has, of course, modified plants for centuries and caused
vast changes in the environment. Virtually none of the crops grown in the
United States are native, and all have been crossbred to a great degree.

In a recent article in the journal Plant Physiology, Channapatna S. Prakash
of the Center for Plant Biotechnology Research at Tuskegee University wrote
that while "gene flow" from crops such as engineered corn is a legitimate
concern, the potential environmental harm is minuscule when compared with
the fact that corn -- a species not native to the United States -- is now
grown here on 75 million acres. In addition, Prakash writes, modified corn
includes one or two genetically engineered genes out of 50,000.

"Plants produced through the crossbreeding of genetically engineered crops
and their wild relatives are few and very unlikely to compete successfully,"
he said. "I don't see any empirical evidence that says gene flow from
genetically engineered crops confers different risks than gene flow from
conventional crops."

Fears about gene flow have been "orchestrated by people who don't like
biotech or have a vested interest, like organic farmers," he said.

Val Giddings of the Biotechnology Industry Organization said that today's
movement of genes from one life-form to another is not problematic and that
it is actually how all species alive today came to be what they are.
Biotechnology allows the process of change -- the introduction of mutations
into existing species -- to be far more predictable and controlled than
ever, he said.

Norman Ellstrand, a professor of genetics at the University of California at
Riverside, has been studying the extent and dynamics of gene flow in crop
plants such as radishes and sorghum. This unintentional crossbreeding with
wild relatives is considerably more common than earlier believed, he has
found, and has been associated with the evolution of more aggressive weeds
for seven of the world's 13 most important crops.

"Are [genetically engineered] crops likely to be different from
traditionally improved crops?" he asks. "No, and this is not necessarily
good news. It is clear that the probability of problems due to gene flow
from any individual [plant] is extremely low, but when those problems are
realized, they can be doozies."

In fact, Ellstrand wrote that he was aware of at least three cases in which
scientists decided not to engineer certain traits into crops because of
concern about what gene flow might do to nearby crops and weeds.

The possible environmental effects of agricultural biotechnology have gotten
most attention regarding monarch butterflies and corn engineered to contain
a protein from Bacillus thuringiensis (Bt) bacteria, which naturally kill
insects. A 1999 report in the journal Nature raised the possibility that,
based on lab tests, the larvae of monarch butterflies could be harmed if
pollen from Bt corn blew onto nearby milkweed plants where they feed.

That report caused scientific concern, but subsequent research has generally
minimized the actual damage that will be caused to monarchs in and around
the Midwest cornfields where larvae grow and feed.

The question of containment was one that initially led Makhijani, a
physicist trained in controlled thermonuclear fusion and a longtime critic
of the nuclear industry, to examine biotechnology and the environment.

"Both technologies offer enormous possibilities but come with inherent
risks," he said. "With both, we are making changes in nature that cannot be
recalled or undone."