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TITLE:  Biotech Crops' Crossbreeding Targeted
SOURCE: The Associated Press/The Washington Post, USA, by Randolph E. Schmid
        http://www.washingtonpost.com/wp-dyn/articles/A16856-2003May5.html
DATE:   May 5, 2003

------------------ archive: http://www.gene.ch/genet.html ------------------


Biotech Crops' Crossbreeding Targeted

WASHINGTON - Concerned that genetically modified plants will spread their
genes to related crops in nearby fields, researchers have developed a
system aimed at preventing such crossbreeding.

It's a method they hope, with further refinement, will allow farmers to
reseed crops yearly without worry about affecting nonmodified crops.

Biotech crops are a growing proportion of American agriculture. The
Agriculture Department estimates 38 percent of the corn planted this year
will be genetically engineered and 80 percent of soybeans will be a
biotech variety.

While American consumers generally seem to accept biotech foods,
Europeans doubt their safety. A European Union moratorium on U.S. biotech
imports has been in place for four years, costing the United States $300
million annually in corn exports.

And that ban raises concerns about biotech crops cross-pollinating
related plants in nearby fields, rendering those crops also unsuitable
for export.

The new system for preventing crossbreeding, developed by a team of
researchers led by Johann P. Schernthaner at Canada's Eastern Cereal and
Oilseed Research Center in Ottawa, is reported in the online edition of
Proceedings of the National Academy of Sciences.

While the system was developed using tobacco, Schernthaner said he
believes it would be applicable for most crops, although "the genetic
components involved would have to be assessed for suitability on a case
by case basis."

The findings do show, he said, "that the containment of transgenes is
possible in an agricultural setting and that environmental concerns ...
can be addressed in a simple fashion."

Doug Gurian-Sherman, science director for biotechnology at the Center for
Science in the Public Interest, said there "are pros and cons to this
from our perspective" but it is technology that should be explored as a
means of preventing gene movement.

"The big question is how it's applied," he said.

Agronomy professor T. Wayne Pfeiffer of the University of Kentucky said
that while the system worked to some degree, the process used seems
"impractical in a seed production system for a seed reproduced crop."

"The paper doesn't explain how the system would be maintained in 100
percent of the seeds in subsequent generations," he added, "so I do not
see this as a magic system to prevent the spread of transgenes in all crops."

In the Canadian research, the team first inserted a "seed lethality" gene
that prevents seeds of the plant from germinating, although the plants
had normal growth and seed production.

They then crossed this plant with another that had an added gene that
represses the seed lethality gene.

The offspring of the two produced a plant with viable seeds that could
continue to propagate indefinitely through self-pollination. But when
these plants were crossed with normal tobacco plants the seed lethality
gene and the suppressor gene were separated and the resulting seeds would
not grow.

While the system has been demonstrated in the laboratory, Schernthaner
and Steven Fabijanski, one of his co-authors, said it needs to be refined
and tested thoroughly for actual field use.

"In particular, the repression of the (seed-lethality) component would
have to be made watertight," they said.

In addition, they said a second genetic component probably is needed to
be sure of containing the repressor gene.

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On the Net:
Proceedings of the National Academy of Sciences: http://www.pnas.org
Agriculture and Agri-Food Canada: http://www.agr.ca