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June 8, 2009
by Kimani Chege,
SciDev.Net
Scientists have unveiled a new way
of altering the genetic sequence of a crop to produce a desired
trait without needing to introduce foreign genes.
The technique could be less controversial than conventional
genetic modification because it does not involve transferring a
gene from another species.
Scientists used a set of enzymes to "subtly change" a tobacco
plant's DNA to make it herbicide resistant.
The enzymes — known as zinc finger nucleases — can be engineered
in the lab to target specific genes, introducing changes known
to cause the desired trait.
Until now there has been no efficient way of making such changes
to plant genes.
Daniel Voytas, director of the US-based
University of Minnesota Center
for Genome Engineering and the lead author of the research says:
"We changed a few letters in the genetic code of a native plant
gene and made the plant resistant to herbicide. In most
genetically modified crops, herbicide resistance is conferred by
adding a foreign gene, usually from bacteria."
The researchers hope the technique will revolutionise how crops
are genetically modified.
"We need to test this technology and compare it with traditional
methods of gene transfer. I think ... precise DNA sequence
modifications that do not introduce foreign DNA will be
preferred over traditional approaches," Voytas told SciDev.Net.
Voytas says the technique requires only standard molecular
biology laboratories and competence in introducing DNA into
plants — resources that are available in many parts of the
developing world. He also says capacity to do such work should
be increased in developing countries.
Kamonji Wachiira, an environmental consultant based in Ottawa,
Canada, says the technique sounds promising but seems to be
largely untested.
There are also concerns about its effectiveness, and the usual
biosafety issues associated with genetic modification, says
Wachiira. He adds that the zinc finger nucleases could have
unpredictable effects on several genes. "The new trait may well
be accompanied by latent, recessive or unintended but risky
traits."
The research was published in April in
Nature.
Full article in Nature:
High-frequency modification of plant genes using engineered
zinc-finger nucleases |
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