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Genetic crops and weeds, archive 187

With respect to the following press release:

>GENETICALLY-ALTERED CROPS CAN PRODUCE TOUGH, HARD-TO-KILL WEEDS
>Aug. 6/98
>Ohio State University press release
>

>"When a crop grows near its weedy relative, it's inevitable that the
>genetically-engineered trait will move into the weed," said Allison Snow,
>associate professor of plant biology at Ohio State. ......

Rick notes:

NOT all crops can cross with their weedy relatives, eg. cultivated potatoes
cannot cross with North American weedy plants of the same genus, Solanum.
As in this case, most if not all of the stories you'll see are about rape,
where there is genuine concern.




>Snow said that she and her colleagues would have to study oilseed rape and
>Brassica rapa in the field to fully gauge the benefits of herbicide
>resistance in the weed.

Rick notes:

One study has already done in the UK; see Nature vol 393, 28 May 1998, page 320.

>
>"I don't like to paint this as an emergency, or as a disaster waiting to
>happen. I just think it's important to understand what we're doing when we
>create transgenic crops, and delay the possible negative consequences, if
>not prevent them in the first place," said Snow.



>
>One solution might be for scientists to insert genetically-engineered
>traits into the DNA of the cytoplasm of plant cells, instead of the
>nucleus. The DNA from the nucleus gets into every pollen grain of a plant,
>and will travel far and wide on the wind, or hitch a ride with pollinators
>such as bees. But a gene in the cytoplasm could only be inherited through
>the seeds of a particular plant.

Rick notes:

Snow appears to be out of date (and not read up on the literature) on this
one; expression only in cytoplasm will probably slow but may not stop
spread.  Most importantly, this system does not stop weedy hybrids where
the weed is the pollen donor.  Some genes in cytoplasm can also be passed
through pollen.  See Nature Biotechnology Volume 16 May 1998, page 401 (see
also the adjacent letters from and concerning John Fagan).

>
>In the future, Snow wants to study transgenes for insect-resistance. "We
>want to quantify how much of a benefit there is to a weed that acquires
>these transgenes," she said. "It's a very basic ecological question, but
>nobody knows the answer."

Rick notes:

Out of date again.  It's being looked at.


Rick
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