TL: SCIENTIFIC FINDINGS ON THREATS POSED BY GENETICALLY
ENGINEERED ORGANISMS (GEOS)
SO: GREENPEACE UK, (GP)
DT: 1996

A. GENETIC POLLUTION THROUGH POLLEN OR SEED DISPERSAL

* Gene transfer from crop radish to wild weedy relatives has
been detected over distances of one kilometre (Klinger et al.,
1992). Klinger and Ellstrand studied as well the fitness of
weed-crop hybrids (crossbreeds) of radish. The crossbreeds
showed significantly greater fruit and seed production, and in
all other measured characters the hybrids were like weeds. Their
results suggest that neutral or advantageous transgenes
introduced into natural population will tend to persist in wild
populations (Klinger & Ellstrand, 1994).

* Field tests with genetically engineered potatoes have
demonstrated both the high frequency and wide range of gene
flow. When normal potato plants were planted in distances up to
1100 metres from genetically engineered potatoes, and the seeds
of the normal potatoes were collected afterwards, 72% of the
plants in the immediate neighbourhood of the transgenic potatoes
contained the transgene. At greater distances an almost constant
35% of seeds contained the transgene (Skogsmyr, 1994).

* Scientists at the Scottish Crop Research Institute have shown
that much more pollen escapes from large fields of genetically
engineered oilseed rape than is predicted from earlier
experiments on smaller plots. They found that escaping pollen
fertilised plants up to 2.5 kilometres away (Timmons, 1994).

* Joergensen and Andersen (1994) showed how easily oilseed rape
crossbreeds with wild relatives and therefore how easily
transfer of the herbicide resistance gene could occur. Within
the first season they estimated that a substantial part of wild
weed population could acquire the gene for herbicide tolerance.
(Joergensen & Andersen, 1994, Mikkelsen,et al., 1996))

* Crop seeds travel hundreds of kilometres between seed
merchant, farmer and processing factory, therefore spillage in
transport is inevitable - and could be more worrying than threat
through pollen spread (Crawley, 1996).

B. THE RISK OF TRANSFER OF FOREIGN GENE TO MICRO-ORGANISM

It was reported in 1994 that gene transfer can occur from plants
to micro-organisms. Genetically engineered oilseed rape, black
mustard, thorn-apple and sweet peas all containing an
antibiotic-resistance gene were grown together with the fungus
Aspergillus niger or their leaves were added to the soil. The
fungus was shown to have incorporated the antibiotic-resistance
gene in all co-culture experiments (Hoffmann et al., 1994). It
is worth noting that micro- organisms can transfer genes through
several mechanisms to other unrelated micro-organisms.

This risk caused UK Environment Department's Biotechnolgy Unit
to advise the UK government to vote in the EU against the
authorisation for placing onto the market of Ciba Geigy's
transgenic corn in 1996: "the presence of an intact gene for
resistance to beta-lac tam antibiotics poses an unacceptable
risk because consumption of the unprocessed product as animal
feed could lead to the transfer of the gene to the gut
microflora of animals." Ciba Geigy's genetically engineered corn
contained among other foreign gene a gene for resistance against
Ampicillin antibiotics (beta-lac tam antibiotics).

C. NASTY SURPRISES

* Genetically engineered soil bacteria Klebsiella: A common
harmless variety of a bacteria Klebsiella planticola, inhabiting
the root-zone of plants had been genetically engineered to
transform plant residues like leaves into ethanol that farmers
could readily use as a fuel. The genetically engineered bacteria
not only survived and competed successfully with their parent
strain in different soil types, it proved unexpectedly to
inhibit growth or kill off grass in different soil types tested.
In sandy soil, most of the grasses died from alcohol poisoning.
In all soil types the population of beneficial mycorrhizal fungi
in the soil decreased. These soil fungi are crucial for plant
health and growth as they help plants to take up nutritions and
to resist common diseases. In clay soils, the genetically
engineered bacteria increased as well the number of root-feeding
nematodes. (Holmes and Ingham, 1995)

* Genetically engineered salmon: The transgenic salmon was
engineered with an arctic flounder gene for increased cold
tolerance. However, this transgenic salmon grows ten times as
fast as normal salmon as the genetic modification resulted in an
increased activity of the salmon's own growth hormone gene
(MacKenzie, 1996).

* The bacteria Pseudomonas putida was genetically engineered to
degrade the herbicide 2,4-D. The engineered bacteria broke down
the herbicide but degraded it to a substance that was highly
toxic to fungi. These fungi - crucial to soil fertility and in
protecting plants against diseases - were therefore destroyed
(summarised in Doyle et al., 1995).

* The toxin-producing gene of the bacteria Bacillus
thurigiensis, for instance, is commonly engineered into crops to
provide them with a built-in insecticide. However, the toxin
produced is known to resist degradation by binding itself to
small soil particles whilst continuing its toxic activity. The
long term impact of this toxin on soil organisms and soil
fertility is unknown (summarised in Doyle et al., 1995).

D. DEADLIER VIRUSES

Genetically engineered virus resistant crops may cause the
development of new kinds of plant viruses due to recombination
events. Scientists published a study demonstrating that virus
genes implanted into plant cells could be transferred into the
genome of other viruses that the plants come into contact with
(Greene and Allison, 1994). This could lead to the unintentional
creation of new, and perhaps more virulent, plant viruses.

E. ALLERGIES

A new study showed that genetically engineered soybeans
containing one foreign Brazil nut gene could cause allergic
reactions in Brazil nuts sensitive humans (Nordlee et al.,
1996).

The discovery of the allergenic potential of Pioneer's
genetically engineered soybean prior to its use as human food
sources was thanks to a unique advantage: the donor organism for
the gene, Brazil nut, was a known food allergen, and serum
samples of persons known to be allergic to brazil nuts were
available for testing. However, in many cases it is not genes
from long known food plants that are transferred into crops.
Genes from bacteria which have never been part of the diet are
more common components. This is the case with Monsanto's RRS.
Who knows what the allergenic potential of this newly introduced
gene product will be? It is uncertain, unpredictable and
untestable (Nestle, 1996).

REFERENCES

Crawley M (1996) 'The day of the triffids'. New Scientist 6 July
pp 40-41

Doyle JD, Stotzky G, McClung G & Hendricks C W (1995) Effects of
Genetically Engineered Microorganisms on Microbial Populations
and Processes in Natural Habitats, Advances in Applied
Microbiology, Vol. 40 (Academic Press)

Greene, A.E. and Allison, R.F. (1994) Recombination between
viral RNA and transgenic Plant Transcripts, Science Vol. 263, 11
March 1994

Hoffmann T, Golz C & Schieder O (1994) Foreign DNA sequences are
received by a wild-type strain of Aspergillus niger after
co-culture with transgenic higher plants. Curr. Genet. 27:
70-76.

Holmes T M & Ingham E R (1995) The effects of genetically
engineered microorganisms on soil foodwebs. in "Supplement to
Bulletin of Ecological Society of America 75/2, Abstracts of the
79th Annual ESA Meeting: Science and Public Policy" Knoxville,
Tenesse, 7-11 August 1994.

Joergensen R B & Andersen B (1994) Spontaneous Hybridization
between Oilseed Rape (Brassica napus) and Weedy B. Campestris
(Brassicaceae): A risk of growing genetically modified oilseed
rape. American Journal of Botany, 81(12), p. 1620-1626.

Klinger T and Ellstrand N C (1994) Engineered Genes in Wild
Populations: Fitness of Weed-Crop Hybrids of Raphanus sativus.
Ecological Applications Vol.4, No 1: 117-120

Klinger T, Arriola PE & Ellstrand NC (1992) Crop-weed
hybridization in radish (Raphanus sativus L.): Effects of
distance and population size. Am. J. Bot. 79: 1431-1435.

MacKenzie D. (1996) Altered salmon grow by leaps and bounds, New
Scientist, 6 January 1996

Mikkelsen T R., Andersen, B., and Jorgensen R. B. (1996) The
risk of crop transgene spread, Nature Vol 380, 7 March 1996

Nestle M (1996) Allergies to transgenic foods - question of
policy, The New England Journal of Medicine, Vol 334, No 11:
726-728

Nordlee J A, Taylor S L, Townsend J A , Thomas L A and Bush R K
(1996) Identification of a brazil-nut allergen in transgenic
soybeans, The New England Journal of Medicine, Vol 334, No
11:688-692

Skogsmyr I (1994) Gene dispersal from transgenic potatoes to
conspecifics: A field trial. Theor. Appl. Genet. 88: 770-774.

Timmons AM, O'Brien BT, Charters YM & Wilkinson MJ (1994)
Aspects of environmental risk assessment for genetically
modified plants with special reference to oilseed rape. Scottish
Crop Research Institute, Annual Report 1994. SCRI, Invergowrie,
Dundee, Scotland