Possible risks of GMO-s

1. Possible risks of GMO-s • Creating new, and more vigorous pests and pathogens • Exacerbating the effects of existing pests through hybridisation with related transgenic organisms • Harm to non-target species • Disruption of biotic communities, including agro- ecosystems • Irreparable loss or changes in species diversity or genetic diversity Therefore some GMO-s require greater scrutiny than organisms produced by traditional techniques of breeding (ESA Report, Snow et al., 2005, Ecol. Appl., 15, 377-404.)

2. GMO-s posing some risks to the environment • Little or no prior experience with the trait and host combination • GMO-s may proliferate and persist without human intervention • Genetic exchange possible between a transformed organism and non-domesticated organisms • Trait confers an advantage to the GMO over native species in a given environment (ESA Report, Snow et al., 2005, Ecol. Appl., 15, 377-404.)

3. Guidelines for GMO creation and release • Early planning and design of GMO-s to reduce environmental risks (reduce risks of sterility, lower fitness, • The promoter should be inducible rather than constitutive • Selection markers should be removed before cultivation • Prevent large-scale or commercial releases if scientific knowledge exist about possible risks • Post-release monitoring to detect environmental risks • Thorough risk-assesment, expertsts should have multidisciplinary training

4. TRANSGENES • Create organisms with traits that cannot be obtained through normal sexual reproduction • Novel, synthetic genes that have never existed in nature • Minimally they are composed of a gene sequence flanked by a promoter and other elements that may come from different organisms • Phenotypic characteristics, such as size, health, reproductive capacity are determined by complex interaction among its genes and its surroundings, and cannot be characterized in small-scale experiments (ESA Report, Snow et al., 2005, Ecol. Appl., 15, 377-404.)

5. Benefits Facilitate no-tillage/low-tillage weed management Conserves topsoil and soil moisture, reduce erosion Allows greater carbon sequestration in soil organic matter Glyphosate breaks down more quickly and is more „environmentally friendly” than many other herbicides Caveats Glyphosate is the most widely used herbicide in the US Its use may not be sustainable if weeds shifts occur to favor glyphosate-tolerant weeds or weeds develop tolerance to glyphosate New alternatives to glyphosate-tolerant crops may be too expensive or difficult for chemical companies to develop and commercialize Herbicid-tolerant crops(ESA Report, Snow et al., 2005, Ecol. Appl., 15, 377-404.)

6. Benefit Can reduce the use of broad-spectrum insecticides Caveats May not be suistainable if secondary pests become more problematic and/or if target pests evolve resistance to the Bt crop Above ground, broad-spectrum insecticides are not applied to most of the US corn acreage Higher lignine content (Saxena and Stocky, 2001) Bt-transgenic plantsESA Report, Snow et al., 2005, Ecol. Appl., 15, 377-404.)

7. Benefit Could reduce the use of fungicides and insecticides that currently are used to kill disease-vectors, or disease-causing organisms Caveats May noy be suistainable if pathogens evolve resistance to transgenic varieties Few crops with transgenic disease resistance have been deregulated to date (exceptions include virus-resistant squash, papaya and potatoes) GM crop-plants with transgenic resistance to common diseasesESA Report, Snow et al., 2005, Ecol. Appl., 15, 377-404.)

8. Benefit Higher yield per acra could reduce pressure on natural areas because less area needs to be cultivated for a given amount of yield Caveats Higher yield per area could be an incentive to cultivate transgenic crops on larges areas Evidence for yield gains above current production levels are not well documented as yet GM crop-plants with higher yields due to one or more transgenic traitsESA Report, Snow et al., 2005, Ecol. Appl., 15, 377-404.)

9. Benefit More effective and less expensive clean-up of toxic vaste sites than with current methods Caveat Early in development, not known if effective in the field or economically viable Mediation of polluted soil using transgenic plants or bacteriaESA Report, Snow et al., 2005, Ecol. Appl., 15, 377-404.)

10. Benefit Leaner paper milling and less pollution of waterways Caveat Early in development, not known if commercially viable Decreased lignin production in transgenic, commertial tree plantationsESA Report, Snow et al., 2005, Ecol. Appl., 15, 377-404.)

11. Transformation of plant cells • Using a disease causing pathogen, Agrobacterium tumefaciensis (for dicotyledonous plants) • Particle bombardement ( mostly for monocots) • Physical methods • Chemical methods The transformation process is very inefficient (Birch, 1997) Transgene is linked to a selectable marker, encoding herbicid-resistance antibiotic-resistance

12. UNINTENDED PHENOTYPES • Position effects • Random chromosomal locations, often at multiple sites • DNA sequences may interrupt native genes, or promoter sequences that regulate them • Can bring about small-scale rearrangements of the transgene and native DNA sequences at the insertion site (Pawlowski and Somers, 1998, Svitasev et al, 2000, 2002, Windels et al, 2001) • Interaction among the transgene and native genes (Hartman et al, 2001) • Pleiotropic effects of transgenes - small, unintended effects may remain undecetcted, they may depend on cumulative action, environmental conditions Introgression into different genetic backgrounds

13. Virus-resistant crops • Beachy et al. (1990) discovered the general principle, that the coat protein of a virus could provide resistance to the same virus • Potential ecological risks of virus-resistant crops: • Benefit of transgenic virus over wild type • Recombination between viral transgenes and invading viruses (Power 2002, Tepfer 2002 • Interaction between an invading virus and the viral RNA encoded by transgenes (Miller et al, 1997, Aziz and Tepfer 2002, Power 2002, Hammond et al, 1999)

14. Virus-resistant crops • Hazards of virus – transgene recombination • increased virulence • alterations to host range • change of transmission characteristics (Schoelz and Wintermantel 1993, Kiraly et al. 1998, Borja et al. 1999, de Zoeten, 1991, Miller et al 1997) • Transcapsidation (encapsidation of viral RNA of one virus by the coat protein of another virus in mixed infections (Power 2002, Tepfer 2002), even if at low rates (Thomas et al, 1998, Fuchs et al, 1999) • Synergistic interaction between viruses in mixed infections (Miller et al, 1997)

15. HORIZONTAL GENE-FLOW • 1-20% of an organism derives from foreign DNA (Ochman et al, 2000, Koonin etal, 2001) • Major source of microbial evolution • Depends on population density • Less frequent between distantly related taxa • Most likely to occur, and had been detected in microbial communities (Gebhart and Smalla, 1998, Nielsen et al, 1998, Bertolla and Simonet 1999, Kay et al, 2002)

16. Gene flow • Transgenes are inherited and have the potencial to disperse (Quist and Chapella, 2001, 2002, Beckie et al, 2003) • Crop to crop • Crop to wild (Ellstrand et al. 1999,2003, and Messeguer, 2003) Fitness transgenes conferringresistance has an effect on plant population dynamics (Power, 2002, Mitchell and Power 2003, Callaway et al. 2004, Snow et al. 2003)