Gene flow and risk assessment

The primary aim in assessing the amount of gene flow from higher plants, in the context of risk assessment of the release of GMO's, is to obtain an es timate of the distribution of the dispersal stages (e.g. pollen and seeds). A knowledge of this distribution will then permit estimation of the probab ility of the dispersal stage travelling further than a specified distance f rom its source. Such cumulative dispersal probabilities,can then be used to design both any appropriate confinement measures for a release and monitor ing procedures to ensure the efficacy of the confinement. A standard statistical method for analysing gene-flow data is described and applied to data obtained from crop plants or their relatives, previously p ublished in the scientific literature. The concept of relative risk is deve loped and applied to this data. Attention is drawn to the inherent variabil ity of both gene flow and its estimates in these experiments and to the con sequent problems in attempting to quantify risk to the environment.