Transgenic Plants - Introduction Ecological risks

The potential impact on nearby ecosystems is one of the greatest concerns associated with transgenic plants. Transgenes have the potential for significant ecological impact if the plants can increase in frequency and persist in natural populations. This can occur:

    * if the transgene escapes from the fields into the wild.
    *  if transgenic plants mate with similar wild plants, the transgene could be incorporated into the offspring.
    * if these new transgene plants become weedy or invasive, which could reduce biodiversity and might destroy entire ecosystems.

There are three possible avenues of hybridization leading to escape of a transgene:

   1. Hybridization with non-transgenic crop plants of the same species and variety.
   2. Hybridization with wild plants of the same species.
   3. Hybridization with wild plants of closely related species, usually of the same genus.

However, there are a number of factors which must be present for hybrids to be created:

    * The transgenic plants must be close enough to the wild species for the pollen to reach the wild plants.
    * The wild and transgenic plants must flower at the same time.
    * The wild and transgenic plants must be genetically compatible.
    * The hybrid offspring must be viable, and fertile.
    * The hybrid offspring must carry the transgene.

Studies suggest that the most likely escape route for transgenic plants will be through hybridization with wild plants of the same species.

   1. It is known that some crop plants have been found to hybridize with wild counterparts.

   2. It is understood, as a basic part of population genetics, that the spread of a transgene in a wild population will be directly related to the fitness effects of the gene in addition to the rate of influx of the gene to the population.  Advantageous genes will spread rapidly, neutral genes will spread with genetic drift, and disadvantageous genes will only spread if there is a constant influx.

   3. The ecological effects of transgenes are not known, but it is generally accepted that only genes which improve fitness in relation to abiotic factors would give hybrid plants sufficient advantages to become weedy or invasive.  Abiotic factors are parts of the ecosystem which are not alive, such as climate, salt and mineral content, and temperature.

source : hydroponicsearch