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Gene Flow

Note: DuPont scientists conducted a review of current scientific literature related to gene flow between crop varieties and gene flow from crop to wild relatives. This information will be updated from time-to-time. We welcome new scientific information and, of course, your perspective.

Unintended cross-pollination of different cultivars of a crop can sometimes occur with commercially improved varieties, developed through conventional breeding or biotechnology, or with landraces, which are locally adapted varieties derived from thousands of years of seed selection by farmers

The seed industry follows internationally determined and accepted standards for genetic purity. These standards call for the use of specific distances between fields to manage gene flow. These distances are necessary to meet the standards for purity.

The seed industry is applying the lessons learned from working with these standards, as well as our own experiences, to understand and manage gene flow issues related to crops derived through biotechnology. In addition to using isolation distances before marketing these crops, we surround the field with a number of border rows of non-biotech plants that serve as pollen-catchers. This reduces the chances for cross-pollination. In spite of the many measures we use during seed production to minimize the presence of biotech genetic material in non-biotech seed batches and vice versa, it is recognized by many that trace amounts of biotech genetic material or seeds may be found in some fields containing non-biotech varieties.

Gene flow naturally occurs between plants, and has occurred between crops and compatible relatives since the first cultivation of crops.  Gene flow can also occur between transgenic plants and wild relatives, however gene flow may only be viewed as significant if the transgenic trait is actually transferred to the wild relative and imparts some type of advantage to that plant. The likelihood of these events occurring together is small. Nevertheless, the seed industry is working on new methods for controlling gene flow from transgenic crops.