There is a popular perception that genetic engineering (GE, GM, GMO) is just a development of plant breeding techniques that have been practiced since the dawn of civilisation. No honest scientist would make this claim.
Conventional breeding transfers genetic information between related organisms - members of the same species or, rarely, of closely related genera. Genetic engineering, however, overcomes the barriers that have existed for three billion years of evolution and now transfers genes between unrelated species, genera or kingdoms. For example, a potato may now carry the gene that stops a fish freezing.
Gene transfers aim at certain results, but the process relies on trial and error. Occasionally the transferred gene seems to have the desired effect in the host organism but this may change during the plant's life or in future generations. Several processes are involved in the transfer:
- A powerful vector must be used, usually Agrobacterium tumefaciens, a bacterium that causes tumours in plants by inserting DNA from its own genetic code.
- A promoter is necessary to overcome a plant's natural resistance to infection. Usually the Cauliflower Mosaic Virus (CMV) is used, a virus that can cause damage to the pancreas, liver and brain of animals that ingest it. It 'turns on' the transferred gene (hyperexpression) but often 'turns on' other genes as well.
