Once released, the new living organisms made by genetic engineering are able to interact with other forms of life, reproduce, transfer their characteristics and mutate in response to environmental influences. In many cases they can never be recalled or contained. The probability that one or more of these releases could cause serious ecological harm increases all the time as more and more products are approved.
Genes engineered into plants and animals can be transferred to other species. For example, genes from GM crops, fish or trees may move into the gene pools of related species in the wild. The introduction of genetically engineered organisms into complex ecosystems may bring about effects that we are unable to control.
"I have the feeling that science has transgressed a barrier that should have remained inviolate . . . you cannot recall a new form of life . . . It will survive you and your children and your children’s children. An irreversible attack on the biosphere is something so unheard of, so unthinkable to previous generations, that I could only wish that mine had not been guilty of it." Erwin Chargaff, Professor Emeritus of Biochemistry, Columbia University, and discoverer of ‘Chargaff’s Rules’, which laid the scientific foundation for the discovery of the DNA double helix
Example: Researchers at Purdue University in the US used computer models and experimental research to study the potential effects of the release of a small number of GE fish into the wild. They estimated that just 60 genetically engineered fish, which were larger and more likely to mate, and yet which had less viable offspring, released into a wild population of 60 000 could lead to the extinction of the wild fish within 40 generations.