ABSTRACT
Genetic engineering provides a very powerful and sophisticated means to create new combinations of genes and traits which, as far as we have been able to assess, mainly have developed separately and remained separate throughout their evolution. Separate development and the development and maintenance of barriers are prerequisites of the development of diversity — from species to ecosystem diversity. There are exceptions, especially in the microbial world. But even there, barriers have developed that normally restrict genetic exchange to a limited community of bacterial species. Unfortunately, we only have superficial understandings of those selective and regulating forces guiding horizontal transfer and, more importantly, of those factors helping new genes and traits to become established in new hosts. Further, engineered traits are not part of the existing cellular and organismal regulating mechanisms and feedback interactions. Recombinant genes are essentially inputs developed outside the “usual” organismal and environmental regulating interactions.
