The United States National Academies of Sciences, Engineering, and Medicine have established a committee to study the “economic, agronomic, health, safety, or other impacts of genetically engineered (GE) crops and food.” The committee’s results may be used to reassess the way GE crops, animals and foods are regulated in the U.S. and, hopefully, to improve that loophole-filled “regulatory” process. (For more information on the committee’s purpose and history, or for submitting comments, please see the committee’s website.)
Now, while this national review is taking place, is a good time to review the differences between genetic engineering and traditional breeding. The following lists serve to contrast the biological processes that underlie these technologies.
Traditional Breeding (i.e. its biological basis: sexual reproduction):
- Evolved over eons (along with “checkpoint” mechanisms to eliminate mistakes)
- Occurs between closely related organisms
- Genetic exchange occurs in reproductive cells,
- and occurs between related chromosomes,
- through homologous recombination
- Amount of DNA and spacing between genes remain the same
(Traditional) Genetic Engineering (particularly of crop plants):
- Is human-made, recently (and subject to human and other errors)
- Involves any gene from any organism (alive or dead) or synthesized in a lab
- Occurs in somatic cells
- Insertion into chromosomes occurs “randomly”
- Causes insertional mutation of recipient’s genes at rates of 27-63%
- Gene spacing and amount of genomic DNA are altered
- Involves “selectable marker” genes (e.g. kanamycin-resistance gene)
And because genetically engineered cells–in and of themselves–are of no use to agriculture, they must then be coaxed into becoming whole, fertile plants through another biological process called regeneration. And another form of mutation, called somaclonal variation, can occur during the regeneration process.
And, finally–to be of real use to agriculture–a genetically engineered, regenerated, fertile plant must be traditionally bred into a commercially viable crop variety.
To sum, there are multiple biologically relevant differences between the processes of traditional breeding and genetic engineering of crop plants; and the “process” of genetic engineering actually comprises multiple, different processes.
Therefore, genetic engineering is very different than traditional breeding. And, until proven otherwise, it should be assumed that the risks associated with these technologies must be different as well.
As a scientist trained in biology and genetics, I see no way other way to look at it.