Dr. Peter Shewry of the University of Bristol in the U.K. is one of the world’s most eminent agricultural scientists, an expert in wheat.
I came across this particularly telling comment from a review on genetic modification he coauthored with colleague, Nigel Halford:
Conventional breeding is limited by fertility barriers that allow only plants of the same, or closely related, species to be crossed. However, ‘wide crossing’ with more distantly related species can be achieved if ’embryo rescue’ is used to culture and regenerate embryos that would normally abort. Similarly, mutagenesis with chemical or physical mutagens can be used to induce new variation in the species of interest. Both wide crossing and mutation breeding can result in the expression in crop plants of many novel or modified genes, the effects of which cannot be assessed readily. However, both approaches are considered to be ‘conventional’, with no requirement for detailed assessment of the plants produced before they are introduced into the food chain.
In other words, it’s not just simply crossing plant A with plant B. It’s about rescuing mutated embryos that otherwise would not survive. It’s about inducing mutations in the genetic code that are impossible to control: Maybe it yields the trait you desire, such as short stature or photoperiod insensitivity, but it may yield multiple other effects, too, including unique proteins never before seen in nature.
And, as Drs. Halford and Shewry point out, these foods can be introduced into the food supply at your local supermarket “with no requirement for detailed assessment of the plants.” Nope: They’re just sold to you.
Repeat these sorts of efforts hundreds or thousands of times to generate the super-duper high-yield semi-dwarf strain of wheat and you’ve got oodles of opportunity to generate unanticipated effects on consuming humans.