What is the implicit regulatory assumption streamlining approval for incremental GM changes?

Substantial equivalence to the traditional counterpart.

The concept of substantial equivalence forms a cornerstone in the regulatory review process for genetically modified (GM) foods, especially those involving incremental changes, such as adding pest resistance to an existing crop line. This framework assumes that if the new GM food is chemically and nutritionally equivalent to its non-GM predecessor, apart from the specific, intended beneficial trait introduced, it should be considered equally safe. This approach allows regulators to focus intensive scrutiny on the newly introduced component, such as a novel protein, rather than requiring the developer to conduct extensive retesting of the entire plant's biology from scratch, thus streamlining the approval process for targeted modifications.