Response to Kutchan: Genetic engineering, natural variation and substantial equivalence

[...]variation might, for example, reflect: (i) evolutionary differences between ecotypes associated with adaptation to the prevailing environmental conditions in geographically distinct regions and different habitats; (ii) differences in climatic conditions; (iii) differences in natural product content owing to plant responses to herbivore and pathogen attack; (iv) classical breeding to enhance a desired trait or to remove an unwanted property; (v) diurnal changes frozen-in by the time point at which the plant was harvested; or (vi) harvesting of the plant at different developmental stages [5,6].