Massive morphological changes occurred during the domestication of maize from wild teosinte. Some of the most important shifts are due to altered expression patterns of major regulatory genes.
Kane, N. C., & Rieseberg, L. H. (2005, February 22). Maize genetics: The treasure of the Sierra Madre. Current Biology. Cell Press. https://doi.org/10.1016/j.cub.2005.02.014