The Taylor Lab recently carved pumpkins (Mia's are featured in the story thumbnail and one of Georgy's is feature here)听while learning about the domestication history of pumpkins from Peter (see below!). Happy Halloween everyone!
Cucurbita pepo听is the most widely cultivated and polymorphic of the squash species. Pumpkins, zucchini, cocozelle, and vegetable marrow are all varieties of听C. pepo听蝉耻产蝉辫.听pepo, while crookneck, straightneck, acorn, and scallop squash comprise a second clade,听C. pepo听蝉耻产蝉辫.听ovifera. The two subspecies were domesticated independently, starting around 10,000 years ago:听pepo听in the Oaxaca Valley of Mexico and听ovifera听in eastern North America. Before domestication, squashes were widespread across the Americas and formed a dispersal mutualism with large megafauna. Wild squash posess high amounts of bitter cucurbitacin toxins that deter most herbivores, but it is likely that mammoths and other large mammals were less sensitive to these compounds because they posessed few bitter taste receptor genes. Mass extinction of megafauna at the onset of the Holocene led to a dramatic decline in wild听Cucurbita. Today, wild ancestor populations of听ovifera听are rare across the southeastern US, while no wild form of subspecies听pepo听has been found.
Interestingly, turnips were originally part of听an Irish pagan festival and were used to ward off dark spirits before pumpkins eventually became the object of choice for carving and other Halloween decorations.
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Citations:
Chomicki, G., et al (2020). Origin and domestication of Cucurbitaceae crops: Insights from phylogenies, genomics and archaeology.听New Phytologist.
Kistler, L., et al (2015). Gourds and squashes (Cucurbita spp.) adapted to megafaunal extinction and ecological anachronism through domestication.听PNAS.
Paris, H. S., et al (2012). Parallel evolution under domestication and phenotypic differentiation of the cultivated subspecies of Cucurbita pepo (Cucurbitaceae).听Economic Botany.