Ancient gardeners saved the gourd

Humans’ green thumbs may have saved pumpkins, squashes and gourds from an Ice Age extinction, researchers report November 16 in Proceedings of the National Academy of Sciences. Genetic analysis of 91 ancient and modern gourds (Cucurbita sp.) suggests that humans began cultivating the plants nearly 10,000 years ago.

Wild gourds are very bitter, so the team tested 46 mammal genomes for a gene related to tasting bitterness. Smaller mammals had higher levels of the gene and probably rejected the bitter fruit, while megafauna like mastodons helped spread the seeds of early Cucurbita, the researchers think.

When the big animals died out, Cucurbita lost a seed-dispersing partner. Without humans to fill the role, some favorite fall fruits might not be around today.