Tannin is a type of phenolic compound – it's found in all plants and usually plays a role in preventing disease, resisting predation or encouraging seed dispersal by animals.

Researchers have tested ancient DNA from corn found at archaeological sites in Arkansas, shedding new light on the dispersal of one of the world’s most important food crops.

They are called Balanophora, and for over a century, the mechanism of their seed dispersal has remained a mystery.

"Our results reveal how a key dispersal trait -- bird wing shape -- can shape fundamental diversity patterns and island biogeography across scales," said Justin Baldwin, first author of the new study in Ecology Letters.

"Our results are strong evidence for tailored garment production using bone needles and fur-bearing animal pelts. These garments partially enabled modern human dispersal to northern latitudes and eventually enabled colonization of the Americas."