Genetics Study Narrows Upland Cotton Domestication to Yucatan 7,000–4,000 Years Ago, Revising Earlier Peruvian Hypothesis

Upland cotton was domesticated between 7,000 and 4,000 years ago in the Yucatan peninsula, according to a genetics-driven study published in the Proceedings of the National Academy of Sciences by Weixuan Ning, Jonathan Wendel at Iowa State University, Corrinne Grover and colleagues.

, Mexico, Puerto Rico and Guadeloupe. Genetic diversity proved highest in the northwestern Yucatán, the location the researchers identified as the crop's point of origin.

Early domestic Upland cotton then spread through Central America, the Caribbean and northern South America, where new variants emerged. Spanish conquistadores later carried the Mexican domesticate to Europe in the 16th century. The earliest cotton fabrics recovered so far come from Neolithic Peru and date to about 8,000 years ago.

Until the new genetic evidence, many researchers had assumed domestication began there. Upland cotton is now the most profitable non-food crop in the world and accounts for the bulk of global production. It is grown on every continent that can support it and is valued for its adaptability to varied soils and its relatively high yields.

Egyptian cotton, a separate species domesticated in Peru or Ecuador at roughly the same time, supplies about 5 percent of world output and is prized for longer, softer fibers. Levant cotton and Tree cotton together provide another 5 percent. The last common ancestor of all cotton species emerged in Africa between 10 million and 5 million years ago.

Its seeds dispersed across land and sea, giving rise to more than 50 species worldwide, of which only four are cultivated at scale. Tree cotton originated in the Indian subcontinent or Sri Lanka and may have been domesticated as early as 7,000 years ago; it was later grown by the Indus Valley civilization.

Egyptian cotton is also cultivated in parts of the United States under the name American Pima.

The fibers of cotton are elongated single-celled seed hairs. "The fibers … are among the most exaggerated and remarkable cells in plants," Wendel told Reuters. More than 60 percent of clothing today is made from synthetic fibers such as polyester, nylon and acrylic, which can be produced for $1 to $2 per meter.

Cotton begins at roughly $8 per meter, contributing to the rise of polycotton blends and increasing volumes of non-biodegradable textile waste. The earliest known prehistoric sewing dates to 12,400 years ago and was found among paleo-American remains in Oregon.

Indirect evidence, including ancient needles and cord made from flax, indicates that humans and Neanderthals produced textiles at least 34,000 years ago, with the oldest surviving examples recovered from caves in Georgia.