"Our results for the cotton from Egypt indicate that there has been the potential for more adaptive evolution going on in domesticated plant species than was appreciated up until now.
"Plants that are local to their particular area will develop genes which allow them to better tolerate the stresses they find in the environment around them.
"It's possible that cotton at the Qasr Ibrim site has adapted in response to extreme environmental stress, such as not enough water.
"This insight into how domesticated crops evolved when faced with environmental stress is of value for modern agriculture in the face of current challenges like climate change and water scarcity."
For archaeologists, the results also shed light on agricultural development in the ancient world.
There has long been uncertainty as to whether ancient Egyptians had imported domesticated cotton from the Indian subcontinent, as had happened with other crops, or whether they were growing a native African variety which had been domesticated locally.
The study's findings that the Qasr Ibrim seeds were of the G. herbaceum variety, native to Africa, rather than G. arboreum, which is native to the Indian subcontinent, represents the first molecular-based identification of archaeobotanical cotton to a species level.
Dr Allaby said the findings confirm there was an indigenous domestication of cotton in Africa which was separate from the domestication of cotton in India.
"The presence of cotton textiles on Egyptian and Nubian sites has been well documented but there has always been uncertainty among archaeologists as to the origin of these.
"It's not possible to identify some cotton varieties just by looking at them, so we were asked to delve into the DNA.
"We identified the African variety G. herbaceum, which suggest that domesticated cotton was not a cultural import it was a tec
|Contact: Anna Blackaby|
University of Warwick