Scientists studying 1,600-year-old cotton from the banks of the Nile have found what they believe is the first evidence that punctuated evolution has occurred in a major crop group within the relatively short history of plant domestication.
The findings offer an insight into the dynamics of agriculture in the ancient world and could also help today's domestic crops face challenges such as climate change and water scarcity.
The researchers, led by Dr Robin Allaby from the School of Life Sciences at the University of Warwick, examined the remains of ancient cotton at Qasr Ibrim in Egypt's Upper Nile using high throughput sequencing technologies.
This is the first time such technology has been used on ancient plants and also the first time the technique has been applied to archaeological samples in such hot countries.
The site is located about 40 km from Abu Simbel and 70 km from the modern Sudanese border on the east bank of what is now Lake Nasser.
They also studied South American samples from sites in Peru and Brazil aged between 800 and nearly 4,000 years old.
The results showed that even over the relatively short timescale of a millennia and a half, the Egyptian cotton, identified as G. herbaceum, showed evidence of significant genomic reorganisation when the ancient and the modern variety were compared.
However closely-related G.Barbadense from the sites in South America showed genomic stability between the two samples, even though these were separated by more than 2,000 miles in distance and 3,000 years in time.
This divergent picture points towards punctuated evolution - long periods of evolutionary stability interspersed by bursts of rapid change having occurred in the cotton family.
Dr Allaby said: "We think of evolution as a very slow process, but as we analyse more genome information we can see that there's been a huge amount of large-scale proactive change during
|Contact: Anna Blackaby|
University of Warwick