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Synchrotron light used to show human domestication of seeds from 2000 BC

19 July 2017

Synchrotron light used to show human domestication of seeds from 2000 BC

Dorian Fuller and Charlene Murphy have used the UK’s synchrotron facility, Diamond Light Source, to document for the first time the rate of evolution of seed coat thinning, a major marker of crop domestication, from archaeological remains.

Dorian and Charlene used the high-resolution X-ray computed tomography (HRXCT) technique, on Diamond’s I13-2 beamline, to measure for the first time the coat thickness throughout the entire seed of legume horsegram (Macrotyloma uniflorum), a bean commonly eaten in southern India between 2,000 BC and 1,200 BC, and have published their findings in the journal Scientific Reports.

As Dorian indicates:

  • Seed coat thickness is a great indicator of domestication, as thinner coats will mean faster germination of a seed when it is watered...But conventional methods of looking at the seed coat require breaking and destroying archaeological specimens.

According to Charlene:

  • Being able to look at the seed coat thickness without breaking the sample is possible by other methods, but you can only look at a spot on the seed...The beamline at Diamond has allowed us to look at the entire seed, and has shown considerable variation within individual specimen’s seed coat thickness.”
Synchrotron light used to show human domestication of seeds from 2000 BC

The results indicate that domestication of horsegram took place during the second millennium BC, with seed coats fixed in thickness by the early centuries AD. The findings also show the potential for HRXCT to be used to look at a variety of domesticated grains and pulses, such as peas.

Diamond Light Source is one of the most advanced scientific facilities in the world, and its pioneering capabilities are helping to keep the UK at the forefront of scientific research.

Dorian and Charlene are currently working on the ERC-funded ComPag project which aims to provide the first comparative synthesis for the domestication of plants and transition to agriculture at a global level.

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Update - Sept 2017