Archaeogenetic evidence of ancient Nubian barley evolution from six to two-row indicates local adaptation
Palmer, Sarah A., Moore, Jonathan D., Clapham, Alan J., Rose, Pamela and Allaby, Robin G.. (2009) Archaeogenetic evidence of ancient Nubian barley evolution from six to two-row indicates local adaptation. PLoS ONE , Vol.4 (No.7). e6301. ISSN 1932-6203
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Official URL: http://dx.doi.org/10.1371/journal.pone.0006301
Archaeobotanical samples of barley (Hordeum vulgare L.) found at Qasr Ibrim display a two-row phenotype that is unique to the region of archaeological sites upriver of the first cataract of the Nile, characterised by the development of distinctive lateral bracts. The phenotype occurs throughout all strata at Qasr Ibrim, which range in age from 3000 to a few hundred years.
Methodology and Findings
We extracted ancient DNA from barley samples from the entire range of occupancy of the site, and studied the Vrs1 gene responsible for row number in extant barley. Surprisingly, we found a discord between the genotype and phenotype in all samples; all the barley had a genotype consistent with the six-row condition. These results indicate a six-row ancestry for the Qasr Ibrim barley, followed by a reassertion of the two-row condition. Modelling demonstrates that this sequence of evolutionary events requires a strong selection pressure.
The two-row phenotype at Qasr Ibrim is caused by a different mechanism to that in extant barley. The strength of selection required for this mechanism to prevail indicates that the barley became locally adapted in the region in response to a local selection pressure. The consistency of the genotype/phenotype discord over time supports a scenario of adoption of this barley type by successive cultures, rather than the importation of new barley varieties associated with individual cultures.
|Item Type:||Journal Article|
|Subjects:||S Agriculture > SB Plant culture|
|Divisions:||Faculty of Science > Centre for Systems Biology
Faculty of Science > Life Sciences (2010- ) > Warwick HRI (2004-2010)
|Library of Congress Subject Headings (LCSH):||Barley -- Genetics, Plant genetics, Crops -- Evolution -- Nubia, Crops -- Adaptation -- Nubia|
|Journal or Publication Title:||PLoS ONE|
|Publisher:||Public Library of Science|
|Official Date:||22 January 2009|
|Access rights to Published version:||Open Access|
|Funder:||Natural Environment Research Council (Great Britain) (NERC)|
|Grant number:||NE/G005974/1 (NERC)|
# Blumler MA (1996) Harris DR, editor. London: UCL Press. pp. 25–50. In The Origins and Spread of Agriculture and Pastoralism in Eurasia,.
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