21 research outputs found

    The efficacy of high-throughput sequencing and target enrichment on charred archaeobotanical remains

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    The majority of archaeological plant material is preserved in a charred state. Obtaining reliable ancient DNA data from these remains has presented challenges due to high rates of nucleotide damage, short DNA fragment lengths, low endogenous DNA content and the potential for modern contamination. It has been suggested that high-throughput sequencing (HTS) technologies coupled with DNA enrichment techniques may overcome some of these limitations. Here we report the findings of HTS and target enrichment on four important archaeological crops (barley, grape, maize and rice) performed in three different laboratories, presenting the largest HTS assessment of charred archaeobotanical specimens to date. Rigorous analysis of our data-excluding false-positives due to background contamination or incorrect index assignments-indicated a lack of endogenous DNA in nearly all samples, except for one lightly-charred maize cob. Even with target enrichment, this sample failed to yield adequate data required to address fundamental questions in archaeology and biology. We further reanalysed part of an existing dataset on charred plant material, and found all purported endogenous DNA sequences were likely to be spurious. We suggest these technologies are not suitable for use with charred archaeobotanicals and urge great caution when interpreting data obtained by HTS of these remains

    Searching for the origins of bere barley: a geometric morphometric approach to cereal landrace recognition in archaeology

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    Bere is a landrace of barley, adapted to the marginal conditions of northern Scotland, especially those of the Northern and Western Isles. The history of bere on these islands is long and, in an era of diminishing landrace cultivation, bere now represents one of the oldest cereal landraces in Europe still grown commercially. The longevity of bere raises the possibility of using grain characteristics of present-day specimens to identify bere in the archaeological record. Geometric modern morphometric (GMM) analysis of grains from bere and other barley landraces is conducted to determine whether landraces can be differentiated on grain morphology. Results indicate that there are morphological differences between bere and other British and Scandinavian landraces, and between bere from Orkney and the Western Isles, both of which are apparent in genetic analysis. This finding paves the way for the identification of bere archaeologically, helping to establish its status as living heritage and securing its commercial future. More broadly, this work indicates the potential of grain GMM for the recognition of cereal landraces, permitting the ancestry and exchange of landraces to be traced in the archaeological record
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