Re-evaluating the history of the wheat domestication gene NAM-B1 using historical plant material

The development of agriculture is closely associated with the domestication of wheat, one of the earliest crop species. During domestication key genes underlying traits important to Neolithic agriculture were targeted by selection. One gene believed to be such a domestication gene is NAM-B1, affecting both nutritional quality and yield but with opposite effects. A null mutation, first arisen in emmer wheat, decreases the nutritional quality but delays maturity and increases grain size; previously the ancestral allele was believed lost during the domestication of durum and bread wheat by indirect selection for larger grain. By genotyping 63 historical seed samples originating from the 1862 International Exhibition in London, we found that the ancestral allele was present in two spelt wheat and two bread wheat cultivars widely cultivated at the time. This suggests that fixation of the mutated allele of NAM-B1 in bread wheat, if at all, occurred during modern crop improvement rather than during domestication. We also discuss the value of using archaeological and historical plant material to further the understanding of the development of agriculture.     

Subsistence and the isotopic signature of herding in the Bronze Age Hexi Corridor,NW Gansu,China

Dietary patterns at two Bronze Age sites in the Hexi Corridor are investigated by the analysis of stable carbon and nitrogen isotopes in faunal bone collagen. The findings are compared with archaeobotanical remains from one of the sites which include high proportions of millet (Panicum miliaceum and Setaria italica) as well as the western derived cereals wheat (Triticum aestivum), barley (Hordeum vulgare) and oat (Avena sativa). The isotopic data indicate domestic omnivores (Canis and Sus) had diets dominated by millet. Minimally offset δ¹⁵N values between herbivore and omnivore fauna suggest low consumption of animal protein by omnivores. Diets of herded animal (Bos and Caprinae) included only low proportions of C4 foods, suggesting that these animals were not regularly foddered with millet plants, and that their grazing areas were mostly beyond the agricultural zone. The wide range in δ¹⁵N values amongst herbivore fauna (4.1‰–11.8‰) suggests grazing occurred in a variety of ecological zones, and this would be consistent with the occurrence of long-distance transport of livestock in the region.     

Next generation sequencing of DNA in 3300-year-old charred cereal grains

We investigated whether ‘next generation’ methods can be used to sequence ancient DNA molecules in charred cereal grains. We prepared a DNA extract from a mixed sample of barley, einkorn, emmer and broomcorn millet, taken from a 3300-year-old assemblage of charred cereal grains from Assiros Toumba, Greece. Using the SOLiD 5500 system, we obtained 21,112,844 unique sequence reads. Of these, 178,779 had a 75% or greater nucleotide sequence similarity with one or more entries in the full nucleotide sequence database; 496 of these matches were to previously reported sequences from barley, einkorn, emmer, broomcorn millet or related species such as hexaploid wheat. The unique reads were also compared with a database comprising only wheat sequences. This analysis identified 1658 charred grain sequences that had 90% or greater similarity with segments of the wheat genome. The presence of barley, wheat and millet sequences in the next generation dataset confirms the presence of ancient DNA in this charred grain assemblage. Enrichment of extracts by hybridization capture or equivalent methods is likely to enable sequences to be obtained for entire genes and other genomic regions of interest.     

Variations in the C/C ratios of modern wheat grain, and implications for interpreting data from Bronze Age Assiros Toumba, Greece

Variations in the ¹³C/¹²C ratios of wheat grain at different spatial and temporal scales are examined by analysis of modern samples, including harvests of einkorn and durum wheat from Greece, and serve as a guide to interpreting data for Bronze Age grains from Assiros Toumba. The normal distribution and low variability of δ¹³C values of einkorn from 24 containers in the Assiros storerooms are consistent with pooling of local harvests, but less likely to represent the harvest of several years or include grain imported from further afield. Correlation between emmer and spelt δ¹³C values provides strong support for other evidence that these were grown together as a maslin crop. ¹³C discrimination (Δ) for the Bronze Age samples is estimated to be 2.5‰ larger than at present, and would be consistent with an intensive, horticultural regime of cereal cultivation, possibly involving some watering.     

Ancient DNA in archaeological wheat grains: preservation conditions and the study of pre-Hispanic agriculture on the island of Gran Canaria (Spain)

The recovery of ancient DNA from archaeological wheat samples under different preservation conditions was assessed using a number of genetic markers. It was possible to amplify nuclear DNA from desiccated grains but not from charred. The desiccated grain was from a pre-Hispanic grain silo in Gran Canaria and showed excellent DNA preservation, enabling the amplification of the ribosomal DNA markers IGS and ITS, the upstream region of the HMW-glutenin locus and single-locus nuclear microsatellites. Our results demonstrated the presence of both durum and bread wheat in an assemblage of naked grain. We were also able to identify different genotypes in durum wheat and compare these with extant landraces, providing insights into the agrarian practices of the ancient Canarians and the origin of their crops.     

Wheat in ancient Korea: a size comparison of carbonized kernels

Archaeobotanical research over the past decades has revealed that bread wheat of a compact form, called “Ezo wheat” in Japan, was present in the Far East Asian region (Primorye in the Russian Far East, the Korean peninsula, and the Japanese archipelago) during the early stage of wheat cultivation. In response to the previous observations, carbonized wheat grains from the sites in the southern part of the Korean peninsula were measured and their sizes were compared across these sites and with other sites in East Asia. The examination indicates that grains dated over the period of AD 100–600 were considerably smaller than the modern specimens but were plumper than the previously reported Ezo wheat. The new data sets suggest that wheat with plumper kernels was introduced to the region no later than the Three-Kingdoms period (ca. AD 300–668) and continued to be cultivated until the Joseon period (1392–1910).     

汉代黄河流域麦作发展的环境因素与技术影响

汉代冬小麦的推广与普及,具有自东向西的时空特点。麦作发展是区域自然环境与技术条件交互作用的结果,其中自然环境条件是影响汉代黄河流域冬麦普及过程的基本因素。不论是黄河下游地区冬麦种植的较早普及还是关中地区冬麦推广的迟滞,均首先与当地的自然环境有关。在黄河下游地区,人们利用冬麦的生长特性趋利避害,减少和防止河汛水患的影响,保障粮食生产,麦子得以广泛种植。在关中地区,干旱的困扰一度制约了冬麦的推广和普及。在自然因素推动下的汉代麦作推广与普及,促进了黄河流域抗旱耕作及粮食加工技术的发展,影响深远。     

Ancient DNA analysis of desiccated wheat grains excavated from a Bronze Age cemetery in Xinjiang

Wheat has been one of the most important crop in Eurasia since the Neolithic period. Understanding the spread of wheat cultivation is crucial to understanding the spread of agriculture as a whole and the interactions between prehistoric populations across the Eurasian continent. However, the routes by which wheat cultivation spread eastwards have been poorly understood to date, due to the scarcity of plant remains recovered from archaeological sites. Desiccated wheat grains excavated from the Xiaohe cemetery in Xinjiang, and dated to the early Bronze Age, show excellent DNA preservation. Here we present an ancient DNA (aDNA) analysis of wheat (Triticum sp.) grains excavated from Xiaohe and provide the first definitive evidence for bread wheat in China during the Bronze Age. The nuclear ribosomal DNA internal transcribed spacer regions (ITS1 and ITS2) and the intergenic spacer region (IGS) were amplified. The IGS region within the D genome of wheat has a 71 bp insertion that is absent from corresponding regions in the A and B genomes. The results showed that the Xiaohe wheat showed most sequence similarity to hexaploid bread wheat (Triticum aestivum), including the characteristic insertion into the D genome. The presence of bread wheat at the Xiaohe cemetery is discussed in relation to it having spread into Xinjiang by the Bronze Age, providing new insight into the origins of bread wheat in East Asia.     

Some food offerings from Ur,excavated by sir leonard woolley,and previously unpublished

As a result of excavations at Ur by Woolley (1923–1934) food debris was recovered and is now reported on. Plant remains include chickpea, six-row barley, wheat, pea, dates, perforated crab apple rings and possible flat bread. Of special interest are the chickpeas which are among the earliest found in lowland Mesopotamia and the crab apple rings which have not been found before in ancient deposits in the Near East. Of the mammals, caprovids seem to have been most important as food offerings. The occurrence of tunny fish vertebrae was unexpected.The preliminary analysis of some inorganic residues is so far inconclusive although it is possible that one of the residues may originally have contained salt.