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Eurekalert.org

Map of China from Wikipedia

WASHINGTON UNIVERSITY IN ST. LOUIS—First domesticated 10,000 years ago in the Fertile Crescent of the Middle East, wheat and barley took vastly different routes to China, with barley switching from a winter to both a winter and summer crop during a thousand-year detour along the southern Tibetan Plateau, suggests new research from Washington University in St. Louis.
“The eastern dispersals of wheat and barley were distinct in both space and time,” said Xinyi Liu, assistant professor of archaeology in Arts & Sciences, and lead author of this study published in the journal PLOS One.
“Wheat was introduced to central China in the second or third millennium B.C., but barley did not arrive there until the first millennium B.C.,” Liu said. “While previous research suggests wheat cultivation moved east along the northern edge of the Tibetan Plateau, our study calls attention to the possibility of a southern route (via India and Tibet) for barley.”
Based on the radiocarbon analysis of 70 ancient barley grains recovered from archaeological sites in China, India, Kyrgyzstan and Pakistan, together with DNA and ancient textual evidence, the study tackles the mystery of why ancient Chinese farmers would change the seasonality of a barley crop that originated in a latitudinal range similar to their own.
The answer, Liu explains, is that barley changed from a winter to summer crop during its passage to China, a period in which it spent hundreds of years evolving traits that allowed it to thrive during short summer growing seasons in the highlands of Tibet and northern India.
“Barley arrives in central China later than wheat, bringing with it a degree of genetic diversity in relation to flowering time responses,” Liu said. “We infer such diversity reflects preadaptation of barley varieties along that possible southern route to seasonal challenges, particularly the high altitude effect, and that led to the origins of eastern spring barley.”
Liu’s research on the dispersal of wheat and barley cultivation adds a new chapter to our understanding of prehistoric food globalization, a process that began about 5000 B.C. and intensified around 1500 B.C. This ongoing research traces the geographic paths and dispersal times of crops and cultivation systems that expanded across Eurasia and eventually worldwide, from points of origination in North Africa and West, East and South Asia. The eastern expansion of wheat and barley is a key story in this process.
In the hot, arid southwest Asian region where wheat and barley were first domesticated, they were grown between autumn and subsequent spring to complete their life cycles before arrival of summer droughts. These early domesticated strains included genes carried over from wild grasses that triggered flowering and grain production as days grew longer with the approach of summer.
Because of this spring-flowering life cycle, early domesticated varieties of wheat and barley were poorly suited for cultivation in northern European climates with severe winters and a different day length pattern. Previous research by the second author in this study, Diane Lister, a postdoctoral research associate at the University of Cambridge, has shown that barley and wheat adapted to European climates by evolving a mutation that switched off the genes that made flowering sensitive to increases in day length, allowing them to be sown in spring and harvested in fall.
Liu’s study shows that barley evolved similar mutations on its way to China as farmers pushed its cultivation high into the mountains of the Tibetan Plateau. By the time barley reached central China, its genetic makeup had been altered so that flowering was no longer triggered by day length, allowing it to be planted in both spring and fall.
The ancient movement of wheat and barley cultivation into China offers two distinct stories about the adaption of newly introduced crops into an existing agrarian/culinary system, Liu said.
Ancient wheat that traveled to China along Silk Road routes also was genetically modified by farmers who selected strains that produced small-sized grains more suited to a Chinese cuisine that prepared them by boiling or steaming the whole grains. Larger wheat grains evolved in Europe where wheat was traditionally ground for flour.
Along the southern migration route for barley, the main story is the flowering time—changed by farmers to gain control over the seasonal pressures of high-altitude cultivation, Liu said.
Recovery of these ancient grains has become more routine in the last decade as scholars mastered a flotation technique that allows the separation of seeds and other minute biological material from excavated dirt immersed in a bucket of water. This approach, pioneered in China by the third author of this study, Zhijun Zhao, a professor of archaeology at the Chinese Academy of Social Sciences, has transformed the understanding of ancient farming in China.
The PLOS One findings reflect the contributions of 26 co-authors, including archaeologists who recovered the grains and those who analyzed them at leading archaeobotanical laboratories in the U.S., U.K., China and India. The team also includes leading experts for barley archaeogenetics, radiocarbon analysis and agricultural history around the globe.
“We’ve recently realized how much prehistoric crops moved around, on a scale much greater than anyone had envisaged,” said senior co-author Martin Jones, the George Pitt-Rivers Professor of Archaeological Science at Cambridge. “An intensive study of chronology, genetics and crop records now reveals how those movements laid the agrarian foundations of Bronze Age civilizations, enabling the control of seasons, and opening the way for rotation and multi-cropping.”

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Original article:

Eurekalert.org

 

University of Cincinnati archaeologist Alan Sullivan found scant evidence that people grew corn around the Grand Canyon 1,200 years ago. Instead, he said they used fire to cultivate wild foods.

Source: Archaeologist says fire, not corn, key to prehistoric survival in arid Southwest

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Eurekalert.org9-Nov-2017
New research shows that early farmers who migrated to Europe from the Near East spread quickly across the continent, where they lived side-by-side with existing local hunter-gatherers while slowly mixing with those groups over time
Max Planck Institute for the Science of Human History


Early Neolithic grave from Bátaszék (Hungary).
CREDIT
Anett Osztás

New research answers a long-debated question among anthropologists, archaeologists and geneticists: when farmers first arrived in Europe, how did they interact with existing hunter-gatherer groups? Prior studies have suggested these early Near Eastern farmers largely replaced the pre-existing European hunter-gatherers. Did the farmers wipe out the hunter-gatherers, through warfare or disease, shortly after arriving? Or did they slowly out-compete them over time? The current study, published today in Nature, suggests that these groups likely coexisted side-by-side for some time after the early farmers spread across Europe. The farming populations then slowly integrated local hunter-gatherers, showing more assimilation of the hunter-gatherers into the farming populations as time went on.
The Neolithic transition – the shift from a hunter-gatherer to a farming lifestyle that started nearly 10,000 years ago – has been a slowly unraveling mystery. Recent studies of ancient DNA have revealed that the spread of farming across Europe was not merely the result of a transfer of ideas, but that expanding farmers from the Near East brought this knowledge with them as they spread across the continent.
Numerous studies have shown that early farmers from all over Europe, such as the Iberian Peninsula, southern Scandinavia and central Europe, all shared a common origin in the Near East. This was initially an unexpected finding given the diversity of prehistoric cultures and the diverse environments in Europe. Interestingly, early farmers also show various amounts of hunter-gatherer ancestry, which had previously not been analyzed in detail.
The current study, from an international team including scientists from Harvard Medical School, the Hungarian Academy of Sciences and the Max Planck Institute for the Science of Human History, focused on the regional interactions between early farmers and late hunter-gatherer groups across a broad timespan in three locations in Europe: the Iberian Peninsula in the West, the Middle-Elbe-Saale region in north-central Europe, and the fertile lands of the Carpathian Basin (centered in what is now Hungary). The researchers used high-resolution genotyping methods to analyze the genomes of 180 early farmers, 130 of whom are newly reported in this study, from the period of 6000-2200 BC to explore the population dynamics during this period.
“We find that the hunter-gatherer admixture varied locally but more importantly differed widely between the three main regions,” says Mark Lipson, a researcher in the Department of Genetics at Harvard Medical School and co-first author of the paper. “This means that local hunter-gatherers were slowly but steadily integrated into early farming communities.”
While the percentage of hunter-gatherer heritage never reached very high levels, it did increase over time. This finding suggests the hunter-gatherers were not pushed out or exterminated by the farmers when the farmers first arrived. Rather, the two groups seem to have co-existed with increasing interactions over time. Further, the farmers from each location mixed only with hunter-gatherers from their own region, and not with hunter-gatherers, or farmers, from other areas, suggesting that once settled, they stayed put.
“One novelty of our study is that we can differentiate early European farmers by their specific local hunter-gatherer signature,” adds co-first author Anna Szécsényi-Nagy of the Hungarian Academy of Sciences. “Farmers from Spain share hunter-gatherer ancestry with a pre-agricultural individual from La Braña, Spain, whereas farmers from central Europe share more with hunter-gatherers near them, such as an individual from the Loschbour cave in Luxembourg. Similarly, farmers from the Carpathian Basin share more ancestry with local hunter-gatherers from their same region.”
The team also investigated the relative length of time elapsed since the integration events between the populations, using cutting-edge statistical techniques that focus on the breakdown of DNA blocks inherited from a single individual. The method allows scientists to estimate when the populations mixed. Specifically, the team looked at 90 individuals from the Carpathian Basin who lived close in time. The results – which indicate ongoing population transformation and mixture – allowed the team to build the first quantitative model of interactions between hunter-gatherer and farmer groups.
“We found that the most probable scenario is an initial, small-scale, admixture pulse between the two populations that was followed by continuous gene flow over many centuries,” says senior lead author David Reich, professor of Genetics at Harvard Medical School.
These results reflect the importance of building thorough, detailed databases of genetic information over time and space, and suggest that a similar approach should be equally revealing elsewhere in the world.

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Bicolor Sorghum

 

Original article:

Sci-news.com

 

Sorghum was domesticated from its wild ancestor more than 5,000 years ago, according to archaeological evidence uncovered by University College London archaeologist Dorian Fuller and colleagues in Sudan.

Sorghum (Sorghum bicolor) is a native African grass that was utilized for thousands of years by prehistoric peoples, and emerged as one of the world’s five most important cereal crops, along with rice, wheat, barley, and maize.

For a half century scientists have hypothesized that native African groups were domesticating sorghum outside the winter rainfall zone of the ancient Egyptian Nile Valley — where wheat and barley cereals were predominant — in the semi-arid tropics of Africa, but no archaeological evidence existed.

The newest evidence comes from an archaeological site near Kassala in eastern Sudan, dating from 3500 to 3000 BC, and is associated with the Butana Group culture.

“This new discovery in eastern Sudan reveals that during the 4th millennium BC, peoples of the Butana Group were intensively cultivating wild stands of sorghum until they began to change the plant genetically into domesticated morphotypes,” Dr. Fuller and co-authors said.

 

The researchers examined plant impressions within broken pottery from the largest Butana Group site, KG23.

“Ceramic sherds recovered from excavations undertaken by the Southern Methodist University Butana Project during the 1980s from the KG23 site were analyzed,” they explained.

“Examination of the plant impressions in the pottery revealed diagnostic chaff in which both domesticated and wild sorghum types were identified, thus providing archaeobotanical evidence for the beginnings of cultivation and emergence of domesticated characteristics within sorghum during the 4th millennium BC in eastern Sudan.”

“Along with the recent discovery of domesticated pearl millet in eastern Mali around 2500 BC, this discovery pushes back the process for domesticating summer rainfall cereals another thousand years in the Sahel, with sorghum, providing new evidence for the earliest known native African cultigen,” they said.

The research is published in the journal Current Anthropology.

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Original article:

Sciencenordic.com
By: Rasmus Kragh Jakobsen

A new study shows that the Mesopotamian farmers during a food crisis did not try to farm their land more intensively, but converted more land to arable land. (Photo: Shutterstock)

Ancient grain from the Middle East has given scientists an insight into how some of the world’s first cities developed.
Small, charred remains of grain that are at least 8,500 years old provide a fingerprint of ancient farming and how villages suddenly expanded over the course of a few hundred years into the large city states in ancient Mesopotamia—a historical area in present-day Syria and Iraq.
The grain can now reveal that as cities expanded and the need for food grew, so did the land dedicated to growing crops.
“It’s very exciting because until now the theory was that as the towns grew, they cultivated the land more intensively,” says archaeobotanist Mette Marie Hald from the National Museum of Denmark, who participated in the study.
“The study gives us an indirect indication of the political control of cities and how we imagine cities were established,” she says.
New knowledge on early city life
Arable farming made the cultivatable land valuable, and when land was inherited it could have laid the ground for a ruling elite of farmers and the beginnings of social inequality.
“It’s exciting and groundbreaking research, and the study strikes to the heart of many years of debate surrounding the economy and organisation of the early city societies,” says Tim Skuldbøl, archaeologist from the University of Copenhagen who also studies early urbanism but did not take part in the new study.
“Today, most people live in a city but don’t understand how they came about and why cities are organised the way they are. This archaeological research is important to understand the basic sociological building blocks that helped to form our urban societies today,” says Skuldbøl.
The study is published in the scientific journal, Nature Plants.
Villages shot up as settlement mounds
In the Khabur Valley in Northeast Syria, runs one of history’s most important rivers, the Euphrates. Together with the Tigris River, they define the region of Mesopotamia—which also means land between the rivers—where the world’s first civilisations emerged.
In the valley, archaeologists have found several ancient cities. One of them is Tell Brak, which was described by British archaeologist Sir Max Mallowan in the 1930s.
At first glance, Tell Brak looks like a small hill, but preserved under the surface are houses built upon houses.
“They have torn down houses and built on top of the old foundations, so the occupation level has risen over thousands of years. Now, it’s 40 to 60 metres high and like a small mountain,” says Hald.
Food for 30,000 inhabitants
Among the remains, archaeologists have discovered temples, large administrative buildings, and even long sewage pipes. But how the city grew to be so big, was still a mystery.
Eight thousand years ago, arable farming was just beginning with grain fields of wheat and barley. At this time, animals, such as cows, goats, and sheep, were domesticated.
At this time, people lived in villages of perhaps 100 to 200 people, and then suddenly, some 6,000 years ago, over a period of a few centuries, these villages grew to cities of more than 10,000 inhabitants.
The development of arable farming, which provided food for all these people, is a key piece of the puzzle to understand how these cities grew so quickly.
Atomic physics meets archaeology
In recent years, archaeologists have obtained a new peep-hole that allows them to see back in time. Amazingly enough, packets of information have survived 8,000 years in the form of grain from burned down houses.
“It’s a bit mean, but when a house burns down, we archaeologists are really happy because then grains are burnt and don’t rot. They can lie in the earth for thousands of years,” says Hald.
Most of us think of fire as a frightful, destructive power, but grain is strong enough to survive and save its secrets.

Every little grain records a piece of history of the conditions under which it was cultivated, in the form of stable isotopes of nitrogen and carbon.
Two routes to large towns
The scientists measured isotopes in 276 samples of grain discovered in Tell Brak and four other ancient cities in the northern region of Mesopotamia, dating to between 8,000 and 4,000 years ago: Tell Leilan, Tell Sabi Abyad, Tell Zeidan, and Hamoukar.
They compared the analysis with modern samples from test fields in France, Spain, Morocco, and Denmark, where old varieties of grain are grown under controlled conditions with manuring and irrigation.
Together with the knowledge of ancient climate, scientists can estimate very precisely how much or how little manure or irrigation was used. By comparing this with the archaeological layer which the samples came from, they could follow the development of agricultural practices through time.
The bigger the cities became, the less manure they used, which is surprising as further south in Iraq, they used widespread irrigation and farmed the land very intensively.
But now they know that practices to the north were very different, which means that there were at least two ways in which cities could expand.
Farmers made their own choices about their grain
The differences are probably closely related to the climate: Not enough rain in the dry south requiring irrigation versus the wetter northern region requiring less work-intensive input, where food output was boosted by converting more of the landscape to fields.
The grains also held clues of the socio-economic system of the time, revealing who held power in these early cities.
“It’s interesting that we find large pots filled with different crops in private homes, and from the isotope values we can see that they had very different manuring levels, so they must have come from different fields,” says Hald.
“It shows us that individual households had different fields around the town, where some were manured and others weren’t,” she says.
In other words, the grain suggests that there was no centralised arable economy, but that each farmer made their own choices.
Large farmers had power
If a king or nobleman controlled the fields, then all of the harvest would probably be collected centrally and then distributed. In this case, archaeologists might expect to see more consistent isotope values in the grain found in various households.
“Later, we see massive grain stores, where the crops must have come in from all the fields and stored in these large rooms, and distributed among the population,” says Hald.
“So what we see here is an indirect indication of how a town became controlled, and it doesn’t look like there was a strong centralised power at this time, and the society—at least agriculturally speaking—is still rather egalitarian,” she says.
In later deposits, the archaeologists found remains of temples, large storerooms, and administrative buildings, which suggests a central power had developed from the early agribusiness.
So it appears that the development began with a collective of important farmers.
“The extensive agriculture paved the way for some powerful families. You can say roughly that instead of a central royal power, in terms of economy, these cities may have been controlled by a team of large families,” says Hald.

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Local and international experts have begun archaeological work on what is reputed to be one of the earliest agriculture-based villages in the UAE

Source: Archaeologists shed light on life in the UAE 5,000 years ago

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Original article:

Nature.com

Changes to flowering times helped the staple crop spread into new areas thousands of years ago.

Genome sequences from nearly 2,000-year-old cobs of maize (corn) found in a Utah cave paint a portrait of the crop at the dawn of its adaptation to the highlands of the US southwest. That maize, researchers found, was small, bushy and — crucially — had developed the genetic traits it needed to survive the short growing seasons of high altitudes.

The team’s study1, published on 3 August in Science, is remarkable in how it tackles complex genetic traits governed by the interactions of many different genes, say researchers. It uses that information to create a detailed snapshot of a crop in the middle of domestication. Such insights could help modern plant breeders to buffer crops against global climate change.

Geneticists of both modern and ancient crops have poured tremendous effort into understanding maize, which was one of the most important subsistence crops in the New World thousands of years ago, and is a cornerstone of global agriculture today.

Maize originated in Mexico and rapidly spread into the lowlands of the southwest United States about 4,000 years ago. But communities at higher altitudes did not fully embrace the crop until 2,000 years later — a delay that has long puzzled archaeologists studying the region, says Kelly Swarts, a quantitative geneticist at the Max Planck Institute for Developmental Biology in Tübingen, Germany. “There was always the question: why wasn’t this catching on? Why weren’t people doing agriculture in the uplands?” she says.

Swarts and her colleagues turned to a site in a Utah cave called Turkey Pen Shelter, where a farming community lived about 2,000 years ago. Inhabitants of the cave raised turkeys, wove intricate baskets and shoes, and had the resources needed to store and process corn. Maize, which they probably served in soups and stews, comprised about 80% of their diet.

Complex crops

Swarts’s team sequenced the genomes of fifteen 1,900-year-old maize cobs found in the shelter and compared their sequences to those in a database of genomes and physical traits from some 2,600 modern maize lines. The researchers then used that information to extrapolate the physical characteristics of the Turkey Pen maize plants, including complex traits such as flowering time. The analysis revealed a crop that was shorter and more branched than modern varieties. “More like little bushes,” says Swarts, though the role of these traits is unclear. The crop also flowered more quickly than lowland varieties — an important adaptation to life in the highlands, which have a shorter growing season than lower elevations.

The analysis could open the way for similar studies of complex traits in other plants and animals, including humans, says Matthew Hufford, who studies evolutionary genomics in maize at Iowa State University in Ames. “We just now have the genetic tools and the analytic tools to make really good use of them.”

Plant evolutionary biologist Robin Allaby of the University of Warwick, UK looks forward to seeing the same approach applied to earlier stages of maize domestication. “That stuff was 1,900 years old, and a lot of the whistles and bangs had already happened,” he says. “It’s going to be really cool to see what a full 5,000-year-old maize phenotype looks like.”

A key finding from the study, says Hufford, was the realization that the genetic variants needed to adapt to highland life were already circulating in maize populations thousands of years ago “The diversity needed for high altitudes was there, but getting it in the right combination took 2,000 years,” he says.

And that diversity could be crucial for breeders as they try to adapt modern maize to a rapidly changing climate, says Swarts. “It’s really promising for maize’s future that it has so much standing variation — assuming we can conserve that diversity,” says Swarts. “If we needed to do this, it wouldn’t take 2,000 years. We could do it a lot faster now.”

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