5,200-year-old grains in the eastern Altai Mountains redate trans-Eurasian crop exchange

5,200-year-old grains in the eastern Altai Mountains redate trans-Eurasian crop exchange

Agricultural crops dispersed across Eurasia more than five millennia ago, causing significant cultural change in human populations across the ancient world. New discoveries in the Altai Mountains illustrate that this process occurred earlier than believed

trans-Eurasian crop exchange
Dr. Xinying Zhou and his team from the IVPP in Beijing excavated the Tangtian Cave site during the summer of 2016. Credits: Xinying Zhou

Most people are familiar with the historical Silk Road, but fewer people realize that the exchange of items, ideas, technology, and human genes through the mountain valleys of Central Asia started almost three millennia before organized trade networks formed. These pre-Silk Road exchange routes played an important role in shaping human cultural developments across Europe and Asia, and facilitated the dispersal of technologies such as horse breeding and metal smelting into East Asia. One of the most impactful effects of this process of ancient cultural dispersal was the westward spread of northeast Asian crops and the eastward spread of southwest Asian crops. However, until the past few years, a lack of archaeobotanical studies in Central Asia left a dearth of data relating to when and how this process occurred.

This new study, led by scientists from the Chinese Academy of Sciences and the Max Planck Institute for the Science of Human History, provides details of recently recovered ancient grains from the far northern regions of Inner Asia. Radiocarbon dating shows that the grains include the oldest examples of wheat and barley ever recovered this far north in Asia, pushing back the dates for early farming in the region by at least a millenium. These are also the earliest domesticated plants reported from the northern half of Central Asia, the core of the ancient exchange corridor. This study pulls together sedimentary pollen and ancient wood charcoal data with archaeobotanical remains from the Tiangtian archaeological site in the Chinese Altai Mountains to reveal how humans cultivated crops at such northern latitudes. This study illustrates how adaptable ancient crop plants were to new ecological constraints and how human cultural practices allowed people to survive in unpredictable environments.

The Northern Dispersal of Cereal Grains

The ancient relatives of wheat and barley plants evolved to grow in the warm and dry climate of the eastern Mediterranean and southwest Asia. However, this study illustrates that ancient peoples were cultivating these grasses over five and a half thousand kilometers to the northeast of where they originally evolved to grow. In this study, Dr. Xinying Zhou and his colleagues integrate paleoenvironmental proxies to determine how extreme the ecology was around the archaeological cave site of Tangtian more than five millennia ago, at the time of its occupation. The site is located high in the Altai Mountains on a cold, dry landscape today; however, the study shows that the ecological setting around the site was slightly warmer and more humid at the time when people lived in and around this cave.

The slightly warmer regional conditions were likely the result of shifting air masses bringing warmer, wetter air from the south. In addition to early farmers using a specific regional climate pocket to grow crops in North Asia, analysis showed that the crops they grew evolved to survive in such northern regions. The results of this study provide scholars with evidence for when certain evolutionary changes in these grasses occurred, including changes in the programed reliance of day length, which signals to the plant when to flower, and a greater resistance to cold climates.

trans-Eurasian crop exchange
Charred seeds from Tontian Cave site. Credits: Xinying Zhou

The Trans-Eurasian Exchange and Crop Dispersal

The ancient dispersal of crops across Inner Asia has received a lot of attention from biologists and archaeologists in recent years; as Dr. Spengler, one of the study's lead authors, discusses in his recent book Fruit from the Sands, these ancient exchange routes shaped the course of human history. The mingling of crops originating from opposite ends of Asia resulted in the crop-rotation cycles that fueled demographic growth and led to imperial formation. East Asian millets would become one of the most important crops in ancient Europe and wheat would become one of the most important crops in East Asia by the Han Dynasty. While the long tradition of rice cultivation in East Asia made rice a staple of the Asian kitchen, Chinese cuisine would be unrecognizable without wheat-based food items like steamed buns, dumplings, and noodles. The discovery that these plants dispersed across Eurasia earlier than previously understood will have lasting impacts on the study of cultivation and labor practices in ancient Eurasia, as well as the history cultural contact and shifts in culinary systems throughout time.

These new discoveries provide reason to question these views, and seem to suggest that mixed small-scale human populations made major contributions to world history through migration and cultural and technological exchange. "This study not only presents the earliest dates for domesticated grains in far North Asia," says Professor Xiaoqiang Li, director of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, "it represents the earliest beginning of a trans-Eurasian exchange that would eventually develop into the great Silk Road".

Dr. Xinying Zhou, who headed the study and directs a research team at the IVPP in Beijing, emphasizes that "this discovery is a testament to human ingenuity and the amazing coevolutionary bond between people and the plants that they maintain in their cultivated fields."

photo of the stone men (????? Chimulchek Culture) in the steppe area of Altai Mountains. These figures are characteristic of the peoples who live in the area around the time of occupation at Tongtian. These specific examples are located at the Chimulchek site (ca. 4000 years old) and not far from Tongtian Cave. Ceramic sherds from the cave suggest that the occupants in the cave shared similar cultural traits to other people in the region. Credits: Jianjun Yu

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Title: 5200-year-old cereal grains from the eastern Altai Mountains predate the trans-Eurasian crop exchange
Authors: Xinying Zhou, Jianjun Yu, Robert Nicolas Spengler, Hui Shen, Keliang Zhao, Junyi Ge, Yige Bao, Junchi Liu, Qingjiang Yang, Guanhan Chen, Peter Weiming Jia, and Xiaoqiang Li
Publication: Nature Plants
DOI: https://doi.org/10.1038/s41477-019-0581-y

 

The press release about the trans-Eurasian crop exchange is from Max Planck Institute for the Science of Human History / DE


Archaeologists find Bronze Age tombs lined with gold near the Griffin Warrior

Archaeologists find Bronze Age tombs lined with gold

The family tombs are near the 2015 site of the 'Griffin Warrior,' a military leader buried with armor, weapons and jewelry.

A gold ring depicts bulls and barley, the first known representation of domesticated animals and agriculture in ancient Greece. Credits: UC Classics

Archaeologists with the University of Cincinnati have discovered two Bronze Age tombs containing a trove of engraved jewelry and artifacts that promise to unlock secrets about life in ancient Greece.

The UC archaeologists announced the discovery Tuesday in Greece.

Jack Davis and Sharon Stocker, archaeologists in UC's classics department, found the two beehive-shaped tombs in Pylos, Greece, last year while investigating the area around the grave of an individual they have called the "Griffin Warrior," a Greek man whose final resting place they discovered nearby in 2015.

Like the Griffin Warrior's tomb, the princely tombs overlooking the Mediterranean Sea also contained a wealth of cultural artifacts and delicate jewelry that could help historians fill in gaps in our knowledge of early Greek civilization.

UC's team spent more than 18 months excavating and documenting the find. The tombs were littered with flakes of gold leaf that once papered the walls.

"Like with the Griffin Warrior grave, by the end of the first week we knew we had something that was really important," said Stocker, who supervised the excavation.

"It soon became clear to us that lightning had struck again," said Davis, head of UC's classics department.

Bronze Age Tombs Griffin Warrior Pylos
UC archaeologists discovered two large family tombs at Pylos, Greece, strewn with flakes of gold that once lined their walls. The excavation took more than 18 months. Credits: UC Classics

The Griffin Warrior is named for the mythological creature -- part eagle, part lion -- engraved on an ivory plaque in his tomb, which also contained armor, weaponry and gold jewelry. Among the priceless objects of art was an agate sealstone depicting mortal combat with such fine detail that Archaeology magazine hailed it as a "Bronze Age masterpiece."

Artifacts found in the princely tombs tell similar stories about life along the Mediterranean 3,500 years ago, Davis said. A gold ring depicted two bulls flanked by sheaves of grain, identified as barley by a paleobotanist who consulted on the project.

"It's an interesting scene of animal husbandry -- cattle mixed with grain production. It's the foundation of agriculture," Davis said. "As far as we know, it's the only representation of grain in the art of Crete or Minoan civilization."

UC archaeologists found a sealstone made from semiprecious carnelian in the family tombs at Pylos, Greece. The sealstone was engraved with two lionlike mythological figures called genii carrying serving vessels and incense burners facing each other over an altar and below a 16-pointed star. The other image is a putty cast of the sealstone. Credits: UC Classics

Like the grave of the Griffin Warrior, the two family tombs contained artwork emblazoned with mythological creatures. An agate sealstone featured two lion-like creatures called genii standing upright on clawed feet. They carry a serving vase and an incense burner, a tribute for the altar before them featuring a sprouting sapling between horns of consecration, Stocker said.

Above the genii is a 16-pointed star. The same 16-pointed star also appears on a bronze and gold artifact in the grave, she said.

"It's rare. There aren't many 16-pointed stars in Mycenaean iconography. The fact that we have two objects with 16 points in two different media (agate and gold) is noteworthy," Stocker said.

The genius motif appears elsewhere in the East during this period, she said.

"One problem is we don't have any writing from the Minoan or Mycenaean time that talks of their religion or explains the importance of their symbols," Stocker said.

UC's team also found a gold pendant featuring the likeness of the Egyptian goddess Hathor.

"Its discovery is particularly interesting in light of the role she played in Egypt as protectress of the dead," Davis said.

The identity of the Griffin Warrior is a matter for speculation. Stocker said the combination of armor, weapons and jewelry found in his tomb strongly indicate he had military and religious authority, likely as the king known in later Mycenaean times as a wanax.

Likewise, the princely tombs paint a picture of accumulated wealth and status, she said. They contained amber from the Baltic, amethyst from Egypt, imported carnelian and lots of gold. The tombs sit on a scenic vista overlooking the Mediterranean Sea on the spot where the Palace of Nestor would later rise and fall to ruins.

"I think these are probably people who were very sophisticated for their time," she said. "They have come out of a place in history where there were few luxury items and imported goods. And all of a sudden at the time of the first tholos tombs, luxury items appear in Greece.

"You have this explosion of wealth. People are vying for power," she said. "It's the formative years that will give rise to the Classic Age of Greece."

The antiquities provide evidence that coastal Pylos was once an important destination for commerce and trade.

"If you look at a map, Pylos is a remote area now. You have to cross mountains to get here. Until recently, it hasn't even been on the tourist path," Stocker said. "But if you're coming by sea, the location makes more sense. It's on the way to Italy. What we're learning is that it's a much more central and important place on the Bronze Age trade route."

The princely tombs sit close to the palace of Nestor, a ruler mentioned in Homer's famous works "The Iliad" and "The Odyssey." The palace was discovered in 1939 by the late UC Classics professor Carl Blegen. Blegen had wanted to excavate in the 1950s in the field where Davis and Stocker found the new tombs but could not get permission from the property owner to expand his investigation. The tombs would have to wait years for another UC team to make the startling discovery hidden beneath its grape vines.

Excavating the site was particularly arduous. With the excavation season looming, delays in procuring the site forced researchers to postpone plans to study the site first with ground-penetrating radar. Instead, Stocker and Davis relied on their experience and intuition to focus on one disturbed area.

"There were noticeable concentrations of rocks on the surface once we got rid of the vegetation," she said.

Those turned out to be the exposed covers of deep tombs, one plunging nearly 15 feet. The tombs were protected from the elements and potential thieves by an estimated 40,000 stones the size of watermelons.

The boulders had sat undisturbed for millennia where they had fallen when the domes of the tombs collapsed. And now 3,500 years later, UC's team had to remove each stone individually.

"It was like going back to the Mycenaean Period. They had placed them by hand in the walls of the tombs and we were taking them out by hand," Stocker said. "It was a lot of work."

At every step of the excavation, the researchers used photogrammetry and digital mapping to document the location and orientation of objects in the tomb. This is especially valuable because of the great number of artifacts that were recovered, Davis said.

"We can see all levels as we excavated them and relate them one to the other in three dimensions," he said. UC's team will continue working at Pylos for at least the next two years while they and other researchers around the world unravel mysteries contained in the artifacts.

"It has been 50 years since any substantial tombs of this sort have been found at any Bronze Age palatial site. That makes this extraordinary," Davis said.

 

Press release from the University of Cincinnati, by Michael Miller.


Drinking, feasting and dietary habits of Early Celts in Burgundy

Archaeology -- what the Celts drank

drinking Celts
Greek drinking cup from the Early Celtic princely burial mound Kleinaspergle. This vessel is similar to those whose pottery fragments were found in the Celtic settlement on the Mont Lassois. Credit: Württemberg State Museum, P. Frankenstein / H. Zwietasch.

Research carried out by an international team led by scientists from Ludwig-Maximilians-Universitaet (LMU) in Munich and the University of Tübingen reveals aspects of the drinking and dietary habits of the Celts, who lived in Central Europe in the first millennium BCE.

The authors of the new study analyzed 99 ceramic drinking vessels, storage and transport jars recovered during excavations at Mont Lassois in Burgundy. This was the site of a fortified 'princely' settlement of the Early Celts. The finds included pottery and bronze vessels that had been imported from Greece around 500 BCE. "This was a period of rapid change, during which vessels made in Greece and Italy reached the region north of the Alps in large numbers for the first time. It has generally been assumed that this indicates that the Celts began to imitate the Mediterranean lifestyle, and that only the elite were in a position to drink Mediterranean wine during their banquets," says LMU archaeologist Philipp Stockhammer, who led the project. "Our analyses confirm that they indeed consumed imported wines, but they also drank local beer from the Greek drinking bowls. In other words, the Celts did not simply adopt foreign traditions in their original form. Instead, they used the imported vessels and products in their own ways and for their own purposes. Moreover, the consumption of imported wine was apparently not confined to the upper echelons of society. Craftsmen too had access to wine, and the evidence suggests that they possibly used it for cooking, while the elites quaffed it in the course of their drinking parties. The study shows that intercultural contact is a dynamic process and demonstrates how easy it is for unfamiliar vessels to serve new functions and acquire new meanings."

At the University of Tübingen, Maxime Rageot analyses organic residues found in pottery from Mont Lassois. Credit: Victor S. Brigola

Chemical analysis of the food residues absorbed into the ancient pots now makes it possible to determine what people ate and drank thousands of years ago. The group of authors based at the University of Tübingen analyzed these chemical fingerprints in the material from Mont Lassois. "We identified characteristic components of olive oil and milk, imported wine and local alcoholic beverages, as well as traces of millet and beeswax," says Maxime Rageot, who performed the chemical analyses in Tübingen. "These findings show that - in addition to wine - beers brewed from millet and barley were consumed on festive or ritual occasions." His colleague Cynthianne Spiteri adds: "We are delighted to have definitively solved the old problem of whether or not the early Celts north of the Alps adopted Mediterranean drinking customs. - They did indeed, but they did so in a creative fashion!"

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The results of the study, which forms part of the BEFIM project (Meanings and Functions of Mediterranean Imports in Early Iron Age Central Europe), have just been published in the online journal PLOS ONE. The collaborative investigation was carried out by researchers from LMU Munich, the University of Tübingen, the Württemberg State Museum, the Landesamt für Denkmalpflege beim Regierungspräsidium Stuttgart, the University of Zürich and the University of Burgundy.

 

Press release from the Ludwig-Maximilians-Universität München

 

Early Celts in Burgundy appropriated Mediterranean products and feasting practices

Organic residue analysis of imported Mediterranean pottery fragments detects imported olive oil and wine as well as local beers

Selection of the Early Celtic vessels held in the archive of the Württemberg State Museum. Credit: Victor S. Brigola, CC-BY

Early Celts in eastern France imported Mediterranean pottery, as well as olive oil and wine, and may have appropriated Mediterranean feasting practices, according to a study published June 19, 2019 in PLOS ONE, by Maxime Rageot from Ludwig-Maximilians-Universität München and the University of Tübingen, and colleagues.

Hundreds of fragments of imported Mediterranean pottery have been excavated from the Early Celtic hillfort site of Vix-Mont Lassois in Burgundy, France. This study is the first to investigate the impact of these Mediterranean imports and of Mediterranean feasting/consumption practices on Early Celtic culture (7th - 5th century BC), using molecular organic residue analysis techniques. The authors performed gas chromatography and GC-mass spectrometry analyses on organic residues extracted from 99 ceramic fragments found at Vix-Mont Lassois: some from 16 vessels imported from the Mediterranean and some from locally produced vessels from different contexts (elite, artisan, ritual, and military).

The results showed that the imported vessels were not only used for wine drinking as an appropriation of Mediterranean feasting practices, but also to drink local beers spiced with pine resins, in what appears to be an intercultural adaptation. Additional home-grown beverages were also found in local pottery, including what may have been millet-based beer, probably consumed only by low-status individuals, and barley-based beer and birch-derived beverages, which seemed to be consumed by high-status individuals. Local pine resins and plant oils were also identified. Beeswax was present in around 50% of the local pottery vessels, possibly indicating that mead was a popular fermented beverage or that the Early Celts liked to sweeten their beverages with honey.

The authors note that common foods such as wheat, barley and rye might have been present in the vessels but could not be detected by their analysis centuries later. Despite this limitation, this study sheds new light on the role of imported Mediterranean food and drink in helping shape Early Celtic feasting practices and demonstrates the potential of this type of molecular analysis also for other archaeological sites.

The authors add: "The Celts in the Early Iron Age did not just drink imported Greek wine from their imported Greek pottery. They also used the foreign vessels in their own way for drinking different kinds of local beer, as organic residue analysis of ca. 100 Early Iron Age local and Mediterranean drinking vessels from Mont Lassois (France) shows."

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Citation: Rageot M, Mötsch A, Schorer B, Bardel D, Winkler A, Sacchetti F, et al. (2019) New insights into Early Celtic consumption practices: Organic residue analyses of local and imported pottery from Vix-Mont Lassois. PLoS ONE 14(6): e0218001. https://doi.org/10.1371/journal.pone.0218001

Funding: MR research was funded by the Deutsches Bundesministerium für Bildung und Forschung (Federal Minstry of Education and Research). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

 

Press release from the Public Library of Science


Dramatic change in ancient nomad diets coincides with expansion of networks across Eurasia

Dramatic change in ancient nomad diets coincides with expansion of networks across Eurasia

nomad pastoralists diets
Map of millet and wheat/barley consumption over time: a) 1000-500 cal BC, b) 500-200 cal BC, and c) 200 BC-AD 400. Credit: Map of millet and wheat/barley consumption over time: a) 1000-500 cal BC, b) 500-200 cal BC, and c) 200 BC-AD 400

A meta-analysis of dietary information recorded in the bones of ancient animals and humans recovered from sites scattered across the Eurasian steppe, from the Caucasus region to Mongolia, demonstrates that pastoralists spread domesticated crops across the steppe through their trade and social networks. Researchers from Kiel University sifted through previously published stable isotopic data and applied new quantitative analyses that calibrate human dietary intake against environmental inputs. The results have allowed them to better isolate the timing of the incorporation of agricultural products into the diets of pastoral nomads and, crucially, link burgeoning socio-political networks to this dietary transformation.

Through a big data project that explored over a thousand stable isotope data points, researchers were able to find evidence for an early transition to agriculture - based on dietary intake across Eurasia. "Our understanding of the pace of crop transmission across the Eurasian steppe has been surprisingly unclear due in part to a focus on the excavation of cemeteries, rather than settlements where people threw out their food," says Alicia Ventresca Miller, lead author, formerly of Kiel University and currently at the Max Planck Institute for the Science of Human History. "Even when settlement sites are excavated, the preservation of carbonized seed remains is often poor. This is what makes stable isotope analyses of human remains from this region so valuable - it provides direct insights into the dietary dynamics of ancient pastoralists who inhabited diverse environments."

Millet spreads across the Eurasian steppe

Millet, originally domesticated in China, appears to have been occasionally consumed at low levels by pastoralists inhabiting the far-flung regions of Siberia and southeastern Kazakhstan, possibly as early as the late third millennium. This initial uptake of millet coincided with the expansion of trans-regional networks across the steppe, when objects and ideas were first regularly exchanged over long-distances.

However, it was not until a thousand years later that millet became a regular feature of pastoralist diets. This timing coincides with the intensification of complex political structures at the transition to the Iron Age. Burgeoning socio-political confederations drove a marked increase in the exchange of costly prestige goods, which strengthened political networks - and facilitated the transfer of cultigens.

Wheat and Barley in the Trans-Urals

Despite taking part in these political networks, groups in the Trans-Urals invested in wheat and barley farming rather than millet. A dietary focus on wheat and barley may have been due to different farming techniques, greater water availability, or a higher value on these cultigens. "Our research suggests that cultigens were converted from a rare luxury during the Bronze Age to a medium demarcating elite participation in political networks during the Iron Age," states Cheryl Makarewicz of Kiel University.

Regional variation in millet consumption

While herding of livestock was widespread, not all regions adopted millet. In southwest Siberia, dietary intake was focused on pastoral animal products and locally available wild plants and fish. In contrast, the delayed adoption of millet by populations in Mongolia during the Late Iron Age coincides with the rise of the Xiongnu nomadic empire. "This is particularly interesting because it suggests that communities in Mongolia and Siberia opted out of the transition to millet agriculture, while continuing to engage with neighboring groups," explains Ventresca Miller.

This study shows the great potential of using the available isotope record to provide evidence for human dietary intake in areas where paleobotany is understudied. Further research should clarify the exact type of grains, for example broomcorn or foxtail millet, were fundamental to the shift in dietary intake and how networks of exchange linked different regions.

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Original publication:

Ventresca Miller and Makarewicz, Intensification in pastoralist cereal use coincides with the expansion of trans-regional networks in the Eurasian Steppe, Scientific Reports (2019). DOI: https://doi.org/10.1038/s41598-018-35758-w

 

Press release from Kiel University / Christian-Albrechts-Universität zu Kiel


Ancient feces reveal parasites in 8,000-year-old village of Çatalhöyük

Ancient feces reveal parasites in 8,000-year-old village of Çatalhöyük

parasites whipworm Çatalhöyük
South area excavation of Çatalhöyük, Turkey, in 2003. Author: Ziggurat, CC BY-SA 3.0

New research published today in the journal Antiquity reveals that ancient faeces from the prehistoric village of Çatalhöyük have provided the earliest archaeological evidence for intestinal parasite infection in the mainland Near East.

People first gave up hunting and gathering and turned to farming in the Near East, around 10,000 years ago. The settlement of Çatalhöyük is famous for being an incredibly well preserved early village founded around 7,100 BC. The population of Çatalhöyük were early farmers, growing crops such as wheat and barley, and herding sheep and goats.

"It has been suggested that this change in lifestyle resulted in a similar change in the types of diseases that affected them. As the village is one of the largest and most densely populated of its time, this study at Çatalhöyük helps us to understand that process better," says study lead Dr Piers Mitchell of Cambridge's Department of Archaeology.

The toilet was first invented in the 4th millennium BC in Mesopotamia, 3000 years later than when Çatalhöyük flourished. It is thought the people living at Çatalhöyük either went to the rubbish tip (midden) to open their bowels, or carried their faeces from their houses to the midden in a vessel or basket to dispose of them.

"We would expect this to have put the population at risk of diseases spread by contact with human faeces, and explains why they were vulnerable to contracting whipworm," says the study first author Marissa Ledger.

"As writing was only invented 3000 years after the time of Çatalhöyük, the people were unable to record what happened to them during their lives. This research enables us for the first time to imagine the symptoms felt by some of the prehistoric people living at Çatalhöyük who were infected by this parasite."

To look for the eggs of intestinal parasites, Cambridge researchers Mitchell, Ledger and Evilena Anastasiou used microscopy to study preserved pieces of human faeces (coprolites) from a rubbish tip, and soil formed from decomposed faeces recovered from the pelvic region of burials. The samples dated from 7,100-6150 BC.

To determine whether the coprolites excavated from the midden were from human or animal faeces, they were analysed for sterols and bile acids at the University of Bristol Mass Spectrometry Facility by Helen Mackay, Lisa Marie Shillito, and Ian Bull. This analysis demonstrated that the coprolites were of human origin.

Further microscopic analysis showed that eggs of whipworm were present in two of the coprolites, demonstrating that people from the prehistoric village were infected by this intestinal parasite.

"It was a special moment to identify parasite eggs over 8000 years old," said study co-author Evilena Anastasiou.

Whipworms are 3-5cm in length, and live on the lining of the intestines of the large bowel. Adult worms can live for 5 years. Male and female worms mate and their eggs are mixed in with the faeces. Whipworm is spread by the contamination of food or drink from human faeces that contain the worm eggs. A heavy infection with whipworm can lead to anaemia, diarrhoea, stunted growth and reduced intelligence in children.

"Now we need to find ancient faecal material from prehistoric hunter gathers in the Near East, to help us understand how this change in lifestyle affected their diseases." added Mitchell.

Read more


Genome analysis of yams reveals new cradle of crop domestication in West Africa

Genome analysis of yams reveals new cradle of crop domestication in West Africa

Yam genomics supports West Africa as a major cradle of crop domestication

yams
Wild yams, photo credits: Marco Schmidt [1], CC BY-SA 2.5
Yams as seen today in West Africa descended from a forest species, a new study finds. The results challenge the hypothesis that domestication of sub-Saharan African plants mostly arose in tropical savannahs. Critically, they also advance researchers' understanding of West African crops' domestication history, helping to identify a major cradle of domestication around the Niger River. One of the best-known domestication cradles in the world is the Fertile Crescent in the Middle East, where wheat, barley, oat, lentil and chickpea, among other crops, first appeared in the archaeological records.

The history of crop domestication is much less documented in sub-Saharan Africa, in part because archaeological studies are largely fragmentary. Previous studies of domestication in Africa suggest an origin encompassing a large area from Senegal to Somalia, while more recent studies have challenged this hypothesis - proposing a more restricted domestication origin near the Niger River Basin. To assess whether areas near the Niger Basin could be considered major hotspots of domestication, Nora Scarcelli and colleagues investigated the domestication of yam, a major staple crop originating from Africa. They used genome re-sequencing to analyze 167 "wild" and domesticated yam species from the country.

Their analysis, which included sophisticated statistical modeling, suggests that that cultivated yam was domesticated from a forest species, D. praehensilis, starting in the Niger River basin. Its domestication process involved adaptations to the open field environment and human selection that increased tuber size and starch content in the cultivated yam. The study further suggests that the Niger River region played a major role in African agriculture, comparable to the Fertile Crescent in the Near East.

 

Press release from the American Association for the Advancement of Science


barley Sweden Finland agriculture farming hunter gatherers Pitted Ware Culture

A 5,000-year-old barley grain discovered in Finland changes understanding of livelihoods

A 5,000-year-old barley grain discovered in Finland changes understanding of livelihoods

barley Sweden Finland agriculture farming hunter gatherers Pitted Ware Culture
Researchers determined the age of millennia-old barley grains using radiocarbon dating. Credit: photo by Santeri Vanhanen, CC-BY 4.0 licence

New findings reveal that hunter-gatherers took to farming already 5,000 years ago in eastern Sweden, and on the Aland Islands, located on the southwest coast of Finland

On the basis of prior research, representatives of the Pitted Ware Culture from the Stone Age have been known as hard-core sealers, or even Inuits of the Baltic Sea. Now, researchers have discovered barley and wheat grains in areas previously inhabited by this culture, leading to the conclusion that the Pitted Ware Culture adopted agriculture on a small scale.

A study carried out in cooperation with parties representing the discipline of archaeology and the Department of Chemistry at the University of Helsinki, as well as Swedish operators in the field of archaeology (The Archaeologists, a governmental consultant agency, and Arkeologikonsult, a business), found grains of barley and wheat in Pitted Ware settlements on Finland's Aland Islands and in the region of modern Stockholm.

The age of the grains was ascertained using radiocarbon dating. Based on the results, the grains originated in the period of the Pitted Ware culture, thus being approximately 4,300-5,300 years old. In addition to the cereal grains, the plant remnants found in the sites included hazelnut shells, apple seeds, tuberous roots of lesser celandine and rose hips.

The study suggests that small-scale farming was adopted by the Pitted Ware Culture by learning the trade from farmers of the Funnel Beaker Culture, the latter having expanded from continental Europe to Scandinavia.

Other archaeological artefacts are also evidence of close contact between these two cultures.

"The grains found on Aland are proof that the Pitted Ware Culture introduced cultivation to places where it had not yet been practised," says Santeri Vanhanen, a doctoral student of archaeology at the University of Helsinki.

In the study, the age of cereal grains found at the sites tagged with numbers in the map were determined with radiocarbon dating. These findings demonstrate that hunter-gatherers adopted farming on the Åland Islands on the southwestern coast of Finland and in eastern Sweden already 5,000 years ago. Credit: Santeri Vanhanen, CC-BY 4.0 licence

Cereal perhaps used to brew beer?

The 5,000-year-old barley grain found on Aland is the oldest grain of cereal ever found in Finland. The researchers also found a handful of barley and wheat grains a few hundred years younger, representing either common wheat or club wheat.

"We also dated one barley grain found in Raseborg, southern Finland. This grain and the other earliest grains found in mainland Finland date back some 3,500 years, some 1,500 years behind Aland according to current knowledge," Vanhanen explains.

In prior studies, it has been extremely difficult to demonstrate that the hunter-gatherer population would have adopted farming during recorded history, let alone in the Stone Age. Research on ancient DNA has in recent years proven that the spread of agriculture in Europe was almost exclusively down to migrants.

"We find it possible that this population, which was primarily specialised in marine hunting, continued to grow plants as the practice provided the community with social significance."

From time to time, an abundance of pig bones are found at Pitted Ware sites, even though pigs were not an important part of their daily nourishment. For instance, the bones of more than 30 pigs were found in a grave located on the island of Gotland.

"Members of the Pitted Ware culture may have held ritual feasts where pigs and cereal products were consumed. It's not inconceivable that grains might even have been used to brew beer, but the evidence is yet to be found," Vanhanen continues.

Santeri Vanhanen is a doctoral student of archaeology at the University of Helsinki. Credit: Marko Marila

Grain age determined through radiocarbon dating

The research relies primarily on archaeobotanical methodology, which helps examine plant remains preserved in archaeological sites. In this study, soil samples were collected from the sites, from which plant remains were extracted using a flotation method. The plant remains are charred; in other words, the grains and seeds have turned into carbon after having come to contact with fire.

Plant remains can be identified by examining them through a microscope and comparing them to modern plant parts. The age of individual grains can be determined with radiocarbon dating, based on the fractionation of the radioactive carbon-14 isotope. This way, the age of a grain aged several millennia can be determined with a precision of a few centuries.

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The study was published in the Scientific Reports journal on 20 March 2019. The research article, entitled "Maritime Hunter-Gatherers Adopt Cultivation at the Farming Extreme of Northern Europe 5000 Years Ago", is freely available on the journal's website: https://www.nature.com/articles/s41598-019-41293-z

This is how the Inuit culture of the Baltic Sea was born. Read more on the University of Helsinki website: https://www.helsinki.fi/en/news/language-culture/a-5000-year-old-barley-grain-discovered-in-aland-southern-finland-turns-researchers-understanding-of-ancient-northern-livelihoods-upside-down

Press release from the University of Helsinki