Thursday, May 25, 2017

Ancient DNA evidence shows hunter-gatherers and farmers were intimately linked


In human history, the transition from hunting and gathering to farming is a significant one. As such, hunter-gatherers and farmers are usually thought about as two entirely different sets of people. But researchers reporting new ancient DNA evidence in Current Biology on May 25 show that in the area we now recognize as Romania, at least, hunter-gatherers and farmers were living side by side, intermixing with each other, and having children.

"We expected some level of mixing between farmers and hunter-gatherers, given the archaeological evidence for contact among these communities," says Michael Hofreiter of University of Potsdam in Germany. "However, we were fascinated by the high levels of integration between the two communities as reconstructed from our ancient DNA data."

The findings add evidence to a longstanding debate about how the Neolithic transition, when people gave up hunting and gathering for farming, actually occurred, the researchers say. In those debates, the question has often been about whether the movement of people or the movement of ideas drove the transition.

Earlier evidence suggested that the Neolithic transition in Western Europe occurred mostly through the movement of people, whereas cultural diffusion played a larger role to the east, in Latvia and Ukraine. The researchers in the new study were interested in Romania because it lies between these two areas, presenting some of the most compelling archaeological evidence for contact between incoming farmers and local hunter-gatherers.

Indeed, the new findings show that the relationship between hunter-gatherers and farmers in the Danube basin can be more nuanced and complex. The movement of people and the spread of culture aren't mutually exclusive ideas, the researchers say, "but merely the ends of a continuum."

The researchers came to this conclusion after recovering four ancient human genomes from Romania spanning a time transect between 8.8 thousand and 5.4 thousand years ago. The researchers also analyzed two Mesolithic (hunter-gatherer) genomes from Spain to provide further context.

The DNA revealed that the Romanian genomes from thousands of years ago had significant ancestry from Western hunter-gatherers. However, they also had a lesser but still sizeable contribution from Anatolian farmers, suggesting multiple admixture events between hunter-gatherers and farmers. An analysis of the bones also showed they ate a varied diet, with a combination of terrestrial and aquatic sources.

"Our study shows that such contacts between hunter-gatherers and farmers went beyond the exchange of food and artefacts," Hofreiter says. "As data from different regions accumulate, we see a gradient across Europe, with increasing mixing of hunter-gatherers and farmers as we go east and north. Whilst we still do not know the drivers of this gradient, we can speculate that, as farmers encountered more challenging climatic conditions, they started interacting more with local hunter-gatherers. These increased contacts, which are also evident in the archaeological record, led to genetic mixing, implying a high level of integration between very different people."

The findings are a reminder that the relationships within and among people in different places and at different times aren't simple. It's often said that farmers moved in and outcompeted hunter-gatherers with little interaction between the two. But the truth is surely much richer and more varied than that. In some places, as the new evidence shows, incoming farmers and local hunter-gatherers interacted and mixed to a great extent. They lived together, despite large cultural differences.

Understanding the reasons for why the interactions between these different people led to such varied outcomes, Hofreiter says, is the next big step. The researchers say they now hope to use ancient DNA evidence to add more chapters to the story as they explore the Neolithic transition as it occurred in other parts of the world, outside of Europe.


Wednesday, May 24, 2017

Ochre use by Middle Stone Age humans in Porc-Epic cave persisted over thousands of years



Middle Stone Age humans in the Porc-Epic cave likely used ochre over at least 4,500 years, according to a study published May 24, 2017 in the open-access journal PLOS ONE by Daniela Rosso from the University of Barcelona, Spain, and the University of Bordeaux, France, and colleagues.

Images of ochre, the iron-rich rock characterized by a red or yellow color, that was found at many Middle Stone Age sites.

CREDIT
Rosso et al (2017)

Ochre, an iron-rich rock characterized by a red or yellow color, is found at many Middle Stone Age sites. The largest known East African collection of Middle Stone Age ochre, found at Porc-Epic Cave in Ethiopia, weighs around 40kg and is thought to date to ca. 40,000 years ago. The authors of the present study conducted a detailed analysis of 3792 pieces of ochre, using microscopy and experimental reproduction of grinding techniques to assess how the ochre was processed and used over a 4,500-year timespan.

The researchers found that the cave inhabitants appeared to have persistently acquired, processed, and used the same types of ochre during this period.

Overall the inhabitants of the cave seem to have processed almost half of the ochre pieces, although the proportion of ochre which had been modified decreased progressively over the period. Whilst flaking and scraping of ochre pieces appeared to have become more common over time, the authors noted a reduction in the proportion of pieces which underwent grinding. The gradual nature of shifts in preferred processing techniques may indicate that they resulted from cultural drift within this practice.

Intensively modified ochre pieces show ground facets likely produced with different types of grindstones, at different times. According to the authors, these pieces were probably curated and processed for the production of small amounts of ochre powder. This is consistent with use in symbolic activities, such as the production of patterns or body painting, although a use for utilitarian activities cannot be discarded.

Whilst the increase of ochre use in certain layers could be explained by refining the dating of the sequence and acquiring environmental data, these authors state that their analysis of ochre treatment seems to reflect a "cohesive behavioral system shared by all community members and consistently transmitted through time."

Groundbreaking discovery of early human life in ancient Peru


A-tisket, A-tasket. You can tell a lot from a basket. Especially if it comes from the ruins of an ancient civilization inhabited by humans nearly 15,000 years ago during the Late Pleistocene and Early Holocene ages.


Basket remnants retrieved from the site were made from diverse materials including a local reed that is still used today by modern basket makers. More elaborate baskets included segments made from domesticated cotton and were colored using some of the oldest dyes known in the New World. 
CREDIT
Florida Atlantic University's Harbor Branch Oceanographic Institute

An archeologist from Florida Atlantic University's Harbor Branch Oceanographic Institute is among a team of scientists who made a groundbreaking discovery in Huaca Prieta in coastal Peru - home to one of the earliest and largest pyramids in South America. Hundreds of thousands of artifacts, including intricate and elaborate hand-woven baskets excavated between 2007 and 2013 in Huaca Prieta, reveal that early humans in that region were a lot more advanced than originally thought and had very complex social networks.

For decades, archeologists exploring Peru have argued about the origins and emergence of complex society in Peru. Did it first happen in the highlands with groups who were dependent on agriculture or did it happen along the coast with groups who were dependent on seafood? Evidence from the site indicates a more rapid development of cultural complexity along the Pacific coast than previously thought as published in Science Advances.

"The mounds of artifacts retrieved from Huaca Prieta include food remains, stone tools and other cultural features such as ornate baskets and textiles, which really raise questions about the pace of the development of early humans in that region and their level of knowledge and the technology they used to exploit resources from both the land and the sea," said James M. Adovasio, Ph.D., D.Sc., co-author of the study and a world acclaimed archaeologist at FAU's Harbor Branch, who is the foremost authority on ancient textiles and materials such as those used in basketry.

Among the artifacts excavated are tools used to capture deep-sea fish-like herring. The variety of hooks they used indicate the diversity of fishing that took place at that time and almost certainly the use of boats that could withstand rough waters. These ancient peoples managed to develop a very efficient means of extracting seaside resources and devised complex techniques to collect those resources. They also combined their exploitation of maritime economy with growing crops like chili pepper, squash, avocado and some form of a medicinal plant on land in a way that produced a large economic surplus.

"These strings of events that we have uncovered demonstrate that these people had a remarkable capacity to utilize different types of food resources, which led to a larger society size and everything that goes along with it such as the emergence of bureaucracy and highly organized religion," said Adovasio.

Advosasio's focus of the excavation was on the extensive collection of basket remnants retrieved from the site, which were made from diverse materials including a local reed that is still used today by modern basket makers. More elaborate baskets included segments made from domesticated cotton and were colored using some of the oldest dyes known in the New World.

"To make these complicated textiles and baskets indicates that there was a standardized or organized manufacturing process in place and that all of these artifacts were much fancier than they needed to be for that time period," said Adovasio. "Like so many of the materials that were excavated, even the baskets reflect a level of complexity that signals a more sophisticated society as well as the desire for and a means for showing social stature. All of these things together tell us that these early humans were engaged in very complicated social relationships with each other and that these fancy objects all bespeak that kind of social messaging."

The late archeologist Junius B. Bird was the first to excavate Huaca Prieta in the late 1940s after World War II and his original collection is housed in the American Museum of Natural History in New York. This latest excavation is only the second one to take place at this site, but this time using state-of-the-art archeological technology. This recent excavation took approximately six years to complete and included a total of 32 excavation units and trenches, 32 test pits, and 80 geological cores that were placed on, around and between the Huaca Prieta and Paredones mounds as well as other sites. These artifacts are now housed in a museum in Lima, Peru.

Shared genetic heritage from Sicily to Cyprus



A new genomic study on southern Mediterranean reveals a genetic continuity across geographic and national borders. The map shows the sampling locations included in the study, with presence of Albanian, Greek or Italian languages.
Credit: Sarno et al. DOI 10.1038/s41598-017-01802-4
 
The study -- coordinated by the Human Biodiversity and Population Genomics group at the Department of Biological, Geological and Environmental Sciences (BiGeA) of the University of Bologna and funded by the National Geographic Society -- describes the genetic fingerprints of the Mediterranean people with high-density genomic markers and a wide sample of modern populations from Sicily and Southern Italy. Their genetic profiles were analyzed to reconstruct the combination of ancestry components and the demographic history of the region.

As one would expect, populations inhabiting the southeastern shores of Europe are the result of a complex, multi-layered history. One of these layers corresponds to a shared genetic background, extending from Sicily to Cyprus and involving Crete, the Aegean islands and Anatolia. "This shared Mediterranean ancestry possibly traces back to prehistoric times, as the result of multiple migration waves, with peaks during the Neolithic and the Bronze Age," says Stefania Sarno, researcher from the University of Bologna and lead author of the study. Apparently, the ancient Greek expansions (during the Magna Graecia foundation) were only one of the last events in a long history of East-West movements, where the Mediterranean Sea served as a preferential crossroads for the circulation of genes and cultures.

A new perspective for the diffusion of Indo-European languages

One of the most intriguing layers hidden in the Mediterranean genetic landscape involves an important Bronze Age contribution from a Caucasus (or Caucasus-like) source, accompanied by the virtual absence of the typical "Pontic-Caspian" genetic component from the Asian steppe. The latter is a very characteristic genetic signal well represented in North-Central and Eastern Europe, which previous studies associated with the introduction of Indo-European languages to the continent. "These new genomic results from the Mediterranean open a new chapter for the study of the prehistoric movements behind the diffusion of the most represented language family in Europe. The spread of these languages in the Southern regions, where Indo-European languages like Italian, Greek and Albanian are spoken nowadays, cannot be explained with the major contribution from the steppe alone," adds Chiara Barbieri from the Max Planck Institute for the Science of Human History in Jena.

Linguistic and cultural isolates

The current genetic study also focuses on more recent historical layers that contributed to the present-day genetic makeup of the populations sampled, in particular in the cases of long-standing, non-Italian-speaking communities in Italy. For example, mainland Greece and Albania seem to have acquired additional genetic contributions during historic times, most likely related to the Slavic migrations in the Balkans. This recent Balkan genetic ancestry is still evident in some ethno-linguistic minorities of Sicily and Southern Italy, such as the Albanian-speaking Arbereshe. The Arbreshe migrated from Albania to Italy at the end of the Middle Ages and experienced geographic and cultural isolation, which played a part in their distinctive genetic composition.

A different case study is that of Greek-speaking communities from Southern Italy. The genetic features of these groups are compatible with the antiquity of their settlement and with a high cultural permeability with neighboring populations, combined with drift and effects of geographic isolation, as in the case of Calabrian Greeks. "The study of linguistic and cultural isolates in Italy proved to be important to understand our history and our demography," says Alessio Boattini, geneticist and anthropologist from the University of Bologna. "The cases of the Albanian- and Greek-speaking communities of Southern Italy help to shed light into the formation of these cultural and linguistic identities."

"Overall, the study illustrates how both genetic and cultural viewpoints can inform our knowledge of the complex dynamics behind the formation of our Mediterranean heritage, especially in contexts of extensive -- both geographically and temporally -- admixture," says Davide Pettener, professor of Anthropology from the University of Bologna. "These results," adds Prof. Donata Luiselli, who co-led the project, "will be further developed in future studies integrating data from other disciplines, in particular linguistics, archeology and palaeogenomics, with the study of ancient DNA from archaeological remains."



Viking army camp uncovered by archaeologists in England



A huge camp which was home to thousands of Vikings as they prepared to conquer England in the late ninth century has been uncovered by archaeologists.

Established in Torksey, on the banks of the River Trent in Lincolnshire, the camp was used as the Vikings' defensive and strategic position during the winter months.

The research, conducted by archaeologists at the Universities of Sheffield and York, has revealed how the camp was used by thousands of Viking warriors, women and children who lived there temporarily in tented accommodation.

They also used the site as a base to repair ships, melt down stolen loot, manufacture, trade and play games.

Professor Dawn Hadley, who led the research from the University of Sheffield's Department of Archaeology said: "The Vikings' camp at Torksey was much more than just a handful of hardy warriors -- this was a huge base, larger than most contemporary towns, complete with traders, families, feasting, and entertainment.

"From what has been found at the site, we know they were repairing their boats there and melting down looted gold and silver to make ingots -- or bars of metal they used to trade.

"Metal detectorists have also found more than 300 lead game pieces, suggesting the Vikings, including, women and children, were spending a lot of time playing games to pass the time, waiting for spring and the start of their next offensive."

The findings have now been used to create a virtual reality experience giving users an opportunity to experience what life was like in a Viking army camp.

The virtual reality experience has been developed by researchers at the University of York and is part of an exhibition at the Yorkshire Museum that opens on Friday (19 May 2017).

All the scenes featured in the virtual reality experience are based on real objects found by archaeologists and metal detectorists at Torksey.

Professor Julian Richards, from the Department of Archaeology at the University of York, said: "These extraordinary images offer a fascinating snap shot of life at a time of great upheaval in Britain.

"The Vikings had previously often raided exposed coastal monasteries and returned to Scandinavia in winter, but in the later ninth century they came in larger numbers, and decided to stay. This sent a very clear message that they now planned not only to loot and raid -- but to control and conquer."

Dr Gareth Beale from York's Digital Creativity Labs added: "The new research by the Universities of Sheffield and York has been used to create the most realistic images of the camp to date, based on real findings. These images are also believed to be the most realistic Virtual Reality ever created anywhere of the Viking world."

The exact location and scale of the camp in Lincolnshire has been debated for many years, but now the research by Sheffield and York is beginning to reveal the true extent of the camp. It is now thought to be at least 55 hectares in size, bigger than many towns and cities of the time, including York.

There have also been more than a thousand finds by metal detectorists and archaeologists, including over 300 coins. They include more than 100 Arabic silver coins which would have come to the area through established Viking trade routes.

More than 50 pieces of chopped up silver, including brooch fragments and ingots have been found along with rare hackgold. Evidence has been found that these items were being processed at the camp -- chopped up to be melted down. Other finds include the 300 gaming pieces, iron tools, spindle whorls, needles and fishing weights.

Using landscape analysis, the research has been able to reveal the topography of the camp. With the River Trent to the west and surrounding land prone to flooding to this day, its strength as a defensive position becomes clear.


The beginnings of agriculture



The beginnings of agriculture changed human history and has fascinated scientists for centuries.
Researchers from the Grantham Centre for Sustainable Futures at the University of Sheffield have shed light on how hunter-gatherers first began farming and how crops were domesticated to depend on humans.

Domesticated crops have been transformed almost beyond recognition in comparison with their wild relatives -- a change that happened during the early stages of farming in the Stone Age.

For grain crops like cereals, the hallmark of domestication is the loss of natural seed dispersal -- seeds no longer fall off plants but have become dependent on humans or machines to spread them.

Professor Colin Osborne, from the Grantham Centre for Sustainable Futures at the University of Sheffield, said: "We know very little about how agriculture began, because it happened 10,000 years ago -- that's why a number of mysteries are unresolved. For example why hunter-gatherers first began farming, and how were crops domesticated to depend on people.

"One controversy in this area is about the extent to which ancient peoples knew they were domesticating crops. Did they know they were breeding domestication characteristics into crops, or did these characteristics just evolve as the first farmers sowed wild plants into cultivated soil, and tended and harvested them?"

The new research, published in the journal Evolution Letters, shows the impact of domestication on vegetable seed size.

Any selective breeding of vegetables by early farmers would have acted on the leaves, stems or roots that were eaten as food, but should not have directly affected seed size.

Instead, any changes in vegetable seed size must have arisen from natural selection acting on these crops in cultivated fields, or from genetic links to changes in another characteristic like plant or organ size. In the last instance, people might have bred crops to become bigger, and larger seeds would have come along unintentionally.

The University of Sheffield researchers gathered seed size data from a range of crops and found strong evidence for a general enlargement of seeds due to domestication.

They discovered domesticated maize seeds are 15 times bigger than the wild form, soybean seeds are seven times bigger. Wheat, barley and other grain crops had more modest increases in size (60 per cent for barley and 15 per cent for emmer wheat) but these changes are important if they translate into yield.

"We found strong evidence for a general enlargement of seeds due to domestication across seven vegetable species," said Professor Osborne.

"This is especially stunning in a crop like a sweet potato, where people don't even plant seeds, let alone harvest them. The size of this domestication effect falls completely within the range seen in cereals and pulse grains like lentils and beans, raising the possibility that at least part of the seed enlargement in these crops also evolved during domestication without deliberate foresight from early farmers."

Professor Osborne added: "Our findings have important implications for understanding how crops evolved, because they mean that major changes in our staple crops could have arisen without deliberate foresight by early farmers.

"This means that unconscious selection was probably more important in the genesis of our food plants than previously realised. Early increases in the yields of crops might well have evolved in farmers' fields rather than being bred artificially.

Thursday, May 11, 2017

India: Scientists have identified migrating humans from Africa, Iran and Central Asia over a period of 50,000 years


In addition to its vast patchwork of languages, cultures and religions, the Indian Subcontinent also harbours huge genetic diversity. Where did its peoples originate? This is an area of huge controversy among scholars and scientists. A University of Huddersfield PhD student is lead author of an article that tries to answer the question using genetic evidence.

A problem confronting archaeogenetic research into the origins of Indian populations is that there is a dearth of sources, such as preserved skeletal remains that can provide ancient DNA samples. Marina Silva and her co-authors have instead focused on people alive in the Subcontinent today.

They show that some genetic lineages in South Asia are very ancient. The earliest populations were hunter-gatherers who arrived from Africa, where modern humans arose, more than 50,000 years ago. But further waves of settlement came from the direction of Iran, after the last Ice Age ended 10-20,000 years ago, and with the spread of early farming.

These ancient signatures are most clearly seen in the mitochondrial DNA, which tracks the female line of descent. But Y-chromosome variation, which tracks the male line, is very different. Here the major signatures are much more recent. Most controversially, there is a strong signal of immigration from Central Asia, less than 5,000 years ago.

This looks like a sign of the arrival of the first Indo-European speakers, who arose amongst the Bronze Age peoples of the grasslands north of the Caucasus, between the Black and Caspian Seas. They were male-dominated, mobile pastoralists who had domesticated the horse -- and spoke what ultimately became Sanskrit, the language of classical Hinduism -- which more than 200 years ago linguists showed is ultimately related to classical Greek and Latin.

Migrations from the same source also shaped the settlement of Europe and its languages, and this has been the subject of most recent research, said Marina Silva. She has tried to tip the balance back towards India, and her findings are discussed in the article titled A genetic chronology for the Indian Subcontinent points to heavily sex-biased dispersals. It appears in the journal BMC Evolutionary Biology.