Lactose tolerance spread throughout Europe in only a few thousand years

Palaeogeneticists at Mainz University have found evidence of lactase persistence in only a small proportion of human bones from the Bronze Age battlefield in the Tollense valley

JOHANNES GUTENBERG UNIVERSITAET MAINZ

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IMAGE: BRONZE AGE SKULL IN SITU IN THE TOLLENSE VALLEY. view more 

CREDIT: PHOTO/©: STEFAN SAUER/TOLLENSE VALLEY PROJECT

The human ability to digest the milk sugar lactose after infancy spread throughout Central Europe in only a few thousand years. This is the conclusion reached by an international research team led by Johannes Gutenberg University Mainz (JGU). The researchers analyzed genetic material from the bones of individuals who had fallen in a conflict around 1200 B.C. on the banks of the Tollense, a river in the present-day German state of Mecklenburg-Western Pomerania, and report their findings in Current Biology this week. The researchers found that only around one in eight of the assumed warriors had a gene variant that enabled them to break down the lactose in milk. "Of the present-day population living in this same area, around 90 percent have this lactase persistence," explained population geneticist Professor Joachim Burger of JGU, the lead author of the study. "This is a huge difference when you consider that there cannot be many more than 120 human generations between then and today." Aside from lactase persistence and a few other genetic variants, the genomes of the Tollense people are similar to that of today's inhabitants of northern Germany and the Baltic Sea region.

"The only way to explain this difference between these Bronze Age people and those of today is very strong natural selection," emphasized biologist Professor Daniel Wegmann of the University of Fribourg in Switzerland, who also played a leading role in the study. "We conclude that over the past 3,000 years, lactase-persistent individuals had more children or, alternatively, those children had better chances of survival than those without this trait." The researchers calculate a remarkable selective advantage: "In each generation lactase-persistent individuals have a six percent greater chance of surviving to reproductive age than non-lactase-persistent individuals," added Professor Joachim Burger.

Back in 2007, Burger and his team established that almost none of the first sedentary farmers in Europe were lactase-persistent. "It is astonishing that at the time of the battle at the Tollense, more than 4,000 years after the introduction of agriculture in Europe, lactase persistence in adults was still so rare," said Burger. However, there is as yet no definitive answer to the question: Why did being able to digest the sugar in milk after infancy provide such a big evolutionary advantage? "With milk being a high-energy, relatively uncontamined drink, its ingestion may have provided greater chances of survival during food shortages or when supplies of drinking water were contaminated. Particularly during early childhood, in the years shortly after weaning, this factor often may have been decisive amongst prehistoric populations," Burger concluded.

The study, which was funded by the German Federal Ministry of Education and Research (BMBF) and the German Research Foundation (DFG), also involved analyzing the genetic material in Bronze Age bones found in Eastern and South-Eastern Europe for comparison. The scientists found that these also showed low frequencies of lactase persistence. Even in bones from individuals from the Eastern European steppes, where previous studies had suspected adult lactase persistence may have originated, the trait was completely absent.

The conflict in the Tollense valley is considered the oldest known battle in Europe. Remains were first discovered there in the 1990s. For over ten years now, archaeologists have been systematically searching a kilometer-long section along the river. So far, the bones of more than 100 individuals have been discovered, many of them exhibiting signs of violent combat. Many still contain arrowheads, while some skulls look to have been crushed by blunt objects. Several thousand men are estimated to have been involved in the conflict, some of whom may have been on horseback.

How climate change led to fall of ancient civilization

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IMAGE: THIS FIGURE SHOWS THE SETTLEMENTS OF THE INDUS VALLEY CIVILIZATION DURING DIFFERENT PHASES OF ITS EVOLUTION. RIT ASSISTANT PROFESSOR NISHANT MALIK DEVELOPED A MATHEMATICAL METHOD THAT SHOWS CLIMATE CHANGE LIKELY... view more 

CREDIT: RIT

A Rochester Institute of Technology researcher developed a mathematical method that shows climate change likely caused the rise and fall of an ancient civilization. In an article recently featured in the journal Chaos: An Interdisciplinary Journal of Nonlinear Science, Nishant Malik, assistant professor in RIT's School of Mathematical Sciences, outlined the new technique he developed and showed how shifting monsoon patterns led to the demise of the Indus Valley Civilization, a Bronze Age civilization contemporary to Mesopotamia and ancient Egypt.

Malik developed a method to study paleoclimate time series, sets of data that tell us about past climates using indirect observations. For example, by measuring the presence of a particular isotope in stalagmites from a cave in South Asia, scientists were able to develop a record of monsoon rainfall in the region for the past 5,700 years. But as Malik notes, studying paleoclimate time series poses several problems that make it challenging to analyze them with mathematical tools typically used to understand climate.

"Usually the data we get when analyzing paleoclimate is a short time series with noise and uncertainty in it," said Malik. "As far as mathematics and climate is concerned, the tool we use very often in understanding climate and weather is dynamical systems. But dynamical systems theory is harder to apply to paleoclimate data. This new method can find transitions in the most challenging time series, including paleoclimate, which are short, have some amount of uncertainty and have noise in them."

There are several theories about why the Indus Valley Civilization declined--including invasion by nomadic Indo-Aryans and earthquakes--but climate change appears to be the most likely scenario. But until Malik applied his hybrid approach-- rooted in dynamical systems but also draws on methods from the fields of machine learning and information theory--there was no mathematical proof. His analysis showed there was a major shift in monsoon patterns just before the dawn of this civilization and that the pattern reversed course right before it declined, indicating it was in fact climate change that caused the fall.

Malik said he hopes the method will allow scientists to develop more automated methods of finding transitions in paleoclimate data and leads to additional important historical discoveries. The full text of the study is published in Chaos: An Interdisciplinary Journal of Nonlinear Science.

Drone survey reveals large earthwork at ancestral Wichita site in Kansas

Results show possible council circle at what may be Etzanoa near Wichita

DARTMOUTH COLLEGE

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IMAGE: LEFT: DRONE-ACQUIRED ORTHOIMAGE OF THE SITE SHOWING MAJOR FEATURES DISCUSSED IN THE PAPER. RIGHT: THERMAL IMAGES MOSAIC COLLECTED FROM 11:15 PM-12:15 AM. (IMAGES FROM FIGURE 6 OF THE STUDY).... view more 

CREDIT: IMAGES BY JESSE CASANA, ELISE JAKOBY LAUGIER, AND AUSTIN CHAD HILL.

A Dartmouth-led study using multisensor drones has revealed a large circular earthwork at what may be Etzanoa, an archaeological site near Wichita, Kansas. Archaeologists speculate that the site was visited by a Spanish expedition, led by Juan de Oñate, a controversial conquistador, in 1601. The earthwork may be the remains of a so-called "council circle," as it is similar to several other circular earthworks in the region, according to the study's findings published in American Antiquity.

"Our findings demonstrate that undiscovered monumental earthworks may still exist in the Great Plains. You just need a different archeological approach to recognize them," explained lead author, Jesse J. Casana, a professor and chair of the department of anthropology at Dartmouth. "Our results are promising in suggesting that there may be many other impressive archaeological features that have not yet been documented, if we look hard enough," he added.

Archaeological features have various thermal effects. After the ground cools at nighttime, things below the ground cool and emit heat at different rates, enabling researchers to identify features based on thermal infrared radiation. The researchers obtained thermal and multispectral imagery of the site using drones.

The 18-hectare area of the site where the drone survey was conducted is currently home to a ranch property in the lower Walnut River valley, which has been used as a pasture. Topographically, the area is flat with no visible archaeological features. Yet, imagery shows that underground there is an ancient, circular shaped ditch measuring 50 meters wide and approximately 2 meters thick that has been infilled. As the soil erodes, it fills up the ditch with a different type of soil than was there before, and therefore retains water differently giving it unique thermal properties. The water retention levels also impact vegetation. Using near-infrared imagery, the researchers were able to identify areas that had been infilled because grass growth was more vigorous. As the study reports, the results provide evidence for what may have been a "single, sprawling population center" back in its day.

To confirm that the findings were not an anomaly, the team collected a time series of aerial and satellite images of the area from the U.S. Department of Agriculture and other federal agencies. They found that the circular feature was "faintly visible in June 2015 and July 2017 but not in June 2012 or February 2017."

The debate is widespread as to what council circles were used for, whether they were astronomical in nature or made for ceremonial, political and/or defense purposes. Casana added, "While we may never know what the council circles were used for or their significance, new archaeological methods allow us to see that people made these earthworks."

Bronze Age tradition of keeping human remains

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IMAGE: UNIQUE PRONGED BRONZE OBJECT FROM THE WILSFORD G58 BURIAL FOUND ALONGSIDE THE HUMAN BONE MUSICAL INSTRUMENT. view more 

CREDIT: WILTSHIRE MUSEUM, COPYRIGHT UNIVERSITY OF BIRMINGHAM/DAVID BUKACHIT

Using radiocarbon dating and CT scanning to study ancient bones, researchers have uncovered for the first time a Bronze Age tradition of retaining and curating human remains as relics over several generations.

While the findings, led by the University of Bristol and published in the journal Antiquity, may seem eerie or even gruesome by today's convention, they indicate a tangible way of honouring and remembering known individuals between close communities and generations some 4,500 years ago.

"Even in modern secular societies, human remains are seen as particularly powerful objects, and this seems to hold true for people of the Bronze Age. However, they treated and interacted with the dead in ways which are inconceivably macabre to us today," said lead author, Dr Thomas Booth, who carried out the radiocarbon dating work at the university's School of Chemistry.

"After radiocarbon dating Bronze Age human remains alongside other materials buried with them, we found many of the partial remains had been buried a significant time after the person had died, suggesting a tradition of retaining and curating human remains."

"People seem to have curated the remains of people who had lived within living or cultural memory, and who likely played an important role in their life or their communities, or with whom they had a well-defined relationship, whether that was direct family, a tradesperson, a friend or even an enemy, so they had a relic to remember and perhaps tell stories about them," said Dr Booth.

In one extraordinary case from Wiltshire, a human thigh bone had been crafted to make a musical instrument and included as a grave good with the burial of a man found close to Stonehenge. The carefully carved and polished artefact, found with other items, including stone and bronze axes, a bone plate, a tusk, and a unique ceremonial pronged object, are displayed in the Wiltshire Museum. Radiocarbon dating of this musical instrument suggests it belonged to someone this person knew during their lifetime.

"Although fragments of human bone were included as grave goods with the dead, they were also kept in the homes of the living, buried under house floors and even placed on display", said Professor Joanna Brück, principal investigator on the project, and Visiting Professor at the University of Bristol's Department of Anthropology and Archaeology.

"This suggests that Bronze Age people did not view human remains with the sense of horror or disgust that we might feel today."

The team also used microcomputed tomography (micro-CT) at the Natural History Museum to look at microscopic changes to the bone produced by bacteria, to get an indication of how the body was treated while it was decomposing.

"The micro-CT scanning suggested these bones had come from bodies that had been treated in similar ways to what we see for Bronze Age human remains more generally. Some had been cremated before being split up, some bones were exhumed after burial, and some had been de-fleshed by being left to decompose on the ground," Dr Booth said.

"This suggests that there was no established protocol for the treatment of bodies whose remains were destined to be curated, and the decisions and rites leading to the curation of their remains took place afterwards."

There is already evidence people living in Britain during the Bronze Age practiced a range of funerary rites, including primary burial, excarnation, cremation and mummification. However, this research reveals the dead were encountered not just in a funerary context, but that human remains were regularly kept and circulated amongst the living.

These findings may tell us something about how Bronze Age communities in Britain drew upon memory and the past to create their own social identities. Unlike our regard for saintly relics today, they do not seem to have focused on very old human remains and the distant past of ancestors, rather they were concerned with the remains of those within living memory.

"This study really highlights the strangeness and perhaps the unknowable nature of the distant past from a present-day perspective. It seems the power of these human remains lay in the way they referenced tangible relationships between people in these communities and not as a way of connecting people with a distant mythical past," said Dr Booth.

Helminth infections common in Medieval Europe

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IMAGE: PHOTOMICROGRAPH OF A TRICHURIS TRICHIURA EGG FROM AN ARCHAEOLOGICAL DEPOSIT. view more 

CREDIT: ADRIAN SMITH AND PATRIK FLAMMER, UNIVERSITY OF OXFORD, UK

Although helminth infections--including tapeworms and roundworms--are among the world's top neglected diseases, they are no longer endemic in Europe. However, researchers reporting in PLOS Neglected Tropical Diseases report that these infections were common in Medieval Europe, according to grave samples analyzed from across the continent.

Helminths are parasitic worms and they infect an estimated 1.5 billion people worldwide. The worms are transmitted through eggs that are present in human feces and can contaminate soil and water. While some infections cause only mild symptoms, others are associated with chronic malnutrition and physical impairment, particularly in children.

In the new work, Adrian Smith of the University of Oxford, UK, and colleagues analyzed 589 grave samples from 7 European sites dated between 680 and 1700 CE. Samples were taken from the pelvises of skeletons. Data associated with the sites allowed them to assess the influence of age, sex and community size on helminth infection rates.

Two soil transmitted nematodes--Ascaris spp. and Trichuris trichiura--were identified at all locations, and two food derived cestodes--Diphyllobothrium latum and Taenia spp.--were found at 4 sites. No helminths were found in any control samples. The rates of nematode infection in the medieval population were estimated at 8.5% (range 1.5%-25.6%) for T. trichiura and 25.1% (range 9.3%-42.9%) for Ascaris, similar rates to those seen in modern endemically infected populations. There were no differences in infection rates by sex or community population size, but infection rates were most common among children.

"Since the prevalence of medieval soil transmitted helminth infections mirror those in modern endemic countries, the factors affecting helminth decline in Europe may also inform modern intervention campaigns," the researchers say. "The parasites in past communities can tell us a lot about living conditions including hygiene, sanitation and even culinary practices."

Ceramic cooking pots record history of ancient food practices

Analysing three components of ceramic cooking pots -- charred remains, inner surface residues and lipids absorbed within the ceramic walls -- may help archaeologists uncover detailed timelines of culinary cooking practices used by ancient civilizations. The findings, from a year-long cooking experiment, are published this week in Scientific Reports.

Led by scientists Melanie Miller, Helen Whelton and Jillian Swift, a team of seven archaeologists repetitively cooked the same ingredients in unglazed ceramic pots once per week over the course of one year, then changed recipes for the final cooking event to study whether remaining residues may represent the last meal cooked or an accumulation of cooking events over the total amount of time a vessel has been used. Recipes included ingredients such as wheat, maize and venison.

Chemical analysis of the carbon and nitrogen isotopic values of residues present in the ceramic pots, contributed by carbohydrates, lipids and proteins from the meals cooked, suggest that the remains of burnt food left within each vessel represent the final ingredients and change with each meal. The chemical composition of the thin residue layer formed on the inside surface of the cooking pot and in most direct contact with the food when cooking represents a mixture of previous meals, but most closely resembles that of the final meal. Further analysis also suggests that lipids are absorbed into the walls of the ceramic vessel over a number of cooking events and are not immediately replaced by the new recipes but are instead slowly replaced over time, representing a mixture of the ingredients cooked over the total amount of time the vessel was in use.

Analysis of all three residues reveal cooking events across different time scales for ceramic vessels and may enable archaeologists to better understand the various resources used by ancient cultures and to estimate the lifespan of pottery used in meal preparation.

Atlantic sturgeon in the king's pantry -- unique discovery in Baltic sea wreck from 1495

LUND UNIVERSITY

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Researchers at Lund University in Sweden can now reveal what the Danish King Hans had planned to offer when laying claim to the Swedish throne in 1495: a two-metre-long Atlantic sturgeon. The well-preserved fish remains were found in a wreck on the bottom of the Baltic Sea last year, and species identification was made possible through DNA analysis.

At midsummer in 1495, the Danish King Hans was en route from Copenhagen to Kalmar, Sweden, on the royal flagship Gribshunden. Onboard were the most prestigious goods the Danish royal court could provide, but then, the trip was also very important. King Hans was going to meet Sten Sture the Elder (he hoped) to lay claim to the Swedish throne. It was important to demonstrate both power and grandeur.

However, when the ship was level with Ronneby in Blekinge, which was Danish territory at the time, a fire broke out on board and Gribshunden sank. The King himself was not on board that night, however, both crew and cargo sank with the ship to the sea floor, where it has lain ever since.

Thanks to the unique environment of the Baltic Sea - with oxygen-free seabeds, low salinity and an absence of shipworms - the wreck was particularly well preserved when it was discovered approximately fifty years ago, and has provided researchers with a unique insight into life on board a royal ship in the late Middle Ages. In addition, researchers now also know what was in the royal pantry - the wooden barrel discovered last year, with fish remains inside.

"It is a really thrilling discovery, as you do not ordinarily find fish in a barrel in this way. For me, as an osteologist, it has been very exciting to work with", says Stella Macheridis, researcher at the Department of Archaeology and Ancient History at Lund University.

When the remains were discovered it was possible to see that they came from a sturgeon pretty early on due to the special bony plates, the scutes. However, researchers were unsure which species it was. Up until relatively recently, it was believed to be the European sturgeon found in the Baltic Sea at the time. However, the DNA analysis revealed it was the Atlantic variety with which King Hans planned on impressing the Swedes. Researchers have also been able to estimate the length of the sturgeon - two metres - as well as demonstrate how it was cut.

For Maria C Hansson, molecular biologist at Lund University, and the researcher who carried out the DNA analysis, the discovery is of major significance, particularly for her own research on the environment of the Baltic Sea.

"For me, this has been a glimpse of what the Baltic Sea looked like before we interfered with it. Now we know that the Atlantic sturgeon was presumably part of the ecosystem. I think there could be great potential in using underwater DNA in this way to be able to recreate what it looked like previously", she says.

The Atlantic sturgeon is currently an endangered species and virtually extinct.

The discovery on Gribshunden is unique in both the Scandinavian and European contexts -such well preserved and old sturgeon remains have only been discovered a few times at an underwater archaeological site.

It is now possible, in a very specific way, to link the sturgeon to a royal environment - the discovery confirms the high status it had at the time. The fish was coveted for its roe, flesh and swim bladder - the latter could be used to produce a kind of glue (isinglass) that, among other things, was used to produce gold paint.

"The sturgeon in the King's pantry was a propaganda tool, as was the entire ship. Everything on that ship served a political function, which is another element that makes this discovery particularly interesting. It provides us with important information about this pivotal moment for nation-building in Europe, as politics, religion and economics - indeed, everything - was changing", says Brendan P. Foley, marine archaeologist at Lund University, and project coordinator for the excavations.

Gribshunden will become the subject of further archaeological excavations and scientific analyses in the coming years.