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On this day ten years ago…
via Archaeologists Find Early Known Domestic Horses: Harnessed and Milked

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BBC.com
By Paul Rincon Science editor, BBC News website

Neolithic times

Scientists have discovered the earliest direct evidence of milk consumption by humans.

The team identified milk protein entombed in calcified dental plaque (calculus) on the teeth of prehistoric farmers from Britain.

It shows that humans were consuming dairy products as early as 6,000 years ago – despite being lactose intolerant.

This could suggest they processed the raw milk into cheese, yoghurt or some other fermented product.

This would have reduced its lactose content, making it more palatable.

The team members scraped samples of plaque off the teeth, separated the different components within it and analysed them using mass spectrometry.

They detected a milk protein called beta-lactoglobulin (BLG) in the tartar of seven individuals spanning early to middle Neolithic times.

“Proteomic analysis of calculus is a fairly recent technique. There have been a few studies before, but they have generally been on historical archaeological material rather than prehistoric material,” co-author Dr Sophy Charlton, from the department of archaeology at the University of York, told BBC News.

Lactose intolerance arises from the inability to digest the lactose sugar contained in milk beyond infancy. This means that consuming milk-based foods can cause uncomfortable symptoms such as abdominal pain, diarrhoea and nausea. However, many modern Europeans possess a genetic mutation which allows for the continued consumption of milk into adulthood.

This mutation affects a section of DNA controlling the activity of the gene for lactase – an enzyme that breaks down lactose sugar. However, previous studies of the genetics of Neolithic Europeans show that they lacked this mutation.

Dr Charlton said it was possible these Stone Age people were limiting themselves to small amounts of milk. “If you are lactose intolerant and you consume very, very small amounts of milk, then it doesn’t make you too ill. You can just about cope with that,” she explained.

But Dr Charlton added: “The alternative option, which I think is perhaps slightly more plausible, is that they were processing the milk in such a way that it’s removing a degree of the lactose. So if you process it into a cheese, or a fermented milk product, or a yoghurt, then it does decrease the lactose content so you could more easily digest it.

“That idea fits quite well with other archaeological evidence for the period in which we find dairy fats inside lots of Neolithic pottery, both in the UK and the rest of Europe.”

In addition, some of the milk residues found in these pots appear to have been heated, which would be required for processing raw milk into cheese or some other product.

The human remains tested in the study come from three Neolithic sites: Hambledon Hill in Dorset, Hazleton North in Gloucestershire, and Banbury Lane in Northamptonshire.

More than one quarter of the pottery fragments at Hambledon Hill had milk lipids on them, suggesting that dairy foods were very important to the people living at that site. Other Neolithic sites show evidence of animal herds that are consistent with those used for dairying.

Genetic studies of ancient populations from across Eurasia show that lactase persistence only became common very recently, despite the consumption of milk products in the Neolithic. The mutation had started to appear by the Bronze Age, but even at this time, it was only present in 5-10% of Europeans.

The Neolithic age in Britain lasted from about 6,000 to 4,400 years ago and saw the introduction of farming, including the use of domesticated animals such as cows, sheep, pigs and goats.

The study has been published in the journal Archaeological and Anthropological Sciences.

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Donkey milk was hailed by the ancients as an elixir of long life, a cure-all for a variety of ailments, and a powerful tonic capable of rejuvenating the skin. Cleopatra, Queen of Ancient Egypt, reportedly bathed in donkey milk every day to preserve her beauty and youthful looks, while ancient Greek physician Hippocrates wrote of its incredible medicinal properties. Now it seems that interest in donkey milk is experiencing a renewed interest after Pope Francis reported thriving on it as a baby, and remarkable results are being reported in people with psoriasis, eczema, and asthma.

Donkey milk preserves beauty and youth? Legend has it that Cleopatra (60 – 39 BC), the last active Pharaoh of Egypt, insisted on a daily bath in the milk of a donkey (ass) to preserve the beauty and youth of her skin and that 700 asses were need to provide the quantity needed. It was believed that donkey milk renders the skin more delicate, preserves its whiteness, and erases facial wrinkles. According to ancient historian Pliny the Elder, Poppaea Sabina (30 – 65 AD), the wife of Roman Emperor Nero, was also an advocate of ass milk and would have whole troops of donkeys accompany her on journeys so that she too could bathe in the milk. Napoleon’s sister, Pauline Bonaparte (1780–1825 AD), was also reported to have used ass milk for her skin’s health care.

Greek physician Hippocrates (460 – 370 BC) was the first to write of the medicinal virtues of donkey milk, and prescribed it as a cure a diverse range of ailments, including liver problems, infectious diseases, fevers, nose bleeds, poisoning, joint pains, and wounds.

Roman historian Pliny the Elder (23 – 79 AD) also wrote extensively about its health benefits. In his encyclopedic work Naturalis Historia, volume 28, dealing with remedies derived from animals, Pliny added fatigue, eye stains, weakened teeth, face wrinkles, ulcerations, asthma and certain gynecological troubles to the list of afflictions it could treat:

Asses’ milk, in cases where gypsum, white-lead, sulphur, or quick-silver, have been taken internally. This last is good too for constipation attendant upon fever, and is remarkably useful as a gargle for ulcerations of the throat. It is taken, also, internally, by patients suffering from atrophy, for the purpose of recruiting their exhausted strength; as also in cases of fever unattended with head-ache. The ancients held it as one of their grand secrets, to administer to children, before taking food, a semisextarius of asses’ milk.

Over the centuries, donkey’s milk continued to be recognized for its medicinal properties. In the 1800s, donkeys were used at a hospital for assisted children in Paris to aid in the recovery of children with congenital or contagious diseases. The Popular Science Monthly, Volume 22, writes:

The infants were at first fed with goat’s milk, but it was soon found that ass’s milk was better for them; and they are now all fed with milk which they draw directly from the teat of the animal. One, two, and sometimes three children are presented to the ass at the same time, being held at the teat in the arms of the nurse, and the operation is performed with wonderful ease. Numbers speak most eloquently of the success of the method. During six months, eighty-six children afflicted with congenital and contagious diseases were fed at the nursery. The first six were fed, by stress of particular circumstances, with cow’s milk from the bottle; only one of them recovered. Forty-two were nursed at the teat of the goat; eight recovered, thirty-four died. Thirty-eight were nursed at the teat of the ass; twenty-eight recovered, ten died. In the face of such results there can be hardly any hesitation in declaring that in hospitals, at least, the best method of feeding new-born children, who cannot, for any reason, be confided to a nurse, is to put them to suck directly from the teat of an ass.

Donkey milk is the closest known milk to human breast milk with high lactose ratios and low fat content. It is also rich in vitamins, contains anti-bacterial agents, reported to be 200 times more active than in cow’s milk, and anti-allergens, which are believed to be responsible for alleviating psoriasis, eczema, asthma, and bronchitis, according to a new report in the MailOnline. “Like humans, donkeys have a single stomach,” writes the MailOnline. “Yet we mostly drink the milk of multi-stomached animals such as cows and goats, which use a lot of bacteria to digest their food through a complicated fermentation process.”

Donkey milk is still used throughout the world for its many health benefits. Source: BigStockPhoto With all these benefits, one may wonder why it is not more readily available. The answer lies in its production. A female donkey produces an average of 0.3 litres of milk a day (maximum 1 litre) for only half of the year, while cows are forced to deliver 30 times as much throughout the year. Furthermore, a donkey “won’t produce milk unless it’s stimulated by the presence of its foal, and milking has to be done manually,” writes the MailOnline. As a result, the milk sells for an extremely high price, €24 (approx. $30) a litre in Cyprus, and in other European countries the price is even double. Nevertheless, donkey milk remains fairly popular in South America, where it can be readily found at street markets.

AP reports that fresh donkey milk is sold on the streets of Chile. “Ricardo Alegria is a different sort of milk man,” writes AP. “For a quarter century or more, he and his brother Marco have led donkeys through the streets of Chile’s capital, milking them on the spot for customers.” Ricardo Alegria said the milk taken as a “vitamin jolt” for babies with stomach problems, but that adults often drink it too. While many may be put off by the price of this precious milk, a donkey seller from Golden Donkeys Farm in the village of Skarinou, Cyprus, told MailOnline that 60ml a day is “all you need to protect your body”.

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Original article:
worldtruth.tv

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Finland’s love of milk has been traced back to 2500 BC, thanks to high-tech techniques to analyze residues preserved in fragments of ancient pots.

Prehistoric dairy farming at the extremes

The Finns are the world’s biggest milk drinkers today but experts had previously been unable to establish whether prehistoric dairy farming was possible in the harsh environment that far north, where there is snow for up to four months a year.

Research by the Universities of Bristol and Helsinki, published July 30 in Proceedings of the Royal Society B, is the first of its kind to identify that dairying took place at this latitude — 60 degrees north of the equator.

This is equally as far north as Canada’s Northwestern territories, Anchorage in Alaska, Southern Greenland and near Yakutsk in Siberia.

Researchers used a series of techniques, not just to analyse the ancient pots, but also to look at modern-day Finnish peoples’ ability to digest milk into adulthood.

By comparing the residues found in the walls of cooking pots from two separate eras and cultures, dating to circa 3900 BC to 3300 BC and circa 2500 BC, it was evident that the more recent pottery fragments showed evidence of milk fats.

This coincided with the transition from a culture of hunting and fishing — relying mainly on marine foods — to the arrival of ‘Corded Ware’ settlements which we now know saw the introduction of animal domestication.

Lead author Dr Lucy Cramp, from the Department of Archaeology and Anthropology at Bristol University, said: “This is remarkable evidence which proves that four and a half thousand years ago, Stone Age people must have been foddering and sheltering domesticated animals over harsh winters, in conditions that even nowadays we would find challenging.”

The results also drew a connection between the ‘Corded Ware’ farming settlers — who were likely to have been genetically different to the hunting and fishing communities — and modern day Finns.

Fellow researcher Dr Volker Heyd added: “Our results show a clear link between an incoming pre-historic population, milk drinking and the ability to digest milk in adulthood still visible in the genetic distribution of modern Finland, which remains one of the highest consumers of dairy products in the world.”

Professor Richard Evershed, from the School of Chemistry said: “It never ceases to amaze me that these sensitive chemical signatures of changing human life survive in the archaeological record for thousands of years. And it leaves one pondering what was motivating the people to move into these challenging regions?”

Original article:
sciencedaily

Lucy J E Cramp, Richard P Evershed, Mika Lavento, Petri Halinen, Kristiina Mannermaa, Markku Oinonen, Johannes Kettunen, Markus Perola, Päivi Onkamo and Volker Heyd. Neolithic dairy farming at the extreme of agriculture in northern Europe. Proceedings of the Royal Society B, July 30, 2014;

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Corded Ware sherds.
Credit: Finnish National Board of Antiquities

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A cattle herder drives his animals in Tanzania. The study linked the spread of pastoralism with the ability to digest milk.

Credit: University of Pennsylvania

Topic: Milk
A new study led by University of Pennsylvania researchers — constituting the largest examination ever of lactase persistence in geographically diverse populations of Africans — investigated the genetic origins of this trait and offers support to the idea that the ability to digest milk was a powerful selective force in a variety of African populations which raised cattle and consumed the animals’ fresh milk.

The research was led by Alessia Ranciaro, a postdoctoral fellow in Penn’s Department of Genetics in the Perelman School of Medicine, and Sarah Tishkoff, a Penn Integrates Knowledge Professor with appointments in Penn Medicine’s Department of Genetics and Penn Arts and Sciences’ Department of Biology.

The paper will be published March 13 in the American Journal of Human Genetics.

Previous research had shown that northern Europeans and people with northern European ancestry, as well as populations from Africa, the Arabian Peninsula and Central Asia with a tradition of fresh milk production and consumption, continue to express the lactase enzyme into adulthood. Some of these earlier studies had traced the genetic origin of this trait in Europeans to a particular mutation that regulates the expression of the gene that codes for lactase. And in 2007 a study by Tishkoff, Ranciaro and colleagues examined African populations and found three addition genetic variants associated with lactase persistence that had not been previously identified.

“But these variants didn’t completely account for the reason why some Africans were able to digest milk,” Ranciaro said.

To try to reconcile these apparent discrepancies between genotype, the genetic basis of a characteristic, and phenotype, the characteristic itself, Ranciaro, along with colleagues, led field studies to often-remote areas of Kenya, Tanzania and Sudan to collect blood samples and perform a lactose tolerance test on people from diverse ethnic backgrounds.

“The idea was that we wanted to sample as many populations, and as diverse a set of populations, as possible,” Ranciaro said. “We included pastoralists, agro-pastoralists, agriculturalists and hunter-gatherers, so the four major subsistence patterns were all covered.”

The Penn researchers worked with African collaborators and local district offices and tribal chiefs to spread the word and recruit volunteers for their study.

“This was a very challenging test to do in the field in remote regions,” said Ranciaro. “We were careful to make sure that people understood why we were doing this study and that they would need to commit to the hour or more of time needed to do the test.”

The test reveals whether someone has the ability to digest lactose into glucose and galactose. It requires participants to fast overnight, have their blood sugar measured, then drink a sweet beverage containing the equivalent lactose of one to two liters of cow’s milk and subsequently have their blood sugar tested at set intervals.

To look for genetic variations among the populations’ abilities to digest milk, the team sequenced three genomic regions thought to influence the activity of the lactase-encoding LCT gene in 819 Africans from 63 different populations and 154 non-Africans from nine different populations in Europe, the Middle East and Central and East Asia. They also examined the results of the lactose tolerance test in 513 people from 50 populations in East Africa.

Their sequencing and phenotyping efforts confirmed the association between lactase persistence and three known single-nucleotide polymorphisms, or SNPs, places where the DNA sequence varies in just one “letter.” But they also identified two new SNPs associated with the trait located in regions that are thought to regulate lactase gene expression.

Their analysis revealed strong evidence of recent positive selection affecting several variants associated with lactase persistence in African populations, likely in response to the cultural development of pastoralism. The distinct geographic patterns in which these variants were present correlate in many cases with historic human migrations, mixing between populations as well as the spread of cattle, camels or sheep.

For example, they found the variant associated with lactase persistence in Europeans, T-13910, in central and northern African pastoralist groups, suggesting that these groups may have mixed historically with a non-African population. The age of this genetic mutation is estimated to be 5,000-12,300 years old, coinciding with the origins of cattle domestication in North Africa and the Middle East. And a variant, G-13915, found at high frequencies in the Arabian Peninsula, and also present in northern Kenya and northern Sudan, dates to roughly 5,000 years ago, around the time that archaeological evidence suggests that camels were domesticated in the region.

Another variant, G-13907, was identified in the northern reaches of Sudan and Kenya as well as in Ethiopia. The researchers speculate that the mutation may have arisen in Cushitic populations in Ethiopia, who later migrated into Kenya and Sudan in the last 5,000 years.

They observed still another variant, C-14010, in Tanzania and Kenya as well as in southern Africa. This variant is believed to have arisen 3,000 to 7,000 years ago, a timing in line with the migration of pastoralists from North Africa into East Africa. The researchers’ analysis suggests that this variant spread more recently into southern African, perhaps only in the last 1,000 years.

“We’re starting to paint a picture of convergent evolution,” Tishkoff said. “Our results are showing different mutations arising in different places that are under selection and rising to high frequencies and then reintroduced by migration to new areas and new populations.”

Even with the new variants the Penn team identified, there were still patterns that the genetic data couldn’t explain. Some groups that appeared to be able to digest milk lacked any genetic sign of this ability. The Hadza, nearly half of whom had the lactase persistence trait, are one example.

“This raises the strong possibility that there are other variants out there, perhaps in regions of the genome we haven’t yet examined,” Tishkoff said.

Another possibility is that commensal bacteria in the gut could offer humans a helping hand in digesting milk. The team is now assaying Africans’ gut bacteria to see if that might be the case.

Additional co-authors on the study included Michael C. Campbell, Jibril B. Hirbo and Wen-Ya Ko of Penn’s Department of Genetics; Alain Froment of the Musée de l’Homme in Paris; Paolo Anagnostou of Universita’ La Sapienza and Istituto Italiano di Antropologia in Rome; Maritha J. Kotze of the University of Stellenbosch in South Africa; Muntaser Ibrahim of the University of Khartoum; Thomas Nyambo of Muhimbili University of Health and Allied Sciences in Tanzania; and Sabah A. Omar of the Kenya Medical Research Institute.

Original article:
sciencedaily
March 13, 2014

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Topic Ancient milk drinkers:

The mutation for milk-drinking evolved independently in different parts of the world over the last 10,000 years as a result of strong natural selection, but why was it so advantageous?

Among the more momentous developments in human evolution was the ability to digest milk beyond early childhood.

Mutations that enabled lifelong milk drinking appeared independently in several parts of the world over the last 7,500 years, according to growing evidence. And those genes spread rapidly. Today, about a third of adults around the world can drink milk without stomach problems, a trait known as lactase persistence.
But why was milk drinking so advantageous to humankind?

A new study debunks one leading theory: that milk provided a valuable source of vitamin D, which would’ve helped people absorb its calcium.

Newly analyzed human skeletons from an ancient site in Spain show that the milk-drinking gene spread just as rapidly in that sun-drenched climate as it did in other places, suggesting that milk must have been beneficial there for some reason other than its vitamin D content.

“Throughout the years, I have heard so many evolutionary hypotheses about lactase persistence because they are so fun to coin,” said Oddný Sverrisdóttir, an evolutionary biologist at the University of Uppsala in Sweden. “For decades now, people have hypothesized that it was because of lack of sunlight in the north of Europe that people would have had to supplement the lack of calcium and vitamin D by drinking milk.”

“Now, looking at this picture from Spain,” she said, “the calcium-assimilation hypothesis either didn’t affect the evolution of lactase persistence at all, or other forces were there as well.”

Sverrisdóttir has long been interested in how and why Europe’s early farmers began drinking milk, so she was excited when she got her hands on well-preserved samples of skeletal remains from eight people who lived in northeastern Spain about 5,000 years ago. That was well after the milk-drinking mutation had appeared in northern Europe, and she was eager to find out if those ancient Spaniards were drinking milk, too. So the first thing she did was test their DNA for lactase persistence.

“I thought at least one would have the mutation,” since so many of today’s Spanish adults can drink milk without health consequences, Sverrisdóttir said. “None did.”

To figure out whether the recent and rapid spread of lactase persistence in Spain was a fluke or if natural selection was at play, Sverrisdóttir and colleagues compared the mitochondrial DNA of modern Spaniards with the ancient samples. Mitochondrial DNA changes very slowly, making it ideal for tracing family trees over time.

And, the researchers report today in the journal Molecular Biology and Evolution, analyses showed that the ancient cave dwellers were indeed ancestors of people who live and frequently drink milk in Spain today.

Original article:

discovery.com

JAN 21, 2014 08:00 PM ET // BY EMILY SOHN

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Topic: Milk for the ages

When a single genetic mutation first let ancient Europeans drink milk, it set the stage for a continental upheaval.

In the 1970s, archaeologist Peter Bogucki was excavating a Stone Age site in the fertile plains of central Poland when he came across an assortment of odd artefacts. The people who had lived there around 7,000 years ago were among central Europe’s first farmers, and they had left behind fragments of pottery dotted with tiny holes. It looked as though the coarse red clay had been baked while pierced with pieces of straw.

Looking back through the archaeological literature, Bogucki found other examples of ancient perforated pottery. “They were so unusual — people would almost always include them in publications,” says Bogucki, now at Princeton University in New Jersey. He had seen something similar at a friend’s house that was used for straining cheese, so he speculated that the pottery might be connected with cheese-making. But he had no way to test his idea.

The mystery potsherds sat in storage until 2011, when Mélanie Roffet-Salque pulled them out and analysed fatty residues preserved in the clay. Roffet-Salque, a geochemist at the University of Bristol, UK, found signatures of abundant milk fats — evidence that the early farmers had used the pottery as sieves to separate fatty milk solids from liquid whey. That makes the Polish relics the oldest known evidence of cheese-making in the world.

Roffet-Salque’s sleuthing is part of a wave of discoveries about the history of milk in Europe. Many of them have come from a €3.3-million (US$4.4-million) project that started in 2009 and has involved archaeologists, chemists and geneticists. The findings from this group illuminate the profound ways that dairy products have shaped human settlement on the continent.

During the most recent ice age, milk was essentially a toxin to adults because — unlike children — they could not produce the lactase enzyme required to break down lactose, the main sugar in milk. But as farming started to replace hunting and gathering in the Middle East around 11,000 years ago, cattle herders learned how to reduce lactose in dairy products to tolerable levels by fermenting milk to make cheese or yogurt. Several thousand years later, a genetic mutation spread through Europe that gave people the ability to produce lactase — and drink milk — throughout their lives. That adaptation opened up a rich new source of nutrition that could have sustained communities when harvests failed.

This two-step milk revolution may have been a prime factor in allowing bands of farmers and herders from the south to sweep through Europe and displace the hunter-gatherer cultures that had lived there for millennia. “They spread really rapidly into northern Europe from an archaeological point of view,” says Mark Thomas, a population geneticist at University College London. That wave of emigration left an enduring imprint on Europe, where, unlike in many regions of the world, most people can now tolerate milk. “It could be that a large proportion of Europeans are descended from the first lactase-persistent dairy farmers in Europe,” says Thomas.

Strong stomachs

Young children almost universally produce lactase and can digest the lactose in their mother’s milk. But as they mature, most switch off the lactase gene. Only 35% of the human population can digest lactose beyond the age of about seven or eight (ref. 2). “If you’re lactose intolerant and you drink half a pint of milk, you’re going to be really ill. Explosive diarrhoea — dysentery essentially,” says Oliver Craig, an archaeologist at the University of York, UK. “I’m not saying it’s lethal, but it’s quite unpleasant.”

Most people who retain the ability to digest milk can trace their ancestry to Europe, where the trait seems to be linked to a single nucleotide in which the DNA base cytosine changed to thymine in a genomic region not far from the lactase gene. There are other pockets of lactase persistence in West Africa (see Nature 444, 994–996; 2006), the Middle East and south Asia that seem to be linked to separate mutations (see ‘Lactase hotspots’).

The single-nucleotide switch in Europe happened relatively recently. Thomas and his colleagues estimated the timing by looking at genetic variations in modern populations and running computer simulations of how the related genetic mutation might have spread through ancient populations. They proposed that the trait of lactase persistence, dubbed the LP allele, emerged about 7,500 years ago in the broad, fertile plains of Hungary.

Powerful gene

Once the LP allele appeared, it offered a major selective advantage. In a 2004 study, researchers estimated that people with the mutation would have produced up to 19% more fertile offspring than those who lacked it. The researchers called that degree of selection “among the strongest yet seen for any gene in the genome”.

Compounded over several hundred generations, that advantage could help a population to take over a continent. But only if “the population has a supply of fresh milk and is dairying”, says Thomas. “It’s gene–culture co-evolution. They feed off of each other.”

To investigate the history of that interaction, Thomas teamed up with Joachim Burger, a palaeogeneticist at the Johannes Gutenberg University of Mainz in Germany, and Matthew Collins, a bioarchaeologist at the University of York. They organized a multidisciplinary project called LeCHE (Lactase Persistence in the early Cultural History of Europe), which brought together a dozen early-career researchers from around Europe.

By studying human molecular biology and the archaeology and chemistry of ancient pottery, LeCHE participants also hoped to address a key issue about the origins of modern Europeans. “It’s been an enduring question in archaeology — whether we’re descended from Middle Eastern farmers or indigenous hunter-gatherers,” says Thomas. The argument boils down to evolution versus replacement. Did native populations of hunter-gatherers in Europe take up farming and herding? Or was there an influx of agricultural colonists who outcompeted the locals, thanks to a combination of genes and technology?

One strand of evidence came from studies of animal bones found at archaeological sites. If cattle are raised primarily for dairying, calves are generally slaughtered before their first birthday so that their mothers can be milked. But cattle raised mainly for meat are killed later, when they have reached their full size. (The pattern, if not the ages, is similar for sheep and goats, which were part of the dairying revolution.)

On the basis of studies of growth patterns in bones, LeCHE participant Jean-Denis Vigne, an archaeozoologist at the French National Museum of Natural History in Paris, suggests that dairying in the Middle East may go all the way back to when humans first started domesticating animals there, about 10,500 years ago. That would place it just after the Middle Eastern Neolithic transition — when an economy based on hunter-gathering gave way to one devoted to agriculture. Dairying, says Roz Gillis, also an archaeozoologist at the Paris museum, “may have been one of the reasons why human populations began trapping and keeping ruminants such as cattle, sheep and goats”. (See ‘Dairy diaspora’.)

Dairying then expanded in concert with the Neolithic transition, says Gillis, who has looked at bone growth at 150 sites in Europe and Anatolia (modern Turkey). As agriculture spread from Anatolia to northern Europe over roughly two millennia, dairying followed a similar pattern.

On their own, the growth patterns do not say whether the Neolithic transition in Europe happened through evolution or replacement, but cattle bones offer important clues. In a precursor study, Burger and several other LeCHE participants found that domesticated cattle at Neolithic sites in Europe were most closely related to cows from the Middle East, rather than indigenous wild aurochs. This is a strong indication that incoming herders brought their cattle with them, rather than domesticating locally, says Burger. A similar story is emerging from studies of ancient human DNA recovered at a few sites in central Europe, which suggest that Neolithic farmers were not descended from the hunter-gatherers who lived there before.

Taken together, the data help to resolve the origins of the first European farmers. “For a long time, the mainstream of continental European archaeology said Mesolithic hunter-gatherers developed into Neolithic farmers,” says Burger. “We basically showed they were completely different.”

Milk or meat

Given that dairying in the Middle East started thousands of years before the LP allele emerged in Europe, ancient herders must have found ways to reduce lactose concentrations in milk. It seems likely that they did so by making cheese or yogurt. (Fermented cheeses such as feta and cheddar have a small fraction of the lactose found in fresh milk; aged hard cheeses similar to Parmesan have hardly any.)

To test that theory, LeCHE researchers ran chemical tests on ancient pottery. The coarse, porous clay contains enough residues for chemists to distinguish what type of fat was absorbed during the cooking process: whether it was from meat or milk, and from ruminants such as cows, sheep and goats or from other animals. “That gave us a way into saying what types of things were being cooked,” says Richard Evershed, a chemist at the University of Bristol.

Evershed and his LeCHE collaborators found milk fat on pottery in the Middle Eastern Fertile Crescent going back at least 8,500 years, and Roffet-Salque’s work on the Polish pottery offers clear evidence that herders in Europe were producing cheese to supplement their diets between 6,800 and 7,400 years ago. By then, dairy had become a component of the Neolithic diet, but it was not yet a dominant part of the economy.

That next step happened slowly, and it seems to have required the spread of lactase persistence. The LP allele did not become common in the population until some time after it first emerged: Burger has looked for the mutation in samples of ancient human DNA and has found it only as far back as 6,500 years ago in northern Germany.

Models created by LeCHE participant Pascale Gerbault, a population geneticist at University College London, explain how the trait might have spread. As Middle Eastern Neolithic cultures moved into Europe, their farming and herding technologies helped them to out-compete the local hunter-gatherers. And as the southerners pushed north, says Gerbault, the LP allele ‘surfed’ the wave of migration.

Lactase persistence had a harder time becoming established in parts of southern Europe, because Neolithic farmers had settled there before the mutation appeared. But as the agricultural society expanded northwards and westwards into new territory, the advantage provided by lactase persistence had a big impact. “As the population grows quickly at the edge of the wave, the allele can increase in frequency,” says Gerbault.

The remnants of that pattern are still visible today. In southern Europe, lactase persistence is relatively rare — less than 40% in Greece and Turkey. In Britain and Scandinavia, by contrast, more than 90% of adults can digest milk.

Cattle conquest

By the late Neolithic and early Bronze Age, around 5,000 years ago, the LP allele was prevalent across most of northern and central Europe, and cattle herding had become a dominant part of the culture. “They discover this way of life, and once they can really get the nutritional benefits they increase or intensify herding as well,” says Burger. Cattle bones represent more than two-thirds of the animal bones in many late Neolithic and early Bronze Age archaeological sites in central and northern Europe.

The LeCHE researchers are still puzzling out exactly why the ability to consume milk offered such an advantage in these regions. Thomas suggests that, as people moved north, milk would have been a hedge against famine. Dairy products — which could be stored for longer in colder climes — provided rich sources of calories that were independent of growing seasons or bad harvests.

Others think that milk may have helped, particularly in the north, because of its relatively high concentration of vitamin D, a nutrient that can help to ward off diseases such as rickets. Humans synthesize vitamin D naturally only when exposed to the sun, which makes it difficult for northerners to make enough during winter months. But lactase persistence also took root in sunny Spain, casting vitamin D’s role into doubt.

The LeCHE project may offer a model for how archaeological questions can be answered using a variety of disciplines and tools. “They have got a lot of different tentacles — archaeology, palaeoanthropology, ancient DNA and modern DNA, chemical analysis — all focused on one single question,” says Ian Barnes, a palaeogeneticist at Royal Holloway, University of London, who is not involved in the project. “There are lots of other dietary changes which could be studied in this way.”

The approach could, for example, help to tease apart the origins of amylase, an enzyme that helps to break down starch. Researchers have suggested that the development of the enzyme may have followed — or made possible — the increasing appetite for grain that accompanied the growth of agriculture. Scientists also want to trace the evolution of alcohol dehydrogenase, which is crucial to the breakdown of alcohol and could reveal the origins of humanity’s thirst for drink.

Some of the LeCHE participants are now probing further back in time, as part of a project named BEAN (Bridging the European and Anatolian Neolithic), which is looking at how the first farmers and herders made their way into Europe. Burger, Thomas and their BEAN collaborators will be in Turkey this summer, tracing the origins of the Neolithic using computer models and ancient-DNA analysis in the hope of better understanding who the early farmers were, and when they arrived in Europe.

Along the way, they will encounter beyaz peynir, a salty sheep’s-milk cheese eaten with nearly every Turkish breakfast. It is probably much like the cheese that Neolithic farmers in the region would have eaten some 8,000 years ago — long before the march of lactase persistence allowed people to drink fresh milk.

Original article:
nature.com
By Andrew Curry July 16, 2013

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