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Original Article:

Independent
By Ian Johnston, July3,2017

potato’ dating back about 10,900 years have been discovered in Utah.
The “well-preserved starch granules” – discovered in cracks in rocks used to grind up the potatoes – are the oldest evidence of cultivation of the plant in North America, researchers said.
This technique has been used to find the earliest known use of several species, including oats found in southern Italy dating to 32,600 years ago, 23,000-year-old barley and wheat discovered in Israel, and beans and yams from China dated to between 19,500 and 23,000 years ago.
The potato starch was embedded into stone tools found in Escalante, Utah, an area once known to early European settlers as “Potato Valley”.
The ‘Four Corners’ potatoes, Solanum jamesii, were eaten by several Native American tribes, including the Apache, Navajo and Hopi.
However most potatoes eaten around the world today are all descended from one species, Solanum tuberosum, which was domesticated in the South American Andes more than 7,000 years ago. It has been bred into thousands of different types since then.
The Four Corners potato, which may be the first example of a domesticated plant in the American West, could be used to make the current potato crop more resilient to drought and disease, it is believed.
Professor Lisbeth Louderback, an archaeologist at the Natural History Museum of Utah and a senior author of a paper published in the journal Proceedings of the National Academy of Sciences, said: “This potato could be just as important as those we eat today, not only in terms of a food plant from the past, but as a potential food source for the future.
“The potato has become a forgotten part of Escalante’s history. Our work is to help rediscover this heritage.”
S. jamesii is also highly nutritious with twice the amount of protein, zinc and manganese and three times the calcium and iron content as S. tuberosum.
Grown in ideal conditions in a greenhouse, a single “mother” tuber can produce 125 progeny tubers in six months.
Early European visitors to the Escalante area remarked on the potatoes.
Captain James Andrus wrote in August 1866: “We have found wild potatoes growing from which the valley takes its name.”
And a soldier, John Adams, wrote in the same year: “We gathered some wild potatoes which we cooked and ate … they were somewhat like the cultivated potato, but smaller.”

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Original article:

Sciencedaily
Studying dental plaque from a 1.2 million year old hominin (early human species), recovered by the Atapuerca Research Team in 2007 in Sima del Elefante in northern Spain, archaeologists extracted microfossils to find the earliest direct evidence of food eaten by early humans.
These microfossils included traces of raw animal tissue, uncooked starch granules indicating consumption of grasses, pollen grains from a species of pine, insect fragments and a possible fragment of a toothpick.
All detected fibres were uncharred, and there was also no evidence showing inhalation of microcharcoal – normally a clear indicator of proximity to fire.
The timing of the earliest use of fire for cooking is hotly contested, with some researchers arguing habitual use started around 1.8 million years ago while others suggest it was as late as 300,000-400,000 years ago.
Possible evidence for fire has been found at some very early sites in Africa. However, the lack of evidence for fire at Sima del Elefante suggests that this knowledge was not carried with the earliest humans when they left Africa.
The earliest definitive evidence in Europe for use of fire is 800,000 years ago at the Spanish site of Cueva Negra, and at Gesher Benot Ya’aqov, Israel, a short time later.
Taken together, this evidence suggests the development of fire technology occurred at some point between 800,000 and 1.2 million years ago, revealing a new timeline for when the earliest humans started to cook food.
Dr Karen Hardy, lead author and Honorary Research Associate at the University of York and ICREA Research Professor at the Universitat Autònoma de Barcelona, said: “Obtaining evidence for any aspect of hominin life at this extremely early date is very challenging. Here, we have been able to demonstrate that these earliest Europeans understood and exploited their forested environment to obtain a balanced diet 1.2 million years ago, by eating a range of different foods and combining starchy plant food with meat.
“This new timeline has significant implications in helping us to understand this period of human evolution — cooked food provides greater energy, and cooking may be linked to the rapid increases in brain size that occurred from 800,000 years ago onwards.
“It also correlates well with previous research hypothesising that the timing of cooking is linked to the development of salivary amylase, needed to process cooked starchy food. Starchy food was an essential element in facilitating brain development, and contrary to popular belief about the ‘Paleodiet’, the role of starchy food in the Palaeolithic diet was significant.”
Dr Anita Radini, PhD student at the University of York said: “These results are very exciting, as they highlight the potential of dental calculus to store dietary and environmental information from deep in the human evolutionary past. It is also interesting to see that pollen remains are preserved often in better conditions than in the soil of the same age. Overall this is a very positive step in the discipline, in terms of preservation of material in the calculus matrix.”

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A statue representing "iceman" mummy Oetzi, discovered on 1991 in the Italian Schnal Valley glacier, displayed at the Archaeological Museum of Bolzano, Italy on February 28, 2011

A statue representing “iceman” mummy Oetzi, discovered on 1991 in the Italian Schnal Valley glacier, displayed at the Archaeological Museum of Bolzano, Italy on February 28, 2011

Original Article:

phys.org

 

Oetzi the famous “iceman” mummy of the Alps appears to have enjoyed a fine slice or two of Stone Age bacon before he was killed by an arrow some 5,300 years ago.

His last meal was most likely dried goat meat, according to scientists who recently managed to dissect the contents of Oetzi’s stomach.

“We’ve analysed the meat’s nanostructure and it looks like he ate very fatty, dried meat, most likely bacon,” German mummy expert Albert Zink said at a talk in Vienna late Wednesday.

More specifically, the tasty snack is thought to have come from a wild goat in South Tyrol, the northern Italian region where Oetzi roamed around and where his remains were found in September 1991.

Mummified in ice, he was discovered by two German hikers in the Oetztal Alps, 3,210 metres (10,500 feet) above sea level.

Scientists have used hi-tech, non-invasive diagnostics and genomic sequencing to penetrate his mysterious past.

These efforts have determined Oetzi died around the age of 45, was about 1.60 metres (five foot, three inches) tall and weighed 50 kilos (110 pounds).

He suffered a violent death, with an arrow severing a major blood vessel between the rib cage and the left shoulder blade, as well as a laceration on the hand.

As part of their latest discoveries, Zink’s team also found that Oetzi had an ulcer-inducing bacteria and may have suffered from stomach aches.

But for all his parasites, worn ligaments and bad teeth, he was in “pretty good shape”, Zink wrote in the renowned US magazine Science earlier this month.

 

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 Humans living in Argentina 14,000 years ago were hunting giant armadillos. This one looks especially grumpy.

Humans living in Argentina 14,000 years ago were hunting giant armadillos. This one looks especially grumpy.

 

Original Article:

By ANNALEE NEWITZ

arstechnica.com

 

A glimpse of the last people on Earth to colonize a continent without humans.

 

For more than a decade, evidence has been piling up that humans colonized the Americas thousands of years before the Clovis people. The Clovis, who are the early ancestors of today’s Native Americans, left abundant evidence of their lives behind in the form of tools and graves. But the mysterious pre-Clovis humans, who likely arrived 17,000 to 15,000 years ago, have left only a few dozen sources of evidence for their existence across the Americas, mostly at campsites where they processed animals during hunting trips. Now a fresh examination of one such campsite, a 14,000-year-old hunter’s rest stop outside the city of Tres Arroyos in Argentina, has given us a new understanding of how the pre-Clovis people might have lived.

Archaeologists are still uncertain how the pre-Clovis people arrived in the Americas. They came after the end of the ice age but at a time when glaciers and an icy, barren environment would still have blocked easy entrance into the Americas via Northern Canada. So it’s extremely unlikely that they marched over a land bridge from Siberia and into the Americas through the middle of the continent—instead, they would have come from Asia via a coastal route, frequently using boats for transport. That would explain why many pre-Clovis sites are on the coast, on islands, or on rivers that meet the ocean.
These early settlers were hunter-gatherers who used stone tools for a wide range of activities, including hunting, butchery, scraping hides, preparing food, and making other tools out of bone and wood. Many of the pre-Clovis stone tools look fairly simple and were made by using one stone to flake pieces off the other, thus creating sharp edges. At the campsite in Argentina, known as the Arroyo Seco 2 site, archaeologists have found more than 50 such tools made from materials like chert and quartzite. They’re scattered across an area that was once a grassy knoll above a deep lake, which is rich with thousands of animal bone fragments that have been carbon dated to as early as 14,000 years ago. There are even a couple-dozen human burials at the site, dated to a later period starting roughly 9,000 years ago. The spot has the characteristic look of a hunter’s camp, used for processing animals, that was revisited seasonally for thousands of years.

Writing in PLoS One, the researchers describe a number of reasons why a bunch of sharp-edged rocks and broken animal bones point to a 14,000-year-old human occupation of Argentina. First of all, there are far too many animal bones from a diversity of species grouped in one place for it to be accidental. Yes, there are some natural traps where we find massive numbers of prehistoric bones, but those are almost always in holes or depressions in the ground—and this area was on a rather high hill during the Pleistocene. Second, the stones aren’t just sharp-edged in a way that suggests flaking; many also show signs of wear and tear from scraping hide. “A large majority of the flaked edges were used transversely on dry skin,” the researchers write. “Consequently, it is likely that the skins were brought to the site in a state of intermediate processing.” Also, most of the stone used for the tools, including quartzite and chert, can only be found over 110km from Arroyo Seco. So that piece of evidence also points to human hunter-gatherers carrying tools with them over great distances.
The Pleistocene diet

One question remains. How can we be sure the tools at the site really are 14,000 years old? Archaeologists infer some of this from carbon dates on the animal bones, which have been tested by several labs around the world. The problem is that the site’s stratigraphy, or historical layers, are difficult to read due to erosion at the site. So even if a tool appears right next to a bone in a given layer, it may have come from later and been moved around by wind and water. That said, there is evidence that some of the early bones were broken by stone tools. A 14,000-year-old bone from Equus neogeus, an extinct American horse, bears distinct marks from a hammerstone. “This bone was intentionally broken while still fresh,” note the researchers.

With a firm connection between the human tools and the animal bones found at Arroyo Seco, we can begin to piece together what everyday life was like for these people—at least at mealtime. Analysis of more than 600 bone fragments out of thousands found at the site revealed that a large amount of these people’s meat came from animals that no longer exist. Various extinct horse species were a major part of the pre-Clovis diet, as were other extinct mammals like giant ground sloths, camels, mammoths, and giant armadillos. When these people arrived in South America, they found a land that no human had ever colonized. Many of these species would have been easy pickings for well-organized bands of hunters with sophisticated languages, tools, and tactics. Some paleoecologists hypothesize that these animals went extinct partly due to human hunting, and this campsite definitely provides evidence that extinct animals were part of the pre-Clovis diet for millennia. That said, Arroyo Seco contains far more bones from guanaco (a local relative of the camel) and rodents than it does from extinct mammals.

The absence of certain bones can tell us about how these people lived, too. Though there are bones from megafauna like the giant sloth Megatherium, we see no skulls, chest, or pelvic bones from the animal. The researchers speculate that’s because hunters would have done an initial butchery at the site where they killed or scavenged the animal and then transported parts of it to be processed at camp:

Given the body mass of this species (between 4 and 5 tons), it would have been extremely difficult to transport the entire carcass and even challenging to transport complete hindquarters weighing between 600 and 750 kg, and forequarters weighing between 250 and 300 kg. Taking into consideration these values, the best hypothesis is that the Megatherium was hunted or scavenged near the site, the skeleton was butchered into smaller parts, and these units were then transported to their current location at the site. The larger bones were transported with portions of meat already removed, and the bone may have been used for other purposes such as bone quarrying.

Of the extinct mammals that humans processed at Arroyo Seco, the most common seems to be horse. When people arrived in the Americas, it was full of at least two species of extinct horses. But by the time of the Inca and other great civilizations of South America, those animals were long gone. It wasn’t until Europeans arrived with their steeds that the continent was once again populated with horses.

Still, we can look back and imagine what it must have been like for those pre-Clovis people, entering a world where no human had ever gone before, full of animals that are legendary to us today. In many ways, they lived on a different planet than the one we inhabit now. At the edge of a now mostly vanished lake, on a knoll, those people fed their families, made tools, and strategized about how to hunt for game bigger than anything on land in the modern world. They returned year after year for centuries. Eventually, they buried their dead there among the animal bones left by their ancestors.

 

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Right: Photograph during excavation exhibiting excellent dry preservation of plant remains Left: A well-preserved, desiccated barley grain found at Yoram Cave Credit: Uri Davidovich

Right: Photograph during excavation exhibiting excellent dry preservation of plant remains Left: A well-preserved, desiccated barley grain found at Yoram Cave Credit: Uri Davidovich

 

Original Article:

popular-archaeology.com

 

BAR-ILAN UNIVERSITY—An international team of researchers has succeeded for the first time in sequencing the genome of Chalcolithic barley grains. This is the oldest plant genome to be reconstructed to date. The 6,000-year-old seeds were retrieved from Yoram Cave in the southern cliff of Masada fortress in the Judean Desert in Israel, close to the Dead Sea. Genetically, the prehistoric barley is very similar to present-day barley grown in the Southern Levant, supporting the existing hypothesis of barley domestication having occurred in the Upper Jordan Valley.

Members of the research team are from the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) in Gatersleben, Germany; Bar-Ilan University in Ramat Gan, Israel; Hebrew University, Jerusalem, Israel; the Max Planck Institute for the Science of Human History in Jena, Germany; and the University of Haifa, Israel; The James Hutton Institute, UK; University of California, Santa Cruz, USA; University of Minnesota St. Paul, USA; University of Tübingen, Germany.

The analyzed grains, together with tens of thousands of other plant remains, were retrieved during a systematic archaeological excavation headed by Uri Davidovich, from the Institute of Archaeology, The Hebrew University of Jerusalem, and Nimrod Marom, from Zinman Institute of Archaeology, University of Haifa, Israel. The archaeobotanical analysis was led by Ehud Weiss, of Bar-Ilan University. The cave is very difficult to access and was used only for a short time by humans, some 6,000 years ago, probably as ephemeral refuge.

Oldest plant genome reconstructed to date

Most examination of archaeobotanical findings has been limited to the comparison of ancient and present-day specimens based on their morphology. Up to now, only prehistoric corn has been genetically reconstructed. In this research, the team succeeded in sequencing the complete genome of the 6,000-year-old barley grains. The results are now published in the online version of the journal Nature Genetics.

“These archaeological remains provided a unique opportunity for us to finally sequence a Chalcolithic plant genome. The genetic material has been well-preserved for several millennia due to the extreme dryness of the region,” explains Ehud Weiss, of Bar-Ilan University. In order to determine the age of the ancient seeds, the researchers split the grains and subjected half of them to radiocarbon dating while the other half was used to extract the ancient DNA. “For us, ancient DNA works like a time capsule that allows us to travel back in history and look into the domestication of crop plants at distinct time points in the past,” explains Johannes Krause, Director of the Department of Archaeogenetics at the Max Planck Institute for the Science of Human History in Jena. The genome of Chalcolithic barley grains is the oldest plant genome to be reconstructed to date.

Domestication of barley completed very early

Wheat and barley were already grown 10,000 years ago in the Fertile Crescent, a sickle-shaped region stretching from present-day Iraq and Iran through Turkey and Syria into Lebanon, Jordan and Israel. Up to this day, the wild forms of these two crops persist in the region and are among the major model species studied at the Institute of Evolution in the University of Haifa. “It was from there that grain farming originated and later spread to Europe, Asia and North Africa,” explains Tzion Fahima, of the University of Haifa.

“Our analyses show that the seeds cultivated 6,000 years ago greatly differ genetically from the wild forms we find today in the region. However, they show considerable genetic overlap with present-day domesticated lines from the region,” explains Nils Stein, who directed the comparison of the ancient genome with modern genomes at the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, with the support of Robbie Waugh and colleagues at the James Hutton Institute, Dundee, Scotland, and Gary Muehlbauer, University of Minnesota, USA. “This demonstrates that the domestication of barley in the Fertile Crescent was already well advanced very early.”

The comparison of the ancient seeds with wild forms from the region and with so-called ‘landraces’ (i.e., local barley lines grown by farmers in the Near East) enabled to geographically suggest, according to Tzion Fahima and his colleagues at the University of Haifa and Israel’s Tel-Hai College, “the origin of the domestication of barley within the Upper Jordan Valley – a hypothesis that is also supported by two archaeological sites in the surrounding area where the hitherto earliest remains of barley cultivation have been found.

Immigrants “trust” in extant landraces

Also the genetic overlap with present-day domesticated lines from the region is revealing to the researchers. “This similarity is an amazing finding considering to what extent the climate, but also the local flora and fauna, as well as the agricultural methods, have changed over this long period of time,” says Martin Mascher, from the Leibniz Institute of Plant Genetics and Crop Plant Research, the lead author of the study. The researchers therefore assume that conquerors and immigrants coming to the region did not bring their own crop seeds from their former homelands, but continued cultivating the locally adapted extant landraces.

New insights into the origins of our crop plants

Combining archaeology, archaeobotany, genetics and computational genomics in an interdisciplinary study has produced novel insights into the origins of our crop plants. “This is just the beginning of a new and exciting line of research,” predicts Verena Schuenemann, from Tuebingen University, the second lead author of the study. “DNA-analysis of archaeological remains of prehistoric plants will provide us with novel insights into the origin, domestication and spread of crop plants.”

Source: Bar-Ilan University news release.

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The mammoth was found on the left bank of Yenisey river, not far from Sopochnaya Karga meterological station. Pictures: Vladimir Pitulko, Alexei Tikhonov

The mammoth was found on the left bank of Yenisey river, not far from Sopochnaya Karga meterological station. Pictures: Vladimir Pitulko, Alexei Tikhonov

inside_excavations_1

 

Original article:

siberiantimes.com

By Anna Liesowska

30 May 2016

 

When Science journal earlier this year highlighted an ancient woolly mammoth with suspected spear wounds it provoked media interest around the world. Until now, the pictures of the remarkable prehistoric ‘injuries’ were not widely seen outside academic circles.

Today The Siberian Times is publishing the images which respected Russian scientists believe is clear proof of ancient man’s attacks on a creature preserved in the permafrost.

If true, the implications are enormous. It would mean, firstly, that man was present in the frozen Arctic wastes a full 10,000 years earlier than previously understood.

Yet it would also establish that early Siberians were just 2,895 miles (4,660 kilometres) from what was then a land bridge between modern Russia and Alaska. A long distance, for sure, but far from insurmountable, opening the possibility that Stone Age Siberians colonised the Americas at this early point.

The 15-year-old male mammoth died on the eastern bank of the giant Yenisei River in northern Siberia, and its remains were found by a 11 year old schoolboy in 2012. It is known variously as the Zhenya mammoth, after the boy who found it, and the Sopkarginsky mammoth, deriving from the location where it was found.

Forensic analysis of the remains – which included still-preserved soft tissue – found evidence that the animal, now long extinct, was hunted and killed by early man using primitive weapons and tools made of bone and stone.

Dr Vladimir Pitulko, lead author of the study published in Science, told The Siberian Times: ‘Most likely the hunters threw relatively light spears. It is a usual hunting tactic, in particular in elephant hunts, which is still practiced in Africa.

‘An elephant is bombarded with a large number of light spears. Then, pierced with such ‘needles’ like a hedgehog, the animal starts losing blood. Even a light spear can penetrate quite deep and injure the vital organs.

‘The mobility of the animal is seriously limited, and then it is soon possible to finish it with a strait blow. I think that the same happened to the Sopkarginsky mammoth.’

He said: ‘The most remarkable injury is to the fifth left rib, caused by a slicing blow, inflicted from the front and somewhat from above in a downward direction. Although it was a glancing blow, it was strong enough to go through skin and muscles and damage the bone.

‘A similar but less powerful blow also damaged the second right front rib. Such blows were aimed at internal organs and/or blood vessels.

‘The mammoth was also hit in the left scapula at least three times. Two of these injuries were imparted by a weapon, which went downwards through the skin and muscles, moving from the top and side. These markings indicate injuries evidently left by relatively light throwing spears.

‘A much more powerful blow damaged the spine of the left scapula. It may have been imparted by a thrusting spear, practically straight from the front at the level of the coracoid process. The weapon went through the shoulder skin and muscle, almost completely perforating the spine of the scapula.

‘Taking into account the scapula’s location in the skeleton and the estimated height of this mammoth, the point of impact would be approximately 1500 mm high, in other words, the height of an adult human’s shoulder.’

Another injury – possibly evidence of a mis-directed blow – was spotted on the left jugal bone. The blow was evidently very strong and was suffered by the animal from the left back and from top down, which is only possible if the animal was lying down on the ground.

Dr Pitulko, of the Institute for the History of Material Culture in St Petersburg, believes that it was ‘the final blow’, which was aimed to the base of the trunk.

Modern elephant hunters still use this method ‘to cut major arteries and cause mortal bleeding’. Yet in this case the prehistoric hunters obviously missed and struck the jugal bone instead.

Luckily the spear left the clear trace on the bone, making possible to learn what kind of weapon it was.

The bone was studied with X-ray computed tomography – a CT scan – by Dr Konstantin Kuper, from the Budker Institute of Nuclear Physics in Novosibirsk. He also created a 3D model of the injury in the bone. This led to the conclusion that the tip of the weapon was made of stone and had a thinned symmetric outline – and was relatively sharp.

Paleontologist Dr Alexei Tikhonov, from the Zoological Institute of Russian Academy of Sciences in St Petersburg, who lead the excavations, said: ‘It’s hard to say which blow was the mortal one, at least judging by the traces on the bones.

‘There was quite a strong blow to the scapula, yet I think it was rather the totality of wounds that caused the death. It is interesting that the most of the injuries are on the left side of the animal.

‘I would suppose that the hunters could attack the mammoth which was already lying on the ground. When we examined the skull, we noticed the abnormal development of the upper jaw.

‘We believe that this mammoth got a kind of injury at a very young age, which impacted on its left side. There was no left tusk and I presume that the left side was weak, so it could help the hunters kill the animal.’

The injuries found on the bones also gave clues what did the hunters with the mammoth after they killed it. The right tusk had the traces of human interference on the tip of the tusk.

They did not try and pull the entire tusk off the killed mammal but instead tried to remove ‘long slivers of ivory with sharp edges, which were usable as butchering tools’, said Dr Pitulko.

A butchery mark was also found on the fifth left rib, seen as evidence that the hunters cut meat from the carcass to take it with them. Ancient man also extracted the mammoth tongue, seen as a probable delicacy to these hunters.

Yet the theory that the animal was butchered does not convince all experts.

Dr Robert Park, a professor of anthropology at the University of Waterloo in Canada, wrote in an email to Discover, that the skeleton is not consistent with other evidence from early human hunters.

He wrote: ‘The most convincing evidence that it wasn’t butchered is the fact that the archaeologists recovered the mammoth’s fat hump. Hunter-gatherers in high latitudes need fat both for its food value and as fuel. So the one part of the animal that we would not expect hunters to leave behind is fat.’

But Dr Pitulko countered: ‘Yes, ancient man – and not so ancient, in fact – has used and uses animal fat as fuel and food, nothing to argue about here. Why in this very case they did not use their prey in full is impossible to say.

‘There may be dozens of reasons, for example – they could not – the carcass was lying at the water’s edge, and it was late autumn. Or they did not have time: the carcass fell into the water on thin coastal ice. Or it did not correspond to their plans – they killed the poor animal just to have a meal and replenish the supply of food for a small group.’

They might have killed another animal nearer to their camp, and so abandoned this one. He said ‘a thousand and one reasons’ might explain not purloining the fat.

The expert added: ‘I believe that the main reason for hunting mammoths were their tusks. Mammoth as a source of food wasn’t very necessary although I believe they were useful.

‘People needed tusks because they were living in landscapes free of forests, so called mammoth steppe. In the course of time, a technology to produce spears out of tusks was developed.’

On the significance for the New World, he told Discovery the human role in killing the mammoth ‘is especially important’ because ‘now we know that eastern Siberia up to its Arctic limits was populated starting at roughly 50,000 years ago’.

 

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Arachis ipaensis, left, and Arachis duranensis, right, are the two species of wild peanut that crossed to provide the genetic blueprint for today's modern peanut varieties. (Credit: Merritt Melancon/University of Georgia)

Arachis ipaensis, left, and Arachis duranensis, right, are the two species of wild peanut that crossed to provide the genetic blueprint for today’s modern peanut varieties. (Credit: Merritt Melancon/University of Georgia)

Arachis ipaensis, one of the wild peanut varieties that helped to create the modern peanut, was found in the foothills of the Andes in Bolivia and Argentina in the 1970s. (Credit: Merritt Melancon/University of Georgia)

Arachis ipaensis, one of the wild peanut varieties that helped to create the modern peanut, was found in the foothills of the Andes in Bolivia and Argentina in the 1970s. (Credit: Merritt Melancon/University of Georgia)

 

Original Article:

News.uga.edu

Writer: J. Merritt Melanin, Feb 2016

 

Athens, Ga. – Researchers at the University of Georgia, working with the International Peanut Genome Initiative, have discovered that a wild plant from Bolivia is a “living relic” of the prehistoric origins of the cultivated peanut species.

The peanut that is grown by farmers today is the result of hybridization between two wild species. The hybrid was cultivated by ancient inhabitants of South America and, by selection, was transformed into today’s crop plant.

Comparisons of the DNA sequences of one of the wild species and the cultivated peanut showed that they are almost exactly same; in fact, they are 99.96 percent identical. It’s an unprecedented similarity.

“It’s almost as if we had traveled back in time and sampled the same plant that gave rise to cultivated peanuts from the gardens of these ancient people,” said David Bertioli, an International Peanut Genome Initiative, or IPGI, plant geneticist of the Universidade de Brasília, who is working at UGA.

This discovery forms part of a study that appears in this month’s Nature Genetics journal, published by the UGA-led IPGI. Scott Jackson, director of the UGA Center for Applied Genetic Technologies in the College of Agricultural and Environmental Sciences, serves as chair of the IPGI. Bertioli is lead author on the paper.

Because its ancestors were two different species, today’s peanut carries two separate genomes, designated “A” and “B” subgenomes. Their high similarity means they are very difficult to map out separately when sequencing the cultivated peanut genome. So, as a first step, researchers built their models using the two wild, ancestral peanut species collected by botanists in the wooded foothills of the Andes in Bolivia and Argentina decades ago.

The genome of one of them, Arachis duranensis, is about as similar to the A subgenome as could be expected. However, what really caught their attention was that the genome of the other species, A. ipaensis, was found to be virtually identical to the B subgenome.

Soon after its collection in 1971, the botanists who collected A. ipaensis realized that it was peculiar. The population of A. ipaensis was very small and isolated, and its closest relatives grew hundreds of miles to the north. They questioned how it arrived in the location where they found it growing.

Prompted by the extraordinary DNA identity, the scientists used information from decades-old botanical collections, knowledge of the seasonal movements of ancient hunter-gatherer-farmers and molecular DNA clock calculations to work out that the plants’ seeds had almost certainly been transported by humans about 10,000 years ago.

“Everything fit,” Bertioli said. “It’s the only place where A and B genome species have ever been found growing close together. The region is right next to the region where, even today, the most primitive types of cultivated peanut are grown, and the date is right in the time frame that plant domestication was happening in South America.”

The movement of the B genome species into the range of the A genome species meant that the hybridization could happen, probably courtesy of a native bee, and the cultivated peanut species was formed. The rest is history, Bertioli said.

The new peanut genome sequences were released in 2014 to researchers and plant breeders around the globe. Their use is advancing the breeding of more productive and more resilient peanut varieties. The paper in Nature Genetics represents the first official publication of the IPGI.

The effort to sequence the peanut genome took several years. While peanuts have been successfully bred for intensive cultivation, relatively little was known about the legume’s genetic structure because of its complexity, according to Peggy Ozias-Akins, a senior author on the paper and director of the UGA Institute of Plant Breeding, Genetics and Genomics. The sequences provide researchers access to 96 percent of all peanut genes and provide the DNA map needed to more quickly identify and genetically tag genes that confer desirable traits, such as drought- and disease-resistance.

A consortium of peanut growers, peanut shellers, brokers and food manufacturing groups provided $6 million in funding for the genome sequencing effort through The Peanut Foundation.

Victor Nwosu, program manager for Mars Chocolate and chairman of the board of directors of The Peanut Foundation, is enthusiastic about the advances these discoveries will facilitate.

“The peanut genome project will lead to reduction in production costs through development of disease-resistant varieties and improved yield for farmers, speed of selection and release of new varieties for breeders and potential for improvement of nutritional value of peanuts for consumers,” Nwosu said. “We are beginning to see these benefits already.”

The genome sequence assemblies and additional information are available at http://peanutbase.org/.

The International Peanut Genome Initiative brings together scientists from the U.S., China, Brazil, India, Australia, Japan and Israel to delineate peanut genome sequences, characterize the genetic and phenotypic variation in cultivated and wild peanuts and develop genomic tools for peanut breeding. The initial sequencing was carried out in Shenzhen, China, by the BGI, known previously as the Beijing Genomics Institute.

Assembly was done at the BGI, the U.S. Department of Agriculture Agricultural Research Service in Ames, Iowa, and the University of California, Davis. The project was funded by the peanut industry through The Peanut Foundation and by Mars Inc. and three Chinese academies: the Henan Academy of Agricultural Sciences, Chinese Academy of Agricultural Sciences and Shandong Academy of Agricultural Sciences.

A complete list of the institutions involved with the project and the other funding sources is available at http://peanutbioscience.com/.

The study, “The genome sequences of Arachis duranensis and Arachis ipaensis, the diploid ancestors of cultivated peanut,” will be available online at http://dx.doi.org/10.1038/ng.3517.

 

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