Ancient feces provides earliest evidence of infectious disease being carried on Silk Road

These are 2,000-year-old personal hygiene sticks with remains of cloth, excavated from the latrine at Xuanquanzhi.

An ancient latrine near a desert in north-western China has revealed the first archaeological evidence that travellers along the Silk Road were responsible for the spread of infectious diseases along huge distances of the route 2,000 years ago.

Cambridge researchers Hui-Yuan Yeh and Piers Mitchell used microscopy to study preserved faeces on ancient 'personal hygiene sticks' (used for wiping away faeces from the anus) in the latrine at what was a large Silk Road relay station on the eastern margins of the Tarim Basin, a region that contains the Taklamakan desert. The latrine is thought to date from 111 BC (Han Dynasty) and was in use until 109 AD.

They found that eggs from four species of parasitic worm (helminths) were present: roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), tapeworm (Taenia sp.), and Chinese liver fluke (Clonorchis sinensis).

Chinese liver fluke is a parasitic flatworm that causes abdominal pain, diarrhea, jaundice and liver cancer. It requires well-watered, marshy areas to complete its life cycle. Xuanquanzhi relay station was located at the eastern end of the arid Tarim Basin, an area that contains the fearsome Taklamakan Desert. The liver fluke could not have been endemic in this dry region.

In fact, based on the current prevalence of the Chinese liver fluke, its closest endemic area to the latrine's location in Dunhuang is around 1,500km away, and the species is most common in Guandong Province -- some 2,000km from Dunhuang.

Researchers from the University of Cambridge's Department of Archaeology and Anthropology, who conducted the study, suggest that the traveller infected with this liver fluke must have journeyed an enormous distance, and suggest the discovery provides the first reliable evidence for long distance travel with an infectious disease along the Silk Road.

The findings are published today in the Journal of Archaeological Science: Reports.

"When I first saw the Chinese liver fluke egg down the microscope I knew that we had made a momentous discovery," said Hui-Yuan Yeh, one of the study's authors. "Our study is the first to use archaeological evidence from a site on the Silk Road to demonstrate that travellers were taking infectious diseases with them over these huge distances."

The Silk Road (or Silk Route) came to prominence during the Han Dynasty in China (202 BC -- AD 220) as merchants, explorers, soldiers and government officials journeyed between East Asia and the Middle East/Mediterranean region.

Researchers have previously suggested that diseases such as bubonic plague, anthrax and leprosy might have been carried by ancient travellers along the legendary trading route, as similar strains have been found in China and Europe.

"Until now there has been no proof that the Silk Road was responsible for the spread of infectious diseases. They could instead have spread between China and Europe via India to the south, or via Mongolia and Russia to the north," says study lead Piers Mitchell.

The Cambridge team worked alongside Chinese researchers Ruilin Mao and Hui Wang from the Gansu Institute for Cultural Relics and Archaeology, who originally excavated the ancient latrine and relay station in Ganzu Province.

The stop was a popular one on the Silk Road with travellers staying there and government officials using the facility to change their horses and deliver letters. While excavating the latrine, the Chinese team found the personal hygiene sticks with cloth wrapped round one end.

Read more at Science Daily

Neural networks: Why larger brains are more susceptible to mental illnesses

Macaque brain showing the inter-areal network. Nodes roughly correspond to actual areas, thickness of lines proportional to the logarithm of the numbers of axons.

In humans and other mammals, the cerebral cortex is responsible for sensory, motor, and cognitive functions. Understanding the organization of the neuronal networks in the cortex should provide insights into the computations that they carry out. A study publishing on July 21st in open access journal PLOS Biology shows that the global architecture of the cortical networks in primates (with large brains) and rodents (with small brains) is organized by common principles. Despite the overall network invariances, primate brains have much weaker long-distance connections, which could explain why large brains are more susceptible to certain mental illnesses such as schizophrenia and Alzheimer disease.

In earlier work, Zoltán Toroczkai, from the University of Notre-Dame, USA, Mária Ercsey-Ravasz, from Babes-Bolyai University, Romania and Henry Kennedy, from the University Lyon, France, and colleagues combined tracing studies in macaques, which visualize connections in the brain, with network theory to show that the cortical network structure in this primate is governed by the so-called exponential distance rule (EDR).

The EDR describes a consistent relationship between distances and connection strength. Consistent with the tracing results, the EDR predicts that there are many fewer long-range axons (nerve fibers that function as transmission lines of the nervous system) than short ones, and this can be quantified by a mathematical equation. At the level of cortical areas (such as visual cortex or auditory cortex) examined by the tracing studies, this means the closer two areas are to each other, the more connections exist between them.

In this study, the researchers compare the features of the cortical networks in the macaque -- a mammal with a large cortex -- with those in the mouse, with its much smaller cortex. They used detailed tracing data to quantify connections between functional areas, and those formed the basis for the analysis. Despite the substantial differences in the cortex size between the species and other apparent differences in cortex organization, they found that the fundamental statistical features of all networks followed the EDR.

Based on these results, the researchers hypothesize that the EDR describes an effective design principle that remains constant during the evolution of mammalian brains of different sizes. They present mathematical arguments that support the universal applicability of the EDR as a governing principle of cortical connectivity, as well as further experimental support from high-resolution tracer experiments in small brain areas from macaque, mouse, and mouse lemur (a primate with a very small brain).

Their results, the researchers conclude, "suggest that the EDR plays a key role across the mammalian order to optimize the layout of the inter-areal cortical network allowing larger-brained animals to maintain communication efficiencies combined with increased neuron numbers."

Read more at Science Daily

How rope was made 40,000 years ago

Rope making tool from mammoth ivory from Hohle Fels Cave in southwestern Germany, ca. 40,000 years old.

Prof. Nicholas Conard and members of his team, present the discovery of a tool used to make rope in today‘s edition of the journal: Archäologische Ausgrabungen Baden-Württemberg.

Rope and twine are critical components in the technology of mobile hunters and gatherers. In exceptional cases impressions of string have been found in fired clay and on rare occasions string was depicted in the contexts of Ice Age art, but on the whole almost nothing is known about string, rope and textiles form the Paleolithic.

A key discovery by Conard’s team in Hohle Fels Cave in southwestern Germany and experimental research and testing by Dr. Veerle Rots and her team form the University of Liège is rewriting the history of rope.

The find is a carefully carved and beautifully preserved piece of mammoth ivory 20.4 cm in length with four holes between 7 and 9 mm in diameter. Each of the holes is lined with deep, and precisely cut spiral incisions. The new find demonstrates that these elaborate carvings are technological features of rope-making equipment rather than just decoration.

Similar finds in the past have usually been interpreted as shaft-straighteners, decorated artworks or even musical instruments. Thanks to the exceptional preservation of the find and rigorous testing by the team in Liège, the researchers have demonstrated that the tool was used for making rope out of plant fibers available near Hohle Fels. “This tool answers the question of how rope was made in the Paleolithic”, says Veerle Rots, “a question that has puzzled scientists for decades.”

Excavators found the rope-making tool in archaeological horizon Va near the base of the Aurignacian deposits of the site. Like the famous female figurines and the flutes recovered from the Hohle Fels, the rope-making tool dates to about 40,000 years ago, the time when modern humans arrived in Europe. The discovery underlines the importance of fiber technology and the importance of rope and string for mobile hunters and gatherers trying to cope with challenges of life in the Ice Age.

Prof. Conard’s team has excavated at Hohle Fels over each of the last 20 years, and it is this long-term commitment that has over and over again paid off, to make Hohle Fels one of the best known Paleolithic sites worldwide. Hohle Fels and neighboring sites from the Ach and Lone Valleys have been nominated for UNESCO World Cultural Heritage status. The excavations at Hohle Fels near Schelklingen in the Ach Valley are funded by the HeidelbergCement AG, the Ministry of Science of Baden-Württemberg and the Heidelberger Academie of Sciences.

Read more at Science Daily

A new key to understanding molecular evolution in space

Ortho-hydrogen converts to para-hydrogen by releasing energy to the ice surface. The conversion rate differed depending on the ice temperature.

Scientists at Hokkaido University have revealed temperature-dependent energy-state conversion of molecular hydrogen on ice surfaces, suggesting the need for a reconsideration of molecular evolution theory.

Molecular hydrogen, the most abundant element in space, is created when two hydrogen atoms bond on minute floating ice particles. It has two energy states: ortho and para, depending on the direction of proton spins. Ortho-hydrogen converts to para-hydrogen on extremely low temperature ice particles, though its mechanism remained unclear.

When molecular hydrogen is released from tiny ice particles in space, the particular state of its energy plays a key role in molecular evolution -- the process of generating a wide range of molecules over a long period of time in space.

In the study, the researchers developed a special system that could detect the ortho/para ratio of molecular hydrogen on artificial ice particles. The study discovered that the ratio of the ortho-to-para conversion rate (as time passed) was dramatically different in the relatively small temperature range of between -264C and -257C, thus, in a world first, unraveling the conversion mechanism. Ortho-hydrogen converts to para-hydrogen by releasing energy to the ice, in a temperature dependent manner.

Until now, the energy conversion rate was believed to be identical regardless of the temperature of ice particles -- a theory that has been scotched by the new research. The finding will likely prompt scientists to rebuild theories of molecular evolution, opening new horizons in studies of molecular formation and molecular evolution.

From Science Daily

Neanderthals in Germany: First population peak, then sudden extinction

Neanderthal depiction (stock image). Neanderthals lived in the Middle Paleolithic, the middle period of the Old Stone Age. This period encompasses the time from roughly 200,000 to 40,000 before our times.

Neanderthals once populated the entire European continent. Around 45,000 years ago, Homo neanderthalensis was the predominant human species in Europe. Archaeological findings show that there were also several settlements in Germany. However, the era of the Neanderthal came to an end quite suddenly.

Based on an analysis of the known archaeological sites, Professor Jürgen Richter from Collaborative Research Center 806 -- Our Way to Europe, in which the universities of Cologne, Bonn and Aachen cooperate, comes to the conclusion that Neanderthals reached their population peak right before their population rapidly declined and they eventually became extinct.

Neanderthals lived in the Middle Paleolithic, the middle period of the Old Stone Age. This period encompasses the time from roughly 200,000 to 40,000 before our times. In his article published in the Quaternary International Journal, Richter comes to the conclusion that more than 50 percent of the known Neanderthal settlement sites in Germany can be dated to the Middle Paleolithic. More precisely, they date back 60,000 to 43,000 years before our times. Thus, the Neanderthal population peak seems to lie in this period.

The number of sites, their analysis and the analysis of the artefacts found at these settlements indicate that the Neanderthal population in Germany was subject to extreme demographic fluctuations. During the Middle Paleolithic, there appear to have been several migrations, population increase and decline, extinction in certain areas and then a return of settlers to these areas.

While for the time period between 110,000 to 70,000 years ago there are only four known settlement sites, in the following period from 70,000 to 43,000 years ago there are ninety-four. In less than 1,000 years after this demographic peak, however, there was a rapid decline and the Neanderthal disappeared from the scene. Precisely why the species died out is still unclear. Perhaps it was due to low genetic diversity, perhaps to the rise of Homo sapiens. This question will continue to occupy scientists.

From Science Daily

Human Gut Bacteria Took Root Before We Were Human

The relationship between humans and the bacteria in our guts extends far back into the past — to the time before modern humans even existed, a new study finds.

Microbes in two bacterial families — Bacteroidaceae and Bifidobacteriaceae, which are present in humans and African apes — likely colonized the guts of a shared ancestor of both groups around 15 million years ago, the researchers discovered.

Since then, the bacteria have inhabited the digestive systems of humans and apes for thousands of generations.

The researchers' genetic data also tell a story of parallel evolution — in the microbes, and in the primate hosts they inhabited.

"Just like we share a common ancestor with chimpanzees about 6 million years ago, a lot of our gut bacteria share a common ancestor with chimpanzee gut bacteria, which diverged around the same time," said study co-author Andrew Moeller, a postdoctoral researcher at the University of California at Berkeley.

"And the same is true for human and gorilla gut bacteria. We share a common ancestor maybe about 15 million years ago, and we found that some of our gut bacteria shared common ancestry about the same time," Moeller said in a statement.

Recent research has shown that humans' complex communities of gut microbes may influence our immune systems, and may be associated with certain moods and behaviors.

This new study provides the first evidence of when in our evolutionary history those microbes may have colonized us, the researchers said.

Previous findings enabled the researchers to identify an animal species purely from the groups of microbes in their gut, study co-author Howard Ochman, a professor of integrative biology at the University of Texas at Austin, said in a statement.

Read more at Discovery News

Farming Began in Two Separate Places in the Mideast

The Fertile Crescent and the Middle East, seen from space.

The reason that you're able to sit in a comfortable chair in your home and read this article on your tablet or laptop is that many thousands of years ago, humans shifted from being nomadic hunter-gatherers to raising their own food crops and domesticating animals. That breakthrough enabled our species to stay in one place long enough to build villages, towns and cities, and to start developing the technologies that eventually led to the advanced civilization we have today.

But who actually was the first to invent farming? A new genetic study suggests that two different groups of people in the Middle East independently developed agriculture, and then gradually spread their practices to Europe, Africa and Asia.

In the study, which recently was published online at Biorxiv.org, researchers looked at the genomes of 44 individuals who lived between 3,500 and 14,000 years ago in present-day Armenia, Turkey, Israel, Jordan and Iran. The difficult-to-obtain ancient DNA was extracted from a tiny ear bone -- called the petrous -- by a team led by Losif Lazaridis and David Reich, two population geneticists at Harvard Medical school.

The team found stark differences between the genomes of ancient people on the southern side of the region in Israel and Jordan, and those on the other side of the Zagros mountains in western Iran. That pattern is consistent with existing evidence that the two groups didn't mingle, and separately developed the ability to grow crops.

"There has been a school of thought arguing that everything happens first in the southern Levant and everyone learns how to be farmers from this initial dispersal," Roger Matthews, an archaeologist at the University of Reading, U.K., who co-directs the Central Zagros Archaeological Project in Iran, explained in a Nature.com article. "But the archaeological evidence shows very strong local traditions that are clearly not in communication with each other, persisting for centuries if not millennia."

Agriculture seems to have developed about 11,000 years ago in those places. The two groups also focused on different agricultural products, with the southern farmers domesticating goats and growing cereals such as emmer, while the western group cultivated barley and wheat.

About 9,500 years ago, the two populations of farmers finally may have mixed in eastern Turkey, where they probably were searching for sources of obsidian, which they needed to make tools. By the time farmers from Turkey began migrating to Europe, they had what the researchers call a "Neolithic Toolkit," which included crops, animals and tools from both farming traditions.

From Discovery News

Beyond Star Trek: Hubble Probes the Final Frontier

The Hubble Space Telescope continues to use massive galactic clusters to create natural cosmic lenses to superboost its observing powers.

Just as "Star Trek Beyond" hits theaters, Hubble has released its own view of the final frontier.

Located some four billion light-years away, the Abell S1063 galaxy cluster creates a dazzling scene. The sheer mass of the cluster has corralled light from galaxies that exist way beyond Hubble's observing capabilities, creating those strange-looking arcs and warped galactic shapes.

The light from these far-away galaxies travels through the cluster, but as the space-time surrounding the cluster is warped by its mass, the light is deflected -- a bit like how the path of light is refracted through a magnifying lens. And it has the same effect; distant objects are magnified by these cosmic lenses, boosting Hubble's already impressive magnification. This is known as gravitational lensing and it is a direct prediction from Einstein's theory of general relativity.

The coolest thing is that Abell S1063 contains images of 16 background galaxies and one of those primordial galaxies existed only a billion years after the Big Bang. This ancient specimen comes from the first generation of galaxies to appear in the universe, so its light has taken nearly 13 billion years to travel from that galaxy, through the space-time magnification in the Abell S1063 cluster and into Hubble's lens.

Though seeing galaxies from the dawn of the universe is a scientific goldmine in itself, measurements of their distorted shapes can help astronomers map the distribution of dark matter within the cluster, helping us further refine our theories on what this mysterious mass could be.

Abell S1063, a galaxy cluster, was observed by the NASA/ESA Hubble Space Telescope as part of the Frontier Fields program. The huge mass of the cluster acts as a cosmic magnifying glass and enlarges even more distant galaxies.

This most recent observation is a part of Hubble's Frontier Fields program that really pushes the envelope for the veteran telescope. By combining Hubble's unobstructed view of the visible universe and using this quirk of general relativity, we are learning so much more about the early universe, spying some galaxies that existed only a few hundred million years after the birth of the universe and providing compelling new clues as to the nature of some of the biggest mysteries beyond our current cosmological understanding.

Read more at Discovery News

Genome of 6,000-year-old barley grains sequenced for first time

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

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.

Read more at Science Daily

Super-eruptions may give a year's warning before they blow

One of the 73 quartz crystals used in the study. They averaged about one millimeter in diameter.

Super-eruptions -- volcanic events large enough to devastate the entire planet -- give only about a year's warning before they blow.

That is the conclusion of a new microscopic analysis of quartz crystals in pumice taken from the Bishop Tuff in eastern California, which is the site of the super-eruption that formed the Long Valley Caldera 760,000 years ago.

The study is described in the paper "The year leading to a supereruption" by Guilherme Gualda, associate professor of earth and environment sciences at Vanderbilt University, and Stephen Sutton at the University of Chicago published July 20 in the journal PLOS One.

"The evolution of a giant, super-eruption-feeding magma body is characterized by events taking place at a variety of time scales," said Gualda. Tens of thousands of years are needed to prime the crust to generate sufficient eruptible magma. Once established, these melt-rich, giant magma bodies are unstable features that last for only centuries to few millennia. "Now we have shown that the onset of the process of decompression, which releases the gas bubbles that power the eruption, starts less than a year before eruption."

Gualda and Sutton analyzed dozens of small quartz crystals from the Bishop Tuff. Previous investigations of quartz crystals from several super-eruptions, including Long Valley, have noted that they have distinctive surface rims. These studies concluded that the rims formed in less than a century before eruption.

The new study uses a more accurate method for measuring rim growth times pinned on variations in the concentration of titanium in the crystal. Titanium is one of the few impurities that is incorporated into quartz in appreciable amounts and it diffuses fast enough to permit probing of time scales as short as minutes. However, it is extremely difficult to measure the small levels of titanium involved at sufficient spatial resolution. So the researchers established that the concentration of titanium in quartz directly correlates with the amount of light produced when a material is bombarded by electrons, an effect called cathodoluminescence. This allowed them to use cathodoluminescence images to make high-resolution measurements of variations in titanium concentration and, based on this, to determine rim growth times and growth rates.

"Maximum rim growth times span from approximately 1 minute to 35 years, with a median of approximately 4 days. More than 70 percent of rim growth times are less than 1 year, showing that quartz rims have mostly grown in the days to months prior to eruption... . Growth took place under conditions of high supersaturation suggesting that rim growth marks the onset of decompression and the transition from pre-eruptive to syn-eruptive conditions," the paper summarized.

According to Gualda, the decompression period would likely be accompanied by the expansion of the magma body which should have detectable effects on the Earth's surface. While more work is needed to understand what exactly the signs at the surface would be, the study suggests that signs of an impending super-eruption would start to be felt within a year of eruption, and they would intensify as the eruption neared.

Very large eruptions -- including super-eruptions -- have taken place in a number of places worldwide in the recent geological past. The Taupo Volcanic Zone in New Zealand was the site of the most recent super-eruption -- the Oruanui eruption at 26,500 years -- and it includes deposits from more than a dozen very large eruptions that took place in the last couple of million years. Campi Flegrei in Italy produced a very large eruption 40,000 years ago. Indonesia was the site of the Toba super-eruption in Sumatra 75,000 years ago and the Tambora eruption in 1815. In the United States, Yellowstone has experienced three super-eruptions over the last two million years. In light of this evidence, it seems inevitable that another super-eruption will strike the Earth in the future.

Read more at Science Daily