It Took Earth Ten Million Years to Recover from Greatest Mass Extinction

It took some 10 million years for Earth to recover from the greatest mass extinction of all time, latest research has revealed.

Life was nearly wiped out 250 million years ago, with only 10 per cent of plants and animals surviving. It is currently much debated how life recovered from this cataclysm, whether quickly or slowly.

Recent evidence for a rapid bounce-back is evaluated in a new review article by Dr Zhong-Qiang Chen, from the China University of Geosciences in Wuhan, and Professor Michael Benton from the University of Bristol. They find that recovery from the crisis lasted some 10 million years, as explained May 27 in Nature Geoscience.

There were apparently two reasons for the delay, the sheer intensity of the crisis, and continuing grim conditions on Earth after the first wave of extinction.

The end-Permian crisis, by far the most dramatic biological crisis to affect life on Earth, was triggered by a number of physical environmental shocks -- global warming, acid rain, ocean acidification and ocean anoxia. These were enough to kill off 90 per cent of living things on land and in the sea.

Dr Chen said: "It is hard to imagine how so much of life could have been killed, but there is no doubt from some of the fantastic rock sections in China and elsewhere round the world that this was the biggest crisis ever faced by life."

Current research shows that the grim conditions continued in bursts for some five to six million years after the initial crisis, with repeated carbon and oxygen crises, warming and other ill effects.

Some groups of animals on the sea and land did recover quickly and began to rebuild their ecosystems, but they suffered further setbacks. Life had not really recovered in these early phases because permanent ecosystems were not established.

Professor Benton, Professor of Vertebrate Palaeontology at the University of Bristol, said: "Life seemed to be getting back to normal when another crisis hit and set it back again. The carbon crises were repeated many times, and then finally conditions became normal again after five million years or so."

Finally, after the environmental crises ceased to be so severe, more complex ecosystems emerged. In the sea, new groups, such as ancestral crabs and lobsters, as well as the first marine reptiles, came on the scene, and they formed the basis of future modern-style ecosystems.

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Hubble Sees a Spiral Within a Spiral

NASA's Hubble Space Telescope captured a new image of the spiral galaxy known as ESO 498-G5. One interesting feature of this galaxy is that its spiral arms wind all the way into the center, so that ESO 498-G5's core looks like a bit like a miniature spiral galaxy. This sort of structure is in contrast to the elliptical star-filled centers (or bulges) of many other spiral galaxies, which instead appear as glowing masses.

Astronomers refer to the distinctive spiral-like bulge of galaxies such as ESO 498-G5 as disc-type bulges, or pseudobulges, while bright elliptical centers are called classical bulges. Observations from the Hubble Space Telescope, which does not have to contend with the distorting effects of Earth's atmosphere, have helped to reveal that these two different types of galactic centers exist. These observations have also shown that star formation is still going on in disc-type bulges and has ceased in classical bulges. This means that galaxies can be a bit like Russian matryoshka dolls: classical bulges look much like a miniature version of an elliptical galaxy, embedded in the center of a spiral, while disc-type bulges look like a second, smaller spiral galaxy located at the heart of the first -- a spiral within a spiral.

The similarities between types of galaxy bulge and types of galaxy go beyond their appearance. Just like giant elliptical galaxies, the classical bulges consist of great swarms of stars moving about in random orbits. Conversely, the structure and movement of stars within disc-type bulges mirror the spiral arms arrayed in a galaxy's disc. These differences suggest different origins for the two types of bulges: while classical bulges are thought to develop through major events, such as mergers with other galaxies, disc-type bulges evolve gradually, developing their spiral pattern as stars and gas migrate to the galaxy's center.

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Teen Solves 350-Year-Old Math Problem

A boy math whiz has shocked the world by solving a 350-year-old problem once posed by the great mathematician, Sir Isaac Newton.

Sixteen-year-old Shouryya Ray, a boy of Indian origin attending school in Germany, cracked two particle dynamics theories. Ray's novel solutions can now help scientists calculate the flight path of a thrown ball and predict how it will strike and bounce off a wall, according to the International Business Times.

Ray was told by professors during a school field trip to Dresden University that the problem could not be solved. That notion didn't sit right with the Calcutta-born student.

"I just asked myself, 'Why not?'" Ray told Germany's Welt Online newspaper. "I didn't believe there couldn't be a solution."

According to Welt Online, Ray has been captivated by math since a very early age and was inspired by his father, Subhashis Ray, who works as a research assistant at the Technical University of Freiburg. His father began teaching Ray calculus at the tender age of six.

Ray's family moved to Germany when he was 12. Ray didn't speak German when they first moved to Germany and now he is fluent in the language.

As for his future career, Ray is debating whether to study math or physics when he moves on to college.

From Discovery News

NASA Wanted Astronauts to View Venus Up-Close

In a little over a week, we’re all going to be looking skyward and focusing our sights (safely) on Venus as it crosses the disk of the sun. It's going to be a fantastic view, especially since most of us only ever see Venus as a tiny dot of light in the sky. But in 1967, NASA considered giving three astronauts a really rare view of Venus by sending them on a flyby around the second planet from the sun.

The mission was developed under the Apollo Applications Program (AAP) that was designed to build on and apply Apollo-era technology to greater goals in space. Out of the AAP NASA hoped to see Earth orbiting laboratories, research stations on the moon, and manned interplanetary missions. In 1967, this was America’s future in space.

One of the interplanetary targets was Venus. After visiting the planet with the unmanned Mariner 2 spacecraft in 1962, NASA learned that the planet lacks a strong magnetic field, has an extremely hot surface generated in the lower atmosphere or surface, and that the cosmic radiation in the interplanetary space was survivable. NASA also learned that it was worth going back. There was undoubtedly more to Venus locked under its thick cloud cover.

To get a crew there, NASA would use a revised Apollo spacecraft. Like the lunar missions, it was a tripartite design composed of a Command and Service Module (CSM), and Environmental Support Module (ESM), and a third habitable section. Here’s how the mission was designed to play out.

A three-man crew, nestled in the CM, would launch on a Saturn V. The CSM would perform the same functions it did during the Apollo lunar missions: its onboard computer would serve as the primary guidance and navigation system, provide the main reaction control, and act as the principle telemetry and communications link with mission control. Really, the mission would be a simple of matter of engineers rewriting the computer’s commands to send the crew to Venus instead of the moon. The hard part is keeping them alive and well during the 400 day mission. This is where the other modules come into play.

With no purpose for a Lunar Module on a Venus flyby, the spidery spacecraft would be swapped out for the larger ESM. Once in Earth orbit, the crew would separate the CSM from the rest of the spacecraft, turn around, and dock with the ESM. Then they could open the hatch and transfer between the vehicles. The ESM was designed as the principle experiment bay on the mission and would provide long term life support and environmental control to the whole spacecraft configuration.

With the CSM and ESM docked, the Saturn V’s upper SIV-B stage would fire and send the whole thing towards Venus. But instead of jettisoning the spent rocket stage, the crew would re-purpose it -- neither of the other two module gave them a comfortable living space. In the ESM the astronauts would have everything they’d need to refurbish the rocket stage and turn it into their main habitable module and recreational space. Solar panels lining the outside would provide power to the whole spacecraft.

The mission planned to launch sometime during the month-long window between Oct. 31 and Nov. 30 1973; the dates offered a quick transit to Venus and the year was expected to be a quiet one for solar activity, minimizing the crew’s exposure to dangerous solar radiation.

The outbound leg of the mission was expected to last 123 days. The crew would arrive at Venus sometime in the month of March 1974 and pass just 3,340 nautical miles -- about 3,834 statute miles -- above the surface as they whipped around to begin the 273 day trip back to Earth. The mission would end in a splashdown sometime in December 1974.

Read more at Discovery News

New Genetic Method Developed to Pinpoint Individuals' Geographic Origin

Understanding the genetic diversity within and between populations has important implications for studies of human disease and evolution. This includes identifying associations between genetic variants and disease, detecting genomic regions that have undergone positive selection and highlighting interesting aspects of human population history.

Now, a team of researchers from the UCLA Henry Samueli School of Engineering and Applied Science, UCLA's Department of Ecology and Evolutionary Biology and Israel's Tel Aviv University has developed an innovative approach to the study of genetic diversity called spatial ancestry analysis (SPA), which allows for the modeling of genetic variation in two- or three-dimensional space.

Their study is published online this week in the journal Nature Genetics.

With SPA, researchers can model the spatial distribution of each genetic variant by assigning a genetic variant's frequency as a continuous function in geographic space. By doing this, they show that the explicit modeling of the genetic variant frequency -- the proportion of individuals who carry a specific variant -- allows individuals to be localized on a world map on the basis of their genetic information alone.

"If we know from where each individual in our study originated, what we observe is that some variation is more common in one part of the world and less common in another part of the world," said Eleazar Eskin, an associate professor of computer science at UCLA Engineering. "How common these variants are in a specific location changes gradually as the location changes.

"In this study, we think of the frequency of variation as being defined by a specific location. This gives us a different way to think about populations, which are usually thought of as being discrete. Instead, we think about the variant frequencies changing in different locations. If you think about a person's ancestry, it is no longer about being from a specific population -- but instead, each person's ancestry is defined by the location they're from. Now ancestry is a continuum."

The team reports the development of a simple probabilistic model for the spatial structure of genetic variation, with which they model how the frequency of each genetic variant changes as a function of the location of the individual in geographic space (where the gene frequency is actually a function of the x and y coordinates of an individual on a map).

"If the location of an individual is unknown, our model can actually infer geographic origins for each individual using only their genetic data with surprising accuracy," said Wen-Yun Yang, a UCLA computer science graduate student.

"The model makes it possible to infer the geographic ancestry of an individual's parents, even if those parents differ in ancestry. Existing approaches falter when it comes to this task," said UCLA's John Novembre, an assistant professor in the department of ecology and evolution.

SPA is also able to model genetic variation on a globe.

"We are able to also show how to predict the spatial structure of worldwide populations," said Eskin, who also holds a joint appointment in the department of human genetics at the David Geffen School of Medicine at UCLA. "In just taking genetic information from populations from all over the world, we're able to reconstruct the topology of the global populations only from their genetic information."

Using the framework, SPA can also identify loci showing extreme patterns of spatial differentiation.

"These dramatic changes in the frequency of the variants potentially could be due to natural selection," Eskin said. "It could be that something in the environment is different in different locations. Let's say a mutation arose that has some advantageous property in a certain environment. So you can imagine then that a kind of force for genetic selection would make this mutation more common in that environment."

Read more at Science Daily

It's in the Genes: Research Pinpoints How Plants Know When to Flower

Scientists believe they've pinpointed the last crucial piece of the 80-year-old puzzle of how plants "know" when to flower.

Determining the proper time to flower, important if a plant is to reproduce successfully, involves a sequence of molecular events, a plant's circadian clock and sunlight.

Understanding how flowering works in the simple plant used in this study -- Arabidopsis -- should lead to a better understanding of how the same genes work in more complex plants grown as crops such as rice, wheat and barley, according to Takato Imaizumi, a University of Washington assistant professor of biology and corresponding author of a paper in the May 25 issue of the journal Science.

"If we can regulate the timing of flowering, we might be able to increase crop yield by accelerating or delaying this. Knowing the mechanism gives us the tools to manipulate this," Imaizumi said. Along with food crops, the work might also lead to higher yields of plants grown for biofuels.

At specific times of year, flowering plants produce a protein known as FLOWERING LOCUS T in their leaves that induces flowering. Once this protein is made, it travels from the leaves to the shoot apex, a part of the plant where cells are undifferentiated, meaning they can either become leaves or flowers. At the shoot apex, this protein starts the molecular changes that send cells on the path to becoming flowers.

Changes in day length tell many organisms that the seasons are changing. It has long been known that plants use an internal time-keeping mechanism known as the circadian clock to measure changes in day length. Circadian clocks synchronize biological processes during 24-hour periods in people, animals, insects, plants and other organisms.

Imaizumi and the paper's co-authors investigated what's called the FKF1 protein, which they suspected was a key player in the mechanism by which plants recognize seasonal change and know when to flower. FKF1 protein is a photoreceptor, meaning it is activated by sunlight.

"The FKF1 photoreceptor protein we've been working on is expressed in the late afternoon every day, and is very tightly regulated by the plant's circadian clock," Imaizumi said. "When this protein is expressed during days that are short, this protein cannot be activated, as there is no daylight in the late afternoon. When this protein is expressed during a longer day, this photoreceptor makes use of the light and activates the flowering mechanisms involving FLOWERING LOCUS T. The circadian clock regulates the timing of the specific photoreceptor for flowering. That is how plants sense differences in day length."

This system keeps plants from flowering when it's a poor time to reproduce, such as the dead of winter when days are short and nights are long.

The new findings come from work with the plant Arabidopsis, a small plant in the mustard family that's often used in genetic research. They validate predictions from a mathematical model of the mechanism that causes Arabidopsis to flower that was developed by Andrew Millar, a University of Edinburgh professor of biology and co-author of the paper.

"Our mathematical model helped us to understand the operating principles of the plants' day-length sensor," Millar said. "Those principles will hold true in other plants, like rice, where the crop's day-length response is one of the factors that limits where farmers can obtain good harvests. It's that same day-length response that needs controlled lighting for laying chickens and fish farms, so it's just as important to understand this response in animals.

"The proteins involved in animals are not yet so well understood as they are in plants but we expect the same principles that we've learned from these studies to apply."

Read more at Science Daily

Structure of Human Protein Critical for Silencing Genes Solved

In a study published in the journal Cell on May 24, Cold Spring Harbor Laboratory (CSHL) scientists describe the three-dimensional atomic structure of a human protein bound to a piece of RNA that "guides" the protein's ability to silence genes. The protein, Argonaute-2, is a key player in RNA interference (RNAi), a powerful cellular phenomenon that has important roles in diverse biological processes, including an organism's development.

"Detailed knowledge of the structure of human Argonaute-2 and the way it interacts with its RNA guides will greatly improve our understanding of its biological mechanism of action," says CSHL Professor and HHMI Investigator Leemor Joshua-Tor, Ph.D., the study's leader. "Such precise structural information of the human Argonaute bound to an important RNA guide could potentially aid both basic research to understand the function of genes and also advance the development of RNAi as a therapeutic strategy in clinical settings."

Upon the activation of a gene within a cell, the gene's DNA is copied into a messenger RNA (mRNA) "transcript." The instructions encoded within this transcript are then used as a blueprint by the cell's protein synthesis machinery to generate a working protein. The gene is "silenced" or prevented from giving rise to the protein, however, when an Argonaute-2 protein that is bound to a small piece of "guide" RNA -- either a short-interfering RNA or a microRNA -- intercepts the mRNA molecule. The guide RNA, whose nucleotide sequence matches that of the target mRNA, acts as a homing device that helps the Argonaute-2 protein zero in on the mRNA target.

A few years ago, Joshua-Tor collaborated with CSHL Professor and HHMI Investigator Gregory Hannon, Ph.D., who is also a co-author in this study, to show that Argonaute proteins, which are made up of different domains or parts, act like a pair of molecular scissors that slice up target mRNAs, thus preventing proteins from being made and enforcing the silencing of their genes. The discovery of the Argonautes' "slicer" activity stemmed in part from solving the crystal structure of an Argonaute protein from Pyrococcus furiosus, an archebacterium that thrives in extremely high temperatures.

"But we still know nothing about the biological functions or mechanisms of action of archebacterial Argonautes," says Joshua-Tor. "We therefore next focused on solving the structures of Argonautes from higher organisms such as mammals, in which Argonaute functions and target recognition are well documented."

Joshua-Tor's team and other research groups subsequently determined the atomic structures of individual parts of Argonaute proteins from higher organisms. While these studies revealed several important details -- for example, the interaction between two parts of the Argonaute protein, called the PAZ and Mid domains, with the two ends of guide RNAs -- Joshua-Tor's goal was to solve the structure of the entire human Argonaute protein in complex with a single human guide RNA.

Overcoming a complicated series of technical challenges, her team has achieved this goal by analyzing the structure of a full-length human Argonaute-2 protein bound to a small RNA called miR-20a, which is known to play a role in cancer development. Although Argonautes from higher organisms diverged from their archebacterial cousins more than three billion years ago, the team's analysis shows remarkable similarity between the two structures, especially in the regions that are important for target recognition and slicing activity.

"Our structure shows that the guide RNA, which is anchored at both ends by the PAZ and Mid domains, kinks and twists its way through the structure of the entire protein, making several points of contact within each domain and with the linker loops that join them," explains Joshua-Tor. "The guide RNA thus acts like a backbone that rigidly locks together the otherwise flexible Argonaute protein and gives it stability."

Read more at Science Daily

Bigfoot: Beyond Footprints and DNA

Last week researchers from Oxford University and the Lausanne Museum of Zoology announced that they are seeking genetic materials (such as hair, skin, and blood samples) claimed to be of unknown animals such as Bigfoot. The goal of the Oxford-Lausanne Collateral Hominid Project is to catalogue and identify new species, including those long believed to be mythical.

Despite the publicity that the new project is garnering, this is far from the first time that alleged Bigfoot samples have been subjected to scientific testing.

In 2008, for example, the TV show "Destination Truth" recovered what was claimed to be a hair of a Yeti (formerly known as the Abominable Snowman). An analysis reportedly came back indicating that the sample contained "an unknown DNA sequence," though the full report was not made public and the results were never published in a journal -- as would be expected with a legitimate scientific discovery.

Then there was the strange case of a finger long claimed to be from a Yeti, once held in a monastery in Nepal which was examined by researchers at the Edinburgh Zoo last year. DNA testing solved the decades-old mystery and debunked the Yeti finger; it was actually human, probably from a monk.

For over a year Bigfoot buffs have followed the saga of Dr. Melba Ketchum, a veterinarian who claims to have definitive evidence of Bigfoot DNA. Ketchum says that her research will be published in a peer-reviewed scientific journal any time now, and has released virtually no information about her allegedly world-shaking findings, reminding those who question her that "until it is published, I cannot discuss our data at all."

Last week in a May 18 Facebook post, Ketchum once again promised that definitive Bigfoot DNA results would be published soon, and "that all is well and things are happening as expected."

'Unknown' and 'Unidentified'

The most compelling evidence for Bigfoot would be DNA analyses, since they are scientific and theoretically definitive. However answers are not always possible; "unknown" or "unidentified" results do not mean "Bigfoot."

There are many reasons why a given hair or DNA sample might come back unknown, including that it was contaminated or too degraded by environmental conditions. Or it could simply mean that the animal it came from was not among the reference samples that the laboratory used for comparison. We have no reference sample of Bigfoot DNA to compare it to, so by definition there cannot be a "conclusive match."

In his book Big Footprints (Johnson Books, 1992), veteran researcher Grover Krantz discussed alleged Bigfoot hair, feces, skin scrapings, and blood: "The usual fate of these items is that they either receive no scientific study, or else the documentation of that study is either lost or unobtainable. In most cases where competent analyses have been made, the material turned out to be bogus or else no determination could be made."

Indeed, twenty years later, the situation remains the same. When a definite conclusion has been reached through scientific analysis, the samples have invariably turned out to have prosaic sources -- "Bigfoot hair" turns out to be elk, bear, or cow hair, for example, or "Bigfoot blood" is revealed to be a car's transmission fluid.

Krantz gave one typical example: "A large amount of what looks like hair has been recovered from several places in the Blue Mountains since 1987. Samples of this were examined by many supposed experts ranging from the FBI to barbers. Most of these called it human, the Redkin Company found significant differences from human hair, but the Japan Hair Medical Science Lab declared it a synthetic fiber.

A scientist at [Washington State] University first called it synthetic, then looked more closely and decided it was real hair of an unknown type... However final confirmation came when E.B. Winn, a pharmaceutical businessman from Switzerland had a sample tested in Europe. The fiber was positively identified as artificial and its exact composition was determined: it is a product known commercially as Dynel, which is often used as imitation hair."

Read more at Discovery News

Like Curry? New Biological Role Identified for Compound Used in Ancient Medicine

Oregon State University scientists just identified a new reason why some curry dishes, made with spices humans have used for thousands of years, might be good for you.

New research has discovered that curcumin, a compound found in the cooking spice turmeric, can cause a modest but measurable increase in levels of a protein that's known to be important in the "innate" immune system, helping to prevent infection in humans and other animals.

This cathelicidin antimicrobial peptide, or CAMP, is part of what helps our immune system fight off various bacteria, viruses or fungi even though they hadn't been encountered before. Prior to this, it was known that CAMP levels were increased by vitamin D.

Discovery of an alternative mechanism to influence or raise CAMP levels is of scientific interest and could open new research avenues in nutrition and pharmacology, scientists said.

Turmeric is a flavorful, orange-yellow spice and an important ingredient in many curries, commonly found in Indian, South Asian and Middle Eastern cuisine. It has also been used for 2,500 years as a medicinal compound in the Ayurvedic system of medicine in India -- not to mention being part of some religious and wedding ceremonies. In India, turmeric is treated with reverence.

The newest findings were made by researchers in the Linus Pauling Institute at OSU and published in the Journal of Nutritional Biochemistry, in collaboration with scientists from the University of Copenhagen in Denmark. The work was supported by the National Institutes of Health.

"This research points to a new avenue for regulating CAMP gene expression," said Adrian Gombart, an associate professor of biochemistry and biophysics in the Linus Pauling Institute. "It's interesting and somewhat surprising that curcumin can do that, and could provide another tool to develop medical therapies."

The impact of curcumin in this role is not nearly as potent as that of vitamin D, Gombart said, but could nonetheless have physiologic value. Curcumin has also been studied for its anti-inflammatory and antioxidant properties.

"Curcumin, as part of turmeric, is generally consumed in the diet at fairly low levels," Gombart said. "However, it's possible that sustained consumption over time may be healthy and help protect against infection, especially in the stomach and intestinal tract."

In this study, Chunxiao Guo, a graduate student, and Gombart looked at the potential of both curcumin and omega-3 fatty acids to increase expression of the CAMP gene. They found no particular value with the omega-3 fatty acids for this purpose, but curcumin did have a clear effect. It caused levels of CAMP to almost triple.

There has been intense scientific interest in the vitamin D receptor in recent years because of potential therapeutic benefits in treating infection, cancer, psoriasis and other diseases, the researchers noted in their report. An alternative way to elicit a related biological response could be significant and merits additional research, they said.

Read more at Science Daily

Oldest Jewish Archaeological Evidence On the Iberian Peninsula

Archaeologists of the Friedrich Schiller University Jena (Germany) found some of the oldest archaeological evidence so far of Jewish culture on the Iberian Peninsula at an excavation site in the south of Portugal, close to the city of Silves (Algarve). On a marble plate, measuring 40 by 60 centimetres, the name "Yehiel" can be read, followed by further letters which have not yet been deciphered. The Jena Archaeologists believe that the new discovery might be a tomb slab. Antlers, which were found very close to the tomb slab in the rubble gave a clue to the age determination.

"The organic material of the antlers could be dated by radiocarbon analysis with certainty to about 390 AD," excavation leader Dr. Dennis Graen of the Jena University explains. "Therefore we have a so-called 'terminus ante quem' for the inscription, as it must have been created before it got mixed in with the rubble with the antlers."

The earliest archaeological evidence of Jewish inhabitants in the region of modern-day Portugal has so far also been a tomb slab with a Latin inscription and an image of a menorah -- a seven-armed chandelier -- from 482 AD. The earliest Hebrew inscriptions known until now date from the 6th or 7th Century AD.

For three years the team of the University Jena has been excavating a Roman villa in Portugal, discovered some years ago by Jorge Correia, archaeologist of the Silves council, during an archaeological survey near the village of São Bartolomeu de Messines (Silves). The project was aiming at finding out how and what the inhabitants of the hinterland of the Roman province of Lusitania lived off. While the Portuguese coast region has been explored very well, there is very little knowledge about those regions. The new discovery poses further conundrums. "We were actually hoping for a Latin inscription when we turned round the excavated tomb slab," Henning Wabersich, a member of the excavation reports. After all, no inscriptions have been found so far and nothing was known about the identity of the inhabitants of the enclosure.

Only after long research the Jena Archaeologists found out which language they were exactly dealing with, as the inscription was not cut with particular care. "While we were looking for experts who could help with deciphering the inscription between Jena and Jerusalem, the crucial clue came from Spain" Dennis Graen says. "Jordi Casanovas Miró from the Museu Nacional d'Art de Catalunya in Barcelona -- a well-known expert for Hebrew inscriptions on the Iberian Peninsula -- is sure that the Jewish name "Yehiel" can be read, -- a name that is already mentioned in the Bible." Not only is the early date exceptional in this case, but also the place of the discovery: Never before have Jewish discoveries been made in a Roman villa, the Jena Archaelogist explains.

In the Roman Empire at that time Jews usually wrote in Latin, as they feared oppressive measures. Hebrew, as on the re-discovered marble plate, only came back into use after the decline of the Roman supremacy, respectively in the following time of migration of peoples from the 6th or 7th century AD. "We were also most surprised that we found traces of Romans -- romanised Lusitanians in this case -- and Jews living together in a rural area of all things," Dennis Graen says. "We assumed that something like this would have been much more likely in a city."

Information about the Jewish population in the region in general was mostly passed down by scriptures. "During the ecclesiastical council in the Spanish town Elvira about 300 AD rules of conduct between Jews and Christians were issued. This indicates that at this time there must have been a relatively large number of Jews on the Iberian Peninsula already," Dennis Graen explains -- but archaeological evidence had been missing so far. "We knew that there was a Jewish community in the Middle Ages not far from our excavation site in the town of Silves. It existed until the expulsion of the Jews in the year 1497."

Read more at Science Daily