Volcanoes on Jupiter's Moon Io Are All Wrong

The hundreds of volcanoes on Jupiter's moon Io aren't where they're supposed to be, scientists say.

Io's major volcanic activity is concentrated 30 to 60 degrees farther east than models of its internal heat profile predict, a recent study reports, suggesting that the exotic, volcanic Jupiter moon Io is even more mysterious than researchers had previously thought.

"The unexpected eastward offset of the volcano locations is a clue that something is missing in our understanding of Io," study lead author Christopher Hamilton, of the University of Maryland, said in a statement. "In a way, that's our most important result. Our understanding of tidal heat production and its relationship to surface volcanism is incomplete."

Io is the most volcanic body in the solar system, boasting activity 25 times that of Earth. Some of Io's volcanoes blast plumes of sulfur and other material 250 miles (400 kilometers) above the moon, which is completely resurfaced every million years or so. On Thursday (April 4), NASA released a video of Io's volcano plumes based on five images snapped by the agency's Pluto-bound New Horizons spacecraft in March 2007.

This intense activity is ultimately generated by gravitational tugs from Jupiter, with an assist from the nearby moons Europa and Ganymede.

Io completes two orbits for every one that Europa makes, and four for every one of Ganymede's laps. As a result of this regular timing, Europa and Ganymede have pulled the orbit of Io into an oval, with explosive consequences for the 2,260-mile-wide (3,640 km) moon.

As Io moves closer to Jupiter, the planet's powerful gravity pulls hard on the moon, deforming it. This force decreases as Io retreats, and the moon bounces back. This cycle of flexing creates friction in Io's interior, which in turn generates enormous amounts of volcano-driving tidal heat.

Common sense suggests that Io's volcanoes would be located above the spots with the most dramatic internal heating. But Hamilton and his colleagues found that the volcanoes are significantly farther to the east than expected.

They reached this surprising conclusion after studying data gathered by several ground-based telescopes and a number of spacecraft, including NASA's Voyager and Galileo probes, then comparing this information to a detailed geologic map of Io that scientists put together last year.

What's causing the disconnect between expected and observed volcano locations remains a mystery. It's possible that Io is rotating faster that scientists think, researchers said. Or models of Io's tidal heating may be missing some components, such as the complications caused by an underground magma ocean.

"Our analysis supports a global subsurface magma ocean scenario as one possible explanation for the offset between predicted and observed volcano locations on Io," Hamilton said. "However, Io's magma ocean would not be like the oceans on Earth. Instead of being a completely fluid layer, Io's magma ocean would probably be more like a sponge with at least 20 percent silicate melt within a matrix of slowly deformable rock."

Read more at Discovery News

'Ice fish' Bleeds Clear Blood

The deep oceans have yielded many mysteries that have puzzled people for centuries, from the giant squid to huge jellyfish that look like UFOs. To that list add a fish with totally transparent blood.

The Ocellated Ice Fish lives in the freezing waters of the Antarctic Ocean, where it manages to keep its body doing all the things that other fish do, but with blood that is absolutely clear, researchers said.

The reason, say experts at Tokyo Sea Life Park, is that the Ocellated Ice Fish has no hemoglobin, making it unique among vertebrates the world over.

Hemoglobin is the protein found in every other animal with bones. It is what makes blood red and is the agent that carries oxygen around the body.

The fish, which has no scales, is a prize catch for the aquarium, the only place on the planet that has the curious specimen in captivity.

Satoshi Tada, an education specialist at the center, said very little is known about the fish, which was brought back to Japan by krill fishermen.

"Luckily, we have a male and a female, and they spawned in January," he said, adding that having more examples to study might help scientists unlock some of the fish's secrets.

Researchers believe the fish can live without hemoglobin because it has a large heart and uses blood plasma to circulate oxygen throughout its body.

Its skin is also thought to be able to absorb oxygen from the rich waters of the Antarctic, where it is found at depths of up to a kilometer(3,300 feet).

Read more at Discovery News

How Life May Have First Emerged On Earth: Foldable Proteins in a High-Salt Environment

A structural biologist at the Florida State University College of Medicine has made discoveries that could lead scientists a step closer to understanding how life first emerged on Earth billions of years ago.

Professor Michael Blaber and his team produced data supporting the idea that 10 amino acids believed to exist on Earth around 4 billion years ago were capable of forming foldable proteins in a high-salt (halophile) environment. Such proteins would have been capable of providing metabolic activity for the first living organisms to emerge on the planet between 3.5 and 3.9 billion years ago.

The results of Blaber's three-year study, which was built around investigative techniques that took more than 17 years to develop, are published in the journal Proceedings of the National Academy of Sciences.

The first living organisms would have been microscopic, cell-like organizations capable of replicating and adapting to environmental conditions -- a humble beginning to life on Earth.

"The current paradigm on the emergence of life is that RNA came first and in a high-temperature environment," Blaber said. "The data we are generating are much more in favor of a protein-first view in a halophile environment."

The widely accepted view among scientists is that RNA, found in all living cells, would have likely represented the first molecules of life, hypothesizing an "RNA-first" view of the origin of living systems from non-living molecules. Blaber's results indicate that the set of amino acids produced by simple chemical processes contains the requisite information to produce complex folded proteins, which supports an opposing "protein-first" view.

Another prevailing view holds that a high-temperature (thermophile) environment, such as deep-ocean thermal vents, may have been the breeding ground for the origin of life. "The halophile, or salt-loving, environment has typically been considered one that life adapted into, not started in," Blaber said. "Our study of the prebiotic amino acids and protein design and folding suggests the opposite."

Without the ability to fold, proteins would not be able to form the precise structures essential for functions that sustain life as we know it. Folding allows proteins to take on a globular shape through which they can interact with other proteins, perform specific chemical reactions, and adapt to enable organisms to exploit a given environment.

"There are numerous niches that life can evolve into," Blaber said. "For example, extremophiles are organisms that exist in high temperatures, high acidity, extreme cold, extreme pressure and extreme salt and so on. For life to exist in such environments it is essential that proteins are able to adapt in those conditions. In other words, they have to be able to fold."

Comet and meteorite fragments, like those that recently struck in the Urals region of Russia, have provided evidence regarding the arrival of amino acids on Earth. Such fragments predate Earth and would have been responsible for delivering a set of 10 prebiotic (before life) amino acids, whose origins are in the formation of our solar system.

Today the human body uses 20 common amino acids to make all its proteins. Ten of those emerged through biosynthetic pathways -- the way living systems evolve. Ten -- the prebiotic set -- can be made by chemical reactions without requiring any living system or biosynthetic pathway.

Scientific evidence exists to support many elements in theories of abiogenesis (the emergence of life), including the time frame (around 3.5 to 3.9 billion years ago) and the conditions on Earth and in its atmosphere at that time. Earth would have been made up of volcanic land masses (the beginning of the formation of continents), salty oceans and fresh-water ponds, along with a hot (around 80 degrees Celsius) and steamy atmosphere comprising carbon dioxide and nitrogen. Oxygen would have come later as a by-product of green plant life and bacteria that emerged.

Using a technique called top-down symmetric deconstruction, Blaber's lab has been able to identify small peptide building blocks capable of spontaneous assembly into specific and complex protein architectures. His recent work explored whether such building blocks can be composed of only the 10 prebiotic amino acids and still fold.

His team has achieved foldability in proteins down to 12 amino acids -- about 80 percent of the way to proving his hypothesis.

Read more at Science Daily

Meet the Tarantula as Big as Your Face

It's big, it's hairy, and it's venomous.

The newest spider to give arachnophobes the willies, a tarantula named Poecilotheria rajaei has been discovered on the island nation of Sri Lanka.

With a leg span of 8 inches (20 centimeters) and enough venom to kill mice, lizards, small birds and snakes, according to Sky News, the crawler is covered in subtle markings of gray, pink and daffodil yellow.

"It can be quite attractive, unless spiders freak you out," Peter Kirk, editor of the British Tarantula Society journal, told the New York Daily News.

Even the scientists studying the spiders admit to being a little freaked out by its size: "It was slightly smaller than the size of the plate we have dinner on," Ranil Nanayakkara, co-founder of Sri Lanka’s Biodiversity Education and Research, told the Daily News.

Tarantulas have been the subject of considerable study lately: Researchers are still trying to determine how or if tarantulas use silk from the spigots on their feet. And in 2012, a scientist reported discovering nine species of colorful Amazonian tarantulas in Brazil.

The newest tarantula, as part of the Poecilotheria genus of arachnids (sometimes called "Pokies" or tiger spiders), is a tree-dwelling spider. All the Pokies, known for being colorful, fast and venomous, are found only in India and Sri Lanka, Wired reports. [Photos: The World's Creepiest Spiders]

"They are quite rare," Nanayakkara told Wired. "They prefer well-established old trees, but due to deforestation the number have dwindled, and due to lack of suitable habitat they enter old buildings."

The spider was first seen in 2009 after the discovery of a dead male specimen, on which scientists noticed a unique pink abdominal band.

"In order to establish if this really was a new species to Sri Lanka and to the world, the authors carried out intensive and extensive surveys in the northern part of Sri Lanka to establish the distribution and ecology of this new species," the scientists write in the British Tarantula Society journal.

"But what was lacking was a female or any other specimen of the same type. Days of extensive searching in every tree hole and bark peel were rewarded with a female and to our satisfaction several juveniles too."

It's not yet known exactly how rare the newly discovered tarantula is, but there's some concern that habitat destruction is causing their number to dwindle. Additionally, northern Sri Lanka, where the spider was found, has been wracked by political violence in recent years.

Read more at Discovery News

Tech May Be Whistled Language's Demise

In some remote parts of Oaxaca, Mexico, local men can carry on whole conversations across long distances of the Sierra Madre del Sur mountain range. Rather than shouting across the rugged terrain, they make themselves heard though a complex series of whistles.

Researchers suspect the whistled talk could be as old as the earliest languages. But while some young people in the Oaxacan Cuicatlán District can still speak the language, the days of the unique form of communication is likely numbered.

Modern innovations, such as cell phones and walkie-talkies, are now more commonly used for long-distance communication. And the whistled language's roots -- the Chinantec spoken language -- is also itself threatened by the more prevalent usage of Spanish. A recent research project, "Documenting Whistled Speech Among Chinantecans," aimed to study the language before it's too late.

"Whistled speech made the local Chinantec language portable across canyons, fields and along the steep slopes where the village houses cling to the hillsides, making travel physically challenging," project leader Mark Sicoli told Discovery News.

"Such rugged, inaccessible landscapes are the types of terrain where whistled versions of spoken languages have been developed in places as far from Mexico as the Canary Islands, Africa, Greece and Turkey, New Guinea, and St. Lawrence Island in the Bering Sea," added Sicoli, who is an assistant professor in Georgetown University’s Department of Linguistics.

Sicoli and his team traveled to the region in order to document and archive examples of whistled conversations transcribed in written Chinantec and translated to Spanish and English.

Sicoli also developed a map navigational task, which asked one speaker to whistle directions to a second speaker to follow on a map. The successful use of the whistling demonstrated just how effective this unique form of speech can be.

Most Chinantec words turned out to have a whistled counterpart. The archive, for example, includes whistles that translate to sentences like: "Do you have any edible fungus growing in your corn field?" "Where are you going?" "What are you going to do at noon today?" and "I'm going to eat tacos for dinner tonight."

"Due to its acoustic range, whistling can substitute for standard vocalized speech over both short and long distances, alleviating pressure on vocal chords and overcoming the difficulties of communicating long distances over difficult terrain," Sicoli explained.

A short-distance whistled "conversation" is more like regular mouth-puckered whistling, while long-distance communications may involve the sports stadium-type finger in the mouth whistling. The researchers found that the language is spoken mainly by men, although women often understand the whistled language, even if they don't speak it.

Daniel Everett, a professor of global studies and sociology at Bentley University, pointed out that "many of the world's languages may be whistled. English's limitation to consonants and vowels is a restriction to one channel of discourse, while whistled languages illustrate that human languages need not be so constrained."

Everett added, "When we study languages like these, we learn that the perimeters of human capability are more encompassing and contain more richness than we would have otherwise known."

It is unclear when whistled speech first emerged.

"Hypothetically, whistled speech could be as old as the earliest languages," said Sicoli, adding that it could even have been a component of proto-language -- the precursor of human language used by earlier hominid species.

"Whistling itself is something that has been self-learned by at least one ape," he added. "Bonnie, a female orangutan at the National Zoo in DC, taught herself to whistle for what seems to simply be the pleasure of it. What Bonnie shows is that, anatomically, whistling would have been in the range of potential sound-making behavior of archaic Homo sapiens, including Neanderthal and earlier hominids like Homo erectus and Australopithecines."

Read more at Discovery News

Hubble Spots the Most Distant Type Ia Supernova Ever

Astronomers working on a multi-year program with the Hubble Space Telescope have announced the discovery of the most distant Type Ia supernova ever observed, a stellar explosion that occurred over 10 billion years ago — breaking the previous record by nearly a billion years.

What’s especially important is the kind of supernova that’s been discovered. Designated SN UDS10Wil (and nicknamed SN Wilson after the 28th president of the United States) this distant detonation is a Type Ia — that’s “one-A” — supernova, the garden variety of which are used as standard candles by scientists to measure distances across the universe.

Calculating distance in intergalactic space from here on Earth isn’t easy. So in order to figure out how far away galaxies are, astronomers have learned to use the light from Type Ia supernovae, which briefly — but consistently — shine with a brilliance equal to 5 billion suns.

This method has proven useful for distances beyond our galaxy (they use different ways to measure space within the Milky Way) despite the fact that it’s not known exactly what kinds of stars create Type Ia supernovae in the first place. While it’s generally accepted that they are the result of the accumulation of matter between two stars in a binary pair until a critical mass is reached and a brilliant stellar explosion occurs, two different scenarios are currently on the table: one, that the pair consists of a white dwarf pulling matter from a swollen red giant partner, and two, the stars are both white dwarfs locked in orbit with each other, getting closer and closer until they eventually merge together and… boom. Supernova.

The discovery of supernova SN Wilson helps lend credence to the latter, if only because it’s so far removed from the previous record-holders. The steep drop-off in Type Ia supernovae between 7.5 and 10 billion years ago found by the three-year Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) and the Cluster Lensing and Supernova Survey with Hubble (CLASH) surveys indicates the sheer amount of time needed for two white dwarfs — which are the final life stages of stars like our sun — to form within binary pairs and eventually merge.

“This new result is a really exciting step forward in our study of supernovae and the distant universe,” said team member Jens Hjorth of the Dark Cosmology Centre at the University of Copenhagen. “We can begin to explore and understand the stars that cause these violent explosions.”

Read more at Discovery News

3-D Printer Can Build Synthetic Tissues

A custom-built programmable 3D printer can create materials with several of the properties of living tissues, Oxford University scientists have demonstrated.

The new type of material consists of thousands of connected water droplets, encapsulated within lipid films, which can perform some of the functions of the cells inside our bodies.

These printed 'droplet networks' could be the building blocks of a new kind of technology for delivering drugs to places where they are needed and potentially one day replacing or interfacing with damaged human tissues. Because droplet networks are entirely synthetic, have no genome and do not replicate, they avoid some of the problems associated with other approaches to creating artificial tissues -- such as those that use stem cells.

The team report their findings in this week's Science.

'We aren't trying to make materials that faithfully resemble tissues but rather structures that can carry out the functions of tissues,' said Professor Hagan Bayley of Oxford University's Department of Chemistry, who led the research. 'We've shown that it is possible to create networks of tens of thousands connected droplets. The droplets can be printed with protein pores to form pathways through the network that mimic nerves and are able to transmit electrical signals from one side of a network to the other.'

Each droplet is an aqueous compartment about 50 microns in diameter. Although this is around five times larger than living cells the researchers believe there is no reason why they could not be made smaller. The networks remain stable for weeks.

'Conventional 3D printers aren't up to the job of creating these droplet networks, so we custom built one in our Oxford lab to do it,' said Professor Bayley. 'At the moment we've created networks of up to 35,000 droplets but the size of network we can make is really only limited by time and money. For our experiments we used two different types of droplet, but there's no reason why you couldn't use 50 or more different kinds.'

The unique 3D printer was built by Gabriel Villar, a DPhil student in Professor Bayley's group and the lead author of the paper.

The droplet networks can be designed to fold themselves into different shapes after printing -- so, for example, a flat shape that resembles the petals of a flower is 'programmed' to fold itself into a hollow ball, which cannot be obtained by direct printing. The folding, which resembles muscle movement, is powered by osmolarity differences that generate water transfer between droplets.

Read more at Science Daily

An Ancient Biosonar Sheds New Light On the Evolution of Echolocation in Toothed Whales

Some 30 million years ago, Ganges river dolphins diverged from other toothed whales, making them one of the oldest species of aquatic mammals that use echolocation, or biosonar, to navigate and find food. This also makes them ideal subjects for scientists working to understand the evolution of echolocation among toothed whales.

New research, led by Frants Havmand Jensen, a Danish Council for Independent Research / Natural Sciences postdoctoral fellow at Woods Hole Oceanographic Institution, shows that freshwater dolphins produce echolocation signals at very low sound intensities compared to marine dolphins, and that Ganges river dolphins echolocate at surprisingly low sound frequencies. The study, "Clicking in shallow rivers," was published in the journal PLOS ONE.

"Ganges River dolphins are one of the most ancient evolutionary branches of toothed whales," says Jensen. "We believe our findings help explain the differences in echolocation between freshwater and marine dolphins. Our findings imply that the sound intensity and frequency of Ganges river dolphin may have been closer to the 'starting point' from which marine dolphins gradually evolved their high-frequent, powerful biosonar."

The scientists believe these differences evolved due to differences in freshwater and marine environments and the location and distribution of prey in those environments.

A complex, underwater environment

To sustain themselves, river dolphins must find their food, often small fish or crustaceans, in highly turbid water where visibility seldom exceeds a few inches. Like their marine relatives, they manage this using echolocation: They continuously emit sound pulses into the environment and listen for the faint echoes reflected off obstacles while paying special attention to the small details in the echoes that might signify a possible meal.

The environment that freshwater dolphins operate in poses very different challenges to a biosonar than the vast expanses of the sea where most dolphins later evolved. "Dolphins that range through the open ocean often feed on patchily distributed prey, such as schools of fish," Jensen says. "They have had a large advantage from evolving an intense biosonar that would help them detect prey over long distances, but we have little idea of how the complex river habitats of freshwater dolphins shape their biosonar signals."

Shy study animals with a surprisingly deep voice

To answer that question, the researchers recorded the echolocation signals of two species of toothed whales inhabiting the same mangrove forest in the southern part of Bangladesh: The Ganges river dolphin, an exclusively riverine species that is actually not part of the dolphin family but rather the Platanistidae family, and the Irrawaddy, a freshwater toothed whale from the dolphin family that lives in both coastal and riverine habitats.

Surprisingly, the echolocation signals turned out to be much less intense than those employed by marine dolphins of similar size and it seemed that the freshwater dolphins were looking for prey at much shorter distances. From this, the researchers surmise that both the dolphin species and the river dolphin were echolocating at short range due to the complex and circuitous river system that they were foraging in.

While both Irawaddy and Ganges river dolphin produced lower intensity biosonar, the Ganges river dolphin had an unexpectedly low frequency biosonar, nearly half as high as expected if this species had been a marine dolphin.

"It is very surprising to see these animals produce such low-frequent biosonar sounds. We are talking about a small toothed whale the size of a porpoise producing sounds that would be more typical for a killer whale or a large pilot whale," says Professor Peter Teglberg Madsen from Aarhus University in Denmark, an expert on toothed whale biosonar and co-author of the study.

A new perspective on the evolution of biosonar

The study suggests that echolocation in toothed whales initially evolved as a short, broadband and low-frequent click. As dolphins and other toothed whales evolved in the open ocean, the need to detect schools of fish or other prey items quickly favored a long-distance biosonar system. As animals gradually evolved to produce and to hear higher sound frequencies, the biosonar beam became more focused and the toothed whales were able to detect prey further away.

However, the Ganges river dolphin separated from other toothed whales early throughout this evolutionary process, adapting to a life in shallow, winding river systems where a high-frequency, long-distance sonar system may have been less important than other factors such as high maneuverability or the flexible neck that helps these animals capture prey at close range or hiding within mangrove roots or similar obstructions.

Read more at Science Daily

Cat Paw Prints Found on 15th-Century Manuscript

A Medieval cat literally walked through history, leaving its paw prints on a 15th-century Croatian manuscript, according to an historian.

Emir Filipović, a research assistant at the University of Sarajevo, happened to be thumbing through the manuscript when he noticed the inky paw prints.

“It’s not very often that a researcher can come across curious things while sifting through monotonous and dull archival registers,” Filipović told National Geographic.

He shared the above image on Twitter, and news about the find spread.

The manuscript’s text had nothing to do with cats, but instead was a rather dry Republic of Dubrovnik letter to traders and nobles.

“The document on which prints were made dates from March 11, 1445,” Filipović told BalkanInsight. “The prints were most likely made while the document was being made, or some time then…but the possibility that they were made later cannot be excluded.”

He added, “While the writer was writing the document a cat probably passed by him and since the paint was near the book…the cat spilled it, dipped his paws in it and passed over the document and thus left its trace in history.”

Based on the prints, it looks like the cat marched on the manuscript, coming from the left, and then made a left turn on the right page before stepping off. It was just a mundane, typical house-cat moment, but one that might have been preserved for hundreds of years.

Read more at Discovery News

Kepler Watches White Dwarf Warp Spacetime

The Kepler space telescope’s prime objective is to hunt for small worlds orbiting distant stars, but that doesn’t mean it’s not going to detect some extreme relativistic phenomena along the way.

While monitoring a red dwarf star — designated KOI-256 — astronomers detected a dip in starlight in the Kepler data. The NASA space telescope is constantly on the lookout for these dips as they can be an indicator of an extrasolar planet passing in front of the star’s disk. This event is known as a “transit” and Kepler has the unprecedented sensitivity to detect sub-Earth-sized worlds drift in front of their host stars.

When a transit was detected in the KOI-256 system, researchers led by Caltech’s Phil Muirhead thought they’d just witnessed a massive planet orbiting the star. However, something was very strange about this particular transit.

“We saw what appeared to be huge dips in the light from the star, and suspected it was from a giant planet, roughly the size of Jupiter, passing in front,” said Muirhead.

Using the ground-based Palomar Observatory in California, Muirhead’s team applied another exoplanet-hunting technique to KOI-256. The “radial velocity method” can detect worlds in orbit around other stars through the careful analysis of the spectrum of starlight. If an exoplanet is in orbit, the mass of the world will gravitationally “tug” on the host star. This tugging creates a slight wobble, generating a red- and blue-shifting of light; a tell-tail sign that a planet is there.

Radial velocity measurements of KOI-256, however, revealed that something else was there — and it certainly wasn’t an exoplanet. The star was found to be wobbling “like a spinning top” meaning something way more massive is in orbit — a compact white dwarf star, the stellar husk of a burned-out star.

Although red dwarfs are small, white dwarfs are even smaller, but very, very dense. The white dwarf in the KOI-256 binary is about the size of Earth and yet packs the mass of the sun. “It’s so hefty that the red dwarf, though larger in physical size, is circling around the white dwarf,” added Muirhead.

Most of the stars in our galaxy are binary stars; two stars in a tight cosmic dance is not a rarity.

With the help of another NASA space observatory, the Galaxy Evolution Explorer (GALEX), which analyzes the ultraviolet light of the stars in Kepler’s field of view, the researchers noticed that as the white dwarf passed behind the red dwarf, the starlight would dim, but when the white dwarf passed in front, the light would be slightly brighter than expected. This is counter-intuitive to how transits work, but KOI-256 is anything but intuitive.

As the white dwarf passed in front of the red dwarf, its extreme gravitational field was causing spacetime to bend, focusing the light from the red dwarf, enhancing the starlight. As the white dwarf passed behind the red dwarf, there would be no gravitational disruption of starlight and therefore no starlight enhancement. This finding will be published on April 20 in the Astrophysical Journal.

“Only Kepler could detect this tiny, tiny effect,” said Doug Hudgins, Kepler program scientist at NASA Headquarters, Washington. “But with this detection, we are witnessing Einstein’s theory of general relativity at play in a far-flung star system.”

Read more at Discovery News

Rocky Mountains Originated from Previously Unknown Oceanic Plate

The mountain ranges of the North American Cordillera are made up of dozens of distinct crustal blocks. A new study clarifies their mode of origin and identifies a previously unknown oceanic plate that contributed to their assembly.

The extensive area of elevated topography that dominates the Western reaches of North America is exceptionally broad, encompassing the coastal ranges, the Rocky Mountains and the high plateaus in between. In fact, this mountain belt consists of dozens of crustal blocks of varying age and origin, which have been welded onto the American continent over the past 200 million years. "How these blocks arrived in North America has long been a puzzle," says LMU geophysicist Karin Sigloch, who has now taken a closer look at the problem, in collaboration with the Canadian geologist Mitchell Mihalynuk.

Collisions and continental growth

One popular model for the accretion process postulates that a huge oceanic plate -- the Farallon Plate -- acted as a conveyor belt to sweep crustal fragments eastwards to the margin of American Plate, to which they were attached as the denser Farallon Plate was subducted under it. However, this scenario is at variance with several geological findings, and does not explain why the same phenomenon is not observed on the west coast of South America, the classical case of subduction of oceanic crust beneath a continental plate. The precise source of the crustal blocks themselves has also remained enigmatic, although geological studies suggest that they derive from several groups of volcanic islands. "The geological strata in North America have been highly deformed over the course of time, and are extremely difficult to interpret, so these findings have not been followed up," says Sigloch.

Sigloch and Mihalynuk have now succeeded in assembling a comprehensive picture of the accretion process by incorporating geophysical findings obtained by seismic tomography. This technique makes it possible to probe the geophysical structure of Earth's interior down to the level of the lower mantle by analyzing the propagation velocities of seismic waves. The method can image the remnants of ancient tectonic plates at great depths, ocean floor that subducted, i.e., disappeared from the surface and sank back into the mantle, long time ago.

Intra-oceanic subduction of the Farallon Plate

Most surprisingly, the new data suggest that the Farallon Plate was far smaller than had been assumed, and underwent subduction well to the west of what was then the continental margin of North America. Instead it collided with, and subducted under, an intervening and previously unrecognized oceanic plate. Sigloch and Mihalynuk were able to locate the remnants of several deep-sea trenches that mark subduction sites at which oceanic plates plunge at a steep angle into the mantle and are drawn almost vertically into its depths. "The volcanic activity that accompanies the subduction process will have generated lots of new crustal material, which emerged in the form of island arcs along the line of the trenches, and provided the material for the crustal blocks," Sigloch explains.

Read more at Science Daily

Chimps: Ability to 'Think About Thinking' Not Limited to Humans

Humans' closest animal relatives, chimpanzees, have the ability to "think about thinking" -- what is called "metacognition," according to new research by scientists at Georgia State University and the University at Buffalo.

Michael J. Beran and Bonnie M. Perdue of the Georgia State Language Research Center (LRC) and J. David Smith of the University at Buffalo conducted the research, published in the journal Psychological Science of the Association for Psychological Science.

"The demonstration of metacognition in nonhuman primates has important implications regarding the emergence of self-reflective mind during humans' cognitive evolution," the research team noted.

Metacognition is the ability to recognize one's own cognitive states. For example, a game show contestant must make the decision to "phone a friend" or risk it all, dependent on how confident he or she is in knowing the answer.

"There has been an intense debate in the scientific literature in recent years over whether metacognition is unique to humans," Beran said.

Chimpanzees at Georgia State's LRC have been trained to use a language-like system of symbols to name things, giving researchers a unique way to query animals about their states of knowing or not knowing.

In the experiment, researchers tested the chimpanzees on a task that required them to use symbols to name what food was hidden in a location. If a piece of banana was hidden, the chimpanzees would report that fact and gain the food by touching the symbol for banana on their symbol keyboards.

But then, the researchers provided chimpanzees either with complete or incomplete information about the identity of the food rewards.

In some cases, the chimpanzees had already seen what item was available in the hidden location and could immediately name it by touching the correct symbol without going to look at the item in the hidden location to see what it was.

In other cases, the chimpanzees could not know what food item was in the hidden location, because either they had not seen any food yet on that trial, or because even if they had seen a food item, it may not have been the one moved to the hidden location.

In those cases, they should have first gone to look in the hidden location before trying to name any food.

In the end, chimpanzees named items immediately and directly when they knew what was there, but they sought out more information before naming when they did not already know.

Read more at Science Daily

Maya Blue Paint Recipe Deciphered

The ancient Maya used a vivid, remarkably durable blue paint to cover their palace walls, codices, pottery and maybe even the bodies of human sacrifices who were thrown to their deaths down sacred wells. Now a group of chemists claim to have cracked the recipe of Maya Blue.

Scientists have long known the two chief ingredients of the intense blue pigment: indigo, a plant dye that's used today to color denim; and palygorskite, a type of clay. But how the Maya cooked up the unfading paint remained a mystery. Now Spanish researchers report that they found traces of another pigment in Maya Blue, which they say gives clues about how the color was made.

"We detected a second pigment in the samples, dehydroindigo, which must have formed through oxidation of the indigo when it underwent exposure to the heat that is required to prepare Maya Blue," Antonio Doménech, a researcher from the University of Valencia, said in a statement.

"Indigo is blue and dehydroindigo is yellow, therefore the presence of both pigments in variable proportions would justify the more or less greenish tone of Maya Blue," Doménech explained. "It is possible that the Maya knew how to obtain the desired hue by varying the preparation temperature, for example heating the mixture for more or less time or adding more of less wood to the fire."

American researchers in 2008 claimed that copal resin, which was used for incense, may have been the third secret ingredient for Maya Blue. Their research was based on a study of a bowl that had traces of the pigment and was used to burn incense. But Doménech's team didn't buy those findings.

"The bowl contained Maya Blue mixed with copal incense, so the simplified conclusion was that it was only prepared by warming incense," Doménech said in a statement.

The Spanish researchers say they are now investigating the chemical bonds that bind the paint's organic component (indigo) to the inorganic component (clay), which is key to Maya Blue's resilience.

Read more at Discovery News

Dark Matter Found? Orbital Experiment Detects Hints

A $2 billion particle detector attached to the International Space Station has detected the potential signature of dark matter annihilation in the Cosmos, scientists have announced today.

The Alpha Magnetic Spectrometer (AMS) was attached to the space station in May 2011 by space shuttle Endeavour — the second-to last shuttle mission to the orbital outpost. Since then, the AMS has been detecting electrons and positrons (the electron’s anti-particle) originating from deep space and assessing their energies. By doing a tally of electrons and positrons, physicists hope the AMS will help to answer one of the most enduring mysteries in science: Does dark matter exist?

And today, it looks like the answer is a cautious, yet exciting, yes.

Results from the AMS have been highly anticipated, and in a special announcement to be made at 1:30 p.m. EDT (6:30 p.m. GMT) today (April 3) the first results from billions of particle detections will be detailed. The details of the research have also been revealed by a CERN announcement ahead of the study being published in the journal Physical Review Letters.

Around 400,000 positron detections have been confirmed in this first batch of data — positrons that are of energies consistent with the signature of dark matter annihilation.

Dark matter is thought to make up 80 percent of all matter in the Universe, the rest is “baryonic matter” — i.e. the stuff we’re made of. But the vast majority of matter is locked in an invisible component of matter. As the moniker suggests, dark matter is dark; it doesn’t interact with electromagnetic radiation. However, dark matter still carries mass that has a gravitational effect on space-time and through indirect means we can detect its gravitational presence.

Theory suggests that Weakly-Interacting Massive Particles (WIMPs) may be a part of non-baryonic matter, bulking up the mass of the Universe. WIMPs are their own anti-particles; when two WIMPs collide, they annihilate and produce positrons and electrons (and energy). But for physicists to confirm WIMP annihilation does occur, the positrons need to have a specific energy signature.

Positrons with energies of 0.5 GeV to 250 GeV have been recorded by the AMS — the largest collection of antimatter particles recorded in space. “The positron fraction increases from 10 GeV to 250 GeV, with the data showing the slope of the increase reducing by an order of magnitude over the range 20-250 GeV,” writes the CERN release. This is consistent with the theory that WIMPs are out there, annihilating. And, apparently, these positrons are originating from all directions, bolstering the theory that dark matter permeates the whole Universe.

Other space-based experiments have seen clues of this dark matter signature, such as the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) instrument. But their measurements of the particle energy spectra have been too “coarse”; the AMS can produce a very refined spectrum of positron energies, allowing scientists an unprecedented high-resolution view of positron energies.

But this is by no means proof of WIMPs and a positive identification of dark matter annihilation. Pulsars — rapidly-spinning neutron stars — could also be generating this positron signal, so further work needs to be done.

“As the most precise measurement of the cosmic ray positron flux to date, these results show clearly the power and capabilities of the AMS detector,” said Nobel laureate Samuel Ting, of the Massachusetts Institute of Technology (MIT) who leads the international AMS team, in the CERN announcement. “Over the coming months, AMS will be able to tell us conclusively whether these positrons are a signal for dark matter, or whether they have some other origin.”

Read more at Discovery News

Eating Fish Linked to Longer Life

People age 65 and older who eat fish may live an average of two years longer than people who do not consume the omega-3 fatty acids found mainly in seafood, a US study suggested on Monday.

People with higher levels of omega-3 fatty acids also had an overall risk of dying that was 27 percent lower, and a risk of dying from heart disease that was 35 percent lower than counterparts who had lower blood levels, said the study.

The research was led by scientists at the Harvard School of Public Health and was published in the Annals of Internal Medicine.

While other studies have demonstrated a link between omega-3 fatty acids and lower risk of heart disease, this research examined records of older people to determine any link between fish-eating and death risk.

Researchers scanned 16 years of data on about 2,700 US adults aged 65 or older. Those considered for the study were not taking fish oil supplements, to eliminate any confusion over the use of supplements or dietary differences.

Those with the highest blood levels of omega-3 fatty acids found mainly in fish like salmon, tuna, halibut, sardines, herring and mackerel, had the lowest risk of dying from any cause, and lived an average of 2.2 years longer than those with low levels.

Researchers identified docosahexaenoic acid (DHA) as most strongly related to lower risk of coronary heart disease death.

Eicosapentaenoic acid (EPA) was strongly linked to lower risk of nonfatal heart attack, and docosapentaenoic acid (DPA) was most strongly associated with lower risk of dying from a stroke.

The findings persisted after researchers adjusted for demographic, lifestyle and diet factors.

Read more at Discovery News

Trove of Neanderthal Bones Found in Greek Cave

A trove of Neanderthal fossils including bones of children and adults, discovered in a cave in Greece hints the area may have been a key crossroad for ancient humans, researchers say.

The timing of the fossils suggests Neanderthals and humans may have at least had the opportunity to interact, or cross paths, there, the researchers added.

Neanderthals are the closest extinct relatives of modern humans, apparently even occasionally interbreeding with our ancestors. Neanderthals entered Europe before modern humans did, and may have lasted there until about 35,000 years ago, although recent findings have called this date into question.

To learn more about the history of ancient humans, scientists have recently focused on Greece.

"Greece lies directly on the most likely route of dispersals of early modern humans and earlier hominins into Europe from Africa via the Near East," paleoanthropologist Katerina Harvati at the University of Tübingen in Germany told LiveScience. "It also lies at the heart of one of the three Mediterranean peninsulae of Europe, which acted as refugia for plant and animal species, including human populations, during glacial times — that is, areas where species and populations were able to survive during the worst climatic deteriorations."

"Until recently, very little was known about deep prehistory in Greece, chiefly because the archaeological research focus in the country has been on classical and other more recent periods," Harvati added.

Harvati and colleagues from Greece and France analyzed remains from a site known as Kalamakia, a cave stretching about 65 feet (20 meters) deep into limestone cliffs on the western coast of the Mani Peninsula on the mainland of Greece. They excavated the cave over the course of 13 years.

The archaeological deposits of the cave date back to between about 39,000 and 100,000 years ago to the Middle Paleolithic period. During the height of the ice age, the area still possessed a mild climate and supported a wide range of wildlife, including deer, wild boar, rabbits, elephants, weasels, foxes, wolves, leopards, bears, falcons, toads, vipers and tortoises.

In the cave, the researchers found tools such as scrapers made of flint, quartz and seashells. The stone tools were all shaped, or knapped, in a way typical of Neanderthal artifacts.

Now, the scientists reveal they discovered 14 specimens of child and adult human remains in the cave, including teeth, a small fragment of skull, a vertebra, and leg and foot bones with bite and gnaw marks on them. The teeth strongly appear to be Neanderthal, and judging by marks on the teeth, the ancient people apparently had a diet of meat and diverse plants.

"Kalamakia, together with the single human tooth from the nearby cave site of Lakonis, are the first Neanderthal remains to be identified from Greece," Harvati said. The discoveries are "confirmation of a thriving and long-standing Neanderthal population in the region."

These findings suggest "the fossil record from Greece potentially holds answers about the earliest dispersal of modern humans and earlier hominins into Europe, about possible late survival of Neanderthals and about one of the first instances where the two might have had the opportunity to interact," Harvati said.

Read more at Discovery News

Faint 'Red Arcs' Spotted Over Europe

Glowing red arcs invisible to the naked eye have now been detected high above most of Europe using advanced cameras pointed at the sky.

When streams of high-energy, charged particles come rushing from the sun to batter Earth, they cause what are called geomagnetic storms. These events are disruptions in the magnetosphere, the part of Earth's atmosphere dominated by the planet's magnetic field. The most dramatic effects of these storms are giant, bright auroras in Earth's polar regions, but the tempests result in other striking consequences as well, such as faintly glowing red arcs high up in the ionosphere. This is the electrically charged part of Earth's atmosphere, stretching from about 50 to 370 miles (85 to 600 kilometers) above the Earth.

The arcs give off a very specific wavelength of red light, but are too faint to see with the naked eye. They appear at lower latitudes, unlike auroras, which typically occur over higher latitudes.

Scientists had thought there was too much light pollution over Europe for the dim, red arcs to be visible. But now, the new All-Sky Imaging Air-Glow Observatory (ASIAGO), located in northern Italy, is using cameras with highly sensitive sensors and a fish-eye lens to observe these red arcs and faint auroral activity over most of the continent.

An international team of scientists watched the sky with the observatory during a geomagnetic storm that struck Earth in 2011. After comparing their observations with satellite- and ground-based observations, the researchers found that red arcs could reach all the way down to Europe, stretching from Ireland in the west to Belarus in the east.

The fact that scientists can now see these arcs over Europe means that, in combination with similar data from the Americas and the Pacific Ocean, researchers can now see how long the arcs stretch across vast distances over the planet "and thus how long it takes the magnetosphere to be drained of its storm-time energy," researcher Michael Mendillo, a space physicist at Boston University, told OurAmazingPlanet. (Red arcs happen when oxygen atoms in the ionosphere emit light, after being excited by electrons heated at greater heights in Earth's magnetosphere.)

Read more at Discovery News

Deep-Sea Vent Life Not Living Fossils

Deep in the ocean, bizarre creatures colonize deep-sea hydrothermal vents, where boiling water laden with minerals builds otherworldly towers.

The animals and bacteria thrive on chemicals and live without sunlight, an ecosystem separate from life on land. When they were first discovered in the 1970s, scientists suggested the hydrothermal vent systems might be living fossils, untouched by surface events for hundreds of millions of years.

But genetic evidence suggests the modern versions of these strange life forms arose only after the last mass extinction on Earth, when a giant meteor impact killed the dinosaurs 65 million years ago. The first vent animals appeared 500 million years ago.

"We can't assume that these things are protected from what's happening at the surface of the planet," Bob Vrijenhoek, a biologist at the Monterey Bay Aquarium Research Institute, said in a statement. "They are every bit as susceptible as the surface organisms."

Vrijenhoek suggests that extreme global events could have shifted deep ocean chemistry enough to disrupt the chemical reactions bacteria rely on to convert vent chemicals into food.

Read more at Discovery News

Organic Labels Bias Consumers Perceptions Through the 'Health Halo Effect'

The word "organic" can mean many things to consumers. Even so, the power of an organic label can be very strong: studies have shown that this simple label can lead us to think that a food is healthier, through what is known as the 'health halo effect'. But can this bias go further?

A study by Cornell University's Food and Brand Lab researchers Wan-chen Jenny Lee, Mitsuru Shimizu, Kevin M. Kniffin and Brian Wansink set out to answer this question. Their study shows that an organic label can influence much more than health views: perceptions of taste, calories and value can be significantly altered when a food is labeled "organic." Certain people also appear to be more susceptible to this 'health halo' effect than others…are you?

115 people were recruited from a local shopping mall in Ithaca, New York to participate in this study. Participants were asked to evaluate 3 pairs of products -- 2 yogurts, 2 cookies and 2 potato chip portions. One item from each food pair was labeled "organic," while the other was labeled "regular." The trick to this study was: all of the product pairs were organic and identical! Participants were asked to rate the taste and caloric content of each item, and how much they would be willing to pay for the items. A questionnaire also inquired about their environmental and shopping habits.

Even though these foods were all the same, the "organic" label greatly influenced people's perceptions. The cookies and yogurt were estimated to have significantly fewer calories when labeled "organic" and people were willing to pay up to 23.4% more for them. The nutritional aspects of these foods were also greatly biased by the health halo effect. The "organic" cookies and yogurt were said to taste 'lower in fat' than the "regular" variety, and the "organic" cookies and chips were thought to be more nutritious! The label even tricked people's taste buds: when perceived as "organic," chips seemed more appetizing and yogurt was judged to be more flavorful. "Regular" cookies were reported to taste better--possibly because people often believe healthy foods are not tasty. All of these foods were exactly the same, but a simple organic label made all the difference!

Read more at Science Daily

Crucial Step in Human DNA Replication Observed for the First Time

For the first time, an elusive step in the process of human DNA replication has been demystified by scientists at Penn State University. According to senior author Stephen J. Benkovic, an Evan Pugh Professor of Chemistry and Holder of the Eberly Family Chair in Chemistry at Penn State, the scientists "discovered how a key step in human DNA replication is performed."

The results of the research will be published in the journal eLife on 2 April 2013.

Part of the DNA replication process -- in humans and in other life forms -- involves loading of molecular structures called sliding clamps onto DNA. This crucial step in DNA replication had remained somewhat mysterious and had not been well studied in human DNA replication. Mark Hedglin, a post-doctoral researcher in Penn State's Department of Chemistry and a member of Benkovic's team, explained that the sliding clamp is a ring-shaped protein that acts to encircle the DNA strand, latching around it like a watch band. The sliding clamp then serves to anchor special enzymes called polymerases to the DNA, ensuring efficient copying of the genetic material. "Without a sliding clamp, polymerases can copy very few bases -- the molecular 'letters' that make up the code of DNA -- at a time. But the clamp helps the polymerase to stay in place, allowing it to copy thousands of bases before being removed from the strand of DNA," Hedglin said.

Hedglin explained that, due to the closed circular structure of sliding clamps, another necessary step in DNA replication is the presence of a "clamp loader," which acts to latch and unlatch the sliding clamps at key stages during the process. "The big unknown has always been how the sliding clamp and the clamp loader interact and the timing of latching and unlatching of the clamp from the DNA," said Hedglin. "We know that polymerases and clamp loaders can't bind the sliding clamp at the same time, so the hypothesis was that clamp loaders latched sliding clamps onto DNA, then left for some time during DNA replication, returning only to unlatch the clamps after the polymerase left so they could be recycled for further use."

To test this hypothesis, the team of researchers used a method called Förster resonance energy transfer (FRET), a technique of attaching fluorescent "tags" to human proteins and sections of DNA in order to monitor the interactions between them. "With these tags in place, we then observed the formation of holoenzymes -- the active form of the polymerase involved in DNA replication, which consists of the polymerase itself along with any accessory factors that optimize its activity," Hedglin said. "We found that whenever a sliding clamp is loaded onto a DNA template in the absence of polymerase, the clamp loader quickly removed the clamp so that free clamps did not build up on the DNA. However, whenever a polymerase was present, it captured the sliding clamp and the clamp loader then dissociated from the DNA strand."

The team members also found that, during the moments when both the clamp loader and the clamp were bound to the DNA, they were not intimately engaged with each other. Rather, the clamp loader released the closed clamp onto the DNA, allowing an opportunity for the polymerase to capture the clamp, completing the assembly of the holoenzyme. Subsequently, the clamp loader dissociated from DNA. "Our research demonstrates that the DNA polymerase holoenzyme in humans consists of only a clamp and a DNA polymerase. The clamp loader is not part of it. It disengages from the DNA after the polymerase binds the clamp," Hedglin added.

Read more at Science Daily

Where Does April Fools' Day Originate?

Despite having no official recognition, April 1 has long been celebrated as a day to celebrate, well, foolishness to be exact. More specifically, April Fools’ Day is about making other people look stupid with practical jokes.

As dearly as we hold the tradition of making fools of the people we care about, there’s little more than theories about where April Fools’ Day came from. Figuring out the origins of the holiday can be as tricky as getting to the source of a joke.

The most common theory about the earliest April Fools’ celebrations goes like this: In 1582, Pope Gregory XIII issued a papal bull decreeing a new standard calendar for Christian Europe that would take his name and centuries later become the standard internationally in the 21st century.

Prior to the 15th century, Europe’s nations and city states operated using the Julian calendar. The Gregorian calendar moved the date of the new year from April 1 to January 1, among other changes. Catholic monarchies were naturally its earliest adopters, though Protestant nations later followed suit.

Given the nature of the reform, both in terms of communicating such a fundamental change to a large population and dealing with critics of the new calendar, some Europeans continued to celebrate the new year between March 25 and April 1. April fools were those who still celebrated the holiday in the spring, and were the subject of pranks and ridicule by those who observed the new year months ago.

That’s just one theory for the origin of the holiday, however. As HowStuffWorks.com notes on a piece about the holiday’s traditions, other occasions resembling April Fools’ Day preceded the more contemporary incarnation by centuries.

Ancient Romans held a festival known as Hilaria. The occasion was used to celebrate the resurrection of the god Attis. Hilaria, of course, resembles the word hilarity in English. The modern equivalent of Hilaria is called Roman Laughing Day.

Other non-Western cultures have their own traditions similar to April Fools’ Day as well. In India, Holi, a colorful Hindi festival that frequently entices non-Hindi participants to join in, often is celebrated by people playing jokes and throwing colorful dyes on each other.

Read more at Discovery News

How Ancient Life May Have Come About

A family tree unites a diverse group of individuals that all carry genetic vestiges from a single common ancestor at the base of the tree. But this organizational structure falls apart if genetic information is a communal resource as opposed to a family possession.

Some evidence suggests that early evolution may have been based on a collective sharing of genes. A group of researchers are now searching for clear genetic vestiges from this communal ancestry.

But it's hard to shake our fascination with family trees.

My father used to travel for work, and when he arrived in a new city, he'd open up the phone book and check for anyone listed with our uncommon last name. Occasionally he'd get a hit and brazenly call them up to ask: "Are we related?"

The answer was always yes, with the common link often being my great grandfather.

Like my father, biologists are curious about family ties, but they go about it in a more systematic way. Rather than phone books, they sift through genetic codes from humans to bacteria and a lot in between. The main question is: Are the commonly held genes similar enough to point to a common origin?

The answer has always been yes. The implication is that we all belong to some universal tree of life. And at the base of this tree — some have imagined — there sits a mild-mannered microbe that lived more than 3 billion years ago, unaware that its genes would be the starting point of an entire planet's worth of highly differentiated life.

However, this organism, the so-called last universal common ancestor (or LUCA), may be just a fantasy.

"Our perspective is that life emerged from a collective state, and so it is not at all obvious that there is one single organism which was ancestral," said Nigel Goldenfeld from the University of Illinois at Urbana-Champaign.

The organisms belonging to this collective state would have shared genetic information from neighbor to neighbor, rather than solely from parent to offspring. Goldenfeld is leading a new NASA Astrobiology Institute (NAI) team that aims to provide a clearer understanding of this early stage of evolution.

"We are hoping to find fossils of the collective state in the genomes of organisms," Goldenfeld said.

Goldenfeld's team will be performing genetic studies that will try to tease out signatures of community-based evolution. They will complement this field and laboratory work with theoretical modeling and computer simulations.

"The ultimate goal is to understand how our planet's biochemistry is an instantiation of the universal laws of life, thus addressing the question of whether life is an inevitable and thus widespread outcome of the laws of physics," Goldenfeld said.

A time before Darwinism

It might sound strange that an organism's genetic code could be the result of "crowdsourcing." We are more familiar with traditional reproduction, as practiced by the birds and the bees.

In so-called "vertical gene transfer," an organism inherits its genome from its parents, but it does not receive an exact copy. Small changes enter the code through reproductive mixing and mutations. This "descent with modification," as Darwin put it, eventually allows a population of interbreeding organisms (or species) to evolve.

If every snippet of DNA was solely the product of descent with modification, then every organism could be placed on a tree of life stemming from a single ancestor. But as it turns out, "different genes go back to different ancestors," said Peter Gogarten of the University of Connecticut, who has done extensive work on comparative genetics.

How is that possible? It can happen if organisms share genes. Imagine a gene belonging to members of a specific family tree. One day, this gene becomes isolated and gets picked up by another organism with a different family tree. No reproduction between partners takes place — only an "adoption" of a specific gene.

This so-called "horizontal gene transfer" is quite common among bacteria and archaea, as exemplified by antibiotic resistance. When a specific bacterium develops a defense against some drug, the corresponding gene can pass horizontally to others in the same colony.

A 2008 study in the journal Proceedings of the National Academy of Sciences (PNAS) found that 80 percent of the genes in bacteria were horizontally transferred at some point in the past.

Complex organisms also exhibit evidence of horizontal (or lateral) gene transfer, albeit to a lesser extent. Researchers have shown that ancient ancestors of plants and animals "swallowed up" other bacteria to form symbiotic relationships, which eventually resulted in specialized cellular components, such as mitochondria and chloroplasts.

In his work, Gogarten has shown that horizontal gene transfer turns the tree of life into a thick bush of branches that interweave with each other. Many of these branches terminated long ago due to extinction, but some of their genes live on in us, thanks to horizontal gene transfer.

Several studies suggest that horizontal gene transfer was more prevalent in the past when nothing but single-celled organisms inhabited the Earth.

"I like to think of early life as being more like an undifferentiated slime mold," Goldenfeld said. "Such a communal form of life would have no meaningful family tree, because it is the community that varies in descent, not individual organismal lineages."

Evolving evolution

The late Carl Woese, a colleague of Goldenfeld, was one of the first scientists to propose that early life leaned heavily on horizontal gene transfer. Woese passed away in December of last year. He is perhaps best-remembered for classifying life into the now-well-accepted domains of bacteria, eukaryotes (plants, animals, fungi and protists) and archaea.

In 1987, Woese wrote about the consequences of rampant horizontal gene transfer. In such a scenario, "a bacterium would not actually have a history in its own right: It would be an evolutionary chimera."

A "chimera" is the name of a creature from Greek mythology that mixed together features of a lion, a goat and a snake. This hybridization presumably gave the chimera an advantage over its "competitors."

In a 2006 PNAS paper, Kalin Vetsigian, Woese and Goldenfeld showed that microbial chimeras may also have an advantage over their biological counterparts. The researchers used computer models to demonstrate that the genetic code could evolve more efficiently if organisms shared their genes collectively. Horizontal gene transfer turned out to be a better "innovation-sharing protocol" than vertical (Darwinian) transfer.

Now, with his NAI team, Goldenfeld wants to confirm these simulations with genetic studies. Specifically, they will target archaea, whose genes have yet to be scrutinized as closely as those from the other domains, Goldenfeld said.

The group is particularly interested in the question of how the ability to evolve originally developed. The "evolution of evolution" sounds like a chicken-and-egg problem — especially if you think, as Goldenfeld does, that life is by definition something capable of evolving.

However, evolution can utilize different mechanisms to achieve the same goal. Goldenfeld's team will try to recover some of life's former evolutionary phases by stressing cells and then seeing how their genomes rearrange in response.

Read more at Discovery News