Flower forms in the primrose: Biologists unlock 51.7-million-year-old genetic secret to landmark Darwin theory

Primrose

Scientists have identified the cluster of genes responsible for reproductive traits in the common primrose flower (Primula vulgaris), first noted as important by Charles Darwin more than 150 years ago.

Darwin hypothesised that some plant species with two distinct forms of flower, where male and female reproductive organs were of differing lengths, had evolved that way to promote out-crossing by insect pollinators.

His ground-breaking insight into the significance of the two forms of flower known as 'pins' and 'thrums' coined the term 'heterostyly', and subsequent studies contributed to the foundation of modern genetic theory.

And now scientists at the University of East Anglia, working at the John Innes Centre, have identified exactly which part of these species' genetic code made them that way, through an event that occurred more than 51 million years ago.

Prof Philip Gilmartin from UEA's School of Biological Sciences said: "To identify the genes which control the biology noted by Darwin is an exciting moment. Many studies have been done over the past decades to explore the genetic basis of this phenomenon but now we have pinpointed the supergene directly responsible, the S locus."

Supergenes are clusters of closely-associated genes which are always inherited together as a unit and allow complex biology to be controlled. Researchers worked with the Earlham Institute to map the plant's genes and sequence the Primula genome to find the specific gene cluster responsible for creating the differing flower morphs.

Prof Gilmartin said: "Not only did we identify the supergene but we found it is specific to just one of the flower forms, the thrum. This insight has profound implications for our understanding of a key evolutionary innovation of flowering plants.

"Understanding of the genetics which underpin flower development and reproduction of a species broadens our knowledge about the entire system of pollination, which underpins biodiversity and food security.

"With challenges such as climate change and its effects on plants, crops and their insect pollinators, it's even more important to understand pollination mechanisms and how species can and will react.

In their hunt for the genes controlling heterostyly, researchers also managed to date the original mutation, to 51.7 million years ago.

Having found the S locus, they realised the gene was a close relative to another, identified six years ago as responsible for controlling the identity of petals on a Primula flower.

At some point this gene duplicated, inserted itself in the S locus, and mutated to control the position of the anther in the flower. Finding this duplicated gene allowed the team to date how long ago the mutation occurred for the first time.

Read more at Science Daily

New evidence on the formation of the solar system

Supercomputer model of a low-mass supernova.

International research involving a Monash University scientist is using new computer models and evidence from meteorites to show that a low-mass supernova triggered the formation of our solar system.

The research is published in the most recent issue of leading scientific journal Nature Communications.

About 4.6 billion years ago, a cloud of gas and dust that eventually formed our solar system was disturbed.

The ensuing gravitational collapse formed the proto-Sun with a surrounding disc where the planets were born. A supernova -- a star exploding at the end of its life-cycle -- would have enough energy to induce the collapse of such a gas cloud.

"Before this model there was only inconclusive evidence to support this theory," said Professor Alexander Heger from the Monash School of Physics and Astronomy.

The research team, led by University of Minnesota School of Physics and Astronomy Professor Yong-Zhong Qian, decided to focus on short-lived radioactive nuclei only present in the early solar system.

Due to their short lifetimes, these nuclei could only have come from the triggering supernova. Their abundances in the early solar system have been inferred from their decay products in meteorites. As the debris from the formation of the solar system, meteorites are comparable to the leftover bricks and mortar in a construction site. They tell us what the solar system is made of and in particular, what short-lived nuclei the triggering supernova provided.

"Identifying these 'fingerprints' of the final supernova is what we needed to help us understand how the formation of the solar system was initiated," Professor Heger said.

"The fingerprints uniquely point to a low-mass supernova as the trigger.

"The findings in this paper have opened up a whole new direction of research focusing on low-mass supernovae," he said.

In addition to explaining the abundance of Beryllium-10, this low-mass supernova model would also explain the short-lived nuclei Calcium-41, Palladium-107, and a few others found in meteorites.

Professor Qian said the group would like to examine the remaining mysteries surrounding short-lived nuclei found in meteorites. The research is funded by the US Department of Energy Office of Nuclear Physics.

Professor Heger and a new Monash Future Fellow, Dr Bernhard Mueller, also study such supernovae using computational facilities at the Minnesota Supercomputing Institute.

From Science Daily

Learning makes animals intelligent

An orangutan builds an umbrella against the rain. Efficient and intelligent behaviour that can be explained by new research from Stockholm University and Brooklyn College.

The fact that animals can use tools, have self-control and certain expectations of life can be explained with the help of a new learning model for animal behaviour. Researchers at Stockholm University and Brooklyn College have combined knowledge from the fields of artificial intelligence, ethology and the psychology of learning to solve several problems concerning the behaviour and intelligence of animals.

Animals are often very effective; an oystercatcher opens mussels quickly, a baboon takes every opportunity to steal food from tourists or a rat navigates with ease between the bins in a park. Previously these behaviours have been considered to be inherited instincts, even though it is well known that animals have great learning abilities. Researchers from Stockholm University and Brooklyn College have now created an associative learning model that explains how effective behaviours can arise. This means that an animal does not only learn that the last step of a behaviour chain, the one that is rewarding, is valuable. An animal can learn that all steps towards the reward are valuable.

"Our learning model may also explain how advanced behaviours are created at an individual level. Behaviours like self-control, chimpanzee tool use as well as other phenomena like animals having certain expectations of live," says Magnus Enquist, professor of ethology at Stockholm University. "Similar models are used in the field of artificial intelligence, but they have been ignored in animal studies."

Since the 1970s it has been known that animals weigh the cost of a certain behaviour against the profit and that they, to a high degree, make optimal decisions, which is assumed to be genetically determined. The research group's new model deals not only with learning, it also takes into account the idea that what animals are able to learn can be genetically regulated.

"Young animals are often a bit clumsy, while adult animals are extremely skilled. A small cub does not even consider a vole as food, while an adult fox is an expert vole catcher," says Johan Lind associate professor of ethology at Stockholm University. "Our model shows how genetic regulation of learning can influence the development of species-specific behaviour and intelligence since evolution can affect curiosity and the speed of learning among other things."

The researchers' new model could also explain counterproductive behaviour in artificial environments.

"Many learning models can explain optimal behaviour, but to explain counterproductive behaviour an understanding of the mechanisms of the behaviour is needed. Using our model, we manage to explain why animals get stuck in suboptimal behaviour. Like a hamster running in its hamster wheel despite having food next to it. Our model has captured fundamental aspects of learning," says Stefano Ghirlanda, professor of psychology at Brooklyn College in New York.

Read more at Science Daily

Some Viking Left His Toolbox at a Danish Fortress 1,000 Years Ago

A Viking toolbox found in Denmark has been opened for the first time in 1,000 years, revealing an extraordinary set of iron hand tools that may have been used to make Viking ships and houses, according to archaeologists.

The tools were found this summer at a mysterious, ring-shaped fortress at Borgring, on the island of Zealand. The famed 10th-century Danish king Harald Bluetooth is thought to have ordered the construction of the fortress.

So far, archaeologists have found at least 14 iron tools inside a single deposit of earth excavated from a gatehouse building of the fortress. The researchers said only traces remain of the wooden chest that once held the tools.

Iron was valuable in Viking-age Denmark, and the researchers think the tools once belonged to a craftsman who occupied a workroom in the gatehouse until it collapsed in the late 10th century.

The archaeologists are still studying the heavily rusted objects, but they've already identified several sophisticated hand tools and other metal items, including a set of "spoon drills" that were used to make holes in timber; what looks like a pair of tweezers or small pliers; a "clink nail" used to fasten wooden planks together; four carefully crafted chain links attached to an iron ring; and a drawplate to make metal wires that may have been used in jewelry.

Archaeologist Nanna Holm, a curator at the Danish Castle Center in Vordingborg who is leading the excavations of the ringed-shaped fort at Borgring, said this is the first time an entire set of tools has been discovered in a Viking workplace.

"This is not an ordinary find," Holm told Live Science. "Not many tools are found in Scandinavia, but the others found before this have all been left for the gods, by being put down in a swamp."

The newfound tools are special because they were found where the craftsman would have been working, she said. "That's why it's so exciting for us to see what's inside, because we can see what one man has used at this specific site," Holm added.

Viking iron

The cache of iron tools was first located by amateur archaeologists using a metal detector near the eastern gate of the buried fortress at Borgring.

That discovery inspired Holm's archaeological team in August to excavate the eastern gatehouse, where they removed the deposit of earth containing all the tools in one piece — a delicate process that took two days.

The next step was to transport the lump of earth, rust and iron to a local hospital, where it was scanned with computed tomography (CT) equipment usually used by doctors to examine the internal organs of their patients.

The CT scans revealed the precise arrangement of at least 14 iron tools, which have since been excavated from the toolbox deposit for individual X-ray studies and preservation before they are put on display in an exhibition next year, Holm said.

All of the tools are heavily corroded, but much of the original iron remains, and even more tools may be hidden in the rust, according to the researchers. "There are a minimum of 14 tools, but I think there are 16 now, from the new X-rays that we've already done," Holm said.

The contents of the toolbox provide a rare glimpse of working life in the late Viking age, she said.

"They can be used for different crafts," Holm said. "We have some spoon drills for making holes in wood, which could be used for building ships or for building houses."

The iron drawplate has a series of small holes of different sizes that were used to make wires from softer metals, the researchers said. "You pulled the metal through each of the holes to make it smaller and smaller, and thinner and thinner," she explained.

The toolbox is an important early find for the archaeologists, who will conduct further excavations at Borgring each summer for the next three years, Holm said. [Fierce Fighters: 7 Secrets of Viking Culture]

The remains of houses and human graves have been found at other Viking ring forts, but the toolbox is the first direct evidence of human habitation at Borgring itself, she added.

"So far, we haven't found any houses, but we now have proof that there were people here — so hopefully, next year, we will find their houses," Holm said.

Read more at Discovery News

Predation on pollinating insects shaped the evolution of the orchid mantis

A typical male orchid mantis, Hymenopus coronatus, from Sarawak, Borneo showing brown and white coloration with transparent wings.

A team of scientists at The Cleveland Museum of Natural History, Australia, and Germany discovered that the orchid mantis looks like a flower due to the exploitation of pollinating insects as prey by its praying mantis ancestors.

By studying the evolutionary relationships of the orchid mantis and its distant relatives, the team discovered that females in the orchid mantis lineage increased in size and changed color over their evolutionary history to gain advantage over large pollinating insects, such as bees, as well as the ability to attract them for predation. However, the morphologically dissimilar males are small and camouflaged, enabling them to live a life of predator avoidance and mate finding. The team found that this difference in males and females, termed sexual dimorphism, was likely the result of female predatory success that favored larger and more conspicuously colored individuals. This result challenges the traditional explanation for sexual dimorphism in arthropods as an increase in female egg production and suggests female predation strategy led to the differing male and female ecologies in the orchid mantises.

The research was published online in the journal Scientific Reports.

Lead author Dr. Gavin Svenson of the Cleveland Museum of Natural History and co-authors used their evolutionary reconstruction of the group to demonstrate that a size increase in floral associated mantises provided access to more prey options, which set the stage for the evolution of floral simulation through size, shape, and color modifications that helped attract insect pollinators as prey. Thanks to a body of ecological research on the orchid mantis previously conducted by co-author Dr. James O'Hanlon of Macquarie University in Australia, it was known that females masquerade as flowers (floral simulation) to attract pollinating insects to eat, but that they do not sit on flowers themselves. This knowledge helped the team decipher the likely evolutionary scenario that gave rise to floral simulation in the orchid mantises and provided the opportunity to correct the long-held misunderstanding that orchid mantises sit on orchids, which their namesake incorrectly suggests.

"This study is a demonstration of how basic systematics research can inform our understanding of evolution by establishing patterns not previously seen," said co-author Henrique Rodrigues.

"Bringing together ecological research with an evolutionary analysis enabled us to explain how such a remarkable, flower masquerading lineage of praying mantis could evolve," said co-author Sydney Brannoch. Co-authors Rodrigues and Brannoch are both Ph.D. candidates at Case Western Reserve University and are based at the Cleveland Museum of Natural History in Svenson's laboratory.

The research project, under the direction of Svenson, was primarily focused on the systematics and taxonomy of a broader lineage of praying mantises, which included the orchid mantises. Acting on a suggestion made by co-author Dr. Frank Wieland of the Palatinate Museum of Natural History in Germany, the team took notice of a small group of extremely large and colorful mantises that grouped together in the evolutionary analysis. Although these relationships were never before outlined, they suggested a clear pattern of extreme sexual dimorphism in the orchid mantis lineage.

Read more at Science Daily

Cassini Probe Begins Tango With Saturn's Rings

In less than 10 months, NASA's Cassini spacecraft will swan dive into Saturn, ending a 20-year trip around the ringed beauty and its entourage of moons. But before it goes, scientists plan some parting gifts.

This week, Cassini made its penultimate swing past Titan, the largest of Saturn's 62 named moons, so it could be gravitationally elbowed into a new orbit that is more perpendicular to Saturn's equator and rings.

The new path shoots Cassini through the edge of the outer ring, giving scientists unprecedented opportunities to sample ring particles, sniff surrounding gases, blast the rings with radio waves and snap some stupendous pictures.

The first pass by the F ring will occur on Sunday, with 19 more ring-grazing orbits to follow at a pace of one a week.

For its closing act, Cassini will make a final swoop by Titan and go nearly polar around the planet so it can swoop between Saturn and the inner ring.

The journey ends on Sept. 15, 2017, when Cassini plunges into Saturn's thick atmosphere to prevent a most unlikely, but not impossible scenario: contaminating any potentially habitable moons with hitchhiking Earth microbes tenacious enough to have survived 20 years in the radioactive environment of space.

NASA plans to end the mission before Cassini runs out of fuel for its steering thrusters. But for the next 9.5 months, that's the furthest thing from scientists' minds.

From Discovery News

Hubble Spies a Strange Old Dusty Galaxy

The Hubble Space Telescope is an expert at imaging distant galaxies, bringing mysterious galactic features into the light. In the case of one particular elliptical galaxy, around 150 million light-years distant, Hubble has revealed a conundrum and a possible mechanism behind why some galaxies look so old.

NGC 4696 possesses huge clouds of dust and gas, spiraling through the galaxy's structure to its core, but this material isn't being used for star formation. In fact, NGC 4696 is populated with ancient stars and researchers hope to use this stunning example to help us understand why there are so many massive galaxies like it.

NGC 4696 occupies the huge Centaurus galaxy cluster which consists of hundreds of galaxies bound together by gravity. Though the cluster is vast, NGC 4696 stands out from the crowd as it is so bright. It's so bright, in fact, that it has the moniker "Brightest Cluster Galaxy." It is known to have an active core occupied by a supermassive black hole that appears to be consuming these beautiful spiraling tendrils.

These dusty structures have a width of around 200 light-years and they all knit together, creating a conveyor belt of material flooding into the black hole. The black hole then heats the material that spirals in, blasting superheated gases away from the core that sculpt the infalling dust into the shape as seen so clearly by Hubble.

It's well known that central supermassive black holes, which are known to live in the cores of the vast majority of galaxies, have a significant role in regulating the amount of star formation.

In the case of NGC 4696, it appears the galaxy's core is physically shaping the structure of these dusty tendrils and an international team of astronomers, headed by researchers at the University of Cambridge, suspect that powerful magnetic fields are threading through the galaxy's structure, corralling the dust in such a way that its funneled into the black hole. But the black hole is the engine behind it all, erupting with hug amounts of energy and actively stifling star formation.

From Discovery News

Ancient Wind God Temple Found Under Mexico City Supermarket

Archaeologists excavating the site of a demolished supermarket in Mexico City have unearthed a circular temple built more than 650 years ago for an Aztec deity.

The platform, about 36 feet in diameter and four feet tall, was part of the sacred area of the city-state Tlatelolco and was likely dedicated to the god of wind Ehecatl-Quetzalcoatl. It now stands just yards away from the site of the Tlatelolco 1968 massacre, where Mexican soldiers killed protesting students.

The 10-foot deep excavation began two years ago when an old supermarket at the site was demolished. The work first revealed the upper part of the structure, along with pottery shards and 20 burials, which included adults, children and animals.

In March of this year, archaeologists led by Edwina Villegas Gómez, director of the archaeological area of Tlatelolco, brought to light the circular platform with its original white stucco still intact.

At the eastern entrance of the temple, they found a small, stone coffin-like box. Offerings inside included the remains of a newborn child with no signs of trauma, cactus thorns, bird bones, incense burners and pieces of obsidian and pottery depicting monkeys and duck bills.

In early October, the skull of an adult male was also found. Next to it, there was a ring which was worn by the individual.

According to INAH, Mexico's National Institute of Anthropology and History, burials around the temple contained eight complete skeletons (six infants, an adult female and an adult male), as well as other incomplete human remains.

The finding offers another example on how the Mexica-Tlatelolca people worshiped their deities, and adds a new piece to the great puzzle of Tlatelolco's ceremonial center, which is now mostly covered by urban developments.

Preservationists plan to build a protective wall around the site, including a large viewing window and ramp to make it visible to the public.

From Discovery News

A Mysterious Snake Disease Is Spreading as the Planet Warms

When Matthew Allender of the University of Illinois at Urbana-Champaign first saw snake fungal disease victims in 2010, he knew that he was witnessing a devastating illness. He told Seeker, "You could hardly even tell that they were snakes, since some were so disfigured."

The disease, caused by a fungus called Ophidiomyces ophiodiicola, can result in thickened skin, ulcers, blisters, emaciation and, in the majority of cases, death. It has infected over 20 species of wild snakes and has spread to snakes in at least 20 U.S. states, parts of Canada, and to captive snakes in many countries. Scientists say the spread of the disease is an ominous symptom of climate change.

There is some good news to report—the very recent discovery of a promising treatment—at least for captive snakes.

The treatment, which was announced at an American Association of Zoo Veterinarians meeting and will be outlined in a future paper, centers on a nebulizer. People with asthma use similar devices, which are readily available at everywhere from discount shops to "big-box" stores.

Here's how it works: A sick snake is placed in a fish tank-resembling chamber before an anti-fungal agent is pumped in via the nebulizer. The medicated "steam falls on the skin and the snake inhales it," Allender said.

While the process seems to clear up visible signs of the disease, treating wild snakes isn't terribly practical. The elusive nature of snakes, not to mention the need to capture and then diagnose wild-living victims of the disease, complicate implementing the cure. It holds promise for treating pet snakes and others in captivity, however, such as snakes at zoos.

Still, it remains unknown if snakes could still internally harbor the fungus and later pass it on to others of their own kind. (There are no known cases of it spreading to humans.)

Ideally the disease could be wiped out in the wild, but many mysteries still surround it, including how it might be connected to other fungal diseases, including those affecting humans.

"Over 80 percent of emerging diseases are fungal infections," Allender said. "A big question now is if they are all somehow linked."

He and his colleagues note that there are parallels between snake fungal disease and white-nose syndrome, an often-deadly infection affecting bats that is caused by the Pseudogymnoascus destructans fungus. Both pathogens seem to have spread quickly in recent years, and both can survive on most carbon and nitrogen sources found in soils, making them prevalent in the environment.

While it's largely believed that the white-nose pathogen was introduced into North America in more recent years, the presence of O. ophiodiicola in America has been known for some time. It was considered to be a relatively benign organism before one or more triggers likely led to it becoming a snake killer.

Northern water snake with fungal infection-caused deformity.

In a study published earlier this year, Allender and his colleagues evaluated how common disinfectants work against the fungus. Alcohol, bleach and certain other over-the-counter cleaners did a good job, but intriguingly, a common agricultural fungicide did not. He said further studies are needed to determine what role, if any, the fungicide's active ingredient—propiconazole—could play in the spread of snake fungal disease.

Jeffrey Lorch, a microbiologist with the U.S. Geological Survey National Wildlife Health Center, told Seeker that he does not believe there is a connection between these particular agricultural fungicides and the emergence of the disease "unless the fungicides are causing the immune system of snakes not to function properly."

Although the jury is still out on this matter, both he and Allender say climate change is contributing to the prevalence and severity of snake fungal disease.

Read more at Discovery News

Astronomers watch star clusters spewing out dust

In the galaxy II Zw 40, dust (shown in yellow) is strongly associated with clusters of stars (shown in orange). UCLA researchers have used new observations of this galaxy to confirm that these stars are creating enormous amounts of dust.

Galaxies are often thought of as sparkling with stars, but they also contain gas and dust. Now, a team led by UCLA astronomers has used new data to show that stars are responsible for producing dust on galactic scales, a finding consistent with long-standing theory. Dust is important because it is a key component of rocky planets such as Earth.

This research is published online today in Astrophysical Journal Letters.

Jean Turner, a UCLA professor in the department of astronomy and physics, her graduate student S. Michelle Consiglio, and two other collaborators observed a galaxy roughly 33 million light-years away. The researchers focused on this galaxy, called "II Zw 40," because it is vigorously forming stars and therefore useful for testing theories of star formation. "This galaxy has one of the largest star-forming regions in the local universe," Turner said.

The researchers, led by Consiglio, obtained images of II Zw 40 using the Atacama Large Millimeter/submillimeter Array telescope. This telescope, located in Chile's Atacama desert, is composed of an array of 66 individual telescopes that function as a single large observatory. In 2011, Turner took a three-month sabbatical from UCLA to help prepare the Atacama Array to be used by the astronomical community. "I helped with reducing data and served as astronomer on duty," she said.

The telescope is sensitive to light in the millimeter and submillimeter part of the electromagnetic spectrum, just slightly shorter than microwaves. Capturing this kind of light requires a telescope at high altitudes -- this one is built on a plateau at 16,400 feet -- because "the Earth's atmosphere is beginning to absorb very strongly at those wavelengths," Turner said. "All ALMA scientists work at a lower elevation because you can't think well at that altitude," she added.

Consiglio and her team observed the central region of II Zw 40, a part of the galaxy with two young clusters of stars, each containing roughly a million stars. By imaging II Zw 40's star clusters at different wavelengths, they constructed a map that traced the dust in the galaxy. Astronomical dust -- made mostly of carbon, silicon and oxygen -- is prevalent in the universe. "If you look at the Milky Way in the sky, it looks kind of patchy and splotchy. That's due to dust blocking the light," Turner said.

The researchers tested whether the location of the galaxy's dust was consistent with the location of the galaxy's star clusters. They found that it was: Consiglio and her team showed that II Zw 40's dust was concentrated within roughly 320 light-years of the star clusters. "The dust is all focused near the double cluster," Turner said. This observation supported their hypothesis that stars are responsible for producing dust. "The double cluster is a 'soot factory' polluting its local environment," Consiglio said.

Scientists have long theorized that stars produce dust by expelling the elements fused deep within their interiors, enriching their host galaxies in elements heavier than hydrogen and helium. However, astronomical data have thus far not backed up that claim. "People have looked for this large-scale enrichment of galaxies, but they haven't seen it before," Turner said. "We're seeing galaxy-scale enrichment and we see clearly where it is coming from."

The researchers propose that the dust enrichment is so obvious in II Zw 40's star clusters because they contain large numbers of very young, massive stars, which are the producers of dust. "The evolutionary time scales of these stars are short enough that you see the dust before it has a chance to get dispersed very far from its source," Turner said. "We're looking at the best place to see dust enrichment, in large star clusters," Consiglio added.

Read more at Science Daily