Helpful Mutations Didn’t Sweep Through Early Humans

Humans probably didn’t get swept up in evolution.

sciencenewsScientists have favored a model of evolution in which beneficial gene mutations quickly and dramatically sweep through a population due to the evolutionary advantages they confer. Such mutations would become nearly universal in a population. But this selective sweep model may not be accurate for humans, a new study indicates. Human evolution likely followed a more subtle and complicated path, say population geneticists Molly Przeworski of the University of Chicago and Guy Sella of Hebrew University of Jerusalem and colleagues.

Computational analysis of 179 genomes belonging to people from Europe, Asia and Africa reveal that selective sweeps have been rare in human evolution, the researchers report in the Feb. 18 Science.

“I’m convinced,” says Andrew Clark, a population geneticist at Cornell University. Clark was among the first to find evidence that selective sweeps can shape evolution. The idea of a favored gene sweeping in to save the evolutionary day is so attractive that other forms of natural selection have been largely ignored, he says. The new study could change that. “I think this will be taken to heart and people will take a step back and start asking what other signatures of selection may be present.”

In the study, the researchers based their analysis on the idea that when a gene containing a beneficial mutation becomes more common over successive generations it drags along big swaths of neighboring DNA. A sweep would happen so quickly that individual changes in the nearby DNA wouldn’t have time to accumulate, so everyone in a population would end up with essentially the same genetic signature in the DNA regions surrounding the beneficial mutation.

The researchers searched for such troughs of genetic diversity around genes carrying mutations that would change an amino acid building block in the protein built from the gene — a sign of functional importance. The team reasoned that if the genetic changes were really beneficial, they ought to have deeper troughs than mutations that don’t alter amino acids.

“But in fact, we found very little difference,” says Sella. That could indicate that “very few of these mutations came into the population in the mode of a selective sweep.” The researchers didn’t find evidence of selective sweeps in regions of the genome that change how genes are turned on and off either.

It may have been difficult for selective sweeps to take hold in humans because of demographics, Clark says. People are scattered throughout the globe, so a beneficial mutation would have a long way to spread. Such a mutation would have to have dramatic effects on evolutionary fitness to go global.

Good evidence does exist for some mutations that did undergo selective sweeps in humans, such as those for skin pigmentation, hair and teeth morphology and the genetic change that allows adults in some populations to digest the milk sugar lactose. But those examples are the exception rather than the rule in human evolution.

Read more at Wired

Priceless Pharaoh Statue Found Near Garbage Can

A limestone statue of the renegade Pharaoh Akhenaten has been recovered beside a garbage bin near the Egyptian National Museum in Cairo from which it had been stolen 20 days ago, Egypt's Ministry of Antiquities said Thursday.

The priceless statue was found by a 16-year-old boy near a trash can in Cairo's Tahrir Square, where the 18-day protest that brought down Hosni Mubarak took place.

"He brought the statue to his home and when his mother saw it she called her brother, Dr. Sabry Abdel Rahman, a professor at the American University in Cairo. Dr. Rahman, in turn, called the Ministry of State for Antiquities Affairs to hand the statue over," said the Ministry of Antiquities Affairs in a statement.

Lying by the garbage, as if it suffered another damnatio memoriae some 3,300 years later, the statue shows Akhenaten wearing a blue crown and holding an offering table in his hands.

"It was returned intact, except for the offering table that was found separately inside the Egyptian museum," the ministry said.

The son of Amenhotep III and most likely the father of Tutankhamun, Akhenaten (1353 B.C. - 1336 B.C.) is known as the "heretic" pharaoh who established the capital of his kingdom in Amarna, introducing a monotheistic religion for the sun god Aten that overthrew the pantheon of the gods.

After his death, when Egypt returned to the traditional religion, Akhenaten's name, images and the traces of his reign were eradicated.

Indeed, the recovered limestone statue is one of the few statues that we have from the Amarna Period.

"The entire reign of Akhenaton was unique. The style of the statues and reliefs produced during a large part of the reign are unique as well," Jacques Kinnaer, a Belgian Egyptologist, creator of The Ancient Egypt Site, told Discovery News.

Akhenaten_Offering"I'm relieved to hear that this priceless statue has been recovered," Kinnaer said.

Described to have suffered "very minor damage" during the break-in at the museum on Jan. 28, 2011, the statue is slated to be the "the first object that will be cleaned and restored."

The limestone carving was declared missing last Saturday along with other 17 artifacts, then daringly recovered near a garbage at a public square. It has become the symbol of the alternating feelings that have struck the Egyptologist's community in the past two and a half weeks.

Read more at Discovery News

Primitive Dinosaur Found in Antarctic Mountains

Paleontologists working high in a remote range of Antarctic mountains have found a new species of primitive dinosaur dating back to nearly 200 million years ago -- a time when one of the coldest parts of the world was a temperate forest.

William Hammer of Augustana College found the new creature -- a four- to five-foot ornithischian or bird-hipped dinosaur that he believes is related to the fabrosaur or heterodontosaur.

These dinosaurs were the forerunners of the bigger and more spectacular ornithischians like stegosaurus,ankylosaurus and the duck-billed dinosaurs.

The fossils came from a site on Mt. Kirkpatrick, in the Central Trans-Antarctic Mountains, which divide east and west Antarctica. It's the same place where Hammer and colleagues found Antarctica's first dinosaur in 1990 -- the 22-foot, meat-eating Cryolophosaurus, or "frozen crested reptile."

Hammer found more parts of that dinosaur as well as a large sauropod, or plant-eater, resembling a diplodocus, and the new, as-yet-undescribed ornithischian.

 "I don't know if we have a head, but we have a leg and a foot," he said. "It will take us a year to get a handle on what we've got."

Hammer and several fellow researchers camped at Beardmore Glacier at 6,600 feet for nearly two months. Each day fossil-hunting crews would be flown up by helicopter to the fossil beds at 12,500 feet elevation.

The new find could fill in gaps in the evolution of dinosaurs as well as the Antarctic environment, according to Thomas Holtz, professor of geology at the University of Maryland.

"This is a time when dinosaurs had just taken over," Holtz said.  "They are the rabbits of the plant-eating dinosaurs: small, common, fairly fast, and they didn't have a lot of armor. They almost never show up in the movies or nobody makes plastic toys of them, but they are the stock from which the greatest plant eating dinosaurs evolved."

Read more at Discovery News

Out-of-body experiences are just the product of a confused mind

Throughout history people have described how they have floated from their bodies and looked back at themselves, often when close to death or on the operating table.

The accounts have been so vivid that they are often cited as proof of the existence of the soul or Heaven.

But scientists now claim they have dispelled this myth by artificially creating an out-of-body experience using computers and cameras.

They believe the feeling of detachment occurs when the brain becomes confused by conflict between the senses - and is not proof of any "spiritual dimension" to existence.

Professor Olaf Blanke and his team at University of Geneva said they had "immersed" volunteers into the body of an avatar - a computer generated version of themselves.

Volunteers were asked to wear virtual reality goggles and then stand in front of a camera.

The subjects saw the cameras view of their back on screens in the goggles, computer enhanced to create a 3D virtual version or avatar.

When their back was stroked with a pen so was the virtual avatar in front of them, making them think that the virtual body was in fact their own.

In this way people became confused about their real and the virtual self - even though they were effectively two metres apart from each other.

Prof Blanke, who presented his findings at the American Association for the Advancement of Science (AAAS) conference in Washington, said: "Through vision and touch they lost themselves.

"They start thinking that the avatar is their own body. We created a partial out-of-body experience.
"We were able to dissociate touch and vision and make people think that their body was two metres in front of them."

He said by inducing the out-of-body experience it proved it was more like a brain malfunction when sight, touch and balance become confused.

Dr Blanke said: "Instead of it being a spiritual thing, it is the brain being confused. Why do we think that it is spiritual when we don't think a phantom limb when one is lost is an example of the paranormal."

To take the research further they used sensors connected to the skull to find the areas of the brain most involved in deciding where it belongs.

These were found to be temporo-parietal and frontal regions - parts at the front and right side of the brain responsible for integrating touch and vision.

If these were damaged or somehow short-circuited it could account for the feeling of floating above your body often associated with an out-of-body experiences.

Aside from explaining out-of-body experiences, the work could have more commercial applications, said the researcher.

Read more at The Telegraph

Storm to bring Northern Lights to Britain

“Britain should experience spectacular Northern Lights displays from Thursday due to a large solar storm which could disrupt communication networks, the British Geological Survey (BGS) said.

“Since February 13 three energetic solar flares have erupted on the sun and spewed clouds of charged plasma called coronal mass ejections (CMEs) out towards the earth,” a BGS geomagnetic storm warning said.

“Already one CME arrived on the 14th sparking Valentine’s Day displays of the Northern Lights (aurora borealis) further south than usual.

“Two CMEs are expected to arrive in the next 24-48 hours and further…displays are possible some time over the next two nights if skies are clear.”

The strongest storm in four years is expected to interfere with satellites and electrical networks, with astronomers in southern China already reporting disturbances to radio communications.

The BGS Wednesday published geomagnetic records dating back to the Victorian era which it hopes will help in planning for future storms.

“Life increasingly depends on technologies that didn’t exist when the magnetic recordings began,” Alan Thomson, BGS head of geomagnetism said.

“Studying the records will tell us what we have to plan and prepare for to make sure systems can resist solar storms,” he added.”

Read more at Yahoo News

A history of cannibalism

The earliest evidence of cannibalism was discovered in Gran Dolina, Spain, where about 780,000 years ago, six individuals were butchered.

Another important site is in Moula-Guercy, France, where evidence of cannibalism taking place 100,000 years ago was found.

Cannibalism stretched far and wide and evidence of its practice was also found in South Africa, 80,000 years ago, and in America circa 1100AD.

In more recent times the Aztecs of the 15th century in Mexico engaged in cannibalism.

Cannibalism, in the form of human sacrifice, was a major aspect of Aztec culture. Some archaeologists claim it was because of psychological and sociological factors while others claim they saw it as a necessary part of their diet.

There have been a number of reports of cannibalism as recently as the 20th century, notably in wars in Congo and Liberia.

Cannibalism has also featured in books and films, and has been associated with some serial killers.

The book 'Alive: The Story of the Andes Survivors', and a film of the same name, told the story of the Uruguayan Rugby team, their friends and family, who were involved in an aeroplane crashed in the Andes mountains on October 12, 1972.

Of the 45 people on the flight only 16 survived, and over a number of weeks they had to resort to cannibalism to do so.

Jeffrey Dahmer, also known as The Milwaukee Monster and Cannibal, murdered 17 men and boys, many of whom were of African or Asian descent, between 1978 and 1991. He tortured, dismembered, and then ate parts of his victims.

Read more at The Telegraph

Ice age Britons ate each other and made cups from skulls

Scientists have discovered the remains of three humans – including a child-of-three – that appear to have been killed for food, their bodies butchered and then eaten.

The bones showed precision cuts to extract the maximum amount of meat and the skulls had been carved into cups and bowls for drinking and eating.

The fragments – which are 14,700 years old- are thought to be the oldest examples in the world of skull cups and the first evidence of ritual killing in Britain.

What is particularly horrific is that at the time, humans knew how to bury their dead and so were not savages meaning the remains are most likely the result of premeditated cannibalism.

"At the time life was very tough," said Professor Chris Stringer, a palaeontologist at the Natural History Museum, who helped excavate the skull cups.

"Cannibalism would have been a good way of removing groups competing with you and getting food for yourself.

"There was also a feeling that if you ate your enemy you gained some of his power."

At the time Britain was just emerging from the Ice Age and the cavemen – believed to be Cro Magnons originally from France – would have come to Britain from the Netherlands in summer, probably following animal herds migrating across land that is now the North Sea.

Just a few hundred strong, the hunter gatherers would have mainly lived off reindeer and horses but when times got tough it is believed they would have fought and eaten competing groups.

Prof Stringer said they were not savages and knew exactly what they were doing.

"What is more sinister is that these were quite sophisticated hunter gatherers – very like us," said Prof Stringer.

"They could make tools and painted cave art. They also had quite complex burials for the people they were not eating, treating the dead with reverence.

No one can be sure, exactly what happened but the three cadavers, found in Gough's Cave, Somerset, show signs of being chopped up for food.

The 41 pieces of bone, found in 1987 but only just fully analysed, were broken up to remove the marrow and cut marks shows that they were meticulously cleaned to remove all the soft tissues.

Most gruesomely the skulls were shown to have been smashed into cups, the hair scalped from the head, and the tongues and eyes gouged out.

The sharp edges were also cleaned up so that they could be used a drinking cup perhaps to consume "blood, wine or food" during the meal.

But once the feast had been finished the scientists believe that the cannibals discarded the bones and the skull cups and moved on.

Read more at The Telegraph

The Church Of Scientology, Fact-Checked

“Lawrence Wright’s cover story in the current edition of The New Yorker reports on the Church of Scientology and focuses on why screenwriter and director Paul Haggis resigned from the organization in 2009 after spending nearly 35 years with it.

Haggis, who directed Crash and wrote the screenplay for Million Dollar Baby, spoke with Wright about his reasons for leaving the church and the response from his fellow Scientologists.

Wright tells Fresh Air’s Terry Gross about the detailed fact-checking process his article went through — The New Yorker assigned five fact checkers to the story and sent the Church of Scientology 971 fact-checking queries before publication.

In September 2010, Wright, his editor, the New Yorker fact-checking team and the magazine’s editor-in-chief, David Remnick, met for eight hours with the spokesman for the Church of Scientology, Tommy Davis, along with Davis’ wife and four lawyers representing the church, to discuss the facts in the piece.

Wright says that one of the most interesting parts of the meeting came when he asked Davis about L. Ron Hubbard’s medical records. Hubbard, the founder of Scientology, had maintained that he was blind and a ‘hopeless cripple’ at the end of World War II — and that he had healed himself through measures that later became the basis of Dianetics, the 1950 book that became the basis for Scientology.

“I had found evidence that Hubbard was never actually injured during the war. … And so we pressed [Tommy Davis] for evidence that there had been such injuries and [Hubbard] had been the war hero that he described,” says Wright. “Eventually, Davis sent us what is called a notice of separation — essentially discharge papers from World War II — along with some photographs of all of these medals that [Hubbard] had won. … At the same time, we finally gained access to Hubbard’s entire World War II records [through a request to the military archives] and there was no evidence that he had ever been wounded in battle or distinguished himself in any way during the war. We also found another notice of separation which was strikingly different than the one that the church had provided.”"

Read more at NPR

The more you lie, the easier it gets

“Our brains are naturally better at telling the truth than lying, but repeated lying can overcome our tendency for veracity, making subsequent lying easier – and possibly undetectable.

Neuroimaging studies have shown that people’s brains show considerably more activity when they are lying than when they are not, particularly in the prefrontal cortex, suggesting that lying requires extra cognitive control and inhibition of truth-telling. Lying also takes measurably longer than telling the truth.

To test whether the brain’s so-called “dominant truth response” can be changed, Bruno Verschuere of Ghent University in Ghent, Belgium, and colleagues studied three groups of students.

True or false?

The students were first asked to provide a written report about their daily activities. Each student was then questioned about these activities, and asked to either lie or tell the truth in their answers.

Interspersed with these questions were “filler” questions on a new topic. One group was always asked to tell the truth to the filler questions, a second group had to lie, and a third group was asked to lie or tell the truth in equal measure.

The researchers found that the frequent liars became more adept at lying. The normal difference in reaction times between telling the truth and lying disappeared.”

Read more at New Scientist

Are Shrinking Brains Making Us Smarter?

“Human brains have shrunk over the past 30,000 years, puzzling scientists who argue it is not a sign we are growing dumber but that evolution is making the key motor leaner and more efficient.

The average size of modern humans — Homo sapiens — has decreased about 10 percent during that period — from 1,500 to 1,359 cubic centimeters (91 to 83 cubic inches), the size of a tennis ball.

Women’s brains, which are smaller on average than those of men, have experienced an equivalent drop in size.
These measurements were taken using skulls found in Europe, the Middle East and Asia.

“I’d called that a major downsizing in an evolutionary eye blink,” John Hawks of the University of Michigan told Discover magazine.

But other anthropologists note that brain shrinkage is not very surprising since the stronger and larger we are, the more gray matter we need to control this larger mass.

The Neanderthal, a cousin of the modern human who disappeared about 30 millennia ago for still unknown reasons, was far more massive and had a larger brain.

The Cro-Magnons who left cave paintings of large animals in the monumental Lascaux cave over 17,000 years ago were the Homo sapiens with the biggest brain. They were also stronger than their modern descendants.

Psychology professor David Geary of the University of Missouri said these traits were necessary to survive in a hostile environment.

He has studied the evolution of skull sizes 1.9 million to 10,000 years old as our ancestors and cousins lived in an increasingly complex social environment.”

Read more at Discovery News

50 Things That Look Like Faces – Pareidolia

As most of you SHOULD know – Pareidolia “is a psychological phenomenon involving a vague and random stimulus (often an image or sound) being perceived as significant.” It commonly occurs as face-like patterns in inanimate objects, fifty instances of which can be seen after the break, so you can start developing empathy for cheese graters and alarm clocks and houses and things.

Here’s our favorite few we haven’t seen before:

See all 50 over at Geekosystem

Mummies' false toes put a spring in amputees' step

Egyptologist Jacky Finch has a thing for toes – specifically, ancient artificial toes that she believes are the earliest known prostheses. Finch's fetish motivated her to try something no one has ever done before: she recreated these unusual artifacts, strapped them to living volunteers and demonstrated that they could indeed have functioned as surrogate digits.

Her work suggests that prosthetic medicine took its first steps a few hundred years earlier than previously thought.

While studying man-made body parts found on Egyptian mummies, Finch, a researcher at the University of Manchester in the UK, stumbled on the two false big toes on which her latest research rests.

One, called the Greville Chester toe, was found near Luxor, Egypt. It was crafted some time before 600 BC from cartonnage – a kind of papier mâché made of linen and animal glue and covered in tinted plaster. The toe even includes an indentation that likely held an ornamental toenail.

The other belonged to a priest's daughter named Tabaketenmut, who lived sometime between 950 and 710 BC. If Tabaketenmut had diabetes, as some researchers have suggested, she may have lost her toe to ischaemic gangrene. Her prosthesis (shown above) is an elaborate three-piece construction of wood and what Finch thinks is leather, complete with a hinge that might mimic the flexibility of the joints.

Both artificial toes had holes for lacings that likely secured them to the feet.

Read more at New Scientist

Pasta-Shaped Light from Spinning Black Holes Could Challenge Einstein

Rotating black holes could leave a twisty signature on light escaping their gravitational maws. If this screwy light can be detected from Earth, it would give astronomers a new way to detect exotic black holes and a new test of Einstein’s theory of general relativity, says a team of physicists.

“For relativity, it’s very important,” said physicist Martin Bojowald at Penn State University, who was not involved in the new work. “There are very few classic tests of relativity. It now seems that we are pretty close to actually using this.”

Black holes are greedy beasts. Not only do they attract matter so strongly that even light can get trapped in their great gravitational bellies, they also grab hold of the fabric of space-time in their vicinity. When a black hole spins — and astronomers expect that most do, although none have been definitively observed — it swirls its surrounding space-time around with it like water spiraling around a drain.

This phenomenon, called frame-dragging, has been proven to work even around bodies as small as Earth. Observations of two Earth-orbiting satellites over the last few decades show that the satellites drag by several feet per year as Earth’s spin tows the fabric of space and time in circles.

“If you can see it, such a tiny little effect from this minute mass that the Earth has compared to a black hole, how much easier would it be to see it around a black hole?” said space physicist Bo Thidé of the Swedish Institute of Space Physics, coauthor of a paper published online February 13 in Nature Physics. “That’s how we started.”


From other researchers’ experiments using lasers and lenses, Thidé and colleagues knew that light traveling in a straight line can be forced into a spiral if sent through the right kind of lens. The twisted beams come out looking like corkscrew-shaped fusilli pasta, Thidé says.

Read more at Wired

King Tut Statues Stolen From Egypt Museum

Sad news was announced about some of the treasures kept at the Egyptian National Museum just after Hosni Mubarak stepped down as Egypt's president.

According to Zahi Hawass, who under Mubarak was recently named minister of antiquities, some 18 objects went missing following a break-in at the museum on Jan. 28, 2011.

"The staff of the database department at the Egyptian Museum, Cairo, have given me their report on the inventory of objects at the museum following the break in. Sadly, they have discovered objects are missing from the museum," Hawass wrote in his blog.

The artifacts include a limestone statue of Akhenaten holding an offering table (previously announced to have been under restoration), and two gilded wood statues of King Tutankhamun, one of the boy king being carried by a goddess, the other of the pharaoh harpooning.

"Only the torso and upper limbs of the king are missing from this object," Hawass said, referring to the harpooning statue.

The other artifacts are a statue of Queen Nefertiti making an offering, the sandstone head of an Amarna princess, a stone statuette of a scribe from Amarna, and 11 wooden statuettes plus a heart scarab (a protective amulet for the heart) belonging to Yuya, King Tut's great-grandfather.

Hawass stated that an investigation has begun to find the people who have taken the objects, with the police and army planning to follow up with criminals already in custody.

He added that "in another terrible turn of events, on the night of 11 February, 2011 a magazine in Dahshur was broken into."

Called called De Morgan's, the magazine contains large blocks and small artifacts.

"I have said if the Egyptian Museum is safe, then Egypt is safe. However, I am now concerned Egypt is not safe," Hawass said.

Egyptologists and archaeologists have reacted with sadness and disconcert to the announcement, which comes after a series of reassuring statements.

"Just a few days ago it was stated that the museum was safe and everything could be easily restored. Now official sources say that some priceless artifacts have been stolen and others are impossible to restore," Daniele Salvoldi, a doctoral candidate in Egyptology at the University of Pisa, Italy, told Discovery News.

Read more at Discovery News

World’s Total CPU Power: One Human Brain

How much information can the world transmit, process, and store? Estimating this sort of thing can be a nightmare, but the task can provide valuable information on trends that are changing our computing and broadcast infrastructure. So a pair of researchers have taken the job upon themselves and tracked the changes in 60 different analog and digital technologies, from newsprint to cellular data, for a period of over 20 years.

The trends they spot range from the expected—Internet access has pushed both analog and digital phones into a tiny niche—to the surprising, such as the fact that, in aggregate, gaming hardware has always had more computing power than the world’s supercomputers.

The authors were remarkably thorough. For storage media, they considered things like paper, film, and vinyl records, and such modern innovations as Blu-ray discs and memory cards. To standardize their measurements across media, they used Shannon’s information theory to consider data storage in terms of optimally compressed bits. They also tracked technology, noting that in the year 2000, bits of video were compressed using cinepak, which was far less efficient than the current MPEG-4 format; calculations were adjusted accordingly.

Even so, there are some significant estimations here. “For example,” the authors note, “after normalization on optimally compressed bits we can say things like ‘a 6 square-cm newspaper image is worth a 1,000 words.’”

Similar sorts of estimates are required for things like broadcast capability and two-way communications, both of which are compiled as bits-per-second figures. The researchers estimate typical consumption of broadcast media to figure out how much of the existing capacity is used, and they figure that, since telecom equipment is run to maximize the use of its capacity, it’s usually booked to close to its limit.

Read more at Wired

Everything You Wanted to Know About Dinosaur Sex Read

How did these dinosaurs—bristling with spikes and plates—go about making more dinosaurs without skewering each other?

Stegosaurus has become an icon of the mystery surrounding dinosaur sex. Dinosaurs must have mated, but just how they did so has puzzled paleontologists for more than 100 years. Lacking much hard evidence, scientists have come up with all kinds of speculations: In his 1906 paper describing Tyrannosaurus rex, for instance, paleontologist Henry Fairfield Osborn proposed that male tyrant dinosaurs used their minuscule arms for “grasping during copulation.” Others forwarded similar notions about the function of the thumb-spikes on Iguanodon hands. These ideas eventually fell out of favor—perhaps due to embarrassment as much as anything else—but the question remained. How can we study the sex lives of animals that have been dead for millions upon millions of years?

Read the full article over at Smithsonian Mag

If you are particularly interested in animal sex there’s an interesting exhibition featuring plenty of erotic taxidermy over at The Natural History Museum.