Law human: May 2015

Tuesday, May 26, 2015

Ancient DNA suggests dogs split from wolves 40,000 years ago

Man's best friend may be a very old friend indeed. An analysis of a bone from a newly identified ancient wolf species suggests dogs may have split from wolves as early as 40,000 years ago – with or without being domesticated at the same time.

Exactly when dogs started to be domesticated and split from wolves is a matter of some controversy. Archaeological evidence analysing the shapes of canid skulls found near early human camps suggested it might have happened as far back as 35,000 years ago. DNA analysis, focusing on differences between living dog and wolf genomes, seemed to suggest they must have split much more recently – between 11,000 and 16,000 years ago.

Now Love Dalén from the Swedish Museum of Natural History in Stockholm and colleagues have sequenced the genome of a wolf that lived 35,000 years ago in Taimyr, northern Russia, according to carbon dating. This allowed them to recalibrate the molecular clock – the rate at which genetic differences accumulate over time – and better reconstruct the wolf-dog evolutionary tree.

They found that dogs and wolves must have split into two separate lineages 27,000 to 40,000 years ago, bringing the DNA and archaeological evidence into line with each other.

They also found that some northern latitude dog breeds, having split from wolves, then interbred with the now extinct Taimyr wolf, which could have helped them adapt to the challenging northern environment. These breeds include the husky, Greenland sledge dog and, to a lesser extent, the Chinese shar pei and Finnish spitz.

But although the findings back an early split of dogs from wolves, they don't tell us when the domestication of dogs started. "The present study does not rule out the possibility of a very early date indeed, but it does not rule the possibility of a much later date either," says Laurent Frantz from the University of Oxford.

Perhaps humans didn't domesticate dogs once the creatures had split away from wolves: the alternative possibility is that there was an early split between two types of wolves, and that dogs emerged much later on one of these lineages. "We do not yet know whether it infers an early divergence between two wolf populations or between wolves and dogs," says Frantz.

Dalén says a combination of genomic and morphological work on ancient wolf or dog specimens is needed before we have a conclusive date on the time of domestication.

Mietje Germonpre of the Royal Belgian Institute of Natural Sciences in Brussels was one of the researchers who did the skull-shape work that suggested an early date of domestication. She is excited by the new findings, and says she is already studying a lot more specimens that should help clarify the question.

"I find it interesting that early modern humans might have been so resourceful that they started making use of dogs already during the height of the last Ice Age," says Dalén.

Journal reference: Current Biology, DOI: 10.1016/j.cub.2015.04.019

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Forget colour overlays – dyslexia is not a vision problem

A new study has discredited the theory that dyslexia is caused by visual problems. So what does cause the condition and how can it be treated?

What kind of visual problems are claimed to cause dyslexia?
A huge variety. They include difficulties in merging information from both eyes, problems with glare from white pages or the text blurring or "dancing" on the page. A host of products claim to relieve this so-called visual stress, especially products that change the background colour of the page, such as tinted glasses and coloured overlays.

Others advise eye exercises that supposedly help people with dyslexia track words on the page. Despite lack of evidence that these approaches work, some people with dyslexia say they help – more than half of university students with dyslexia have used such products.

What are the new findings?
That there's no evidence visual stress is linked with dyslexia. Nearly 6000 UK children aged between 7 and 9 had their reading abilities tested as well as performing a battery of visual tests. About 3 per cent of them had serious dyslexia, in line with the national average. But in the visual tests, the differences between the students with and without dyslexia were minimal. In two of the 11 tests, about 16 per cent of the children with dyslexia scored poorly, compared with 10 per cent for children with normal reading abilities. But that small difference could be caused by the fact that they read less, says author Alexandra Creavin of the University of Bristol, UK. And more importantly, the 16 per cent figure is so low, it can't be the main explanation for dyslexia.

So what does cause dyslexia?
We don't know. Various ideas have been put forward to explain why some children of normal or above-average intelligence have difficulty learning to read, but none of these theories have become generally accepted. Brendan Barrett of the University of Bradford in the UK says it may be more helpful to regard the condition as an unexplained difficulty with reading that doesn't necessarily reflect someone's intelligence. Many in the field now prefer the term "reading impairment" to avoid the unproven claims about dyslexia. "The term has a lot of baggage," says Barrett.

But those affected by the condition may have been written off as stupid, so appreciate having dyslexia as their "diagnosis".

How should we be treating the condition?
Evidence suggests that the best methods for helping people with dyslexia are the same as those that help anyone learn to read. The old-fashioned "phonics" method teaches individual letter sounds, then how to blend them together into words. People with dyslexia may just need a lot more of this kind of tuition than others. "But if you're spending time on eye exercises, that might be time not spent on phonics," says Creavin.

Who is pushing the coloured overlays?
There's a whole industry based on the visual stress theory, selling not only glasses and overlays but also consultations that can cost hundreds of pounds. "Families are very keen to help their children," says Cathy Williams, who also took part in the study. "There's a belief that in order to do right by their children, they must get hold of these products."

But dyslexia charities also need to be more sceptical, says Williams. A survey last year found that six out of eight UK dyslexia organisations were promoting such products on their websites uncritically and some general health websites accept their value. In a review for the UK's College of Optometrists, Barrett found that coloured overlays were not supported by evidence. But he says he has seen enough people who find them helpful to keep an open mind.

Journal reference: Pediatrics , DOI: 10.1542/peds.2014-3622

Santa Barbara's oil-slicked waters

(Image: Brian van der Brug/Los Angeles Times via Getty Images)

This aerial photo shows part of Santa Barbara's coastline in California, after an estimated 21,000 gallons of oil spewed into the Pacific Ocean on Tuesday.

Taken on Wednesday, oil-soaked kelp darkened the water as efforts to mop up the spill continued.

The cause was a burst pipe, which leaked for 3 hours and released more than 100,000 gallons of oil in that time. Most of it remained on land, spreading across roughly 6.5 kilometres of beach, but enough leaked into the sea to form a 14-kilometre slick.

Many are concerned about the harm it will do to the area's wildlife, which includes whales and sea lions. Dead animals found so far include this oil-covered lobster.

(Image: David McNew/Getty Images)

The same area suffered a devastating spill in 1969, when a platform blowout released hundreds of thousands of gallons of oil into the sea, killing thousands of marine mammals and seabirds.

In the struggle to limit the damage this time, more than 300 people have been involved in clean-up efforts so far. Volunteers have been helping a crew of workers involved in cleaning the beach by raking and vacuuming up oil, and vessels have been deployed to remove oil from the sea surface.

(Image: ZUMA/REX_Shutterstock)

Zoologger: Musical spider purrs like a cat to attract mates

Species: Gladicosa gulosa
Habitat: Leaf litter of beech-maple forests in the east of the US and Canada

With a sound like a wad of money being quietly thumbed, it's hardly a Handel aria.

But for the purring wolf spider, it's music. For the first time, a spider has been recorded producing what appear to be audible courtship signals over and above pure vibrations.

"It's very quiet, but it's what you would hear if you were in the room with a courting spider," says George Uetz of the University of Cincinnati in Ohio, who discovered the purring wolf spider with colleague Alexander Sweger. "The sound is at a level that's audible by human hearing at about a metre away."

Many spider species rely heavily on vibrations to send signals Movie Camera to one another, by shaking leaves or strands of their webs, for example.

Thrum away

But the purring wolf spider is different. While using their pedipalps – the appendages next to their mouthparts – to vibrate dead leaves, they also create an audible thrumming sound. Click here to listen to the spider.

The discovery is a puzzle, as spiders aren't known to have anything equating to "ears".

To check that the "thrum" isn't a bog-standard vibration signal, Uetz and Sweger used a vibration detector called a laser Doppler vibrometer to detect the drumming of the spider and convert it into an audible "sound" output.

Then they used a standard microphone to pick up the audible sound produced at the same time. Comparing the two showed that the vibration and the thrumming sound were two separate emanations.

The pair also found that males produce the sound and only females respond to a played recording of the purr, suggesting that the purr is used in courtship.

"We have yet to see any evidence of any male-to-male communication in this species," says Uetz.

Sensitive spiders

The males only produce the sounds if they are standing on something that will vibrate, like a leaf, and females only respond when perched on a similar surface.

Uetz and Sweger think that the signal reaches the female by travelling as sound in air, which causes the leaves a female is standing on to vibrate.

"We think that's how she 'hears' the sound," says Sweger. "Spiders have very sensitive structures all over their bodies for detecting vibration, even at low levels, so we're working on the hypothesis that they detect a surface vibration induced by the airborne sound."

The purring spiders may help us better understand how communication by sound first evolved. "Animal acoustic signals may originally have evolved from vibration, and our findings suggest a possible mechanism," says Sweger.

The pair reported their findings today at the annual meeting of the Acoustical Society of America in Pittsburgh, Pennsylvania.

These sparkly sea organisms are an eerie omen of climate change

(Image: Jo Malcomson)

"All I can say is wow, just freakin wow!" says Lisa-Ann Gershwin from Australian Marine Stinger Advisory Services in Launceston, Australia.

This river in Southern Tasmania seemed to come alive this week as a bloom of Noctiluca scintillans – a type of bioluminescent plankton, also known as "sea sparkle" – washed into the region.

When it's disturbed, the organism produces light in its cytoplasm, the gel-like substance inside its single cell.

As news of the bloom spread, hundreds of people came to see the spectacle, says Gershwin. "People turned out in droves, rolled up their pant legs and danced, ran, splashed, stomped, tiptoed, you name it, people played! It was incredible!"

But there is a dark side to this impromptu festival of light. "The displays are a sign of climate change," says Anthony Richardson from the CSIRO, Australia's national science agency in Brisbane.

Until 1994, Noctiluca had not been seen in Tasmania. But global warming has been strengthening the East Australian current, which pushes warm water south towards Tasmania. "As the Southern Ocean warms, it will be warm enough for Noctiluca to survive," says Richardson.

What's more, these particular plankton have more direct impacts too. "Noctiluca is a voracious feeder on diatoms, which is the food for krill in the Southern Ocean," says Gustaaf Hallegraeff from the University of Tasmania in Hobart. Dense blooms like this can therefore starve other organisms, he says. They can also kill fish through oxygen depletion and gill irritation.

"As wondrous and entertaining as Noctiluca is, it is also a species infamous for causing fish kills," says Gerhswin. But what the outcome will be from this particular bloom remains an unresolved question, adds Hallegraeff. "Blooms can disappear within days, leaving essentially no trace."

Saturday, May 16, 2015

First human head transplant could happen in two years

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A radical plan for transplanting a head onto someone else’s body is set to be announced. But is such ethically sensitive surgery even feasible?

IT'S heady stuff. The world's first attempt to transplant a human head will be launched this year at a surgical conference in the US. The move is a call to arms to get interested parties together to work towards the surgery.

The idea was first proposed in 2013 by Sergio Canavero of the Turin Advanced Neuromodulation Group in Italy. He wants to use the surgery to extend the lives of people whose muscles and nerves have degenerated or whose organs are riddled with cancer. Now he claims the major hurdles, such as fusing the spinal cord and preventing the body's immune system from rejecting the head, are surmountable, and the surgery could be ready as early as 2017.

Canavero plans to announce the project at the annual conference of the American Academy of Neurological and Orthopaedic Surgeons (AANOS) in Annapolis, Maryland, in June. Is society ready for such momentous surgery? And does the science even stand up?

The first attempt at a head transplant was carried out on a dog by Soviet surgeon Vladimir Demikhov in 1954. A puppy's head and forelegs were transplanted onto the back of a larger dog. Demikhov conducted several further attempts but the dogs only survived between two and six days.

The first successful head transplant, in which one head was replaced by another, was carried out in 1970. A team led by Robert White at Case Western Reserve University School of Medicine in Cleveland, Ohio, transplanted the head of one monkey onto the body of another. They didn't attempt to join the spinal cords, though, so the monkey couldn't move its body, but it was able to breathe with artificial assistance. The monkey lived for nine days until its immune system rejected the head. Although few head transplants have been carried out since, many of the surgical procedures involved have progressed. "I think we are now at a point when the technical aspects are all feasible," says Canavero.

This month, he published a summary of the technique he believes will allow doctors to transplant a head onto a new body (Surgical Neurology International, doi.org/2c7). It involves cooling the recipient's head and the donor body to extend the time their cells can survive without oxygen. The tissue around the neck is dissected and the major blood vessels are linked using tiny tubes, before the spinal cords of each person are cut. Cleanly severing the cords is key, says Canavero.

The recipient's head is then moved onto the donor body and the two ends of the spinal cord – which resemble two densely packed bundles of spaghetti – are fused together. To achieve this, Canavero intends to flush the area with a chemical called polyethylene glycol, and follow up with several hours of injections of the same stuff. Just like hot water makes dry spaghetti stick together, polyethylene glycol encourages the fat in cell membranes to mesh.

Next, the muscles and blood supply would be sutured and the recipient kept in a coma for three or four weeks to prevent movement. Implanted electrodes would provide regular electrical stimulation to the spinal cord, because research suggests this can strengthen new nerve connections.

When the recipient wakes up, Canavero predicts they would be able to move and feel their face and would speak with the same voice. He says that physiotherapy would enable the person to walk within a year. Several people have already volunteered to get a new body, he says.

The trickiest part will be getting the spinal cords to fuse. Polyethylene glycol has been shown to prompt the growth of spinal cord nerves in animals, and Canavero intends to use brain-dead organ donors to test the technique. However, others are sceptical that this would be enough. "There is no evidence that the connectivity of cord and brain would lead to useful sentient or motor function following head transplantation," says Richard Borgens, director of the Center for Paralysis Research at Purdue University in West Lafayette, Indiana.

If polyethylene glycol doesn't work, there are other options Canavero could try. Injecting stem cells or olfactory ensheathing cells – self-regenerating cells that connect the lining of the nose to the brain – into the spinal cord, or creating a bridge over the spinal gap using stomach membranes have shown promise in helping people walk again after spinal injury. Although unproven, Canavero says the chemical approach is the simplest and least invasive.

But what about the prospect of the immune system rejecting the alien tissue? Robert White's monkey died because its head was rejected by its new body. William Mathews, chairman of the AANOS, says he doesn't think this would be a major problem today. He says that because we can use drugs to manage the acceptance of large amounts of tissue, such as a leg or a combined heart and lung transplant, the immune response to a head transplant should be manageable. "The system we have for preventing immune rejection and the principles behind it are well established."

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Say hello to machines that read your emotions to make you happy

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The latest AI devices can't just gauge your mood from what you say and how you say it, they can work out the best way to respond to cheer you up

"BRIAN? How are you, Brian?" The voice is coming from a screen dominated by a vast blue cartoon eyeball, its pupil dilating in a way that makes it look both friendly and quizzical. Think HAL reimagined by Pixar.

This is EmoSPARK, and it is looking for its owner. Its camera searches its field of view for a face and, settling on mine, asks again if I am Brian. It sounds almost plaintive.

EmoSPARK's brain is a 90-millimetre Bluetooth and Wi-Fi-enabled cube. It senses its world through an internet connection, a microphone, a webcam and your smartphone. Using these, the cube can respond to commands to play any song in your digital library, make posts on Facebook and check for your friends' latest updates, stream a Netflix film, answer questions by pulling information from Wikipedia, and simply make conversation.

But its mission is more complex: EmoSPARK, say its creators, is dedicated to your happiness. To fulfil that, it tries to take your emotional pulse, adapting its personality to suit yours, seeking always to understand what makes you happy and unhappy.

The "Brian" in question is Brian Fitzpatrick, a founding investor in Emoshape, the company that makes EmoSPARK. He and the device's inventor, Patrick Levy Rosenthal, compare EmoSPARK's guiding principles to Isaac Asimov's laws of robotics. They are billing the cube as the world's first "emotional AI".

But EmoSPARK isn't the first robotic agent designed to learn from our emotions. There's Jibo the family Movie Camera robot and Pepper the robot companion. Even Amazon's Echo voice-activated controller might soon be able to recognise emotions.

The drive to give artificial intelligence an emotional dimension is down to necessity, says Rana el Kaliouby, founder of Affectiva, a Boston-based company that creates emotion-sensing algorithms. As everything around us, from phones to fridges, gets connected to the internet, we need a way to temper machine logic with something more human.

And when the user is immersed in a world that is as much computer as real life, a machine must learn some etiquette. For example, you shouldn't come home from a funeral to find your AI itching to tell you about the latest Facebook cat videos.

How can a machine be trained to understand emotions and act on them? When EmoSPARK's webcam finds my face, a red box flashes briefly on screen to indicate it has identified a face that isn't Brian's. Behind the scenes, it is also looking for deeper details.

EmoSPARK senses the user's emotional state with the help of an algorithm that maps 80 facial points to determine, among other things, whether he or she is smiling, frowning in anger or sneering in disgust. EmoSPARK also analyses the user's tone of voice, a long-established method of mood analysis.

Having sensed these details, EmoSPARK uses them to mirror your emotions. First, it creates an emotional profile of its owner based on the combination of facial and voice input. At the end of each day, it sends this information to EmoShape, which sends back a newly tailored emotional profile for that particular device. Through this feedback loop, Fitzpatrick says, the cube's personality changes ever so slightly every day.

Hard problems

Rosalind Picard at the Massachusetts Institute of Technology is sceptical that this can produce an accurate emotional profile. Picard, who designs facial and vocal analysis software to help computers interpret emotion, and co-founded Affectiva with el Kaliouby, says there's more to understanding moods than mapping points on the face. "What does it know about the context? How much data is it trained on? How is it being taught the true feelings of the person? These are still hard problems to solve."

The algorithm used by EmoSPARK isn't necessarily all that sophisticated. Coaxing it to register a user's smile requires a toothy grin in good lighting; real-world conditions, for most people, don't live up to that.

But maybe you don't need a million-dollar algorithm. One aspect of creating "emotional" AI requires neither hardware nor software: it's just a matter of exploiting what our brains do naturally. "We anthropomorphise everything," says Eleanor Sandry at Curtin University in Perth, Australia. Humans project intent and emotions on to anything from dolphins to Microsoft's paper clip. We can't help ourselves.

And EmoSPARK pulls out all the stops to put this tendency to work. To calibrate your cube, you undertake a ritual which ensures that only one person can be emotionally bound to it. "Are you the person I am to bond with?" is its first question. Although it will recognise other individuals in the same house or building, it only creates the emotional profile for its owner.

That doesn't mean it can't interact with anyone else. When someone who is not Brian taunts it, saying "I don't like you", EmoSPARK manifests its displeasure with a pulse of green light that shudders through the cube. "It's funny, I don't like you that much either," it responds. If EmoSPARK had been complimented, it would have glowed purple.

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Zoologger: The clumsy tree-dweller transforms into a gliding ace

Zoologger is our weekly column highlighting extraordinary animals – and occasionally other organisms – from around the world

Species: Malayan flying lemur (Galeopterus variegatus)
Habitat: Rainforests and plantations of South-East Asia

Take one look at a flying lemur, or colugo, sitting in a tree and it brings to mind a scrawny kid forced to wear his big brother's hand-me-downs. Flaps of skin hang around its ankles and get in the way as it clambers awkwardly around the forest.

Once the colugo leaps into the air, though, everything changes. Its baggy folds transform into enormous wings as the animal sails gracefully through the canopy.

With their bark-patterned fur and nocturnal habits, spotting these animals, which are about the size of large squirrels, is tough. This didn't deter Yamato Tsuji of Kyoto University, Japan, and his colleagues, who spent four years in the jungles of Indonesia studying them.

Colugos spend their days curled up in cracks and crevices in the rainforest trees, only emerging to snack on young leaves at night. They are particular about which tree species they sleep in, Tsuji and his team found, and above all favour tall, isolated trees standing high above the canopy.

Here they can hide from predators, such as civets and pythons. But if spotted, the lack of surrounding vegetation makes for a quick and easy getaway. It also gives them a nice launch pad for their dusk departure to feeding trees lower down in the canopy.

These animals are not technically flying, of course, but neither are they lemurs, though they are related. They belong to a family called the Cynocephalidae. The Philippine and Malayan flying lemurs are the only two species in this very exclusive club.

They lack the opposable thumbs of their primate cousins, which partly explains their ungainly, frog-like climbing technique, says Tsuji.

But what they lack in ability on the branches they more than make up for in the air. Colugos are the largest of the gliding mammals, and with an arm span of 70 centimetres, this makes for impressive "wings". Stretching from fingertip to tail tip they are big as physically possible. Even their fingers are webbed to maximise the glider's surface area. This feat of natural engineering allows flying lemurs glide over 130 metres while losing only around 10 metres in height - on a par with flying squirrels and other gliding mammals. During the day, the flaps double up as a cosy shelter for baby colugos as they cling to their mother's belly.

When it comes to landing, colugos have class. Since gliding is little more than falling with style, you might think it would end in a dramatic landing. Not a bit of it. Colugos can adjust their aerodynamics to slow themselves down significantly. Just before landing they angle their body upwards to reduce speed, landing softly on all fours with pinpoint accuracy.

These easy gliders suffer from habitat loss and hunting, but luckily, at the moment their numbers seem to be holding up reasonably well.

Journal reference: Mammal Study, DOI: 10.3106/041.040.0107

Meet the cat-sized rodent named after James Bond

(Image: Jose Nunez-Mino)

The name's Bond. Plagiodontia aedium bondi. It's certainly a name to live up to. A cat-sized rodent newly discovered on the Caribbean island of Hispaniola has been named after James Bond, a real-life naturalist who also gave his name to Ian Fleming's fictional spy.

Found by Samuel Turvey of the Zoological Society of London and his team, the guinea pig-like rodent, which weighs more than a kilogram, is a type of hutia, a family of secretive rodents that live in the West Indian islands. Its name is fitting because the original Bond studied the distribution of hutias and their relatives in the Caribbean.

But the James Bond rodent belongs to a troubled family. Although there were once more than 30 species, most hutia have been driven to extinction by the colonisation of the islands. The newly discovered resident may be one of only eight types of hutia left.

"I am glad we were able to describe James Bond's hutia before it's too late, as it is highly threatened by deforestation, even in protected areas," says Turvey."

Journal reference: Zootaxia, 10.11646/zootaxa.3957.2.4

7 easy ways to reduce the pain you're feeling

Feeling sore? A new study suggests holding your breath can ease the pain of an injury. But this trick only works if you were expecting pain in the first place, so here are seven other easy – and scientifically sound – ways to relieve your suffering the next time you have an unfortunate encounter with a hammer, drawer or door.

1. Reach for the perfume
The sweet scent of roses is enough to cheer anyone up, but pleasant smells also seem to reduce the intensity of a painful stimulus – for women, at least. In a 2002 study, female volunteers had their hands submerged in painfully hot water, and reported less pain when exposed to pleasant aromas, such as flowers or almonds. When asked to sniff vinegar, however, the women's pain got worse. The effect didn't seem to work in male volunteers.

2. Curse like a sailor
If your first response to a stubbed toe is to swear loudly, that's no bad thing, according to research by a team at Keele University, UK. They found that people were better able to deal with the pain of having their hand submerged in icy water when they swore, perhaps because the bad language triggers a hormonal response that lessens pain. Unfortunately it doesn't seem to work so well in people who already swear a lot.

3. Pick a pretty picture
Penchant for Picasso? Boticelli's biggest fan? A team of researchers at the University of Bari in Italy found that showing people pictures they found beautiful reduced the pain they felt when a laser burned their hands, and seemed to reduce activity in the brain regions that normally process pain.

4. Cross your arms
Simply crossing one arm over the other has been found to reduce the perceived intensity of a painful laser to the back of the hand. The researchers behind the study, based at University College London, think that putting your limbs in unfamiliar positions essentially muddles the brain and disrupts the pain signal.

5. Listen to music
It's well known that the right music can heal a broken heart, but it also seems to soothe physical pain. People receiving dental treatment are less likely to ask for anaesthetic if they can watch music videos during the procedure, while people experiencing pain after cancer surgery can cope better if they are played ambient music.

6. Fall in love
It makes the world brighter and food taste better – but being in love can also ease your pain. Just looking at a picture of your loved one can reduce the intensity of holding a painfully hot block. But it has to be real love – pictures of other attractive people don't have any effect.

7. Touch yourself
In 2010, neuroscientists at University College London found that people were better able to withstand increasing heat applied to their fingers when they touched their heated hand with their other hand. The team say that self-touch reduced the perceived level of heat by 64 per cent – perhaps adopting the foetal position during stomach cramps makes sense after all.

Rewiring of senses in a mouse brain revealed in glorious colour

(Image: Andreas Zembrzycki/Salk Institute)

It's easy for a mouse to change its mind, at least when it's very young. Neurons normally responsible for interpreting sound or touch, for example, can swap senses while they are maturing, taking on vision instead. In the brain image above, neurons shown in yellow have been rewired, changing the type of sensory input they are able to process.

Andreas Zembrzycki from the Salk Institute for Biological Studies in La Jolla, California, and his colleagues have shown that a protein called Lhx2, which can change the function of sensory neurons by switching genes on or off, is the key. Previously, it was thought to alter neurons only before birth.

The discovery could lead to ways of treating conditions that involve abnormal brain wiring, such as schizophrenia. It could provide an alternative to current approaches such as neuron transplants which are being investigated to help remedy a range of brain conditions.

Journal reference: PNAS, DOI: 10.1073/pnas.1424440112

Thursday, May 7, 2015

Human gene editing has arrived – here's why it matters

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It's becoming possible to edit our genes to treat and prevent conditions like HIV and sickle cell disease or, more controversially, create designer babies

GENE editing is here. The first work attempting to edit human embryos grabbed headlines last week. And another study showed how gene editing might prevent children inheriting disease.

It could be decades before it is safe to snip out and replace stretches of DNA to genetically engineer babies – even if it is deemed ethically acceptable. But the approach is already being tested for treating disease in adults and could soon be used to treat a wide range of disorders.

It has been a long time coming. Rudimentary editing methods were first developed some 30 years ago, but only now have techniques been honed to the point that they can be used for treating people. It raises the curtain on a new era of genomic tinkering and genetic medicine.

HIV therapy

In the coming months, four US clinics will recruit people with HIV to a trial of a therapy based on gene editing. HIV wreaks havoc by destroying immune cells called T-cells. It does this by exploiting a receptor, CCR5, on the surface of these cells. Destroy the gene for CCR5 and you can block infection.

Last year, researchers targeted and destroyed this gene in the T-cells of 12 people with HIV using custom-made proteins called zinc finger nucleases. This raised their resistance to the virus. The new trial goes further, knocking out the gene in the stem cells that give rise to T-cells, making it a possible one-shot, lasting treatment. "The goal is a functional cure," says John Zaia, of the City of Hope hospital in Duarte, California.

The trial blazes a path for using the approach to treat other diseases. For example, another trial set to start soon will focus on sickle cell disease, in which the oxygen-carrying haemoglobin molecules in red blood cells are abnormal. The technique would switch on a protein that can be used instead of the haemoglobin.

There could be downsides to this approach though. "Genome editing offers both tremendous promise and significant potential risk," says David Liu of Harvard University. Almost all editing techniques have the potential to modify unintended DNA sequences, he says. "Some of these off-target genome modification events will likely lead to negative biological consequences."

But, if it can be made safe, editing adult stem cells is likely to face fewer ethical hurdles than other applications of gene editing.

Inherited change

Some teams are already exploring the possibility of using gene editing to make heritable changes. Last week, researchers showed that gene editing can weed out mutations in the mitochondria that a female mouse passes on to her offspring.

Mitochondria generate energy in our cells and have their own set of DNA, which differs from that in the cell nucleus. Mutations in mitochondria can cause diseases for which there are no treatments.

Earlier this year, the UK gave the green light to mitochondrial replacement therapy. This involves creating "three-parent babies" with healthy mitochondria donated from a third person preventing such diseases being passed on.

The new approach offers an alternative. It uses a gene-editing technique based on custom-made proteins called TALENs. These proteins can be designed to latch on to the DNA in faulty mitochondria and target them for destruction. Healthy mitochondria remain unharmed.

Most women at risk of passing on faulty mitochondria carry some healthy and some mutated mitochondria, so TALENs could lower the number of mutated mitochondria in their eggs. Harmful effects only kick in once the number of mutated mitochondria crosses a threshold, so this may be enough to prevent disease in their child, and perhaps in future generations too.

Using gene editing in this way isn't without risk, says Robert Lightowlers at Newcastle University, UK. It is unclear whether reducing the number of mitochondria could have a long-term effect, he says. And although the TALENs protein in the study seemed to target only the intended mitochondria, it could be harmful if even a very low amount of it got into the nucleus and altered DNA there.

Juan Carlos Izpisua Belmonte of the Salk Institute for Biological Studies in La Jolla, California, who is part of the team doing the TALENs work, says they plan to begin testing the safety of the technique. "The idea will be to obtain oocytes and discarded embryos from IVF treatments in order to test this technology using human samples."

Taking the research to the next level will be controversial. Last month, a group of scientists called for a moratorium on gene editing research in cells that can form embryos. The plea was made by those working on gene editing with adult cells who are concerned that embryo editing could have unpredictable effects on future generations and stimulate a public outcry.

Uncharted waters

Despite the call for a hiatus, a team in China announced last week that it had edited DNA in the nucleus of human embryos.

The work involves a technique called CRISPR/Cas9, developed in the last few years. It has the potential to accelerate progress enormously because CRISPR is much faster than conventional gene editing methods (see "How to edit genes").

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Galactic smash-ups turn on the lights around black holes

Looks like something left the lights on. The supermassive black holes at the cores of some galaxies give off a tremendous amount of light. It comes from superheated discs of gas that slowly spiral into the maws of the black holes, but where all that gas came from has been debated for decades. Now, observations reveal tell-tale signs of debris that suggest ancient galactic crashes flipped the light switch in the brightest of these "active galaxies".

One of the main hypotheses is that the gas could be funnelled towards black holes when colliding galaxies send vast amounts of it toward their shared centre as they merge. But an alternate theory has gained traction recently, especially to explain fainter galaxies. This theory holds that the structure of galaxies becomes unstable over time and causes a self-implosion.

To test which process is more frequent, Jueun Hong and Myungshin Im of Seoul National University in South Korea imaged 39 of these bright active galaxies, with telescopes in Chile, Texas and Uzbekistan. They spent up to four hours on each galaxy to capture fine, faint details. They inspected the images for signs of a past or ongoing merger – wispy trails of stars flung violently into space during an intergalactic pile-up.

Gassy galaxies

The team found that 17 of the galaxies had such features, which was between four and eight times more than they saw in a sample of images of non-active galaxies.

Im says the results show that although both mechanisms could trigger active galaxies, mergers are the main cause for the brightest ones. "You have to have a great amount of gas supply to fuel them," he says.

The study is "a new piece of the puzzle", says Nico Cappelluti of the National Institute of Astrophysics in Bologna, Italy. In 2011, Cappelluti and his colleagues published a study of fainter, more distant active galaxies, and found no signs of collisions. "In this paper they study much brighter sources than ours and in this case, the merger scenario works," he says.

Journal reference: Astrophysical Journal, DOI: 10.1088/0004-637X/804/1/34

Female ejaculation comes in two forms, scientists find

What do you think of when you hear the words "female ejaculation"? Come to think of it, the answer may be best kept to yourself. You may have heard that it was banned from being shown in British porn films last year. But what exactly is it?

Researchers have now come a step closer to defining this controversial phenomenon, by performing the first ultrasound scans on women who express large amounts of liquid at orgasm.

Some women express liquid from their urethra when they climax. For some, this consists of a small amount of milky white fluid – this, technically, is the female ejaculate. Other women report "squirting" a much larger amount of fluid - enough to make it look like they've wet the bed.

A few small studies have suggested the milky white fluid comes from Skene glands - tiny structures that drain into the urethra. Some in the medical community believe these glands are akin to the male prostate, although their size and shape differ greatly between women and their exact function is unknown.

Climax in the lab

To investigate the nature and origins of the fluid, Samuel Salama, a gynaecologist at the Parly II private hospital in Le Chesnay, France, and his colleagues recruited seven women who report producing large amounts of liquid - comparable to a glass of water - at orgasm.

First, these women were asked to provide a urine sample. An ultrasound scan of their pelvis confirmed that their bladder was completely empty. The women then stimulated themselves through masturbation or with a partner until they were close to having an orgasm - which took between 25 and 60 minutes.

A second pelvic ultrasound was then performed just before the women climaxed. At the point of orgasm, the squirted fluid was collected in a bag and a final pelvic scan performed.

Even though the women had urinated just before stimulation began, the second scan - performed just before they climaxed - showed that their bladder had completely refilled. Each woman's final scan showed an empty bladder, meaning the liquid squirted at orgasm almost certainly originated from the bladder.

A chemical analysis was performed on all of the fluid samples. Two women showed no difference between the chemicals present in their urine and the fluid squirted at orgasm.

The other five women had a small amount of prostatic-specific antigen (PSA) present in their squirted fluid - an enzyme not detected in their initial urine sample, but which is part of the "true" female ejaculate

PSA, produced in men by the prostate gland, is more commonly associated with male ejaculate, where its presence helps sperm to swim. In females, says Salama, PSA is produced mainly by the Skene glands.

Beverley Whipple, a neurophysiologist from Rutgers University in Newark, New Jersey, says that the term female ejaculation should only really refer to the production of the small amount of milky white liquid at orgasm and not the "squirting" investigated in this paper. "This study shows the other two kinds of fluids that can be expelled from the female urethra - urine alone, and urine diluted with substances from the female prostate," she says.

"This study presents convincing evidence that squirting in women is chemically similar to urine, and also contains small amounts of PSA that is present in men's and women's true ejaculate," says Barry Komisaruk, also at Rutgers.

"This study helps to reconcile the controversy over the fluids that many women report being released at orgasm," he adds. "There are evidently two different fluids, with two different sources. Whether either of these fluids plays a physiological role - that is, whether they serve any adaptive function, is not known."

Florian Wimpissinger at Rudolfstiftung Hospital in Vienna, Austria, suggests that the presence of PSA in some women's squirted fluid and not others might be because the emissions from the Skene glands could travel into the bladder at orgasm. It may also have something to do with the known variation in size and shape of the glands, or be that some women don't produce PSA in the first place.

Every woman capable

Why some women experience these different types of ejaculation and others don't is not yet clear, says Salama, but he believes every woman is capable of squirting "if their partner knows what they are doing".

For now, Salama is not investigating that particular avenue, but instead working on a protocol to test whether the kidneys work faster to produce urine during sexual stimulation than at other times, and if so, why.

The ban on female ejaculation in UK porn is based on the fact that the British Board of Film Classification (BBFC) considers films which include material featuring "urolagnia" - sexual pleasure associated with urination - as obscene under the UK Obscene Publications Act.

However, the wording of the law actually appears to be referring to squirting - not female ejaculation. So this new paper may support the current legal position, since it shows it is essentially involuntary urination. Presumably, under current UK law, if a woman were to have what is considered a true female ejaculation - the expulsion of a small amount of milky white fluid - and the BBFC were satisfied that this did not contain urea - this act would not be subject to the ban.

Journal reference: The Journal of Sexual Medicine, DOI: 10.1111/jsm.12799

Microbes found at bottom of ocean are our long-lost relatives

SO THAT'S where they've been hiding. An entirely new group of organisms discovered at the bottom of the Arctic Ocean are our closest simple-celled relatives ever found.

Approximately 2 billion years ago, complex eukaryotic cells, which make up animals, plants and fungi, split from smaller, simpler cells called prokaryotes. Researchers have now identified our closest relatives from before this split.

Thijs Ettema at Uppsala University, Sweden, and his team discovered the new organisms when they analysed DNA extracted from underwater sediment near Loki's Castle, a region of hydrothermal vents along the Arctic mid-ocean ridge (Nature, DOI: 10.1038/nature14447).

Named Lokiarchaea, the organisms are a new type of archaea. Like fellow prokaryotic bacteria, archaea lack a true cell nucleus and other complex cell machinery. But intriguingly, the Lokiarchaea appear to have more than 100 genes coding for sophisticated cellular functions such as deforming cell membranes and forming and transporting bubble-like vesicles around the cell – functions that are usually only seen in eukaryotes like us.

"It is a truly remarkable, landmark discovery," says Eugene Koonin at the National Center for Biotechnology Information in Bethesda, Maryland. It suggests that our sophisticated cells could have evolved from special, more elaborate forms of ancient prokaryote.

"We were really blown away when we got the first genome data," says Ettema. "We can now say that the archaeal ancestor of eukaryotes was perhaps already quite complex."

"Ettema's team have certainly thrown the cat among the pigeons," says Anthony Poole at the University of Canterbury in New Zealand. He says that the discovery of Lokiarchaea blurs the lines between archaea and eukaryotes. "It's still 100 per cent archaeon, but the presence of genes we usually associate with eukaryote cell biology is absolutely fascinating."

Ettema's team argue that their finding helps bridge the gap between our cells and those of the typical prokaryotic organisms from which we are believed to have evolved.

Others are more sceptical. "We're getting closer to an archaeal ancestor of the eukaryotes," says Nick Lane of University College London. However, even though the Lokiarchaea are relatively complex compared with other known archaea, they lack the large genome and energy-producing mitochondria of true eukaryotic cells. "It's a thousandth of the way towards the complexity of a eukaryote," says Lane. So we can't really call them an intermediate step or a missing link.

Lane believes the crucial step in the evolution of the eukaryotes was acquiring mitochondria, which would have provided the energy to develop more complicated cellular processes and acquire a larger genome. Ettema does not think the Lokiarchaea have mitochondria, but he says some form of intracellular transport may have evolved before our ancestors acquired their powerhouses.

And while DNA data shows that the Lokiarchaea are our closest known prokaryotic relatives, they may still be very different from the common ancestor that we shared 2 billion years ago.

Unfortunately, we cannot know exactly how the Lokiarchaea use their genes until we can observe one of their cells directly. Ettema's team did not actually see the cells: they used computational methods to piece together the genomes from the DNA found in the seafloor sediment.

Archaea can be particularly difficult to collect and culture in a laboratory, so we may never get a good look at our long-lost prokaryotic cousins.

This article appeared in print under the headline "Long-lost relatives found at bottom of Arctic Ocean"

Spiders sprayed with graphene or carbon nanotubes spin super silk

Spider-Man would be so envious. Spiders have woven webs infused with carbon nanotubes and even graphene, raising the prospect of new materials with record-beating properties.

Graphene – sheets of carbon just one atom thick – is one of the strongest artificial materials, and spider silk is one of the strongest natural ones. So Nicola Pugno of the University of Trento, Italy, wondered what would happen if you combined them.

Pugno and his colleagues captured five spiders from the Pholcidae family and sprayed them with a mixture of water and graphene particles 200 to 300 nanometres wide. They also sprayed another 10 spiders with carbon nanotubes and water to compare the effects of the two materials.

Some spiders produced below-par silk, but others got a major boost. The best fibres came from a spider dosed with nanotubes: it was around 3.5 times as tough and strong as the best unaltered silk, spun by the giant riverine orb spider.

From spiders to silkworms

The only natural material that is stronger than orb spider silk is the material that the teeth of molluscs called limpets are made out of, Pugno and colleagues revealed earlier this year. The molluscs' teeth stretch more than the spider silk, but are much less tough, meaning they crack more easily.

The team isn't sure how the graphene and carbon nanotubes end up in the silk. One possibility is that the carbon coats the outside of the strands, but Pugno thinks that would not be enough to account for the increase in strength. Instead, he believes the spiders mop up materials in their environment and incorporate them into the silk as they spin. This comes at a cost, however – four of the spiders died soon after being sprayed.

At this early stage it's not clear how such a material will be used, but one possibility is a giant net capable of catching falling aircraft, suggests Pugno. The team also plans to investigate other ways of producing bionic materials, such as dosing silkworms with artificial substances. "This concept could become a way to obtain materials with superior characteristics," he says.

Reference: arxiv.org/abs/1504.06751

The human universe: Could we colonise the stars?

It's fun to speculate about aliens (see "The human universe: If aliens exist, do they know we're here?"). But what if there are no aliens? It's been 65 years since Enrico Fermi first pointed out our solitude. Fermi estimated that it would take an advanced technological civilisation 10 million years or so to fill the galaxy with its spawn. Our galaxy is 10,000 times older than that. Where is everybody?

It's not as though we haven't been looking. Not for long, perhaps, and not very hard, but even a crude estimate suggests there should be other advanced civilisations capable of signalling over interstellar distances. And yet – nothing.

So what if we really are alone, or so isolated as to amount to the same thing? "If we think we are the only life in the universe, we have a huge responsibility to spread life to the stars," says Anders ...

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The human universe: Could we destroy the fabric of the cosmos?

How destructive are we? (Image: Sam Chivers

With great power comes great responsibility. As our grip on Earth grows ever tighter, so does the possibility that we could destroy it, or at least ourselves. But the prospect pales into insignificance when you consider that we may have the power to do something even worse.

We could destroy the universe.

Remember the outcry when CERN was getting ready to start smashing particles together in its Large Hadron Collider? A few doomsayers warned that it might be opening the door to the apocalypse.

This existential angst was triggered by the prospect of protons colliding at extremely high energies. Einstein's general theory of relativity suggests that concentrating this kind of energy in a volume smaller than an atom might distort space and time enough to tear a hole in the fabric of the universe. This "mini black hole" could rapidly expand ...

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