Tooth study prompts rethink of human evolution

A study into tooth wear in a group of wild Japanese macaques has significant implications for the study of human evolution, a University of Otago study has shown.

Lead author Dr Ian Towle and Dr Carolina Loch, of the Sir John Walsh Research Institute, in collaboration with colleagues from Japan, studied root grooves and large uniform scratches in the macaques' teeth, which had previously only been described in fossil humans.

"Unusual wear on our fossil ancestors' teeth is thought to be unique to humans and demonstrates specific types of tool use. These types of wear have also been considered some of the earliest evidence of cultural habits for our ancestors," Dr Towle says.

"However, our research suggests this idea may need reconsidering, since we describe identical tooth wear in a group of wild monkeys that do not use tools.

"This research raises questions for our understanding of cultural changes during human evolution and suggests we may need to reassess early evidence of cultural habits."

The study, published in the American Journal of Biological Anthropology, concluded the 'toothpick'-like grooves on back teeth and large uniform scratches on the macaques' front teeth were actually caused by something more mundane, yet still surprising -- eating shellfish from rocks and accidentally chewing grit and sand with their food.

This macaque group is well-known for undertaking remarkable behaviours, including washing foods in water, and consuming fish. They have been studied for more than 70 years and have not been seen using tools or other items that could cause the unusual tooth wear observed.

Dr Towle has been studying tooth wear and pathologies in a wide variety of primate species and was "extremely surprised" to find this type of tooth wear in a group of wild monkeys.

"Up until now, the large scratches in the front teeth of fossil humans have been considered to be caused by a behaviour called 'stuff and cut', in which an item such as an animal hide is held between the front teeth and a stone tool is used for slicing. Similarly, 'toothpick' grooves are thought to be caused by tools being placed between back teeth to remove food debris or relieve pain.

"Although this does not mean hominins were not placing tools in their mouths, our study suggests the accidental ingestion of grit and/or normal food processing behaviours could also be responsible for these atypical wear patterns."

Dr Towle believes the findings provide insight into how researchers interpret cultural changes through the course of human evolution.

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Mummification in Europe may be older than previously known

Mummification of the dead probably was more common in prehistory than previously known. This discovery is made at the hunter-gatherer burial sites in the Sado Valley in Portugal, dating to 8,000 years ago. A new study, headed by archaeologists at Uppsala University and Linnaeus University in Sweden and University of Lisbon in Portugal, presents new evidence for pre-burial treatments such as desiccation through mummification, which has not been suggested for the European Mesolithic before. The results are now published in European Journal of Archaeology.

Until now, the oldest cases of intentional mummification were known from the Chinchorro hunter-gatherers living in the coastal region of the Atacama Desert in northern Chile with examples of mummified bodies buried in shell middens around 7,000 years ago still preserving soft tissue. However, most surviving mummies worldwide are more recent, dating between a few hundred years and 4,000 years old.

Mummification in prehistory is a challenging topic for researchers because it is difficult to detect if a body was preserved through mummification when soft tissue is no longer visible. An additional difficulty is the lack of written reports for these early periods. Unlike bone, finding soft tissue in archaeological sites is rare due to issues of preservation, and without it, it is difficult to recognize if the remains have been curated soon after death. This is particularly challenging in temperate and wetter climates, such as in most of Europe, where soft tissues and fabrics do not normally survive in archaeological sites.

Using recently discovered photographs of the skeletal remains of thirteen individuals excavated in the 1960s in the Sado Valley Mesolithic shell middens in Portugal, the researchers were able to reconstruct the positions in which the bodies were buried providing a unique opportunity to learn more about mortuary rituals taking place 8,000 years ago.

The study combined the approach of archaeothanatology with human decomposition experiments. Archaeothanatology is an approach used by archaeologists to document and analyse human remains in archaeological sites that combines observations of the spatial distribution of the bones in the grave with knowledge about how the human body decomposes after death. Archaeologists can then reconstruct how the dead body was handled after death and buried, even if several millennia have passed. In this study, the archaeothanatology was also informed by results from human decomposition experiments on mummification and burial at the Forensic Anthropology Research Facility at Texas State University.

Based on the results from the experiments, an observable signature for a mummy could be proposed that combines several observations: a hyperflexion of the limbs, an absence of disarticulation in significant parts of the skeleton, and a rapid infilling of sediment around the bones. These were all clearly present in at least one of the burials in this study. The analysis showed that some bodies were buried in extremely flexed positions with the legs flexed at the knees and placed in front of the chest.

During decomposition, the bones usually become disarticulated at weak joints, such as at the feet, but in these cases, the articulations were maintained. The researchers propose that this pattern of hyperflexion and lack of disarticulation could be explained if the body was not placed in the grave as a fresh cadaver, but in a desiccated state as a mummied corpse. Desiccation not only maintains some of these otherwise weak articulations, but also allows for a strong flexion of the body since the range of movement increases when the volume of soft tissue is smaller. Because the bodies were desiccated before burial, there is very little or no sediment present between the bones and the articulations are maintained by the continuous infilling of the surrounding soil supporting the bones and preventing the collapse of the articulations.

The researchers suggest that the observed patterns could be the product of a guided natural mummification process. The manipulation of the body during mummification would have taken place over an extended period of time, during which the body gradually would become desiccated to maintain its bodily integrity, and simultaneously contracted by trussing with rope or bandages to compress it into a desired position. When the process was finished, the body would have been easier to transport (being more contracted and significantly lighter than the fresh cadaver) while ensuring that it was buried while retaining its appearance and anatomical integrity.

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New species of stegosaur is oldest discovered in Asia, and possibly the world

Relatively small, but fearsome-looking stegosaur measured about 2.8 metres (9 feet) from nose to tail -- but scientists can't tell whether the remains are those of an adult or juvenile.

A new species of one of the most recognisable types of dinosaur is the oldest stegosaur ever found in Asia, and one of the earliest unearthed anywhere in the world, according to research published today in the peer-reviewed Journal of Vertebrate Paleontology.

Remains of the stegosaur, which included bones from the back, shoulder, thigh, feet, and ribs, as well as several armour plates, date to the Bajocian stage of the Middle Jurassic period -- much earlier than most known stegosaurs.

A team from the Chongqing Bureau of Geological and Mineral Resource Exploration and Development in China and London's Natural History Museum named it Bashanosaurus primitivus - "Bashan" in reference to the ancient name for the area of Chongqing in China where the dinosaur was found, and the Latin for 'first' -- primitivus.

The new dinosaur, which roamed the planet 168 million years ago, plays a part in uncovering how the stegosaurs evolved -- of which, to this day, little is known.

It has a smaller and less developed should blade, narrower and thicker bases to its armour plates and other features that are different from all other Middle Jurassic stegosaurs discovered so far. However, it does have similarities with some of the first armoured dinosaurs, which are over 20 million years older.

"All these features are clues to the stegosaurs' place on the dinosaur family tree," says Dr Dai Hui from Chongqing Bureau of Geological and Mineral Resource Exploration and Development who led the research. "Bashanosaurus can be distinguished fromother Middle Jurassic stegosaurs, and clearly represents a new species.

"What's more, our analysis of the family tree indicates that it is one of the earliest-diverging stegosaurs along with the Chongqing Lizard (Chungkingosaurus) and Huayangosaurus. These were all unearthed from the Middle to Late Jurassic Shaximiao Formation in China, suggesting that stegosaurs might have originated in Asia," adds Hui.

Instantly recognisable by the huge back plates, long tail spikes and tiny head, stegosaurs were four-legged, plant-eating dinosaurs that lived during the Jurassic and early Cretaceous periods. Stegosaur fossils have been found on all continents except for Antarctica and Australia, and 14 species of stegosaur have been identified so far.

Well-known members of Stegosauria include Huayangosaurus (one of the most primitive stegosaurs), Gigantspinosaurus, notable for its enormous shoulder spines, and Miragaia for its extremely long neck. However, the fragmentary fossil material has hindered attempts to understand how the stegosaurs evolved and how they relate to one another.

With the discovery of this new species the mystery has started to clear up. Bashanosaurus primitivus has several primitive features that are similar to the earliest stegosaurs like Huayangosaurus and Gigantspinosaurus and early-branching thyreophorans (armoured dinosaurs). These include longer tail vertebrae, a shoulder blade that is narrower and flares out, and features of the back vertebrae that are similar to the early armoured dinosaur Scelidosaurus, which lived during the Early Jurassic.

The fossilised remains of Bashanosaurus also reveal a host of features that make it unique from other known stegosaurs. For example, the bony point at the end of the shoulder blade is small and less well developed than in other stegosaurs; a bony projection of the thighbone (fourth trochanter) is positioned below the middle of the shaft; and the bases of the armour plates curve outwards and are thicker than the plates on the backs of its later relatives.

"The discovery of this stegosaur from the Middle Jurassic of China adds to an increasing body of evidence that the group evolved in the early Middle Jurassic, or perhaps even in the Early Jurassic, and as such represent some of the earliest known bird-hipped dinosaurs," says Dr Susannah Maidment, co-author and palaeontologist at London's Natural History Museum.

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More alcohol, less brain: Association begins with an average of just one drink a day

 Even light-to-moderate drinking is associated with harm to the brain, according to a new study. Researchers analyzed data from more than 36,000 adults that found a link between drinking and reduced brain volume that begins at an average consumption level of less than one alcohol unit a day -- the equivalent of about half a beer -- and rises with each additional drink.

The research, using a dataset of more than 36,000 adults, revealed that going from one to two drinks a day was linked with changes in the brain equivalent to aging two years. Heavier drinking was associated with an even greater toll. The science on heavy drinking and the brain is clear: The two don't have a healthy relationship. People who drink heavily have alterations in brain structure and size that are associated with cognitive impairments.

But according to a new study, alcohol consumption even at levels most would consider modest -- a few beers or glasses of wine a week -- may also carry risks to the brain. An analysis of data from more than 36,000 adults, led by a team from the University of Pennsylvania, found that light-to-moderate alcohol consumption was associated with reductions in overall brain volume.

The link grew stronger the greater the level of alcohol consumption, the researchers showed. As an example, in 50-year-olds, as average drinking among individuals increases from one alcohol unit (about half a beer) a day to two units (a pint of beer or a glass of wine) there are associated changes in the brain equivalent to aging two years. Going from two to three alcohol units at the same age was like aging three and a half years. The team reported their findings in the journal Nature Communications.

"The fact that we have such a large sample size allows us to find subtle patterns, even between drinking the equivalent of half a beer and one beer a day," says Gideon Nave, a corresponding author on the study and faculty member at Penn's Wharton School. He collaborated with former postdoc and co-corresponding author Remi Daviet, now at the University of Wisconsin-Madison, and Perelman School of Medicine colleagues Reagan Wetherill -- also a corresponding author on the study -- and Henry Kranzler, as well as other researchers.

"These findings contrast with scientific and governmental guidelines on safe drinking limits," says Kranzler, who directs the Penn Center for Studies of Addiction. "For example, although the National Institute on Alcohol Abuse and Alcoholism recommends that women consume an average of no more than one drink per day, recommended limits for men are twice that, an amount that exceeds the consumption level associated in the study with decreased brain volume,"

Ample research has examined the link between drinking and brain health, with ambiguous results. While strong evidence exists that heavy drinking causes changes in brain structure, including strong reductions in gray and white matter across the brain, other studies have suggested that moderate levels of alcohol consumption may not have an impact, or even that light drinking could benefit the brain in older adults.

These earlier investigations, however, lacked the power of large datasets. Probing massive quantities of data for patterns is the specialty of Nave, Daviet, and colleagues, who have conducted previous studies using the UK Biobank, a dataset with genetic and medical information from half a million British middle-aged and older adults. They employed biomedical data from this resource in the current study, specifically looking at brain MRIs from more than 36,000 adults in the Biobank, which can be used to calculate white and gray matter volume in different regions of the brain.

"Having this dataset is like having a microscope or a telescope with a more powerful lens," Nave says. "You get a better resolution and start seeing patterns and associations you couldn't before."

To gain an understanding of possible connections between drinking and the brain, it was critical to control for confounding variables that could cloud the relationship. The team controlled for age, height, handedness, sex, smoking status, socioeconomic status, genetic ancestry, and county of residence. They also corrected the brain-volume data for overall head size.

The volunteer participants in the Biobank had responded to survey questions about their alcohol consumption levels, from complete abstention to an average of four or more alcohol units a day. When the researchers grouped the participants by average-consumption levels, a small but apparent pattern emerged: The gray and white matter volume that might otherwise be predicted by the individual's other characteristics was reduced.

Going from zero to one alcohol units didn't make much of a difference in brain volume, but going from one to two or two to three units a day was associated with reductions in both gray and white matter.

"It's not linear," says Daviet. "It gets worse the more you drink."

Even removing the heavy drinkers from the analyses, the associations remained. The lower brain volume was not localized to any one brain region, the scientists found.

To give a sense of the impact, the researchers compared the reductions in brain size linked with drinking to those that occur with aging. Based on their modeling, each additional alcohol unit consumed per day was reflected in a greater aging effect in the brain. While going from zero to a daily average of one alcohol unit was associated with the equivalent of a half a year of aging, the difference between zero and four drinks was more than 10 years of aging.

In future work, the authors hope to tap the UK Biobank and other large datasets to help answer additional questions related to alcohol use. "This study looked at average consumption, but we're curious whether drinking one beer a day is better than drinking none during the week and then seven on the weekend," Nave says. "There's some evidence that binge drinking is worse for the brain, but we haven't looked closely at that yet."

They'd also like to be able to more definitively pin down causation rather than correlation, which may be possible with new longitudinal biomedical datasets that are following young people as they age.

"We may be able to look at these effects over time and, along with genetics, tease apart causal relationships," Nave says.

And while the researchers underscore that their study looked only at correlations, they say the findings may prompt drinkers to reconsider how much they imbibe.

"There is some evidence that the effect of drinking on the brain is exponential," says Daviet. "So, one additional drink in a day could have more of an impact than any of the previous drinks that day. That means that cutting back on that final drink of the night might have a big effect in terms of brain aging."

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Did rapid spin delay 2017 collapse of merged neutron stars into black hole?

When two neutron stars spiral into one another and merge to form a black hole -- an event recorded in 2017 by gravitational wave detectors and telescopes worldwide -- does it immediately become a black hole? Or does it take a while to spin down before gravitationally collapsing past the event horizon into a black hole?

Ongoing observations of that 2017 merger by the Chandra X-ray Observatory, an orbiting telescope, suggests the latter: that the merged object stuck around, likely for a mere second, before undergoing ultimate collapse.

The evidence is in the form of an X-ray afterglow from the merger, dubbed GW170817, that would not be expected if the merged neutron stars collapsed immediately to a black hole. The afterglow can be explained as a rebound of material off the merged neutron stars, which plowed through and heated the material around the binary neutron stars. This hot material has now kept the remnant glowing steadily more than four years after the merger threw material outward in what's referred to as a kilonova. X-ray emissions from a jet of material that was detected by Chandra shortly after the merger would otherwise be dimming by now.

While the excess X-ray emissions observed by Chandra could come from debris in an accretion disk swirling around and eventually falling into the black hole, astrophysicist Raffaella Margutti of the University of California, Berkeley, favors the delayed collapse hypothesis, which is predicted theoretically.

"If the merged neutron stars were to collapse directly to a black hole with no intermediate stage, it would be very hard to explain this X-ray excess that we see right now, because there would be no hard surface for stuff to bounce off and fly out at high velocities to create this afterglow," said Margutti, UC Berkeley associate professor of astronomy and of physics. "It would just fall in. Done. The true reason why I'm excited scientifically is the possibility that we are seeing something more than the jet. We might finally get some information about the new compact object."

Margutti and her colleagues, including first author Aprajita Hajela, who was Margutti's graduate student when she was at Northwestern University before moving to UC Berkeley, report their analysis of the X-ray afterglow in a paper recently accepted for publication in The Astrophysical Journal Letters.

The radioactive glow of a kilonova

Gravitational waves from the merger were first detected on Aug. 17, 2017, by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) and the Virgo collaboration. Satellite- and ground-based telescopes quickly followed up to record a burst of gamma rays and visible and infrared emissions that together confirmed the theory that many heavy elements are produced in the aftermath of such mergers inside hot ejecta that produces a bright kilonova. The kilonova glows because of light emitted during the decay of radioactive elements, like platinum and gold, that are produced in the merger debris.

Chandra, too, pivoted to observe GW170817, but saw no X-rays until nine days later, suggesting that the merger also produced a narrow jet of material that, upon colliding with the material around the neutron stars, emitted a cone of X-rays that initially missed Earth. Only later did the head of the jet expand and begin emitting X-rays in a broader jet visible from Earth.

The X-ray emissions from the jet increased for 160 days after the merger, after which they steadily grew fainter as the jet slowed down and expanded. But Hajela and her team noticed that from March 2020 -- about 900 days after the merger -- until the end of 2020, the decline stopped, and the X-ray emissions remained approximately constant in brightness.

"The fact that the X-rays stopped fading quickly was our best evidence yet that something in addition to a jet is being detected in X-rays in this source," Margutti said. "A completely different source of X-rays appears to be needed to explain what we're seeing."

The researchers suggest that the excess X-rays are produced by a shock wave distinct from the jets produced by the merger. This shock was a result of the delayed collapse of the merged neutron stars, likely because its rapid spin very briefly counteracted the gravitational collapse. By sticking around for an extra second, the material around the neutron stars got an extra bounce that produced a very fast tail of kilonova ejecta that created the shock.

"We think the kilonova afterglow emission is produced by shocked material in the circumbinary medium," Margutti said. "It is material that was in the environment of the two neutron stars that was shocked and heated up by the fastest edge of the kilonova ejecta, which is driving the shock wave."

The radiation is reaching us only now because it took time for the heavy kilonova ejecta to be decelerated in the low-density environment and for the kinetic energy of the ejecta to be converted into heat by shocks, she said. This is the same process that produces radio and X-rays for the jet, but because the jet is much, much lighter, it is immediately decelerated by the environment and shines in the X-ray and radio from the very earliest times.

An alternative explanation, the researchers note, is that the X-rays come from material falling towards the black hole that formed after the neutron stars merged.

"This would either be the first time we've seen a kilonova afterglow or the first time we've seen material falling onto a black hole after a neutron star merger," said co-author Joe Bright, a UC Berkeley postdoctoral researcher. "Either outcome would be extremely exciting."

Chandra is now the only observatory still able to detect light from this cosmic collision. Follow-up observations by Chandra and radio telescopes could distinguish between the alternative explanations, however. If it is a kilonova afterglow, radio emission is expected to be detected again in the next few months or years. If the X-rays are being produced by matter falling onto a newly formed black hole, then the X-ray output should stay steady or decline rapidly, and no radio emission will be detected over time.

Margutti hopes that LIGO, Virgo and other telescopes will capture gravitational waves and electromagnetic waves from more neutron star mergers so that the series of events preceding and following the merger can be pinned down more precisely and help reveal the physics of black hole formation. Until then, GW170817 is the only example available for study.

Read more at Science Daily

New research suggests a causal link between blood group and severe COVID-19

A new study has analysed over 3000 proteins to identify which are causally linked to the development of severe COVID-19. This is the first study to assess such a large number of proteins for their connection to COVID-19. The findings provide insight into potential new targets for approaches to treat and prevent severe COVID-19.

Published in PLOS Genetics and part-funded by the National Institute for Health Research (NIHR) Maudsley Biomedical Research Centre, the study used a genetic tool to screen over 3000 proteins. Researchers identified six proteins that could underlie an increased risk of severe COVID-19 and eight that could contribute to protection from severe COVID-19.

One of the proteins (ABO) that was identified as having a causal connection to the risk of developing severe COVID-19 determines blood groups, suggesting that blood groups play an instrumental role in whether people develop severe forms of the disease.

Co-first author Dr Alish Palmos from Institute of Psychiatry, Psychology & Neuroscience (IoPPN) King's College London said: "We have used a purely genetic approach to investigate a large number of blood proteins and established that a handful have causal links to the development of severe COVID-19. Honing in on this group of proteins is a vital first step in discovering potentially valuable targets for development of new treatments."

Assessing how blood proteins are linked to disease can help understand the underlying mechanisms and identify potential new targets for developing or repurposing drugs. Protein levels can be measured directly from blood samples but conducting this type of research for large numbers of proteins is costly and cannot establish causal direction.

This is where genetics can play a role. Mendelian randomisation, a method of comparing causal relations between risk factors and health outcomes, using large genetic datasets can assess the relationship between genetic variants connected with an exposure (in this case high levels of individual blood proteins) and genetic variants connected with disease outcome (in this case severe COVID-19).

Co-first author Dr Vincent Millischerfrom the Medical University of Vienna explained: "Causality between exposure and disease can be established because genetic variants inherited from parent to offspring are randomly assigned at conception similar to how a randomised controlled trial assigns people to groups. In our study the groups are defined by their genetic propensity to different blood protein levels, allowing an assessment of causal direction from high blood protein levels to COVID-19 severity whilst avoiding influence of environmental effects."

The study considered two incremental levels of severity of COVID-19: hospitalisation and respiratory support or death. Using data from a number of genome-wide association studies the researchers found six proteins that were causally linked to an increased risk of hospitalisation or respiratory support/death due to COVID-19 and eight causally linked to protection against hospitalisation or respiratory support/death.

Analysis showed some distinction in types of proteins linked to hospitalisation and those linked to respiratory support/death, indicating different mechanisms may be at work in these two stages of disease.

The analysis identified that an enzyme (ABO) that determines blood group was causally associated with both an increased risk of hospitalisation and a requirement for respiratory support. This supports previous findings around the association of blood group with higher likelihood of death. Taken together with previous research showing that the proportion of group A is higher in COVID-19 positive individuals, this suggests blood group A is candidate for follow-up studies.

Co-last author Dr Christopher Hübelfrom the IoPPN, King's College London said: "The enzyme helps determine the blood group of an individual and our study has linked it with both risk of hospitalisation and the need of respiratory support or death. Our study does not link precise blood group with risk of severe COVID-19 but since previous research has found that proportion of people who are group A is higher in COVID-19 positive individuals, this suggests that blood group A is more likely candidate for follow-up studies."

Researchers also identified three adhesion molecules as being causally linked to a decreased risk of hospitalisation and requirement of respiratory support. As these adhesion molecules mediate interaction between immune cells and blood vessels this chimes with previous research suggesting that late stage COVID-19 is also a disease involving the linings of blood vessels.

By identifying this suite of proteins, the research has highlighted a number possible targets for drugs that could be used to help treat severe COVID-19. These will need further clinical investigation which can be undertaken as part of the wider COVID-Clinical Neuroscience Study (COVID-CNS) which is investigating the causes behind different aspects of COVID-19.

Gerome Breen, Professor of Genetics at the IoPPN, and co-last author on the paper said: "What we have done in our study is provide a shortlist for the next stage of research. Out of 1000s of blood proteins we have whittled it down to about 14 that have some form of causal connection to the risk of severe COVID-19 and present a potentially important avenue for further research to better understand the mechanisms behind COVID-19 with an ultimate aim of developing new treatments but potentially also preventative therapies."

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Single test for over 50 genetic diseases will cut diagnosis from decades to days

A new DNA test, developed by researchers at the Garvan Institute of Medical Research in Sydney and collaborators from Australia, UK and Israel, has been shown to identify a range of hard-to-diagnose neurological and neuromuscular genetic diseases quicker and more-accurately than existing tests.

'We correctly diagnosed all patients with conditions that were already known, including Huntington's disease, fragile X syndrome, hereditary cerebellar ataxias, myotonic dystrophies, myoclonic epilepsies, motor neuron disease and more,' says Dr Ira Deveson, Head of Genomics Technologies at the Garvan Institute and senior author of the study.

The diseases covered by the test belong to a class of over 50 diseases caused by unusually-long repetitive DNA sequences in a person's genes -- known as 'Short Tandem Repeat (STR) expansion disorders'.

'They are often difficult to diagnose due to the complex symptoms that patients present with, the challenging nature of these repetitive sequences, and limitations of existing genetic testing methods,' says Dr Deveson.

The study, published today in Science Advances, shows that the test is accurate, and allows the team to begin validations to make the test available in pathology services around the world.

A patient who participated in the study, John, first realised something wrong when he experienced unusual problems balancing during a ski lesson.

'It was very worrying having symptoms that, over the years, increased in severity; from being active and mobile to not being able to walk without support. I had test after test for over ten years and absolutely no answers as to what was wrong,' says John, who was eventually diagnosed with a rare genetic disease called CANVAS, which affects the brain.

'It was reassuring to finally confirm my diagnosis genetically, and it's exciting to know that, in the near future, others with these types of conditions will be able to get a diagnosis quicker than I did,' he says.

'For patients like John, the new test will be a game-changer, helping to end what can often be a taxing diagnostic odyssey,' says Dr Kishore Kumar, a co-author of the study and clinical neurologist at the Concord Hospital.

Repeat expansion disorders can be passed on through families, can be life threatening and generally involve muscle and nerve damage, as well as other complications throughout the body.

Quicker, more-accurate diagnosis for patients avoids 'diagnostic odyssey'

Current genetic testing for expansion disorders can be 'hit and miss', says Dr Kumar. 'When patients present with symptoms, it can be difficult to tell which of these 50-plus genetic expansions they might have, so their doctor must decide which genes to test for based on the person's symptoms and family history. If that test comes back negative, the patient is left without answers. This testing can go on for years without finding the genes implicated in their disease. We call this the 'diagnostic odyssey', and it can be quite stressful for patients and their families,' he says.

'This new test will completely revolutionise how we diagnose these diseases, since we can now test for all the disorders at once with a single DNA test and give a clear genetic diagnosis, helping patients avoid years of unnecessary muscle or nerve biopsies for diseases they don't have, or risky treatments that suppress their immune system,' says Dr Kumar.

Although repeat expansion disorders cannot be cured, a quicker diagnosis can help doctors identify and treat disease complications earlier, such as heart issues associated with Friedreich's ataxia.

Scanning for known and novel diseases

Using a single DNA sample, usually extracted from blood, the test works by scanning a patient's genome using a technology called Nanopore sequencing.

'We've programmed the Nanopore device to hone in on the roughly 40 genes known to be involved in these disorders and to read through the long, repeated DNA sequences that cause disease,' he says. 'By unravelling the two strands of DNA and reading the repeated letter sequences (combinations of A, T, G or C), we can scan for abnormally long repeats within the patient's genes, which are the hallmarks of disease.'

'In the one test, we can search for every known disease-causing repeat expansion sequence, and potentially discover novel sequences likely to be involved in diseases that have not yet been described,' says Dr Deveson.

Upscaling to wider use in the next five years

The Nanopore technology used in the test is smaller and cheaper than standard tests, which the team hopes will smooth its uptake into pathology labs. 'With Nanopore, the gene sequencing device has been reduced from the size of a fridge to the size of a stapler, and costs around $1000, compared with hundreds of thousands needed for mainstream DNA sequencing technologies' says Dr Deveson.

The team expects to see their new technology used in diagnostic practice within the next two to five years. One of the key steps towards that goal is to gain appropriate clinical accreditation for the method.

Once accredited, the test will also transform research into genetic diseases, says Dr Gina Ravenscroft, a co-author of the study and a researcher working on rare disease genetics at the Harry Perkins Institute of Medical Research.

Read more at Science Daily

Potato genome decoded

More than 20 years after the first releasse of the human genome, scientists at the Ludwig-Maximilians-Universität München and the Max Planck Institute for Plant Breeding Research in Cologne, have for the first time decoded the highly complex genome of the potato. This technically demanding study lays the biotechnological foundation to accelerate the breeding of more robust varieties -- a goal in plant breeding for many years and an important step for global food security.

When shopping for potatoes on a market today, buyers may well be going home with a variety that was already available more than 100 years ago. Traditional potato varieties are popular. And yet this example also highlights a lack of diversity among the predominant potato varieties. However, that could soon change: researchers in the group of geneticist Korbinian Schneeberger were able to generate the first full assembly of a potato genome. This paves the way for breeding new, robust varieties:

"The potato is becoming more and more integral to diets worldwide including even Asian countries like China where rice is the traditional staple food. Building on this work, we can now implement genome-assisted breeding of new potato varieties that will be more productive and also resistant to climate change -- this could have a huge impact on delivering food security in the decades to come."

Especially the low diversity makes potato plants susceptible to diseases. This can have stark consequences, most dramatically during the Irish famine of the 1840s, where for several years nearly the entire potato crop rotted in the ground, and millions of people in Europe suffered from starvation simply because the single variety that was grown was not resistant to newly emerging tuber blight. During the Green Revolution of the 1950s and 1960s, scientists and plant breeders succeeded in achieving large increases in the yields of many of our major crop staples like rice or wheat. However, the potato has seen no comparable boost, and efforts to breed new varieties with higher yields have remained largely unsuccessful to the current day.

The reason for this is simple but has proven difficult to tackle -- instead of inheriting one copy of every chromosome from both the father and from the mother (as in humans) potatoes inherit two copies of each chromosome from each parent, making them a species with four copies of each chromosome (tetraploid). Four copies of each chromosome also mean four copies of each gene, and this makes it highly challenging and time-consuming to generate new varieties that harbour a desired combination of individual properties; what's more, multiple copies of each chromosome also make the reconstruction of the potato genome a far greater technical challenge than was the case for the human genome.

The researchers have overcome this longstanding hurdle using a simple yet elegant trick. Instead of trying to differentiate the four, often very similar, chromosome copies from each other, Korbinian Schneeberger together with his colleague Hequan Sun and other co-workers circumvented this problem by sequencing the DNA of large numbers of individual pollen cells. In contrast to all other cells, each pollen cell contains only two random copies of each chromosome; this facilitated the reconstruction of the sequence of the entire genome.

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Powerful warm winds seen blowing from a neutron star as it rips up its companion

Using the most powerful telescopes on Earth and in space, a team of astronomers has found for the first time blasts of hot, warm and cold winds from a neutron star whilst it consumes matter from a nearby star. The discovery provides new insight into the behaviours of some of the most extreme objects in the universe.

Low-mass X-ray binaries (LMXBs) are systems containing a neutron star or black hole. They are fuelled by material ripped from a neighbouring star, a process known as accretion. Most accretion occurs during violent eruptions where the systems brighten dramatically. At the same time, some of the material that spirals in is propelled back into space in the form of disc winds and jets.

The most common signs of outflowing material from astronomical objects are associated with "warm" gas. Despite this, only winds of "hot" or "cold" gas have been observed in transient X-ray binaries, until now.

In this new study, a team of researchers from eleven countries, led by the University of Southampton, studied the recent eruption of the X-ray binary known as Swift J1858. They used a combination of telescopes, including NASA's Hubble Space Telescope (HST), the European Space Agency's XMM-Newton satellite, the European Southern Observatory Organisation's Very Large Telescope (VLT) and the Spanish Gran Telescopio Canarias (GTC).

The results, published in the journal Nature, showed persistent signatures of a warm wind at ultraviolet wavelengths occurring at the same time as signatures of a cold wind at optical wavelengths. This is the first time that winds from such a system have been seen across different bands of the electromagnetic spectrum.

Lead author Dr Noel Castro Segura, of the University of Southampton said: "Eruptions like this are rare, and each of them is unique. Normally they are heavily obscured by interstellar dust, which makes observing them really difficult. Swift J1858 was special, because even though it is located on the other side of our galaxy, the obscuration was small enough to allow for a full multiwavelength study."

"Only one other system -- the black hole X-ray binary, V404 Cyg -- has shown similar properties. However, our attempt to perform the same experiment on that system was unsuccessful, because the eruption ended before we could get the ground-based and space-based telescopes to observe it simultaneously," co-Author Dr Hernández Santisteban from University of St Andrews said.

Swift J1858 is a newly discovered X-ray transient event that displays extreme variability across the electromagnetic spectrum, which presented a rare opportunity.

"All the astronomers in the field were incredibly excited, to the point that we combined our efforts to cover the full spectrum, from radio to X-ray using state-of-art observatories on Earth and in space," Dr Castro Segura continued.

Co-author Nathalie Degenaar, from the University of Amsterdam added, "Neutron stars have an immensely strong gravitational pull that allows them to gobble up gas from other stars. The stellar cannibals are, however, messy eaters and much of the gas that neutron stars pull towards them is not consumed, but flung into space at high speed. This behaviour has a large impact both on the neutron star itself, and on its immediate surroundings. In this paper we report on a new discovery that provides key information about the messy eating patterns of these cosmic cookie monsters."

"This time we had cosmic luck on our side, as we were able to co-ordinate ten telescopes and point them towards the J1858, all while it was fully active. This allows us to obtain much more information, since we can use different techniques at different wavelengths," Dr Hernández Santisteban said.

Dr Degenaar added, "designing such an ambitious observing campaign -- built around the best telescopes on Earth and in space -- was a huge challenge. So, it is incredibly exciting that all this work has paid off and allowed us to make a key discovery that would not have been possible otherwise."

As well as discovering the different types of winds, the team were able to study the temporal evolution of the gas that flows out. They found that the warm wind was not affected by the strong variations in the brightness of the system. The absence of such a response had previously been an unconfirmed theoretical prediction based on sophisticated simulations.

"In this research we combined the unique capabilities of the HST with the best ground-based telescopes, such as the VLT and GTC, to obtain a complete picture of the dynamics of the gas in the system, from the near-infrared to ultraviolet wavelengths. This allowed us to unveil for first time the true nature of these powerful outflows," Dr Castro Segura said.

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Dark energy: Neutron stars will tell us if it's only an illusion

A huge amount of mysterious dark energy is necessary to explain cosmological phenomena, such as the accelerated expansion of the Universe, with Einstein's theory. But what if dark energy was just an illusion and general relativity itself had to be modified? A new SISSA study, published in Physical Review Letters, offers a new approach to answer this question. Thanks to huge computational and mathematical effort, scientists produced the first simulation ever of merging binary neutron stars in theories beyond general relativity that reproduce a dark- energy like behavior on cosmological scales. This allows the comparison of Einstein's theory and modified versions of it, and, with sufficiently accurate data, may solve the dark energy mystery.

For about 100 years now, general relativity has been very successful at describing gravity on a variety of regimes, passing all experimental tests on Earth and the solar system. However, to explain cosmological observations such as the observed accelerated expansion of the Universe, we need to introduce dark components, such as dark matter and dark energy, which still remain a mystery.

Enrico Barausse, astrophysicist at SISSA (Scuola Internazionale Superiore di Studi Avanzati) and principal investigator of the ERC grant GRAMS (GRavity from Astrophysical to Microscopic Scales) questions whether dark energy is real or, instead, it may be interpreted as a breakdown of our understanding of gravity. "The existence of dark energy could be just an illusion," he says, "the accelerated expansion of the Universe might be caused by some yet unknown modifications of general relativity, a sort of 'dark gravity'."

The merger of neutron stars offers a unique situation to test this hypothesis because gravity around them is pushed to the extreme. "Neutron stars are the densest stars that exist, typically only 10 kilometers in radius, but with a mass between one or two times the mass of our Sun," explains the scientist. "This makes gravity and the spacetime around them extreme, allowing for abundant production of gravitational waves when two of them collide. We can use the data acquired during such events to study the workings of gravity and test Einstein's theory in a new window."

In this study, published in Physical Review Letters, SISSA scientists in collaboration with physicists from Universitat de les Illes Balears in Palma de Mallorca, produced the first simulation of merging binary neutron stars in theories of modified gravity relevant for cosmology: "This type of simulations is extremely challenging," clarifies Miguel Bezares, first author of the paper, "because of the highly non-linear nature of the problem. It requires a huge computational effort -months of run in supercomputers -- that was made possible also by the agreement between SISSA and CINECA consortium as well as novel mathematical formulations that we developed. These represented major roadblocks for many years till our first simulation."

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