Revealed: Coral fights back against crown of thorns starfish

Juvenile reef predator vulnerable to coral stings

UNIVERSITY OF SYDNEY

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VIDEO: ORIGINAL FOOTAGE OF YOUNG CROWN OF THORNS STARFISH AND CORAL INTERACTION view more 

CREDIT: DIONE DEAKER

Coral are not completely defenceless against attacking juvenile crown of thorns starfish and can fight back to inflict at times lethal damage, new research has found.

This occurs during a period of the crown of thorns starfish life cycle, where small juveniles shift from a vegetarian diet of algae to coral prey. But this change in diet makes the juveniles more vulnerable to attack by coral.

Population outbreaks of adult crown of thorns starfish, alongside coral bleaching is one of the greatest threats to tropical reef habitats.

Video footage shows when the tube feet (small tube-like projections on the underside of a starfish's arm used for movement) of juvenile crown of thorns starfish reaches out to touch the coral, the entire arm curls back to avoid the corals' defensive stinging cells. To protect themselves, coral polyps have stinging cells in their sweeper tentacles and outer tissue called nematocysts, that are also used to capture food.

This encounter damages the arms of juvenile crown of thorn starfish, delaying their growth into adulthood. Researchers also saw a 10 percent fatality rate among the juvenile crown of thorns starfish they studied. However, most juveniles that survived arm damage were able to regenerate partially lost arms.

The research, published in Marine Ecology Progress Series, was led by Dione Deaker, a PhD student at the University of Sydney, and her supervisor Professor Maria Byrne. The marine scientists say that this is the first study of injury and regeneration in juvenile crown of thorn starfish following damage caused by natural enemies.

The researchers emphasise the results give a fascinating insight into coral behaviour but the behaviour is not enough to protect it from other threats such as human-caused climate change, overfishing and water pollution.

Ms Deaker says the period when young crown of thorns starfish shift from a vegetarian diet to eating coral, which is an animal, is a critical one. This is because young crown of thorns starfish who survive have the potential to contribute to population outbreaks that could devastate tropical reefs and coral.

Previous research led by Ms Deaker and Professor Byrne has shown juvenile starfish can survive on algae for more than six years when they were previously thought to change diets at four months old, lying in wait until there is an abundance of coral.

CAPTION

A small juvenile crown of thorns starfish (approx. 15mm) retreating after being stung by coral.

CREDIT

Dione Deaker

=Caught on tape=

Marine biologists have reported seeing injured juvenile starfish and have suggested that it may be been caused by predators.

"However, seeing it caused by coral came as a complete surprise," said Ms Deaker.

"This shows that the coral use stinging cells as protection to strike back in an attempt to give itself a fighting chance against attacking coral predators."

In the study, Ms Deaker and Professor Byrne, along with colleagues at the national Marine Science Centre, Coffs Harbour, monitored the condition, growth and survival of 37 juvenile crown of thorns in isolation away from potential predators and reared them on a diet of coral prey for over 3 months.

They found coral stings caused injuries that severely reduced the arm length of the starfish by up to 83 percent.

37.8 percent of juveniles were damaged by coral and four juveniles (10.8 percent) with severe injuries did not recover and died.

The sting attacks from the coral also delayed the growth of juveniles, extending the time they need to maintain a vegetarian diet.

The young starfish had a reflex response to being stung when they encountered coral. Their arms recoiled and twisted when their tube feet came into contact with the coral polyps.

"Sometimes the juveniles never recovered and died, but in most cases injured juveniles recovered and can regenerate their arms in about 4 months," said Ms Deaker.

"Despite being prey of crown of thorns starfish, coral can potentially influence the survival of juveniles and the appearance of a population outbreak on a reef by delaying their transition into an adult that can reproduce."

Armed with these observations, the study shows that coral are a risky food choice for young crown of thorns starfish.

Although coral injury was able to slow down the growth of the juvenile starfish, their ability to regenerate shows the resilience of this reef predator as a highly prolific species.

Professor Byrne said: "The importance of this study in showing the disconnect between size and age of the juveniles reinforces how challenging it is to understand the dynamics of adult population replenishment."

CAPTION

A juvenile corn of thorns starfish with ultimately fatal damage to the arms and central disk.

CREDIT

Dione Deaker

Long-term monitoring shows successful restoration of mining-polluted streams

Despite differences in aquatic life and toxic metals in streams across a broad region of the western United States, scientists found common responses to cleanup of acid mine drainage

UNIVERSITY OF CALIFORNIA - SANTA CRUZ

Research News

 

IMAGE: LEVIATHAN CREEK BELOW AN ABANDONED OPEN PIT MINE, AN EPA SUPERFUND SITE IN THE SIERRA NEVADA, WHERE IRON OXIDE DEPOSITS COAT THE STREAM BOTTOM. view more 

CREDIT: DAVID HERBST

Many miles of streams and rivers in the United States and elsewhere are polluted by toxic metals in acidic runoff draining from abandoned mining sites, and major investments have been made to clean up acid mine drainage at some sites. A new study based on long-term monitoring data from four sites in the western United States shows that cleanup efforts can allow affected streams to recover to near natural conditions within 10 to 15 years after the start of abatement work.

The four mining-impacted watersheds--located in mountain mining regions of California, Colorado, Idaho, and Montana--were all designated as Superfund sites under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), which helps fund the cleanup of toxic-waste sites in the United States. They are among the few acid mine drainage sites where scientists have conducted extended studies to monitor the effectiveness of the remediation efforts.

"The good news from them all is that Superfund investments can restore the water quality and ecological health of the streams," said David Herbst, a research scientist at UC Santa Cruz and coauthor of a paper on the new findings to be published in the June issue of Freshwater Science. The paper is currently available online.

For the past two decades, Herbst has been monitoring streams affected by acid mine drainage from the Leviathan mine in the central Sierra Nevada. The new study developed out of discussions he had with other scientists involved in long-term studies of similar sites.

"There are not many of these long-term studies of impacted watersheds, and by combining our data we could identify the common threads of recovery between these different sites," Herbst said.

To assess the recovery of aquatic life in streams and rivers severely polluted by the abandoned mines, the researchers combined data from long-term monitoring over periods of 20 years or more. They used aquatic insects and other diverse invertebrate life (such as flatworms and snails) as indicators of the restoration of ecological health, with nearby unpolluted streams serving as standards for comparison.

Even with differing mixes of toxic metals and different treatment practices used to control the pollution at each site, the studies documented successful recovery to near natural conditions within 10 to 15 years. Much of the recovery was rapid, occurring within the first few years of treatment.

"These promising results and shared paths suggest that even daunting environmental problems can be remedied given the effort and investment," Herbst said.

The research also revealed that the sites shared common responses despite differences in the species of aquatic life occurring across this broad geographic region. Shared feeding habits, patterns of development, and behavioral characteristics unified how stream invertebrates responded to the alleviation of metal pollutants.

Species with traits such as feeding on algae, long life cycles, and clinging to the surfaces of stones became increasingly common as toxicity declined over time. Species that were more prevalent when metal concentrations were higher had traits such as rapid development, short life cycles, feeding on deposits of organic matter, and an ability to escape quickly off the bottom by drifting into the flow of water.

The species most sensitive to toxic metals are the mayflies, stoneflies, and caddisflies. Across all streams, the loss of these sensitive insects occurred at a toxicity level predicted by lab bioassays based on the combined levels of the toxic metals present.

"The convergence of these responses across streams and at a level consistent with how water quality criteria are established lends support to guidelines established for what chemical conditions are protective of stream and river ecosystems," Herbst said.

The additive toxicity of the metals present determined the response to pollutants, he noted, showing that water quality standards should be based on combined metals present rather than singly for each metal. In other words, even if a metal is below its toxic level, when it is present with other metals the combined effect may exceed the tolerance of aquatic life.

"It is vital to account for this factor in how water quality standards for metals are applied," Herbst said.

CAPTION

A few kilometers downstream from the mine, significant recovery of water quality and aquatic life has occurred since remediation of acid mine drainage.

CREDIT

David Herbst

The other coauthors of the study are William Clements at Colorado State University in Fort Collins, Michelle Hornberger and Terry Short at the U.S. Geological Survey in California, and Christopher Mebane at the USGS in Idaho.

On the front line: The impact of suicide on health professionals and first responders

UNIVERSITY OF OTAGO

Research 

 

IMAGE: PHD STUDENT SUICIDE AND MENTAL HEALTH RESEARCH GROUP DEPARTMENT OF PSYCHOLOGICAL MEDICINE UNIVERSITY OF OTAGO, WELLINGTON NEW ZEALAND view more 

CREDIT: LUKE PILKINTON-CHING UNIVERSITY OF OTAGO

More research is urgently needed into the impact that attending suicide events is having on paramedics and other first responders, a researcher at the University of Otago, New Zealand, says.

PhD student Renan Lyra, a psychologist by training, says a significant proportion of police officers, firefighters and paramedics will attend at least one suicide event in their careers, but there has been little research into the impact this has on their personal and professional lives and on their own suicide risk.

Mr Lyra has reviewed 25 research papers on the impact attending a suicide event has on those on the front line in countries including the US, the UK, Australia and in Europe.

His review, which has just been published in the international journal PLOS ONE, is understood to be the first to specifically look at the impact of work-related exposure to suicide among first responders and mental health professionals.

He found almost all the research papers published over the last 10 years were focused on the impact the suicide of a patient had on the psychologists, psychiatrists, social workers and nurses who worked with them, rather than on first responders.

Mr Lyra says attending the scene of a suspected suicide is one of the most critical and traumatic situations first responders are likely to encounter in the course of their work.

"For first responders, the emotional impact includes the high emotional labour they need to expend to manage their feelings, something which has been found to be associated with increased thoughts of suicide among firefighters."

Research which detailed the impact of attending a suicide event on mental health professionals found they experienced sadness, shock, feelings of blame, hopelessness, guilt, self-doubt, grief and anger.

"Their professional reactions ranged from sadness at work and increased awareness of suicide risk to reduced professional confidence and fear of publicity and litigation. They were also more likely to refer patients on to psychiatrists."

Only two of the 25 research papers Mr Lyra examined measured mental health outcomes in mental health professionals after a patient's suicide, with burnout and PTSD reported as significant adverse outcomes.

Mr Lyra says exposure to suicide is a major risk factor for suicide, with mental health professionals and first responders themselves being at higher risk of suicide than the general population.

"One of the explanations for the higher rates of suicides among these professions is their higher levels of occupational-related psychological distress, and for first responders, work-related Post Traumatic Stress Disorder (PTSD). One of the contributors to this may be their higher exposure to suicide."

Mr Lyra says suicide is a major global health and social issue, with an estimated 800,000 people dying by suicide each year.

"The social and psychological costs of suicide are high. For every suicide, it has been estimated that between six and 20 people, usually family members and friends of those who died, are adversely affected psychologically and emotionally. This group is likely to include those who encounter suicide while on duty."

###

The research paper, 'Occupational exposure to suicide: A review of research on the experiences of mental health professionals and first responders' is published in the international journal, PLOS ONE and can be read here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0251038

Study finds limited access to paid video streaming services contributes to piracy growth

Researchers examined the impact of Netflix expansion on demand for pirated

content.

INSTITUTE FOR OPERATIONS RESEARCH AND THE MANAGEMENT SCIENCES

Research News

 

CATONSVILLE, MD, May 4, 2021 - Paid video streaming services on your television, smart phone or other devices are increasingly replacing traditional video entertainment platforms of cable, satellite and broadcast TV. The growth of these services, known in the industry as over-the-top (OTT) media services, may be accompanied by a rise in pirated content, particularly where access to those services may be restricted, a group of researchers has found.

The researchers studied the effects of the Netflix - one of the leading global companies in paid video streaming - and its growth in 40 Asian countries. They also studied one country where access to Netflix was restricted, which is where they found that the search for pirated content increased.

The research study to be published in the May issue of the INFORMS journal Marketing Science, "The Effect of Over-the-Top Media Services on Piracy Search: Evidence from a Natural Experiment," is authored by Shijie Lu of the University of Houston, Koushyar Rajavi of the Georgia Institute of Technology and Isaac Dinner of Indeed in Austin, Texas.

When Netflix announced its global market expansion plans in January 2016, the primary telecommunications firm in Indonesia decided to block the service from consumers in that country. At the same time, Netflix was able to expand as planned in 40 other Asian countries.

"When we took a closer look at the impact of these decisions on the consumer marketplace, we found that Netflix's failure to launch in Indonesia led to a 19.7% increase in search for pirated movies and TV shows they could have received legally if they had access to Netflix," said Lu. "This percentage increase is relative to the other countries where consumers had legal access to Netflix content."

The researchers investigated the effect on piracy demand by collecting monthly search data from Google for a sample of 304 Netflix titles, including both movies and TV programs, in 41 Asian countries, between October 2014 and June 2016. This period represents the time before the Netflix expansion and the months immediately following that announcement.

"In our research, we recognized that while limited access to paid streaming services is an obvious driver in the demand for pirated content, it is still only one factor in why consumers search for pirated content," said Rajavi. "Consumers may search for pirated content in locations where they do have paid access to OTT services, but they simply want to avoid paying market rates."

"Still, by studying the data, we were able to determine that search for pirated content is more closely associated with restricted access to the content, as opposed to consumers simply trying to avoid paying market rates for content they could buy through legal channels," added Dinner.

Another key finding of the research was that demand for pirated content is also higher for less dialogue-oriented content, which is consistent with the greater appeal of dialogue-light content to non-English-speaking consumers.

###

About INFORMS and Marketing Science

Marketing Science is a premier peer-reviewed scholarly marketing journal focused on research using quantitative approaches to study all aspects of the interface between consumers and firms. It is published by INFORMS, the leading international association for operations research and analytics professionals. More information is available at http://www.informs.org or @informs.

Disclaimer: AAAS and EurekA

Mysterious hydrogen-free supernova sheds light on stars' violent death throes

ROYAL ASTRONOMICAL SOCIETY

Research News

 

IMAGE: ARTIST'S IMPRESSION OF A YELLOW SUPERGIANT IN A CLOSE BINARY WITH A BLUE, MAIN SEQUENCE COMPANION STAR, SIMILAR TO THE PROPERTIES DERIVED FOR THE 2019YVR PROGENITOR SYSTEM IN KILPATRICK ET... view more 

CREDIT: KAVLI IPMU / AYA TSUBOI

A curiously yellow pre-supernova star has caused astrophysicists to re-evaluate what's possible at the deaths of our Universe's most massive stars. The team describe the peculiar star and its resulting supernova in a new study published today in Monthly Notices of the Royal Astronomical Society.

At the end of their lives, cool, yellow stars are typically shrouded in hydrogen, which conceals the star's hot, blue interior. But this yellow star, located 35 million light years from Earth in the Virgo galaxy cluster, was mysteriously lacking this crucial hydrogen layer at the time of its explosion.

"We haven't seen this scenario before," said Charles Kilpatrick, postdoctoral fellow at Northwestern University's Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), who led the study. "If a star explodes without hydrogen, it should be extremely blue -- really, really hot. It's almost impossible for a star to be this cool without having hydrogen in its outer layer. We looked at every single stellar model that could explain a star like this, and every single model requires that the star had hydrogen, which, from its supernova, we know it did not. It stretches what's physically possible."

Kilpatrick is also a member of the Young Supernova Experiment, which uses the Pan-STARRS telescope at Haleakalā, Hawaii to catch supernovae right after they explode. After the Young Supernova Experiment spotted supernova 2019yvr in the relatively nearby spiral galaxy NGC 4666, the team used deep space images captured by NASA's Hubble Space Telescope, which fortunately already observed this section of the sky two and a half years before the star exploded.

"What massive stars do right before they explode is a big unsolved mystery," Kilpatrick said. "It's rare to see this kind of star right before it explodes into a supernova."

The Hubble images show the source of the supernova, a massive star imaged just a couple of years before the explosion. Several months after the explosion however, Kilpatrick and his team discovered that the material ejected in the star's final explosion seemed to collide with a large mass of hydrogen. This led the team to hypothesize that the progenitor star might have expelled the hydrogen within a few years before its death.

"Astronomers have suspected that stars undergo violent eruptions or death throes in the years before we see supernovae," Kilpatrick said. "This star's discovery provides some of the most direct evidence ever found that stars experience catastrophic eruptions, which cause them to lose mass before an explosion. If the star was having these eruptions, then it likely expelled its hydrogen several decades before it exploded."

In the new study, Kilpatrick's team also presents another possibility: a less massive companion star might have stripped away hydrogen from the supernova's progenitor star. However, the team will not be able to search for the companion star until after the supernova's brightness fades, which could take up to a decade.

"Unlike its normal behaviour right after it exploded, the hydrogen interaction revealed it's kind of this oddball supernova," Kilpatrick said. "But it's exceptional that we were able to find its progenitor star in Hubble data. In four or five years, I think we will be able to learn more about what happened."

Destruction and Renewal: Nova by Samuel R. Delany | Tor.com

https://www.tor.com › 2018/03/29 › destruction-and-re...

Mar. 29, 2018 — Novas have long captured the imagination of those who watch the sky. The very idea of a star becoming unstable and exploding into cosmic fury ...

Overloading the senses: Samuel Delany's Nova | Tor.com

https://www.tor.com › 2010/11/04 › overloading-the-se...

Nov. 4, 2010 — The theme of Nova is sensory stimulus. There's Dan, who had his senses burned out observing a nova, so now he sees and hears and smells ...

'Oddball supernova' appears strangely cool before exploding

Never-before-seen scenario 'stretches what's physically possible'

NORTHWESTERN UNIVERSITY

Research News

 

IMAGE: HUBBLE SPACE TELESCOPE (HST) IMAGING SHOWING THE EXPLOSION SITE OF 2019YVR FROM 2.5 YEARS BEFORE ITS EXPLOSION. UPPER LEFT: THE SUPERNOVA ITSELF IS SEEN IN AN IMAGE FROM THE GEMINI-SOUTH... view more 

CREDIT: CHARLES KILPATRICK / NORTHWESTERN UNIVERSITY

A curiously yellow star has caused astrophysicists to reevaluate what's possible within our universe.

Led by Northwestern University, the international team used NASA's Hubble Space Telescope to examine the massive star two-and-a-half years before it exploded into a supernova. At the end of their lives, cool, yellow stars are typically shrouded in hydrogen, which conceals the star's hot, blue interior. But this yellow star, located 35 million lightyears from Earth in the Virgo galaxy cluster, was mysteriously lacking this crucial hydrogen layer at the time of its explosion.

"We haven't seen this scenario before," said Northwestern's Charles Kilpatrick, who led the study. "If a star explodes without hydrogen, it should be extremely blue -- really, really hot. It's almost impossible for a star to be this cool without having hydrogen in its outer layer. We looked at every single stellar model that could explain a star like this, and every single model requires that the star had hydrogen, which, from its supernova, we know it did not. It stretches what's physically possible."

The team describes the peculiar star and its resulting supernova in a new study, which was published today (May 5) in the Monthly Notices of the Royal Astronomical Society. In the paper, the researchers hypothesize that, in the years preceding its death, the star might have shed its hydrogen layer or lost it to a nearby companion star.

Kilpatrick is a postdoctoral fellow at Northwestern's Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and member of the Young Supernova Experiment, which uses the Pan-STARSS telescope at Haleakalā, Hawaii, to catch supernovae right after they explode.

Catching a star before it explodes

After the Young Supernova Experiment spotted supernova 2019yvr in the relatively nearby spiral galaxy NGC 4666, the team used deep space images captured by NASA's Hubble Space Telescope, which fortunately already observed this section of the sky.

"What massive stars do right before they explode is a big unsolved mystery," Kilpatrick said. "It's rare to see this kind of star right before it explodes into a supernova."

The Hubble images showed the source of the supernova, a massive star imaged just a couple years before the explosion. Although the supernova itself appeared completely normal, its source -- or progenitor star -- was anything but.

"When it exploded, it seemed like a very normal hydrogen-free supernova," Kilpatrick said. "There was nothing outstanding about this. But the progenitor star didn't match what we know about this type of supernova."

Direct evidence of violent death

Several months after the explosion, however, Kilpatrick and his team discovered a clue. As ejecta from the star's final explosion traveled through its environment, it collided with a large mass of hydrogen. This led the team to hypothesize that the progenitor star might have expelled the hydrogen within a few years before its death.

"Astronomers have suspected that stars undergo violent eruptions or death throes in the years before we see supernovae," Kilpatrick said. "This star's discovery provides some of the most direct evidence ever found that stars experience catastrophic eruptions, which cause them to lose mass before an explosion. If the star was having these eruptions, then it likely expelled its hydrogen several decades before it exploded."

In the new study, Kilpatrick's team also presents another possibility: A less massive companion star might have stripped away hydrogen from the supernova's progenitor star. The team, however, will not be able to search for the companion star until after the supernova's brightness fades, which could take up to 10 years.

"Unlike it's normal behavior right after it exploded, the hydrogen interaction revealed it's kind of this oddball supernova," Kilpatrick said. "But it's exceptional that we were able to find its progenitor star in Hubble data. In four or five years, I think we will be able to learn more about what happened."

###

The study, "A cool and inflated progenitor candidate for the type Ib supernova 2019 yvr at 2.6 years before explosion," was supported by NASA (award numbers GO-15691 and AR-16136), the National Science Foundation (award numbers AST-1909796, AST-1944985), the Canadian Institute for Advanced Research, the VILLUM Foundation and the Australian Research Council Centre of Excellence. In addition to the Hubble Space Telescope, the researchers used instruments at the Gemini Observatory, Keck Observatory, Las Cumbres Observatory, Spitzer Space Telescope and the Swope Telescope.

 MEN'S STUDIES

Coalitions and conflict among men

In the Bolivian Tsimané, who supports who is affected by physical size, social status, and existing cooperative and antagonistic relationships

MAX PLANCK INSTITUTE FOR EVOLUTIONARY ANTHROPOLOGY

Research News

 

IMAGE: ILLUSTRATION OF MALE MEMBERS OF THE BOLIVIAN TSIMANÉ. IN THEIR STUDY, THE RESEARCHERS DESCRIBE WHICH CONFLICTS MAY ARISE BETWEEN MEN IN THIS SMALL-SCALE SOCIETY AND WHO SUPPORTS WHO IN CASE... view more 

CREDIT: DANIEL REDHEAD

Daniel Redhead, from the Max Planck Institute for Evolutionary Anthropology, and Chris von Rueden, from the University of Richmond, published a new study that describes coalition formation among men in Tsimané Amerindians living in Amazonian Bolivia, over a period of eight years. In two Tsimané communities, the authors describe the inter-personal conflicts that tend to arise between men, and the individual attributes and existing relationships that predict the coalitional support men receive in the event of conflicts.

Conflicts that arise between men concern disputes over access to forest for slash-and-burn horticulture, as well as accusations of theft, laziness, negligence, domestic abuse, and sexual affairs.

Men tend to reciprocate coalitional support

Key findings are that men who are kin or who exchange food and labor are more likely to subsequently provide support to each other in the event of a conflict. Men tend to reciprocate coalitional support over time, and an ally of a man's current ally is likely to become a future ally. The authors also find evidence that men who share a common adversary become allies, though this finding did not hold consistently across the eight years of the study.

In reference to the impact of these findings, Redhead, said: "Coalition formation among men is multiply determined in the Tsimané, and likely in other human societies. Importantly, the social network analyses we used show that properties of the network, not just the individual, affect coalition formation."

Higher status men more likely to provide coalitional support

Furthermore, Tsimané men who are physically formidable or who have more informal influence in their community are more likely to provide coalitional support to others. Evidence was mixed that they receive more coalitional support. These higher status men are hubs of their community's coalitional support network, and there is little indication that this network is partitioned into clearly separable coalitions that divide the community.

"In the Tsimané, men who have higher informal status strategically deploy coalitional support to build up a diverse, community-wide following. In many cases, both disputants in a conflict will report the same higher status man as having provided coalitional support, which points to the often blurry line between coalitional support and conflict mediation", von Rueden said. "Politics is the art of persuading enough people you have their interests at heart. In less egalitarian societies where there is more privately available wealth and community sizes are larger, status is less contingent on providing direct support to a broad swath of community members, there is greater homophily by status, and coalitional divides within a community are more likely to be pronounced."

Redhead and von Rueden focus their study on men because they at present lack longitudinal data on women's coalition formation. However, there is reason to analyze coalition networks separately by gender, given evidence of gender differences in how men and women build and leverage their social relationships, particularly in societies like the Tsimané where there is a pronounced gendered division of labor.

###

Original publication:

Daniel Redhead and Christopher R. von Rueden
Coalitions and conflict: A longitudinal analysis of men's politics
Evolutionary Human Sciences, 05 May 2021, https://doi.org/10.1017/ehs.2021.26

 

Examination of an Estonian patient helped discover a new form of muscular dystrophy

ESTONIAN RESEARCH COUNCIL

Research News

 

IMAGE: PROFESSOR OF CLINICAL GENETICS OF THE UNIVERSITY OF TARTU KATRIN ÕUNAP view more 

CREDIT: UNIVERSITY OF TARTU

In about a quarter of patients with hereditary diseases, the cause of the disease remains unclear even after extensive genetic testing. One reason is that we still do not know enough about the function of many genes. Of the 30,000 known genes, just a little more than 4,000 have been found to be associated with hereditary diseases.

At the Department of Clinical Genetics of the University of Tartu Institute of Clinical Medicine, under the leadership of Professor Katrin Õunap, patients with hereditary diseases of unclear cause have been studied in various research projects since 2016. In collaboration with the Broad Institute of MIT and Harvard, these patients have undergone extensive genome-wide sequencing analyses at the level of the exome (the sequence of all genes), genome (whole DNA sequence), and transcriptome (RNA transcribed from the genome).

Professor Katrin Õunap described that in a girl with progressive muscle weakness, they found two changes in the JAG2 gene that had not been associated with any hereditary disease before. "In cooperation with an international team of researchers, we found 22 other patients with similar problems and changes in the JAG2 gene from all over the world," said Õunap.

The study showed that the misfunction of the JAG2 gene interferes with the development of muscle cells and their ability to recover, thereby causing progressive muscle damage.

Estonian researchers conducted a transcriptome (RNA) analysis of the patient's muscle tissue, which provided important information on pathological changes in gene expression in muscle cells. "Also, for the first time in Estonia, our patient underwent a special muscular magnetic resonance imaging scan, which revealed a pattern of muscle involvement characteristic of pathogenic variants in JAG2 in lower limb muscles," explained Õunap.

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The article was published in the American Journal of Human Genetics in cooperation with researchers from Estonia, Belgium, the United States, the United Kingdom, France, Germany, Poland, Iran, Egypt and Japan.