Thursday, February 22, 2024

 

A third of trans masculine individuals on testosterone ovulate


Study from Amsterdam UMC's Center of Expertise on Gender Dysphoria shows that one-third of trans masculine individuals taking testosterone ovulate

Peer-Reviewed Publication

AMSTERDAM UNIVERSITY MEDICAL CENTER





"Trans masculine people are people born female but do not identify as such, for example they feel male, gender fluid or non-binary. Our examination of their ovarian tissue shows that 33% of them show signs of recent ovulation, despite being on testosterone and no longer menstruating," says Joyce Asseler, PhD candidate at Amsterdam UMC.  

Trans masculine people often use hormone treatment with testosterone to masculinize physically. This hormone usually stops them from menstruating. In that case, it is often assumed that ovulation does not take place. 

Physician-researcher Joyce Asseler and gynecologist Norah van Mello examined the ovarian tissue of transgender people who had their ovaries removed as part of their gender-affirming treatment. They had all used testosterone for at least 1 year prior to and at the time of the procedure. Their analysis shows that 17 of the 52 study participants (33%) show signs of recent ovulation in the ovarian tissue.  

"Testosterone apparently has a heterogenous effect on ovarian tissue. We don't know why one person ovulates and another person doesn't. In any case, we cannot explain this difference by the type of testosterone, or how long someone has been taking testosterone," says Asseler.  

People who ovulate can, in theory, also get pregnant. This also applies to these trans people. For them, it is therefore necessary to use contraceptives if they are sexually active with someone who produces sperm cells. "The physical and mental consequences of an unplanned and unwanted pregnancy are enormous. It is important that trans masculine people and their healthcare providers are aware of this risk and act accordingly. Furthermore, this discovery can contribute to better care for trans masculine people who experience abdominal cramping," concludes Asseler. 

 

Disclaimer: AAAS 

 

Climate change linked to rise in mental distress among teens, according to Drexel study


Peer-Reviewed Publication

DREXEL UNIVERSITY




Worsening human-induced climate change may have effects beyond the widely reported rising sea levels, higher temperatures, and impacts on food supply and migration – and may also extend to influencing mental distress among high schoolers in the United States.

According to a representative survey of 38,616 high school students from 22 public school districts in 14 U.S. states, the quarter of those adolescents who had experienced the highest number of days in a climate disaster within the past two years and the past five years – such as hurricanes, floods, tornadoes, droughts, and wildfire – had 20% higher odds of developing mental distress than their peers who experienced few or no disaster events.

The paper is the first large scale research looking at mental health of adolescents following multiple disaster events -- including the timing, frequency, and duration of the events – spanning 83 federally declared climate disasters occurring within 10 years before the survey was completed. The findings, using May 2019 data on sadness/hopelessness and short sleep from the U.S. Youth Risk Behavior Survey and disaster data from the Federal Emergency Management Agency, were published this month in the journal Preventive Medicine Reports.

“We know that climate change has and will have catastrophic impacts across the globe,” said lead author Amy Auchincloss, PhD, an associate professor of epidemiology in the Dornsife School of Public Health. “But we were alarmed to find that climate related disasters already were affecting so many teens in the U.S. For example, within the past 2 years, many school districts in our study were subject to climate disasters for over 20 days.”

Respondents reported mental health distress by responding affirmatively to persistent feelings of sadness or hopelessness and short sleep duration, two factors that previous studies strongly link to mental health disorders among adolescents. The group controlled for other factors that may influence mental health, such as age, race, gender, experience of bullying, concerns about school safety and household income.

A positive, but not statistically significant, link between experiencing climate disasters and mental distress was also found when spanning ten years before the U.S. Youth Risk Survey.

“We found the strongest effects on mental distress in the 2 years immediately following a climate disaster – with the effect gradually weakening 5 to 10 years after the disaster,” said co-author Josiah Kephart, PhD, an assistant professor in the Dornsife School of Public Health.

As the results cannot prove causation, the authors say they would like to see more studies into the range of effects of climate change on youth and methods to improve preparing for potential worsening mental health among this population.

Already, roughly half of adolescents have experienced a mental health disorder in their childhood or teen years, according to the U.S. Department of Health and Human Services.

“Resources for the youth mental health crisis already have difficulty meeting demand and demand will increase as disasters increase,” said co-author Esther Chernak, MD, a clinical professor and director of the Center for Public Health Readiness and Communication at Dornsife School of Public Health. “The current study is evidence that clinicians, policymakers, parents, and many others with a stake in youth mental health can point to when advocating for increasing adolescent-specific mental health resources – particularly in lower-income communities who will be hit hardest by disasters.”

Drexel’s Dornsife School of Public Health is home to significant ongoing work addressing health and climate change. Among other projects, the school’s Urban Health Collaborative recently received National Institutes of Health funding to support establishment of the Drexel Climate Change and Urban Health Research Center (CCUH), which with foster research on the effects of climate change on health across the Americas. The Urban Health in Latin America  Project (SALURBAL-Climate), of which Dornsife School of Public Health is an institutional partner, funds research on climate change’s links to health and health inequity impacts across Latin America using data on as any as 400 cities in 11 countries. Additional work at the school, in collaboration with the World Resources Institute (WRI), WRI Brasil, SALURBAL, and WRI Mexico, seeks to deepen our understanding of the relationship between neighborhood-scale heat mortality and neighborhood social characteristics in two Brazilian cities; the findings of which aim to inform public policy.

In addition to Auchincloss, additional authors on the study includes Dominic A. Ruggiero, and Meghan T. Donnelly, who were graduate students at Drexel at the time of this work.

 

Combination of group competition and repeated interactions promotes cooperation


Peer-Reviewed Publication

UNIVERSITY OF ZURICH




One of the great unresolved mysteries of human evolution is how pro-social, cooperative behavior could have evolved. What led to the establishment of a behavior that prioritizes the benefit of the community over that of the individual in a world where materially successful individuals reproduce, and others slowly perish?

The prevailing theory suggests that this occurred due to repeated interactions. Over generations, humans learned that cooperative behavior pays off in the long run. People collaborate because they anticipate interacting with the same individuals in the future. Therefore, those who behave antisocially suffer reputational damage and are punished by others with uncooperative behavior, manifesting that uncooperative behavior does not pay off in the long run.

Exchange experiment in Papua New Guinea

However, there is strong empirical evidence that people behave cooperatively even in non-recurrent and anonymous interactions where there is no risk of reputational damage. How can this be explained? Behavioral economists from the Universities of Zurich, Lausanne and Konstanz addressed this question by conducting an experiment among indigenous people in Papua New Guinea.

In a setup resembling a trust game, pairs of individuals had to exchange money with each other and to decide whether they wanted to act selfishly and uncooperatively or rather socially and cooperatively (see box). The conclusion: when paired with an anonymous member of their own community, participants exchanged very large amounts. In pairings with members of other communities, however, very little was transferred.

Prevailing paradigm challenged

In a comprehensive theoretical analysis linked with the experiment, the researchers show that the prevailing theory of repeated interactions alone cannot explain the evolution of human cooperation, since repeated interactions only enable the evolution of cooperation if the individual ability to reduce cooperation is arbitrarily restricted. Without such arbitrary restrictions, cooperation collapses.

This is because even in repeated interactions, there is an incentive to gain an advantage by always cooperating a little less than the partner. Over time, this leads to a breakdown in cooperation. "This is perhaps the most provocative result of our study, as it completely contradicts the mainstream,” says corresponding author Ernst Fehr of the University of Zurich.

Cooperating groups compete with each other

A second common thesis on how cooperation could evolve also falls short: the idea that groups with several team-oriented members fare better in competition – and that general cooperation spreads because less cooperative groups die out. However, the theoretical analysis shows that the migration of cooperative and non-cooperative individuals between groups weakens the cooperative groups. Furthermore, there is also competition between cooperative groups, which weakens overall cooperation in the population.

Combined, “super-additive” approach is key

So how can the obvious fact be explained that people often behave very cooperatively even in one-time interactions? The authors show that this can be explained by the simultaneous interaction of both mechanisms. They found that the two well-known mechanisms, “repeated interactions” and “group competition,” synergistically interact and lead to a form of super-additive cooperation.

First author Charles Efferson of the University of Lausanne summarizes the study’s results as follows: “Repeated interactions create an incentive for cooperation within the group. However, this is a fragile state. Group competition, on the other hand, has a stabilizing effect on this fragile state. This strengthens intra-group cooperation on the one hand and promotes uncooperative behavior with outsiders on the other.” Thus, social motives seem to have developed in human history under the combined influence of both mechanisms.

 

Literature:

Charles Efferson, Helen Bernhard, Urs Fischbacher, and Ernst Fehr (2024): Super-additive cooperation. Nature. DOI: 10.1038/s41586-024-07077-w

 

((Box))

Experiment in Papua New Guinea

The participants were each given five monetary units in local currency, equivalent to half a day's wages. They were then divided into pairs and a one-time interaction between the people took place, an anonymous sequential exchange. Person 1 was asked to decide how much of the five monetary units they wanted give to person 2, knowing that the amount would be doubled and given to person 2. This decision was announced to person 2. Person 2 could now decide how much of their five monetary units they would like to give to person 1. This amount was also doubled. This lead to a situation in which the reciprocal transfer of monetary units (= co-operation) is advantageous for both parties. However, if person 2 acted selfishly and transferred nothing to person 1, and if person 1 expected this and also acted selfishly, they would also transfer nothing to person 2.

 

UC Irvine study shows similarities and differences in human and insect vision formation


Discovery offers insights into retinal disease origins and potential therapeutic targets

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - IRVINE




Irvine, Calif., Feb. 22, 2024  Researchers at the University of California, Irvine have discovered profound similarities and surprising differences between humans and insects in the production of the critical light-absorbing molecule of the retina, 11-cis-retinal, also known as the “visual chromophore.” The findings deepen understanding of how mutations in the RPE65 enzyme cause retinal diseases, especially Leber congenital amaurosis, a devastating childhood blinding disease.

 

For the study, recently published online in the journal Nature Chemical Biology, the team used X-ray crystallography to study NinaB, a protein found in insects that functions similarly to the RPE65 protein found in humans. Both are crucial for synthesis of 11-cis-retinal, and their absence results in severe visual impairment.

 

“Our study challenges traditional assumptions about the similarities and differences of human and insect vision,” said corresponding author Philip Kiser, UCI associate professor of physiology & biophysics as well as ophthalmology. “While these enzymes share a common evolutionary origin and three-dimensional architecture, we found that the process by which they produce 11-cis-retinal is distinct.”

 

Creation of 11-cis-retinal begins with the consumption of foods like carrots or pumpkins containing compounds used for vitamin A generation, such as beta-carotene. These nutrients are metabolized by carotenoid cleavage enzymes, including NinaB and RPE65. It was previously known that humans require two of these enzymes to produce 11-cis-retinal from beta-carotene, whereas insects can achieve the conversion with just NinaB. Gaining insight into how NinaB can couple the two steps into a single reaction along with the functional relationships between NinaB and RPE65 was a key motivation for the study.

 

“We found that structurally, these enzymes are very much alike, but the locations in which they perform their activity are different,” said lead author Yasmeen Solano, a graduate student in Kiser’s laboratory at the UCI Center for Translational Vision Research. “Understanding key features within the NinaB structure has led to an enhanced understanding of the catalytic machinery necessary to support the function of the retinal visual pigments. Through our study of NinaB, we were able to learn about the structure of a key portion of RPE65 that had not previously been resolved. This discovery is vital in understanding and addressing loss-of-function mutations in RPE65.”

 

Other team members included Michael Everett, a junior specialist in the Kiser lab, and Kelly Dang and Jude Abueg, biological sciences undergraduates at the time.

 

This work was supported by the National Science Foundation under grant CHE-2107713, the Department of Veterans Affairs under grant BX004939 and the National Institutes of Health under grant EY034519-01S1.

 

About the University of California, Irvine: Founded in 1965, UCI is a member of the prestigious Association of American Universities and is ranked among the nation’s top 10 public universities by U.S. News & World Report. The campus has produced five Nobel laureates and is known for its academic achievement, premier research, innovation and anteater mascot. Led by Chancellor Howard Gillman, UCI has more than 36,000 students and offers 224 degree programs. It’s located in one of the world’s safest and most economically vibrant communities and is Orange County’s second-largest employer, contributing $7 billion annually to the local economy and $8 billion statewide. For more on UCI, visit www.uci.edu.

 

Media access: Radio programs/stations may, for a fee, use an on-campus ISDN line to interview UCI faculty and experts, subject to availability and university approval. For more UCI news, visit news.uci.edu. Additional resources for journalists may be found at https://news.uci.edu/media-resources.

 

Compound vital for all life likely played a role in life’s origin


A chemical compound essential to all living things has been synthesised in a lab in conditions that could have occurred on early Earth, suggesting it played a role at the outset of life, finds a new study led by UCL researchers.

Peer-Reviewed Publication

UNIVERSITY COLLEGE LONDON




The compound, pantetheine, is the active fragment of Coenzyme A. It is important for metabolism - the chemical processes that maintain life. Earlier studies failed to synthesise pantetheine effectively, leading to suggestions that it was absent at life’s origin.

In the new study, published in the journal Science, the research team created the compound in water at room temperature using molecules formed from hydrogen cyanide, which was likely abundant on early Earth.

Once formed, the researchers said, it is simple to envisage how pantetheine might have aided chemical reactions that led from simple forerunners of protein and RNA molecules to the first living organisms – a moment that is thought to have occurred 4 billion years ago.

The study challenges the view among some researchers in the field that water is too destructive for life to originate in it and that life more likely originated in pools that periodically dried out.

Driving the reactions that produced pantetheine were energy-rich molecules called aminonitriles, which are closely chemically related to amino acids, the building blocks of proteins and of life.

Members of the same team, led by Professor Matthew Powner (UCL Chemistry), have already used similar chemistry powered by aminonitriles to demonstrate how other key biological ingredients could be created at the origin of life, including peptides (protein-creating chains of amino acids) and nucleotides (the building blocks of RNA and DNA).

Professor Powner, senior author of the paper, said: “This new study is further evidence that the basic structures of biology, the primary molecules that biology is built from, are predisposed to form through nitrile chemistry.

“The ease with which different classes of biological molecules can be made using nitriles has convinced me that, rather than life being preceded by one molecule such as RNA, and there being an ‘RNA world’ before life began, the basic molecules of biology emerged alongside each other – a network of RNAs, proteins, enzymes and cofactors leading to the first living organisms.

“Our future work will look at how these molecules came together, how pantetheine chemistry talks to RNA, peptide and lipid chemistry for instance, to deliver chemistry that the individual classes of molecule could not deliver in isolation.”

A notable earlier attempt to synthesise pantetheine was made in 1995 by the late American chemist Stanley Miller, who had started the field of origin of life experiments three decades earlier, creating amino acids from four simple chemicals in glass tubes.

However, in the later 1995 experiment, the yields of pantetheine were very low and required extremely high concentrations of chemicals that had been dried out and sealed in an airtight tube before they were heated to 100 degrees Centigrade.

Dr Jasper Fairchild (UCL Chemistry), a lead author of the study, who conducted the work as part of his PhD, said: “The major difference between Miller’s study and ours is whereas Miller tried to use acid chemistry, we used nitriles. It’s the nitriles that bring the energy and the selectivity. Our reactions just run in water and produce high yields of pantetheine with relatively low concentrations of chemicals needed.”

Professor Powner added: “It had been assumed you should make these molecules from acids, because using acids appears to be biological, and that is what we are taught at school and at university. We are taught peptides are made from amino acids.

“Our work suggests this conventional view has ignored an essential ingredient, the energy required to forge new bonds. The reactions look a little different with nitriles but the end products – the basic units of biology – are indistinguishable whether formed through acid or nitrile chemistry.”

While the paper focuses solely on the chemistry, the research team said that the reactions they demonstrated could plausibly have taken place in pools or lakes of water on the early Earth (but not likely in the oceans as the concentrations of the chemicals would likely be too diluted).

The new study was supported by the Engineering and Physical Sciences Research Council, the Simons Foundation and the Volkswagen Foundation. As a result of his work on the origins of life, Professor Powner was named a finalist in the 2021 Blavatnik Awards for Young Scientists. The awards are for scientists aged 42 or younger whose research “is already transforming technology and our understanding of the world”.

Compound vital for all life likely played a role in life’s origin

A chemical compound essential to all living things has been synthesised in a lab in conditions that could have occurred on early Earth, suggesting it played a role at the outset of life, finds a new study led by UCL researchers.

The compound, pantetheine, is the active fragment of Coenzyme A. It is important for metabolism - the chemical processes that maintain life. Earlier studies failed to synthesise pantetheine effectively, leading to suggestions that it was absent at life’s origin.

In the new study, published in the journal Science, the research team created the compound in water at room temperature using molecules formed from hydrogen cyanide, which was likely abundant on early Earth.

Once formed, the researchers said, it is simple to envisage how pantetheine might have aided chemical reactions that led from simple forerunners of protein and RNA molecules to the first living organisms – a moment that is thought to have occurred 4 billion years ago.

The study challenges the view among some researchers in the field that water is too destructive for life to originate in it and that life more likely originated in pools that periodically dried out.

Driving the reactions that produced pantetheine were energy-rich molecules called aminonitriles, which are closely chemically related to amino acids, the building blocks of proteins and of life.

Members of the same team, led by Professor Matthew Powner (UCL Chemistry), have already used similar chemistry powered by aminonitriles to demonstrate how other key biological ingredients could be created at the origin of life, including peptides (protein-creating chains of amino acids) and nucleotides (the building blocks of RNA and DNA).

Professor Powner, senior author of the paper, said: “This new study is further evidence that the basic structures of biology, the primary molecules that biology is built from, are predisposed to form through nitrile chemistry.

“The ease with which different classes of biological molecules can be made using nitriles has convinced me that, rather than life being preceded by one molecule such as RNA, and there being an ‘RNA world’ before life began, the basic molecules of biology emerged alongside each other – a network of RNAs, proteins, enzymes and cofactors leading to the first living organisms.

“Our future work will look at how these molecules came together, how pantetheine chemistry talks to RNA, peptide and lipid chemistry for instance, to deliver chemistry that the individual classes of molecule could not deliver in isolation.”

A notable earlier attempt to synthesise pantetheine was made in 1995 by the late American chemist Stanley Miller, who had started the field of origin of life experiments three decades earlier, creating amino acids from four simple chemicals in glass tubes.

However, in the later 1995 experiment, the yields of pantetheine were very low and required extremely high concentrations of chemicals that had been dried out and sealed in an airtight tube before they were heated to 100 degrees Centigrade.

Dr Jasper Fairchild (UCL Chemistry), a lead author of the study, who conducted the work as part of his PhD, said: “The major difference between Miller’s study and ours is whereas Miller tried to use acid chemistry, we used nitriles. It’s the nitriles that bring the energy and the selectivity. Our reactions just run in water and produce high yields of pantetheine with relatively low concentrations of chemicals needed.”

Professor Powner added: “It had been assumed you should make these molecules from acids, because using acids appears to be biological, and that is what we are taught at school and at university. We are taught peptides are made from amino acids.

“Our work suggests this conventional view has ignored an essential ingredient, the energy required to forge new bonds. The reactions look a little different with nitriles but the end products – the basic units of biology – are indistinguishable whether formed through acid or nitrile chemistry.”

While the paper focuses solely on the chemistry, the research team said that the reactions they demonstrated could plausibly have taken place in pools or lakes of water on the early Earth (but not likely in the oceans as the concentrations of the chemicals would likely be too diluted).

The new study was supported by the Engineering and Physical Sciences Research Council, the Simons Foundation and the Volkswagen Foundation. As a result of his work on the origins of life, Professor Powner was named a finalist in the 2021 Blavatnik Awards for Young Scientists. The awards are for scientists aged 42 or younger whose research “is already transforming technology and our understanding of the world”.

 

Protein integral to sperm development and male fertility identified


A little-known protein helps safeguard genomic stability while chromosomes are cut and spliced back together


Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - DAVIS

Protein Integral to Sperm Development and Male Fertility Identified 

IMAGE: 

RESEARCHERS AT THE UC DAVIS COLLEGE OF BIOLOGICAL SCIENCES HAVE DISCOVERED THAT A LITTLE-KNOWN PROTEIN CALLED ATF7IP2 HELPS TO INACTIVATE THE X AND Y CHROMOSOMES DURING CELL DIVISIONS THAT LEAD TO SPERM CELLS. THIS IS A CRUCIAL STEP FOR MAINTAINING GENOME STABILITY. SHOWN HERE ARE MOUSE CHROMOSOMES (GREEN), WITH ATF7IP2 PROTEIN (RED) ACCUMULATING ON A CONDENSED PART OF THE X CHROMOSOME.

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CREDIT: KRIS ALAVATTAM




Early in the development of sperm, a strange event happens: the X and Y chromosomes condense into tight packages and are sequestered away from the other 44 human chromosomes. If any part of this process goes awry, the cells cannot mature into sperm. Researchers in the UC Davis College of Biological Sciences have now identified an important link in this process — a little-known protein called ATF7IP2.

“This could be a critical factor for ensuring male fertility,” said Satoshi Namekawa, professor of microbiology and molecular genetics, whose team contributed to the new findings. Their results, published Feb. 21 in Genes & Development, could help elucidate the causes of male infertility.

A dangerous moment for DNA

The discovery sheds light on a pivotal moment in the production of sperm that is necessary for the health of our species — but also potentially dangerous.

The cells that give rise to sperm contain 46 chromosomes — two copies each of chromosomes 1 through 22, plus one of each sex chromosome, X and Y. The sperm will eventually carry only half a set — 23 chromosomes, including either X or Y. Before they are divided up, the 22 sets of homologous chromosomes pair up, and segments of DNA are swapped between each pair. This recombination shuffles the genetic deck, ensuring that the next generation of humans will have diverse genes that determine disease resistance and many other traits.

But recombination carries risks.The DNA must be cut and rejoined dozens of times without a single error. If the wrong chromosomes are paired up, the wrong cuts are made, or the wrong ends are rejoined, the resulting embryo may fail to develop, or the offspring may end up missing genes, or with extra copies, triggering genetic diseases.

Namekawa and his team have spent years studying the way that germline cells (which produce sperm and egg cells) prevent this from happening. They and others have found that a constellation of proteins called the DNA damage response (DDR) guides the process. When a person is exposed to radiation, chemicals, or anything else that breaks DNA, the DDR ensures that the resulting loose ends are correctly reattached. DDR plays a similar role in recombination, making sure that chromosomes only pair up with their twins and that cuts are rejoined.

But unlike other pairs of chromosomes, X and Y are actually different from one another. If they swap parts, this could damage the genome, said Kris Alavattam, a former doctoral student in Namekawa’s lab, now at the Fred Hutchinson Cancer Center in Seattle.

“When X and Y are unable to match up, the DDR causes them to come together into their own compartment, away from the other chromosomes,” he said.

This happens when an enzyme called SETDB1 modifies the protein spools that the X and Y chromosomes’ DNA is wrapped around, causing it to coagulate into a dense structure called heterochromatin. The resulting inactivation prevents recombination and silences the X’s and Y’s genes at the correct time to prevent them from interfering with the process of divvying up chromosomes into sperm cells.

A likely suspect

In 2016, Alavattam and Namekawa looked for a molecular link between DDR and the inactivation of the X and Y chromosomes. It could have been any one of hundreds of proteins, but Alavattam and Namekawa noticed that one little-known protein, called ATF7IP2, was abundant in sperm-forming cells undergoing recombination — and was virtually absent from all other tissues. They also knew that the ATF7IP2 protein sometimes attaches to the SETDB1 enzyme.

“It suggested that ATF7IP2 might regulate SETDB1 and recruit it to the X and Y chromosomes,”  Alavattam said.

Alavattam did experiments to answer this question until graduating with his Ph.D. in 2020. A new graduate student, Jasmine Esparza, then joined Namekawa’s lab in 2021 and continued the experiments. Also collaborating were Ryuki Shimada in the laboratory of Kei-ichiro Ishiguro at Kumamoto University, Japan.

In the newly published work, Alavattam, Namekawa and Esparza found that male mice with the ATF7IP2 gene disabled are healthy but infertile, with no sperm. In the cells that would normally become sperm, the SETDB1 enzyme does not modify the X and Y chromosomes, so these two chromosomes aren’t compacted into heterochromatin. Together, these results suggest that ATF7IP2 plays an indispensable role in the development of sperm and is necessary for male fertility.

Esparza and Namekawa, together with project scientist Mengwen Hu, found that ATF7IP2 also plays other roles in sperm development. In addition to targeting X and Y, it causes SETDB1 to silence genetic parasites called retroelements, which are scattered across all of the chromosomes and can cause genomic errors.

They also found that ATF7IP2 plays another, seemingly opposite role: it activates certain genes on the other, non-sex chromosomes, which are important in recombination and sorting of chromosomes into sperm cells.

“It’s very surprising” to see that ATF7IP2 has such diverse functions, Namekawa said.

Studying this protein could reveal some causes of male infertility. Namekawa and Esparza are already looking into new questions, hoping to find out how ATF7IP2 activates some parts of the other 44 chromosomes, even as it inactivates X and Y. For that job, it might link up with proteins other than SETDB1.

“We’ve identified a really important pathway,” said Namekawa. “We intend to follow it to see where it leads.”

Additional authors on the paper include: at UC Davis, Yasuhisa Munakata, Kai Otsuka, Yuka Kitamura and Yu-Han Yeh; at UC Davis and Kumamoto University, Hironori Abe; at Cincinnati Children’s Hospital Medical Center, Anna R. Kohrs; at Kumamoto University, Saori Yoshimura; at Cincinnati Children’s Hospital Medical Center and University of Cincinnati College of Medicine, Yueh-Chiang Hu and Paul R. Andreassen; at University of Tokyo, Jihye Kim.

Preventative healthcare at your fingertips

University of Ottawa researcher develops bilingual healthcare app to help Canadians stay healthy in face of healthcare crisi
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UNIVERSITY OF OTTAWA




VIDEO:

WITH HOSPITAL EMERGENCY DEPARTMENTS OVERWHELMED AND CANADIANS FEELING FRUSTRATED BY A LACK OF PRIMARY CARE ACCESS, A FREE WEBAPP DEVELOPED AT THE UNIVERSITY OF OTTAWA IS PROVIDING TRUSTED INFORMATION ABOUT PREVENTATIVE HEALTH CARE TO EMPOWER THE PUBLIC TO TAKE CONTROL OF THEIR OWN HEALTH  .view more


CREDIT: BONNIE FINDLEY, UNIVERSITY OF OTTAWA



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Textbooks convey essentialist messages about sex and gender, study of widely used U.S. books shows


Reports and Proceedings

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)




After analyzing six of the most widely used high school biology textbooks in the United States, researchers report these texts depart from established scientific knowledge about sex and gender, instead portraying these categories in a manner consistent with “essentialism” – the assumption that categories of living things have underlying “essences.” To date, what high school biology textbooks have taught adolescents about sex and gender has gone unexamined in studies of the influences of essentialism in this space. The essentialist view on sex and gender is informed by several assumptions. Scientific research on sex and gender is inconsistent with these assumptions, yet they are commonly held. Although sex (a biological phenomenon) and gender (a sociocultural phenomenon) are carefully distinguished among biologists who study these phenomena, this distinction is often absent in public discourse, where sex and gender are typically conflated. If biology textbooks also conflate the two phenomena, they would be “lending authority to an uninformed lay view that is out of step with well-established scientific knowledge,” write Brian Donovan et al. in their Policy Forum.

Donovan and colleagues investigated high school biology textbooks as a sociocultural source of essentialist ideas about sex and gender, focusing on books adopted in at least two of the following highly populous states: California, Texas, New York, and Florida. They identified six textbooks published between 2009 and 2016 that they estimate are collectively used by 66% of introductory high school biology classes across the U.S. The authors analyzed select chapters of these textbooks, that discussed both genetics and sex or gender, looking at whether sex and gender were explicitly differentiated in a given paragraph, as one analysis. Of the paragraphs coded in this category, none differentiated between sex and gender, they report, meaning these texts inappropriately conflate between a biological phenomenon (sex) and a sociocultural one (gender). Further analyses show that textbooks underemphasize the vast amount of continuous variability within sex/gender groups, an idea consistent with those who hold essentialist views (who tend to believe that individuals within a sex/gender group are uniform). Altogether, their results led them to suggest that the textbooks studied convey essentialist messages about sex/gender. “Biology education has long been criticized for presenting an oversimplified view of genetic inheritance,” say Donovan and team. “The present results highlight another important way in which biology education falls short… More optimistically, the present results also suggest how textbooks could be changed to avoid these undesirable consequences.” The authors highlight several aspects of current textbooks that could be revised.