How thousands of nature’s longest sperm squeeze into a tiny fruit fly

By bringing mathematics and biology together, researchers at the Simons Foundation’s Flatiron Institute have uncovered the dynamics of how supersize fruit fly sperm behave when packed into a small space.

Simons Foundation

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Visual explainer that shows the enormous length of the fruit fly sperm compared to the sperm storage sac: The sac is only one tenth the length of the fruit fly sperm. The fruit fly sperm is 40 times longer than a human sperm.

view more 

Credit: Lucy Reading-Ikkanda/Simons Foundation

The supersize sperm of fruit flies swim about their storage cavity with elegant churning choreography, and scientists at the Simons Foundation’s Flatiron Institute have figured out why.

Within the abdomen of the humble fruit fly (Drosophila melanogaster) are some of the longest sperm the animal kingdom has ever known. Uncoiled, the tails of these swimmers stretch around 2,000 microns long. That’s nearly the length of the male fly itself, and 10 times longer than the storage organ that houses sperm by the thousands.

Yet surprisingly, the sperm-filled organ isn’t a chaotic mess. The sperm form orderly flows, undulating like waves. “Each one of them is dragging this massive cargo, and they’re not getting entangled,” says Jasmin Imran Alsous of the Flatiron Institute’s Center for Computational Biology (CCB). “That’s what really blew my mind.” The question became: How could they move around in such tight quarters without getting tangled up in knots?

To find out, Imran Alsous and her collaborators developed mathematical models that could be used to simulate the highly complex biological system. They found that, rather than propelling themselves by creating waves through fluid like human sperm, fruit fly sperm actually push off their brethren to propel themselves forward. When thousands of sperm interact in this manner, the result is a collective churn.

The researchers report this new understanding of how individual fly sperm movements give rise to orderly collective dynamics in a new paper published June 22 in Nature Physics.

The larger ethos behind their work — building collaborations to develop quantitative approaches to reproductive biology — could help scientists answer other fundamental questions in biology, such as how nutrients flow through networks of veins, how organelles self-assemble within cells and how embryos develop.

“This is how you’re going to reach a truly quantitative understanding of biology,” says CCB Director Mike Shelley.

For the full story behind the new work, read our article “Mysteries of Fruit Fly Sperm Untangled by Mathematical Models.”

About the Flatiron Institute (CCB)

The Flatiron Institute is the research division of the Simons Foundation. The institute's mission is to advance scientific research through computational methods, including data analysis, modeling and simulation. The institute's Center for Computational Biology develops new and innovative methods of examining data in the biological sciences whose scale and complexity have historically resisted analysis. The center's mission is to develop modeling tools and theory for understanding biological processes and to create computational frameworks that will enable the analysis of the large, complex data sets being generated by new experimental technologies.

Stylized illustration of sperm tails coiled up and aligned tidily.

Credit

Lucy Reading-Ikkanda/Simons Foundation

Sperm Time Lapse [VIDEO] 

Time-lapse of a collection of fruit fly sperm, with red-colored heads and gray-colored tails, showing how they "flow" together, showing the collective dynamics that Jasmin Imran Alsous and colleagues are studying.

Single Sperm Time Lapse [VIDEO] 

Colorized time-lapse of an individual sperm. The sperm uncoils at random like an earthworm in a puddle showing the juxtaposition of single sperm dynamics vs. the collective.

Credit

J Imran Alsous, et al./Flatiron Institute

---

Journal

Nature Physics

DOI

10.1038/s41567-026-03305-4 

Method of Research

Experimental study

Subject of Research

Cells

Article Title

The physical consequences of sperm gigantism

Article Publication Date

22-Jun-2026

 

Study finds social determinants of health can match or exceed genetic risk in predicting common diseases

Life circumstances add important insight beyond genetics alone

The Mount Sinai Hospital / Mount Sinai School of Medicine

LinkedInWeChatBlueskyMessageWhatsAppEmail

New York, NY — [June 22, 2026] — A new study from the Icahn School of Medicine at Mount Sinai shows that social determinants of health—including environmental conditions, health behaviors, access to resources, and social well-being—can play an equally important or even greater role than genetics in predicting a person’s risk of developing common diseases.

Published in the June 22 online issue of The American Journal of Human Genetics [DOI: 10.1016/j.ajhg.2026.05.014], the study, titled "Integrating Social Determinants of Health and Genetic Risk in Disease Risk Models," examined how inherited genetic risk and social, behavioral, and environmental factors interact to influence disease risk across diverse populations.

Using data from the All of Us Research Program—a nationwide National Institutes of Health (NIH) initiative—researchers analyzed genetic information, electronic health records, and survey responses from participants across the United States. They evaluated six common conditions: asthma, chronic kidney disease, coronary heart disease, high cholesterol, breast cancer, and prostate cancer.

The researchers found that incorporating social determinants of health significantly improved disease risk prediction beyond genetics alone. For four of the six diseases studied, social, behavioral, and environmental factors contributed as much as, or more than, commonly used genetic risk scores.

"Genes are an important part of the equation, but they do not determine destiny," says senior corresponding author Samira Asgari, PhD, Assistant Professor of Genetics and Genomic Sciences at the Icahn School of Medicine at Mount Sinai. "We found that the circumstances of people's lives—their environments, behaviors, and social experiences—can contribute as much as genetics to predicting disease risk. To truly understand health, we have to look at the whole person, not just their DNA."

The findings highlight the complex factors that shape health and disease. While advances in genetics have expanded researchers' ability to estimate inherited risk, the new findings suggest that combining genetic information with social and environmental context may provide a more complete understanding of disease risk and help inform future prevention strategies.

To conduct the study, researchers analyzed more than 100 survey-based and community-level measures related to social and environmental conditions. Rather than focusing on a handful of predefined risk factors, the team developed a framework that identifies broader patterns across many aspects of people's lives and evaluates how those patterns contribute to disease risk.

Among the notable findings, the researchers observed associations between disease risk and factors that are less frequently examined in genetic and biological research, including loneliness. While the study was not designed to determine cause and effect, the findings highlight areas that warrant further investigation.

"Some risk factors, such as smoking, have been studied extensively for decades,” says first author Abhijith Biji, a PhD student in the Asgari lab who led the work. "What is especially intriguing is that we also observed associations involving factors like loneliness. Understanding how these experiences may become biologically embedded could open new avenues for research and ultimately improve our understanding of disease."

The authors emphasize that the study does not identify simple causes of disease and should not be interpreted as showing that any single factor directly leads to illness. Also, because many of the survey responses were collected at a single point in time, the research cannot determine whether a particular factor preceded the onset of disease.

Instead, the researchers say, the study provides a framework for integrating genetic and non-genetic information to build more comprehensive disease risk models.

The researchers believe this approach could strengthen population health research, improve disease prevention strategies, enhance risk assessment, and support future efforts to develop more personalized approaches to health care. Future studies will explore how social determinants of health can be integrated with additional biological measures and investigate the biological mechanisms that may connect social experiences to disease.

"Our goal is to build a more complete understanding of health and disease," says Dr. Asgari. "By combining genetics with social and environmental context, we can move toward risk models that better reflect the realities of people's lives and help advance more personalized approaches to health."

The authors, as listed in the journal, are Abhijith Biji, Kathleen Ferar, Vikas Pejaver, Eimear E. Kenny, Bian Liu, and Samira Asgari.

This work was supported in part by NIH grants: R21MD019104 and R35GM160530 and the Clinical and Translational Science Awards (CTSA) grant UL1TR004419 from the National Center for Advancing Translational Sciences. Research reported in the publication was also supported by the Office of Research Infrastructure of the National Institutes of Health under award numbers S10OD026880 and S10OD030463.

-####-

About the Icahn School of Medicine at Mount Sinai

The Icahn School of Medicine at Mount Sinai is internationally renowned for its outstanding research, educational, and clinical care programs. It is the sole academic partner for the seven member hospitals* of the Mount Sinai Health System, one of the largest academic health systems in the United States, providing care to New York City’s large and diverse patient population. 

The Icahn School of Medicine at Mount Sinai offers highly competitive MD, PhD, MD-PhD, and master’s degree programs, with enrollment of more than 1,200 students. It has the largest graduate medical education program in the country, with more than 2,700 clinical residents and fellows training throughout the Health System. The Graduate School of Biomedical Sciences offers 13 degree-granting programs, conducts innovative basic and translational research, and trains more than 470 postdoctoral research fellows.

Ranked 11th nationwide in National Institutes of Health (NIH) funding, the Icahn School of Medicine at Mount Sinai is among the 90th percentile of U.S. private medical schools in Sponsored Programs Direct Expenditures per Principal Investigator, according to the Association of American Medical Colleges.  More than 6,900 scientists, educators, and clinicians work within and across dozens of academic departments and multidisciplinary institutes with an emphasis on translational research and therapeutics. Through Mount Sinai Innovation Partners (MSIP), the Health System facilitates the real-world application and commercialization of medical breakthroughs made at Mount Sinai.

-------------------------------------------------------

* Mount Sinai Health System member hospitals: The Mount Sinai Hospital; Mount Sinai Brooklyn; Mount Sinai Morningside; Mount Sinai Queens; Mount Sinai South Nassau; Mount Sinai West; and New York Eye and Ear Infirmary of Mount Sinai.  

---

Journal

The American Journal of Human Genetics

DOI

10.1016/j.ajhg.2026.05.014 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Integrating Social Determinants of Health and Genetic Risk in Disease Risk Models

Article Publication Date

22-Jun-2026

Protective human antibodies target West Nile and related viruses

Istituto di Ricerca in Biomedicina

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Molecular reconstruction of WNV and mechanism of binding by virus neutralizing antibodies reported in the study

view more 

Credit: Christopher Barnes and Zaira Contejean, Stanford University

West Nile virus (WNV) is transmitted by mosquitoes and is increasingly relevant for Europe and worldwide. It can cause severe brain infection and death, yet there is no specific antiviral treatment or approved human vaccine. A collaborative study published in Immunity analyzed blood from WNV convalescents in Serbia to understand antibody immune responses and identify protective human monoclonal antibodies with potential to prevent or treat WNV and related orthoflavivirus infections.

Davide Robbiani's Laboratory at the Institute for Research in Biomedicine (IRB, affiliated with Università della Svizzera italiana) in Bellinzona, Switzerland, together with international collaborators, identified monoclonal antibodies that may help address this unmet medical need.

Among them, antibody W010 recognizes a distinct site on the virus envelope domain III, a key surface protein involved in viral attachment and infection. W010 protected mice when administered before and even 5 days after exposure to WNV. A second antibody, W014, showed broader cross-neutralization against pathogenic orthoflaviviruses, including Japanese encephalitis, Murray Valley encephalitis, Saint Louis encephalitis and Usutu viruses.

The findings define vulnerable sites on WNV that could inform vaccine development, and highlight antibody candidates with prophylactic and therapeutic potential. They may also guide interventions for a wider group of encephalitic orthoflavivirus infections.

---

Journal

Immunity

DOI

10.1016/j.immuni.2026.05.013 

Article Title

Analysis of West Nile disease convalescents identifies human monoclonal antibodies protective against West Nile and related orthoflaviviruses

Article Publication Date

22-Jun-2026

Habits help animals survive

University of Exeter

Facebook

XLinkedInWeChatBluesky
Email

The ability to form and break habits helps animals survive and find food efficiently – and may have benefitted our hunter-gatherer ancestors – according to new research.  

Forming habits can make complex tasks “automatic”, reducing the mental effort required. 

But breaking habits may also be essential if a habit is no longer beneficial.  

The research team – from universities of Exeter, Bristol, Humboldt (Berlin) and Stockholm – created simulations to test the evolutionary pros and cons of forming and breaking habits. 

They find that habits could help an animal forage for food while keeping attention free to look out for predators – suggesting evolutionary benefits for creatures of habit.  

“Lots of psychological research has examined habits in humans – but we don’t often ask the same questions about animals,” said Professor Olof Leimar, from Stockholm University. 

“Our aim is to change this, by investigating a possible evolutionary explanation for habits, namely that habits enhance an individual’s ability to multitask in a realistic ecological context for many animals.” 

The team created simulations where virtual animals had various food choices, which they could learn about to exploit efficiently, and had to watch for predators. 

Foraging habits could be formed, freeing up attention for evading predators, but sometimes the food environment changed – meaning new habits were required.  

“We show that forming and breaking foraging habits can substantially reduce the chance of being killed by a predator, without drastically reducing foraging success,” said Dr Sasha Dall, from the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.   

“This is effective as long as environmental conditions remain stable enough between changes. 

“We argue that the ability to form and break habits is a type of behavioural flexibility that is likely to be favoured evolutionarily in a range of ecological conditions.” 

Dr Dall added: “From morning coffee routines to familiar routes home, habits are often seen as mindless behaviours. But our study suggests habits may have evolved for a very good reason: they help animals stay alive. 

“This type of learning is likely to have helped our ancestors – but things have changed very radically in our world, so the way that habits form and break may not be well-tuned to the current pace of life that humans experience.” 

Dr Dall was supported by a Royal Society Leverhulme Trust Senior Fellowship for part of this work. 

The paper, published in the journal Evolution Letters, is entitled: “Evolution of behavioral flexibility and the forming and breaking of habits.” 

---

Journal

Evolution Letters

DOI

10.1093/evlett/qrag024 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Evolution of behavioral flexibility and the forming and breaking of habits

Article Publication Date

19-Jun-2026

 

New technique filters PFAS forever chemicals using “molecular Velcro”

University of Florida

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

A new gel-based material developed by University of Florida chemical engineers filters  PFAS “forever chemicals” from water more efficiently than many widely used commercial options.

The advance offers a potential new path to filtering out PFAS, which has been linked to health effects including birth defects and some cancers. Importantly, the new material doesn’t itself use fluorine to trap PFAS, helping to reduce fluorinated chemicals in the filtration supply chain.

“One of the big challenges is that these chemicals are present at such low concentrations, so they’re very difficult to detect and separate, but they can still impact human health,” said Joshua Moon, Ph.D., a professor of chemical engineering at UF who led the new study. “It’s like putting a drop of food coloring in an Olympic-sized swimming pool and then trying to get all the food coloring back out. It’s not easy.”

Moon and his doctoral student Lakshay Dhamania published their findings June 8 in the journal Energy and Environmental Materials. Moon’s lab is now working to further test and refine their PFAS-filtering methods for potential application in commercial and municipal water filtration.

In what Moon describes as “molecular Velcro,” the new material uses electrical charges designed to trap PFOA, one of the most abundant versions of PFAS in the environment. The gel allows PFOA molecules to bind throughout the material rather than only on its surface, improving its filtration capacity.

The gel can then be used multiple times by flushing out the PFOA with common solvents.

One of the researchers’ goals was to identify a way to filter out PFAS without relying on fluorinated materials. If those materials break down, they can potentially release fluorinated compounds back into the environment.

“A lot of the materials out there either don’t work well or have to rely on using fluorinated stuff to bind PFAS. We were able to develop these gel-type adsorbents that work well without having PFAS-like substances in the material itself,” Moon said.

For Moon, the long-term goal extends beyond a single filtration material.

By building polymers whose chemistry can be adjusted piece by piece, the researchers hope to uncover broader rules for trapping PFAS. That includes compounds that are harder to remove from water than PFOA.

“Maybe we can create new design principles or a better understanding of existing materials to overcome some of the big challenges that commercial treatment processes can't really do,” Moon said.

---

Journal

Energy & Environmental Materials

DOI

10.1002/eem2.70435 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Chemically Modular, Nonfluorinated Polymer Adsorbents for Capturing Per- and Polyfluoroalkyl Substances (PFAS)

Article Publication Date

8-Jun-2026