The 2011 tsunami triggered interspecific hybridization, yet species boundaries were maintained

Nine years of Genomic Tracking of a Tsunami-Induced Hybrid Population Reveals How Foreign Genomes Are Eliminated

Research Organization of Information and Systems

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Left: A freshwater pond formed in Otsuchi, Iwate Prefecture, by the tsunami and land subsidence associated with the 2011 Great East Japan Earthquake (Photo: Seiichi Mori).
Center: A hybrid population of threespine stickleback and Japan Sea stickleback discovered in this pond (Photo: Takuya Hosoki).
Right: Schematic illustration showing how the marine Japan Sea stickleback was carried into the freshwater pond by the tsunami, while the freshwater threespine stickleback was carried from upstream by the backwash. The two species came into contact, resulting in interspecific hybridization (Illustration: Chihiro Kinoshita).

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Credit: Chihiro Kinoshita、Takuya Hosoki

How are species boundaries maintained in the face of environmental disturbance? This is not only a fundamental question in evolutionary biology but also an increasingly important one as human activities and climate change alter habitats and bring previously separated species into contact.

As mechanisms preventing gene exchange between populations, known as reproductive isolation, accumulate, populations can eventually diverge into separate species. When reproductive isolation is incomplete, however, environmental changes can bring closely related species into contact and lead to hybridization. For species boundaries to persist despite extensive hybridization, much of the genomic regions introduced from another species must be eliminated. Yet how rapidly this process occurs in nature, and which reproductive isolation mechanisms contribute to the removal of foreign genomic regions, have remained poorly understood.

The tsunami triggered by the Great East Japan Earthquake in 2011 dramatically altered habitats along the Pacific coast of northeastern Japan. Otsuchi Town in Iwate Prefecture was struck by a tsunami exceeding 10 meters in height. The tsunami and subsequent backwash are thought to have brought the marine Japan Sea stickleback, Gasterosteus nipponicus, from the sea and a freshwater population of the threespine stickleback, Gasterosteus aculeatus, from upstream into newly formed freshwater habitats in the town center. This brought the two closely related fish species into contact and resulted in interspecific hybridization.

A research team comprising scientists from the National Institute of Genetics (NIG), Hokkaido University, Gifu Kyoritsu University, Kyoto University, Ishinomaki Senshu University, Nagoya University, Keio University, The University of Tokyo, and Tokyo University of Marine Science and Technology tracked this hybrid population for nine years. In 2012, 38% of the individuals sampled were hybrids. Over the following years, however, genomic regions derived from G. nipponicus rapidly declined across the genome, and by 2020 the population had returned to an almost entirely G. aculeatus genomic composition. Because the generation time of this population is approximately one year, most of the G. nipponicus-derived genome was eliminated within about 10 generations.

Genomic regions containing major reproductive isolation loci associated with freshwater adaptation, migration to the sea, mate choice, and hybrid male sterility showed particularly rapid declines in G. nipponicus ancestry. However, these major loci alone could not explain the genome-wide removal observed over 10 generations. Individual-based simulations suggested that numerous weak genetic incompatibilities distributed throughout the genome may also have contributed to the rapid elimination of G. nipponicus ancestry.

“There were two major surprises in this study,” said Takuya Hosoki and Jun Kitano. “First, we did not expect genomic regions associated with major reproductive barriers to be purged so rapidly. Second, we were surprised that most of the foreign genome continued to disappear over subsequent generations. An important next question is whether this combination of a few strong reproductive barriers and many weak genetic incompatibilities represents a general mechanism by which species boundaries are maintained after hybridization.”

This study is one of the few to track genomic changes in a natural population from immediately after interspecific hybridization through approximately 10 generations. By directly observing the progressive removal of foreign genomic regions, the study reveals how multiple reproductive barriers can work together to maintain species boundaries following extensive hybridization.

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About National Institute of Genetics (NIG)
National Institute of Genetics (NIG) was established to carry out broad and comprehensive research in genetics. NIG contributes to the development of academic research as one of the inter-university research institutes constituting the Research Organization of Information and Systems (ROIS).

About the Research Organization of Information and Systems (ROIS)
ROIS is a parent organization of four national institutes (National Institute of Polar Research, National Institute of Informatics, the Institute of Statistical Mathematics and National Institute of Genetics) and the Joint Support-Center for Data Science Research. It is ROIS's mission to promote integrated, cutting-edge research that goes beyond the barriers of these institutions, in addition to facilitating their research activities, as members of inter-university research institutes.

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Journal

Nature Ecology & Evolution

DOI

10.1038/s41559-026-03184-1 

The upper panel shows triangle plots of the genomic composition of individuals collected from 2012 to 2020, with each point representing one individual. In 2012, many hybrids and individuals backcrossed to threespine stickleback were present. Thereafter, genomic regions derived from Japan Sea stickleback rapidly decreased, and after 10 generations, the population had become almost entirely threespine stickleback in genomic composition.

The middle panel schematically illustrates changes in the genomic composition of the hybrid population (Illustration: Chihiro Kinoshita).
The lower panel shows how to read the triangle plot.

Credit

Chihiro Kinoshita

From a baby's smile to a monkey's grin: how emotions shape our behaviour

Universiteit van Amsterdam

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From a baby’s first smile to childhood embarrassment, emotions drive our behaviour and how we relate to the world from the very beginning. A new special issue of Philosophical Transactions of the Royal Society B – edited by UvA psychologists Milica Nikolić and Disa Sauter, along with colleagues Mariska Kret (Leiden University) and Lauri Nummenmaa (University of Turku, Finland) – explores how and why we express our emotions, and how humans and other animals shape their behaviour and social worlds through smiles, glances and body language.

The issue shifts the focus from recognising feelings in others to what occurs within the person expressing the emotion. The guest editorial team adopts a broad perspective: emotional expressions are examined in terms of their origins and development, the commonalities across different animal species, and the roles they play in our behaviour and our lives with others. In this way, emotions are viewed as a visible inner world that acts as a link between brain, body and environment.

Babies initiating shared moments
The special issue comprises a total of 19 articles. Researchers from the UvA provide several key contributions. One study, co-conducted by Cristina Colonnesi, examines how babies in their first year of life shape positive moments with others through smiling. The researchers observed that 8-month-old babies – more so than 4-month-olds – initiate moments of shared positive emotion themselves, for example by smiling and then engaging in mutual laughter with an adult. Rather than primarily reacting to another person's smile, older babies increasingly use their own positive expressions to initiate and sustain warm, enjoyable interactions. This emerging ability may indicate growing flexibility in how babies use their emotions in social contexts.

The body language of shame and guilt
Milica Nikolić demonstrates that self-conscious emotions – such as shame, guilt, shyness or pride - re already visible in a child's facial expressions, body posture and gaze during their first few years of life. These emotions arise when children view themselves through the eyes of others and prove to be more than just an internal feeling.

Various studies show, for instance, that when children feel guilty about something that went wrong, they are subsequently more likely to try to make amends—by helping, sharing, or repairing damage. In contrast, with shame, children are more likely to withdraw, avoid eye contact, or try to steer clear of certain situations. Nikolić and her colleagues emphasise that while the evidence is still limited, these emotions likely play an early role in shaping social behaviour and reputation.

Not every positive emotion comes with a smile
Disa Sauter and her team demonstrate that positive facial emotions are far more than just ‘a smile’. In a study of 22 different positive emotions, based on participants' personal experiences, they examine which facial muscles and movements are activated for each one. They found that certain positive feelings have their own distinct facial profiles that do not involve smiling – such as interest or determination. In the case of determination, the key characteristic is a raised chin.

Other positive emotions, such as amusement or elation, do involve distinct smiles – with upturned corners of the mouth, and often closed eyes and strongly raised cheeks. Through this work, the researchers show that ‘feeling good’ manifests in various facial expressions – even spontaneous ones – and that not every positive emotion comes with a classic smile.

‘Play face’ as social mirror
A fourth study, authored by postdoc Christopher Riddell, Milica Nikolić and colleagues, compares the mimicry of "play faces" – exaggerated, playful expressions resembling smiles, often seen during rough-and-tumble play – across infants, adults and orangutans. Infants and adults are more likely to make a play face themselves when observing one in another person than when the other person has a neutral expression; their own expression mirrors what they see, even in the absence of direct interaction with the person being mirrored. Orangutans rarely exhibit this behaviour. This suggests that, for them, play faces arise primarily during direct social play, whereas in humans, "contagious smiling" can occur outside such play contexts.

Studying emotions where they actually occur
Collectively, the contributions to this special issue demonstrate that emotional expressions play a central role early in development – both in how we behave and in the formation and regulation of social relationships – ranging from a baby’s first smile to the complex body language associated with self-conscious emotions. In their editorial, Nikolić, Kret, Nummenmaa and Sauter call on researchers to study emotions more within real-life contexts, paying attention to how expressions emerge, develop and function for both the individual and those around them.

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Journal

Philosophical Transactions of the Royal Society of London (B )

DOI

10.1098/rstb/381/1959

Article Title

Mechanisms, development, phylogeny and functions of emotional expressions

Article Publication Date

24-Sep-2026

 

Randomized trial finds Transcendental Meditation improves happiness, resilience and self-efficacy in rural Lebanese women

Three months of TM practice significantly reduced perceived stress among women living amid ongoing social, economic and environmental pressures

Maharishi International University

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Three-month changes in resilience, happiness, self-efficacy, and perceived stress among women practicing Transcendental Meditation (TM; blue) and women in the control group (red). Bars show mean change from baseline, including standard errors within parentheses. Compared with the control group, the TM group showed significantly greater improvements in all four measures after three months (p ≤ .001).

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Credit: Maharishi International University

A randomized controlled trial of rural Lebanese women found that three months of Transcendental Meditation practice significantly increased happiness, resilience and self-efficacy while reducing perceived stress, according to research published in the peer-reviewed journal Women's Health. 

The study included 114 women from approximately 20 villages in Lebanon's Chouf region, an area where residents have faced continuing economic instability, political unrest and environmental challenges. Researchers from Maharishi International University in Fairfield, Iowa randomly assigned participants either to learn the Transcendental Meditation technique or to an active control group that received weekly videos on self-development and well-being. 

After three months, the women practicing Transcendental Meditation showed significantly greater improvements than the control group on all four measures assessed by the researchers: happiness, resilience, self-efficacy and perceived stress. The differences between groups were statistically significant at p ≤ .001 for each measure. 

“This is a significant study considering the methods: a randomized controlled trial with 140 subjects, and the findings of statistically significant changes in every measure. This is very encouraging because it shows the women improved across several dimensions of psychological well-being at the same time,” said Marie Loiselle, PhD, principal investigator and researcher in the Department of Maharishi Vedic Science at Maharishi International University. “The results suggest that Transcendental Meditation may offer these women an additional way to cope with the significant pressures they face in daily life.” 

Happiness showed the largest change 

Happiness showed the largest change among the four measures. Women in the Transcendental Meditation group reported increases in happiness at both one and three months. In contrast, the control group showed a small improvement at one month followed by a marked decrease at three months. 

The researchers also found that self-efficacy and perceived stress were significantly related to levels of happiness. In their statistical model, self-efficacy entered as the strongest predictor, followed by perceived stress; together, the two variables accounted for 42% of the variance in happiness. 

Self-efficacy refers to a person's perception of their ability to achieve desired results through their own actions. The researchers found that self-efficacy increased in the Transcendental Meditation group while decreasing in the control group after three months. 

High adherence to the practice 

Participants were encouraged to practice Transcendental Meditation for 20 minutes twice a day. Adherence was high: 60% reported practicing twice a day every day or most days, 18% practiced once a day, and 20% practiced irregularly. No harmful events related to participation were reported. 

The study's randomized controlled design included an active control condition, allowing researchers to compare the effects of learning Transcendental Meditation with participation in another structured activity focused on self-development and well-being. 

“The improvements in self-efficacy and reductions in perceived stress are particularly important because both were related to happiness in our analysis,” said Frederick Travis, PhD, statistician and senior advisor on the study. “These findings provide a basis for further research into approaches that may help people cope with persistent environmental stress.” 

A population facing chronic stress 

The study focused on women in Lebanon's Chouf region. The researchers note that women in Lebanon can face multiple sources of stress, including economic instability, political unrest, environmental problems and gender inequality. Previous research has also identified cultural and social barriers that may discourage some people from seeking professional help for stress and related psychological difficulties. 

The research was conducted in collaboration with the Ladies Foundation for Pure Knowledge, which was nearing the end of a project to teach Transcendental Meditation to approximately 1,000 women in the Chouf region. The organization approached the researchers to investigate whether the practice was producing measurable benefits among the women learning the practice. Susan Hamza, the foundation’s director, reflected on the project, “So many of the participants told me their life had been transformed in many ways that words could not even begin to describe it. We are deeply grateful for all those who were involved in realizing this project.” 

Further research needed 

The researchers emphasize that the findings require confirmation through larger and longer studies. Of the 114 women who enrolled, 83 completed both posttests, and participants were followed for three months. The researchers recommend future studies with six- or 12-month follow-up periods and larger populations in Lebanon and potentially elsewhere in the Middle East. 

The study was approved by the Maharishi International University Research Institute Review Board and registered with the U.S. Clinical Trials Registry (NCT05836129). Funding was provided by the Ladies Foundation of Pure Knowledge in Lebanon and individual donors. The authors reported no potential conflicts of interest. 

About the study 

The study, Improving happiness, resilience, and self-efficacy while reducing stress for rural Lebanese women using the Transcendental Meditation practice: A randomized controlled trial, was authored by Marie Loiselle, PhD, and Frederick Travis, PhD, of Maharishi International University and published in Women's Health in 2026. 

About the Transcendental Meditation Technique

Transcendental Meditation is a simple, natural technique practiced 20 minutes twice each day while sitting comfortably with the eyes closed. It is easily learned, and is not a religion, philosophy, or lifestyle. It does not involve concentration, control of the mind, contemplation, or monitoring of thoughts or breathing. The practice allows the active thinking mind to settle down to a state of inner calm. For more information visit www.tm.org

Some of the Lebanese women from approximately 20 villages in Lebanon's Chouf region, an area where residents have faced continuing economic instability, political unrest and environmental challenges. After three months, the women practicing Transcendental Meditation showed significantly greater improvements than the control group on all four measures assessed by the researchers: happiness, resilience, self-efficacy and perceived stress.

Credit

Ladies Foundation of Pure Knowledge in Lebanon

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DOI

10.1177/17455057261479602

Method of Research

Randomized controlled/clinical trial

Subject of Research

People

Article Title

Improving happiness, resilience, and self-efficacy while reducing stress for rural Lebanese women using the Transcendental Meditation practice: A randomized controlled trial

 

Hue cares? Cornell study says wine color isn't the whole picture

Cornell University\

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Laila Milevski/Cornell University

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Credit: Laila Milevski/Cornell University

ITHACA, N.Y. – When a glass of red wine arrives at the table, most drinkers make a snap judgment before taking a sip. Is the color deep enough? Does the hue suggest quality, or raise a red flag? 

For years, that visual scrutiny has posed a challenge to an emerging category of wine grapes. Interspecific hybrid varieties – cultivars bred by crossing multiple Vitis vinifera species to withstand disease, cold and the mounting pressures of climate change – have been viewed with skepticism by winemakers and sommeliers who worried that the wines they produce simply don't look the part.

New research from Cornell University suggests those concerns may be overblown. The research, published in the American Journal of Enology and Viticulture, found that consumers showed no consistent bias against the color of wines made from hybrid grape varieties. When evaluated alongside pinot noirs from Burgundy, Oregon and the Finger Lakes, several hybrid wines ranked among the most visually appealing in the study – and color, regardless of variety, turned out to be a weak predictor of whether drinkers actually enjoyed what was in the glass. 

“This has been something bugging me for a long time,” said Anna Katharine Mansfield, associate professor of enology at Cornell AgriTech. “Prior to coming to Cornell I worked with breeders at the University of Minnesota and often there was this idea that consumers would reject a wine if its color didn’t look very Vitis vinifera-like. But no one had ever studied that question.” 

Additionally, the research was motivated by chemistry, according to co-author and food science doctoral student Catherine Dadmun.  

“Especially in Europe, there are historic restrictions on the chemical color compounds that appear uniquely in hybrid grapes,” Dadmun said. “This has led to the assumption that these compounds must result in low-quality color. We were trying to clarify what is and isn’t important for consumer perception of color quality from a chemical composition standpoint.”

As winemaking regions across North America and Europe grapple with more erratic weather, late frosts and increasing fungal disease pressure, hybrid cultivars offer a compelling alternative to the European grapes that have dominated fine wine for centuries. Varieties like marquette, Maréchal Foch and St. Croix can be grown with far fewer pesticide applications and survive winters that would devastate conventional vineyards. But commercial adoption has been slowed by persistent doubts about whether consumers will accept the resulting wines. 

 

To test one of those doubts directly, the research team recruited 82 regular red wine drinkers through the Cornell Sensory Evaluation Center and asked them to evaluate eight commercial red wines, five made from hybrid cultivars sourced from New York, Wisconsin, Tennessee and Iowa, plus pinot noirs from three regions, without knowing which was which. Panelists rated how much they liked each wine's appearance, how much they expected to enjoy it based on color alone, and then, after tasting, how much they actually liked it.

The results cut in two directions at once. Color did matter, but mostly as a prelude. Wines that appeared lighter or showed more yellow and brown tones scored lower for visual appeal and generated weaker expectations. Three wines clustered at the bottom of the visual rankings: a Finger Lakes pinot noir, Norton from Tennessee and corot noir from near Albany, New York. But when panelists tasted all eight wines, color’s predictive power largely evaporated. The statistical relationship between appearance liking and actual liking explained only about 8% of the variation in drinkers’ responses. 

“The fact is, taste and aroma are so much more important than color in overall quality perception,” Dadmun said. “When we evaluated hue-liking and overall appearance-liking, the pinot noirs and hybrid grapes were largely in the same pool.” 

The finding holds an implicit challenge to wine industry assumptions. Darker wines have long been associated with higher quality, a bias that has made some winemakers reluctant to promote hybrids. But the Cornell data showed no meaningful correlation between color intensity and actual liking. What seemed to drive the lower visual scores for the three least-liked wines wasn’t lightness per se, but a tendency toward brownish, yellow-tinged hues rather than the deep red-purple that consumers associate with a young, well-made red.

“Another thing to bear in mind with color evaluation is you’re frequently doing this in the glass, not the bottle,” Mansfield said. “You’re rarely buying wine in a clear glass bottle because green glass is more protective, so color is a non-issue in some ways. My hope is that people breeding hybrids can just worry less.” 

For additional information, see this Cornell Chronicle story.

Cornell University has dedicated television and audio studios available for media interviews.

 

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Journal

American Journal of Enology and Viticulture

DOI

10.5344/ajev.2026.25042

Method of Research

Observational study

Subject of Research

People

Article Title

Quality Perception of Interspecific Hybrid Red Wine in Relation to Anthocyanin Profile and Color Parameters

Article Publication Date

23-Sep-2026

 

On ancient Madagascar, large native herbivores paid the price as introduced livestock spread

New analyses of ancient cattle, sheep and goat bones suggest that the rapid spread of introduced livestock 1,200 years ago coincided with forest loss and population declines among large native herbivores.

Columbia Climate School

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New analyses of ancient cattle, sheep and goat bones on Madagascar suggest that the rapid spread of introduced livestock on the island 1,200 years ago coincided with forest loss and population declines among large native herbivores.

A research team led by Oregon State University and the Columbia Climate School published their results in the journal Proceedings of the Royal Society B.

Madagascar provides a unique window into extinct ecosystems and the role humans play in biodiversity loss, said the study’s co-lead author Sean Hixon, a postdoctoral researcher at the Oregon State University College of Science. As many as 90% of Madagascar’s species are found nowhere else. Roughly the size of Oregon and California combined, the island nation has been home to plants and animals that evolved largely in isolation for about 88 million years.

The findings, coupled with evidence that humans may have arrived on Madagascar thousands of years before introduced livestock became widespread, suggest that hunting alone did not drive the extinction of giant lemurs and other megafauna. Instead, the study points to a more complex period of ecological change involving introduced animals, vegetation shifts, climate variability and changing human land use.

“Madagascar’s past shows how tightly linked livelihoods, climate, vegetation and biodiversity can be,” said study co-lead author Leanne Phelps, an associate research scientist working in the Olo Be Taloha Lab based at the Lamont-Doherty Earth Observatory, which is part of the Columbia Climate School.

Over the past five years, the researchers brought together the largest collection to date of ancient introduced livestock bone samples from across Madagascar for radiocarbon and stable isotope analysis.

“The data confirm that livestock rapidly spread across the island about 1,200 years ago, approximately coinciding with the disappearance of animals like elephant birds and pygmy hippos,” said Hixon.

Sedimentary pollen-based vegetation reconstructions indicate grasses likely became more abundant across much of Madagascar within the last millennium. These reconstructions involve analyzing fossil and sub-fossil pollen grains preserved in sediments to infer past plant communities at regional scales and beyond.

Meanwhile, paleoclimate reconstructions suggest that Madagascar experienced uneven patterns of drying during recent millennia, complicating earlier ideas that climate change alone was a key driver of past large animal extinctions.

Over the past 1,000 years, Madagascar’s cattle likely came to rely more heavily on C4 grasses—grasses whose photosynthesis process is well suited to warm and dry weather—as opposed to C3 grasses, which thrive in cooler, wetter conditions.

“Although cattle might have preferred wet habitat, they successfully exploited relatively dry habitat during their earlier spread across the island,” Hixon said.

He added that the earliest documented presence of sheep and cattle in the island’s interior more than a millennium ago likely reflects a rapid spread of livestock across Madagascar. The study findings reinforce the pattern that, despite regional climate changes that unfolded at different times across the island, endemic large herbivores disappeared around the time livestock and predators such as dogs were introduced. This suggests a link between livestock proliferation and past extinctions.

The comparatively late arrival of livestock and the megafauna extinctions, coupled with the early human arrival estimate, suggests that it wasn’t just hunting by humans that drove the extinctions.

“The next step is to understand more about the causal relationships between these associated human and environmental changes, how their relationships varied across Madagascar’s diverse landscapes, and the practical relevance of that for supporting healthy livelihoods and biodiversity today,” Phelps said.

Because livestock on Madagascar remain an important component of many livelihoods, Phelps added, the historical context highlights the immediate importance of efforts to both boost suitable forage in existing open habitat and prevent degradation in remaining biodiverse ecosystems.

“This livestock database can contribute to improving understanding of complex interactions among livestock, people, biodiversity and diverse environmental factors on Madagascar,” she said. “This is essential not only for understanding environmental change in the past, but also for informing land stewardship today and in the future.”

Max Planck Society and the National Science Foundation supported this research. The study featured an international collaboration of scientists from 19 institutions, including Princeton University, Rice University, the University of Michigan, Pennsylvania State University and the University of Tennessee.

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Journal

Proceedings of the Royal Society B Biological Sciences

DOI

10.1098/rspb.2026.0668

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

On Ancient Madagascar, Large Native Herbivores Paid the Price as Introduced Livestock Spread

Article Publication Date

25-Sep-2026