New Model for Human Evolution Suggests Homo Sapiens Arose from Multiple Closely Related Populations

View of the village of Kuboes, on the border of South Africa and Namibia. DNA samples were collected from Nama individuals who have historically lived in the region.
Photo Credit: Brenna Henn/UC Davis

In testing the genetic material of current populations in Africa and comparing against existing fossil evidence of early Homo sapiens populations there, researchers have uncovered a new model of human evolution — overturning previous beliefs that a single African population gave rise to all humans. The new research was published today, May 17, in the journal Nature.

Although it is widely understood that Homo sapiens originated in Africa, uncertainty surrounds how branches of human evolution diverged and how people migrated across the continent, said Brenna Henn, professor of anthropology and the Genome Center at UC Davis, corresponding author of the research.

“This uncertainty is due to limited fossil and ancient genomic data, and to the fact that the fossil record does not always align with expectations from models built using modern DNA,” she said. “This new research changes the origin of species.”

Research co-led by Henn and Simon Gravel of McGill University tested a range of competing models of evolution and migration across Africa proposed in the paleoanthropological and genetics literature, incorporating population genome data from southern, eastern and western Africa.

Are Earth and Venus the only volcanic planets? Not anymore.

LP 791-18 d is an Earth-size world about 90 light-years away. The gravitational tug from a more massive planet in the system, shown as a blue disk in the background, may result in internal heating and volcanic eruptions – as much as Jupiter’s moon Io, the most geologically active body in the solar system.
Illustration Credit: NASA’s Goddard Space Flight Center/Chris Smith/KRBwyle

Scientific Frontline: "At a Glance" Summary

• Main Discovery: The identification of LP 791-18 d, an Earth-sized exoplanet orbiting a red dwarf star 90 light-years away, which is likely covered in active volcanoes due to intense gravitational heating.
• Methodology: Researchers utilized photometric data from NASA’s Transiting Exoplanet Survey Satellite (TESS) and the retired Spitzer Space Telescope to detect the planet and analyze its orbit, specifically measuring transit timing variations caused by the gravitational tug of a larger neighboring planet, LP 791-18 c.
• Key Data: LP 791-18 d has a radius and mass consistent with Earth (approximately 1.03 Earth radii and 0.9 Earth masses) and orbits its host star every 2.8 days; its massive neighbor passes as close as 1.5 million kilometers, generating sufficient tidal friction to fuel volcanic activity comparable to Jupiter’s moon Io.
• Significance: This finding provides a rare analog for studying the long-term evolution of terrestrial planets and how extensive volcanic outgassing can sustain an atmosphere on tidally locked worlds, potentially allowing water to condense on the planet's dark side.
• Future Application: The planet serves as a prime target for the James Webb Space Telescope (JWST) to conduct atmospheric spectroscopy, aiming to detect potential biosignatures or volcanic gases like sulfur dioxide.
• Branch of Science: Exoplanetary Astronomy, Planetary Science.
• Additional Detail: The planet is tidally locked, meaning one side faces the star permanently, but the suspected global volcanic activity could transport heat and maintain an atmosphere across the night side.

Researchers develop new method to synthesize cannabis plant compound

Photo Credit: Matthew Brodeur

A group of researchers at Leipzig University has developed a new method for synthesizing cis-tetrahydrocannabinol (THC) – a natural substance found in the cannabis plant that produces the characteristic psychoactive effect and has many potential applications, including in the pharmaceutical industry. “Our strategy makes it possible to produce cis-tetrahydrocannabinoids and test them for their biological activity,” explains researcher Caroline Dorsch, who, together with Professor Christoph Schneider from the Institute of Organic Chemistry, has published her findings in the journal Angewandte Chemie.

She points out that until now there has been no way of synthesizing this structural class in a consistent way. With their simple, inexpensive and nature-based synthesis, the Leipzig researchers have for the first time made the substance class of cis-tetrahydrocannabinoids accessible for a broad range of applications. The researcher notes that because previous methods required many steps and large amounts of chemicals and solvents, their approach is clearly superior. The substance can be synthesized with high overall yields and excellent optical purities using the new method.  

Study Finds Carrying Pollen Heats Up Bumble Bees, Raising New Climate Change Questions

Photo Credit: Malia Naumchik.

A new study from North Carolina State University finds carrying pollen is a workout that significantly increases the body temperature of bumble bees. This new understanding of active bumble bee body temperatures raises questions about how these species will be impacted by a warmer world due to climate change.

Spend a bit of time at a nearby flower patch and you will spot a fuzzy bumble bee with yellow bumps on her back legs. These yellow bumps are solid packets of pollen that have been carefully collected during the bees’ foraging trip for transport back to their nests. And while bees may seem to move from flower to flower with ease, these pollen packets can weigh up to a third of their body weight. This new study found that – after accounting for environmental temperature and body size – the body temperature of bumble bees carrying pollen was significantly hotter than the temperature of bees that were empty-legged.

Specifically, the researchers found that bee body temperatures rose 0.07°C for every milligram of pollen that they carried, with fully laden bees being 2°C warmer than unladen bees.

Evidence of ‘pandemic brain’ in college students

“This study provides additional information to understand why students may have been having difficulty coming to class, focusing on class and getting things turned in – because there was this global event affecting every part of their lives,” lead researcher Melissa Buelow says.
Photo Credit: RF._.studio

Decision-making capabilities of college students – including some graduating this spring – were likely negatively affected by the COVID-19 pandemic, new research suggests.

Students in the small study conducted by researchers at The Ohio State University were less consistent in their decision making during the 2020 fall semester compared to students who had participated in similar research over several previous years.

The researchers compared responses to a hypothetical situation made by students during the pandemic to responses made by students in earlier studies. They found evidence that students in 2020 were more likely to cycle between going with their gut and more thoroughly mulling over their answers depending on how the scenario was described.

“Our theory is that feeling stressed by everything going on was limiting students’ resources to really evaluate the information that was presented to them,” said lead author Melissa Buelow, professor of psychology at Ohio State’s Newark campus. 

A better way to study ocean currents

Computer scientists at MIT joined forces with oceanographers to develop a machine-learning model that incorporates knowledge from fluid dynamics to generate more accurate predictions about the velocities of ocean currents. This figure shows drifting buoy trajectories in the Gulf of Mexico superimposed on surface currents. The red dots mark the buoys’ positions on March 9, 2016, and the tails are 14 days long.
Image Credits: Edward Ryan and Tamay Özgökmen from the University of Miami.

A new machine-learning model makes more accurate predictions about ocean currents, which could help with tracking plastic pollution and oil spills, and aid in search and rescue.

To study ocean currents, scientists release GPS-tagged buoys in the ocean and record their velocities to reconstruct the currents that transport them. These buoy data are also used to identify “divergences,” which are areas where water rises up from below the surface or sinks beneath it.

By accurately predicting currents and pinpointing divergences, scientists can more precisely forecast the weather, approximate how oil will spread after a spill, or measure energy transfer in the ocean. A new model that incorporates machine learning makes more accurate predictions than conventional models do, a new study reports.

A multidisciplinary research team including computer scientists at MIT and oceanographers has found that a standard statistical model typically used on buoy data can struggle to accurately reconstruct currents or identify divergences because it makes unrealistic assumptions about the behavior of water.

The researchers developed a new model that incorporates knowledge from fluid dynamics to better reflect the physics at work in ocean currents. They show that their method, which only requires a small amount of additional computational expense, is more accurate at predicting currents and identifying divergences than the traditional model.

Mystery of important blood pressure drugs solved

Prof. Daniel Fuster, M.D. Department for BioMedical Research (DBMR) of the University of Bern and Department of Nephrology and Hypertension, Inselspital, Bern University Hospital.
Photo Credit: Courtesy of Daniel Fuster

Diuretic drugs from the thiazide group have been used for 60 years to treat high blood pressure. But they also increase the risk of developing diabetes. Researchers at the University of Bern and Inselspital have now pinpointed the cause of this side effect and in the process also gained new insights into the development of diabetes.

High blood pressure is a global health problem. In Switzerland, one in two people over the age of 65 has high blood pressure. This has been shown to increase the risk of serious secondary diseases such as dementia, stroke, cerebral hemorrhage, heart attack, and kidney failure. According to estimates by the World Health Organization, for example, around 54 percent of strokes are a direct result of high blood pressure. "Accordingly, there is a great need for effective, and also inexpensive and widely available antihypertensive drugs - particularly in light of our aging society," explains Prof. Daniel Fuster, M.D., from the Department for BioMedical Research at the University of Bern (DBMR) and Head Physician at the Department of Nephrology and Hypertension at Inselspital, Bern University Hospital.

Curved spacetime in a quantum simulator

   In the background: the gravitational lens effect, an example of an effect explained by relativity. With quantum particles, analogous effects can be studied.
Image Credit: NASA / TU Wien

New techniques can answer questions that were previously inaccessible experimentally - including questions about the relationship between quantum mechanics and relativity.

The theory of relativity works well when you want to explain cosmic-scale phenomena - such as the gravitational waves created when black holes collide. Quantum theory works well when describing particle-scale phenomena - such as the behavior of individual electrons in an atom. But combining the two in a completely satisfactory way has yet to be achieved. The search for a "quantum theory of gravity" is considered one of the significant unsolved tasks of science.

This is partly because the mathematics in this field is highly complicated. At the same time, it is tough to perform suitable experiments:  One would have to create situations in which phenomena of both the relativity theory play an important role, for example, a spacetime curved by heavy masses, and at the same time, quantum effects become visible, for example the dual particle and wave nature of light.

Fauna return rapidly in planted eelgrass meadows

Comparison between newly planted eelgrass, to the left and eelgrass that is 15 months old, right.
Photo Credit: Eduardo Infantes

A study of eelgrass meadows planted by researchers from the University of Gothenburg shows that fauna return rapidly once the eelgrass has started to grow. Already after the second summer, the biodiversity in the planted meadow was almost the same as in old established eelgrass meadows.

Eelgrass meadows have declined heavily in southern Bohus county in recent decades and in many places have disappeared altogether. Researchers at the University of Gothenburg have been working on the restoration of eelgrass meadows for twelve years. These meadows are important for biodiversity, as the eelgrass serves as habitat or nursery for young cod, crabs and shrimps for example.  

In a new study, the researchers have evaluated how rapidly replanted eelgrass gets populated by various invertebrates. The study has been going on for over two years in a bay near Gåsö island just west of Skaftö in Bohus county, and the findings are very positive. The researchers counted the abundance of invertebrates that live or burrow in bottom sediments or on the surface of bottom sediments.

New transparent augmented reality display opens possibilities to see digital content in real-time

The flexible, transparent polymer-based material will advance how AR is used across a range of industries.
Photo Credit: Cesar Nicolas

The world's first flexible, transparent augmented reality (AR) display screen using 3D printing and low-cost materials has been created by researchers at the University of Melbourne, KDH Design Corporation and the Melbourne Centre for Nanofabrication (MCN). The development of the new display screen is set to advance how AR is used across a wide range of industries and applications.

AR technology overlays digital content onto the real world, enhancing the user's real-time perception and interaction with their environment. Until now, creating flexible AR technology that can adjust to different angles of light sources has been a challenge, as current mainstream AR manufacturing uses glass substrates, which must undergo photomasking, lamination, cutting, or etching microstructure patterns. These time-consuming processes are expensive, have a poor yield rate and are difficult to seamlessly integrate with product appearance designs.

UC Irvine research team identifies glycosylation enzyme critical in brain formation

Lisa Flanagan, professor of neurology
Photo Credit: Courtesy of University of California, Irvine

The MGAT5 glycosylation enzyme plays a crucial role in brain development, according to a study by University of California, Irvine researchers, a discovery that may contribute to new therapeutic purposes for neural stem cells.

Neurons, astrocytes and oligodendrocytes are the final mature cells of the brain and spinal cord formed by neural stem cells. Each has distinct and key functions. Neurons transmit signals, astrocytes help modify those signals, and oligodendrocytes keep the signals from degrading. When any cells make proteins or fats that end up on the cell surface, they often add small sugar molecules. The team tested whether this internal process – called glycosylation – affects how neural stem cells form mature brain cells.

The study, published in the journal Stem Cell Reports, found that during glycosylation, the MGAT5 enzyme significantly regulates the formation of neurons and astrocytes from neural stem cells. Neural stem cells that don’t have MGAT5 make more neurons and fewer astrocytes during the very early stages of brain development, altering its structure. These changes may contribute to later aberrant behavior patterns, including abnormal social interactions and repetitive actions.

Warm Ice Age” Changed Climate Cycles

The “Joides Resolution” research vessel – in the port of Lisbon – has been used since 1985 as part of the International Ocean Discovery Program for scientific drilling. The drill cores used in the current “warm ice age” study were taken during an expedition in the Gulf of Cádiz and off of southern Portugal. 
Photo Credit:  André Bahr

Earth scientists identify pivotal step in the Earth’s later climate development

Approximately 700,000 years ago, a “warm ice age” permanently changed the climate cycles on Earth. Contemporaneous with this exceptionally warm and moist period, the polar glaciers greatly expanded. A European research team including Earth scientists from Heidelberg University used recently acquired geological data in combination with computer simulations to identify this seemingly paradoxical connection. According to the researchers, this profound change in the Earth’s climate was responsible for the change in the climate cycles, thus representing a critical step in the later climate evolution of our planet.

Contraception, evolution and the genetic maintenance of same-sex sexual behavior

A gene is a basic unit of heredity. It is a segment of DNA that codes for a specific protein or RNA molecule. Genes are responsible for passing on traits from parents to their offspring. 
Image Credit: THAVIS 3D

Evolution depends on genes being passed down through the generations via reproduction, and same-sex sexual behavior does not result in offspring.

So, why haven’t the many genes associated with same-sex sexual behavior, known as SSB-associated genes, been purged from the human genome over time? It’s a question that has perplexed scientists for decades, one that’s explored anew in a Proceedings of the National Academy of Sciences study by two University of Michigan biologists.

One possible explanation for the persistence of SSB-associated genes is that they have more than one function, a concept called pleiotropy. Perhaps SSB-associated genes are advantageous to heterosexuals in some way, helping them to have more children.

Support for this idea includes a 2021 Nature Human Behaviour study by University of Queensland biologist Brendan Zietsch and colleagues. They presented evidence that heterosexuals carrying SSB-associated genes have more sexual partners than those not carrying the genes. This could confer an evolutionary advantage, because more sexual partners could translate into more children, according to the Zietsch et al. study.

Scientists use X-ray beams to determine role of zinc in development of ovarian follicles

Elemental map of zinc measured by synchrotron-based X-ray fluorescence microscopy demonstrates the increase in total zinc content, and the differential distribution of zinc in ovarian follicles during primordial-through-secondary-stage development. The color scale bar represents the minimum and maximum zinc contents (µg/cm2). Scale bar=10 μm.
Image Credit: NIH/Yu-Ying Chen

To make a baby, first you need an egg. To have an egg, there needs to be a follicle. And in the very beginning of follicle development, there needs to be zinc.

The last of those statements represents the new findings reported recently by a team of researchers from Michigan State University, Northwestern University and the U.S. Department of Energy’s (DOE) Argonne National Laboratory. The research builds upon earlier work looking at the role of zinc in fertilization and uncovers the importance of the metal earlier in the process of ovulation.

The results were reported in a paper in the Journal of Biological Chemistry that looked at the role of zinc in follicle development. The researchers, led by Teresa Woodruff and Tom O’Halloran of Michigan State University, used the Bionanoprobe at Argonne’s Advanced Photon Source (APS) to examine zinc and other trace elements in the egg cell itself as well as surrounding somatic cells.

Insight into brain’s waste clearing system may shed light on brain diseases

The image shows a microscopic image revealing the enhanced glymphatic transport of an intranasally delivered tracer (red), achieved using ultrasound combined with microbubbles.
Image Credit: Chen lab

Like the lymphatic system in the body, the glymphatic system in the brain clears metabolic waste and distributes nutrients and other important compounds. Impairments in this system may contribute to brain diseases, such as neurodegenerative diseases and stroke.

A team of researchers in the McKelvey School of Engineering at Washington University in St. Louis has found a noninvasive and nonpharmaceutical method to influence glymphatic transport using focused ultrasound, opening the opportunity to use the method to further study brain diseases and brain function. Results of the work are published in Proceedings of the National Academy of Sciences May 15, 2023.

Hong Chen, associate professor of biomedical engineering in McKelvey Engineering and of neurological surgery in the School of Medicine, and her team, including Dezhuang (Summer) Ye, a postdoctoral research associate, and Si (Stacie) Chen, a former postdoctoral research associate, found the first direct evidence that focused ultrasound, combined with circulating microbubbles — a technique they call FUSMB — could mechanically enhance glymphatic transport in the mouse brain. 

Focused ultrasound can penetrate the scalp and skull to reach the brain and precisely target a defined region within the brain. In previous work, Chen’s team found that microbubbles injected into the bloodstream amplify the effects of the ultrasound waves on the blood vessels and generate a pumping effect, which helps with the accumulation of intranasally-delivered agents in the brain, such as drugs or gene therapy treatments.