. Scientific Frontline

Wednesday, May 17, 2023

Scales or feathers? It all comes down to a few genes

From left to right: Rory Cooper, a post-doctoral researcher in Michel Milinkovitch’s laboratory, and Michel Milinkovitch, professor in the Department of Genetics and Evolution at the Faculty of Science of the UNIGE. 
Photo Credit: UNIGE

Scales, spines, feathers and hair are examples of vertebrate skin appendages, which constitute a remarkably diverse group of micro-organs. Despite their natural multitude of forms, these appendages share early developmental processes at the embryonic stage. Two researchers from the University of Geneva (UNIGE) have discovered how to permanently transform the scales that normally cover the feet of chickens into feathers, by specifically modifying the expression of certain genes. These results, published in the journal Science Advances, open new perspectives for studying mechanisms that have enabled radical evolutionary transitions in form among species.

The skin of terrestrial vertebrates is adorned with diverse keratinized appendages, such as hair, feathers, and scales. Despite the diversity of forms within and among species, the embryonic development of skin appendages typically begins in a very similar way. Indeed, all of these structures develop from cells that produce a localized thickening on the skin surface and express particular genes. One of these genes, called Sonic hedgehog (Shh), controls a signaling pathway - a communication system that allows the transmission of messages within and between cells. Shh signaling is involved in the development of diverse structures, including the neural tube, limb buds and skin appendages.

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

Imagine an Earth-sized planet that’s not at all Earth-like. Half this world is locked in permanent daytime, the other half in permanent night, and it’s carpeted with active volcanoes. Astronomers have discovered that planet. 

The planet, named LP 791-18d, orbits a small red dwarf star about 90 light years away. Volcanic activity makes the discovery particularly notable for astronomers because volcanism facilitates interaction between a world’s interior and its exterior.

“Why is volcanism important? It is the major source contributing to a planetary atmosphere, and with an atmosphere you could have surface liquid water — a requirement for sustaining life as we know it,” said UC Riverside astrophysicist Stephen Kane. 

Astronomers already knew about two other worlds in this star system, LP 791-18b and c. The outer planet, c, is about 2.5 times Earth’s size, and nearly nine times its mass. 

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.

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