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Category: evolution – Page 84

The structure of how DNA is stored in archaea makes a significant difference to how quickly it evolves, according to a new study by Indiana University researchers.

The study, led by molecular biologist Stephen Bell, Distinguished Professor and chair of the College of Arts and Sciences’ Department of Molecular and Cellular Biochemistry at Indiana University (IU) Bloomington, was recently published in Nature Microbiology. Its findings have the potential to impact research on the treatment of genetic diseases such as cancer.

“The most exciting thing we revealed is the idea that the shape of a DNA molecule can affect its ability to change,” Bell said. “In the early 20th century, modernist architecture had the idea that the form of a building should follow its function. But what we’re seeing in these organisms is that over time, form is actually affecting . How DNA is structured can change it, creating an evolutionary feedback loop.”

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Though the planets are outside of their star’s habitable zone, as they orbit too closely, “there might be more planets in the system,” according to Avi Shporer, one of the scientists involved in the new study. “There are many multiplanet systems hosting five or six planets, especially around small stars like this one. Hopefully, we will find more, and one might be in the habitable zone. That’s optimistic thinking.”

Either way, the multiplanet system will likely be a focal point for future studies, shedding new insight into planetary formation and the evolution of alien worlds, helping the astronomical community better understand how our own planet came into existence.

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The ancestors of some of the largest galaxy clusters have been hiding in plain sight. New work led by Carnegie’s Andrew Newman demonstrates a new technique for identifying the precursors of the most extreme galactic environments. The team’s findings are published in Nature.

Like all of us, are shaped and molded by their surroundings. To obtain a complete picture of the various physical influences on a galaxy’s lifecycle, it’s crucial to trace the emergence of properties caused by as they arise.

“We’ve known for a long time that the colors, masses, and shapes of galaxies depend on their cosmic environment, but there’s a lot we don’t know about when and how those differences appeared,” Newman said.

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A detailed analysis of the composition and motion of more than 500 stars has revealed conclusive evidence of an ancient collision between Andromeda and a neighboring galaxy. The findings, which improve our understanding of the events that shape galaxy evolution, were presented by Carnegie’s Ivanna Escala Monday at the meeting of the American Astronomical Society.

Galaxies grow by accreting material from nearby objects—other galaxies and dense clumps of stars called —often in the aftermath of a catastrophic crash. And these events leave behind relics in the form of stellar associations that astronomers call tidal features. This can include elongated streams or arcing shells moving around the surviving galaxy. Studying these phenomena can help us understand a galaxy’s history and the forces that shaped its appearance and makeup.

“The remnants of each crash can be identified by studying the movement of the stars and their chemical compositions. Together this information serves as a kind of fingerprint that identifies stars that joined a galaxy in a collision,” Escala explained.

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Circa 2021 Evidence of string theory by black holes as fuzzballs.

Abstract: We examine an interesting set of recent proposals describing a ‘wormhole paradigm’ for black holes. These proposals require that in some effective variables, semiclassical low-energy dynamics emerges at the horizon. We prove the ‘effective small corrections theorem’ to show that such an effective horizon behavior is not compatible with the requirement that the black hole radiate like a piece of coal as seen from outside. This theorem thus concretizes the fact that the proposals within the wormhole paradigm require some nonlocality linking the hole and its distant radiation. We try to illustrate various proposals for nonlocality by making simple bit models to encode the nonlocal effects. In each case, we find either nonunitarity of evolution in the black hole interior or a nonlocal Hamiltonian interaction between the hole and infinity; such an interaction is not present for burning coal. We examine recent arguments about the Page curve and observe that the quantity that is argued to follow the Page curve of a normal body is not the entanglement entropy but a different quantity. It has been suggested that this replacement of the quantity to be computed arises from the possibility of topology change in gravity which can generate replica wormholes. We examine the role of topology change in quantum gravity but do not find any source of connections between different replica copies in the path integral for the Rényi entropy. We also contrast the wormhole paradigm with the fuzzball paradigm, where the fuzzball does radiate like a piece of coal. Just as in the case of a piece of coal, the fuzzball does not have low-energy semiclassical dynamics at its surface at energies $E\sim T$ (effective dynamics at energies $E\gg T$ is possible under the conjecture of fuzzball complementarity, but these $E\gg T$ modes have no relevance to the Page curve or the information paradox).

From: Marcel Hughes [view email]

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Scientists at the Foundation for Applied Molecular Evolution announced today that ribonucleic acid (RNA), an analog of DNA that was likely the first genetic material for life, spontaneously forms on basalt lava glass. Such glass was abundant on Earth 4.35 billion years ago. Similar basalts of this antiquity survive on Mars today.

More information:

Craig A. Jerome et al, Catalytic Synthesis of Polyribonucleic Acid on Prebiotic Rock Glasses, Astrobiology (2022). DOI: 10.1089/ast.2022.

Hyo-Joong Kim et al, Prebiotic stereoselective synthesis of purine and noncanonical pyrimidine nucleotide from nucleobases and phosphorylated carbohydrates, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.

Continue reading “Scientists announce a breakthrough in determining life’s origin on Earth—and maybe Mars” | >

Electric organs help electric fish, such as the electric eel, do all sorts of amazing things: They send and receive signals that are akin to bird songs, helping them to recognize other electric fish by species, sex and even individual. A new study in Science Advances explains how small genetic changes enabled electric fish to evolve electric organs. The finding might also help scientists pinpoint the genetic mutations behind some human diseases.

Evolution took advantage of a quirk of genetics to develop electric organs. All fish have duplicate versions of the same gene that produces tiny muscle motors, called . To evolve electric organs, electric fish turned off one duplicate of the channel gene in muscles and turned it on in other cells. The tiny motors that typically make muscles contract were repurposed to generate electric signals, and voila! A new organ with some astonishing capabilities was born.

“This is exciting because we can see how a small change in the gene can completely change where it’s expressed,” said Harold Zakon, professor of neuroscience and integrative biology at The University of Texas at Austin and corresponding author of the study.

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Can quantum science supercharge genetics? | Jim Al-Khalili for Big Think.

This interview is an episode from The Well, our new publication about ideas that inspire a life well-lived, created with the John Templeton Foundation.

Up next ► Where science fails, according to a physicist https://youtu.be/4hpdKQB2ruc.

Continue reading “What if quantum physics could eradicate illness? | Jim Al-Khalili for Big Think” | >

Earth’s interior is a far from quiet place. Deep below our surface activities, the planet rumbles with activity, from plate tectonics to convection currents that circulate through the hot magmatic fluids far underneath the crust.

Now scientists studying satellite data of Earth have identified something inside Earth we’ve never seen before: a new type of magnetic wave that sweeps around the surface of our planet’s core, every seven years.

This discovery could offer insight into how Earth’s magnetic field is generated, and provide clues of our planet’s thermal history and evolution – that is, the gradual cooling of the planetary interior.

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