‘Assembly theory’ aims to explain evolution without biology. Is it a dazzling breakthrough or an attempt to answer questions nobody asked?
Cell division is a crucial process for all life forms, from bacteria to blue whales, enabling growth, reproduction, and the continuation of species. Despite its universal nature, the methods of cell division vary significantly across organisms. A recent study by EMBL Heidelberg’s Dey group, along with their collaborators and published in Nature, investigates the evolution of cell division methods in organisms closely related to fungi and animals. For the first time, this research demonstrates the connection between an organism’s life cycle and its cell division techniques.
Despite last sharing a common ancestor over a billion years ago, animals and fungi are similar in many ways. Both belong to a broader group called ‘eukaryotes’ – organisms whose cells store their genetic material inside a closed compartment called the ‘nucleus’. The two differ, however, in how they carry out many physiological processes, including the most common type of cell division – mitosis.
Most animal cells undergo ‘open’ mitosis, in which the nuclear envelope – the two-layered membrane separating the nucleus from the rest of the cell – breaks down when cell division begins. However, most fungi use a different form of cell division – called ‘closed’ mitosis – in which the nuclear envelope remains intact throughout the division process. However, very little is known about why or how these two distinct modes of cell division evolved and what factors determine which mode would be predominantly followed by a particular species.
The size and surface area of the mammalian brain are thought to be critical determinants of intellectual ability. Recent studies show that development of the gyrated human neocortex involves a lineage of neural stem and transit-amplifying cells that forms the outer subventricular zone (OSVZ), a proliferative region outside the ventricular epithelium. We discuss how proliferation of cells within the OSVZ expands the neocortex by increasing neuron number and modifying the trajectory of migrating neurons.
In recent years, my lab — or perhaps it’s just me — has developed an obsession with evolutionary transitions. The view that every gene originates from an ancestral state and undergoes impactful changes through its evolutionary journey, whether it’s the gain or loss of an activity or function. The challenge lies in meticulously mapping out these key evolutionary innovations that have significantly influenced function. Addressing this challenge is not merely interesting but absolutely essential in biology. Our aim as biologists transcends understanding how biological systems operate; we seek to unravel how they came to be. And the two questions are more connected than many think.
This post stems from my observation that molecular biologists sometimes appear indifferent to evolution, questioning its relevance to mechanistic research. It baffles me why the centrality of evolution in biology isn’t apparent to some. Maybe they’ve never taken a course on the subject, or perhaps they’ve never fully appreciated the profound concept that every organism and every gene is connected through an unbroken chain of descent to countless ancestors. This perspective holds profound implications for mechanistic molecular biology.
If you already appreciate the link between evolutionary biology and molecular mechanisms, you might find this post to be music to your ears. However, if you’re among those who question the value of evolutionary biology, I encourage you to stay with me; you might discover its significance in ways you hadn’t considered before.
Researchers have developed a new method that uses attosecond core-level spectroscopy to capture molecular dynamics in real time.
The mechanisms behind chemical reactions are complex, involving many dynamic processes that affect both the electrons and the nuclei of the involved atoms. Frequently, the strongly coupled electron and nuclear dynamics trigger radiation-less relaxation processes known as conical intersections. These dynamics underpin many significant biological and chemical functions but are notoriously difficult to detect experimentally.
The challenge in studying these dynamics stems from the difficulty of tracing the nuclear and electronic motion simultaneously. Their dynamics are intertwined and occur on ultrafast timescales, which has made capturing the molecular dynamical evolution in real time a major challenge for both physicists and chemists in recent years.
If trillions of tiny bits of consciousness are floating around inside you, it could change how we think about life.
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Only about consciousness can we be 100 percent sure. That consciousness exists almost everyone agrees. What consciousness means—that’s where arguments and disputations arise. Must consciousness have ‘meaning’? Or can consciousness be a random accident, selected by evolution, the ‘foam on the waves’ of brain activity. But consciousness seems so radically vital.
Continue reading “Ned Block — What’s the Meaning of Consciousness?” »
“Many primary atmospheres of those planets will probably be dominated by hydrocarbon compounds and not so much by oxygen-rich gases such as water and carbon dioxide,” said Dr. Thomas Henning.
Can rocky planets form around stars smaller than our Sun, also called low-mass stars? This is what a recent study published in Science hopes to address as a team of international researchers investigated the chemical properties of an exoplanetary system orbiting the star, ISO-Chal 147, which is located approximately 600 light-years from Earth and whose star has a mass of 11 percent of our Sun with age estimates between 1 to 2 million years old. For context, our Sun is approximately 4.5 billion years old. This study holds the potential to help astronomers better understand the formation and evolution of young exoplanetary systems and their potential to host rocky planets.
For the study, the researchers used the Mid-Infrared Instrument (MIRI) on the NASA’s James Webb Space Telescope (JWST) to identify carbon-bearing molecules at temperatures of approximately 30 degrees Celsius (86 degrees Fahrenheit) within the protoplanetary disk forming around the young star. However, the team also found these molecules did not possess compounds containing oxygen, meaning the system might not have water or carbon dioxide, which are typically found in systems surrounding stars like our Sun.
Continue reading “Implications for Rocky Planet Formation Around Low-Mass Stars” »
NASA’s Lucy spacecraft’s recent exploration of asteroid Dinkinesh not only highlighted the asteroid’s internal complexities but also led to a fascinating discovery: the formation of a double moon, Selam. This rare configuration, known as a contact binary, formed from debris orbiting Dinkinesh after a significant geological event. Credit: NASA/SwRI/Johns Hopkins APL/NOIRLab.
NASA ’s Lucy spacecraft’s November 2023 flyby of asteroid Dinkinesh revealed significant geological features indicating its internal strength and complex history. Images showed a trough, a ridge, and a contact binary satellite, Selam. These findings, suggesting that Dinkinesh responded dynamically to stress over millions of years, help scientists understand the formation and evolution of small bodies in the solar system.
Continue reading “Twin Moons of Dinkinesh: NASA’s Lucy Unveils a Surprising Discovery” »
One of Earth’s most consequential bursts of biodiversity—a 30-million-year period of explosive evolutionary changes spawning innumerable new species —may have the most modest of creatures to thank for the vital stage in life’s history: worms.
The digging and burrowing of prehistoric worms and other invertebrates along ocean bottoms sparked a chain of events that released oxygen into the ocean and atmosphere and helped kick-start what is known as the Great Ordovician Biodiversification Event, roughly 480 million years ago, according to new findings Johns Hopkins University researchers published in the journal Geochimica et Cosmochimica Acta.
“It’s really incredible to think how such small animals, ones that don’t even exist today, could alter the course of evolutionary history in such a profound way,” said senior author Maya Gomes, an assistant professor in the Department of Earth and Planetary Sciences. “With this work, we’ll be able to examine the chemistry of early oceans and reinterpret parts of the geological record.”
