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Category: evolution – Page 32

Dr. Fan Liu: “Thanks to this very high precision analysis, we can see chemical differences between the twins. This provides very strong evidence that one of the stars has swallowed planets or planetary material and changed its composition.”

Can stars eat planets? This is what a recent study published in Nature hopes to address as a team of international researchers led by ASTRO 3D researchers investigated how some pairs of twin stars possess different compositions, which contradicts longstanding theories that they should possess similar compositions, hence the same twin stars. However, astronomers now hypothesize the compositional differences could be due to one of the twin stars devouring planets that orbit them. This study holds the potential to help astronomers better understand the formation and evolution of planetary systems and the mechanisms behind them, as well.

For the study, the team used a combination of the 6.5-meter Magellan Telescope, the European Southern Observatory’s Very Large Telescope, and the 10-meter Keck Telescope to collect data on 91 twin stars to ascertain their chemical compositions, and specifically the similarity of their compositions. In the end, the team discovered that approximately eight percent (7−8 twin stars) exhibited differences in their compositions, with the team hypothesizing that this was due to one of the stars ingesting one of their orbiting planets. Additionally, they found that the differing pairs were all main sequence stars, meaning they’re average-aged and conducting their fusion at their full potential. For context, our Sun is a main sequence star.

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Researchers report the birth of a ~2-billion-year-old orphan gene following #planetary #oxygenation, and how this humble beginning shaped the global planetary #ecosystem.

From so simple, a beginning: https://oup.silverchair-cdn.com/UI/app/svg/i.svg?versionId=192134

Abstract. Molecular innovations within key metabolisms can have profound impacts on element cycling and ecological distribution. Yet, much of the molecular foundations of early evolved enzymes and metabolisms are unknown. Here, we bring one such mystery to relief by probing the birth and evolution of the G-subunit protein, an integral component of certain members of the nitrogenase family, the only enzymes capable of biological nitrogen fixation. The G-subunit is a Paleoproterozoic-age orphan protein that appears more than 1 billion years after the origin of nitrogenases. We show that the G-subunit arose with novel nitrogenase metal dependence and the ecological expansion of nitrogen-fixing microbes following the transition in enviromental metal availabilities and atmospheric oxygenation that began ∼2.5 billion years ago. We identify molecular features that suggest early G-subunit proteins mediated cofactor or protein interactions required for novel metal dependency, priming ancient nitrogenases and their hosts to exploit these newly diversified geochemical environments. We further examined the degree of functional specialization in G-subunit evolution with extant and ancestral homologs using laboratory reconstruction experiments. Our results indicate that permanent recruitment of the orphan protein depended on the prior establishment of conserved molecular features and showcase how contingent evolutionary novelties might shape ecologically important microbial innovations.

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Humans have always been storytellers. Weaving tales, exchanging knowledge, and planning for the future are quintessentially human endeavors that have shaped the course of our species. But when did this remarkable ability to communicate through language first emerge? Recent research suggests a far earlier origin than previously thought, shedding light on the fascinating journey of human evolution.

Dr. Steven Mithen, an esteemed archaeologist from the University of Reading, has delved deep into the annals of prehistory to uncover the roots of human speech. Contrary to conventional wisdom, which pegged the advent of language to around 200,000 years ago, Mithen’s groundbreaking analysis suggests a much more ancient beginning—approximately 1.6 million years ago, in the cradle of humanity, somewhere nestled in the vast expanse of eastern or southern Africa.

In his quest to unveil the origins of language, Mithen meticulously examined a plethora of evidence spanning archaeology, genetics, neurology, and linguistics. The culmination of his research paints a vivid picture of our ancestors’ journey towards spoken communication.

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Brain organoids have become increasingly used systems allowing 3D-modeling of human brain development, evolution, and disease. To be able to make full use of these modeling systems, researchers have developed a growing toolkit of genetic modification techniques. These techniques can be applied to mature brain organoids or to the preceding embryoid bodies (EBs) and founding cells. This review will describe techniques used for transient and stable genetic modification of brain organoids and discuss their current use and respective advantages and disadvantages. Transient approaches include adeno-associated virus (AAV) and electroporation-based techniques, whereas stable genetic modification approaches make use of lentivirus (including viral stamping), transposon and CRISPR/Cas9 systems. Finally, an outlook as to likely future developments and applications regarding genetic modifications of brain organoids will be presented.

The development of brain organoids (Kadoshima et al., 2013; Lancaster et al., 2013) has opened up new ways to study brain development and evolution as well as neurodevelopmental disorders. Brain organoids are multicellular 3D structures that mimic certain aspects of the cytoarchitecture and cell-type composition of certain brain regions over a particular developmental time window (Heide et al., 2018). These structures are generated by differentiation of induced pluripotent stem cells (iPSCs) or embryonic stem cells (ESCs) into embryoid bodies followed by, or combined, with neural induction (Kadoshima et al., 2013; Lancaster et al., 2013). In principle, two different classes of brain organoid protocols can be distinguished, namely: (i) the self-patterning protocols which produce whole-brain organoids; and (ii) the pre-patterning protocols which produce brain region-specific organoids (Heide et al., 2018).

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Scientists from China and Japan have identified unique features of the flow field in the lower mantle. Through their study of seismic anisotropy in the upper section of the lower mantle beneath the Philippine Sea Plate, they discovered that the ancient lower mantle flow field is still preserved there.

The study was published in Nature Geoscience.

The lower mantle is an important layer of the Earth and may play an important role in the evolution and material cycling of Earth’s interior. It is generally believed to be not only the final destination of subducted slabs, but also the birthplace of mantle plumes, which are two major styles in the evolution and material cycling of the Earth’s surface and interior. However, our knowledge of the characteristics of the flow field and geodynamics of the lower mantle is still deficient.

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Everyone loves a two-for-one deal—even physicists looking to tackle unanswered questions about the cosmos. Now, scientists at the Department of Energy’s SLAC National Accelerator Laboratory are getting just such a twofer: Particle detectors originally developed to look for dark matter are now in a position to be included aboard the Line Emission Mapper (LEM), a space-based X-ray probe mission proposed for the 2030s.

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Human brains preserve in diverse environments for at least 12 000 years—new research in Proceedings B this week: https://royalsocietypublishing.org/doi/10.1098/rspb.2023.

Soft tissue preservation in the geological record is relatively rare, and when an archaeologist digs a human skull out of the…

The brain is thought to be among the first human organs to decompose after death. The discovery of brains preserved in the archaeological record is therefore regarded as unusual. Although mechanisms such as dehydration, freezing, saponification, and tanning are known to allow for the preservation of the brain on short time scales in association with other soft tissues (≲4000 years), discoveries of older brains, especially in the absence of other soft tissues, are rare. Here, we collated an archive of more than 4,400 human brains preserved in the archaeological record across approximately 12 000 years, more than 1,300 of which constitute the only soft tissue preserved amongst otherwise skeletonized remains. We found that brains of this type persist on time scales exceeding those preserved by other means, which suggests an unknown mechanism may be responsible for preservation particular to the central nervous system. The untapped archive of preserved ancient brains represents an opportunity for bioarchaeological studies of human evolution, health and disease.

Since the mid-17th century, more than 4,400 human brains have been unearthed from the last 12 000 years of the archaeological record, over 1,300 of which are preserved among otherwise skeletonized remains. Despite this volume of finds, the perception remains that preserved brains represent ‘unique’ or ‘extremely rare’ discoveries [1]. Human soft tissues are understood to persist through time by well-characterized mechanisms of preservation such as dehydration, freezing and tanning, brought about by anthropogenic (i.e. the result of deliberate human intervention) or naturally occurring factors. Thus, it is not surprising that the brain endures alongside other internal organs where there is extensive soft tissue preservation.

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In Verlinde’s picture of emergent gravity, as soon as you enter low-density regions — basically, anything outside the solar system — gravity behaves differently than we would expect from Einstein’s theory of general relativity. At large scales, there is a natural inward pull to space itself, which forces matter to clump up more tightly than it otherwise would.

This idea was exciting because it allowed astronomers to find a way to test this new theory. Observers could take this new theory of gravity and put it in models of galaxy structure and evolution to find differences between it and models of dark matter.

Over the years, however, the experimental results have been mixed. Some early tests favored emergent gravity over dark matter when it came to the rotation rates of stars. But more recent observations haven’t found an advantage. And dark matter can also explain much more than galaxy rotation rates; tests within galaxy clusters have found emergent gravity coming up short.

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Through Broad’s Scientists in the Classroom program, Broad researchers visit every 8th grade classroom in Cambridge each year to talk about genetics and evolution.

Every summer, 18 high school students spend six weeks at Broad working side-by-side with mentors on cutting-edge research.

In November 2022, Broad’s Genomics Platform sequenced its 500,000th whole human genome, a mere four years after sequencing its 100,000th.

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