Life's first molecule: Borate boosts its formation, finds study

Amazing stuff!

Notice the abstract speaks of a six step process, but it lists only five steps! The significance and abstract also contained some misspellings or ambiguous spellings (which I corrected).

"One surprising discovery made by the researchers was that the mineral borate, which was expected to interfere with essential prebiotic processes by latching onto key ingredients and preventing further reactions, actually had the opposite effect. Instead, borate helped with the chemical reactions by sweeping away unwanted byproducts and maintaining the pH levels required for RNA synthesis. ..."

From the significance and abstract:

"Significance

RNA may have been the first informational molecule to support Darwinian evolution, and life, on Hadean Earth and/or Noachian Mars. Thus, any model that produces RNA from simple organic molecules is relevant to understanding how life emerged under an “RNA First” hypothesis.

Here, we analyze one model to form prebiotic RNA, finding that all steps are compatible with each other and with noncontroversial geochemical and geodynamical models.

Perhaps coincidentally, these steps most likely occurred 4.3 billion years ago, ca. 100 Mya before some molecular clocks approximate the divergence of the kingdoms of Earth life (ca. 4.2 Ga), and 200 Mya before isotopically “light” carbon is seen in 4.1 Ga zircons, perhaps the oldest trace of life on Earth.

Abstract

Models for prebiotic synthesis often have many steps, each separately validated by laboratory experiments. The challenge then asks whether these steps work together in natural geological environments, absent human intervention.

Here, we analyze a six-step Discontinuous Synthesis Model (DSM) for the prebiotic formation of RNA, proposed to be the first informational molecule to support Darwinian evolution, and life, on Earth and/or Mars.

DSM requires that borate in multiple steps guide the formation of pentoses from simple carbohydrates and control phosphorylation, in all cases by binding adjacent HO-groups on key intermediates. However, adjacent HO-groups must react in two other steps, which borate might inhibit.

Experiments here show that borate does not inhibit these two other steps, but rather facilitates them. This makes the six-step DSM a “no human intervention” route from simple precursors (1 to 3 carbons, 0 to 2 nitrogens) to oligomeric RNA with predominantly 3’,5’-linkages at least 6 nucleotides long, but possibly much longer.

The process
i) exploits privileged chemistry in
ii) intermittently irrigated aquifers constrained by basalt that
iii) have borate
iv) above a redox-neutral mantle
v) having access to an atmosphere transiently reduced by a Vesta-sized impactor.

In a possible coincidence, such an impact occurred most likely ca. 4.3 billion years ago (Ga), ~100 Mya before some molecular clocks date the divergence of the three kingdoms of life on Earth (4.2 Ga), and ca. 200 Mya before isotopically “light” carbon is reported in zircons dated at 4.1 Ga. This carbon may be the oldest trace of life ever proposed."

Life's first molecule: Borate boosts its formation, finds study

Interstep compatibility of a model for the prebiotic synthesis of RNA consistent with Hadean natural history (no public access)

At least two vibrant, colorful lichen species have specialized to colonize on exposed dinosaur bones

Amazing stuff!

"... Now, paleontologists and remote sensing scientists working in Dinosaur Provincial Park in Alberta, Canada have identified an unlikely—and vibrantly colored—ally. 

For decades, researchers have noted anecdotally that bright orange lichens tend to grow on exposed dinosaur bones, serving as a kind of beacon for fossil hunters. ... Back in 1980, paleontologist Darren H. Tanke even speculated that lichen growing on bones belonging to Centrosaurus might be detectable by satellites.

The study authors found that two lichen species—Rusavskia elegans and Xanthomendoza trachyphylla—colonized as much as 50% of exposed fossil bones but left the surrounding rock fragments alone. Dinosaur bones, the team reports, likely provide the alkaline, calcium-rich, and porous substrates these species need to thrive in semi-arid environments like the Canadian Badlands. These lichen-covered fossils create distinctive spectral signatures, which can be detected from 30 meters above the ground using specialized drones. ..."

From the abstract:

"Advances in palaeontology and evolutionary biology are often linked to the discovery of new fossils, yet these discoveries are typically serendipitous.

Here, we report that lichens can serve as biological indicators of vertebrate fossils in western North America and can be identified using remote sensing. Lichens are symbioses between fungi and algae (and/or cyanobacteria) that play important ecological roles and colonise many substrates, including fossils. Preferential colonisation of dinosaur bones by lichen with vibrant orange pigmentation (Figure 1A,B) has been recognised anecdotally for decades (Darren H. Tanke, personal communication).

We found that the spectral reflectance profiles of these lichen pigments and the preferential association between modern lichens and ancient bones can be used to detect dinosaur fossils by remote sensing, for which we propose new spectral indices."

ScienceAdviser

Lichens and drones reveal dinosaur bones (open access)

Orange marks the bone.

Figure 1 Preferential colonisation of dinosaur bones by lichens with distinctive spectral profiles and their detection in drone (RPAS) images.

More than 500 mammoth and more discovered at one site in Mexico

Amazing stuff!

"When excavators dug into the Santa Lucía military base north of Mexico City to build a new international airport, ... they cracked open one of the biggest paleontological jackpots ever found in the country. Tusks, skulls, and bones emerged by the thousands: camels, horses, saber-toothed cats, and even a lone human. But the true treasure were the mammoths—more than 500 Columbian mammoths, the giant cousins of the woolly species, had been preserved in the mud of an ancient lake.

Normally, we picture mammoths stomping through the Siberian tundra. These, however, were tropical beasts living high on the Mexican plateau. Against the odds, scientists managed to extract DNA from 61 of their teeth—the first genetic data ever recovered from mammoths that lived this far south. The results, published yesterday in Science, show that Mexican mammoths formed their own lineage, genetically distinct from northern herds.

Their genes suggest that their adaptability—eating not just grasses but shrubs and trees—helped them resist climate swings. But by about 11,000 years ago, these giants had vanished ..."

"... By 2022, ...  team had amassed more than 50,000 Pleistocene bones from just 3700 hectares. Among them are at least 500 mammoths, 200 camels, 70 horses, 15 giant ground sloths, as well as the remains of dire wolves, saber-toothed cats, bison, armadillos, birds, freshwater snails—and one human skeleton. ..."

From the abstract:

"Paleogenomic studies suggest that Mammuthus columbi derives from an ancient hybridization between Mammuthus primigenius and Mammuthus trogontherii. While its habitat spanned from North to Central America, available genetic data are limited to temperate regions, leaving gaps in knowledge of the species’ demographic history on the continent.

In this study, we generated 61 capture-enriched M. columbi mitogenomes from the Basin of Mexico, in Central Mexico. Our analysis reveals that these mitogenomes belong to a mitochondrial lineage distinct from other North American mammoths. These divergent mitogenomes suggest a deep population structure in their ancestors, and challenge prior assumptions based on geographically restricted samples. Our findings underscore the importance of wider spatial sampling to reconstruct mammoths’ evolutionary history and demonstrate the feasibility of studying megafauna from tropical latitudes."

ScienceAdviser

Mammoths in Mexico? Huge bone trove reveals giant beasts thrived in warmth, too (no public access)

Columbian mammoth mitogenomes from Mexico uncover the species’ complex evolutionary history (open access)

Fig. 1. Sampling sites of the specimens analyzed in this study.

New dinosaur is unlike anything we've ever found | Unique armoured dinosaur discovered in Morocco

Very recommendable! 

The oldest ever evidence of butterflies and moths dating to about 240 million years ago

Amazing stuff! What a story! Poop with scales!

"Nearly 250 million years ago in what is now northwestern Argentina, a hippo-sized herbivore lumbered about and gobbled up all sorts of plants, along with any fungi, insects, and other critters that were coincidentally mixed in among the green. Eventually that creature defecated, leaving behind a mound of poop that happened to fossilize—and preserve what an analysis now reveals is the oldest ever evidence of butterflies and moths.

The fossilized piece of poop, known as a coprolite, was found in a 236-million-year-old “communal latrine” at Argentina’s Talampaya National Park, where now-extinct herbivores called dicynodonts engaged in social behavior by effectively creating prehistoric restrooms. While analyzing these coprolites’ contents, researchers found that one of them contained ornate, microscopic scales like the ones on the wings of lepidopterans, the group of insects that contains butterflies and moths.

The discovery helps plug a nagging hole in the evolutionary story of lepidopterans. Family trees based on genetic data had suggested that lepidopterans arose around 241 million years ago. But until the Argentine coprolite scales, the oldest known lepidopteran fossils—wing scales found in sediments in Germany—were only 201 million years old.

The find also implies that butterflies and moths with probosces, those straw-like structures perfect for slurping up nectar, likely evolved between 260 and 244 million years ago. Early probosces may have given early lepidopterans an edge in eating conifers’ sugary secretions—while also setting them up to co-evolve with flowers, which wouldn’t appear for another 100 million years.

In addition, the coprolite’s butterfly scales are so unlike any others found previously that paleontologists have used them to name a new butterfly species: Ampatiri eloisae.

The name honors Eloísa Argañaraz, a doctoral student who died from brain cancer months after co-discovering the coprolites.

It also pays tribute to the Calchaquí Indigenous peoples, who live in the area where the fossil dung was found. In the Calchaquí language, Kakán, ámpa means butterfly, and tiri means ancient. In their worldview, when a warrior dies, their soul becomes a butterfly or journeys on its wings."

From the highlights and abstract:

"Highlights

• After end-Permian mass extinction, the Triassic witnessed a super-radiation of modern insects (i.e., hymenopterans, dipterans, and lepidopterans).

• We report the oldest known record of hexapod scales, which were recovered from a megaherbivore dicynodont coprolite.

• The coprolite comes from a communal latrine in lower Carnian deposits (∼236 Ma) of the Chañares Formation, NW Argentina.

• The unique combination of features (e.g., ornamented hollow scales with internal lumen) suggests lepidopteran affinities.

• The Chañares scales contribute to the temporal mismatch between phylogenomic and fossil evidence of lepidopterans.

Abstract

Life on Earth nearly came to an end during the end-Permian mass extinction (EPME; c. 252 Ma). In its aftermath, the Triassic witnessed the adaptation of survivors to a postapocalyptic world and the establishment of modern ecosystems. Inland, these changes included an outstanding turnover between amniote groups triggered by the diversification of plants and arthropods. A super-radiation of morphologically modern insects occurred in the Triassic, including some of their most successful and ecologically relevant groups, such as Diptera (flies and mosquitoes) and Lepidoptera (moths and butterflies).

Here, we describe the oldest evidence of hexapod scales, preserved within a megaherbivorous kannemeyeriiform dicynodont coprolite. This specimen comes from a communal latrine in the lower Carnian deposits (∼236 Ma) of the Chañares Formation, La Rioja Province, northwestern Argentina. The tiny fossil scales are hollow and ornamented, which is a synapomorphy of Lepidoptera and suggests that they could belong to this group. If this is the case, the Chañares scales would partially fill the temporal mismatch between phylogenomic date and the fossil evidence of butterflies and moths because they preceded the previously oldest lepidopteran record by c. 35 million years.

Moreover, the scales have a combination of features present in early diverging glossatan lepidopterans. The inclusion of the temporal data provided by the Chañares scales into an updated temporal calibration of lepidopteran phylogeny shows that the proboscis, a key evolutionary novelty for the group (Glossata), evolved between c. 260–244 Ma. Thus, the proboscis-bearing lepidopterans would be part of the repertory of new plants and animals that diversified during the aftermath of the EPME."

ScienceAdviser

Ancient poop yields world’s oldest butterfly fossils "Tiny wing scales suggest the proboscis evolved 100 million years before flowers"

Back to the poop: the oldest hexapod scales discovered within a Triassic coprolite from Argentina (no public access)

Graphical abstract

Preserved in a 236-million-year-old piece of fossilized dung, these microscopic wing scales—each less than 200 microns long—are distinctive enough that paleontologists used them to name a species of extinct butterfly, Ampatiri eloisae.

Ancient unicellular organism indicates embryonic development might have existed prior to animals' evolution

Amazing stuff! What was first, the egg or the chicken? Or did evolution develop the same thing twice independently?

"Chromosphaera perkinsii is a single-celled species discovered in 2017 in marine sediments around Hawaii. The first signs of its presence on Earth have been dated at over a billion years, well before the appearance of the first animals. ...

this species forms multicellular structures that bear striking similarities to animal embryos. These observations suggest that the genetic programs responsible for embryonic development were already present before the emergence of animal life, or that C. perkinsii evolved independently to develop similar processes. ...

By observing C. perkinsii, the scientists discovered that these cells, once they have reached their maximum size, divide without growing any further, forming multicellular colonies resembling the early stages of animal embryonic development. Unprecedentedly, these colonies persist for around a third of their life cycle and comprise at least two distinct cell types, a surprising phenomenon for this type of organism. ..."

From the abstract:

"All animals develop from a single-celled zygote into a complex multicellular organism through a series of precisely orchestrated processes. Despite the remarkable conservation of early embryogenesis across animals, the evolutionary origins of how and when this process first emerged remain elusive. Here, by combining time-resolved imaging and transcriptomic profiling, we show that single cells of the ichthyosporean Chromosphaera perkinsii—a close relative that diverged from animals about 1 billion years ago—undergo symmetry breaking and develop through cleavage divisions to produce a prolonged multicellular colony with distinct co-existing cell types. Our findings about the autonomous and palintomic developmental program of C. perkinsii hint that such multicellular development either is much older than previously thought or evolved convergently in ichthyosporeans."

Ancient unicellular organism indicates embryonic development might have existed prior to animals' evolution

The egg or the chicken? An ancient unicellular says egg! "A cell division resembling that of an animal embryo has been observed in a prehistoric unicellular organism, suggesting that embryonic development might have existed prior to the evolution of animals."

A multicellular developmental program in a close animal relative (no public access)

A cell of the ichthyosporean C. perkinsii showing distinct signs of polarity, with clear cortical localization of the nucleus before the first cleavage. Microtubules are shown in magenta, DNA in blue, and the nuclear envelope in yellow.

When India Was An Island

Very recommendable!

How did dinosaur collagen survive for millions of years

Amazing stuff!

"Collagen, a protein found in bones and connective tissue, has been found in dinosaur fossils as old as 195 million years. That far exceeds the normal half-life of the peptide bonds that hold proteins together, which is about 500 years.

A new study ... offers an explanation for how collagen can survive for so much longer than expected. The research team found that a special atomic-level interaction defends collagen from attack by water molecules. This barricade prevents water from breaking the peptide bonds through a process called hydrolysis. ...

In the past decade, paleobiologists have found evidence of collagen preserved in dinosaur fossils, including an 80-million-year-old Tyrannosaurus rex fossil, and a sauropodomorph fossil that is nearly 200 million years old. ...

the peptide bonds that hold collagen together are so resistant to being broken down by water ...

Peptide bonds are formed between a carbon atom from one amino acid and a nitrogen atom of the adjacent amino acid. The carbon atom also forms a double bond with an oxygen atom, forming a molecular structure called a carbonyl group. This carbonyl oxygen has a pair of electrons that don’t form bonds with any other atoms. Those electrons, the researchers found, can be shared with the carbonyl group of a neighboring peptide bond.

Because this pair of electrons is being inserted into those peptide bonds, water molecules can’t also get into the structure to disrupt the bond. ..."

From the abstract:

"Proteins have evolved to function in an aqueous environment. Collagen, which provides the bodily scaffold for animals, has a special need to retain its integrity. This need was addressed early on, as intact collagen has been detected in dinosaur fossils, even though peptide bonds have a half-life of only ∼500 years in a neutral aqueous solution. We sought to discover the physicochemical basis for this remarkable resistance to hydrolysis. Using experimental and computational methods, we found that a main-chain acyl group can be protected from hydrolysis by an O···C═O n→π* interaction with a neighboring acyl group. These interactions engage virtually every peptide bond in a collagen triple helix. This protection, which arises from the Pauli exclusion principle, could underlie the preservation of ancient collagen."

MIT chemists explain why dinosaur collagen may have survived for millions of years | MIT News | Massachusetts Institute of Technology "The researchers identified an atomic-level interaction that prevents peptide bonds from being broken down by water."

How collagen survives for millions of years finally explained

Pauli Exclusion by n→π* Interactions: Implications for Paleobiology (open access)

Graphical abstract

Scheme 1. Assay to Detect Pauli Exclusion by an n→π* Interaction