Continuous UV irradiation played an inconclusive role in selecting the canonical genetic alphabet.

October 13, 2026| Source: Proceedings of the National Academy of Sciences of the United States of America

An abundance of heterocyclic molecules analogous to canonical nucleobases (i.e., adenine, thymine, guanine, cytosine, and uracil) used as the genetic alphabet in DNA and RNA could have been present in various prebiotic environments on early Earth. However, extant biology generally uses the canonical nucleobases and nucleosides as the genetic alphabet, and not any number of possible noncanonical counterparts. Ultraviolet (UV) irradiation was likely abundant on the surface of the early Earth and has been suggested to play a role in the selection of the canonical nucleobases and nucleosides as the genetic alphabet of life. Previous studies examining the photophysics of various canonical and noncanonical nucleobases and nucleosides have suggested that the canonical molecules have shorter excited-state lifetimes and may therefore be less prone to photodamage. Here, we evaluate the photostabilities of various canonical and noncanonical nucleobases and nucleosides under continuous UV irradiation at [Formula: see text] nm to determine their rates of degradation and compare how photostable they are. Additionally, we estimate the relative photostabilities of these molecules under a plausible early Earth UV environment. We find that the canonical nucleobases and nucleosides span nearly the entire range of observed rates of photodegradation. These results indicate that the selective factors for the genetic alphabet may be more complex than purely due to selection by UV photostability.

Read the original source →

Nutrient legacies from elephant megacarcasses create coldspots of biodiversity and hotspots of ecosystem processes.

Terrestrial megafauna (animals >1,000 kg) have substantial impacts on ecosystems while alive; yet, we know little about the impacts of these ecosystem engineers after they die. Like whale carcasses in the ocean, terrestrial megacarcasses may leave ecological legacies via the nutrient pulses they create on the landscape. Here, we investigated the impact of elephant megacarcasses on savanna ecosystems in Kruger National Park, South Africa. To determine how elephant carcasses affect below- and a

EnvironmentOctober 20, 2026

Maternal ranging strategies facilitate offspring social play at energetic cost in the most solitary ape.

In most vertebrates, social play among peers is considered essential for behavioral development. Yet in solitary species bearing single offspring, opportunities for social play are inherently scarce. Whether mothers of such species actively facilitate play opportunities for their offspring, and at what cost, remains unknown. We used 15 y of behavioral and movement data (∼32,600 observation hours) from 31 wild Bornean orangutan ( Pongo pygmaeus wurmbii ) mother-offspring pairs to test whet

EnvironmentOctober 20, 2026

Evolution shapes ecosystem resilience through spatial self-organization.

Drylands are globally widespread and ecologically important but vulnerable to climate change. Many exhibit spatially self-organized vegetation patterns that enhance resilience by enabling vegetation to reorganize their patterns under drying, thereby optimizing water use and maintaining productivity. Plants can also undergo evolution in response to environmental change. Although both spatial self-organization and rapid evolution are fundamental mechanisms of resilience, their interaction remains

EnvironmentOctober 13, 2026

Fault-controlled natural hydrogen reservoirs as underground hydrogen storage sites.

Underground hydrogen storage requires geological formations with demonstrated hydrogen containment, yet no conventional storage candidate (salt caverns, aquifers, or depleted hydrocarbon reservoirs) offers direct, prior evidence of H 2 -specific sealing. We propose that subcommercial natural hydrogen reservoirs, where H 2 has accumulated over geological timescales, can serve as precertified storage sites. This proposition is evaluated using the Bulqizë fault-controlled natural H 2 reservoir

EnvironmentOctober 13, 2026

Breaking trait scaling via the evolution and regulation of dimorphic decoupling in ants.

The evolution of allometry, changing how morphological traits scale to body size, has fueled adaptive radiations. In ants, allometry has facilitated the repeated evolution of a worker-soldier caste system. Here, we reveal an unexpected morphological pattern and its superorganismal regulation within the hyperdiverse genus Pheidole . We uncovered that antennal sizing between the small worker and the big soldier is identical, lacking intercaste scaling (antennae-body scaling is decoupled) yet retai