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Turning Red to Green Repeatedly: Ancestral LWS Duplications Drive Convergent Visual Tuning in Teleost Fishes
Item type: Journal Article
Cortesi F.; Escobar-Camacho D.; Sommer G.M.; et al. (2026)
Photopigments, formed by an opsin protein bound to a light-sensitive chromophore, underlie vertebrate vision. Long-wavelength–sensitive (LWS) opsins mediate red-light detection, and most teleosts retain a single functional LWS1. A shorter-shifted green-sensitive paralog (LWS2) is found only in a few lineages. By mining teleost genomes and sequencing retinal transcriptomes, we identify elopomorphs as an additional lineage retaining LWS2 (alongside characins and osteoglossomorphs). Surprisingly, we reveal a previously overlooked, shorter-shifted paralog, LWS3, restricted to gobies (Percomorpha) and arising from an ancestral duplication either in the teleost or in the percomorph ancestor. Structural modelling of twelve LWS opsins reveals convergent evolution at four key amino acid sites (214, 259, 261, 269) in the retinal-binding pocket, indicating convergent substitutions in human MWS (an old-world primate-specific duplicate of the vertebrate LWS1), teleost LWS2, and goby LWS3 relative to red-sensitive counterparts, consistent with repeated spectral shifts towards greener wavelengths. In several lineages, including characins, mormyrids, gobies, and primates, these shorter-shifted LWS opsins have at least partially replaced the canonical green-sensitive RH2-based visual pigment. Retinal transcriptomes revealed variable lws3 expression across adult gobies, either complementing lws1 in most species, or dominating the visual opsin expression profile as in the sicydiines. In situ hybridisation in the whitebarred goby (Amblygobius phalaena; Valenciennes, 1837) showed that lws1 and lws3 are expressed in separate double-cone members, analogous to rh2 expression in other fish species. Together, these results show that repeated convergence towards shorter LWS sensitivity in vertebrate evolution involves coordinated changes at the molecular, regulatory, and functional levels, providing a striking example of multilevel sensory adaptation.
Preference for evolving dark energy in light of the galaxy bispectrum
Item type: Journal Article
Lu Z.; Simon T.; Zhang P. (2026)
We analyse pre-DESI clustering data using a dark energy equation of state w(z) parametrised by (w0, wa), finding a 2.8-3.9σ preference for evolving dark energy over the cosmological constant Λ when combined with cosmic microwave background data from Planck and supernova data from Pantheon+, Union3, or DESY5. Our constraints, consistent with DESI Y1 results, are derived from the power spectrum and bispectrum of SDSS/BOSS galaxies using the Effective Field Theory of Large Scale Structure (EFTofLSS) at one loop. The evidence, estimated as the Gaussian-equivalent significance from the Δχ2-statistics to (w0, wa) = (-1, 0) for two degrees of freedom, remains robust across analysis variations but disappears without the one-loop bispectrum. When combining DESI baryon acoustic oscillations with BOSS full-shape data, while marginalising over the sound horizon in the latter to partially mitigate potential correlations, the significance increases to 3.7-4.4σ, depending on the supernova dataset. Using instead a data-driven reconstruction of w(z), we show that deviations from Λ can be observed at multiple redshifts, though at a low level of significance: only when imposing the specific parametrisation implied by (w0, wa) the above evidence emerges. In addition, our findings are interpreted within the Effective Field Theory of Dark Energy (EFTofDE), from which we explicitly track the non-standard time evolution in EFTofLSS predictions. For perturbatively stable theories in the w < -1 regime, the preference for w0 waCDM persists notably in the clustering limit (cs2 → 0) when higher-derivative corrections are present.
When environments mismatch—the limits of transgenerational climate memory in Scots pine
Item type: Journal Article
Luo N.; Gessler A.; Noé F.; et al. (2026)
A long-term irrigation experiment in the dry Rhône Valley of Switzerland provides a unique opportunity to examine transgenerational environmental memory effects of persistent drought and irrigation in Scots pine (Pinus sylvestris L.). Previous work in this system showed that offspring from mother trees exposed to chronic drought (non-irrigated control) versus long-term irrigation differed markedly in growth and survival. Offspring from irrigated mothers grew faster under irrigated conditions but performed poorly under drought, whereas offspring from drought-exposed mothers showed higher growth and survival under drought conditions. While these responses suggested transgenerational environmental memory, the relative contributions of maternal provisioning versus epigenetic mechanisms could not be fully resolved. Notably, mother trees did not differ in genotype, and seed mass did not vary between treatments, indicating a limited role of maternal effects. Here, we tested whether transgenerational environmental memory effects persist after offspring were grown for 3 years under non-experimental conditions before being re-exposed to experimental hot-drought and irrigation treatments. In contrast to the earlier study, offspring from irrigated mothers did not show higher growth performance under irrigated conditions, indicating that irrigation-related memory weakened during the intervening non-treated phase. Conversely, seedlings originating from drought-exposed mothers consistently exhibited higher carbon assimilation and stem growth than those from irrigated mothers, irrespective of experimental treatment. Gene expression analyses showed differences in the number and identity of differentially expressed genes between offspring of drought- and irrigation-exposed mothers, although we lack data on DNA methylation, histone modifications or small RNAs. Patterns in primary metabolites broadly mirrored the results of gene expression, with modest differences in osmoprotectants and stress-related compounds. Overall, our results indicate that transgenerational environmental memory effects in P. sylvestris can diminish over time and, depending on the parental and offspring environments, may even result in mismatch and maladjustments.
Model-building implications from light magnetic monopoles: a case study of flavour deconstruction
Item type: Journal Article
Pesut M.; Racco D.; Zhao Y. (2026)
We highlight a generic connection between extensions of the Standard Model featuring low-scale semi-simple embeddings of U(1)EM and the phenomenology of light magnetic monopoles in the early Universe. Combining cosmological, astrophysical, and direct-search constraints, we show that magnetic monopoles with masses far below the scale of Grand Unified Theories are generically excluded and require low-scale inflation to dilute their abundance, followed by reheating below the monopole-production scale. These constraints are particularly relevant for flavour non-universal models, which provide a well-motivated framework to address the hierarchical structure of Yukawa couplings while allowing new dynamics close to the TeV scale compatible with experimental bounds. In many of these constructions, the sequential breaking of semi-simple gauge groups through intermediate stages containing a U(1) factor generically leads to the production of light magnetic monopoles. We show that the parameter region naturally predicted by these models implies low-scale inflation, with reheating temperature as low as 103–104 TeV. These results significantly reduce the otherwise large allowed inflationary window and establish a direct connection between flavour physics and the thermal history of the early Universe: future evidence for a low-scale semi-simple embedding of U(1)EM, in particular through flavour non-universal interactions, would point towards low-scale reheating, while probes of primordial gravitational waves could directly constrain the scale at which low-scale semi-simple groups can appear.
Ultrabroadband Gain-Switched and Superluminescent Terahertz Semiconductor Lasers
Item type: Journal Article
Senica U.; Schreiber M.A.; Beck M.; et al. (2026)
Terahertz quantum cascade lasers (THz QCLs) are chip-scale semiconductor lasers operating in the frequency range between 1 and 6 THz, useful as compact sources for spectroscopy, communications, and nondestructive imaging and testing. Here, we apply low-frequency microwave modulation on a planarized THz QCL to generate ultrabroadband emission in the THz range. For very low modulation frequencies below 1 GHz, a gain-switched octave-spanning spectrum with a smooth spectral envelope is generated between 1.9 and 4.1 THz. Increasing the modulation frequency broadens the lasing modes until a low-coherence, continuous emission spectrum is achieved in the superluminescent regime, covering the spectral region between around 3 and 4 THz, without any discrete lasing modes or spectral gaps. We complement the experimental results with extensive analytical models and numerical simulations that capture the intracavity laser dynamics and fully explain the different operation regimes. These devices could prove useful for absorption spectroscopy without any spectral gaps, and as ultrabroadband sources of THz radiation.