Turning Red to Green Repeatedly: Ancestral LWS Duplications Drive Convergent Visual Tuning in Teleost Fishes.
8 affiliations
- 1The School of the Environment, The University of Queensland, Brisbane, QLD 4072, Australia
- 2Department of Biology, University of Maryland, College Park, MD 20742, USA
- 3Laboratorio de Ecología Acuática, Instituto BIÓSFERA, Universidad San Francisco de Quito, Quito 170150, Ecuador
- 4Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 12844 Prague, Czech Republic
- 5Condensed Matter Theory Group, PSI Center for Scientific Computing, Theory, and Data, 5232 Villigen-PSI, Switzerland
- 6Department of Biology, ETH Zürich, Zürich, Switzerland
- 7Laboratory of Biomolecular Research, PSI Center for Life Sciences, 5232 Villigen-PSI, Switzerland
- 8Swiss Institute of Bioinformatics (SIB), 1015 Lausanne, Switzerland
Abstract
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.
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BibTeX
@article{cortesi2026turning,
title = {{Turning Red to Green Repeatedly: Ancestral LWS Duplications Drive Convergent Visual Tuning in Teleost Fishes.}},
author = {Fabio Cortesi and Daniel Escobar‐Camacho and G. Sommer and Martin Luehrmann and Flurin Hidber and Xavier Deupí and Karen L. Carleton and Zuzana Musilová},
journal = {Molecular ecology},
year = {2026},
month = oct,
doi = {10.1111/mec.70592},
url = {https://europepmc.org/article/MED/42897799},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Turning Red to Green Repeatedly: Ancestral LWS Duplications Drive Convergent Visual Tuning in Teleost Fishes.
AU - Fabio Cortesi
AU - Daniel Escobar‐Camacho
AU - G. Sommer
AU - Martin Luehrmann
AU - Flurin Hidber
AU - Xavier Deupí
AU - Karen L. Carleton
AU - Zuzana Musilová
PY - 2026
DA - 2026/10/01
JO - Molecular ecology
DO - 10.1111/mec.70592
UR - https://europepmc.org/article/MED/42897799
AB - 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.
SN - 0962-1083
SN - 1365-294X
ER -