A comparative study of rhodopsin function in the great bowerbird (<scp><i>P</i></scp><i>tilonorhynchus nuchalis</i>): Spectral tuning and light‐activated kinetics
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Rhodopsin is the visual pigment responsible for initiating the phototransduction cascade in vertebrate rod photoreceptors. Although well-characterized in a few model systems, comparative studies of rhodopsin function, particularly for nonmammalian vertebrates are comparatively lacking. Bowerbirds are rare among passerines in possessing a key substitution, D83N, at a site that is otherwise highly conserved among G protein-coupled receptors. While this substitution is present in some dim-light adapted vertebrates, often accompanying another unusual substitution, A292S, its functional relevance in birds is uncertain. To investigate functional effects associated with these two substitutions, we use the rhodopsin gene from the great bowerbird (Ptilonorhynchus nuchalis) as a background for site-directed mutagenesis, in vitro expression and functional characterization. We also mutated these sites in two additional rhodopsins that do not naturally possess N83, chicken and bovine, for comparison. Both sites were found to contribute to spectral blue-shifts, but had opposing effects on kinetic rates. Substitutions at site 83 were found to primarily affect the kinetics of light-activated rhodopsin, while substitutions at site 292 had a larger impact on spectral tuning. The contribution of substitutions at site 83 to spectral tuning in particular depended on genetic background, but overall, the effects of substitutions were otherwise surprisingly additive, and the magnitudes of functional shifts were roughly similar across all three genetic backgrounds. By employing a comparative approach with multiple species, our study provides new insight into the joint impact of sites 83 and 292 on rhodopsin structure-function as well as their evolutionary significance for dim-light vision across vertebrates.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it