Single cones give rise to multi-cone types in the retinas of fishes
Bibliographic record
Abstract
Retinal cone photoreceptors are specialized neurons that capture light to begin the process of daylight vision. They occur as individual cells (i.e., single cones), or as combinations of structurally linked cells, such as the double and triple cones found in the retinas of non-eutherian vertebrates. These different morphological cone types form mosaics of varying regularity, with single and double cones patterned as nearly perfect lattices in the retinas of many bony fishes (teleosts) and some geckos. Although double cones were first reported over 150 years ago, how they form (i.e., whether from coalescing single cones, or from structurally linked cone progenitors) remains uncertain. In turn, whether there is a general vertebrate sequence in appearance of morphological cone types and mosaics is unknown. Here, the developing retinas of seven species of teleosts were examined revealing that only single cones, arranged in hexagonal-like mosaics, were present at the earliest stages of photoreceptor differentiation. Double cones arose from coalescing single cones and the formation of multi-cone type mosaics (such as the square mosaic, where each single cone is surrounded by four double cones) followed different dynamics depending on whether the species was altricial or precocial. Single cones were therefore the primordial cells from which all multi-cone types arose and hexagonal-like mosaics preceded other mosaic patterns. Based on observations from transitional retinas, we propose a model for mosaic transformation from hexagonal to square. The double cones of fishes and those of land vertebrates constitute an example of convergent evolution to achieve the elliptical waveguide structure, likely for improved spatio-temporal resolution.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".