Parallelism in the oxygen transport system of the lake whitefish: the role of physiological divergence in ecological speciation
Bibliographic record
Abstract
In North America, populations of lake whitefish (Coregonus clupeaformis) have evolved sympatric 'dwarf' and 'normal' ecotypes that are associated with distinct trophic niches within lakes. Trophic specialization should place diverging physiological demands on individuals, and thus, genes and phenotypes associated with energy production represent ideal candidates for studies of adaptation. Here, we test for the parallel divergence of traits involved in oxygen transport in dwarf and normal lake whitefish from Québec, Canada and Maine, USA. We observed significant differences in red blood cell morphology between the ecotypes. Specifically, dwarfs exhibited larger nuclei and a higher nucleus area/total cell area than normal whitefish in all of the lakes examined. In addition, isoelectric focusing gels revealed variation in the haemoglobin protein components found in whitefish. Dwarf and normal whitefish exhibited a similar number of protein components, but the composition of these components differed, with dwarf whitefish bearing a greater proportion of cathodic components compared to the normals. Furthermore, dwarf whitefish showed significant haemoglobin gene upregulation in the brain compared with the levels shown in normals. Together, our results indicate that metabolic traits involved in oxygen transport differ between the whitefish ecotypes and the strong parallel patterns of divergence observed across lakes implicates ecologically driven selection pressures. We discuss the function of these traits in relation to the differing trophic niches occupied by the whitefish and the potential contributions of trait plasticity and genetic divergence to energetic adaptation.
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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 | 0.001 |
| 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 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".