Patterns of Nucleotide Diversity of the <i>ldpA</i> Circadian Gene in Closely Related Species of Cyanobacteria from Extreme Cold Deserts
Bibliographic record
Abstract
In the circadian system of cyanobacteria, the ldpA gene is a component of the input to the clock. We comparatively analyzed nucleotide polymorphism of this gene in populations of two closely related species of cyanobacteria (denoted as Synechococcus species S1 and S2, respectively) from extreme cold deserts in Antarctica, the Canadian Arctic, and Tibet. Although both species manifested similarly high haplotype diversities (0.990 and 0.809, respectively), the nucleotide diversity differed significantly (0.0091 in S1 and 0.0037 in S2). The populations of species S2 were more differentiated (F(ST) = 0.2242) compared to those of species S1 (F(ST) between 0.0296 and 0.1188). An analysis of positive selection with several tests yielded highly significant values (P < 0.01) for both species. On the other hand, these results may be somewhat compromised by fluctuating population sizes of the species. The apparent selection pressure coupled with the pronounced demographic factors, such as population expansion, small effective population size, and genetic drift, may thus result in the observed significant interpopulation differentiation and subsequent speciation of cyanobacteria.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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".