Extensive NOR site polymorphism in geographically isolated populations of Golden mahseer,<i>Tor putitora</i>
Bibliographic record
Abstract
Analyses of nucleolar organizer region (NOR) site polymorphism using silver staining were carried out in 72 individuals of 5 geographically isolated populations of Tor putitora from India. All Ag-NORs analyzed were constituted by rDNA that was confirmed by the presence of positive fluorescence in situ hybridization (FISH) signals. Analyses of the extra NORs among the populations confirmed the hypothesis that multi-chromosomal NOR site polymorphism is not an exception but a rule. We found a negative correlation between the mean number of extra NORs and geographical distance from the Alaknanda River population, and a significant positive correlation between the genetic distances obtained by NOR data and geographical distances among the isolated populations. These findings suggest a single geographical origin of this NOR polymorphism, from which it might have radiated to neighboring populations before their isolation. The distribution of NOR site variation was compared with the sequence variation of the ITS1 region of major rDNA (45S) and the two were found to be positively related. Different mechanisms such as transposable elements adjacent to ribosomal genes, repetitive elements which could serve as a point for chromosome exchange, amplification of minor rDNA loci, and reinsertion of extrachromosomal rDNA amplified during oogenesis have been proposed to explain the apparent NOR site polymorphism. The high dispersion of NOR site variants within and among the populations suggests that whatever transposition phenomenon is responsible for repetitive DNA or NOR jumping, it could still be active in T. putitora.
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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 | 0.001 |
| 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) | 0.001 | 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".