Physical localization and genetic mapping of the fertility restoration gene<i>Rfo</i>in canola (<i>Brassica napus</i>L.)
Bibliographic record
Abstract
The Ogu cytoplasm for male sterility and its fertility restorer gene Rfo in canola (Brassica napus L.) were originally introgressed from radish (Raphanus sativus L.) and have been widely used for canola hybrid production and breeding. The objective of this study was to determine the physical location of the Rfo locus in the canola genome using fluorescence in situ hybridization and genetic mapping. For physical localization of the Rfo gene, two bacterial artificial chromosome (BAC) clones, G62 and B420, which were closely linked to the Rfo gene, were used as probes to hybridize with the somatic metaphase chromosomes of a canola hybrid variety, PHI-46 (46H02), containing the Rfo fragment. The results showed that both clones were physically located at the end of one large metacentric chromosome. By simultaneous use of two BAC clones and 45S rDNA repeated sequences as the probes, we demonstrated that the large metacentric chromosome probed with the two BAC clones did not carry 45S rDNA repeated sequences. The chromosome was 3.65 +/- 0.74 microm in average length (20 cells) and ranked second in size among the chromosomes without 45S rDNAs. The centromere index of the chromosome (20 cells) was calculated as 43.74 +/- 4.19. A comparison with previously reported putative karyotypes of B. napus (AACC) and its diploid ancestors Brassica rapa L. (AA) and Brassica oleracea L. (CC) suggests that the chromosome carrying the Rfo fragment might belong to one of three large metacentric chromosomes of the C genome. Genetic mapping has confirmed the localization of the Rfo fragment to the distal region of linkage group N19, which corresponds to the C genome in B. napus. This study has provided the evidence of the location of the Rfo gene on canola chromosomes and established a basic framework for further physical mapping and manipulation of the gene.
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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 | 0.000 | 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) | 0.001 | 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".