The bryophyte <i>Physcomitrella patens</i> replicates extrachromosomal transgenic elements
Bibliographic record
Abstract
Physcomitrella patens, recently renamed Aphanoregma patens, has been transformed with the plasmid, pBI426. On selective medium approx. 30% of regenerants expressed the transformed phenotype transiently (transients). The remaining 70% (transformants) retained their transformed phenotype (GUS‐positive and resistant to G418) indefinitely when subcultured repeatedly on selective medium. However, most lost this phenotype after one or two passages through nonselective medium (unstable transformants). Approximately 0.2% of transformants retained their transformed phenotype after numerous passages through nonselective medium (stable transformants). Using PCR methodology, it has been shown that loss of the transformed phenotype by unstable transformants is invariably accompanied by disappearance of the transgenic DNA. Southern blot analysis data argue strongly that unstable transformants cultured under selective conditions contain unintegrated pBI426 as circular concatenates consisting of 3–40 copies of the plasmid. Under selective conditions, it appears that replication and/or partitioning of these extrachromosomal concatemers might be growth rate‐limiting. This is the first report of a transgenic, autonomously replicating extrachromosomal element in a photosynthetic plant. A single copy of pBI426 has been inserted into the moss genome in each of three stable transformants analysed.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".