An artifact of recombinatorial cloning challenges established beliefs of plasmid cotransformation, selection, and maintenance
Bibliographic record
Abstract
Gateway cloning is an easy, efficient, accurate, and versatile cloning strategy. During Expression clone validation, we sometimes see an additional band co-migrating with the pDONR (Entry) backbone. We show that this “mystery” band is not an artifact of aberrant recombination but instead originates from a cotransformation event, where more than one different plasmid is transformed into a single Escherichia coli cell simultaneously and in the absence of antibiotic selection. We find that the unselected pDONR Entry plasmid is cotransformed into E. coli with the desired Expression vector in 9%–29% of colonies and is maintained without antibiotic selection, despite plasmid incompatibility. We propose an easy strategy to screen for and eliminate cotransformants. Our results challenge accepted beliefs of bacterial plasmid transformation, selection, and maintenance and comprise the first documented occurrence of cotransformation in Gateway cloning.
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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 | 0.019 | 0.031 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.007 |
| Scholarly communication | 0.004 | 0.004 |
| Open science | 0.002 | 0.004 |
| Research integrity | 0.002 | 0.006 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
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".