A modified method of shell windowing for producing somatic or germline chimeras in fertilized chicken eggs
Bibliographic record
Abstract
Stage X chick blastoderms following oviposition were accessed via a small window in the egg. Windowing, however, substantially reduces the hatchability of eggs containing early embryos. For example, only 32 of 389 (8.2%) eggs hatched after standard windowing with or without irradiation or injection. Ex ovo culture systems can overcome this problem but are labor intensive. A modification of a standard windowing technique has yielded an average hatch rate of 32% for 892 windowed eggs independent of incubator type, gamma-irradiation, or injection of the embryo. This was a fourfold increase over a standard windowing method. Similar hatch rates were observed using fertile eggs from five chicken lines [Barred Plymouth Rock (BR), Athens-Canadian (AC), Line 0, SPAFAS, and commercial White Leghorns (WL)]. The modification involves covering the egg shell membrane with PBS after grinding away the shell and before piercing the membrane. The window is then sealed by overlaying with fresh shell membrane and cementing it in place once it has dried. The method has been used successfully for the production of somatic and germline chimeras because donor BR blastodermal cells injected into Stage X, gamma-irradiated recipient embryos from WL or AC yielded a hatch of 33.7%, of which 42.3% were feather chimeras. Two of 11 cockerels tested were germline mosaics bearing at least 1% BR sperm. The modified windowing technique may be broadly applicable in emerging technologies in avian transgenesis and development.
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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 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".