Imprinting defects in mouse embryos: stochastic errors or polymorphic phenotype?
Bibliographic record
Abstract
Defects in expression of imprinted genes are believed to cause developmental abnormalities and play a role in carcinogenesis. To determine whether spontaneous imprinting defects may occur in mouse embryos, we studied the expression of two imprinted genes H19 and Igf2 in individual postimplantation 7.5 d.p.c. and 8.5 d.p.c. embryos. Biallelic expression of H19 was found in 1.6% of the embryos, whereas biallelic expression of Igf2 was found in 0.5% of the embryos. The loss of H19 imprinting (LOI) observed in a small fraction of early postimplantation embryos may be purely stochastic. Alternatively, since we never observed it in an inbred background, it may depend on genetic factors acting in trans. Either mechanism could explain the occurrence of polymorphic imprinting as well as the genesis of sporadic imprinting defects, including cancer. The frequency of LOI of H19 was higher than the incidence of sporadic imprinting disorders in humans (about 1 in 20,000). This contradiction may be explained by different incidence of imprinting errors in different imprinted regions of the genome, in different species, or by loss of the majority of nonmosaic embryos with imprinting defects before birth.
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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 | 0.000 |
| 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".