Bibliographic record
Abstract
somatic (diplontic) selection would sufficiently rapidly elim inate heterozygous cell lineages after tissue differentiation has started. An alternative explanation is elimination of one of the genomes, followed by chromosome doubling of the remaining (single) genome, resulting in a homozygous diploid. There are numerous examples of genome separation in hybrids (Sybenga 1992), in which centromere behaviour is species dependent, and in which the centromeres of one species are activated later than those of the other species. The late centromeres fail to reach the metaphase plate simultaneously with the early centromeres, and the central space of the anaphase‐telophase group is occupied by chromosomes of the early species. Only the periphery is then available for the late chromosomes. This is reflected by the position of the chromosomes at interphase or mitosis. In extreme cases the late chromosomes do not reach telophase, and are eliminated. This occurs especially in young embryos where rapid divisions require well synchronized centromere activity. This phenomenon is used for producing haploids of one species from hybrids with another species. Spontaneous chromosome doubling is rare, but when the haploids are artificially doubled, homozygous diploids result. In a number of insects, imprinting of the chromosomes of one parent has a comparable effect: one set of chromosomes is eliminated. This mechanism of elimination of one specific genome can not have operated in the particular case considered here, as homozygosity for markers of both parents is recorded. Random loss of (initially) single chromosomes with equivalent centromeres from diploid hybrid nuclei, first re sulting in genetic instability and consequently in rapid loss of other chromosomes until a balanced haploid set remains, is common in some imperfect fungi (Pontecorvo 1958). The haploid state is the natural somatic state, and a series of un balanced mitoses does not present a threat to the very restricted differentiation. If this would occur in hybrid plants, chromosome number doubling would result in homozygous diploid sectors. However, in plants, the diploid state is the natural state and mitosis is normally very stable when the
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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 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.005 |
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".