Epigenetic chromatin modifications in<i>Brassica</i>genomes
Bibliographic record
Abstract
Epigenetic modifications such as histone and DNA methylation are highly conserved among eukaryotes, although the nuclear patterns of these modifications vary between different species. Brassica species represent a very attractive model for analysis of epigenetic changes because of their differences in genome size, ploidy level, and the organization of heterochromatin blocks. Brassica rapa and B. oleracea are diploid species, and B. napus is an allotetraploid species that arose from the hybridization of these two diploids. We found that patterns of DNA and histone H3 methylation differ between Brassica species. The most prominent differences concern the two diploids. DNA methylation was present exclusively in the heterochromatin only in B. rapa. In B. oleracea and B. napus this modification was detected in both euchromatin and heterochromatin. A similar pattern was observed for dimethylation of lysine 9. Dimethylation of lysine 4 is a typical marker of euchromatin in Brassica species, like it is in other plant species. We conclude that the diploid species differ in patterns of analyzed epigenetic modifications and the allotetraploid B. napus has combined patterns from both diploids. Differences in patterns of DNA and histone H3 methylation between Brassica species can be attributed mainly to the genome structure and heterochromatin localization rather than ploidy level.
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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 | 0.000 |
| 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".