<i>Cenchrus purpureus</i> and <i>Cenchrus americanus</i> repeatome provide chromosomal markers to distinguish subgenomes
Bibliographic record
Abstract
Cenchrus L. is an important genus within the family Poaceae, comprising species of agronomic importance, such as Cenchrus purpureus and Cenchrus americanus. Cenchrus americanus is a diploid species (2 n = 2 x = 14, AA genome), while C. purpureus is an allotetraploid (2 n = 4 x = 28, A′A′BB genome). The A′ subgenome is proposed to be homeologous to and possibly derived from the A subgenome, while the origin of the B subgenome remains undefined. Despite their distinct subgenomic compositions, both species exhibit a high level of genome homology. This study aimed to characterize and compare the repetitive genome fraction of C. purpureus and C. americanus using genome skimming and a graph-based clustering approach, as well as in situ hybridization. The repetitive genome fraction of C. purpureus and C. americanus corresponds to 52.23% and 76.82%, respectively. The most abundant repetitive elements in both species are the LTR retrotransposons. Satellite DNA sequences correspond to 2.55% and 4.17% of the species’ genome, respectively. Four new satellite sequences were identified as A, A′, and B subgenome-specific sequences, along with new centromeric variants. The ancestral relationship and the polyploidization–diploidization cycles played a fundamental role in the composition of their repetitive fraction.
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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 | 0.001 |
| 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) | 0.002 | 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".