The 5S DNA sequences in Hordeum bogdanii and in the H. brevisubulatum complex, and the evolution and the geographic dispersal of the diploid<i>Hordeum</i>species (Triticeae: Poaceae)
Bibliographic record
Abstract
The molecular diversity of 5S rDNA from the closely related Asiatic diploid species, Hordeum bogdanii and the H. brevisubulatum complex has been catalogued and analysed. As in previous studies in Hordeum, we found that the sequences are constrained in such an manner that unit classes can be defined. The long H1 unit class, known to occur in all Eurasian species, was frequently found in these 2 taxa. In addition, we identified a new unit class, called the short H3 to reflect the H genome found in these 2 taxa. Although the 2 taxa are very close morphologically, the variation in the long H1 DNA units is constrained to such a great degree that, in many cases, the accessions in a unit class from a single species are clustered. In H. bogdanii, the majority of the sequences are grouped in this manner, whereas in the H. brevisubulatum complex, the tendency to be constrained is lower in some but not all subspecies. These results support keeping H. brevisubulatum ssp. violaceum and ssp. iranicum as 1 species with the long H1 and short H1 unit classes, while retaining ssp. nevskianum and ssp. turkestanicum in the H. brevisubulatum complex. We have summarized our work on the presence/absence of the 10 unit classes found in all diploid species of Hordeum. A phylogenetic analysis, based strictly on the presence/absence of unit classes, indicated clearly that all the South American diploids and all the North American diploids possess long H2 and long Y2 unit classes and, except for H. californicum and H. pusillum, which contain long H1 in addition to the long H2 and long Y2 classes, are devoid of the long H1 unit class. This suggests that the gene gain/loss process from a common ancestor has been concomitant with intercontinental dispersal between the Old and the New Worlds.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 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) | 0.001 | 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".