Genetic variation in natural populations of <i>Hordeum brevisubulatum</i> native to the Songnen Prairie in northeastern China: Comparison of four nuclear DNA markers
Bibliographic record
Abstract
Hordeum brevisubulatum (Trin) Link, a perennial wild grass, shows high tolerance to salinity- and/or alkaline-eroded soil, and is an important forage grass. Nonetheless, the genetic variation within and among natural populations of this species has not been investigated. In this study, four PCR-based dominant nuclear DNA markers, i.e., amplified fragment length polymorphism (AFLP), inter-simple sequence repeat (ISSR), retrotransposon-microsatellite-amplifiedpolymorphism (REMAP), and random amplified polymor phic DNA (RAPD) were used to investigate the genetic variation of a total of 80 plants with an average of 20 individual plants randomly collected from each of the four natural populations of H. brevisubulatum distributed in the Songnen Prairie in northeastern China. Results indicated that all four markers detected a surprisingly high level of genetic variation among the individual genotypes both within and among populations. Specifically, (i) of the 708 bands produced by 10 AFLP primer pairs, 223 (32%) were polymorphic, corresponding to a genetic similarity coefficient (Dice) range of 0.703 to 0.895 with a mean of 0.793; (ii) of the 174 bands produced by 12 ISSR primers, 149 (85%) were polymorphic, corresponding to a genetic similarity coefficient range of 0.524 to 0.826 with a mean of 0.676; (iii) of the 104 bands produced by REMAP (one retrotransopon-specific primer in combination with each of 8 ISSR primers), 89 (85%) were polymorphic, leading to an average similarity coefficient range of 0.494–0.840 with a mean of 0.688, and; (iv) of the 150 bands produced by 17 RAPD primers, 117 (77%) were polymorphic, giving a similarity coefficient range of 0.526–0.909 with a mean of 0.713. Thus, all four markers are highly informative in detecting genetic variations among the individual genotypes in natural populations of H. brevisubulatum. Nevertheless, no correlation was detected among the markers, suggesting that they likely targeted to different genomic regions of H. brevisubulatum. Whereas ISSR, REMAP and RAPD showed significantly higher levels of polymorphism than AFLP, only the latter was capable of grouping some of the plants largely in accordance with their geographic localities, suggesting population differentiation probably occurred preferentially at genomic regions targeted to by AFLP primers. Key words: Genetic diversity, Hordeum brevisubulatum, Molecular markers, Population differentiation
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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) | 0.000 | 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".