Chloroplast DNA phylogeography of<i>Rhodiola alsia</i>(Crassulaceae) in the Qinghai–Tibet Plateau
Bibliographic record
Abstract
We studied the phylogeography of Rhodiola alsia (Fröderström) S.H. Fu, which is a perennial herbaceous plant endemic to the Qinghai–Tibet (Q–T) Plateau, by sequencing one intergenic chloroplast spacer, rpl20–rps12 (844 bp). The sampling design included 18 populations and 315 individuals, and spanned the entire distribution range of the species. Thirty-one haplotypes were characterized, and polymorphism was observed both within and among populations. Most haplotypes were restricted to single sites or to neighbouring populations, suggesting an extremely low level of long distance gene flow via seeds. Only three haplotypes were common and widespread throughout the distributional range of R. alsia. The present geographical distribution of haplotypes probably reflects an ancient geographical pattern between the platform and southeastern margin of the Q–T Plateau identified as genetic hotspot areas. We suggest that populations of R. alsia survived in isolated refugia located in the platform and the southeastern margin of the Q–T Plateau during the Quaternary glaciation, at least during the last glaciation maximum (LGM, 32 000–16 000 years ago). The populations of R. alsia were geographically isolated by a subsequent local range expansion and independent evolution. The genetic structure of R. alsia is very different from previous phylogeographical studies of Q–T Plateau alpine plants and illustrates the importance of species-specific characteristics such as distribution areas and life-history traits which are mainly responsible for different patterns of genetic variation. Our investigation thus provides a new pattern of several refugia on the plateau platform.
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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) | 0.001 | 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".