Chloroplast DNA polymorphisms in eastern hemlock: range-wide genogeographic analyses and implications for gene conservation
Bibliographic record
Abstract
The objective of this study was to determine if the genetic diversity of eastern hemlock ( Tsuga canadensis (L.) Carrière) is uniformly distributed or structured. Such information is relevant to help guide conservation efforts. Individuals were sampled in 60 range-wide populations of T. canadensis and genotyped at seven polymorphic chloroplast DNA loci. All 16 chlorotypes identified in T. canadensis were highly divergent from the unique chlorotype detected in Carolina hemlock ( Tsuga caroliniana Engelm.). Among-population differentiation in T. canadensis was low (GST = 0.020) and the distribution of chlorotypes did not show any strong geographical pattern, which is likely due to the homogenizing effect of pollen gene flow during the Holocene. Nevertheless, a spatial Bayesian approach revealed two distinct groups of populations. Furthermore, an analysis of relative genetic distances indicated that southeastern Appalachian populations harboured greater population differentiation while conserving relatively high allelic richness, which might represent the imprint of an ancient glacial refugium in the region. Thus, these distinctive genetic patterns and the risk of Tsuga decline following climate warming combined with the introduction of the insect Adelges tsugae (Annand) indicate that the southern part of the range should be considered of high priority for ex situ conservation.
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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 | 0.001 | 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) | 0.000 | 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".