Genetic structure of yellow cedar (<i>Chamaecyparis nootkatensis</i>)
Bibliographic record
Abstract
A range-wide survey of isozyme variation in yellow cedar (Chamaecyparis nootkatensis (D. Don) Spach; or Alaska cedar) found significant inbreeding and a striking geographical structure. The proportion of diversity among populations (GST) was 0.139, and three major geographical groups were evident: (1) Vancouver Island - mid-north coast British Columbia (B.C.); (2) south coast B.C. - Washington state; (3) southeast Alaska. This may indicate the presence of multiple refugia during ice-age range contractions. Geographically disjunct populations in Oregon and southeastern B.C. were also genetically distinct. Adult inbreeding coefficients (F) were usually positive but varied widely among populations, as did gene diversity. The overall average of F = 0.18 suggests that considerable selfing (ca. 30%) occurs in this species. Other statistics were more typical for a conifer: within population heterozygosity (HS) averaged 0.148, total gene diversity (HT) was 0.171, and the number of alleles per locus and percentage polymorphic loci averaged 1.68 and 50, respectively. This geographic structure has implications for species conservation and for breeding programs. Also, previous studies of other Cupressoideae (Rich. ex Sweet) species indicate that these levels of inbreeding and population structure are not uncommon, and may influence evolutionary divergence in the Cupressoideae.Key words: Chamaecyparis nootkatensis, yellow cedar, genetic structure, inbreeding, phylogeography, isozymes.
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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 | 0.000 |
| 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) | 0.001 | 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".