Evolution of Mitochondrial DNA Variation within and among Yukon River Chum Salmon Populations
Bibliographic record
Abstract
Abstract We surveyed seven regions of the mitochondrial DNA (mtDNA) genome for restriction site variation to investigate the evolution of genetic variability in chum salmon Oncorhynchus keta from the Yukon River. Chum salmon from other Alaska regions were also analyzed to provide context for mtDNA variation. No divergence was observed in mtDNA haplotype frequency distributions among Yukon River populations, but divergence was observed across Alaska. The haplotype genealogy identified two lineages, and nested clade analysis revealed significant relationships between the geographical distribution of haplotypes and their genealogy for a two‐step clade (which predominates in the Yukon River), a three‐step clade, and for the total cladogram. The demographic signal detected for the two‐step clade was consistent with isolation by distance, whereas contiguous range expansion was identified for the three‐step clade and the total cladogram. The absence of signals of historical fragmentation suggests that incomplete lineage sorting is responsible for paraphyly within the Yukon River. Mismatch analysis reveals either that an ancestral Yukon River population underwent a post‐Pleistocene expansion followed by subdivision or that expansion and subdivision coincided. Although restriction site analysis of mtDNA is of limited use for Yukon River chum salmon fishery management applications (e.g., mixed‐stock analysis), it is useful for separating population history from contemporary processes and aids our understanding of Yukon River chum salmon evolution.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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".