The distribution of divergent mitochondrial DNA lineages of threespine stickleback (<i>Gasterosteus aculeatus</i>) in the northeastern Pacific Basin: post‐glacial dispersal and lake accessibility
Bibliographic record
Abstract
Abstract Aim This study furthers the documentation of the geographical distribution of two divergent ( c . 3%) mitochondrial DNA clades in the threespine stickleback ( Gasterosteus aculeatus ) and tests the hypotheses that the northeastern Pacific distribution has been influenced by post‐glacial colonization and lake elevation and that clade identity is associated with certain morphological attributes such as reduction in body armour. Location Lakes and nearshore marine environments of the eastern Pacific Basin from southcentral Alaska to southeastern British Columbia, (BC) Canada. Methods Restriction enzyme analysis of polymerase chain reaction‐amplified mitochondrial DNA fragments (cytochrome b ) from a total of 45 new populations combined with existing data for a further 45 populations. Lake elevation data were collected for 78 localities and tested for an association with mtDNA clade by contingency table analyses. Morphological data were collected on sticklebacks from eight samples representing four lake‐stream systems and tested for differentiation among populations with different mtDNA clade identities using analyses of variance. Results We extend the known distribution of the haplotypes diagnostic of the Trans‐North Pacific Clade (TNPC) southward to mid‐Vancouver Island and, for the first time, on mainland BC, in other island populations far from putative refugia, and in nearby anadromous populations. A morphological analysis indicated that the mainland population with the TNPC was not characterized by reduced spine or lateral plate (‘armour’) traits that characterize some putative relict populations on the Queen Charlotte Islands. We found a significant association between lake elevation and the presence of the TNPC; the TNPC was present more often in lakes located at or lower than 42 m than in higher elevation lakes. Main conclusions Our data support the hypothesis that post‐glacial colonization by TNPC‐bearing marine sticklebacks and aspects of lake ‘accessibility’ were important in determining the distribution of mtDNA clades in the eastern Pacific Ocean basin. More generally, our study demonstrates how processes acting both across immense geographic scales (e.g. pan‐Pacific dispersal) and local scales (lake accessibility contingent on timing and extent of isostatic rebound) may interact to explain biogeographical patterns.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".