Peer Review #1 of "Trans-Arctic vicariance in Strongylocentrotus sea urchins (v0.2)"
Bibliographic record
Abstract
The sea urchins Strongylocentotus pallidus and S. droebachiensis first invaded the Atlantic Ocean from the Pacific following the opening of the Bering seaway in the late Miocene.While trans-Arctic dispersal during the Pleistocene is thought to have maintained species' integrity, a recent genomic analysis identified a reproductively isolated cryptic species within S. droebachiensis.Based on previous studies, the distribution of one of these lineages (S. droebachiensis w) includes the shallow water habitats of the northwest Atlantic and Pacific, while the other (S.droebachiensis e) is found throughout the shallow habitat in the northeast but is mostly restricted to deep habitats (>65m) in the northwest Atlantic.However, since genetic variation within S. droebachiensis has been largely unstudied in the north Pacific and Arctic oceans, the biogeography of the cryptic species is not well known, and it is difficult to identify the mechanisms driving population subdivision and speciation.Here we use population genetic analyses to characterize the distribution of each species, and to test hypotheses about the role of vicariance in the evolution of systematic and genomic divergence within the genus.We collected individuals of all 3 Strongylocentrotus species (n = 365) from 10 previously unsampled locations in the northeast Pacific and north Atlantic (Labrador Sea and Norway), and generated mtDNA sequence data for a 418 bp fragment of cytochrome c oxidase subunit I (COI).To assess the biogeography of all three species, we combined our alignment with 5 previously published data sets (total n = 789) and used statistical parsimony and maximum likelihood to identify species and characterize their distribution within and among oceans.Patterns of haplotype sharing, pairwise F ST , and hierarchical analyses of molecular variance (AMOVA) identified trans-Arctic dispersal in S. pallidus and S. droebachiensis w, but other than 5 previously reported singletons we failed to detect additional mtDNA haplotypes of S. droebachiensis e in the north Pacific.Within the Atlantic, patterns of habitat segregation suggests that temperature may play a role in limiting the distribution of S. droebachiensis e, particularly throughout the warmer coastal waters along the coast of Nova Scotia.Our results are consistent with the cycles of trans-Arctic dispersal and vicariance in S. pallidus
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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 | 0.012 | 0.076 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.005 | 0.003 |
| Science and technology studies | 0.004 | 0.001 |
| Scholarly communication | 0.005 | 0.003 |
| Open science | 0.002 | 0.004 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.168 | 0.072 |
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".