Molecular divergence and gene flow in cold ocean tunicates: insights from cytochrome oxidase 1
Bibliographic record
Abstract
Gaps in our ability to identify species and understand factors influencing the evolution of species ranges, limit the extent to which we can diagnose changes to ocean ecosystems that occur in response to anthropogenic stressors. DNA barcodes offer one method to facilitate our assessment and understanding of diversity. Tunicates are a group of marine invertebrates for which researchers have used the typical animal barcoding region of the cytochrome oxidase 1 (CO1) gene to identify cryptic species complexes and elucidate patterns of gene flow in non-indigenous ascidians. Waters surrounding Newfoundland contain several species of invasive ascidians and native appendicularian tunicates. My research utilized the CO1 animal barcoding region to explore the genetic structure of two cold ocean tunicates in Newfoundland waters, the native appendicularian tunicate, Oikopleura vanhoeffeni and the non-native ascidian Botryllus schlosseri. Specifically, I provide the first report of a partial CO1 sequence for O. vanhoeffeni and report on gene flow of B. schlosseri collected from Newfoundland waters. The CO1 gene proved unsuitable for further evaluation as a marker for species level identification in O. vanhoeffeni, because the presence of tandem repeat regions would require multiple primer pairs to amplify the CO1 barcoding region. Across Newfoundland harbours, considerable genetic structure among the 7 Botryllus schlosseri populations sampled indicates increasing genetic diversity from west to east. All of the B. schlosseri CO1 haplotypes identified in Newfoundland waters were recorded previously in Nova Scotian harbours, and a few in the Mediterranean Sea. Thus, regional boating traffic from mainland Atlantic Canada likely provided an important vector of introduction for this species in Newfoundland, but transoceanic and/or local boating traffic may play a role.
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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 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| 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 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".