Repeated cases of allopatric divergence and secondary contact in cattail ( <i>Typha</i> ) speciation
Bibliographic record
Abstract
Abstract Understanding how speciation unfolds is a central goal of evolutionary biology. Historically, global climatic fluctuations have triggered allopatric diversification. Using genome-wide data, we reconstructed the phylogenetic relationships and demographic histories of five Typha species, a plant genus foundational to freshwater ecosystems, with widespread, partially sympatric ranges and at least one widespread, regionally invasive hybrid zone ( Typha × glauca ). Molecular clock and demographic analyses indicate that the species in this study diverged in the absence of gene flow, during periods roughly contemporaneous with population bottlenecks and expansions in Typha —likely triggered by geoclimatic events—and that this divergence was followed by secondary contact in more recent times. Genomic scans showed no evidence of selection with gene flow driving species differentiation, suggesting a minor role for sympatric ecological speciation underlying divergence. These observations are consistent with expectations for drift-driven allopatric speciation. Allopatric speciation in T. latifoli a and T. angustifolia , their low genetic differentiation, and the scarcity of ecological divergence in building their reproductive isolation could explain these species’ ability to hybridise.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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".