Repeatability, ephemerality and inconvenient truths in the speciation process
Bibliographic record
Abstract
Everyone appreciates the happy fiction that species conform to the simple theoretical convenience of a single panmictic population. In speciation genetics, a further standard simplification is that it is only those genetic differences that are fixed between diverging populations that need concern us in order to understand the accumulation of intrinsic barriers to reproduction. To a first approximation, of course, both of these assumptions are appropriate and theory based on them provides compelling insights into diverse evolutionary phenomena (Orr & Turelli ). But what else can we learn about the begetting of biodiversity, speciation, by considering explicitly some less convenient realities of natural populations? Specifically, how does genetic variation at incompatibility loci within a species influence interspecies hybridization upon secondary contact? And, in nature, how repeatable among distinct bouts of secondary contact are the genomic outcomes of hybridization? Mandeville et al. () tackle exactly this question in their new study in Molecular Ecology on five species of suckers, fish of the genus Catostomus, that overlap sympatrically in different portions of their subdivided ranges that occupy different rivers. They document substantial genomic heterogeneity in realized hybridization in nature, both among species pairs and among the source populations for hybrids of a given species pair. This imperfect repeatability of episodes of hybridization implies greater permeability of species barriers in some parts of their range, with intriguing consequences for how the integrity of species as independently evolving units could be susceptible to collapse.
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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 | 0.017 | 0.041 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.004 | 0.062 |
| Scholarly communication | 0.005 | 0.016 |
| Open science | 0.002 | 0.005 |
| Research integrity | 0.003 | 0.006 |
| Insufficient payload (model declined to judge) | 0.002 | 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".