Chromosomal fission accounts for small-scale radiations in Zamia (Zamiaceae; Cycadales)
Bibliographic record
Abstract
Zamia is unique among Cycadales in its diversity of morphology, ecology and chromosome numbers. The chromosome numbers in Zamia range from 16 to 28, excluding 20, manifest as both interspecific and intraspecific series. It has long been recognized that Robertsonian transformations (chromosomal fission or fusion) probably dominate karyotype evolution in Zamiaceae, although it has been debated whether chromosome numbers are increasing or decreasing. We re‐analyse published karyotypes of Zamia spp., relating both chromosome forms and sizes to recent phylogenetic data. We show that karyotype evolution is most probably moving towards increased asymmetry, with higher numbers of smaller chromosomes, thus supporting chromosomal fission. We also address additional hypotheses for increasing chromosome numbers, namely pericentric inversions and unequal translocations. Finally, we discuss the role of these chromosomal changes in evolutionary radiations.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".