EVOLUTION OF TRIPLOIDY IN APIOS AMERICANA (LEGUMINOSAE) REVEALED BY GENEALOGICAL ANALYSIS OF THE HISTONE H3-D GENE
Bibliographic record
Abstract
Autotriploidy is normally considered to be maladaptive in plants because of its association with high levels of sterility. Nonetheless, triploid individuals are found in many plant species and play important roles in plant evolution, in particular as a first step toward tetraploid formation. However, few studies have addressed the evolutionary potential of triploid lineages, which may principally suffer from the impossibility of combining useful mutations in a single genome due to their low fertility. Therefore, triploids acquire genetic diversity only via recurrent evolution and somaclonal mutation. This study evaluates the potential of multiple origins of polyploidy as a source of genetic diversity in Apios americana, a North American legume that possesses both diploid and triploid populations. Ploidy level determination via flow cytometry shows that triploids are mainly restricted to the portion of eastern North America that was covered by ice during the Wisconsinan glaciation 18,000 years ago. This distribution implies that either selection or postglaciation colonization played a role in shaping this cytogeographic pattern. A haplotype network of the single copy nuclear histone H3‐D gene reconstructed using statistical parsimony, together with single‐strand conformational polymorphism analysis, shows that autotriploidy evolved at least three times in this species and that heterozygosity is high in triploids. The genetic diversity found in A americana resulting from recurrent evolution and fixed heterozygosity increases the likelihood of producing successful genotypes and may give the opportunity for triploids to be better fit than diploids in new habitats. This suggests that triploid lineages can exhibit evolutionary potential of their own, and do not serve solely as a first step toward tetraploid formation.
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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 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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".