Isozymes of the Isoetes riparia Complex, II. Ancestry and Relationships of Polyploids
Bibliographic record
Abstract
Abstract Isoetes riparia is a complex tetraploid taxon of eastern North America that in its widest sense includes a diversity of morphotypes variously segregated, or included in a single polymorphic species. Although the diploid ancestry of I. riparia has been proposed as I. echinospora × engelmannii, it is uncertain whether this ancestry applies to all elements of the complex, here broadly defined to encompass three segregates of I. riparia and the recently described I. hyemalis (referred to informally as riparia, canadensis, saccharata and hyemalis). To help clarify relationships among these tetraploids, isozyme genotypes for 13 loci coding eight enzymes, were determined for 16 populations representing all four segregates. Duplicate gene expression, evidenced as fixed heterozygosity consistent with allopolyploidy, characterized the tetraploid genotypes of all taxa. Although exhibiting modest to no variation within populations, populations were highly differentiated, most showing a unique combination of alleles for their multilocus genotypes, with the exception of five genetically identical Canadian populations. Ancestry was evaluated through comparison to diploid genotypes previously reported. A quantitative approach was carried out to rank likelihoods for hypothetical ancestral combinations of diploids for each tetraploid population. The ancestry I. echinospora × engelmannii hypothesized for I. riparia was unequivocally supported for the six populations of the most northern segregate, canadensis. Diploid ancestries for the remaining 10 more southern populations were less certain, although the diploid I. mattaponi was implicated as a likely ancestor for most. Most likely ancestry for populations of riparia/saccharata was inferred as I. valida × mattaponi, and for hyemalis as I. mattaponi × flaccida. However, these hypotheses were only slightly more likely than other combinations. UPGMA analysis using Rogers' similarity resulted in three clusters corresponding to canadensis, riparia/saccharata, and hyemalis. However, the hyemalis cluster was weakly associated and was not supported by UPGMA using Nei's identity. These highly variable tetraploid genotypes suggest a complicated evolutionary history for the I. riparia complex that probably involved a combination of diverse ancestry, multiple origins, divergence, and gene silencing. Communicating Editor: Anita Cholewa
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.001 | 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".