Evolutionary Relationships of Apusomonads Inferred from Taxon-Rich Analyses of 6 Nuclear Encoded Genes
Bibliographic record
Abstract
The phylogenetic relationships of the biflagellate protist group Apusomonadidae have been unclear despite the availability of some molecular data. We analyzed sequences from 6 nuclear encoded genes-small-subunit rRNA, large-subunit rRNA, alpha-tubulin, beta-tubulin, actin, and heat shock protein 90-to infer the phylogenetic position of Apusomonas proboscidea Aléxéieff 1924. To increase the taxon richness of the study, we also obtained new sequences from representatives of several other major eukaryotic groups: Chrysochromulina sp. National Institute for Environmental Studies 1333 (Haptophyta), Cyanophora paradoxa (Glaucophyta), Goniomonas truncata (Cryptophyceae), Leucocryptos marina (Kathablepharidae), Mesostigma viride (Streptophyta, Viridiplantae), Peridinium limbatum (Alveolata), Pterosperma cristatum (Prasinophytae, Viridiplantae), Synura sphagnicola (Stramenopiles), and Thaumatomonas sp. (Rhizaria). In most individual gene phylogenies, Apusomonas branched close to either of the 2 related taxa-Opisthokonta (including animals, fungi, and choanoflagellates) or Amoebozoa. Combined analyses of all 4 protein-coding genes or all 6 studied genes strongly supported the hypothesis that Apusomonadidae is closely related to Opisthokonta (or to all other eukaryotic groups except Opisthokonta, depending on the position of the eukaryotic root). Alternative hypotheses were rejected in approximately unbiased tests at the 5% level. However, the strong phylogenetic signal supporting a specific affiliation between Apusomonadidae and Opisthokonta largely originated from the alpha-tubulin data. If alpha-tubulin is not considered, topologies in which Apusomonadidae is sister to Opisthokonta or is sister to Amoebozoa were more or less equally supported. One current model for deep eukaryotic evolution holds that eukaryotes are divided into primary "unikont" and "bikont" clades and are descended from a "uniflagellate" common ancestor. Together with other information, our data suggest instead that unikonts (=Opisthokonta and Amoebozoa) are not strictly monophyletic and are descended from biflagellate ancestors.
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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 | 0.000 |
| 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".