Loss of Vertically-Inherited Totiviruses and Toxin-Encoding Satellites in Killer Yeast Evidences Intracellular Conflict in Natural Populations
Bibliographic record
Abstract
Abstract Saccharomyces cerevisiae is occasionally infected by totiviruses and their toxin-encoding satellites. Totiviruses and their satellites coexist but with an asymmetric dependence on the totivirus for maintenance inside the host cell. Satellites provide their yeast hosts with inhibitory toxins and the necessary self-immunity; loss of the satellite equates to loss of immunity. Because mycoviruses lack known extracellular stages, and sex is considered rare, mycoviruses are assumed to be transmitted vertically, implying infection states should correlate with host genotypes. However, totivirus–satellite coinfections are rarely examined in natural populations, leaving their associations with host genotypes poorly understood. We screened a multiyear population of S. cerevisiae isolates from New Zealand to examine the stability of host-virus associations over time, both within and across genotypes. While 55% of wild isolates harbored infections, only 37% of these included toxin-encoding satellites. Genotypes that persisted across years typically maintained consistent infection states. However, we observed stepwise transitions including acquisitions of totiviruses and satellites. Genotypes clustered strongly by infection state, supporting vertical transmission while suggesting that outcrossing is not responsible for the mycovirus acquisitions. Despite infection changes, genotype clustering by infection state remained intact, suggesting transitions are transient and that host genotypes may have optimal totivirus-satellite infection states.
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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 | 0.001 |
| 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 | 0.001 |
| 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".