Genomic Patterns of Loss of Distyly and Polyploidization in Primroses
Bibliographic record
Abstract
Transitions from outcrossing to selfing and from diploidy to polyploidy often co-occur in plants, likely because the ability to produce selfed seed increases the likelihood of newly formed polyploids to become established. An ideal system to study these transitions is Primula, where the shift from diploid, outcrossing progenitors to polyploid, selfing descendants co-occurred repeatedly and the genetic basis of the mating-system shift is known. In Primula, outcrossing is enforced in distylous, typically diploid species characterized by florally heteromorphic, self-incompatible individuals, whereas selfing is enabled in homostylous, typically polyploid species, characterized by florally homomorphic populations of self-compatible plants. Distyly is controlled by the S-locus supergene. Small loss-of-function mutations in the S-locus CYPT gene, which controls style length and female self-incompatibility, are associated with loss of heterostyly in diploid, ancestrally heterostylous Primula species. However, CYPT and the S-locus have never been investigated in interspecific shifts from distylous, diploid species to homostylous, polyploid species. By analyzing the first assembled genome of a homostylous, polyploid species (Primula grandis) in a comparative framework, we discovered two, nearly identical S-locus alleles in the same subgenome, consistent with the hypothesis that the species originated from a cross between a homostylous, diploid pollen donor and a long-styled, diploid pollen recipient. Conformant to theoretical predictions, the macroevolutionary loss of distyly coincided with considerable degeneration of CYPT, including multiple mutations and exon loss, while other S-locus genes remained largely unaffected. This study advances knowledge on the macroevolutionary dynamics of supergenes and genomes in shifts between breeding systems and ploidy levels.
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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 | 0.000 |
| 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) | 0.001 | 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".