Genomic evidence unveils the genetic architecture and evolution of the <i>S</i>‐locus controlling heterostyly in Rubiaceae
Bibliographic record
Abstract
The S-locus supergene controlling heterostyly has multiple angiosperm origins and is characterized by convergent evolution in form and function. The genetic architecture of floral polymorphism has been studied in several unrelated families, but not Rubiaceae, which has the largest number of heterostylous species. We assembled genomes of the long- and short-styled morphs of distylous Mussaenda lancipetala and investigated the structure and evolution of the S-locus in three Mussaenda species to evaluate evidence for convergence in genetic architecture and gene function in unrelated families. Genome assemblies and population genomics indicated that the S-locus in M. lancipetala is comprised of three hemizygous genes - MuIAA, MuGA3ox, and MuAPs - present only in the S-morph. In each species, MuIAA, involved in the auxin response pathway, was highly expressed in pistils and floral tubes of the S-morph, and is a likely candidate gene controlling style length. Molecular evolution analysis indicated that the S-haplotype has accumulated repetitive sequences, S-linked genes showed no evidence of relaxed purifying selection, and the evolutionary assembly of the S-locus involved stepwise duplication. Our findings provide support for the prevalence of hemizygosity in S-locus genes and have identified molecular pathways underpinning convergent morphological evolution of clear adaptive significance.
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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 | 0.000 | 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) | 0.001 | 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".