The Highly Reduced Plastome of Mycoheterotrophic<i>Sciaphila</i>(Triuridaceae) Is Colinear with Its Green Relatives and Is under Strong Purifying Selection
Why this work is in the frame
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Bibliographic record
Abstract
The enigmatic monocot family Triuridaceae provides a potentially useful model system for studying the effects of an ancient loss of photosynthesis on the plant plastid genome, as all of its members are mycoheterotrophic and achlorophyllous. However, few studies have placed the family in a comparative context, and its phylogenetic placement is only partly resolved. It was also unclear whether any taxa in this family have retained a plastid genome. Here, we used genome survey sequencing to retrieve plastid genome data for Sciaphila densiflora (Triuridaceae) and ten autotrophic relatives in the orders Dioscoreales and Pandanales. We recovered a highly reduced plastome for Sciaphila that is nearly colinear with Carludovica palmata, a photosynthetic relative that belongs to its sister group in Pandanales, Cyclanthaceae-Pandanaceae. This phylogenetic placement is well supported and robust to a broad range of analytical assumptions in maximum-likelihood inference, and is congruent with recent findings based on nuclear and mitochondrial evidence. The 28 genes retained in the S. densiflora plastid genome are involved in translation and other nonphotosynthetic functions, and we demonstrate that nearly all of the 18 protein-coding genes are under strong purifying selection. Our study confirms the utility of whole plastid genome data in phylogenetic studies of highly modified heterotrophic plants, even when they have substantially elevated rates of substitution.
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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 it