Evolution of the Mitochondrial Genomes of Gall Midges (Diptera: Cecidomyiidae): Rearrangement and Severe Truncation of tRNA Genes
Bibliographic record
Abstract
We determined the complete mitochondrial genome sequences of two species of gall midges (Diptera: Cecidomyiidae), as well as partial sequence from a third cecidomyiid and a species from a related family, the Sciaridae. The sciarid sequence has a number of rearrangements of tRNA genes, relative to other dipterans, but is otherwise unremarkable. In contrast, the cecidomyiid genomes possess a number of very unusual features. First, the two complete sequences are very small compared with other dipteran mitochondrial genomes. The genome of Mayetiola destructor is only 14,759 bp while that of Rhopalomyia pomum is only 14,503 bp, comparable with genome sizes observed in some arachnids. Second, all three cecidomyiid species have very high A + T content--more than 83% for the coding region. Third, all three cecidomyiid species possess a number of rearrangements of tRNA genes, including variations within the family. Fourth, the most extraordinary feature of cecidomyiids examined in this study is an extreme truncation of all tRNA genes, including the loss of TPsiC arms and apparent absence of the 3' part of the aminoacyl stems.The truncated tRNA genes of cecidomyiids are very similar to those previously reported for spiders and appear to represent a second, independent origin of these structural features. It is likely that they are made functional through RNA editing, perhaps using the 5' end of the aminoacyl stem as a template for the construction of the required 3' end.
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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) | 0.000 | 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 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".