Gene Expression Analysis Provides Insights Into the Functional and Developmental Differentiations of Pleopodal Lungs in a Terrestrial Isopod Crustacean, <i>Porcellio scaber</i>
Bibliographic record
Abstract
Acquisition of air-breathing organs was one of the key events in the diversification of arthropods. Among terrestrial arthropods, isopod crustaceans have evolved a unique air-breathing structure called the pleopodal lung, which is located in their abdominal appendages (pleopods), while retaining pleopodal gills. These lungs offer an intriguing model for studying the evolution of respiratory organs during arthropod terrestrialization. However, the molecular mechanisms underlying lung function or development in isopods remain poorly understood. In this study, we conducted comparative transcriptomic analyzes using the common rough woodlouse, Porcellio scaber, in which pleopods with and without lungs are adjacent to each other. The results revealed distinct gene expression profiles linked to the structure and function of pleopods, including genes involved in morphogenesis. In particular, candidate lung development regulatory genes that were expressed specifically in the exopods of the second pleopods during the manca 1 stage were identified. Transcriptome analysis and immunohistochemistry suggested that the Hox gene abdominal-A is involved in lung formation. However, the two genes previously implicated in respiratory organ formation in pancrustaceans, trachealess and ventral veins lacking, did not show lung-related expression. Our comparison of gene expression patterns between exopods with and without lungs suggest that the function of gas exchange in the pleopodal lungs may be influenced by structural differences resulting from changes in developmental processes. Overall, this study provides essential insights into the molecular mechanisms underlying pleopodal lung development and sets the foundation for future evolutionary research.
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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".