Sex determination and gene expression in Daphnia magna exposed to juvenile hormone
Bibliographic record
Abstract
Abstract Daphnia spp. cycle between asexual and sexual reproduction depending on environmental conditions. Under favorable conditions, female offspring are produced, resulting in rapid population expansion; in less favorable conditions, males are produced, initiating the sexual portion of their lifestyle. Although mediated by environmental cues, sex determination is ultimately dependent on the expression of Doublesex genes, Dsx1 and Dsx2, in Daphnia. We exposed Daphnia magna to juvenile hormone III (JHIII), an insect hormone often mimicked by agricultural insecticides. Juvenile hormone (JH) and JH analogues disrupt the insect endocrine system, inhibiting reproduction; these chemicals pose an environmental threat to non-target organisms by leaching into surrounding waters. When Daphnia are exposed to JH or JH analogues, it causes a premature shift from asexual to sexual reproduction. We showed that Dsx1 is upregulated throughout vitellogenesis in female D. magna producing male offspring and Dsx2 is upregulated during late vitellogenesis, suggesting that both Dsx1 and Dsx2 contribute to male sex determination. In addition, Dsx2 expression increases during sexual maturation in male D. magna, suggesting that it also plays a role in spermatogenesis. In addition, exposure to JHIII decreased reproductive output, slowed growth and prematurely shifted D. magna reproductive strategy to the sexual portion of their lifecycle.
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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".