Sexing Frogs by Real-Time PCR: Using Aromatase <b><i>(cyp19) </i></b>as an Early Ovarian Differentiation Marker
Why this work is in the frame
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Bibliographic record
Abstract
Most anurans have no identified sex-markers; therefore, alternative methods for identification of early changes in sex ratios are required. In this study, Lithobates sylvaticus and Silurana tropicalis tadpoles were sampled at different developmental stages covering the entire process of sex differentiation. Three candidate genes known to be involved in sex differentiation in other vertebrate species were selected to develop a method to identify phenotypic sex in frogs: cytochrome p450 aromatase (cyp19), forkhead box L2 (foxl2) and the cytochrome 17-alpha-hydroxylase/17,20 lyase (cyp17). Cloning of these genes revealed nucleotide identity values ranging between 75-97% when compared to other amphibian species. Gene expression of cyp17,cyp19 and foxl2 in L. sylvaticus adult gonads and gonad-mesonephros complex (GMC) of tadpoles was analyzed by real-time RT-PCR. Results showed clear sexually dimorphic patterns in the expression of the 3 genes. Our analysis reveals that GMC gene expression levels of cyp19 alone can be used as a robust predictor of phenotypic sex in L. sylvaticus tadpoles. In addition, we validated this method measuring cyp19 mRNA levels in S. tropicalis GMCs. We propose measuring cyp19 as a tool to study the effects of chemical contaminants (including endocrine disrupting compounds) on amphibian gonadal development and sex ratios in the future.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| 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 it