Experimental (Tamoxifen‐Induced) Manipulation of Female Reproduction in Zebra Finches (<i>Taeniopygia guttata</i>)
Bibliographic record
Abstract
Experimental manipulation of reproductive phenotype is a potentially powerful approach for understanding the fitness relationships of traits such as egg size, egg composition, and egg number. In this study, I investigated the effect of the antiestrogen tamoxifen on multiple, estrogen-dependent reproductive traits in female zebra finches (Taeniopygia guttata). Short-term tamoxifen treatment of egg-laying females (two daily injections before laying) had no effect on the timing or the pattern of egg laying compared to sham controls. However, tamoxifen treatment caused (1) a marked, but transient, decrease in egg size; (2) increased within-clutch egg-size variation; (3) a reduction in plasma vitellogenin (VTG) levels; and (4) lower dry yolk and yolk protein content of tamoxifen-treated females. Plasma levels of the second yolk precursor, very low density lipoprotein (VLDL), were not affected by tamoxifen, and tamoxifen appeared to have no effect on oviduct function in egg-laying females. These results are consistent with tamoxifen blocking estrogen receptors in the liver, suppressing VTG production, and decreasing the plasma pool of yolk precursors below a level required to maintain yolk formation at the normal rate. Tamoxifen treatment can therefore be used successfully to manipulate several components of the female reproductive phenotype (egg composition, intraclutch egg-size variation) to further explore the fitness consequences of these traits.
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How this classification was reachedexpand
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) | 0.001 | 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 teacher head, 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".