Restorative Regeneration of Digital Tips in the African Clawed Frog (<i>Xenopus laevis</i> Daudin)
Bibliographic record
Abstract
Localized, specialized structures are carried on the tips of digits of many amniote and certain non-amniote tetrapods. The pes of some members of Pipidae represents a rare example among tetrapods of differential expression of digital tip form (clawed vs. non-clawed digits). As a step towards understanding how such localized forms are generated and maintained, we conducted a series of amputation experiments and observed, through the process of regeneration, the potential for reconstitution, at the tissue and organ level, of the different digit tip morphologies. Results of this study reveal that immediately following metamorphosis specialized digit tip structures are regenerated with a high degree of structural and spatial accuracy by a process that essentially replicates normal development in recently metamorphosed Xenopus laevis froglets. Furthermore, this regenerative capacity is maintained in juveniles 4 months beyond metamorphosis, and also in adults of 1 year or more in age, indicating that metamorphosis-specific conditions do not exclusively facilitate regeneration of digit tips. In addition, regenerative capacity is maintained through repeated bouts of amputation and regeneration, indicating deep-seated digit identity and retention of the distinct digit tip developmental programs within the digits. Together, these data suggest that the developmental programing responsible for the formation of the discrete digital tip morphologies is located regionally within each digit, and that it is retained through time. Our results suggest that Xenopus can serve as a model organism for exploring the molecular underpinnings of digit tip formation because regeneration leads to morphologically identical structures to those of the original digit tips.
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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".