Fluorescent Labeling in the Leopard Gecko Resolves Tooth Initiation Patterns in ovo and Suggests Origins of Post‐hatching Shedding Patterns
Notice bibliographique
Résumé
The unerupted teeth of the polyphyodont leopard gecko form a highly patterned array consisting of teeth arranged in diagonal lines from most to least mature. These gradients of tooth maturity and size were originally termed Zahnreihen. Little is known about how these arrays assemble in such a precise pattern. We therefore set out to follow the addition of teeth to the Zahnreihen in geckos. First we scanned 5 hatchlings with μCT to quantify the number and arrangement of teeth specified in ovo. All individuals had diagonally oriented Zahnreihen consisting of 4–5 teeth along the jaw arch. Embryos were fixed at several times prior to hatching to investigate the development of the Zahnreihen. The first teeth to mineralize in the maxilla become the anterior‐most members of the longest Zahnreihen (5 teeth long). Marginal teeth are added anteriorly and posteriorly to this region before the Zahnreihen elongate. Nonetheless, the relative positions of some developing teeth and total marginal tooth numbers differed between individuals at hatching. Contributing to this variability, in between larger teeth at the jaw margin, we identified small, mineralized structures in between larger marginal teeth that could be rudimentary teeth or newly initiating tooth positions (and possibly Zahnreihen). To clarify the identity of these small marginal structures, we performed a dual label experiment with calcein and xylenol orange to document mineralization of teeth in ovo (N = 3). Calcein was injected at stage 39 at a time when μCT scans show 13–14 mineralizing teeth per upper jaw quadrant. Xylenol orange was injected 5 days later, and then embryos were sacrificed just prior to hatching, 15 days after the xylenol injection. 3D imaging with optical projection tomography revealed that the smallest, lingual‐most teeth have only a xylenol label, indicating that the dyes are cleared from embryonic circulation despite being in the closed system of the egg. The small mineralized structures identified in the marginal tooth row were labeled with calcein, indicating that they represent rudimentary teeth initiated early in tooth patterning, not the interstitial addition of new tooth positions peri‐hatching. No unlabeled teeth were present along the jaw, so in the 15 days post‐labeling, no new teeth formed that could be detected within the resolution of our scans (9.55μm voxel size). The proportion of calcein to xylenol label within volume renderings of developing teeth revealed synchronous deposition of matrix across homologous teeth in adjacent Zahnreihen. Rudimentary teeth did not begin a Zahnreihe. Finer details of the labeling reveal small variations in matrix deposition among teeth of similar age. Our lab previously found that post‐hatching shedding patterns (wave replacement and smaller variations within it such as premaxillary/maxillary regionalization and fixed slight asymmetries) are maintained from when this first dentition is shed into later tooth generations. The results of this study suggest that consistent deviations in post‐hatching shedding patterns may come from in ovo patterning directly. Support or Funding Information National Sciences and Engineering Research Council, National Institutes of Health, Michael Smith Foundation for Health Research, Killam postdoctoral fellowship
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».