{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.epiboly","code":"thing-q1484637","url":"https://ver.cy/models/thing/q1484637/","name":"Epiboly","alternateNames":[],"kind":"thing","status":"published","version":"0.1.0-research.1","language":"en","classifiers":{"family":"Thing Registry","category":"Activities and processes","entryKind":"thing","plane":"ACT","domain":["ACT.PRC"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"Epiboly is a morphogenetic movement in which a tissue sheet thins and spreads over underlying cells or yolk, contributing to embryonic coverage and body organisation during early development.","purpose":"Enable an agent to recognise epiboly, assess the progress and coordination of tissue spreading, and identify evidence needed to explain or investigate abnormal progression.","scope":{"in":["Recognition of an epibolic movement in a specified embryo and tissue","Changes in tissue coverage, thickness and advancing-margin geometry","Coordination between spreading tissues and their underlying substrate","Cell behaviours and mechanical processes implicated in spreading","Progression, completion and experimentally observed disruptions"],"out":["Gastrulation as a whole and its complete sequence of movements","Germ-layer specification and lineage determination except as context for identifying participants","Invagination, involution, ingression and convergence-extension as independently modelled processes","Complete anatomy or developmental staging of a species","General molecular functions of adhesion proteins and cytoskeletal regulators","Wound closure and pathological tissue overgrowth unless separately established as within this registry entry"],"boundaries":[]},"distinguishingFeatures":["Require evidence of tissue spreading across an underlying surface; displacement of a cell group alone does not establish epiboly.","Assess spreading together with tissue thickness and cell rearrangement; increased tissue size alone can reflect growth without establishing epibolic deformation.","Distinguish outward surface coverage from inward bending, rolling or individual-cell internalisation, while allowing these movements to occur concurrently.","Distinguish increased surface coverage from tissue narrowing and elongation; document coupled convergence-extension without treating the two processes as interchangeable.","Treat zebrafish yolk enclosure as a species-specific instance, not a requirement that every epiboly event possess a yolk syncytial layer."],"structure":{"bundles":[{"id":"epibolic-identity","name":"Epibolic identity","description":"Establish whether the recorded event is epiboly and define the biological instance.","layers":[{"id":"movement-recognition","name":"Movement recognition","description":"Identify surface spreading and its relationship to tissue deformation.","findings":[{"id":"spreading-over-substrate","name":"Spreading over a substrate","description":"Record which tissue expands over which surface and what observations establish the movement. Zebrafish blastoderm spreading over the yolk provides one experimentally studied instance. [Primary research](https://pmc.ncbi.nlm.nih.gov/articles/PMC5773767/)","questions":[{"text":"Which tissue spreads over which underlying surface in this instance?","id":"spreading-over-substrate-q01","kind":"definition"},{"text":"What time-resolved evidence separates surface spreading from translation or growth alone?","id":"spreading-over-substrate-q02","kind":"boundary"}]}]},{"id":"instance-and-neighbours","name":"Instance and neighbouring movements","description":"Bind the process to an embryo and separate concurrently occurring movements.","findings":[{"id":"developmental-event-boundary","name":"Developmental event boundary","description":"Record species, tissue identity and event limits, with separate annotations for internalisation or axis-elongating movements.","questions":[{"text":"Which embryo, species and staging reference identify this epiboly event?","id":"developmental-event-boundary-q01","kind":"provenance"},{"text":"Which observed movements are assigned to epiboly, and which require linked models for other gastrulation movements?","id":"developmental-event-boundary-q02","kind":"boundary"}]}]}]},{"id":"coverage-and-deformation","name":"Coverage and deformation","description":"Describe how the spreading tissue changes shape relative to the embryo.","layers":[{"id":"surface-and-margin","name":"Surface and margin","description":"Define the reference geometry and quantify boundary advancement.","findings":[{"id":"explicit-coverage-convention","name":"Explicit coverage convention","description":"Keep measured surface coverage, axial margin position and conventional percentage-stage labels distinct unless their conversion is specified.","questions":[{"text":"Does the reported percentage denote surface area, normalised margin position or a published staging convention?","id":"explicit-coverage-convention-q01","kind":"measurement"},{"text":"Which anatomical landmarks and geometric reconstruction define the reference surface?","id":"explicit-coverage-convention-q02","kind":"measurement"}]}]},{"id":"thinning-and-uniformity","name":"Thinning and uniformity","description":"Relate area expansion to local thickness and spatial differences.","findings":[{"id":"local-deformation-pattern","name":"Local deformation pattern","description":"Record thickness and margin trajectories at multiple positions rather than inferring uniform deformation from one view.","questions":[{"text":"How does tissue thickness change at matched positions as coverage increases?","id":"local-deformation-pattern-q01","kind":"measurement"},{"text":"Which regions advance unevenly, and could projection or embryo orientation explain the apparent asymmetry?","id":"local-deformation-pattern-q02","kind":"measurement"}]}]}]},{"id":"participating-tissues","name":"Participating tissues","description":"Identify the spreading populations, substrate and coordination between them.","layers":[{"id":"tissue-specific-participants","name":"Tissue-specific participants","description":"Record anatomical participants without imposing teleost anatomy on other organisms.","findings":[{"id":"identified-layer-roster","name":"Identified layer roster","description":"In zebrafish, distinguish the enveloping layer, deep cells and yolk syncytial layer; establish the applicable participants independently in other species. [Primary research](https://pmc.ncbi.nlm.nih.gov/articles/PMC5773767/)","questions":[{"text":"Which labels, lineage observations or anatomical criteria identify each participating population?","id":"identified-layer-roster-q01","kind":"provenance"},{"text":"Which zebrafish tissue terms are applicable here, and which would create an unsupported equivalence?","id":"identified-layer-roster-q02","kind":"boundary"}]}]},{"id":"intertissue-coordination","name":"Intertissue coordination","description":"Track relative motion and contact between identified participants.","findings":[{"id":"relative-margin-motion","name":"Relative margin motion","description":"Assess synchrony through tissue-specific trajectories and interface observations rather than a shared whole-embryo score.","questions":[{"text":"How do the positions and velocities of the identified tissue margins differ through time?","id":"relative-margin-motion-q01","kind":"measurement"},{"text":"What observations support maintained contact, slippage or separation between participating tissues?","id":"relative-margin-motion-q02","kind":"measurement"}]}]}]},{"id":"spreading-mechanisms","name":"Spreading mechanisms","description":"Connect observed deformation with cellular behaviours and tested mechanical explanations.","layers":[{"id":"cellular-contributions","name":"Cellular contributions","description":"Resolve how individual cell behaviours contribute to tissue expansion and thinning.","findings":[{"id":"observed-cell-rearrangement","name":"Observed cell rearrangement","description":"Treat flattening, radial intercalation, neighbour exchange and division as candidate contributions to test in the specified tissue.","questions":[{"text":"Which tracked cells flatten or change position through the tissue thickness during spreading?","id":"observed-cell-rearrangement-q01","kind":"measurement"},{"text":"What evidence separates contributions from cell rearrangement, division and changes in individual cell shape?","id":"observed-cell-rearrangement-q02","kind":"measurement"}]}]},{"id":"mechanical-explanations","name":"Mechanical explanations","description":"Distinguish measured forces and perturbation results from inferred driving mechanisms.","findings":[{"id":"force-generation-and-transmission","name":"Force generation and transmission","description":"Record competing explanations with tissue and stage limits. Zebrafish experiments have implicated cortical contractility, differential tension and membrane removal in epiboly mechanics. [Primary research](https://pubmed.ncbi.nlm.nih.gov/28590839/)","questions":[{"text":"Which tissue is proposed to generate force, and what measurements support force transmission to the spreading tissue?","id":"force-generation-and-transmission-q01","kind":"provenance"},{"text":"Which perturbation and control could distinguish altered force production from altered adhesion or general tissue damage?","id":"force-generation-and-transmission-q02","kind":"action"}]}]}]},{"id":"progression-and-disruption","name":"Progression and disruption","description":"Judge the event's course, completion and response to experimental conditions.","layers":[{"id":"trajectory-and-completion","name":"Trajectory and completion","description":"Define onset, continued progression and completion for the particular instance.","findings":[{"id":"contextual-progress-state","name":"Contextual progress state","description":"Assign state from a documented observation interval and an anatomical endpoint appropriate to the species and tissue.","questions":[{"text":"What observable landmarks define initiation and completion in this species?","id":"contextual-progress-state-q01","kind":"definition"},{"text":"Over what interval and at what temporal resolution was advancement absent before the event was called stalled?","id":"contextual-progress-state-q02","kind":"measurement"}]}]},{"id":"defects-and-follow-up","name":"Defects and follow-up","description":"Assess abnormal trajectories and choose observations that resolve their interpretation.","findings":[{"id":"specificity-of-disruption","name":"Specificity of disruption","description":"Record treatment timing, affected tissues, matched controls and recovery evidence before attributing an abnormal embryo to an epiboly-specific defect.","questions":[{"text":"What evidence distinguishes impaired epiboly from general developmental delay, cell loss or imaging-induced damage?","id":"specificity-of-disruption-q01","kind":"boundary"},{"text":"Would longer observation, tissue-specific tracking or a controlled rescue most directly resolve the suspected defect?","id":"specificity-of-disruption-q02","kind":"action"}]}]}]},{"id":"evidence-and-external-alignment","name":"Evidence and external alignment","description":"What the world already says about this thing, gathered so the model can be checked against it.","layers":[{"id":"reported-evidence","name":"Reported evidence","description":"Findings from the breadth pass, kept separate from the structural claims.","findings":[{"id":"evidence-confidence-notes","name":"Check these first","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these check these first hold for the sense of Epiboly this model covers, and on what evidence?","id":"evidence-confidence-notes-q01","kind":"provenance"}]},{"id":"evidence-real-world-use","name":"Real-world use","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these real-world use hold for the sense of Epiboly this model covers, and on what evidence?","id":"evidence-real-world-use-q01","kind":"provenance"}]},{"id":"evidence-measurements","name":"Typical measurements","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these typical measurements hold for the sense of Epiboly this model covers, and on what evidence?","id":"evidence-measurements-q01","kind":"provenance"}]},{"id":"evidence-failure-modes-and-hazards","name":"Failure modes and hazards","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these failure modes and hazards hold for the sense of Epiboly this model covers, and on what evidence?","id":"evidence-failure-modes-and-hazards-q01","kind":"provenance"}]},{"id":"evidence-neighbours","name":"Neighbouring kinds and how to tell them apart","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these neighbouring kinds and how to tell them apart hold for the sense of Epiboly this model covers, and on what evidence?","id":"evidence-neighbours-q01","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Explain epiboly and its role in development from scientific sources.","Annotate imaging data from approved developmental studies."],"mustNot":["Misrepresent findings from embryo studies or invent results.","Assist in animal experiments without approved ethics review.","Apply findings from model organisms to humans without stating the limits."],"requiresHuman":["Approving experiments on vertebrate embryos."]},"ethics":{"considerations":["Research on embryos raises questions about animal welfare and the limits of use.","Overstated claims mislead patients and the public."],"affectedParties":["Research animals","Researchers","The public"]},"owners":{"steward":"Nobody owns the process; research institutions answer for the studies.","roles":[],"masterSystems":[]},"relations":[{"target":"Q14873676","type":"parent","note":"registry parent class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.epiboly","Wikidata: Q1484637 (https://www.wikidata.org/wiki/Q1484637)"]},"properties":{"applicability":"not-applicable","items":["Developmental context: Species, embryo identifier, developmental stage and staging reference","Spreading tissue and substrate: Named tissue or cell population linked to the surface it covers","Coverage: Percent of a defined reference surface, or a named staging convention with its formula","Tissue thickness: Micrometres or cell layers at specified positions and times","Margin position and velocity: Micrometres, degrees or normalised coordinates; corresponding change per minute","Layer coordination: Separation between identified margins in micrometres or time lag in minutes","Observed cell behaviour: Flattening, radial intercalation, neighbour exchange, division, other documented behaviour or unresolved","Progression state: Not initiated, progressing, delayed relative to reference, stalled within observation window, completed or indeterminate"]},"recognition":{"applicability":"optional","items":["Time series microscopy shows a tissue sheet expanding its coverage over underlying embryonic material.","The spreading sheet becomes thinner as its surface coverage increases.","In embryos with a prominent yolk mass, the tissue margin advances around the yolk rather than folding inward as a localized pocket."]},"capabilities":{"applicability":"required","items":["Classify a recorded tissue movement as epiboly, a coupled movement or an unresolved candidate.","Measure coverage, thinning and margin advance from calibrated time-series observations.","Compare tissue-specific progression with a species- and condition-matched reference.","Locate asymmetric spreading, persistent uncovered regions or separation between participating margins.","Compare candidate cellular and mechanical explanations against direct observations and perturbation evidence.","Select follow-up observations that distinguish delayed progression from persistent failure."]},"hazards":{"applicability":"required","items":["Disrupted tissue spreading can contribute to incomplete embryonic coverage and abnormal development.","Confusing epiboly with other tissue movements can lead to incorrect developmental staging or mechanistic conclusions.","Observation conditions that damage embryos can create apparent abnormalities and compromise research findings."]},"interfaces":{"applicability":"not-applicable","items":[]},"context":{"applicability":"required","items":["Epiboly is studied in developmental biology when embryonic tissues spread over underlying cells or yolk.","Microscopy and tissue tracking are used to compare its timing, coverage and coordination across embryos and experimental conditions."]}},"sources":[{"title":"Wikidata item Q1484637: Epiboly","url":"https://www.wikidata.org/wiki/Q1484637","note":"identity and sense of the item"},{"title":"Wikipedia: Epiboly","url":"https://en.wikipedia.org/wiki/Epiboly","note":"general description of the item"}],"openQuestions":["Does vr.tr.epiboly intend only embryological epiboly, or does its missing registry definition permit additional biological usages?","Which cross-species definition handles tissue spreading with little measurable thinning without becoming indistinguishable from growth?","Which participating tissues and mechanisms can be compared across taxa without assuming homology from similar movement?","How should published percentage-epiboly conventions be mapped to measured geometry without treating unlike quantities as equivalent?","Which species-, stage- and condition-specific reference trajectories justify thresholds for delay, arrest and completion?"],"resources":{"spec":"/models/things/publications/thing-q1484637/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q1484637/spec.json"],"providers":["Codex"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T09:30:47Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"not-applicable","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-07T10:10:26+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass","interaction.properties":"Plane ACT: no invented physical properties.","interaction.interfaces":"No specific standard, law or official classification applies universally to epiboly itself."},"score":1.0}}