Component
Hindbrain segment identity
Hindbrain segment identity; model-specific measured outcome rather than a universal clinical endpoint.
1 recorded relationships. Experimental role, claim status and evidence remain attached to each record.
How nutrients influence it
Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.
Other things that act on it
Enzymes, hormones, genes, and other components with a recorded effect. These are not nutrients, so they do not count toward the arrows above. Each finding names the chapter that recorded it.
How nutrients reach it in more than one step
Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.
Tracing routes…
What it does
Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.
What acts on it
The exposed embryos showed rhombomere 2/3 transformation toward 4/5 identity with matching anatomical changes.
Experimental context and source evidence
- evidence_locator
- Abstract
- experimental_model
- RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy.
- exposure
- Experimental excess RA exposure
- limitations
- Not a quantitative human teratogenic threshold.
- nutrient_topic
- Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
- organism
- Mus musculus
- plain_language
- Excess developmental signaling changed segment identity.
- primary_references
- [va-marshall-1992] Retinoic acid alters hindbrain Hox code and induces transformation of rhombomeres 2/3 into a 4/5 identity (1992). https://www.nature.com/articles/360737a0 DOI: 10.1038/360737a0
- tissue_or_cell_type
- Embryonic hindbrain
Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 1435–1446
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy. · source_derived_draft · unverified_draft
### va-sig-excess-ra-hindbrain-identity The exposed embryos showed rhombomere 2/3 transformation toward 4/5 identity with matching anatomical changes. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Excess developmental signaling changed segment identity. organism: Mus musculus tissue_or_cell_type: Embryonic hindbrain experimental_model: RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy. limitations: Not a quantitative human teratogenic threshold. evidence_locator: Abstract exposure: Experimental excess RA exposure [va-marshall-1992] Retinoic acid alters hindbrain Hox code and induces transformation of rhombomeres 2/3 into a 4/5 identity (1992). https://www.nature.com/articles/360737a0 DOI: 10.1038/360737a0
Complete structured claim and evidence
The events it takes part in
A mechanism often involves more than two components. These are the full events, with every participant and its role.
Situations it appears in
Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.
In the sources
Preserved passages that mention this component, quoted exactly. Open one to read it in context.
Open hypotheses
Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.
This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.