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topical membership is not evidence of a direct dietary effect.\nplain_language: Excess developmental signaling changed segment identity.\norganism: Mus musculus\ntissue_or_cell_type: Embryonic hindbrain\nexperimental_model: RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy.\nlimitations: Not a quantitative human teratogenic threshold.\nevidence_locator: Abstract\nexposure: Experimental excess RA exposure\n[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","model_system":"RA-exposed preheadfold transgenic mouse embryos; lacZ and anatomy.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. 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