assertion  retraction  graph  subject    predicate        object     datatype    annotation
1          0           graph  DOID:6576  rdfs:subClassOf  DOID:4992  _IRI        
1          0           graph  DOID:4992  oio:id           DOID:4992  xsd:string  
1          0           graph  DOID:4991  rdfs:subClassOf  DOID:4992  _IRI