assertion  retraction  graph  subject             predicate        object              datatype  annotation
1          0           graph  obo:UBERON_0000002  rdfs:subClassOf  obo:UBERON_0005156  _IRI      
1          0           graph  obo:UBERON_0013515  rdfs:subClassOf  obo:UBERON_0005156  _IRI      
1          0           graph  obo:UBERON_0000997  rdfs:subClassOf  obo:UBERON_0005156  _IRI