The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP1066_r118352 http://rdf.wikipathways.org/Pathway/WP1066_r118352/DataNode/f15 (POLR2J)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier