PRotein Ontology (PRO) Release 48.0 (21-Jan-2016) There are 203034 PRO terms in the Protein Ontology. 55 terms are in the 'external' category. 410 terms are in the 'family' category. 23562 terms are in the 'gene' category. 8319 terms are in the 'sequence' category. 6668 terms are in the 'modification' category. 212 terms are in the 'complex' category. 28 terms are in the 'organism-family' category. 92752 terms are in the 'organism-gene' category. 68055 terms are in the 'organism-sequence' category. 2197 terms are in the 'organism-modification' category. 369 terms are in the 'organism-complex' category. 122 terms are in the 'union' category. 2516 terms have some kind of annotation, codifying the information from 1672 papers. 4442 connections to GO (1709 PRO terms). 292 connections to MOD (255 PRO terms). 620 connections to Pfam (373 PRO terms). 338 connections to SO (317 PRO terms). 349 annotations of a phenotype (342 PRO terms). The ontology includes a subset of terms from other ontologies and resources that are used for logical definitions.