---
layout: rule
id: GORULE:0000006
title: "IEP and HEP usage is restricted to terms from the Biological Process ontology, except when assigned by GOC"
type: filter
fail_mode: hard
status: implemented
contact: "go-quality@lists.stanford.edu"
implementations:
  - language: python
    source: https://github.com/biolink/ontobio/blob/master/ontobio/io/qc.py
examples:
  fail:
    - comment: Fails because uses IEP with a molecular function term.
      format: gaf
      input: "GeneDB	PF3D7_0507500	SUB1		GO:0005634	PMID:12764150	IEP		F	subtilisin-like	protease 1	gene	NCBITaxon:36329	20090624	GeneDB"
    - comment: Fails because uses HEP with a molecular function term.
      format: gaf
      input: "GeneDB	PF3D7_0507500	SUB1		GO:0005634	PMID:12764150	HEP		F	subtilisin-like	protease 1	gene	NCBITaxon:36329	20090624	GeneDB"
    - comment: Fails because uses IEP with a cellular component term.
      format: gaf
      input: "GeneDB	PF3D7_0507500	SUB1		GO:0005634	PMID:12764150	IEP		F	subtilisin-like	protease 1	gene	NCBITaxon:36329	20090624	GeneDB"
  pass:
    - comment: Should pass
      format: gaf
      input: "GeneDB	PF3D7_0507500	SUB1		GO:0075317	PMID:12764150	IEP		F	subtilisin-like	protease 1	gene	NCBITaxon:36329	20090624	GeneDB"
---
The IEP and its high throughput equivalent, HEP, evidence codes are used where process involvement is inferred from
the timing or location of expression of a gene, particularly when
comparing a gene that is not yet characterized with the timing or
location of expression of genes known to be involved in a particular
process. This type of annotation is only suitable with terms from the
Biological Process ontology, except when the annotation comes from 
an inter ontology link, in which case all GO aspects are allowed.

For more information, see the [binding
guidelines](http://wiki.geneontology.org/index.php/Binding_Guidelines)
on the GO wiki.
Error report (number of errors) in [db_species]-summary.txt & owltools-check.txt (details).