Difference between revisions of "KB build process"

From phenoscape
Jump to: navigation, search
(Axiom generation)
("Absence" classes for OWL EL negation classification workaround: more to come here, but for now see some documentation on Absence Phenotypes in OWL)
Line 138: Line 138:
 
==Axiom generation==
 
==Axiom generation==
 
==="Absence" classes for OWL EL negation classification workaround: more to come here, but for now see some documentation on [[Absence Phenotypes in OWL]]===
 
==="Absence" classes for OWL EL negation classification workaround: more to come here, but for now see some documentation on [[Absence Phenotypes in OWL]]===
We model absence phenotypes as an instance of the quality [http://purl.obolibrary.org/obo/PATO_0002000 lacks all parts of type] which ''inheres_in'' the [http://purl.obolibrary.org/obo/UBERON_0000468 whole organism] and is ''towards'' a type, the class of structure that is absent, i.e. ''towards'' value '''X'''. This approach allows us to have a phenotype class for the condition, but directly using a class as a property value in this way is outside of DL reasoning. So to classify our absence phenotypes, we also add an equivalence to <code>not (''has_part'' some '''X''')</code>.
+
We model absence phenotypes as an instance of the quality [http://purl.obolibrary.org/obo/PATO_0002000 lacks all parts of type] which ''inheres_in'' the [http://purl.obolibrary.org/obo/UBERON_0000468 whole organism] and is ''towards'' a type, the class of structure that is absent, i.e. <code>''towards'' value '''X'''</code>. This approach allows us to have a phenotype class for the condition, but directly using a class as a property value in this way is outside of DL reasoning. So to classify our absence phenotypes, we also add an equivalence to <code>not (''has_part'' some '''X''')</code>.
 +
 
 
===SPARQL facilitation (e.g. materialized existential hierarchies such as part_of)===
 
===SPARQL facilitation (e.g. materialized existential hierarchies such as part_of)===
 
==="EQ character" classes: combinations of anatomical entities and PATO attribute terms===
 
==="EQ character" classes: combinations of anatomical entities and PATO attribute terms===

Revision as of 16:16, 25 February 2014

Still being fleshed out

The Phenoscape KB build process goes through several steps in converting input data sources to a queryable knowledgebase. This page provides some description for each of the steps, most or all of which are implemented in the phenoscape-owl-tools project.

OWL conversion

The Phenoscape Knowledgebase works as a single unified OWL model. While some inputs (e.g. the shared ontologies such as Uberon and PATO) are natively distributed as OWL documents, others are converted to OWL from some other representation. In doing so the inputs are, as far as possible, converted to a shared data model. EQ annotations are converted to a specific semantic representation.

Examples

  • ZFIN phenotype annotations are provided at their data download site. We translate each row into a phenotype instance: an individual instance of some PATO quality. Here are the column headers from the ZFIN website, followed by representative OWL syntax (referencing column numbers where actual URI values would be, and somewhat casual with other identifiers):
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
ID Gene Symbol Gene ID Affected Structure or Process 1 subterm ID Affected Structure or Process 1 subterm Name Post-composed Relationship ID Post-composed Relationship Name Affected Structure or Process 1 superterm ID Affected Structure or Process 1 superterm Name Phenotype Keyword ID Phenotype Keyword Name Phenotype Tag Affected Structure or Process 2 subterm ID Affected Structure or Process 2 subterm name Post-composed Relationship (rel) ID Post-composed Relationship (rel) Name Affected Structure or Process 2 superterm ID Affected Structure or Process 2 superterm name Genotype ID Genotype Display Name Knockdown Reagent ID Start Stage ID End Stage ID Genotype Environment ID Publication ID Figure ID
 Individual: <uuid_1>
   Types: ps:AnnotatedPhenotype, 
          <uuid_2>
   Facts: ps:associated_with_gene <col_3>,
          ps:associated_with_taxon NCBITaxon:zebrafish, 
          dc:source <col_26>
 
 Class: <uuid_2>
   SubClassOf: <col_10> and (inheres_in some (<col_4> and (<col_6> some <col_8>))) and (towards some (<col_13> and (<col_15> some <col_17>)))


  • Annotations from other MODs are similarly structured; however some such as MGI use precoordinated phenotype classes instead of an EQ template. In that case, the phenotype instance is simply an instance of the stated MP phenotype term.

Identifier cleanup

Several common OWL properties (part_of, has_part, develops_from, etc.) are conceptually shared across ontology and annotation resources, facilitating data integration. However, unlike class identifiers, identifiers for properties are often not standardized and they may not properly reference shared terms (usually because of poor tool support rather than user intent). We maintain a table of "alternative" URIs for common properties as we observe them in our data inputs. We could create equivalence axioms between these, but instead we just standardize all incoming content. This saves the reasoner some work and also makes it much easier to query across data using standard URIs, especially when not using a reasoner.

Axiom generation

"Absence" classes for OWL EL negation classification workaround: more to come here, but for now see some documentation on Absence Phenotypes in OWL

We model absence phenotypes as an instance of the quality lacks all parts of type which inheres_in the whole organism and is towards a type, the class of structure that is absent, i.e. towards value X. This approach allows us to have a phenotype class for the condition, but directly using a class as a property value in this way is outside of DL reasoning. So to classify our absence phenotypes, we also add an equivalence to not (has_part some X).

SPARQL facilitation (e.g. materialized existential hierarchies such as part_of)

"EQ character" classes: combinations of anatomical entities and PATO attribute terms

Materialization of inferred axioms

ELK reasoner using extracted tbox axioms only (not feasible with individuals included).

Assertion of absence hierarchy

Based on inverse of hierarchy of negated classes computed by ELK.