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=RO - OBO Relation Ontology=
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= Announcement =
  
The main RO page is located on sourceforge: [http://obo.sourceforge.net/relationship]
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OBO_REL has been replaced by RO - the new website and wiki can be found at http://purl.obolibrary.org/obo/ro
  
You can browse the ontology and get e-mail list details there.
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Old material that was previously kept here has been moved to [[RO:Historic Material]]
 
 
=Open issues=
 
 
 
There's an RO expert meeting happening in May, 2008. See [[OntologyRelations]]
 
 
 
==Three types of relations==
 
 
 
The OBO Relation Ontology (aka the OBO Relationship Types Ontology) distinguished three families of relations, according to whether they hold between instances, types, or combinations thereof, for example:
 
 
 
*1. '''instance_of''' holding between an instance and a type
 
*2. '''part_of''' holding between an instance and an instance
 
*3. ''part_of'' holding between a type and a type
 
 
 
We use bold face to mark out those relational expressions used in ontologies such as GO to represent the relations between the types these ontologies represent.
 
 
 
In the original Genome Biology [http://genomebiology.com/2005/6/5/R46 paper] we focused primarily on defining relations of type 3. in terms of those of types 1. and 2. This was to meet the need among biologists for clear guidance as to what the relational expressions used in ontologies such as GO precisely mean.
 
 
 
In our treatment of relations of types 1. and 2. we focused primarily on picking out certain instance level relations which we fixed on as primitive -- meaning that they are so basic to the relational architecture of reality that they cannot be defined in terms of anything more basic. The primitive relations selected were as follows:
 
 
 
*c '''instance_of''' C '''at''' t - a primitive relation between a continuant instance and a class which it instantiates at a specific time
 
 
 
*p '''instance_of''' P - a primitive relation between a process instance and a class which it instantiates holding independently of time
 
 
 
*c '''part_of''' c1 '''at''' t - a primitive relation between two continuant instances and a time at which the one is part of the other
 
 
 
*p '''part_of''' p1, r '''part_of''' r1 - a primitive relation of parthood, holding independently of time, either between process instances (one a subprocess of the other), or between spatial regions (one a subregion of the other)
 
 
 
*c '''located_in''' r '''at''' t - a primitive relation between a continuant instance, a spatial region which it occupies, and a time
 
 
 
*r '''adjacent_to''' r1 - a primitive relation of proximity between two continuants
 
 
 
*t '''earlier''' t1 - a primitive relation between two times
 
 
 
*c '''derives_from''' c1 - a primitive relation involving two distinct material continuants c and c1
 
 
 
*p '''has_participant''' c '''at''' t - a primitive relation between a process, a continuant, and a time
 
 
 
*p '''has_agent''' c at '''t''' - a primitive relation between a process, a continuant and a time at which the continuant is causally active in the process
 
 
 
In proposing new relations (both on the [http://www.bioontology.org/wiki/index.php/RO:Main_Page#Proposed_new_relations wiki] and in the http://sourceforge.net/tracker/?group_id=76834&atid=947684&func=browse Sourceforge Tracker], please specify to which of the three types your proposed relation belongs.
 
 
 
If it is an instance-level relation please answer the following questions:
 
 
 
**a. is it already on the list above?
 
**b. is it primitive in the above-mentioned sense?
 
*If the answer to both of these questions is no,
 
**c. can it be defined in terms of the relations on the above list?
 
*If yes, please supply a definition (an example is provided below)
 
*If no, please propose also those primitive instance-level relations which would need to be added to the RO in order to define it.
 
 
 
==How to Define an Instance-Level Relation==
 
 
 
All definitions specify necessary and sufficient conditions. Thus if we are defining what it is to be an A, then the definition might read, for example:
 
 
 
x is an A =def. x has features F1, F2, F3.
 
 
 
This definition would be correct if and only if everything which has features F1, F2, and F3 is an A, and everything with an A has features F1, F2, and F3.
 
 
 
For instance-level relations, the definition might read as follows:
 
 
 
x stands in instance-level relation r to y =def. x has features F1, F2, y has features F3, F4, x stands in instance-level relations r1, r2 to y.
 
 
 
For a specific example consider:
 
 
 
:x has_duration y =def.
 
::x is a process or a processual entity, and
 
::x is continuous, and
 
::for some t, t1, t is the start of x, t1 is the end of x, y is the interval (t,t1).
 
 
 
Two new terms have been introduced: the monadic feature term '( ) is continuous' and the function term 'the interval ( , )', which generates the name of an interval from a pair of names for times. The former can be defined by introducing a new primitive relation of adjacency for occurrents. An occurrent is then continuous if and only if every proper sub-occurrent is such that there is some other proper sub-occurrent to which it is adjacent.
 
 
 
Preceded_by
 
 
 
With the primitive relations has_participant and earlier at our disposal we can define the instance-level relation p occurring_at t as follows:
 
 
 
p occurring_at t = [definition] for some c, p has_participant c at t.
 
 
 
We can then define:
 
 
 
c exists_at t = [definition] for some p, p has_participant c at t
 
 
 
p preceded_by p1 = [definition] for all t, t1, if p occurring_at t and p1 occurring_at t1, then t1 earlier t
 
 
 
t first_instant p = [definition] p occurring_at t and for all t1, if t1 earlier t, then not p occurring_at t1
 
 
 
t last_instant p = [definition] p occurring_at t and for all t1, if t earlier t1, then not p occurring_at t1
 
 
 
p immediately_preceded_by p1 = [definition] for some t, t first_instant p and t last_instant p1.
 
 
 
In light of this I propose an addition and clarification to the treatment of adjacency in the original RO paper. We now (I think) need two primitive instance-level relations:
 
 
 
*r '''adjacent_to''' r1 - a primitive relation of proximity between two spatial regions
 
 
 
*c '''adjacent_to''' c1 '''at''' t - a defined relation of proximity between two disjoint continuants (two occurrents are adjacent at t if and only if the spatial regions they occupy at t are adjacent)
 
 
 
==Proposed new relations==
 
 
 
relations between generically dependent continuants and specifically dependent continuants:
 
* concretizes
 
* is_concretized_by
 
 
 
* about
 
* inheres_in
 
* depends_on
 
* output_of
 
* has_input
 
* has_function
 
* has_quality
 
* realization_of
 
* lacks
 
 
 
The lacks family of relations is discussed at: [http://ontology.buffalo.edu/medo/NegativeFindings.pdf]
 
 
 
The treatment of the derives_from relation has been criticised from an ontological point of view: [http://www.ifomis.uni-saarland.de/Home/DerivationBookVersion1-2.pdf]. Transformation_of is always, by definition a 1-1 relation. The thesis in the original [http://genomebiology.com/2005/6/5/R46 RO paper] was (A) that the derives_from relation could be n-1 or 1-n (for n > 1) but also (B) that there are examples of 1-1 derives from relations (e.g. the relation between a living organism and a corpse). This thesis (B) has now been dropped. The relation between a corpse and the predecessor organism is one of transformation.
 
 
 
There is also the terminological problem that "derives_from" is used specifically for evolutionary relationships by some. We will report back on this after the september NCBO anatomy meeting. We may create a "develops_from" parent for transformation_of corresponding to how that relation is currently used in MOD AOs
 
 
 
See also
 
 
 
[http://obofoundry.org/ro/#pending Pending]
 
 
 
==Hunter/Bada Proposal for new relations==
 
 
 
We propose the addition of nine new relationships (and nine additional inverse relationships) to the RO.  The relationship are defined and linked to the existing relationships at [http://compbio.uchsc.edu/Hunter_lab/Bada/extended_relationship.obo]. 
 
 
 
Perhaps the most basic of these is intended to capture the idea of a process leading to a change in a continuant: <process> results_in_change_in <continuant>  (see the above linked OBO file for formal definitions).  We also propose two more specific versions of this when the continuant is either the thing changed (results_in_change_from) or the thing that results from the change (results_in_change_to). 
 
 
 
In addition, we propose well over 1000 assertions using these relationships among terms from the GO, ChEBI and CL ontologies.  In a first draft, we've identified 30 assertions in which <GO Biological Process>
 
results_in_change_in <ChEBI term>, 13 assertions in which <GO:BP> results_in_change_in <GO:CC> and 41 assertions in which <GO:BP> results_in_change_in <CL term>.  The more specific relationships are actually more prevalent: We've identified an initial 641 assertions in which <GO:BP> results_in_change_to <ChEBI term>.
 
 
 
The other relationships we propose are:
 
 
 
* results_in_capability_to_change_to
 
* results_in_directed_movement_of
 
* results_in_division_of
 
* results_in_joining_of
 
* results_in_perception_of
 
* results_in_regulation_of
 
 
 
Definitions of each and positions in the RO hierarchy are in the OBO file.
 
 
 
We've posted a message with the subject "Hunter/Bada Proposal for New Relations" on the relationship-ontology mailing list describing our rationales for these in more detail.
 
 
 
==OWL Conversion==
 
 
 
The standard GO obo->owl conversion is used. See [[OboInOwl:Main_Page]] for details
 
 
 
obo1.2 defines "builtin" tags for relations that are hardwired into the obo semantics - is_a and instance_of are tagged builtin. These are not exported in OWL, as these are also part of the OWL language
 

Latest revision as of 16:36, 1 November 2013

Announcement

OBO_REL has been replaced by RO - the new website and wiki can be found at http://purl.obolibrary.org/obo/ro

Old material that was previously kept here has been moved to RO:Historic Material