x has prototype y if and only if x is an instance of C and y is a prototypical instance of C. For example, every instance of heart, both normal and abnormal is related by the has prototype relation to some instance of a "canonical" heart, which participates in blood circulation.
This property can be used to make weaker forms of certain relations by chaining an additional property. For example, we may say: retina SubClassOf has_prototype some 'detection of light'. i.e. every retina is related to a prototypical retina instance which is detecting some light. Note that this is very similar to 'capable of', but this relation affords a wider flexibility. E.g. we can make a relation between continuants.
Experimental. In future there may be a formalization in which this relation is treated as a shortcut to some modal logic axiom. We may decide to obsolete this and adopt a more specific evolutionary relationship (e.g. evolved from)