@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix owl: <http://www.w3.org/2002/07/owl#>.
@prefix : <foo://bla#> .

:uncleOf a owl:ObjectProperty.   ### required !!!
[ ] rdfs:subPropertyOf :uncleOf;
    owl:propertyChain (:brotherOf :hasChild).

:name a owl:FunctionalProperty.
:john a :Person; :brotherOf :sue.
:sue a :Person; :hasChild :anne, :barbara.
:anne :name "Anne".   :barbara :name "Barbara".

:UncleOfMore a owl:Class; owl:equivalentClass
 [a owl:Restriction; owl:onProperty :uncleOf; owl:minCardinality 2].