Question about ontology query languages... (please reply!!!)

Hello,
I'm a phd student in Information Technology at the 
University of Camerino (Italy).
I would like to know if it's possible to do recursive 
queries in SPARQL.
In fact I've this problem. I've an ontology in OWL with 
only relations is-a. This ontology is made like a tree. I 
would like to select a subgraph made of the path from the 
leaf node to the root node (result example: A(leaf) is-a B 
is-a C is-a D(root)).
How could I do this using only a single query? Shoud I do 
this with SPARQL? If not, do You know another ontology 
query language to do this?

Please reply.
Thanks.
Regards.
Cristina Lancioni.