JASPAR is a popular open-access database for matrix models describing 
DNA-binding preferences for transcription factors and other DNA patterns. With 
its third major release, JASPAR has been expanded and equipped with additional 
functions aimed at both casual and power users. The heart of the JASPAR 
database-the JASPAR CORE sub-database-has increased by 12% in size, and three 
new specialized sub-databases have been added. New functions include clustering 
of matrix models by similarity, generation of random matrices by sampling from 
selected sets of existing models and a language-independent Web Service 
applications programming interface for matrix retrieval. JASPAR is available at 
http://jaspar.genereg.net.