UCSC is the Data Coordination Center for the Encyclopedia of DNA Elements (ENCODE) project (11,12). This project, which aims to identify all functional elements in the human genome sequence, uses the Genome Browser as the primary data portal. ENCODE pilot phase data covering ∼1% of the human genome is available on the hg17 and hg18 (NCBI build 35 and 36) human genome browsers; genome-wide, production phase data is available on the hg18 assembly.