EST Databases – dBEST & UNIGENE
dbEST
 (http://www.ncbi.nlm.nih.gov/dbEST/index.html) is a division of GenBank that contains sequence data and other information on "single-pass" cDNA sequences, or Expressed Sequence Tags, from a number of organisms.
UniGene (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=unigene) is an experimental system for automatically partitioning GenBank sequences into a non-redundant set of gene-oriented clusters. Each UniGene cluster contains sequences that represent a unique gene, as well as related information such as the tissue types in which the gene has been expressed and map location.