EST projects have their roots in the early 1980s, when it was recognized that short stretches of DNA sequences from cDNAs could be used to identify genes. The Institute for Genomic Research (TIGR) was established to generate EST data on a massive scale. Among the largest projects conducted entirely in the public domain include an effort funded by Merck and Co., which has deposited more than 500,000 human ESTs into dbEST. A hallmark of these endeavours, carried out by a collaboration between Washington University Genome Sequencing Center and members of IMAGE (Integrated Molecular Analysis of Gene Expression) consortium, has been the rapid deposition of the sequences into the public domain and the concomitant availability of the sequence-tagged clones.