It was originally constructed as a collection of uniquely determined transcriptional start sites (TSSs) in humans and some other species in 2002. Since then, DBTSS has been regularly updated and in recent updates epigenetic information has also been incorporated because such information is useful for characterizing the biological relevance of these TSSs/downstream genes. DBTSS is no longer a mere storage site for TSS information but has evolved into an integrative platform of a variety of genome activity data.