Replication of chromosomes is one of the central events in the cell cycle. 
Chromosome replication begins at specific sites, called origins of replication 
(oriCs), for all three domains of life. However, the origins of replication 
still remain unknown in a considerably large number of bacterial and archaeal 
genomes completely sequenced so far. The availability of increasing complete 
bacterial and archaeal genomes has created challenges and opportunities for 
identification of their oriCs in silico, as well as in vivo. Based on the 
Z-curve theory, we have developed a web-based system Ori-Finder to predict oriCs 
in bacterial genomes with high accuracy and reliability by taking advantage of 
comparative genomics, and the predicted oriC regions have been organized into an 
online database DoriC, which is publicly available at 
http://tubic.tju.edu.cn/doric/ since 2007. Five years after we constructed 
DoriC, the database has significant advances over the number of bacterial 
genomes, increasing about 4-fold. Additionally, oriC regions in archaeal genomes 
identified by in vivo experiments, as well as in silico analyses, have also been 
added to the database. Consequently, the latest release of DoriC contains oriCs 
for >1500 bacterial genomes and 81 archaeal genomes, respectively.