CAS indexing practices change over time in response to scientific developments. In the 1990s, with the rapid advance of biotechnology and the "Genomic Revolution," CAS began to register not only sequences we encountered in the process of analyzing journal literature and patents but also all sequences added to GenBank®, even those not reported in the literature. CAS revised its coverage policy in 2005. From that point, CAS (1) limited the registration of GenBank sequences to those reported in the journal literature or patents and (2) stopped adding to CAS REGISTRYSM any sequences from patents that contained more than approximately 4,000 sequences. In 2007, CAS stopped adding to CAS REGISTRY GenBank sequences in journal articles that referenced more than 500 GenBank accession numbers.
For additional information on sequences, see: