miRBase 19 is now available, brought to you from the Benasque RNA meeting in the sunny Pyrenees, and with a slightly larger time gap than usual. In that extended time, we have added more than the usual number of new sequences — 3171 new hairpins and 3625 novel mature products, bringing the totals to 21264 and 25141 respectively in 193 species. As always, the full README file is available on the FTP site, along with downloadable files containing all data in various formats.
We have spent some time deleting misannotated sequences, and the deep sequencing read views will allow us to focus more on this — 133 entries are removed in this release, many from the rice miRNA complement. We have also cleaned-up a number of cases of duplicate entries mapping to a single genomic locus (some prompted by new genome assembly releases) and rationalised many miRNA names. This is therefore a good time to remind you that the names are meant to be useful, but are not formally stable, and shouldn’t be used to convey complex information. The miRNA accession numbers *do* remain stable between releases, and of course, you can always quote the sequence to be truly unambiguous.
In this release, the miR* nomenclature is finally retired for all species, as previously promised. For every hairpin and mature sequence, all IDs that have previously been used in miRBase are now visible on the entry pages, and are downloadable in bulk from the FTP site.
At the time of writing, we have not added new deep sequencing datasets to the read view pages — however, a decent sized update to that section will be coming along shortly, together with an announcement here.
As always, comments, questions, abuse, praise all welcome here or by email.