Expanded average nucleotide identity analysis now available for prokaryotic genome assemblies

As we described in an earlier post, GenBank uses average nucleotide identity (ANI) analysis to find and correct misidentified prokaryotic genome assemblies. You can now access ANI data for the more than 600,000 GenBank bacterial and archaeal genome assemblies through a downloadable report (ANI_report_prokaryotes.txt) available from the genomes/ASSEMBLY_REPORTS area of the FTP site. The README describes the contents of the report in detail. You can use the ANI data to evaluate the taxonomic identity of genome assemblies of interest for yourself.

The new ANI_report_prokaryotes.txt replaces the older ANI_report_bacteria.txt in the same directory. We are no longer updating the ANI_report_bacteria.txt file and will remove it after 31st May 2020.

Improving the Display of Type Material in the NCBI TaxBrowser

Have you ever been confused by multiple taxonomic names for a single organism? You’re not alone! It’s one of the challenges in maintaining any biological database. Recently we updated the NCBI TaxBrowser to assist with this.

Let’s start with a brief word about how investigators name species in the first place. For any new species, the reporting author declares a “type.” They then deposit a specimen, or “type material,” in a publicly available biorepository. This type material is tied to the new species name and serves as a reference for future comparisons. Researchers can then use DNA sequences obtained from type material to identify other samples from the same species. NCBI currently uses such an approach to verify the taxonomic assignment of prokaryotic genomes.

Our Taxonomy group has been curating type material records in the Taxonomy database since 2013 using a common vocabulary accepted by our international partners (the INSDC). For example, the Entrez query “type material[prop]” in the Taxonomy database will return all type material at NCBI.

So what are the improvements to the TaxBrowser?

Continue reading

May 16 webinar: Improved Standalone BLAST database and programs: now with taxonomic information

Next Wednesday, May 16, 2018, we’ll show you how to download and use the latest standalone BLAST databases, dbv5. You’ll learn how to use BLASTdbv5 and the new BLAST programs to limit searches to taxonomic groups and to retrieve sequences from the database by taxonomy.

Date and time: Wed, May 16, 2018 12:00 PM – 12:30 PM EDT

Register here: https://bit.ly/2qW7LLy

After registering, you will receive a confirmation email with information about attending the webinar. A few days after the live presentation, you can view the recording on the NCBI YouTube channel. You can learn about future webinars on the Webinars and Courses page.

BLAST+ database improved

We’ve made some recent enhancements to the BLAST+ applications that allow you to:

  1. Limit your search by taxonomy using information built into the BLAST databases
  2. Search sequences by accession faster
  3. Use blastdbcmd to retrieve sequences by taxonomy from a BLAST database

The new version of the BLAST databases (version 5, release notes) supports the items listed above. You can access the new executables on FTP. Sample version 5 databases are also available.

Note: This is an alpha release to allow users to test and comment on new features.

Problems/Feedback

Please send problem reports and feedback to blast-help@ncbi.nlm.nih.gov or write to the Help Desk.

New taxonomy files available with lineage, type, and host information

NCBI is now producing a new set of taxonomy files that include the taxonomic lineage of taxa, information on type strains and material, and host information. These files are particularly helpful for people maintaining local installations of NCBI data.

You can download the new archive (new_taxdump.tar.gz) from the taxonomy directory on the FTP site (ftp.ncbi.nlm.nih.gov/pub/taxonomy/new_taxdump/). The new files are typematerial.dmp, typeoftype.dmp, rankedlineage.dmp, fullnamelineage.dmp,
taxidlineage.dmp, and host.dmp. Please see the readme file for details of the file contents.

The original taxonomy file archive without the new content will remain available under its original name, taxdump.tar.gz. The section below shows the entries for the monkey species Cercopithecus lomamiensis from the new ranked lineage and  type material files. Continue reading