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PubMed Entrez BLAST Genome Taxonomy Structure

Taxonomy Help

The NCBI taxonomy database contains only those organisms that are represented in the genetic databases with at least one protein or nucleotid sequence. The GenBank Taxonomy browser presents the classification used for the genetic database at the NCBI as an idented list. Every taxon in the list can be clicked and used to examine the taxonomic structure and to retrieve sequence data according to taxonomic criteria.

How does it work?

If you click once on any taxon in the list, the display will show only the choosen group and its subtaxa (if any). If you now click the same taxon again, the information page will be displayed. This page can provide nomenclatural and taxonomic information and it allows you to retrieve nucleotide or protein sequences for that particular group of organisms.

What does levels mean?

The browser shows by default three levels of the classification hierarchy. This number can be changed by the user by editing the "Levels" field at the top of the page and pushing the "Accept" button.

What are the little circle and squares good for?

The little circles or squares that precede the name of each taxon in the indented list do not carry any biological information. In particular, they show only taxonomy tree-related information. Square before taxon name means that it is leaf element of taxonomy tree. Circle means that taxon has children in taxonomy tree. If circle was not filled then taxon children are shown. If circle is filled it will mean that taxons' children exist but not shown on the current page. In this case You need to click on the taxon to see its children.

How to link to the NCBI taxonomy database?

Follow this link to figure it out.
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Credits: Scott Federhen, Ian Harrison, Carol Hotton, Detlef Leipe, Vladimir Soussov, Richard Sternberg, Sean Turner.
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