How to restrict a BLAST search to a specific organism when searching NCBI

Entrez Query can be used to restrict an NCBI BLAST search to a specific organism.  To use this field, click More Options in the BLAST setup window.  

In the Entrez Query field, type in the name of the organism you want to restrict the search results to, followed by [Organism].  The screenshot below shows an example where the search results are restricted to Saccharomyces cerevisiae.  

 

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Any taxonomic level can be used with the [Organism] tag, for example you could use "Ascomycota[Organism]" to restrict the results to all Ascomycota fungi.  

Entrez queries can also be used to filter results based on other properties, such as dates, sequence length or gene properties, and multiple queries can be combined with AND, OR and NOT operators to create a more powerful filter.  See the NCBI Guide to Entrez Search for further details. 

Note that Entrez Query is only available with NCBI BLAST, and not local custom BLAST. 

 

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