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NCBI Resources: Gene

Contains information about the NCBI databases to be used as a teaching tool.

Boolean Operators

Boolean operators allow you to combine search terms: 

  • AND: Finds documents that contain both terms.
  • OR: Finds documents that contain either term. 
  • NOT: Finds documents that contain the term on the left but not the term on the right.

Advanced Search

By default, Entrez searches your text in "All fields", which looks for the text anywhere in the entry. So if you're getting irrelevant results, try limiting your text to a particular field.

Don't know what fields you can search for? Use the Advanced search

1. Click on advanced beneath the search bar. 

2. Click the drop down menu under Builder to see what fields are stored in gene records.

This is a comprehensive list of all fields you can search for. Fields will vary by database. Example shown here is for the Gene database. 

Need help? Ask Wlad

Searching Gene

You can search the Gene database by

  • Free text: schizophrenia - any gene with the word schizophrenia anywhere in the record
  • Chromosomal location: 6[Chr] - all genes on chromosome 6 of any organism
  • Organism: human[Organism] - all genes in humans
  • Gene symbol: apoe[sym] - all genes called apoe in any organism
  • Genes with medical relevance-  "gene medgen diseases"[filter] - all gene records with links to MedGen 

These search terms can be combined using Boolean operators. A common search strategy is to search for a gene symbol in an organism:

apoe[sym] AND human[orgn]

Will retrieve the record for the human APOE gene. Typically, this type of search will bring up a single record, because gene symbols are unique. 

You could also search for human genes with clinically relevant SNPs on chromosome 6

gene_snp_clin[filter] AND human[orgn] AND 6[chr]

Get creative with the search terms depending on what type of information you want to find. 


Gene Search Results

After submitting your search, a list of results will appear with gene records that match your query. The results page is divided into 3 columns:

  1. Filters: more ways to limit your search by things like genome location
  2. Results: a list of the Gene records that match your query with basic information
  3. Discovery Column: links to other databases and Search details

Search details shows you what Entrez searched for. Typically you will see alive[prop] appended to your searches to only query up to date records, excluding those that have been retired. 

Gene Records

Each gene record contains an immense amount of information. See below for a summary of what is in each section. See the pages for each section for more information (coming soon).