NCBI

Starting with ...

A GENE NAME, PRODUCT NAME, OR SYMBOL

1. Search the Gene database with the gene name, product name, or symbol. If you know the gene symbol and species, enter them as follows: tpo[sym] AND human[orgn]
2. Click on the desired gene.
3. Click on "Reference Sequences" in the Table of Contents at the upper right of the gene record.
4. The NCBI Reference Sequences section of the record has links to NCBI curated records for the genomic region, transcripts, and proteins for the gene of interest for eukaryotic organisms. Transcript sequences are not produced for prokaryotes.

A SEQUENCE ACCESSION NUMBER (e.g. U00001, AAA60471)

1. Perform an All databases search with the accession number.
2. Click on the result for the relevant database (Nucleotide, EST, GSS, Protein).
3. Look for the "Reference sequence information" section on the right-hand-side of the sequence record and follow the link(s) to the corresponding reference sequences.
4. The "More about the ... gene" section, when present, leads to the corresponding gene record. The gene record may provide access to additional reference sequences.

A NUCLEOTIDE OR PROTEIN SEQUENCE

1. Use the NCBI BLAST service to perform a similarity search.
2. Select the appropriate blast link from the Basic BLAST section of the BLAST home page. Use the table below to select the correct BLAST form and database. The translating services are not needed since the protein reference sequence is accessible from the corresponding nucleotide record, and the nucleotide is accessible from the protein.

   Program	Query Sequence	Desired Reference Sequence type	Database
   nucleotide blast	nucleotide	mRNA	Reference mRNA
   nucleotide blast	nucleotide	genomic	Reference genomic
   protein blast	protein	protein	Reference protein

3. Click the "BLAST" button to run the search and identify matching sequences.