This illustration demonstrates how to use BLASTN to search starting with a nucleotide sequence.
You can start from the NCBI BLAST home page: http://blast.ncbi.nlm.nih.gov/Blast.cgi
Or, you can start from a Nucleotide record. In this case, we start from the RefSeq mRNA link within the LCT Gene record:
Click on the NM_002290.2 record ID in order to display the Nucleotide record:
To search BLASTN using the mRNA RefSeq:
Or, from the Nucleotide record, find the base pair (bp) sequence:
Click on the CDS link to highlight the base sequence:
Grab the sequence and then cut&paste into the BLASTN search box:
In either case, you can use the default databse Nucleotide Collection (nr/nt) for the widest search and then click BLAST to run the search:
The following is the top of the resulting nucleotide BLASTN search:
Analysis of the rest of the BLASTN results are discussed in the BLAST Results page: View BLAST Results
