Step #1
Paste the entires sequence into a blastx search. Search the nr database and do not specify any organism. Blastx translates DNA to protein prior to searching.
It does this six times, one for each reading frame (3 forward frames, 3 reverse frames). Only translated sequence that produces an open reading frame and
matches a database protein will be returned. Thus, only the exons in this sequence will match the database.
The best alignment is an alpha synuclein protein with 100% identity. The translated amino acids are output, but the original DNA query numbers are shown
(red circles). Note that the DNA query numbers go from 1545 to 1456. This means the exon is in opposite orientation of our query.
Step #2
The image above from step #1 indicates this is a Gallus gallus (chicken) protein.
Step #3
Copy the chicken protein sequence, NEEGFLQEGMVNNTDIPVDPENEAYEMPPE, and do a protein blast against homo sapiens. There are many hits to the human database,
either to alpha synuclein itself (AAC02114) or to one of the many variants and precursor forms of alpha synuclein.
Was it necessary to blast the chicken sequence to find the human homolog? In this case no. You discovered from step #1 that you were looking at alpha
synuclein. The name is sufficient to find the gene information. As you will learn later in the course, you can use the NCBI website or a similar human genome browser to find information on any known gene of interest.