blast database name in output

Question

[gb]

I wonder if anyone else had this "problem" before or have any tips for me. If I blast against multiple databases I want to know where the hit is coming from. For example:

blastn -query fasta.fa -db "database1 database2" -outfmt 6

Probably I can determine the database based on the header of the hit, but would there be a better way? Can I also assume that the sequences from genbank always start with ">gi"?

Thanks!

[GenoMax]

Can I also assume that the sequences from genbank always start with ">gi"?

No. In fact, gi numbers have been deprecated for external use (they are still used internally at NCBI).

[gb]

oh of course yes I knew that. Did not realize it because I only had ">gi" in my fasta file. Need to look up how the non gi headers look like. Thanks

[cschu181]

What happens if you use -outfmt 7? With one database it will show it in the header, not sure how it will do with two or more.

[gb]

I solved it for now by putting an "identifier" afther the >. But I will check it out.

[GenoMax]

You could include some sort of identifier in the fasta headers of the two databases (and recreate the indexes) if you want to keep them in two sets.