I blasted a serires of inquiry sequences against the a pre-built blast-database file using blastall and the xml result was parsed by biopython.
I got the genomic coordinates information of the inquiry sequences.
Now I also want to know the 500bp sequences upstream and downstream of each inquiry sequences.
I know biopython can achieve this by extracting sequences from fasta file of each chromosome or from online database.
But I don't want to do this because I don't have enough spaces to keep fasta file of each chromosome locally. And online fetching is too slow when the inquiry file is large.
Is that possible to fetch such sequences using genomic coordinates from the pre-built blast-database file (So I can just keep this database file on the disk for each species)?