bioperl 1.6.9 version is installed in my system.. its not the reason bcs blast is working fine when i am blasting with follwing code.. #!usr/bin/perl -w use Bio::Perl; $seq = get_sequence('NCBI',"NM_181451"); $blast_result=blast_sequence($seq); write_blast(">xyz.blast",$blast_result); Manju