hello, I am experiencing a strange behaviour of blastn with the option "evalue":
$ blastn -task blastn -query _p -db genome.fa -outfmt 6
snoRNA_CD33 Chromosome_5 76.85 108 19 5 4 109 2773492 2773389 4e-11 66.2
snoRNA_CD33 Chromosome_2 91.30 23 1 1 45 66 7139854 7139876 2.9 30.1
snoRNA_CD33 Chromosome_1 94.74 19 1 0 28 46 3318593 3318575 2.9 30.1
good, found a hit at 4e-11 evalue
$ blastn -task blastn -query _p -db genome.fa -outfmt 6 -evalue 1
snoRNA_CD33 Chromosome_5 76.85 108 19 5 4 109 2773492 2773389 4e-11 66.2
same hit setting the evalue threshold at 1, as expected
$ blastn -task blastn -query _p -db genome.fa -outfmt 6 -evalue 0.1
$
no result! why? 4e-11 is still less than 0.1....
any idea?
$ blastn -task blastn -query _p -db genome.fa -outfmt 6
snoRNA_CD33 Chromosome_5 76.85 108 19 5 4 109 2773492 2773389 4e-11 66.2
snoRNA_CD33 Chromosome_2 91.30 23 1 1 45 66 7139854 7139876 2.9 30.1
snoRNA_CD33 Chromosome_1 94.74 19 1 0 28 46 3318593 3318575 2.9 30.1
good, found a hit at 4e-11 evalue
$ blastn -task blastn -query _p -db genome.fa -outfmt 6 -evalue 1
snoRNA_CD33 Chromosome_5 76.85 108 19 5 4 109 2773492 2773389 4e-11 66.2
same hit setting the evalue threshold at 1, as expected
$ blastn -task blastn -query _p -db genome.fa -outfmt 6 -evalue 0.1
$
no result! why? 4e-11 is still less than 0.1....
any idea?
Comment