Merging blast output files

William R. Pearson wrp at alpha0.bioch.virginia.edu
Thu Apr 27 09:30:38 EST 2000


Steven Smith <ssmith at itis.com> writes:

> You do need to be careful when comparing e-values.  They take into account
> the size of the database searched.  The e-value means "I expect to find X
> hits when searching this sequence with a database of size Y." So e-values
> are comparable when Y's match.

Although "bit" scores are not so intuitive, Steve Smith's post
highlights their advantage over E()-values.  Both blast2 and fasta33
"bit" scores attempt to summarize the same information, which is
database size and query size independent.

Bill Pearson





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