[Bioclusters] Re: Help on BLAST

Lai Loong Fong bioclusters@bioinformatics.org
Wed, 28 Aug 2002 09:22:05 +0800


At 11:18 AM 27/8/2002 +0200, you wrote:
>Hi Chris,
>
> >
> >
> > Wim,
> >
> > If you assume that the two blast target sets are non-overlapping, the
> > only scores which need to be recalculated are the e- and p- values.
> > Score and Bit Score are based soley on the alignment, substitution
> > matrix, and gap costs, plus the K and lambda parameters.  Those don't
> > change with target set size.
> >
> >   e-value = { m n 2^(bit_score) }
>
>Shouldn't this be:
>
>         e-value = { m n 2^(-bit_score) }
>
>I think you forgot a minus. This is the equation found in the blast
>tutorial.
Hi Wim,
May I know which blast tutorial are you referring to here?

Lai L F