Thread: BLAST result
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Old 04-28-2011, 10:22 AM   #1
rdu
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Location: USA

Join Date: Aug 2010
Posts: 29
Default BLAST result

Hi,

Greetings!

Anyone happened to know the tricks by using 'Effective Search Space' (ESS) in the BLAST result to get the E-value.

I just simply tried the Karlin-Altschul Statistics:
E=K*ESS*exp(-lambda*S),
but couldn't get the exact number with it shown by BLAST.

For example, k=0.041, ESS=1499375124, lambda=0.267, S=63, then I got 3.04, but it's 3.4 from BLAST. Do I need provide any other database information?

I'm using BLASTX 2.2.23+. Thanks in advance.
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