E-values - (Nov/04/2009 )

Hey all this is not my usual haunt but I have a question.... I have been aligning my protein sequence , trying to find a homologue in a different species. The problem is its a bit fragmented and for a portion of it i have an e-value of e-139. What does this mean?

Thanks in advance,

Kami

If I understand e-values correctly, e-values approaching zero are highly significant on long(er) sequences. Short sequences are more likely to have a greater number of matches in a database, some random, so the e-value is greater and significance is less.

Low E values indicate high degrees of similarity -- they are the expected probability that the sequences are unrelated. An E value of 1 means that the match is probably random or chance. An E value of E-139 means almost absolute certainty that these are highly related sequences.

phage434 on Nov 4 2009, 04:11 PM said: