NCBI expect value

Question

[genomics Newbie]

If an NCBI sequence match has an e (expect) value of 5e-128 there is little or no chance that your sequence is by chance, correct? My understanding is that if you have an NCBI E (expect) value of 0 then you can expect to see 0 BLAST hits by chance. Therefore, 5e-128 (-114) would presume that the BLAST hit is highly significant and probably not due to chance, correct?

Thank you.

[Andrzej Zielezinski]

Agree! See also: What Is The Lowest E-Value In Blast When Ncbi Rounds It Down To 0 (Zero)

[GenoMax]

That is correct.