What Is Score Bits In Blast?
2
5
Entering edit mode
11.5 years ago
Manju ▴ 50

i want to konw that what does it mean score and bits in local blast output from the following example?'.

Score = 38.2 bits (19), Expect = 0.11
Identities = 22/23 (95%)

Query: 1      cttaacttcagctacctcgagta 23
<br>|||||||||||||||||| ||||<br>
Sbjct: 732552 cttaacttcagctacctccagta 732574

blast scoring • 36k views
8
Entering edit mode
11.5 years ago
Nikolay Vyahhi ★ 1.3k

Also from this NCBI page:

The bit score gives an indication of how good the alignment is; the higher the score, the better the alignment. In general terms, this score is calculated from a formula that takes into account the alignment of similar or identical residues, as well as any gaps introduced to align the sequences.

0
Entering edit mode

Thank you, Nikolay, for the "obvious" answer. This is a legitimate question, of course, but could have easily been answered by Manju by simply looking at the extensive and useful help pages and other documentation provided on the NCBI pages.

1
Entering edit mode
11.5 years ago

A bit is a measure of information content. Bites, like bytes, are units of measure for digital information, in this case, with regard to the alignment and hence the similarity of the two sequences.