Question

In scoring matrices, for convenience, odds scores are converted to log odds scores.

(a) True

(b) False

I had been asked this question during a job interview.

This key question is from Use of Scoring Matrices and Gap Penalties in Sequence Alignments in portion Sequence Alignment of Bioinformatics

Answer 1

Right answer is (a) True

Easy explanation: The odds scores are converted to log odds scores so that the values for amino acid pairs in an alignment may be summed to obtain the log odds score of the alignment. In this case, the logarithms are calculated to the base 2 and multiplied by 2 to give values designated as half-bits (a bit is the unit of an odds score that has been converted to a logarithm to the base 2). The value of 4 indicates that the 4 amino acid alignment is 2(4/2) = 4 four-fold more likely than expected by chance.