Question

Which of the following is incorrect about Phred?

(a) It is a UNIX program

(b) It doesn’t give a probability score in output

(c) It is used for base calling

(d) It uses a Fourier analysis to resolve fluorescence traces and predict actual peak locations of bases

I got this question in an interview for internship.

Question is from Genome Sequence Assembly topic in section Genome Mapping, Assembly and Comparison of Bioinformatics

Answer 1

The correct choice is (b) It doesn’t give a probability score in output

The explanation is: It also gives a probability score for each base call that may be attributable to error. The commonly accepted score threshold is twenty, which corresponds to a 1% chance of error. The higher the score, the better the quality of the sequence reads. If the score value falls below the threshold, human intervention is required.