Bioinformatics Advance Access published online on February 23, 2008
Bioinformatics, doi:10.1093/bioinformatics/btn052
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The effect of sequence quality on sequence alignment
Institute of Marine Research, Bergen, Norway
To whom correspondence should be addressed.Dr. Ketil Malde, E-mail: ketil.malde{at}imr.no
| Abstract |
|---|
Motivation: The nucleotide sequencing process produces not only the sequence of nucleotides, but also associated quality values. Quality values provide valuable information, but are primarily used only for trimming sequences and generally ignored in subsequent analyses.
Results: This paper describes how the scoring schemes of standard alignment algorithms can be modified to take into account quality values to produce improved alignments and statistically more accurate scores. A prototype implementation is also provided, and used to post-process a set of BLAST results. Quality-adjusted alignment is a natural extension of standard alignment methods, and can be implemented with only a small constant factor performance penalty. The method can also be applied to related methods including heuristic search algorithms like BLAST and FASTA.
Availability: http://malde.org/~ketil/qaa.
Contact: ketil.malde{at}imr.no
Associate Editor: Dr.Limsoon Wong
Received on September 13, 2007; revised on February 1, 2008; accepted on February 1, 2008