title: Compression of next-generation sequencing quality scores using memetic algorithm.
abstract: BACKGROUND
  The exponential growth of next-generation sequencing (NGS) derived DNA data poses great challenges to data storage and transmission. Although many compression algorithms have been proposed for DNA reads in NGS data, few methods are designed specifically to handle the quality scores.
  
  
  RESULTS
  In this paper we present a memetic algorithm (MA) based NGS quality score data compressor, namely MMQSC. The algorithm extracts raw quality score sequences from FASTQ formatted files, and designs compression codebook using MA based multimodal optimization. The input data is then compressed in a substitutional manner. Experimental results on five representative NGS data sets show that MMQSC obtains higher compression ratio than the other state-of-the-art methods. Particularly, MMQSC is a lossless reference-free compression algorithm, yet obtains an average compression ratio of 22.82% on the experimental data sets.
  
  
  CONCLUSIONS
  The proposed MMQSC compresses NGS quality score data effectively. It can be utilized to improve the overall compression ratio on FASTQ formatted files.
authors.forename: Jiarui
authors.initials: J
authors.lastname: Zhou
authors.forename: Zhen
authors.initials: Z
authors.lastname: Ji
authors.forename: Zexuan
authors.initials: Z
authors.lastname: Zhu
authors.forename: Shan
authors.initials: S
authors.lastname: He
mesh_terms: D000465:Algorithms; D044962:Data Compression / Q000379:methods*; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods*; D017422:Sequence Analysis, DNA / Q000379:methods*