title: Efficient statistical significance approximation for local similarity analysis of high-throughput time series data.
abstract: BACKGROUND
  Local similarity analysis of biological time series data helps elucidate the varying dynamics of biological systems. However, its applications to large scale high-throughput data are limited by slow permutation procedures for statistical significance evaluation.
  
  
  RESULTS
  We developed a theoretical approach to approximate the statistical significance of local similarity analysis based on the approximate tail distribution of the maximum partial sum of independent identically distributed (i.i.d.) random variables. Simulations show that the derived formula approximates the tail distribution reasonably well (starting at time points > 10 with no delay and > 20 with delay) and provides P-values comparable with those from permutations. The new approach enables efficient calculation of statistical significance for pairwise local similarity analysis, making possible all-to-all local association studies otherwise prohibitive. As a demonstration, local similarity analysis of human microbiome time series shows that core operational taxonomic units (OTUs) are highly synergetic and some of the associations are body-site specific across samples.
  
  
  BACKGROUND
  The new approach is implemented in our eLSA package, which now provides pipelines for faster local similarity analysis of time series data. The tool is freely available from eLSA's website: http://meta.usc.edu/softs/lsa.
  
  
  BACKGROUND
  Supplementary data are available at Bioinformatics online.
  
  
  BACKGROUND
  fsun@usc.edu.
authors.affiliation: Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-2910, USA.
authors.forename: Li C
authors.initials: LC
authors.lastname: Xia
authors.forename: Dongmei
authors.initials: D
authors.lastname: Ai
authors.forename: Jacob
authors.initials: J
authors.lastname: Cram
authors.forename: Jed A
authors.initials: JA
authors.lastname: Fuhrman
authors.forename: Fengzhu
authors.initials: F
authors.lastname: Sun
mesh_terms: D005260:Female; D020869:Gene Expression Profiling; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D008297:Male; D008390:Markov Chains; D054892:Metagenome; D015233:Models, Statistical; D012984:Software