Linear models for Microarray analysis

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Revision as of 04:34, 14 March 2006 by Sven (talk | contribs) (Origin)
Overview of Limma package for R
  • Fits a linear model for each spot (gene)
  • An open source software package for the R programming environment
  • Focus on normalization and statistical analysis of cDNA microarray gene expression data
  • OOP environment for handling information in a microarray experiment
  • Statistical analysis approach can be used for Affymetrix microarray experiments

Origin
  • Written and maintained by Gordon Smyth with contributions From WEHI, Melbourne, Australia
  • Software made public at the Australian Genstat Conference, Perth, in Dec 2002
  • Became available in the Bioconductor open source bioinformatics project April 2003
  • Limma integrates with other Bioconductor software packages, affy, marray, using convert package
  • Active development cycle

File:Limma versions.tiff


Object orintated programming environment

File:OOP.tiff


Scratchpad

  • Essentially t-statistics for each spot/gene
  • Uses between gene information in moderated t-statistics
  • Computationally fast/robust
  • Handles missing information/use defined flag information
  • benefits/limitations?
  • FDR control? → ranking better than selecting cutoff