title: The limits of log-ratios.
abstract: BACKGROUND
  DNA microarray assays typically compare two biological samples and present the results of those comparisons gene-by-gene as the logarithm base two of the ratio of the measured expression levels for the two samples.
  
  
  RESULTS
  Because of the fixed dynamic range of fluorescence and other detection systems, there is a limit to the range of comparisons that can be made using any array technology, and this must be taken into account when interpreting the results of any such analysis.
  
  
  CONCLUSIONS
  The dynamic range of microarray data collection systems results in limits in the comparative analyses that can be derived from such measurements and suggests that optimal results can be obtained by making measurements that avoid the boundaries of that dynamic range.
authors.affiliation: The Institute for Genomic Research, Rockville, MD, USA. vsharov@tigr.org
authors.forename: Vasily
authors.initials: V
authors.lastname: Sharov
authors.forename: Ka Yin
authors.initials: KY
authors.lastname: Kwong
authors.forename: Bryan
authors.initials: B
authors.lastname: Frank
authors.forename: Emily
authors.initials: E
authors.lastname: Chen
authors.forename: Jeremy
authors.initials: J
authors.lastname: Hasseman
authors.forename: Renee
authors.initials: R
authors.lastname: Gaspard
authors.forename: Yan
authors.initials: Y
authors.lastname: Yu
authors.forename: Ivana
authors.initials: I
authors.lastname: Yang
authors.forename: John
authors.initials: J
authors.lastname: Quackenbush
mesh_terms: D000465:Algorithms; D020869:Gene Expression Profiling / Q000379:methods / Q000592:standards*; D009693:Nucleic Acid Hybridization / Q000379:methods; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods / Q000592:standards*; D015203:Reproducibility of Results; D012984:Software