Proportionality: A Valid Alternative to Correlation for Relative Data
Fig 2
Fission yeast gene expression data of Marguerat et al. (a) Absolute and (b) relative abundances of 3031 yeast mRNAs over a 16-point time course.
y-axes are scaled logarithmically; x-axes are on a square-root scale for clarity. Each grey line represents the expression levels of a particular mRNA. The red and blue pairs of mRNAs are discussed later in this paper.