| Correlations between relative abundances tell us absolutely nothing | We stress in the absence of any other information or assumptions to highlight the common assumption of constant absolute abundance of total mRNA across all experimental conditions. |
| Correlations between relative abundances tell us absolutely nothing | If this assumption holds, and all the mRNAs comprising that total are considered, the relative abundance of each kind of mRNA will be proportional to its absolute abundance, and analyses of correlation or “differential expression” of the relative values will have clear interpretations. |
| Correlations between relative abundances tell us absolutely nothing | Consider the red mRNA pair in Fig. |
| Proportionality is meaningful for relative data | We calculated gb for the relative abundances of all pairs of mRNAs and compared it to the correlations between their absolute abundances (S4 Fig): clearly, the absolute abundances of most mRNA pairs are strongly positively correlated; far fewer are also strongly proportional. |
| Results | Data on absolute mRNA abundance |
| Results | [6] on the absolute levels of gene expression (i.e., mRNA copies per cell) in fission yeast after cells were deprived of a key nutrient (Fig. |
| Results | Unlike many experiments where researchers ensure (or assume) cells produce similar amounts of mRNA across conditions [7] , this experiment ensured cells produced very different amounts so as to illustrate the merits of absolute quantification (81 F ig. |