Figure 1: Multiplex single-cell RNA analysis can discriminate cell population heterogeneity.

(a) Conventional bulk analysis using reverse transcriptase polymerase chain reaction (RT–PCR) cannot discriminate individual cells within a population. By separating a whole population of cells into single-cell reactions, RNA levels in each cells can be determined. This can reveal subpopulations of cells based on RNA abundance. (b) Genes expressed in single cells generate mRNA abundance that follow random log-normal distributions. To be able to distinguish with a statistical power of >0.8 between different subpopulations of cells, the log-mRNA distribution for the gene of interest has to be accurately measured to correctly detect the number of normal (gaussian) components that make up the distribution. The minimum sample size required for correct subpopulation detection depends on the separation of the components (μ₂−μ₁), their s.d. σ and frequency parameter α₁. The inset shows a two-component distribution (green line) and the key parameters that characterize each Gaussian component (yellow and purple lines). Please note that the horizontal axis represents the logarithm of the mRNA abundance.