Extended Data Figure 7.

ERCC sequence abundances followed a highly linear trend in all pairs of samples across at least 5 orders of magnitude. The absolute abundance of mRNA transcripts was estimated using the ERCC92 RNA spike-ins³². Sequencing reads were aligned to the 92 reference spike-in sequences and the abundance of these sequences between different samples was compared. ERCC sequence abundances followed a highly linear trend in all pairs of samples across at least 5 orders of magnitude (Pearson correlation coefficient larger than 99.7%). Diagonal entries in the figure matrix show the density of read counts. ERCC RNAs are consistently detected at higher abundance in the paused state compared to serum and 2i.