Fig. 2

Flow chart of droplet-based single cell RNA sequencing. In the Drop-seq, one channel contains single cells for analysis and the other contains microparticle beads. The surface of a microparticle bead binds oligonucleotides that consist of oligo dT (green), a unique molecular identifier (UMI; red), a cell barcode (blue), and a PCR primer (brown). Immediately after droplet formation, cells are lysed and mRNAs released and then hybridized with oligonucleotides on the surface of the microparticle beads based on oligo dT binding. Droplets are then broken and mRNAs are reverse-transcribed in bulk and amplified for sequencing using PCR. Moreover, in the 10× Genomics platform, one channel contains single cells for analysis and the other contains gel beads mixed with oligonucleotides that consist of oligo dT, UMI, cell barcode, and a PCR primer. Cells and reagents are next mixed with gel beads. After cell lysis, their mRNAs are released and hybridized with oligonucleotides based on oligo dT binding, and are next reverse-transcribed in bulk and amplified for sequencing using PCR. P1 and P2 are PCR primers for establishing libraries for Illumina sequencing