library_construction_protocol: We used 18 amplification cycles, and the cells were split up in 5 cDNA synthesis batches with 16-36 cells per round. cDNA was purified after amplification using Agencourt AMPure XP beads (Beckman Coulter #A63880). The DNA libraries were prepared using the Nextera XT DNA Library Preparation Kit (Illumina # FC-131-1024).