library_construction_protocol: After collagenase-assisted tissue dissociation, single-cell suspensions were converted into individually barcoded cDNA libraries with the Chromium Single Cell 3′ Library & Gel Bead Kit v2 from 10X Genomics. All 3 libraries were sequenced on a 2x150nt lane in a HiSeq 4000; Reads are 26nt (read1) and 98nt (read2) nt in length.