The RT primer was designed according to the Yanai protocol23 (link) with an anchored polyT, an 8 nt unique barcode, a 6 nt UMI (unique molecular identifier), the 5’ Illumina adapter (as used in the Illumina small RNA kit) and a T7 promoter. The barcodes were designed with a hamming distance of at least two between them. Primers are desalted at the lowest possible scale, stock solution 1 μg/μL. The oligo sequences can be found in Supplementary Table 3.