library_construction_protocol: Organoids differentiation from hESC cell lines were harvested at days 35, 96 and 152 of retinal differentiation, frozen and stored at -80°C until use.  RNA of single organoids was prepared using the Monarch Total RNA miniprep kit (NEB). Equal amounts of RNA of three organoids per time point per differentiation experiment was pooled. Production of strand-specific mRNA libraries with TruSeq Stranded mRNA kit, Illumina; done by CeGaT, Tübingen, Germany