Blast- and LSC-enriched subpopulations were collected by FACS sorting and genomic DNA were extracted using DNA micro kit or DNA mini kit (Qiagen) Genomic DNA was digested with MspI (Fermentas), followed by end repair, adapter ligation and bisulfite modification (QIAGEN, #59104). The converted DNA library was sequenced on HiSeq 4000 (illumina) after two–round PCR amplification and size-selection