25 adult testes were dissected in PBS. DNA was isolated using phenol-chloroform method. 1ug of genomic DNA was digested by DpnI endonuclease. Digested DNA was ligated with double-stranded DNA adapters and then digested with DpnII endonuclease. Next, methylated fragments were selectively amplified using adapter-specific primer. Before the preparation of libraries for Illumina DamID-seq, the adapters used in DamID procedure were cut with DpnII enzyme. No further fragmentation was performed.