SRX376931 GSM1263221 SRP032967 GSE52330 SRS502341 GSM1263221 Bisulfite-Seq GENOMIC RANDOM Dentate gyri were rapidly micro-dissected bilaterally from adult mice. Genomic DNA was extracted using the DNeasy Kit (Qiagen). Three µg genomic DNA spiked-in with 0.5% unmethylated lambda DNA (Promega) from each sample was fragmented to ~ 300 bp DNA fragments using Covaris Acoustic System. The ends of fragmented DNA were repaired with T4 DNA polymerase, Klenow DNA polymerase, and T4 PNK were used to convert the overhangs into phosphorylated blunt ends. Klenow Fragment (3’ to 5’ exo minus) was used to add an ‘A’ base to the 3’ end of the blunt phosphorylated DNA fragments. Following ligation of adapters (TruSeq index, 12 indexes), bisulfite conversion was performed using an EZ DNA Methylation-Direct kit (Zymo). PCR was then used to enrich bisulfite-converted DNA fragments to obtain the DNA library suitable for HiSeq2000 sequencing. Illumina HiSeq 2000 GEO Sample GSM1263221 http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSM1263221 gds 301263221 GEO Accession GSM1263221 SRX376932 GSM1263222 SRP032967 GSE52330 SRS502347 GSM1263222 Bisulfite-Seq GENOMIC RANDOM Dentate gyri were rapidly micro-dissected bilaterally from adult mice. Genomic DNA was extracted using the DNeasy Kit (Qiagen). Three µg genomic DNA spiked-in with 0.5% unmethylated lambda DNA (Promega) from each sample was fragmented to ~ 300 bp DNA fragments using Covaris Acoustic System. The ends of fragmented DNA were repaired with T4 DNA polymerase, Klenow DNA polymerase, and T4 PNK were used to convert the overhangs into phosphorylated blunt ends. Klenow Fragment (3’ to 5’ exo minus) was used to add an ‘A’ base to the 3’ end of the blunt phosphorylated DNA fragments. Following ligation of adapters (TruSeq index, 12 indexes), bisulfite conversion was performed using an EZ DNA Methylation-Direct kit (Zymo). PCR was then used to enrich bisulfite-converted DNA fragments to obtain the DNA library suitable for HiSeq2000 sequencing. Illumina HiSeq 2000 GEO Sample GSM1263222 http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSM1263222 gds 301263222 GEO Accession GSM1263222