A schematic representation of the mouse Ppar-α gene organization. The mouse Ppar-α gene is located on chromosome 15 and contains eight exons. Based on the characterization of the human Ppar-α gene reported by Pineda Torra (2002) [23], we selected three different fragments of the gene rich in CG dinucleotides within the proximal promoter, 5′-UTR (within exon 1), or 3′UTR portions of the gene and amplified by specific primers using the qPCR technique. The selected region (region 1) consists of a CpG-enriched promoter fragment positioned at −50/+31 bp linking the 5′-upstream promoter region to the 5′-UTR fragment of Exon 1. Region 2 amplified the 5′-UTR and part of exon 1 after the transcription starting nucleotide (+1) positioned at +9 +149 bp, whereas region 3 covered the 3′-UTR and part of the exon 8 positioned at +1715 +1813 bp. The increase in cytosine methylation levels was measured by methylated DNA immunoprecipitation (MeDIP) of the Ppar-α gene fragments (region 1: unpaired t test: * p = 0.04, t = 2.23, df = 14, n = 8; region 2: * p = 0.03; t = 2.30; df = 14; n = 8; region 3: * p = 0.02; t = 2.59; df = 14; n = 8). In addition, a positive correlation between methylated cytosines (mC) levels of region 2 and aggressive behavior was observed (Pearson’s r = 0.70; * p = 0.02; n = 8).