Alu sequences carry periodical pattern with CG dinucleotides (CpG) repeating every 31-32 bases. Similar distances are observed in distribution of DNA curvature in crystallized nucleosomes, at positions ±1.5 and ±4.5 periods of DNA from nucleosome DNA dyad. Since CG elements are also found to impart to nucleosomes higher stability when positioned at ±1.5 sites, it suggests that CG dinucleotides may play a role in modulation of the nucleosome strength when the CG elements are methylated. Thus, Alu sequences may harbor special epigenetic nucleosomes with methylation-dependent regulatory functions. Nucleosome DNA sequence probe is suggested to detect locations of such regulatory nucleosomes in the sequences.