AT-rich regions have been shown to be excluded from nucleosomes and while the core
nucleosome DNA is typically GC-rich, a CG(9) repeat capable ofadopting a Z-DNA structure was excluded from nucleosomes in S. cerevisiae [141]. Further, CpG repeats in the promoter region of the chicken adult beta-globin gene, capable of forming Z-DNA, were not able to bind to the histone octamer in vitro .