The generation of complex organisms requires that an initial population of cells with
identical gene expression profiles can adopt different cell fates during development by
progressively diverging transcriptional programs. These programs depend on the binding of
transcritional regulators to specific genomic sites, which in turn is controlled by modifications
of the chromatin. Chromatin modifications may occur directly upon DNA by methylation of
specific nucleotides, or may involve post-translational modification of histones. Local …