It is now widely recognized that the packaging of genomic DNA together with core histones, linker histones, and other functional proteins into chromatin profoundly influences nuclear processes such as transcription, replication, repair and recombination. How chromatin structure modulates the expression and maintenance of knowledge encoded in eukaryotic genomes, and how these processes take place within the context of a highly complex and compacted genomic chromatin environment remains a major unresolved question in biology. Here we review recent advances in our understanding of how nucleosome and chromatin structure may have to adapt to promote these vital functions.