The term "chromosomics is introduced to draw attention to the three-dimensional morphological changes in chromosomes that are essential elements in gene regulation. Chromosomics deals with the plasticity of chromosomes in relation to the three-dimensional positions of genes, which affect cell function in a developmental and tissue-specific manner during the cell cycle. It also deals with species-specific differences in the architecture of chromosomes, which has been overlooked in the past. Chromosomics includes research into chromatin-modification-mediated changes in the architecture of chromosomes, which may influence the functions and life spans of cells, tissues, organs and individuals. It also addresses the occurrence and prevalence of chromosomal gaps and breaks.