title: Structural options.
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002843:Chromatin / Q000648:ultrastructure*; D006657:Histones / Q000235:genetics*; D009154:Mutation; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013698:Templates, Genetic
chemical_list: D002843:Chromatin; D006657:Histones