title: A back-to-back zig-zag model for higher order chromatin structure.
abstract: The evidence for the next level of chromatin structure above the 'zig-zag' is examined and a system of large, uncoiled, 'hair-pin' loops, folded until the zig-zags are back to back, is proposed as being more compatible with the evidence than coiling models. The loop model suggests a simple way for the base sequences on the DNA to control the higher order folding of chromatin, and is also strongly suggestive of a simple mechanism ensuring homologous alignment of nucleofilaments at synapse.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002843:Chromatin / Q000648:ultrastructure; D004247:DNA; D006801:Humans; D008854:Microscopy, Electron; D008958:Models, Molecular; D009707:Nucleosomes / Q000648:ultrastructure; D011487:Protein Conformation
chemical_list: D002843:Chromatin; D009707:Nucleosomes; D004247:DNA