The disomal series generated by the digestion of chromatin with DNase I has been followed to its highest orders using Klenow end-labelling and field-inversion gel electrophoresis to maximise the resolution of large DNA fragments. The series is coherent to the 16N level and as such is incompatible with the most structurally acceptable coiling models. We propose that this is evidence for the general unsuitability of coiling models and is support for the existence of simple “back-to-back” double-stranded structures within chromatin.
