The fine structure of wet human chromosome/chromatin neither fixed nor stained wasstudied by atomic force microscopy (AFM) in comparison with soft X-ray contact microscopy (XCRM). Fibers with typical knobby appearance and particles of 30-60 nm in diameter within and around the fibers were evidently observed by AFM. Globular clusters of nucleosomes ('moluroid' organization of nucleosomes, superbeads) were observed by XCRM in the specimens prepared in the same way.
Both data suggested that chromatin fibers are basically composed of various sizes of condensed particles.