DE D N, KAUFMANN B P
J Biophys Biochem Cytol. 1956 Jul 25;2(4 Suppl):419-24. doi: 10.1083/jcb.2.4.419.
Electron micrographs of staminate hair cells of Tradescantia reflexa indicate that early prophase chromosomes are composed of a number of helically arranged chromonemata. Favorable preparations reveal as many as 64 identifiable subsidiary strands, assumedly arranged as intertwined pairs to form a hierarchy of pairs of pairs. The helices of the smallest discernible units have a diameter of about 125 A, with highly electron-scattering material disposed peripherally around a less dense "core." The wall of this peripheral ring has a thickness of about 40 A, and apparently represents another pair of coiled threads surrounding a 40 A central axis. The implications of the findings are discussed briefly.