Electron Microscope Observations on Mitotic Chromosomes in Erythroblasts of the Newt, Triturus cristatus cristatus

THE structure of DNA is now known and the external form of mitotic chromosomes of higher organisms is fairly well characterized in the light microscope. However, the way in which chromosomes are constructed from DNA, histones and other proteins is not yet clearly understood, although there are many observations and several theories of chromosome structure 1–9 . In chromosomes of newt erythroblasts we have found structures, intermediate in size between DNA molecule and chromosome, which may provide clues to the way these chromosomes are organized.