Studies of Mitosis and Meiosis in Comparison

II. Chromosome structure in the spiral stage and anaphase in mitosis as revealed by means of a maceration method

Abstract

Some fine structures of chromosomes which are not rendered visible by other methods, are shown to exist in the preparations made by the maceration method used in the present investigation.
Each anaphase chromosome is composed of two chromatids (half-chromosomes) each of which contains a chromonema spiral or spirals. The two chromatids may twist around each other to a greater or less degree. During telophase and interphase the chromonema remains in the coiled state, although the coiling is renderec somewhat irregular. At the commencement of prophase the chro. monemata of each individual chromosome seem to draw close together. In the following stage the chromonema spirals are converted to regularly coiled major spirals in which the new or minor coiling is in progress, as the result of which the prophasic chromosome changes, such as the straightening out of the old spirals, and the thickening and shortening of the chromosome, take place. Gradually each chromosome develops a visible longitudinal split.