Nuclear Size in Relation to Meiosis

1. Prophase mitotic nuclei are 1.44 times greater in volume than resting mitotic nuclei, while prophase meiotic nuclei are 3.52 times greater in volume than resting meiotic nuclei; and meiotic prophase nuclei are 3.25 times greater in volume than mitotic prophase nuclei. 2. Apparently the increase in meiotic nuclear size is accompanied by a decrease in viscosity of karyolymph, which results in extremely liquid karyolymph at the zygonema stage. 3. The time required for meiosis is much longer than that required for mitosis. 4. A hypothesis is advanced that the increase in volume of meiotic prophase nuclei, the decrease in viscosity of the karyolymph, and the comparatively long duration of meiosis, operate harmoniously to allow intimate gene by gene association of homologous chromosomes in the first prophase of meiosis.