Recurrent pole-to-pole movements of the sex chromosome during prometaphase I in Melanoplus differentials spermatocytes

摘要: 1. The behavior of the X-chromosome in Melanoplus differentialis during spermatocyte prometaphase-metaphase I has been studied living and fixed material. 2. During this time X usually makes several movements from one pole to other. With few exceptions these cover whole interpolar distance without pauses or reversals direction. The kinetochore leads way pole. In a single cell path is same all pole-to-pole movements, velocity movement shows little change as prometaphase progresses. Kinetochore spindle fiber reorientation precede each trip. unpredictable feature length spent at before beginning another movement. 3. The results are considered relation congression, orientation, distribution chromosomes generally. It concluded that our present conceptions chromosome orientation cannot explain processes X-chromosome. information now available consistent with conception result forces whose direction origin those producing autosomal congression. view poleward involved congression decline prometaphase.