At the beginning of anaphase, the spindle fibers begin to pull on the cystochromatids in an attempt to separate those chromatids equally to opposite poles of the cell. Now, none disjunction takes place when the centromere holding our two chromatids fails to break or the spinal fiber actually fails to attach to one end of the chromosome. And both chromatids in that chromosome are pulled to the same side of the cell. In this case, to the left side of the cell. Now let's move on to nondisjunction taking place in meiosis. Now, meiosis is a slightly more complicated process because it actually consists of two individual stages.