A paired homologous chromosomes are called bivalents or tetrads (as one pair has four chromatids). During anaphase I, the homologous chromosomes of a bivalent separate from each other. These homologous chromosomes move to the opposite pole of the cell. Anaphasic movement of homologous chromosomes is assisted by spindle fibers. The shortening of spindle fibers pulls the homologous chromosomes to the o[opposite poles.
