What is the primary event that characterizes Anaphase I in meiosis?

The primary event that occurs during Anaphase I of meiosis is the separation of homologous chromosomes, which move to opposite poles of the cell. This process is crucial because it reduces the chromosome number by half, ensuring that each daughter cell will receive only one chromosome from each homologous pair.

During Anaphase I, the spindle fibers tug on the homologous chromosomes that have already been paired during the previous phase, Prophase I. As a result, these chromosomes, each consisting of two sister chromatids, are pulled to opposite sides. This separation differs from Anaphase II, which involves the separation of sister chromatids.

Understanding this distinction is important in genetics and biology, as the reduction in chromosome number during meiosis is fundamental to the formation of gametes and contributes to genetic diversity in sexually reproducing organisms.