Independent assortment occurs during meiosis, specifically at metaphase I of meiotic division. At this stage, homologous chromosomes line up randomly in the center of the cell, and their orientation is independent of one another. This results in the alleles of different genes being independently assorted into gametes, meaning that the inheritance of one gene's allele does not influence the inheritance of another gene's allele. This random distribution of maternal and paternal chromosomes during metaphase I contributes to genetic diversity in sexually reproducing organisms.