During which phase of meiosis does crossing over occur?

Crossing over occurs during Prophase I of meiosis, a critical event that enhances genetic diversity. In this phase, homologous chromosomes pair up and form structures known as tetrads. As these paired chromosomes align closely, segments of genetic material can be exchanged between them. This exchange results in new combinations of alleles on the chromosomes, contributing to genetic variation in the resulting gametes.

The process of crossing over is essential for the proper segregation of chromosomes during meiosis and helps ensure that offspring have different genetic traits than their parents. Although crossing over involves intricate processes occurring at specific points within Prophase I, the overarching concept is that it represents a crucial mechanism for increasing genetic diversity in sexually reproducing organisms.