What process can result in increased genetic variation during reproduction?

Crossing over is a process that occurs during meiosis, specifically during prophase I, where homologous chromosomes exchange segments of genetic material. This genetic recombination results in new combinations of alleles, which increases genetic variation among the gametes produced. As a result, when these gametes combine during fertilization, the offspring have a unique set of genes contributed by both parents. This increased genetic variation is crucial for evolution and adaptation in changing environments, as it provides a diverse gene pool for natural selection to act upon. In contrast, DNA replication and gene regulation do not create new genetic combinations, and while mutations can introduce new genetic material, they occur randomly and are less predictable in terms of contributing to variation compared to the systematic process of crossing over.