How does meiosis contribute to genetic variation

Genetic variation is increased by meiosis

During fertilisation, 1 gamete from each parent combines to form a zygote. Because of recombination and independent assortment in meiosis, each gamete contains a different set of DNA. This produces a unique combination of genes in the resulting zygote.

Recombination or crossing over occurs during prophase I. Homologous chromosomes - 1 inherited from each parent - pair along their lengths, gene by gene. Breaks occur along the chromosomes, and they rejoin, trading some of their genes. The chromosomes now have genes in a unique combination.