Seggregation of Alleles
Each organism inherits two versions of every gene called alleles, one from each parent. These two alleles are found on separate chromosomes and separate from each other when gametes are formed during meiosis, with one allele ending up in each gamete.
This increases genetic variation as half the gametes get one version of the gene and half get the other version. This means the offspring produced from each type of gamete will be genetically different.