- Mitomycin C treatment & Gamma irradiation These are mutagens that can cause DNA damage and mutations. They generally increase the likelihood of recombination or chromosome aberrations, not decrease recombination between specific genes. - Larger distance between genes Genes that are far apart on a chromosome tend to recombine more frequently, not less. - Inversion A chromosomal rearrangement that, when heterozygous, can lead to reduced recombination in the inverted region. This is because crossing over within the inverted segment and subsequent chromosome breakage can lead to unbalanced gametes that are not viable. This selective disadvantage for recombinant chromosomes effectively suppresses recombination.