Somatic loss-of-heterozygosity can result in the complete loss of function of tumor suppressor genes in human cancer. Mitotic recombination between homologous chromosomes can cause loss of heterozygosity, leading to tumorigenesis. However, the molecular mechanisms triggering and controlling mitotic recombination are largely unknown. A new study shows that genetic divergence between homologous chromosomes suppresses mitotic recombination to a varying degree in different tissues of the mouse.
