The lower incidence of homozygous mutations in genome-doubled samples may reflect the fact that more events are required to render a mutation homozygous in a genome-doubled sample (although the effect may be partially offset, however, by a possible increase in genetic instability following doubling, e.g., by centrosome duplication 42). These considerations suggest that genome-doubled samples evolve via distinct trajectories, because inactivation of tumor suppressors may occur less frequently following doubling.
