Mutational risks in females: genomic imprinting and maternal molecules

Genetic mechanisms for selective mutagenesis in female mammals might include alterations of genomic imprinting, maternally derived molecules, mitochondrial DNA or sex chromosome loci. None of these mechanisms provides an obvious explanation for the higher mutational rates observed for certain mutagens in mouse female pronuclei, but the association of DNA methylation with maternal genomic imprinting is an enticing avenue for research. Further characterization of the extent and homology of genomic imprinting among mammals is required before its relevance to mutagenesis can be determined. The existence of maternal effect mutations in mammals merits evaluation but is not yet proven. The relevance of mitochondrial DNA to female-specific mutagenesis will be greatest in multi-generational studies.