Paramutation

Paramutation, in epigenetics, is an interaction between two alleles of a single locus, resulting in a heritable change of one allele that is induced by the other allele. Paramutation violates Mendel’s first law, which states that in the process of the formation of the gametes (egg or sperm) the allelic pairs separate, one going to each gamete, and that each gene remains completely uninfluenced by the other. In paramutation an allele in one generation heritably affects the other allele in future generations, even if the allele causing the change is itself not transmitted. What may be transmitted in such a case are RNAs such as piRNAs, siRNAs, RNAs. These are packaged in egg or sperm and cause paramutation upon transmission to the next generation. This means that RNA is a molecule of inheritance, just like DNA.