Frequent paramutation-like features of natural epialleles in tomato

Paramutation is a natural epigenetic process that occurs in plants and animals that is associated with methylation-mediated gene silencing. The curious thing about a paramutated allele is than it can transfer its silenced state to its homologous and active allele. This freshly paramutated allele then becomes silenced and acquires the ability to silence other active alleles in subsequent generations, so that inheritance patterns are non-Mendelian. Gouil and Baulcombe worked with hybrid lines between Solanum pennellii (the wild relative of tomato) and Solanum lycopersicum cv. M82 (a domesticated cultivar of tomato). They studied a particular locus that they characterized as paramutated. The authors propose a correlation between high levels of production of small RNAs and a rapid transfer of the epigenetic marks. The authors conclude that, “paramutation-like epigenetic interactions are common for natural epialleles in tomato, but vary in timing and penetrance.” This finding is particularly interesting due to the wide-scale practice of making hybrids to enhance agronomic characteristics. (Summary by Aime Jaskolowski) bioRxiv 10.1101/177972