Inheritance of acquired traits in plants: Reinstatement of Lamarck

Since Lamarck proposed the idea of inheritance of acquired traits 200 years ago, much has been said for and against it, but the theory was finally declined after the 1930s. Despite of the negative opinions of the majority of geneticists, botanists and plant breeders have long recognized that altered properties during the growth were occasionally transmitted to the offspring. This was also the case with artificially altered properties such as dwarfism, flowering timing and plant stature, which were induced by a non-mutagenic chemical, 5-azacytidine and its derivatives. As these drugs are powerful inhibitors of DNA methylation in vivo, a close correlation between methylation and phenotypic expression was suggested. Subsequent studies showed that rice plants acquired disease resistance upon demethylation of the corresponding resistant gene, and that both resistant trait and hypomethylated status were inherited by the progeny up to nine generations. Whether or not the methylation pattern changes under natural...