Abstract.
The function of DNA methylation has been investigated in depth in vertebrate and plant genomes, establishing that it is involved in gene silencing and transposon control. Data regarding insect methylation, even if still scanty, apparently argue against evolutionary conservation of DNA methylation functions. Cytosine methylation, therefore, proves to be an epigenetic tool repeatedly used to accomplish different functions in different taxa according to a sort of epigenetic tinkering occurring during evolution.
Key words. Epigenetics, DNA methylation, DNA methyltransferase, gene expression, cytosine methylation functions, invertebrate-vertebrate transition
Footnotes
Received 27 April 2004; received after revision 18 June 2004; accepted 7 July 2004