Dissection of the Signal for DNA Methylation in the - Region of Neurospora

Some of geneticists' favorite eukaryotic organisms, such as Drosophila and yeasts, have no detectable DNA methylation. This tempts one to consider methylation an unimportant frill on eukaryotic DNA. It is now known, however, that DNA methylation is essential in mice (Li et al. 1992 and this volume). Mutations in the DNA methyltransferase gene block embryonic development. The reason that methylation is essential for development is unknown. Thus, although it is clear that DNA methylation is important, at least in some organisms, we remain largely in the dark both about its function and about its control in eukaryotes.