Inheritance of DNA methylation in Coprinus cinereus.

We examined the inheritance of 5-methylcytosine residues at a centromere-linked locus in the basidiomycete Coprinus cinereus. Although methylated and unmethylated tracts were inherited both mitotically and meiotically the lengths of these tracts were variable. This variation was not confined to any one phase of the life cycle of the organism, and it usually involved the simultaneous de novo methylation of at least four HpaII-MspI sites. We also found that the higher levels of methylation at this locus were transmitted through meiosis, regardless of the level of methylation of the homologous chromosome.