Whether cytosine methylation is the explanation for this difference has yet to be tested, but something is clearly happening.

The extent and pattern of cytosine methylation in 24 navel orange cultivars, genomes were assessed by using the technique of methylation-sensitive amplified polymorphism (MSAP).

Mammals appear to have taken advantage of the possibilities afforded by cytosine methylation to provide a heritable mechanism for altering DNA-protein interactions to assist in such silencing.