Recent studies have even reported initial findings suggesting that an additional mode of epigenetic regulation, namely conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), may play a role in the reprogramming of the zygote (Wossidlo et al., 2011). Further studies will be necessary to further understand the implications of these findings on the patterning of methylation marks during development, as well as the effect of exposures on the underlying mechanisms.
