The phenomenon of human chimaeras are living proof of the complexity that results from an interplay between development and the human genome. Twin studies have shown that a majority of their epigenetic profiles are similar and the variation is related to age and other environmental and stochastic factors. Has anyone ever come across a study looking at epigenetic variation between the different cell types in a human chimaera ? Given the rarity of such an occurence, I wasnt sure if there has been such a study.