Chris Kresser recently released a podcast explaining the basics of methylation: explaining heterozygous vs homozygous, genetics vs environment, impacts on the body, etc.. I found it really helpful as I have never wanted to dive into methylation stuff as my mind is already boggled enough. He broke it down really simply. Rick Van K also got a mention. It is well worth a listen: https://itunes.apple.com/us/podcast/revolution-health-radio/id372257397 I couldn't figure out how to link directly to that specific podcast but it is currently the second one down on the list and is clearly titled 'Methylation'.