New Study of Epigenetic Changes

The NYT is reporting on a new study in the Proceedings of the National Academy of Sciences on the differences in the epigenome of twins as they age. For some reason I can't find the original study on the PNAS site. Either it's not up yet, or I am simply retarded.

In any case, the researchers document that as twins age, their epigenomes diverge. Further, the divergence is not random, but driven by environmental factors: twins who have lived apart longer show greater epigenetic divergence. The study looked at methylation patterns and the acetyl groups that attach to histone proteins.

I'd like to teach philosophy of biology next spring: I promised Lisa Lloyd I'd assign her book to students who would actually pay for it, rather than just receive a spiral bound xerox. One of the things I'd like to look at is the way epigenetic inheritance changes our understanding of the role of the genome in evolution. I'd really like to read Oyama *The Ontogeny of Information* and Keller *The Century of the Gene.*

Update: John Hawks has also posted on this, and links to the WaPo article on it. Rick Weiss at WaPo says in passing that epigenetic information is not inhereted, and Hawks does not contradict him. I understood that methylation patterns could be inhereted--they are passed down matrilinarly with the cytoplasm. I should read more on this.