Full circle

The final aim of the twins study is to relate differences in epigenetics between all twin pairs to pair-specific differences in maternal nutrition. For instance, the team will examine the general relationships between global levels of DNA methylation and levels of metabolites such as folate.

"Analysing genetics entails a lot of 'noise' that can mask epigenetic changes," Craig says. "Studying monozygotic twins avoids this by controlling for genotype and therefore any differences detected are either random or due to small changes in environment such as share of the placenta. On the other hand, the dizygotic or fraternal twins are interesting because they are essentially controlled for environment but have different genetics."

Craig is coming full circle at this year's Lorne conference after being 'converted' to microarray-based approaches to epigenetics at Lorne about four years ago. "It blew me away when I saw a talk on epigenetics by someone who had put the whole yeast genome on a microarray and hybridised their particular fractions of chromatin," he says. "They could then make conclusions about the kind of epigenetic modifications that were going on in the yeast genome.

"I thought there and then that is the field for me, and I saw the future - a diagnostic test. Any test that can help predict the onset or severity of disease, even in combination with genetic tests, will be useful, especially for those complex conditions such as psychiatric, metabolic and cardiovascular diseases for which few tests are currently available.

"The most exciting area of epigenetics will be finding associations between disease, looking at epigenetic changes when someone has a disease, but also analysing the changes over time, and more importantly the health predisposition of an individual. Can we look at people at birth and predict the kinds of diseases they might get? And because epigenetic marks are potentially reversible, can we then treat with specific drugs and prevent or even reverse the process?"