Posted for Heidi Ledford

Our DNA sequence may not be the only ‘genetic’ information that we inherit from our parents, according to a study published online this week by Nature Genetics. An analysis of identical and fraternal twins shows that epigenetic changes – in the form of a chemical modification to DNA called methylation – are also passed on to the next generation.

DNA methylation can affect gene expression, and changes in DNA methylation have been linked to everything from normal developmental changes to illnesses including cancer. Zachary Kaminsky at the University of Toronto and his colleagues analyzed DNA methylation in different cells types taken from 114 identical twins and 80 fraternal twins. The researchers found that identical twins were more likely to share DNA methylation patterns.

Now, it’s still possible that these DNA methylation patterns are more similar in identical twins simply because the underlying DNA sequence is more similar. (Methylation typically occurs where a ‘C’ lies next to a ‘G’ in the DNA sequence.) But the authors argue that their results, combined with previous data from animal models, suggest that DNA methylation is inherited.

A few of the geekier news outlets out there have done a nice job with this story (and remember, ‘geek’ is chic these days). The Scientist reminds us that the study looked only at methylation across about 1-2% of the genome, and that the next step will be to do a broader survey using more subjects. And Science News admirably ties this paper in with another, chewier epigenetics study (also published online by Nature Genetics this week. That one finds that methylation occurs near, but slightly outside of the regions in which researchers expected to find them.

Image: Anthea Sieveking , Wellcome Images