You can hit ‘undo’
Read the main feature story on epigenetics here.
Once a chisel hits marble, there’s no second chance for a sculptor. Many researchers thought that once a methyl group was attached to DNA, the modification was also set in stone. Carbon–to–carbon bonds between the methyl group (one carbon and three hydrogens) and the DNA base are too strong to sever, the reasoning goes. Only five years ago, Michael Meaney, a behavioral geneticist at McGillUniversity in Montreal, Canada, submitted a manuscript to a scientific journal detailing experiments showing that some genes can be demethylated — the methyl group can be plucked off the DNA base cytosine to which it is attached. The editor of the journal rejected the paper, saying that demethylation “just doesn’t happen,” Meaney says.
But recent evidence from Meaney’s lab and