In a letter to Nature, Mark Ptashne, Oliver Hobert, and Eric Davidson question an editorial that appeared in the journal. The editorial, which focused on the International Human Epigenome Consortium, says that it is "clear that epigenetics … could explain much about how these similar genetic codes are expressed uniquely in different cells, in different environmental conditions and at different times."
However, Ptashne, Hobert, and Davidson say that epigenetic marks stem from the DNA sequence and its interations with RNA and proteins. "They are thus directly dependent on the genomic sequence," they write.
At Adaptive Complexity, Michael White says he agrees with Ptashne, Hobert, and Davidson. "The idea that genomes between species are too similar to account for species diversity is absolute nonsense. And so is the idea that epigenetic information is completely independent of DNA sequence," he writes.