Some scientists are taking issue with Pulitzer Prize-winning author and physician Siddhartha Mukherjee's piece in the New Yorker on epigenetics. In it, Mukherjee explores the relationship between nature and nurture and how that might be mediated by epigenetics. He starts his article off by sharing the story of his mother and her identical twin sister.
But as Fred Hutchinson Cancer Research Center's Steve Henikoff tells Jerry Coyne's Why Evolution Is True blog, "[t]he problems began when Mukherjee made a leap from the existence of differences between his mother and aunt to how there must be something written on the genome to remember these differences."
Mukherjee suggests in the New Yorker that environmental data becomes "etched" on the genome and that a person's experiences, such as breaking a bone, are remembered by methylation changes or histone modifications. "The genome is not a passive blueprint: the selective activation or repression of genes allows an individual cell to acquire its identity and to perform its function," he writes. "When one twin breaks an ankle and acquires a gash in the skin, wound-healing and bone-repairing genes are turned on, thereby recording a scar in one body but not the other."
Others point out that Mukherjee overlooks the role of transcription factors in gene regulation. Current Biology's Florian Maderspacher notes in a letter to the New Yorker, posted at Coyne's blog, that transcription factors, growth factors, and hormones can all alter how a cell or organism looks without changing its DNA.
Memorial Sloan Kettering Cancer Center's Mark Ptashne and John Greally from the Albert Einstein College of Medicine also go through the New Yorker article nearly point-by-point in a separate post at Coyne's blog. They also question Mukherjee's usage of Shinya Yamanaka's work on transcription factors and cellular reprogramming to bolster the idea that histone modifications regulate it all.
"Mukherjee seemed not to realize that transcription factors occupy the top of the hierarchy of epigenetic information, that this has been widely accepted in the broader chromatin field, and that histone modifications at most act as cogs in the machinery that enforces the often complex programs specified by the binding of transcription factors," Henikoff adds.
Mukherjee tells Vox that he stands by his story, as does the New Yorker. Mukherjee does, though, acknowledge that he "did not emphasize the role of transcriptional factors and regulation adequately."
"This was an error. I thought, sincerely, that I had talked about gene regulation, but an increased emphasis would have helped the piece, and not caused the polarizing response," he says.
Vox adds that the New Yorker piece is an excerpt of Mukherjee's upcoming book and that it originally was twice as long as its final 6,000 words.