Nessa Carey wrote a horribe book about junk DNA where she completely misunderstood the science. It's one of many examples of bad science journalism [Nessa Carey doesn't understand junk DNA].
I recently became aware of a talk given in 2015 by Nessa Carey on epigenetics so I'm posting it here. (She also wrote a book about epigenetics.) She is an entertaining speaker and gives a very good presentation but that's a problem if the science is misleading. Judge for yourselves.
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I'm just at 54 seconds into the video, and the 1st slide has the wrong left-handed DNA helix!
Wow! This talk is riddled with so many misconceptions, it deserves a blog article all by itself. Crocodile temperature-dependent sex determination, metamorphosis of a fly larva into an adult fly - these are examples of epigenetic phenomena?? *Facepalm*
Under the historical definition of "epigenetic", they are. Under the hip modern definition, they aren't. So maybe she's being historical?
I see. If that’s the case, then she’s absolutely right, and I stand corrected. I’ll look into the historical definitions of Epigenetics, John; thanks for the pointer.
John, I can think of three definitions: (1) Waddington's original definition which more or less equates it with interactions among genes and cells and environments in the process of development. Irrelevant here? (2) Non-sequence-altering DNA modifications or histone modifications that happen in normal development and are not passed on to offspring, and (3) Modifications of those type that are passed to offspring, at least for a while. Which of these is Carey discussing? Number (3) is the one involved in the current wave of science confusion and commercial hype. Or do I misunderstand all this?
This is an old debate. The only useful definition in modern terms is the Robin Holliday definition because all the others fall under regulation of gene expression and nobody since Monod & Jacob thinks that's going to bust any paradigms.
https://sandwalk.blogspot.com/2017/01/what-heck-is-epigenetics.html
Larry, thanks for the reference. I would suggest that in multicellular organisms there should be a distinction made between epigenetics (sensu moderno) which involves inheritance through cell divisions, but does not get passed on to the next generation. Versus epigenetic changes which can get passed on to the next generation. The former seem much less controversial than the latter.
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