November 29, 2019, by Brigitte Nerlich

“It’s just like epigenetics” – scientific metaphors for non-scientific concepts

This is a guest post by Cath Ennis. Cath is a Knowledge Translation Specialist with the University of British Columbia’s Human Early Learning Partnership and the Kobor Lab at BC Children’s Hospital Research Institute.


In our new paper, Brigitte Nerlich, Aleksandra Stelmach and I examined the metaphors used by academic social scientists and alternative health marketers to describe and discuss epigenetics. We found some overlap between the metaphors used by these two very different publics, as well as some shared misunderstandings and over-interpretations of the science of epigenetics.

I’ve been intrigued for years by the diversity of the metaphors that people use to explain epigenetics, and by how such metaphors can highlight some of the common misperceptions of the field. In my 2017 book “Introducing Epigenetics: A Graphic Guide” I referred to the DNA sequence as the text of an instruction manual, and epigenetic marks as highlighting and crossing-out that helps each type of cell to identify which parts to use and which to ignore. My colleague Dr. Michael Kobor refers to genes as lightbulbs and epigenetic marks as dimmer switches, and I’ve seen others use everything from hardware/software to musical scores/artistic interpretation to describe the same phenomena. (Aviad Raz, Gaëlle Pontarotti, and Jonathan Weitzman published a fantastic paper earlier this year about how different epigenetic metaphors are perceived by technical and non-technical audiences, which I highly recommend reading if you’re interested in this topic).

While working with Brigitte and Aleksandra on our paper, I also stumbled across various examples of the opposite case: of people using epigenetics as a metaphor or analogy to explain non-biological concepts. This seems to be a recent trend (quite possibly a premature one, given that even biologists can’t agree on the precise definition of epigenetics), and one deserving of a more systematic analysis than is possible in a short blog post. Hopefully, though, the four diverse examples presented here can provide a good starting point for whoever wishes to pick up this baton!

Mapping aspects of molecular epigenetics onto sacred texts

The first example is a comparison between different cells using different parts of the genome, and different Christian denominations using different parts of the bible in their sermons. I encourage you to read the entire article by David Sloan Wilson, SUNY Distinguished Professor of Biology and Anthropology at Binghamton University, but here are the most relevant parts:

“sacred texts bear an intriguing resemblance [to] genomes. Both are replicated with a high fidelity and even have a hierarchical and segmented structure. The Protestant Christian Bible, for example, is segmented into 66 books, which in turn are divided into chapters and verses. […] 

Just as differences in gene expression are often visualized in the form of “heat maps” (the brighter the color, the more the gene is being expressed), we can create a heat map for the expression of books in the bible [this refers to the use of different parts of the bible in sermons] by the six churches. […]

Thus, when differences in Biblical citations are combined with differences in interpretation, the concept of a sacred text as a cultural epigenetic inheritance system, capable of adapting a religious community to a wide range of environmental circumstances, has much to recommend it. […]

Formalized sacred texts such as the Bible or Quran are the cultural equivalent of an epigenetic system because only the expression of the passages, and not the passages themselves, are allowed to change. However, the cultural equivalent of genetic evolution (the addition and subtraction of the passages) took place at an earlier stage of their history and to some extent still, to the extent that religions accumulate supplemental texts in addition to their core text. During the Protestant Reformation, even the core text of the Catholic and Orthodox Christian Bibles was reduced”

Here we have a metaphor that I think would work well in either direction, and that’s pretty similar to my own preferred epigenetic metaphor of text and highlighting. The author seems to have a solid grasp of the science of epigenetics, and applies it to a concept that does indeed have a number of parallels to genetic regulation.

Mapping aspects of epigenesis onto understanding how robots learn

Our next example is drawn from the world of epigenetic robotics. I’ll freely admit that I don’t have anywhere near enough knowledge of robotics to truly understand the nuanced distinction between epigenetic and other forms of the discipline, but the primary allusions here seem to be to the role of epigenetics in human development, and the concept of epigenetic plasticity in response to changing environments.

Epigenetic robotics is concerned with the study of cognitive development in natural and robotics systems”, and what it can tell us about “the typical and atypical development of children, and creating better robots as well as the appearance and modification of cognitive structures in a progression from the embryo to the adult form”. According to Jordan Zlatev and Christian Balkenius, “The term was used to refer to such development, determined primarily by the interaction between the organism and the environment, rather than by genes”.

The focus of this metaphor is on the plasticity afforded to organisms by epigenetic marks that change during development and in response to certain environmental exposures. If I’m understanding these texts correctly, what this means to a robot relates to how it learns from experience rather than from pre-programmed routines.

My perception of the robotics metaphor is that it’s built on a solid foundation, but might overstate the science to some extent. Epigenetic marks do change during human development (some of them so predictably that our group at BC Children’s Hospital in Vancouver has used them to develop an “epigenetic clock” to assess childhood development), but to what extent these epigenetic changes actually drive rather than merely reflect pre-programmed (genetic) and responsive biological changes is still a matter of active scientific debate. Perhaps this distinction isn’t critical to the use of the word epigenetics in the field of robotics, though – I’m hoping that a reader who knows more about robotics than I do can help to enlighten me on this point!

Using epigenetics as a free-floating signifier attached to ‘cultural DNA’

I also spotted a reference to epigenetics in an article written by anti-bullying activist Monica Lewinsky for Vanity Fair in 2018:

“something fundamental changed in our society in 1998 […] And ever since, the scandal has had an epigenetic quality, as if our cultural DNA has slowly been altered to ensure its longevity. If you can believe it, there has been at least one significant reference in the press to that unfortunate spell in our history every day for the past 20 years. Every. Single. Day.”

This is a bit of a puzzling one. At first glance, Lewinsky’s metaphor seems similar to the use of epigenetic concepts to describe how sacred texts and their interpretations change over time. However, the references to cultural “DNA” being altered slowly, and with long-term effects, seem to contradict the common perception of epigenetic changes as a faster and more transient alternative to the slower and more permanent evolution of the genetic sequence. My best guess here is that the author has heard of epigenetics as a new concept in evolution and/or phenotypic plasticity in response to environmental changes, and used the term in her article to draw attention to her theme of the lasting cultural impact of her unique experiences in 1998, despite these contradictions. As such, I would say that this comparison is based on an incomplete understanding of the science of epigenetics. (my apologies to Ms. Lewinsky if my assumption is incorrect!).

And finally: the metaphor of epigenetics detaches itself from all meaning

In his recent novel “Bob Honey Who Just Do Stuff”, the actor Sean Penn writes:

“While the privileged patronize this pickle as epithet to the epigenetic inequality of equals, Bob smells a cyber-assisted assault emboldened by right-brain Hollywood narcissists”

What does ‘epigenetic’ mean here, other than a technobabble word that’s fashionable and sounds sciencey? Something to do with subtle differences between superficially equal entities, such as the common trope in the public discussion of epigenetics of DNA methylation differences between genetically identical twins? Something else? All answers welcome!

Epigenetics as a (flawed) tool to think with

So there we have it: four examples of people using epigenetics as a metaphor to explain three very different concepts, plus one rather nihilist use of the word. As we also saw in our published analysis, these examples use different aspects of the popular understanding of epigenetics to drive their comparisons, with varying success in terms of scientific accuracy.

I think we’re going to see more examples of this phenomenon arise as discussions of epigenetics continue to migrate out of academic science and into more common usage. I also think that epigenetic metaphors are likely to add to the rather muddled nature of the public epigenetics discourse; some of the same misunderstandings that we highlighted in our paper are already apparent in these first few reversed comparisons that I stumbled across (and also in some of the uses of epigenetics that I’ve seen crop up in science fiction, which is a topic for another day). I believe that all scientists working in this field should be aware of common public perceptions and misperceptions of epigenetics as we endeavour to communicate our work to non-expert audiences; paying attention to the epigenetic metaphors people use – in either direction – is part of this awareness.

Image: Writing Robot (writing a biblical text), Wikimedia Commons

Posted in epigeneticsMetaphors