Epigenetics – introductory explanations

By Grant Jacobs 06/02/2013 6

Epigenetics is a term that is increasingly being heard of outside of molecular biology or genetics.

One of my interests is how gene regulation works, how the molecules that control genes do their thing. You can think of epigenetics as gene regulation through controlling the availability of genes to be used or not.

While it’s fairly easy to offer some examples of epigenetics, it’s harder to present it a balanced way, in part because understanding it needs a little context, a little explanation of how it fits into the rest of the what‘s going on in the nucleus—the place the DNA is stored in our cells—while our bodies develop and grow.

This TED lecture by Dr. Courtney Griffin from the Cardiovascular Biology Research Program at the Oklahoma Medical Research Foundation gives some of the background.

It’s a little drier than many TED lectures*—but a lot lighter than formal lectures on the topic!—and worth viewing if you’d like to know more about epigenetics.

A lighter presentation is this from NOVA ScienceNow by Neil Tyson. Lest you think he’s not a star, Neil Tyson has over a million twitter followers.** (And counting.)

A quibble I have with this presentation is that by focusing on just one gene, some readers might come away with the idea that most of our genes will have similar trans-generational effects. In practice, there are only a few examples (from different species) known.***

As I was saying my own interests are with how the molecules that control genes do their thing. The video below has animations of molecules carrying out some of the things that take place in epigenetic regulation of genes. If you’re not familiar with molecular biology, don’t worry too much about precisely what is doing what, just the gene nature of the thing that the animation shows. It’s quite a jump from what Tyson presents to this, but this is where all the action happens.

One quibble—yes, another quibble!—about that video is that in reality the interior of cells is crowded. There‘s a wonderful illustration of how crowded the interior of cells are in a model of the cytoplasm I’ve shown readers before. If you haven’t seen it before, check it out. (Think about how things get to interact with one-another given the sheer density of stuff in a cell.) The video above has all the ‘other’ molecules stripped away. It’s understandable, it’d be impossible to see anything in the animation otherwise, but readers not knowing better might think everything takes place in empty expanses of water!

A video from an earlier post, Animating our DNA, shows an animation of chromatin and chromosomes (from about 4:45 through to about 5:30 in the video, but watch it from the start).

All these give some glimpses of what epigenetics involves, but I’m not convinced they convey the full picture well because a wider explanation of the context epigenetics works within is needed to give it perspective.**** Goodness knows if I’d find time, but it’d be good to present some sort of introduction to epigenetics that I think is more satisfying – at least more satisfying to me!


Another quibble over the third (last) video is the representation of the condensed chromatin. As you can see I could do this all night…!

* Partly because the slides are closer to student lecture material than what you’d see in, say, a popular science TV program.

** Hat tip to David Kroll (@davidkroll) for that tidbit. Via twitter, of course.

*** Thus far, anyway. I can’t help wonder if this extrapolation from a few examples partly explains many of the over-stated claimed about epigenetics in the mainstream media, or the martketing for ‘remedies’ that use the term epigenetics to create an impression of being based in science. (There are some medicines being developed that are using epigenetics for their effect – for example a number of anti-cancer treatments. More about that in a later post, perhaps.)

**** I was reminded of this by a comment following an article elsewhere which offered a brief explanation of epigenetics as part of the article.

More articles (with epigenetic themes) on Code for life:

Sea stars and mosaics

I remember because my DNA was methylated

One example of why all those genomes from different species are useful to biologists

Epigenetics, a confused muddle in the media

Epigenetics and 3-D gene structure

6 Responses to “Epigenetics – introductory explanations”

  • Funny thing, Grant, I was cruising about here looking for more science and came across your link to me. . .I guess I should blog more, eh?

    One of the problems I’ve found is trying to make science accessible and understandable to laypeople without leaving too many holes for magical thinking to creep in. I am not a professional scientist, but more of a hobbyist, teaching myself as I go along. Epigenetics and neuroscience are ripe fields for misunderstanding (and thereby for purveyors of pseudoscience) so I’m always looking for information that explains without going too far over people’s heads. So what you will find on my site is things that I think can communicate science to people who might just not get it.

    I navigated here from a newer article that was more along those lines. My experience in discussing epigenetics with regular people is that it is such a simple concept to grasp that it’s easy for them to repurpose it to mean what they want it to. The most popular one I’ve come across is that “epigenetics equals genes plus environment!” This is used to explain how we can change our genes by eating different foods and achieving spiritual enlightenment (Bruce Lipton is a favored source of this idea.)

    The other problem is a common one in science – the initial findings, once released to the public, were gobbled up and are now viewed as accepted knowledge. The fact that agouti mice changed appearance when the pups were switched to different mothers is the sine qua non for speculators, and they often point to that research as proof that stress causes heritable changes. Don’t try to point out that further research showed that some changes were reversible in other experiments, or that the epigenetic changes in those agouti mice didn’t last past the second generation – it goes counter to the goals of people who want to scare parents into thinking they need to subscribe to some sort of behavioral regimen or risk polluting their descendants’ DNA forever.

    I guess that what I’m trying to say is that scientists might want to be aware that there’s a large gap between what is introductory for them and what is introductory for the general public. You can’t dumb it down without making it wrong, but you sometimes need people who aren’t experts to tell you where the line between too hard to understand and too easy to misinterpret lies. It’s kind of wiggly, too.

    I have to say, though, that scientists who blog are doing wonderful things. It’s sometimes difficult to learn all the individual pieces of concepts so you can understand the concepts, absorb the vocabulary, and go back and start over when you find out you were wrong about something. Eventually, though, you learn not only from the bloggers, but from their commenters, and things start to make sense. So. . .thanks for explaining things!

  • Alison,

    Thanks for the kind words. I should be writing more on epigenetics soon. In fact, I meant to have a post up this week, following on from a comment on the Tuatara genome project blog. (Speaking of which, I probably should get onto that…)

    In case you’re interested – I’ve written on reporting ‘initial findings’ and later developments, too. That’ll be preaching to the choir here, though!

    You wrote, “I guess that what I’m trying to say is that scientists might want to be aware that there’s a large gap between what is introductory for them and what is introductory for the general public.”

    On that note, I try remind myself that sometimes articles about things that might be basic background knowledge to a scientist can be interesting—and hopefully fun—to others if presented in the right way. (I’ve got one in draft form that’s a bit like that. Another thing to get around to doing…)

  • Yes, preaching to the choir, and when I first realized that John Ioannidis had a good point, it made me kind of sad. Then what made me sad was that I didn’t have professional journal access, so when I went to PubMed all I saw was abstracts, so I couldn’t see for myself what was potentially hyperbole!

    I have your other links opened in tabs. Last night I decided that I was going to blog about randomness – a concept that makes perfect sense to scientists and mathematicians, but means something completely different to the average joe. Sort of like “theory,” you know?

    The reporting of findings adds another dimension of misunderstanding. Too many Science Journalists know nothing about either, and they’re getting all their information from abstracts and press releases. Something I do for fun every once in a while is google an author’s name or a paper’s name just after a finding has been released, collect the titles of the articles that show up in the first pages of the search, then compare and contrast them with what the paper actually said. It’s almost as much fun as using Babelfish to translate something from English to Korean and then back to English!

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