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Epigenetics: How Environment Shapes Our Genes

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The burgeoning new science of epigenetics offers a cornucopia of insights some comforting, some frightening. For example, the male fetus may be especially vulnerable to certain common chemicals in our environment, in ways that damage not only his own sperm but also the sperm of his sons. And it 's epigenetics that causes identical twins to vary widely in their susceptibility to dementia and cancer. But here 's the good news: unlike mutations, epigenetic effects are reversible. Indeed, epigenetic engineering is the future of medicine.

256 pages, Paperback

First published January 1, 2011

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About the author

Richard C. Francis

7 books26 followers
Richard C. Francis is a writer who has a PhD in biology from Stanford University. He is the author of Why Men Won't Ask for Directions. He lives in New York City.

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Displaying 1 - 30 of 100 reviews
383 reviews2 followers
July 22, 2011
Why aren't identical twins actually identical? Why are genetic clones not identical? Do stressed moms bear stressed children? Why is the product of a cross between a male donkey and a female horse different from a cross between a female donkey and a male horse? Why do some cancers appear to regress without any obvious reason? Questions like these are addressed in this book as it attempts to introduce a curious but uninformed audience to some fascinating discoveries in genetics. Epigenetics is a field that investigates how the same genes in two different people can be expressed differently with a special emphasis on the role of the environment. The most famous examples are addressed in this book but unfortunately for those who follow science news, very little new information is presented that has not already been available as news reports. The chapter titles are full of promise but at the conclusion of each chapter, one is left feeling that just when the topic is becoming interesting it abruptly ends and a new chapter begins. The most interesting chapter dealt with the role of epigenetics in fetal development. Interesting ideas were presented throughout the chapter. If the entire book were written in this manner, it would have satisfied both the casual reader curious about genetics as well as the science reader eager to learn and think about the subject.
Profile Image for Elena.
143 reviews34 followers
February 10, 2019
I read this book to brush up on my favorite science biology topic, Epigenetics. It's by far the most spectacular field of science, probably after Immunology, in my opinion anyway. It's meant to be for the layman person, but there are definitely some parts of the book that might fly past you if you are not of a science or biology background. Nevertheless, if you want to know what Epigenetics is all about this is the book you can to start with.

This book actually starts off a little dry for someone with a biology background. A lot of definitions; epigenetics, DNA, RNA, proteins, histones, transcription, translation. It wasn't actually until later in the book, past the half-way point that I actually got more intrigued. I debated several times putting it down because it was so redundantly basic. On the other hand, if you do not have a biology background, and you're interested in knowing these things, this book will be perfect in the first half or so.

As the book unfolds into the later chapters, the subject of epigenetic gene regulation of cancer cells is by far the most fascinating subject of this book. Everything in the first part of the book will lead you to the understanding of this topic. For a long time now, the study of cancer has solely focused on mutations of specific genes that appear to be located in cancer tumors. Later, in more recent years, cancer research has been aimed at epigenetic therapy, and as a result research on epigenetic gene regulation of cancer tumor cells.

So if you aren't familiar with the subject, this is a great book to introduce you to the following ways cancer tumor cells are epigenetically regulated: DNA methylation of certain oncogenes (aka cancer genes), Histone modifications, and microRNA epigenetic regulation-also known as RNA interferences. If you have no idea what these mean, this book is a great introduction to these pathways of epigenetic regulation and how they are being studied to understand epigenetic therapies for cancer patients. In many cases, the causal effects of cancer can be reveresed because epigenetic regulation is also a reversal process. So in the cases where the genes themselves aren't mutated, but it is the epigenetic regulation leading to the tumor, then epigenetic therapy can be of great influence and treatment.

This is a great introductory book to epigenetics for those of you who want to know more about the subject. It is also a great book to also those of you who have a background in biology because it does follow up with some really good research and it does give an overview of some biological concepts such as X-Chromosome silencing, Developmental biology, and also animal studies used for epigenetic research - like the ones done on sea urchins.
Profile Image for Charlene.
875 reviews700 followers
December 25, 2016
Absolutely fantastic introduction to epigenetics, albeit much shorter than most books. He introduces all the usual studies but I didn't feel bored at having heard all of it before. Francis did a really nice job of explaining various techniques for the epigenetic modification of genes-- those during transcription (e.g. methyl and acetyl groups) as well as translation (e.g. awesome microRNAs, which I love like crazy).

Francis also killed it when explaining imprinting. There exist differences between maternal and paternal stamps on the same region of a gene, which bring about 2 completely different outcomes. For example, depending on whether the male or female stamps the gene on chromosome 15, the offspring will have either Turner's syndrome or Prader-Will syndrome. But the best part about imprinting was that it was found that neither the male or female stamp the actual gene. The methylation imprinting site is not on the gene or even the control panel. It's on a region far away, called the imprint control region (ICR). These modifications are passed down transgenerationally. Some researchers argue that imprinting cannot be considered epigenetic modification. Francis' response to that is basically, "Fine, call it what you like. It is still a case of transgenerational inheritance not passed down purely by genes. Thus, we must update our understanding of how genes work and their place in evolution.

Also enjoyable was the way Francis ended the book. He stayed away from religion until the end. However, he seemed to need to say one thing before ending his book. The argument went sort of like this:

If you want to suggest God cured cancer, because it went into spontaneous remission, that if fine, but you will need a much better argument than, 'Doctors cannot explain it; so therefore God did it." There are many things we have not understood throughout history that we initially attributed to God and later came to understand when more information was available. Once understood, there was no longer a need for supernatural explanations to describe what seemed mysterious.

Currently, as we understand more about epigenetics, we understand more about how oncogenes, cancer genes, can turn back into normal genes, even in later cancers. It doesn't happen often, but if the conditions are right, it can and does happen. The process by which this occurs is being mapped. Once we understand this, what will do to the argument, "Doctors cannot explain it; so God must have done it"?

Great book!
Profile Image for Kerry Cunningham.
17 reviews6 followers
September 21, 2012
Once upon a short while back in history (mid-19th Century), it was not uncommon for people to believe in stories such as this one about the giraffe's neck:

Because for the longest time giraffes made their living reaching up into trees, stretching for all they were worth to get those last sumptuous leaves, during the lifetime of each giraffe its neck would gradually be stretched and (here's the important part) they would pass on these gradual improvements in neck length to their off-spring. Eventually, you get a species of long-necked creatures called giraffe's. In technical parlance, it was called the inheritance of acquired characteristics. 

This notion that characteristics acquired during a lifetime could be passed along to the next generation fit nicely with the zeitgeist of the time, which envisioned history as the story of the gradual progression of life toward some sort of eventual perfection. This conception of evolution was named Lamarckian evolution after its principal 19th century proponent, Jean-Baptiste Lamarck.

Today, this hopeful version of evolution sounds harmless, if impossibly naive, but in the Stalin-era  Soviet Union, it (like much else) turned deadly. Stalin loved the idea that the fruits of hard work today (bigger muscles, fuller brains, workier workers) would be passed along intact to the next generation, and Trofim Lysenko took full advantage. You might work this generation of comrade's to death, but their children would last a bit longer and work a bit more. And their children the same, ad paradisium. With Stalin's blessing, Lysenko transformed the Soviet Union's agriculture through a series of "reforms" that were based on the wildly wrong idea that wheat (or anything else) would 'learn' how to thrive in hostile environments, pass along that learning to a next generation, and eventually feed the Soviet Union's millions. It didn't. As a result of Stalin's all-in investment in Lysenkoism, millions died of starvation (not to mention the hundreds of scientists who spoke out against Lysenko and were shot or sent to Siberia). The damage was not limited to the Soviet Union. Lysenko's politically motivated pseudoscience was also widely adopted in China, contributing to the great famine of the late 1950s and early 1960s, which took as many as 15 million lives and probably many more.

So, by now we are well past sucky Lamarckian, Lysenko-eque notions of evolution.

Or were. Because now the idea that we can acquire characteristics as a response to our environment, which we then pass along to our descendants, is making a come-back.

This time, the science makes sense. It's the science of epigenetics, and the latest book by geneticist Richard Francis does an excellent job of recapping and explaining the science. Here's the deal in a nutshell:
For deeply historical reasons, our genes are first transcribed into a chemical, RNA, which is eventually translated into proteins, which then do pretty much all the work of making and caring for our bodies. Mutations in genes over time produce changes in the proteome (the set of proteins that make up a body), which results in different creatures. But now we know that there's more to the story. Chemical markers that are attached to genes, and which often end up there as a result of things experienced during a lifetime, can dramatically alter how genes are expressed. As an example, when a child is raised in a stressful environment, epigenetic changes may cause the child to more readily produce stress-related hormones, and those epigenetic changes may last throughout the person's lifetime. Even under low stress situations, that same child may produce more of the harmful stress hormones as an adult.

In rare (but frequent enough) cases, these epigenetic changes may be passed on to the unfortunate person's children, who may be born with the chemical markers that cause excess production of stress hormones. Because the parent was stressed out as a child, the next generation is born a stressed out child and may very well pass along that inherited characteristic. And so on down the generations.

It is Lamarckian evolution in action, and Francis does an excellent job laying out the story of how it works, how big a deal it is, and what kinds of problems are caused epigenetically, including (for some) a tendency to get fat.

Fascinating stuff, this.

A note on the read: There's almost as much book in the footnotes as in the main text. I covered it after the main text. I'd recommend not skipping the notes.Epigenetics: How Environment Shapes Our Genes
Profile Image for Nicky.
4,138 reviews1,113 followers
November 11, 2016
Epigenetics is one area of science that just delights me — even the fact that it really irritates people because of potentially Lamarckian interpretations kind of amuses me. It’s based on solid research about the large scale effect observed from the ‘Dutch Hunger Winter’, and the impact it had on the gene expression of not only children of those who went through it, but grandchildren as well. Given the solidity of that research, it always weirds me out when people want to claim epigenetics is just the latest fad, like it’s not valid. It explains a lot, and we know its mechanisms and can predict its effects: isn’t that enough?

This book is a reasonable introduction to the subject, simple enough for a complete layman to understand. In fact, at times it almost detours away from science into literary criticism, discussing the portrayal of PTSD in different characters in a particular movie. It’s relevant as an example, but there’s so much space spent on it, it was a bit irritating — especially if you know nothing of the movie. It also covers pretty basic science, explaining not only how epigenetics works (in a very basic sense), but also how genetics works.

I actually listened to this as an audiobook, while crocheting, and though I have no specific complaints to make of the narrator, neither did he fill me with any kind of enthusiasm. I’m not sure if that’s how I’ll universally feel about non-fiction audiobooks, since of course, the reader doesn’t need to act. Still, he’s saying these awesome things about how our bodies work, and he sounds like he’s reading out a recipe for bread. It feels weird!

Originally posted here.
Profile Image for Elizabeth Robinson.
Author 3 books23 followers
January 3, 2016
A quick note on the subject of this books:
-Epigenetics is, as the title claims, the study of how our genes interact with the environment around us. This new subfield of Genetics has been developing ever since we realized that our genetics expression can change without mutations. In my own words, an individual (such as you) can evolve based on the environment that you're put in. Not just on a psychological level, but your environment actually changes your genetics. My personal favorite experiment, not mentioned in the book, is on the inheritance of fear. Yes, if not all of the epigenetic markers are removed before fertilization, fear can be inherited. The book focuses more on epigenetic's "intended" natural function: gene regulation (ex. turning on certain hormones when you're exposed to long periods of stress, etc.). The mouse fear study I'm referring to can be found here


Now, at first I was angry with this book. I've been a huge fan of Epigenetics for a while, and I was really hoping for some juicy details on things like inheriting fear or changing eye-color. It did touch on the subject of epigenetic differences in identical twins, and it did touch on inherited stress/famine responses, but mostly the book talked about gene regulation and effects on early childhood. But once I accepted that this was vital information, I got more invested in the book.


And THEN I got to the chapters about color blindness and Mules/hinnes. WOW that stuff is fascinating! And, of course, the book does a wonderful job of explaining things. Some things seemed oversimplified to me (but that might be because I'm planning on majoring in biology), but oversimplified is better than under-simplified when it comes to non-fiction.


You want to know whether or not I recommend this book?

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Read it.


It's not witty or anecdotal, but the subject is so exciting! And I never once got angry at the book for a lack of explanation.

3 reviews
January 6, 2015
I was at the public library in the biology section looking for another book to keep my mind busy during slow bouts at work and came across this book by Richard Francis. Although the cover of the book looked familiar, likely from previous searching on Goodreads and Amazon, I couldn't remember how other people rated and reviewed it, but I picked it up anyway because it looked like a quick read, and it was.

After reading the book, I felt kind of deflated as it didn't satisfy my curiosity about epigenetics. The book was touted on the back cover and elsewhere as highlighting the exciting new science of epigenetics. . 'non of which is discussed in this book' I thought. For example, during the chapter outlining post-traumatic stress disorder, the author spent 5 pages describing the plot to "Deer Hunter" versus one sentence describing the biochemistry underling certain stress-related phenotypes (DNA methylation). After about page three of describing the movie, I kind of chuckled and flipped through to see exactly how long he would continue to write about it, and it turned out to be five pages.

Additionally, in an attempt to avoid jargon I think, some things were over-simplified to the point that they are incorrect and somewhat misleading. For example, on page 26 he mentions that sex steroids are transcription factors. Actually, sex steroids act on transcription factors and promote gene regulation. I found that a little distracting but that is likely just due to my background in biochemistry.

One thing I did enjoy his highlighting of the fungicide and rat sperm production experiments, and how it affects multiple generations.

Overall, this book had little explanation of epigenetics and focused more on the effects of epigenetics. The author did avoid using jargon, which was one of the goals outlined in his introduction, but I think his overdid it to the point that a lot of interesting science was overlooked.
Profile Image for Kat V.
1,098 reviews6 followers
April 14, 2024
Quite honestly this just isn’t that interesting. It’s not awful but it just didn’t have as much information as I was hoping and it was a bit elementary. 3 stars even
Profile Image for Sally.
1,477 reviews54 followers
September 25, 2012
Intriguing findings, just giving readers a taste of several discoveries and applications in this new field, whetting their appetite to go find out more. I found particularly interesting his discussion of preformationism (that the entity exists in its entirety at the start of conception and grows) vs. epigenesis (that an embryo evolves through the process of cellular division and specialization into a type of entity that wasn't pre-existently there at the beginning of the process). The popular idea of DNA as the software or container of an entity's being is a kind of preformationism, and this book disputes that interpretation of the nature and function of DNA, holding that DNA is simply another portion of the reproductive hardware, not the controlling software.
Profile Image for Michael Vagnetti.
202 reviews30 followers
August 9, 2013
An extended essay on the fascinating subject of how the environment affects genes without changing the DNA sequence. The argument is that genes are not always in executive control, but work, "improvisationally" within the biochemical environment of the cell. Social inheritance, for example, is discussed: how our cultural decisions end up making an imprint on who we are as biological humans.
Profile Image for Yaravid Johnson.
11 reviews
January 19, 2021
There’s a reason I don’t read non-conical, dated science books.... while the genetics refresher was NiCe, there’s nothing in here that isn’t mentioned in an undergrad genetics class. This would be a good read for someone who has absolutely no concept of genetics and wants to learn something ‘new’, and has no issue with religious bias.
Profile Image for Tad.
11 reviews
April 29, 2019
Very informative and entertaining update on the various epigenetic mechanisms that moderate inheritance. New to me were the fact that the second X chromosomes are not fully inactivated in women; microRNA; and some of the information about stem cells, methylation and protein interactions. There is such rapid progress in the genomics, proteomics and stem cell research areas that I expect a revised and ten-year-updated 2nd edition would be useful in 2021.
Profile Image for Nikki.
423 reviews
June 17, 2018
Interesting information, but very high level. I was wanting a little more depth.
Profile Image for sabisteb aka callisto.
2,342 reviews1 follower
August 16, 2016
Epigenetik, als Student habe ich sie gehasst, denn sie ist ein Teil der Biologie, den ich als deskriptive Grabsteinbiologie beschreiben würde. Damit ist gemeint, die Epigenetik beschreibt diverse Phänomene, bei denen sie im besten Fall noch grob beschreiben kann was Ursache des beobachteten Phänotyps ist, sie ist aber weit davon entfernt, erklären zu können, warum und was passiert. Die Namengebung der beobachteten Effekte werden für gewöhnlich nach dem Wissenschaftler, dem Patienten an dem man es beobachtete oder so benannt, dass Kollegen aus anderen Ländern, die man nicht leiden kann, die aber auf dem Thema arbeiten, diese weder aussprechen, noch ohne Probleme schreiben können (Ich sag nur, das Gen namens Krüppel, die Amis dürfen dann schön nach dem ü suchen, und Gurke können sie kaum aussprechen, ja die Forscher haben durchaus einen schrägen Humor).
Wirklich neu ist nicht, was in diesem Hörbuch erzählt wird, das meiste ist Geschichte der Genetik und Zeugs, was man schon in diversen ARTE Reportagen gehört hat. Leider fehlten mir da auch einige der unterhaltsameren Episoden, wie z. Bsp. woher die erste Drosophila Mutante kam, nachdem die Forscher die armen Viecher in dunklen Schränken eingesperrt und zentrifugiert hatte, ohne Effekte zu erziehen, weil Mutagene noch unbekannt waren, oder wie die ersten Maus Inzuchtstämme entstanden. Vielleicht steht es ja im Buch, im Hörbuch jedenfalls fehlt es. Ebenso ist es falsch, dass Arabidopsis thaliana keinen Trivialnamen hat, im Deutschen heißt das Laborunkraut jedenfalls Ackerschmalwand, der.
Jetzt, nachdem keine Prüfungen zu dem Thema mehr anstehen, ist das Thema Epigenetik gerade wegen seiner noch sehr idiomatischen Vielfalt sehr unterhaltsam, ich muss ja nicht jeden Namen parat haben und alles perfekt herunterbeten können und es dafür auswendig lernen was der Unterschied zwischen Angelman und Prader Wili ist (ja, Grabsteinbiologie auch hier), weil es keine Logik in der Namensnennung oder den beschriebenen Effekten gibt.
Insgesamt reicht das Hörbuch locker, um die Erstesemesterklausur Genetik soweit zu bestehen und wohl sogar einige der Dozenten mit exotischeren Beispielen über Meerschweinchengenetik zu verblüffen.
Der Sprecher ist angenehm, wenn auch nicht herausragend, aber für ein wissenschaftliches Sachbuch angemessen.

Edit: 2016
Streckenweise deutlich überholt, besonders das Kapitel über PTSD. Aber immer noch ein guter Einstieg in das Thema.
Profile Image for Kerry Cunningham.
17 reviews6 followers
December 5, 2014
I've read a good deal of the popular genetics stuff, and I've had a class in micro-biology, so I've had a pretty good base for this book. Even if I hadn't, though, I think this would be pretty accessible. I'm not a great judge of that, though.

One of the biggest surprises in recent scientific history was finding out that humans do not have an exceptional genome. The stuff that makes humans human is very similar to what makes everything else whatever it is. Our genome isn't necessarily bigger or more complex than other creatures. By and large, that is really good news, because it means that a wider range of other creatures are good laboratory proxies for humans -- from fruit flies to (very unfortunately) other great apes.

Epigenetics is part of the explanation for how a genome can be a (relatively) unspectacular as ours and yet produce spectacularly different beings. DNA are the letters in which the recipe of the genome is written, but there's more to it. Other chemical factors -- factors which can and are modified by experience -- moderate the function of DNA, such that two people with precisely the same genome can result in radically different phenotypic and behavioral expressions of that genome. In other words, identical twins may sometimes be very different from one another despite having the same DNA, because the factors that regulate how the DNA is transcribed can vary based on experience.

Having a stressed out mother can cause permanent changes in how genes are expressed in the mother's children, for example.

Most of the other popular works involving genetics, from books on cancer to books on evolutionary psychology, do not address the role of non-genetic factors (epigenetics) in the expression of genes. As such, this is a good addition to your library if you are interested in those subjects.
Profile Image for Candice Carpenter.
29 reviews14 followers
April 18, 2012
A great primer on the astonishing new developments within the arising field of Epigenetics. Beware, a solid background in college biology, genetics, and immunology is necessary to read this book with understanding. A definite recommendation for bio majors, pre-meds, and geeky non-science folks who like to dabble in science from time to time. But in a nutshell, what is epigenetics? Essentially, everything that happens on TOP of and AROUND our actual genes, or our individual genomes. For instance, genes can be turned on and off continually via methylation (e.g. spraying genes with methyl groups) or histone addition/removal (e.g. histones are proteins that tightly hug genes and keep them wound up in our cells).

For a sneak peak, I've included a few key themes of the book:

(a) Epigenetic gene regulation is long-term gene regulation; hence, epigenetic alterations have long-term effects on gene behavior.

(b)Environmentally induced epigenetic alterations that occur early in life are especially important. I.e. poor nutrition can epigenetically impact your genes for a lifetime or more!

(c)Epigenetic processes are predominantly random.

(d) Epigenetic alterations can have a transgenerational impact that is direct or indirect. In other words, what happens to the surface of your genes in your lifetime can be passed onto your kids!

Very cool book- definitely a quick and knowledge-boosting read.
60 reviews1 follower
April 11, 2021
This was an audiobook. Personally I think I would have benefited from having a print copy. The language used in this book is much like a textbook and at times it was a quite hard to follow.

I gave it three stars because I liked the way it makes Epigenetics accessible to those who haven’t spent their lives studying science. That said, I felt it stopped short - I would have liked to see more about the further practical application of Epigenetics and possible avenues for further research. The style of the book felt somewhat like a literature review.

I also felt this book was too in-depth in parts - this may just be me, as someone who isn’t particularly scientifically minded, however I found myself summing up each chapter in a sentence as we went along. It felt longer than it needed to be.

That said, the writer clearly knows their stuff and as a newbie to the field of epigenetics it did succeed in giving me a feel for the discipline.

40 reviews1 follower
January 4, 2018
This book has good introductory information about epigenetics, but there's lots of room for improvement in the book's organization and presentation of that information. One chapter spent a lot of time summarizing The Deer Hunter, which wasn't necessary in so much depth and gives away the ending of the movie. That chapter could have spent more time on the epigenetic phenomenon it describes and less on the summary. Near the end there also seems to be too much of a focus on pitting epigenetics against genetics. Overall, I'd say if you want a basic introduction to the topic of epigenetics, this book does a good job of raising several interesting topics within the field, so you can benefit from reading it, but the writing style leaves something to be desired.
Profile Image for Bruno.
100 reviews4 followers
June 11, 2019
There's some chance this may be the fault of the Brazilian translation I read, but overall I found the author too concise when explaining actual epigenetic mechanics, while spending too much time explaining tangential (at best) concepts to support each chapter (especially the 5 pages or so dedicated to summarizing The Deer Hunter). By the end, I couldn't say I really understood the basics of epigenetic (beyond methylation) or is relevance to humans (considering direct epigenetic inheritance seems to be mostly indirect in us). Maybe others would find this very valuable, I couldn't.
29 reviews
May 4, 2018
This is a fantastic book with lots of great information. It is advertised as being accessible to people who aren't scientists. While it is easier to read than a text book for someone currently enrolled in science courses, there is still a level of background knowledge needed to fully grasp all of this detailed information. Fascinating read!
Profile Image for Anthony Cleveland.
Author 1 book31 followers
July 18, 2017
Not for the nonscientist. I slogged through it because I'm interested in the topic. However, I think this one could be "redone" with the general population in mind to facilitate better understanding of an important topic.
Profile Image for Caroline.
600 reviews44 followers
April 14, 2022
When I went to the library to find out more about epigenetics, there were two books on the shelf, both 10 years old or so. I grabbed them both, and course to read the other one first because it seemed based on its presentation to be more directed at a general reader.

I should have read this one first. The books cover almost the identical territory - the Dutch famine of 1944-45, a study of rat development based on how much their mothers lick them, X chromosome gene inactivation - but for some reason I found this one more lucid. Francis seems to be less concerned with being clever, which I am sure helps. It's not that he doesn't have a dry wit - a biologist who worked in fetal development and then gave up biology for philosophy did so "to the detriment of both."
He begins with identical twins who have different versions of the same genetic condition - if all that matters is the gene, how can monozygotic twins differ at all? By the time he is done, he has thoroughly debunked the idea that genes are the executives that determine everything. The biochemical environment in which the gene functions determines how or if a given gene will actually be expressed. And our biochemical environment comes from both inside and outside us.

Which incidentally calls into question a lot of what passes for DNA testing for health. Yes, if you carry a gene for something that would lead to a fatal disease if you had a child with someone else who also carried that gene (the example I am most familiar with is beta-thalassemia), you should take this seriously. However, if you get a report that says you have a gene that is likely to indicate a predisposition to heart disease or kidney disease - that is only part of the story, because given the science of epigenetics, that gene may or may not actually be expressed/active in you specifically. (The fact that such findings are basically statistics - we found this gene in some percentage of people who had this disease - is a separate issue.)

Francis also talks about the models of fetal development that lead to such misunderstanding of stem cells - is fetal development just the unfolding of a human being who is there from the first second, as religious and anti choice people insist, or is it the creation of a human being gradually from almost nothing? He elucidates why the science does not support the first model.

As an aside - he says something I wanted Carey to say, but she didn't - the tests involving how much rat mothers lick their pups don't just generalize to humans (i.e. the mother is always to blame somehow), in part because rats are only parented by mothers - rat dads aren't a thing. At the end of his discussion of this topic he says that humans frequently are parented by a mother and a father and the effects of paternal nurture on development need to be studied. Thank you!

Epigenetics is of major importance for our understanding of health and also by implication of the reasons why some health problems persist in some populations. Hint: it's not inferior genes. This book is a good introduction, I hope we get a newer one soon.
Profile Image for Behrooz Parhami.
Author 10 books34 followers
August 19, 2024
The term "epigenetics" means "on the gene," the relatively recent discovery that stress and environmental factors can impact an individual's psychology so deeply that the resulting biological "scars" are potentially inherited by multiple generations that follow. For example, men who start to smoke before puberty increase the chance of obesity for their sons. Epigenetics is now believed to hold the key to understanding not just obesity, but also diabetes, cancer, Alzheimer's, schizophrenia, and autism.

Epigenetics has established beyond any doubt that while genes are quite important, they are subject to regulation by forces that can turn them on or off, sometimes for a lifetime or even across generations. Epigenetic changes are above and beyond longer-term changes due to random mutations and natural selection.

This first general introduction to epigenetics is driven by many stories such as the Dutch famine of World War II, Jose Canseco & steroids, breeding of mules & hinnies, Tasmanian devils, and contagious cancer. Each chapter in the book starts with an entertaining or intriguing example of how epigenetics affects human and animal biology and inheritance, followed by detailed discussion of the mechanisms at work.

The Dutch Famine of the mid-1940s is an example. When, near the end of World War II, Germans were retreating from Eastern Europe, they decided to punish the Dutch resistance by destroying much of their infrastructure and flooding their agricultural fields. The ensuing famine led to ~20,000 deaths and had other devastating effects on the population, particularly, on pregnant women, whose malnutrition led to deficiencies in their babies and multiple subsequent generations. The Dutch kept meticulous health records, which allowed detailed studies of the effect of the famine and jump-started the field of epigenetics. Such large-scale human experiments are nearly impossible to plan, given limitations on the use of human subjects.
Profile Image for Dan'l Danehy-Oakes.
717 reviews14 followers
December 16, 2019
This 2011 book is doubtless somewhat out of date, but I doubt that it has been supplanted as an introduction for the general reader.

Epigenetics, for those not hip to the biology jive, is the study of biological inheritance that doesn't come directly from DNA. The classic example of this is gene suppression by methylation, but (as it turns out) this isn't the whole story.

The very different cells in the human body all have the same DNA and therefore the same genes. And, when a zygote first begins to develop, its cells are for all practical purposes identical to one another. It is their physical relationships to one another that determines how they develop, into skin cells, muscle cells, neurons, or what-have-you.

Francis describes the mechanism of these and many other things (like why your grandmother's living through a famine can effect your weight problems today, or why identical twins aren't really) in sufficient detail that the lay reader like me can have the illusion of understanding complex ideas. Indeed, we _do_ understand them at, at least, a low level. I couldn't tell you how to methylate a gene if my life depended on it, but now at least I know to a good approximation what it means for a gene to be methylated.

The writing is clear but often quite dense, requiring a ponder between (and sometimes even during) sentences. Another way of saying that is that this book is information-dense, and therefore a bit of a slow read. It took me nearly a week to get through its 160 pages.

Recommended for curious people who aren't afraid of lots of details.
182 reviews119 followers
May 16, 2014
A Great Introduction to Epigenetics, but...,

Review

When I was but a young man, so many moons ago, I used to delight in annoying my oh-so enlightened scientistic brethren by doubting that the current Darwinist Settlement (Blessed be Its Name!) had given a final account of evolution. I leaned in the direction of some sort of Lamarckian materialism, of course never really settling on the physical mechanism of cultural-inheritance because there were no obvious contenders.

By 'cultural inheritance' I meant back then that behaviors and events in parents lives could somehow influence and even change the genes they passed on to their children and their childrens children. What made me think this likely was all the anomalies that Darwinism (as then understood) could not explain. (For those interested, Rupert Sheldrake has, in his many books, detailed them quite exhaustively.) I am now quite satisfied that Epigenetics, this latest addition to the Darwinist understanding, will eventually take that mountain of anomalies and turn it into a mound. God, how I hate toeing the party line! But even those who merely repeat received wisdom are not always wrong... Dammit.

So, what is epigenetics? Well, there are genes, and then there is the material that surrounds the genes. Epigenetics studies how this material influences (the correct term is 'expresses') the genes. The material "can alter the behavior of the genes to which they are attached; and they can cause genes to be more or less active." And this influence can even (in certain rare circumstances) be passed on for several generations. ("... epigenetic states, some environmentally induced, can be transmitted from grandparent to grandchild.") So you see, Lamarck was right; there is some sort of heritability of acquired characteristics. But the Darwinists were right too; these epigenetic changes do not effect the genome itself and eventually evaporate, like a surging river inevitably disappearing into some endless, feckless desert it had so blindly sought to cross.

So No. Epigenetics is not Lamarckian; but all intelligent Larmarkians (imho) will eventually accept epigenetics, - and therefore Darwinism!

This is a very good first book to read on the subject of epigenetics. But I agree with the reservations of earlier reviewers. It is very anecdotal and I am certain that anyone with a background in biology will find it rather thin. After reading this book I am not sure I understand the mechanisms of epigenetic change fully. But I am sure there will be more books to come. Four stars for an excellent introduction. But where does one go next?

Speculation

While reading this book I was struck by the notion (I should rather say 'the fear') that epigenetics will one day be used as a means of population control. I had always thought and hoped that no government would use genetic manipulation to control the behavior of people because of the risk involved. What risk? The world is no longer as safe as the scientific uniformitarianism and gradualism that was commonly taught when I was young assumed. The comet Schumacher-Levy 9 twenty years ago was probably the nail in the coffin. We are all, to varying degrees, neo-catastrophists now.

Why would any government monkey with the Human Genome? Well, any change through genetic manipulation would obviously be done to make the populace more obedient and useful to the powers that be. The only parameters to this manipulation would be that the people must be fit enough to reproduce themselves and continue to work in order to produce material civilization. So you see, not every genetic manipulation would be useful. People must have babies and go to work.

In my judgement it is a good thing that old myths that no longer serve any purpose die. Uniformitarianism and gradualism were but scientistic fairy tales. They assured us that we could both know everything (I mean by this a 'Theory of Everything') and that we would always have time to react to some unexpected change in the natural world. We now certainly have reason to doubt the latter... (I doubt the former too, but that is another review.) Besides the real danger of asteroids and comets, recent work in climate change throughout prehistory shows how terrifyingly fast climate change can happen.

For those of you who remain committed uniformitarians and gradualists I will point out that only a couple of weeks ago (3/26/2014) the discovery of a 'dwarf planet' (2012 VP113) in the Oort cloud was publicly announced with an orbit inexplicable by our current understanding of the greater solar system. When I was young the solar system was a simple thing: rocky inner and gaseous outer planets. (Pluto was something of an anomaly, later resolved.) Now, we have inner and outer planets, the Kuiper belt, and the Oort cloud. And of this last we know fleetingly little. One of the possible explanations for the orbit of 2012 VP 113 is there may be, somewhere in the Oort cloud, a planet (or planets!) to rival the size of earth! Of course, there are other explanations. As our technology improves, we are certainly likely to find other dwarf planets outside of the classical solar system with long period eccentric orbits. Any one of them could be a potential threat.

So you see, neo-catastrophism really does seem now to be our fate. And because of this I serenely thought that genetic manipulation was off the table as a means of controlling populations. Why? We know that the human species in pre-history survived catastrophic events. Change our genetics base, for whatever reason, and one could not be certain this would be true in a catastrophically altered future. Every change has unexpected and unwanted consequences. This would also be true of any and all supposedly 'useful' changes to our genome.

But I fear that epigenetics changes all that. In radically changed conditions, any previous epigenetic manipulation of humanity would disappear quite rapidly in those radically changed conditions. I fear that the elites who rule the world, and intend to continue to do so, have noticed this.

...And I fear for the future.
Profile Image for Jina.
246 reviews1 follower
March 28, 2018
From what I understand, Epigenetics is a huge topic, and Richard C. Francis trimmed it down to the basics. I think Francis accomplished his goals for this book. He produced a piece that is easy to read for the general public, and provided an introductory level of information without all of the fluff. He also encourages his reader to seek out the sources in his notes, particularly if something he mentioned interests them - fully acknowledging he’s just brushing the surface on these topics. However, I felt like the author occasionally spent a bit too much time creating detailed context for things that weren’t necessary - such as describing the entire plot of the movie Deer Hunt. The flow from chapter to chapter also felt a bit weird the further into the book you got. Otherwise, I enjoyed reading this book. I appreciated the overall summary “Postscript” at the end, though. It really helps a general public reader walk away confidently about what they learned.
Profile Image for Sierra.
5 reviews
June 26, 2024
A decent jumping off point for people who are beginning to learn about epigenetics. I do feel that the author focused a little too much on trying to avoid jargon or get too complicated. The amount of real world anecdotes was a bit much. Sometimes they were warranted and related nicely to the topic, and other times it felt like they were just there for the sake of it. One instance bothered me the most, which was when the author went on a tangent about a film. There is no need to spend pages describing a film that has very little to do with the topic (and a film that a lot of readers probably haven't seen), when the concept could've been explained so much more simply. There were a lot of interesting research studies mentioned and I think this book could have been stronger if it focused more on those studies instead of trying too hard to make things palatable.
Profile Image for Paul Noël.
Author 18 books2 followers
June 29, 2020
The book is an excellent introduction and makes the subject interesting to the non scientific reader with the author's varied selection of examples illustrating what he wants to put across. I vaguely remembered some of the genetics that I studied many years ago. Having been written in 2011 the amount of research carried out and being carried out on epigenetics is phenomenal so for anyone interested in this field it would be good to follow up reading this book with something more recent. It's a great book for wetting your appetite for this exciting field of science.
Profile Image for Tom.
371 reviews
September 8, 2011
This book is an excellent introduction to the field of epigenetics. This area is going to help define the biological framework on which will be built a more comprehensive medicine. It is providing the important linkage between environment (physical and psychological)and physiological outcomes that can be transgenerational.

Notes:
The Dutch famine of WW II provided a natural experiment on the effects of maternal nutrition on fetal development. The Dutch Famine Birth Cohort Study is ongoing and studies the multi-generational effects of the famine. Not surprisingly birth weights were lower among children born during the famine. Less obvious was that as this cohort of children became teenagers and eligible for compulsory military duties in the 1960s they were found to have significantly elevated levels of obesity, roughly double the rate of those born before or after the famine. This effect was most obvious in those who were in the first or second trimester during the famine. Further, there was found a significant increase in the incidence of schizophrenia and depression among those exposed prenatally to famine. Among males there was an increased risk of antisocial personality disorder. By 50 years of age, those affected had higher rates of hypertension, diabetes, coronary disease. The effect varied with the point in the pregnancy when the exposure occurred. First trimester-inc’d obesity, coronary disease and breast cancer. Second trimester-lung and kidney problems. third trimester-glucose intolerance.

Environment affects our genes indirectly, by affecting the cells. Any environmental effect is cell specific. Epigenetic gene regulation occurs through methylation=the attachment of methyl groups to genes, which decreases or down regulates gene action.

In studies of the Dutch famine it was found that the gene that codes for insulin-like growth factor (IGF2) was more methylated, hence less active, in those exposed to the famine in utero.

Most epigenetic attachments are removed during the production of sperm and egg cells and hence not passed on. The fertilized egg begins with an epigenetically clean slate. Most-but not all. Even the children of those who experienced the famine while in their mother’s womb are more prone to ill health later in life.

Intracellular transcription factors act upon the control panels of genes to stimulate protein production. Hormones such as anabolic steroids effect their influence through the presence of androgen receptors in cytoplasm. Cells differ in the presence or absence of such receptors, so the influence of these hormones varies from cell type to cell type.

Gene expression is influenced by surrounding cells, and, as well, distant cells that exert their influence through hormonal changes. Even social interactions are in important source of gene regulation. The outcome of competitive activities, for example, alters androgen levels, and they, in turn influence cell function and gene expression. [the biological basis of transgenerational, racial and ethnic ‘characteristics’ are being laid down in epigenetic research]. ‘To the extent that psychiatric interventions can meliorate the psychological effects of traumatic events…these interventions will cause alterations in the regulation of genes in [the] brain.”

Trauma, both physical and psychological can induce epigenetic changes leading to long-term alterations in gene regulation. The stress response is important to our vital functions as it represents the attempt to keep things in physiological equilibrium. When reference is made to problems in the stress response, usually this pertains to one of two ways in which it can go awry: the stress response can be overly sensitive, easily triggered and chronically overactive leading to anxiety and depression. The second way is to react too robustly to a stressor leading to ‘blowing the circuits’. The way in which we respond to stress is heavily influenced by the prenatal environment. For example in the past cortisol was given to women in premature labor to speed up the maturation of fetal lungs. It has been found that the children exposed this way in utero are predisposed to anxiety disorders, depression, substance abuse and schizophrenia. Similarly, if pregnant women are under severe stress, they too release cortisol which can affect the fetus. Such stress could be a bad marriage, social isolation, or poverty. Children of mothers who suffered PTSD in the Holocaust themselves are more prone to depression. Experiments with guinea pigs demonstrates a direct relationship between maternal care and the stress response as manifest in glucocorticoid receptors in the brain. This results in greater negative feedback sensitivity to cortisol and hence reduced levels of cortisol releasing hormone (CRH). Good mothering (at least in mice) promotes the demethylation pathway whereas poor mothering results in greater methylation, resultingin fewer GR proteins in the hippocampus. This causes the stress axis to be more hyperactive, predisposing to anxiety and fearfulness.

There is an excellent chapter outlining the differences between two theories of cancer: somatic mutation (SMT) and the aneuploidy theory. An epigenetic view is then introduced that pays more attention to the local cellular environment-the microenvironment. This helps to explain the return of some cancer cells to normality-cases of spontaneous regression. This chapter deserves a careful re-read.
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