The Epigenetics Revolution: How Modern Biology is Rewriting Our Understanding of Genetics, Disease and Inheritance

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Three different epigenetic mechanisms have been identified: DNA methylation, histone modification, and non-coding RNA (ncRNA)-associated gene silencing. Catalyzed by DNA methyltransferase enzymes, DNA methylation involves the addition of a methyl group directly to a cytosine nucleotide within a cytosine-guanine sequence (CpG), which are often surrounded by other CpG’s forming a CpG island. CpG islands are common targets for epigenetic DNA methylation, notably the CpG islands within promoter regions. Indeed, it has been reported that around 70% of gene promotor regions lie within CpG islands. [13] Methylated cytosines within a promoter region recruit gene suppressor proteins and reduce interaction between the DNA and transcription factors. [14] Cytosine methylation also drives the formation of heterochromatin, so the nucleosome tightening prevents transcriptional machinery from interacting with the DNA. [15] As such, DNA methylation within promoter regions results in gene silencing. Cancers often show marked hypermethylation of tumor suppressor genes and hypomethylation of proto-oncogenes, both of which contribute to tumor carcinogenesis. [15] This epigenetic mechanism also plays an important role in tissue-specific gene regulation, genomic imprinting, and X chromosome inactivation. [14] It explores the impact of non-genetic factors, such as nutrition, exposure to chemicals, and other environmental factors on human gene expression. The author, Trygve Tollefsbol, manages to include the most recent discoveries in the field of epigenetics, starting by covering the basic aspects, explaining the newest technologies, their effects on clinical medicine, and more. New Epigenetic Discoveries The book’s main aim is to provide a framework that can be implemented for the purpose to understand the basic notions of epigenetics, and to distinguish the area of epigenetics as a separate part from genetics, seeing it as an independent discipline. Additionally, the book serves to highlight the important role of the organization of genetic material itself and its distribution throughout the cell’s biochemical environment. Epigenetics is, as the title claims, the study of how our genes interact with the environment around us. This new subfield of Geneti The DNA double helix wrapped around four histone proteins, in a structure called a nucleosome. By Richard Wheeler (Zephyris) [CC-BY-SA-3.0]]/Wikimedia Commons Photograph: Wikimedia

Epigenetics is a relatively new researched area that belongs to the field of genetics, but the gathered evidence of its importance is tremendous. Handbook of Epigenetics is one of the most popular epigenetics books, a collection of 37 articles, mainly concerned with the biology of epigenetics. Epigenetics is a scientific field that has been increasingly developing over the past 20 years or so. It is concerned with the changes of gene activity that are not dependent on the gene sequence, more specifically, how the environment plays a key role in the structuring, or possibly restructuring, of your genotype. Epigenetics is an emerging frontier of science that involves the study of changes in the regulation of gene activity and expression that are not dependent on gene sequence and it is in "The Epigenetics Revolution" by Nessa Carey where you will be introduced to a fantastic world of science in which you will learn if and how environment play a fundamental role in your genotype/phenotype. Nessa Carey is an active researcher, and an excellent writer. She explains cogently why there certainly is a "revolution" occurring now in genetics, and gives us a very good introductory guide to the subject of epigenetics. There is much more to genetic inheritance than simply the "DNA" that is found in our cells. Carey shows many examples of epigenetics at work. One very basic example is the fact that despite every cell nucleus having "identical" DNA, our cells specialize for each organ in the body.

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There have been lots of popular science books about genetics and evolution, and that's fine - but there really hasn't been anywhere near enough coverage of epigenetics, which is why Nessa Carey's book is so welcome. Over the last 30 years or so it has become increasingly obvious that the idea of genes coding for proteins - the basic concept of genetics - is only a starting point for the way DNA acts to provide control software for the body's development. There is also RNA that is coded by 'junk' DNA and the way genes can be switched on and off by various external factors - all together this is far more than genetics alone. This is epigenetics. We've all read that we lose almost all our cells every few years and replace them with new ones. Well, not so fast. A huge exception to this is the neurons in our brains. They pretty much last us a life-time. Why and how?

DNA --> mRNA --> proteins --> you understand life! Well, it was never that simple but now it's not even an accurate description of all the functions of DNA. Genes exist in binary "off or on" states. Wrong! Many genes effectively have dimmer switches that allow a continuous spectrum of activation from fully off to some maximum rate of expression. 98% of our DNA is "junk." Wrong! Only 2% codes for proteins but various parts of the rest are now understood to serve several functions, from acting as the above mentioned dimmer switches, to coding for types of RNA that serve functions other than being an intermediary in protein production, including suppressing cancerous changes in cells. Things that happened to your parents or even grandparents can affect your phenotype, e.g. how prone you are to obesity. Perhaps the most studied clinical application of epigenetic mechanisms is cancer. One of the first reports of epigenetics involved in cancer reported hypomethylation of DNA in cancer cell genomes, which caused overexpression of genes within that cell. [26] Since this report, great strides have been made toward understanding the role of epigenetics in carcinogenesis. For example, the degree of DNA methylation continues to decrease as a benign tumor cell progresses to invasive cancer. [27] Other studies have shown hypomethylation of pro-proliferative genes like BAX2 that are suppressed in normal cells. [28] Other reports show hypermethylation of tumor suppressor genes, like Rb, BCRA1, and CDKN2A, in cancer cells. [29] [30] [31]Despite the wealth of knowledge present on the relationship between epigenetics and carcinogenesis, treatment development is still very much in the preliminary phase formost cancers.This book is interesting and notably competent science writing. The proper audience for this book is someone with specific interests in genetics, and biology. We’ve all heard stories of people who experienced seemingly miraculous recoveries from illness, but can the same thing happen for our world? According to pioneering biologist Bruce H. Lipton, it’s not only possible, it’s already happening. We are surrounded by the proof that we are poised to take an incredible step forward in the growth of our species. In Spontaneous Evolution, this world-renowned expert in the emerging science of epigeneticsteams up with political philosopher Steve Bhaerman to offer a new and hopeful story about humanity’s evolutionary destiny. Recent discoveries about the working mechanism of genes revealed a completely new approach to understanding the origins of our phenotypic characteristics. The developing Genome serves as a great introduction to epigenetics, explaining how our experiences influence the change in our genes, and the way they function, listing a variety of factors that impact those changes, some of them being food and drinks, pollution, and other environmental toxins, parenting styles, etc. The author, David S. Moore proves that epigenetics changed and continues to change how scientists think about nature and human development in general. Epigenetics for Dummies

Carey goes into a detailed presentation of how your epigenome may change based on the type of foods and drinks you consume, whether you smoke or not, the type of medicine you take and the pollutants you’re surrounded with. She provides examples of both healthy and unhealthy lifestyles and includes illustrative material on the possible organs and mind damage, which make it easier for the reader to see the environmental influence more directly. Armstrong provides the reader with a strong essence of each subject and area in the book by giving well-explained and detailed introductory sections. The number of topics this book covers allows the reader to obtain not only general knowledge but also a more detailed understanding of how epigenetic mechanisms work, the changes they trigger, as well as the consequences of those changes.Overall, I would definitely recommend this book for anyone interested in anything biology related! It is a challenging, but really interesting read, and perhaps, as it did for me, it will change the way you think about biology! Studies of humans whose ancestors survived through periods of starvation in Sweden and the Netherlands suggest that the effects of famine on epigenetics and health can pass through at least three generations. Nutrient deprivation in a recent ancestor seems to prime the body for diabetes and cardiovascular problems, a response that may have evolved to mitigate the effects of any future famines in the same geographic area. The material this book presents is well-organized, comprehensible, and easy to understand. Epigenetics by Armstrong also provides a graphical presentation of the complexities of epigenetics and includes information about all aspects of the subject, proving this book to be a valuable source for students, professionals, and anyone who likes to delve into this complex topic, making it among the best ones this epigenetics books review has to offer. Economic meltdown … environmental crisis … seemingly endless warfare. The world is in critical condition. 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.

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: I found this to be an enjoyable book, written in an engaging style which draws the reader into each chapter. It contains a lot of information, some quite detailed. Although I'm a scientist by profession, this was a new area for me and reading this work has taught me a lot about epigenetics and its importance in the functioning of life. Much of the material was very thought provoking and eye-opening. One hallmark of these modifications and probably the better understood so far is DNA methylation which affects your genome. Methylation simply means the addition of a methyl group at cytosine, which is the only of the four DNA bases that gets methylated and more specifically at the C's that preced G's in the DNA chain and form what we refer to as CpG dinucleotides or "islands" when there are high concentrations. Once DNA is methylated it bind to a protein called MeCP2, then these methyl groups turn genes off by affecting interactions between DNA and the cell's protein-making machinery such as gene promoters, transposons and imprinting control regions. In the following picture you can see how MeCP2 binds to a gene promoter attracting other proteins to help switch the gene off:It is an extended essay explaining how environmental factors affect our genes but do not trigger changes in our DNA sequence. Francis argues that genes do not always have all the control, but work under influence of the biochemical environment of the cell. What Else Can Epigenetics Affect? Now that I’ve piqued your interest in this fascinating field (and maybe that of your unborn children. Epigenetics!), in my next piece I’ll explore the role of epigenetic changes in the onset of cancer and other diseases, and what this means for the development of new treatment options. As if the vagueness in the debate of the priority of genes or education was not complicated enough now, with the influence of technology, nutrition, mental health, and general living environment, a third pillar is added. How strong influences on human evolution will likely be is influenced by various factors, such as how active the genes are and how susceptible a human being is for the effects of education or the tribal culture around him. There are other things I can strongly recommend about this book. It is well referenced, so if you're inclined to look up the technical details and verify what Nessa is saying, you can. Nessa is mostly presenting work that is not controvercial today, even though it is radical by standards of the end of last century. When she does talk about matters that are still murky - when there is still no consensus today - she tells you. She also isn't on a giant self-promotion exercise for her own theories, as many pop sci writers are. All of this makes her trust-worthy in my eyes, in stark contrast to many pop sci authors. 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.