The Epigenetics Revolution: How Modern Biology Is Rewriting Our Understanding of Genetics, Disease, and Inheritance Paperback – Illustrated, October 1, 2013

This book is interesting and notably competent science writing. The proper audience for this book is someone with specific interests in genetics, and biology.The word, “epigenetics” refers to all those ways in which influences are imposed on the genetic codes in DNA in our cells. Unfortunately, as Nessa Carey reminds us on page, 101, the word has been used in many different ways, and therefore a book on epigenetics ends up resembling a book called, “Many Topics About Genetics and Biology.” One of the strong points of this book is the author’s determination to provide the reader with a text that is thorough and up-to-date, and one of the problems with this book is the shotgun, or smorgasbord effect of trying to cover many topics related by an abstract concept, but not necessarily very similar to each other.This book consists of sixteen chapters, each one of which deals with a particular cellular phenomenon in which the genetics of DNA is superceded or modified by some other effect. For example, in Chapter Two, the author discusses cell differentiation, why the cells in our body all contain the same DNA but make different tissue types. In Chapter Five, the author discusses, “Why Aren’t Identical Twins Actually Identical.” She points out that identical twins, who have exactly the same DNA sequences in their chromosomes, are not necessarily concordant for genetic diseases such as schizophrenia. She reminds us that the DNA occurs in a kind of “dampening field,” something like a dimmer switch or a volume dial, which determines whether and how the DNA code gets expressed. In Chapter Six, called, “The Sins of the Fathers,” Carey describes how in some exceptional circumstances, environmental influences can be passed across the generations as if our genes could learn, the kind of thing that Lamarck promoted, and that has generally been disproven by modern genetics, but which occasionally pertains, for example the way starvation during warfare can influence subsequent multiple generations.In Chapter Eight, “The Battle of the Sexes,” Carey takes us through the remarkably complex stages by which our father’s and our mother’s chromosomes can be coordinated when they form a single new entity. In Chapter Nine, the author discusses the complexity involved with the fact that males have only one X chromosome, while females have two X chromosomes, one of which is a duplicate that therefore needs to be shut off. The silencing of one X chromosome in every cell in every woman, and the asymmetry of chromosomes in every male (who have one X chromosome and one Y chromosome instead of a pair of chromosomes) and the possibility for errors in these mechanisms, opens a pathway to interesting speculation about important social issues, such as the biology of gender, or sexuality, issues which the author chooses to refrain from considering in this cautiously scientific book.My favorite chapter was Chapter Ten, “The Message is not the Medium,” in which the author does an outstanding job of authoritatively dismissing the widespread, misguided idea that DNA codes for protein, and that DNA which does not code for protein is therefore “junk.” She shocks the reader with the dramatic statement that the complexity of living organisms correlates better with the percentage of the genome that does not code for protein than the percent that does. Organisms become more complex, evolving from bacteria, through mice, through humans, not by creating more proteins, but by regulating proteins with greater complexity. At a certain evolutionary point, proteins have become refined, and mutually fitted to the extent that few modifications to them can become adaptive. At this junction, most protein modifications create errors and problems; therefore, from this evolutionary point onward, for organisms to adapt and evolve, few future changes in protein structure can be made, and instead, the way in which proteins can be regulated becomes a new avenue of selection and adaptation.Carey guides us through detailed descriptions about how the genome is regulated through various methods, such as methylation, acetylation, histone changes, and most remarkably, the way that DNA codes non-coding RNA, which in turn regulates DNA. DNA itself creates RNA molecules that act like dial-turners or button pushers, augmenting or reducing DNA expression. Only two percent of the human genome codes for the manufacture of protein. “The fact that ninety-eight percent of the human genome does not code for protein suggests that there has been a huge evolutionary investment in the development of complicated non-coding RNA-mediated regulatory processes…Complicated networks of molecules influence how, when and to what degree proteins are expressed.”Another example of Nessa Carey’s carefully documented, stereotype-busting writing, is her emphasis that, “Cancer is not a one-off event. Cancer is a multi-step process.” She points out that women who inherit a mutated BRCA1 gene, are at high risk for breast cancer, but do not necessarily get cancer because other defects have to accumulate as well. We are reminded that cancer is not an entity, but a compounding of replication errors, environmental assaults, viral parasites in nucleic acid, and unbalanced patterns within our inbuilt flexibility systems that are intended to give varying permissions to stem cells’ full potentials. Much of our life is not driven, but poised, and its regulators are multiple.The thing I enjoyed most about The Epigenetics Revolution was Nessa Carey’s uncompromising attitude towards the complexity, multiplicity, and unexpectedness within the mechanisms that regulate genes. What I enjoyed least about this book is the attempt to cover too many topics, some of them only tangentially related to others. This book has useful charts, illustrations, and meaningful cartoons. Another excellent feature of the author’s style is the emphasis on science as a living and personal process. The book recounts many experiments and counter-experiments and familiarizes us with the human side of scientific dialogue and argument.This book is more interesting than pleasant, more arduous than easy, and it is not for the average reader, but I constantly felt like cheering for the excellence of Nessa Carey who is so determined to bring to our attention the wonder of genetic inventiveness within our life.Review by Paul R. Fleischman author or Wonder: When and Why the World Appears Radiant

One reviewer on the back cover said that Nessa Carey's "book combines an easy style with a textbook's thoroughness....A bold attempt to bring epigenetics to a wide audience." While it is an easy style, it is not an easy read. It becomes very technical in some parts. Her writing is seasoned with occasional light-hearted quips and plenty of interesting narratives. Maybe her book could have been made more user-friendly for the layman if she had put the very technical material in appendices and kept the warm, friendly chats in the main text. Such a tactic might help the less-technically-minded reader peruse her book if her intent was to capture a wide audience.Is it possible that acquired characteristics can be inherited to the third, or even the fourth generation? Carey thinks so. She quotes Exodus 20:5, "For I, the Lord your God, am a jealous God, punishing the children for the sins of the fathers to the third and fourth generation of those who hate me Exodus," as a segue for chapter 6, "The Sins of the Fathers." She assures the reader that acquired characteristic can be passed on to several generations of offspring. In a narrowly defined sense, Lamarck was correct. Biology professors taught me that Lamarck was wrong, that acquired characteristics were not passed from parents to offspring, and that all inherited traits were based strictly and squarely on DNA.Nessa Carey insists "that for some very specific situations Lamarckian inheritance is taking place, and we have a handle on the molecular mechanism behind it." (p. 110) The mechanism of epigenetics involves the methylation of DNA or histones. Methylation involves the attachment of a methyl group (-CH3) to the target molecule. There is also acetylation, phosphorylation, and other chemical modifications of DNA or histones that moderate the activity of genes.On her website, Carey explains epigenetics this way:"Every time we see two things which are genetically identical, but which aren't the same, we're seeing epigenetics in action. This affects huge amounts of life on earth and has a big impact on human health. The science is weird, heretical and fascinating."You have probably heard, "You are what you eat." In the case of honeybees, this is undoubtedly true. Carey explains how queen bees become queens and how worker bees (also female) become workers. She says that a virgin queen mates with several male bees (drones) before settling down to produce a hive of new bees. The drones usually come from other hives and very seldom from the same hive as the virgin queen. Nevertheless, a hive contains thousands of genetically identical bees. (p. 283) Of course, there are thousands of others that are genetically different from the group that is identical. Nevertheless, how does a larval bee become a queen rather than a worker?Dr. Carey explains that young worker bees (nurse bees) feed all honeybee larvae royal jelly for the first three days after hatching. After that time, nurse bees feed royal jelly to only the larvae that are to become queens. She says that no one understands why the nurse bees continue to feed royal jelly to only a few of the larvae. Who decides which larvae should become queens? Maybe there is some genetic or epigenetic tag that clues the worker bees. Carey doesn't suggest this.The pattern of early feeding completely deter¬mines whether a larva will develop into a worker or into a queen.This scenario "just SHRIEKS epigenetics," remarks Carey [emphasis added].I thought her discussion about rat babies who received much maternal care vs. the babies of mother rats who were lackadaisical at licking and grooming was very interesting. The well-nurtured babies became well-adjusted, calmer adults, while the less-nurtured babies became stressed-out adults. Carey describes several experiments that rule out purely genetic and psychological outcomes of maternal care. One might suppose that giving a juvenile rat a nurturing environment might improve the laid-back response to stress, but Carey leaves no doubt that good nurturing during the first week of a rat's life causes epigenetic changes. She said that "being licked and groomed by the mother set off a chain of events that led to epigenetic changes in the cortisol receptor gene." (p. 241)She explains how experimenters determined this. For instance, baby rats that had nurturing mothers were switched to lackadaisical mothers after the first week of life. These babies still displayed the calmer, laid-back traits when subjected to stress as adults. Babies of lackadaisical mothers were switched to nurturing mothers, and they became stressed-out adults.Dr. Carey examined the relationship between various diseases and epigenetic events. Is it possible that cancers could be cured if the right promoter regions of genes were methylated or demethylated? She explains that trying to prevent cancer via epigenetic modification could create worse problems for the patient. Even using epigenetics to promote longevity might actually cause cancer and early death.The relationships in genetics and epigenetics are finely tuned, and as a creationist, I see the interdependent relationships as indicators of God's handiwork. Carey sees the same things as products of a long process of evolution.Carey, like most evolutionists, believes that evolution produced the epigenetic systems. Presumably, because her book is about epigenetics and not evolution, she doesn't back up her occasional claims that epigenomes evolved. On the other hand, Thomas Woodward and James Gills claim the epigenome was designed in their book The Mysterious Epigenome: What Lies Beyond DNA.