Reviews for Identically Different : Why We Can Change Our Genes


ForeWord Magazine Reviews 2013 - Fall Issue: September 1, 2013

With British humor, this professor cites cutting-edge twin studies to investigate causes of differences.

The nature vs. nurture pendulum has swung toward genetic predetermination in recent years, with much-hyped searches for (and often, announcements of) gay genes, obesity genes, alcoholism genes, and more. Tim Spector's book Identically Different looks to set the record straight by explaining science's current understanding of the roles of environment, genetics, and a third hybrid factor, epigenetics.

Spector is about as well-qualified on these topics as any author could be--he's a professor of genetic epidemiology who set up the TwinsUK register in 1995, which continues to provide valuable data on genetic heredity. He's also been quoted often in the media and has appeared in television documentaries.

The title, Identically Different, mainly refers to Spector's studies and numerous examples involving identical twins. The book is filled with fascinating, often mystifying, real-life cases of twins separated at birth who exhibit strikingly similar or dissimilar characteristics later in life, or twins raised in seemingly similar environments who differ radically as adults. In each case, Spector probes into the genetic and environmental causes of these differences.

Aside from bringing readers up to the cutting edge of scientific knowledge on these subjects, Spector does an excellent job explaining epigenetics (the influence of environment on genome modifications, and how and when genes are expressed). Here, too, Spector has amazing examples at hand, including illustrating how the diet of a mother can impact the health and physical makeup of not just her children but also her children's children.

Epigenetics explains much of what's missing in the genes vs. environment debate, but Spector carefully parses just how much is yet unknown. In a chapter discussing talent, he challenges the "genetics" argument that Kenyans and Ethiopians make better long-distance runners and suggests that motivation, not purely physical attributes, seems to be the primary factor in determining athletic and intellectual success. Then, in an admission to how complex these matters are, he concludes that "the key motivation factor is again likely to be a mix of genes and environment." The book's subtitle, Why We Can Change Our Genes, is clarified when Spector explains that not only is true genetic predetermination rare but that the choices we make today can indeed affect not just our own genes but those of future generations.

The book is broken into concise chapters with titles like "The happiness gene," "The parenting gene," and "The fat gene," written with occasional bits of British humor that mostly hit the mark. Spector's interesting examples may have readers noticing finger lengths (tied to testosterone exposure in the womb) and checking the plastic bottles they drink from (exposure to BPA, a chemical in many plastics, has been tied to a host of health problems). Identically Different cuts to the heart of what makes us the way we are.

2013 ForeWord Reviews. All Rights Reserved.

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Kirkus Reviews 2013 June #1
Genes dictate our anatomy, emotions and behavior, except when they don't, according to this ingenious account of how inheritance and environments--including our parents' environment--vie to make an individual. Physician and TV commentator Spector (Genetic Epidemiology/King's Coll. London; Your Genes Unzipped, 2003) fills his book with entertaining anecdotes of identical twins (he is director of the world's largest twin registry) and examples from popular culture to make a convincing case that inheritance is more complicated than we think but no less fascinating. The idea that genes make us what we are ruled for half a century, until the 1960s, when a revolutionary generation insisted that our environment makes us what we are. Nowadays, scientists agree that both have an influence, but Spector cautions that DNA does not hardwire our lives. It turns out that actions can physically alter genes and that--despite what we learned in biology class--we can pass acquired traits to our children or even grandchildren. This process, epigenetics, means, for example, that a person who overeats transmits the risk of obesity for several generations. Genetics turns up in surprising places. Identical twins raised apart have remarkably similar personalities, sharing qualities such as optimism, empathy and a sense of humor (or lack thereof). Environmental factors also deliver plenty of surprises. Most readers will squirm to learn that upbringing exerts remarkably little influence on how children turn out. They are far more likely to emulate their friends than their parents, however competent and loving. Abusive parents are a different matter; crime, abusive behavior and mental illness have a disturbing tendency to run in families. A delightfully thought-provoking overview of the nature-vs.-nurture debate. Copyright Kirkus 2013 Kirkus/BPI Communications.All rights reserved.

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Publishers Weekly Reviews 2013 June #1

Spector, a genetic epidemiologist, has a wealth of case studies to draw from for his research on genes and epigenetics (the mechanism by which nongenomic elements affect genes): he's the founder and director of the TwinsUK registry, home to data on over 12,000 pairs of twins. He's spent the past two decades studying genetically identical siblings; for 17 of those years, he ascribed to the "gene-centric" view of things. But he felt like he was "missing something." That turned out to be the concept of "acquired inheritance," whereby environmental, hormonal, or other external stimuli modify one's genetic makeup. Perhaps the most interesting consequence of this is that such an altered blueprint can then be passed on to future generations. But drastic changes can occur even within one's own lifetime. For example, a cabdriver in London is subjected to intense route training in order to navigate the city's intricate streets; as a result, his hippocampus--a part of the brain that deals with spatial navigation--becomes enlarged. However, upon retirement, the cabbie's hippocampus will likely shrink. Spector's research has far-reaching implications in fields as diverse as oncology and parenting, and it provides a new perspective on the age-old nature-vs.-nurture debate--turns out they may be on the same team. Agent: Sophie Lambert and Kevin Conroy Scott, Tibor Jones & Associates (U.K.). (Aug.)

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