Alan McHughen - DNA Demystified: Unravelling the Double Helix

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Alan McHughen 2020

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Library of Congress Cataloging-in-Publication Data

Names: McHughen, Alan, author.

Title: DNA demystified : unraveling the double helix / Alan McHughen.

Description: New York : Oxford University Press, [2020] |

Includes bibliographical references and index.

Identifiers: LCCN 2019052495 (print) | LCCN 2019052496 (ebook) |

ISBN 9780190092962 (hardback) | ISBN 9780190092986 (epub) |

ISBN 9780190092993 (online)

Subjects: LCSH: DNA. Classification: LCC QP624 .M39 2020 (print) |

LCC QP624 (ebook) | DDC 572.8/6dc23

LC record available at https://lccn.loc.gov/2019052495

LC ebook record available at https://lccn.loc.gov/2019052496

To Donna

I work with DNA. This is my answer, when asked at a social event, What do you do for a living? Invariably, the reply is some variant of Oh, Wowthats a fascinating topic. I wish I knew more about DNA, but its so complex, and my degree is in History/Geology/ Law... and everything I read is either too technical or too simplistic.

And I, invariably, wished I could hand them a suitable book. This is now that book.

My own fascination with genetics, especially molecular genetics, started fifty years ago, in high school. To be precise, Grade 10 biology class. Most of my classmates, including me, were quickly confused, lost in the apparent enormity of the subject, from the complex helical structure to the varied and intricate functions of DNA. But our teacher, the large and imposing Mr. Hobin, reassured us. Right now, gentlemen, he said to the all-boy class, DNA seems like a whole lot of little bits of unconnected information. But persevere, he continued and youll find those little pieces will start coalescing, fitting together like pieces of a jigsaw puzzle, and ultimately, gentlemen, youll see the big picture.

Being sixteen years old, none of us believed him. But, being obedientor perhaps intimidatedwe persevered anyway. Most of us eventually found he was correct. The big picture DNA is logical, economical, and methodical, with almost everything about DNA fitting together and making sense. Yes, some basic technical terms required rote memorization. But once learned and applied within a few conceptual frameworks DNAs big picture came clear.

Many people share my fascination with DNA, albeit usually not enough to make molecular genetics a career objective. And some people dont share my enthusiasm for using our knowledge of DNAvia technologyto improve the human condition. After all, they might say, human history is littered with attempts to improve on nature that ended up making a mess. I reply there are, indeed, risks associated with all technologies. I endorse learning from past mistakes, then moving cautiously and judiciously forward, cognizant that not developing technology also carries risk. Today, as a molecular geneticist and public educator, I encounter many people who are fascinated by but equally fearful of DNA and what it means, particularly when we humans manipulate, modify, or engineer it. I appreciate that there is considerable apprehension among the public, but much anxiety is based on fearful misconceptions that can be allayed by fairly simple, factual, uncontroversial knowledge.

This book explains what DNA is and how it adheres to ordinary laws of science and nature. This book is for the interested nonspecialist who wants to better understand how DNA works as the genetic material for all living things.

We start with an introduction to DNA. What it is and how it does the amazing things it does. The initial chapters span the range of awesome feats accomplished by DNA, along with what DNA is physically, chemically, and biologically. We also cover some historical background to some of the salient discoveries of DNA and its features. No doubt some critics will bemoan my omitting brilliant men and women who made important discoveries, and I accept this criticism. More complete histories are available elsewhere, and here I try to provide just the essential historical details to allow a better appreciation of the subsequent technical developments.

DNA is not unique to Homo sapiens, but a chapter devoted to genetic features of our own species is in order because we humans are so self-centered and self-absorbed, and because so much DNA research is conducted for the benefit of humans.

With the foundation laid in the first several chapters, we move to the second part of the book, focused on applications of DNA information. These chapters illustrate how DNA is used to address issues in various and diverse fields, from the sublime (e.g., human origins) to the ridiculously mundane (e.g., Whose dog pooped on my lawn?). We move then into personal DNA and genetics, exploring the recent explosion of interest in DTC (direct-to-consumer) DNA testing. What are the opportunities? And what are the limitations of such tests? provides some guidance in choosing a suitable test and company to conduct that test, based on your specific interests and motivations.

The final section of the book delves into rewriting the DNA recipes. We cover the promiseor perhaps the specterof genetic engineering, GMO crops and foods, and genome editing to produce custom babies. This leads into some uncomfortable ethical issues deriving from DNA knowledge and technology. We wrap up with a nontechnical discussion of the role of human understanding of genetics and modification of DNA. In 1998, Britains Prince Charles, Prince of Wales, feared our newfound knowledge of DNA and modification... takes mankind into realms that belong to God and to God alone (https://www.princeofwales.gov.uk/speech/article-prince-wales-titled-seeds-disaster-daily-telegraph). Twenty years later, we can revisit his angst to discuss whether his concerns were well founded. Should we use DNA technologies to combat intractable diseases, famines, and climate change? Should we modern humans, instead, eschew knowledge and technology, returning to an entirely natural biological niche? Or is there a middle ground, where we might judiciously apply at least some DNA technologies to serve a safer, healthier, more sustainable future?

For those seeking more, the notes appended to each chapter provide sources and, where available, links to primary citations and technical papers, as well as links to news reports, blogs, and websites offering more accessible resources and explanations for the topic for further reading. All links were tested as active in early 2020, but be aware that web page content is ephemeral and can change or even disappear without warning.