Cloning: A Beginner's Guide

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Would you drink milk from a cloned cow?
Should we clone extinct or endangered species?
Are we justified in using stem cells to develop cures?
When will we clone the first human?

Ever since Dolly the sheep was born, questions like these have been part of the public consciousness, and now, cloning is poised to revolutionize medicine, healthcare, and even the food we eat. Regardless of what certain politicians do to slow the progress of scientific research, cloning is here to stay, and the new paperback book, Cloning: A Beginner's Guide (Oxford, England: OneWorld Publications; 2007), by Aaron Levine, offers an excellent overview and a thought-provoking introduction to the development and science of this fast-paced field of research, from its early days right up to the present-day scandals surrounding attempts to clone humans.

The first chapter of the book, "What cloning is and why it matters" (free PDF), is a good introduction to the science of cloning and what it can do for humans. In the second chapter, Levine reviews pivotal experimental advances in genetics research throughout the past century so the reader gains a general insight into the logical and technological progression of the field. This chapter also focuses on the discovery of the structure and function of DNA, clarifying the relationship between DNA, genes and chromosomes, moves on to discuss cell division and the cell life cycle, then examines mammalian embryonic development from fertilization through birth. The historical development of cloning technology and the scientific process that gave us Dolly, the first mammal cloned from an adult animal cell, is covered in the third chapter. Following the story of Dolly, the next chapter explores potential twenty-first century cloning applications for animals; cloning valuable food animals, cherished pets, and particularly the cloning of endangered or extinct animal species. Curiously, despite the author's wide-reaching knowledge of cloning technology and applications, he never mentions the attempts that are being made to clone extinct mammoths and mastodonts -- of all attempts to clone extinct animals, this is the one that I think is the most likely to yield results.

The book then moves on to discuss embryonic stem cells and their promise for human therapeutic cloning. This chapter briefly touches on the benefits, such as reducing or possibly eliminating immune rejection that so plague organ transplants. It also goes into some depth regarding the promise that embryonic stem cell research has for medicine, especially for treating Parkinson's disease. Interestingly, this chapter also chronicles the scientific scandal that involved Woo Suk Hwang in South Korea. Even though I followed the story closely as it unfolded in real life, having the entire saga documented in one place reads rather like a soap opera.

After having provided a good overview of the history and process of cloning research, Levine discusses the nuances of the ethical debate over cloning, the uncertain atmosphere that surrounds cloning research today, and the possible roles that cloning technology could play in humanity's future. Most interesting to me were the questions raised regarding the ethics and implications of cloning for our food supply and its use to potentially create "animal factories", the use of cloning in medical research and its possible misuse for creating a "master race" of perfect genetically engineered humans. Would such cloned humans ultimately be a separate human species?

I thoroughly enjoyed this book. However, I have one complaint -- only one -- and it is so minor that I am somewhat reluctant to even mention it. In chapter five, Levine mentions the tetraploid embryo complementation technique (p. 103) without first describing the process, which would likely confuse most readers. The reason I mention this here is because the book is so well-written and the ideas progress so smoothly and logically that the mention of this unexplained technique was quite jarring. [Author responds; "I dedicated a paragraph to explaining the technique on page 97 in the box titled "How do scientists know cells are really embryonic stem cells." I see how it may be easy to miss this definition as it wasn't in the main body of the text, but this was why I used the admittedly complex term without defining in the discussion on page 103. Just a small point, but I wanted to let you know." GrrlScientist response: woops! #blush#]

This book was originally published as a paperback so it is very affordable and is small and light enough to carry in a handbag or backpack. Its 193 pages are divided into eight illustrated chapters that each end with a list of between two and four books that will provide the interested reader with a deeper understanding of the issues explored in that chapter. Additionally, references for each chapter are listed in the notes at the end of the book, along with a glossary and an index.

In addition to the quality of the writing itself, I am impressed with the total amount of information contained within this small book and with the attention to detail that went into organizing it: in short, this is the one of the best organized, written and edited books I've ever read on any subject. This book is aimed at the general audience, and in fact, Levine's (non-scientist) mother read and reread his manuscript many times, helping the author to crystallize his thoughts. Regardless of which side of the debate you are on, this book will appeal to you on many levels.

I highly recommend this book to everyone: I think it would be especially good as additional reading material for introductory genetics courses, bioethics and biomedical classes. This little book, along with a few of the books it recommends, could be used by a clever teacher or professor as the basic framework around which a complete course could be designed that specifically focuses on cloning research and technology. Further, this book is so interesting and well-written that it would be an excellent stand-alone guide for book clubs and discussion groups.

Aaron Levine is a Ph.D. Candidate in the Science, Technology and Environmental Policy (STEP) cluster of the Ph.D. program in Public Affairs at the Woodrow Wilson School at Princeton University. His dissertation explores stem cell policy and focuses specifically on assessing the impact of the atypical policy environment on the development of human embryonic stem cell research.


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Every apple and potato you have ever eaten was cloned. It is truly astonishing that cloning animals gets such special treatment, when the biggest real difference between producing identical animals and producing identical plants is that it is much easier to produce the plants.

Some of the same issues re. animals (esp. lack of genetic diversity) are true with regard to plants as well. The Irish potato famine was largely caused by the fact that the Irish grew only one variety of potato. Every potato in Ireland was a clone, and they all succumbed to the blight.

You're right, of course, that many plants are cloned, but for a variety of reasons this practice doesn't raise the same level of public concern as cloned animals. Most notable among these reasons is that plant cloning doesn't make people think of human cloning in the same way that animal cloning does. For better or worse, in the decade since scientists learned how to clone mammals from adult cells, almost all discussions of cloning have been shaped by the possibility that the technique will one day be applied to humans for reproductive purposes.

More info about the book is available at

By Aaron Levine (not verified) on 25 Oct 2007 #permalink

by crazy coincidence, I went to a museum exhibit about mammoths just yesterday, and there was some discussion of the efforts to clone them. Here's what I learned:

As you know, frozen mammoth remains have been found, so naturally scientists have examined the DNA (with the idea of potentially cloning them). Unfortunately, freezing the cell breaks the DNA strands (you probably know more of the details on this point than I do), so scientists have not been able to sequence the mammoth's DNA completely yet. They have discovered, however, that mammoths are very closely related to modern elephants (as closely as African elephants and Asian elephants are related to each other). So it has been suggested that if they find a frozen mammoth with intact testicles, then since sperm can be viable after being frozen, they might be able to use the sperm to impregnate a living elephant (producing a hybrid, of course, not a clone).