50 genetics ideas you really need to know
Mark Henderson
New York • London © 2009 by Mark Henderson All rights reserved. No part of this book may be reproduced in any form or by any electronic or mechanical means, including information storage and retrieval systems, without permission in writing from the publisher, except by reviewers, who may quote brief passages in a review. Scanning, uploading, and electronic distribution of this book or the facilitation of the same without the permission of the publisher is prohibited. Please purchase only authorized electronic editions, and do not participate in or encourage electronic piracy of copyrighted materials. Your support of the author’s rights is appreciated. Any member of educational institutions wishing to photocopy part or all of the work for classroom use or anthology should send inquiries to Permissions c/o Quercus Publishing Inc., 31 West 57th Street, 6th Floor, New York, NY 10019, or to
[email protected] ISBN 978-1-62365-184-8 Distributed in the United States and Canada by Random House Publisher Services c/o Random House, 1745 Broadway New York, NY 10019 www.quercus.com
Contents Introduction CLASSICAL GENETICS 01 The theory of evolution 02 The laws of inheritance 03 Genes and chromosomes 04 The genetics of evolution 05 Mutation 06 Sex MOLECULAR BIOLOGY 07 Genes, proteins and DNA 08 The double helix 09 Cracking the code of life 10 Genetic engineering THE GENOME 11 Reading the genome 12 The human genome 13 Lessons of the genome NATURE AND NURTURE 14 Genetic determinism 15 Selfish genes 16 The blank slate 17 Nature via nurture GENES AND DISEASE 18 Genetic diseases 19 Gene hunting 20 Cancer 21 Superbugs SEX, HISTORY AND BEHAVIOR 22 Behavioral genetics
23 Intelligence 24 Race 25 Genetic history 26 Genetic genealogy 27 Sex genes 28 The end of men? 29 The battle of the sexes 30 Homosexuality GENETIC TECHNOLOGIES 31 Genetic fingerprinting 32 GM crops 33 GM animals 34 Evo-devo 35 Stem cells 36 Cloning 37 Cloning people 38 Gene therapy 39 Genetic testing 40 Tailor-made medicines 41 Designer babies 42 Brave new worlds 43 Genes and insurance THE NEW GENETICS 44 Gene patenting 45 Junk DNA 46 Copy number variation 47 Epigenetics 48 The RNA revolution 49 Artificial life 50 No such thing as normal Glossary
Introduction We are living through a revolution in human understanding. For as long as our species has been capable of complex thought, people have wondered where we come from, why we behave as we do, how our bodies work in sickness and in health, and why we all seem so similar and yet display such diverse and wonderful individuality. Philosophy and psychology, biology, medicine and anthropology, even religion, have all attempted to supply answers, and not without some success. But until very recently, we have been missing a fundamental piece of the puzzle, with significance for every aspect of human existence. A knowledge of our genetic code. Genetics is a young science. It is little more than 50 years since Crick and Watson discovered the structure of the DNA molecule in which organisms’ cellular instructions are written. The first, incomplete, draft of the human genome was published only in 2001. Yet this infant branch of knowledge is already changing the way we understand life on Earth, and genetic technology is transforming the way we live. Genetics has shed fresh light on our history, proving the fact of evolution, and allowing us to trace how the first humans emerged from Africa to populate the world. It has brought us new forensic tools that can convict the guilty and exonerate the innocent. And it is explaining how our