Virolution
The extraordinary role of viruses in evolution and how this is revolutionising biology and medicine.Darwin's theory of evolution is still the greatest breakthrough in biological science. His explanation of the role of natural selection in driving the evolution of life on earth depended on steady variation of living things over time – but he was unable to explain how this variation occurred. In the 150 years since publication of the Origin of Species, we have discovered three main sources for this variation – mutation, hybridisation and epigenetics. Then on Sunday, 12th February, 2001 the evidence for perhaps the most extraordinary cause of variation was simultaneously released by two organisations – the code for the entire human genome. Not only was the human genome unbelievably simple (it is only ten times more complicated than a bacteria), but embedded in the code were large fragments that were derived from viruses – fragments that were vital to evolution of all organisms and the evidence for a fourth and vital source of variation – viruses.Virolution is the product of Dr Frank Ryan's decade of research at the frontiers of this new science – now called viral symbiosis – and the amazing revolution that it has had in these few years. As scientists begin to look for evidence of viral involvement in more and more processes, they have discovered that they are vital in nearly every case. And with this understanding comes the possibility of manipulating the role of the viruses to help fight a huge range of diseases.
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FRANK RYAN
Virolution
The most important evolutionary book since Dawkins’ Selfish Gene
William Collins An imprint of HarperCollinsPublishers 1 London Bridge Street London SE1 9GF
First published by Collins 2009
Text & diagrams © FPR-Books Ltd 2009
Frank Ryan asserts his moral right to be identified
as the author of this work.
A catalogue record for this book is available from the British Library.
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Source ISBN: 9780007315123
Ebook Edition © JULY 2013 ISBN: 9780007545278
Version: 2018–12–04
To the memory of Terry Yates, for the courtesyand generosity of his help and the inspirationthat gave rise to this life-changing journey.
Science knows no country because it is the light that illuminates the world.
LOUIS PASTEUR
Like science, emerging viruses know no country. There are no barriers to prevent their migration across international boundaries or around the 24 time zones.
RICHARD M KRAUSE
A relatively small number of investigators have been preoccupied with the biology of viruses … and how they tick; these scientists are more sensitive to the … evolution of their symbiotic relations with their hosts.
JOSHUA LEDERBERG>1
Contents
Introduction: A Wind of Change
1: An Enigma from the World of Plagues
5: The Paradox of the Human Genome
6: How Viruses Helped Make Us Human
7: The Implications for Medicine
11: Sex in the Evolutionary Tree
I am quite sure that our views on evolution would be very different had biologists studied genetics and natural selection before and not after most of them were convinced evolution had occurred.
JBS HALDANE>1
In the opening line of his celebrated book, The Ascent of Man, Jacob Bronowski declared that ‘man is a singular creature. He has a set of gifts which make him unique among the animals.’ Putting aside the now outmoded sexual conventions implicit in his terminology, our natural instinct is to believe he was right. Surely we humans are unique. We are unique in recognising, at sentient level, our own existence. We have risen above the other animals in the landscape so that, for good or for bad, we now shape and control that landscape. But does this intellectual uniqueness mean that we are so radically different that we should be set apart from all other life in our evolutionary origins, which have governed the very nature of our beings?
When, on 12 February 2001, two rival organisations announced simultaneously that they had completed the first comprehensive analysis of the human genome, surely this would have confirmed any such purported uniqueness of our human nature. Here, laid bare, for the first time in our history, was the complete library of our genes, the make-up of the 46 chromosomes that make us human. Alas, of any purported uniqueness it registered little. Nevertheless, it was remarkable for what it did reveal.
The first surprise was the modest size of the human genome, at about 20,000 genes. We had anticipated that our human complexity would have demanded 100,000, or more. To put it into perspective, we have only ten times as many genes as a bacterium, a third more than a fruit fly and not many more than a nematode worm. It seems that, at least in quantity of genomic memory, we are not vastly more complex than these humble life forms, though our genome is far more complex in the way we convert genes to proteins, so we can code for a great many more proteins with the same number of genes. Most revealing of all was the confirmation of our common inheritance with other forms of life on Earth. For example, we share 2,758 of our genes with the fruit fly, 2,031 with the nematode worm – indeed, all three of us, human, fly, and worm, have 1,523 genes in common.
While some of my readers might feel humbled by this news, I suspect that Darwin would have been exhilarated because he would have realised that this shared inheritance could not have arisen by chance. We are familiar with the extreme accuracy of genetics in forensic science where a small piece of genetic coding can prove that a certain individual, and nobody else, committed a crime. To have 1,523 whole genes in common is rather more conclusive evidence – I could not even begin to calculate the order of the odds of this happening by chance, whether billions or trillions to one. And this touches upon the reasons why evolutionary biology is among the most fascinating and important of the sciences, and indeed generally of human endeavours: it alone seeks, through the application of logic and experiment, to understand the origins of life, from its beginnings in such humble and terrible surroundings as existed on our newborn planet, to the beautiful and beguiling diversity we see on our fecund blue world today.
