Lysogenic phage: phage that attaches to a bacterial capsule and inserts genetic material into the bacterial host, where it then forms a circular loop, integrates with the host DNA, and lies dormant for a time. During this stage, the host bacterium reproduces the prophage or integrated phage genome with its own. Damage or “stress” to a host bacterium may result in the transcription of the phage genes, which then replicate new phages, releasing them by lysing or breaking open the host. In this stage, they are called lytic phage. Lysogenic/lytic phages may also transcribe and carry host genes, along with their own, from one bacterium to another.
Many bacteria that cause severe disease in humans, such as cholera, can have their toxicity triggered by the transfer of genetic material by lysogenic phages. Such phages, understandably, are dangerous in their natural form and useless in controlling bacterial pathogens.
Marker: distinctive or unique arrangement of bases or a distinctive or unique gene within a chromosome.
Modern human: Homo sapiens sapiens. Genus Homo, species sapiens, subspecies sapiens.
Movable element (mobile element): movable segment of DNA. Transposons can move or have their DNA copied from place to place in a length of DNA using DNA polymerase. Retrotransposons contain their own reverse transcriptase, which gives them some autonomy within the genome. Movable elements have been shown by Barbara McClintock and others to generate variety in plants; but some believe these are, more often than not, so-called “selfish genes,” which are duplicated without being useful to the organism. Others believe that movable elements in the DNA contribute to novelty in all genomes, and perhaps even help regulate evolution.
Mutation: alteration in a gene or segment of DNA. May be accidental and unproductive or even dangerous; may also be useful, leading to the production of a more efficient protein. Mutations may lead to variation in phenotype, or the physical structure of an organism. Random mutations are usually either neutral or bad for the health of the organism.
Neandertal: Homo sapiens neandertalensis. Possibly ancestral to humans. Modern anthropologists and geneticists are currently engaged in a debate about whether Neandertals are our ancestors, based on evidence of mitochondrial DNA extracted from ancient bones. More than likely, the evidence is confusing because we simply do not yet know how species and subspecies separate and develop.
Pathogen: disease-causing organism. There are many different varieties of pathogen: viruses, bacteria, fungi, protists (formerly known as protozoa), and metazoans such as nematodes.
Phage: virus that uses bacteria as hosts. Many kinds of phages kill their hosts almost immediately and can be used as antibacterial agents. Many bacteria have at least one and often many phages specific to them. Phages and bacteria are always in a contest to outrun each other, evolutionarily speaking. (See Lysogenic phage.)
Phenotype: the physical structure of an organism or distinctive group of organisms. Genotype expressed and developed within an environment determines phenotype.
Protein: Genes often code for proteins, which help form and regulate all organisms. Proteins are molecular machines made up of chains of twenty different types of amino acids. Proteins can themselves chain or clump together. Collagen, enzymes, many hormones, keratin, and antibodies are just a few of the different types of proteins.
Provirus: the genetic code of a virus while it is contained within the DNA of a host.
Retrotransposon, retroposon, retrogene: see movable elements.
Retrovirus: RNA-based virus that inserts its code into a host’s DNA for later replication. Replication can often be delayed for years. AIDS and other diseases are caused by retroviruses.
RNA: Ribonucleic acid. Intermediate complementary copy of DNA; messenger RNA or mRNA is used by ribosomes as templates to construct proteins.
SHEVA (HERV-DL3, SHERVA-DL3): fictitious human endogenous retrovirus that can form an infectious virus particle, or virion; an infectious HERV. No such HERV is yet known.
Sequencing: determining the sequence of molecules in a polymer such as a protein or nucleic acid; in genetics, discovering the sequence of bases in a gene or a length of DNA or RNA, or in the genome as a whole. In a few years, we will understand the sequence of the entire human genome.
Sex chromosomes: in humans, the X and Y chromosomes. Two X chromosomes results in a female; an X and a Y results in a male. Other species have different types of sex chromosomes.
Transposon: see movable elements.
Trisomy, trisomal: having an extra copy of a chromosome in a diploid cell. In humans, having three copies of chromosome 21 leads to Down syndrome.
Vaccine: a substance that produces an immune response to a disease-causing organism.
Virion: infectious virus particle.
Virus: nonliving but organically active particle capable of entering a cell and commandeering the cell’s reproductive capacity to produce more virus. Viruses consist of DNA or RNA, usually surrounded by a protein coat, or capsid. This capsid may in turn be surrounded by an envelope. There are hundreds of thousands of known viruses, and potentially millions not yet described.
Zygote: the combination of two gametes; a fertilized ovum.
ACKNOWLEDGMENTS
Special thanks to Mark E. Minie, Ph.D., for introducing me to the Puget Sound Biotech Society and many of its members. One of my first contacts was Dr. Elizabeth Kutter of the faculty of the Biology Department of Evergreen State College in Olympia, Washington. She helped me with details about her specialty, bacteriophages, as well as with many facts about one of her favorite places on Earth, the Republic of Georgia. Her assistants, Mark Alan Mueller and Elizabeth Thomas, were constructively critical and encouraging. Our discussions have been both formative and informative!
Mark E. Minie also introduced me to Dr. Dennis Schwartz, whose work on the early chemistry of life may prove revolutionary.
Many other scientists and friends have read and critiqued this book, and a few have given me tours of their facilities. Dr. Dominic Esposito of the National Institutes of Health shepherded me around the NIH campus and made copious notes on an early draft. His friends, Dr. Melanie Simpson and Martin Kevorkian, also provided substantial help.
Benoit Leblanc, Ph.D., working with Dr. David Clark at NIH, in the Laboratory of Cellular and Developmental Biology, did an excellent critical reading, and straightened out many errors in the text.
Brian W. J. Mahy, Ph.D., Sc.D., Director of the Division of Viral and Rickettsial Diseases at the Centers for Disease Control and Prevention, was kind enough to meet with me and share some of his insights into viruses and their possible contributions to evolution. He also critiqued a later draft of the book. Barbara Reynolds of the Public Information Office of the CDC helped arrange a tour of the facilities at 1600 Clifton Road.
Dr. Joe Miller, of Texas Tech University Health Sciences Center, read the book in its earliest draft and provided details about the chemistry of human hormones and vomeronasal receptors.
Julian Davies, Professor Emeritus of the University of British Columbia, kindly agreed to look over the final draft.
Katie and Charlie Potter provided sage advice on mountain climbing, its history and terms.
Even with the help of all these excellent readers, errors certainly remain. They belong to me, not them. Also, at every step of the way, these scientists have expressed both support and doubts about my theories, sometimes severe doubts. Their aid in no way implies that they agree with any or all of the theories in Darwin’s Radio.
A CONVERSATION WITH
GREG BEAR
Q: In much of your fiction, you’ve explored the cultural, biological, psychological, and evolutionary implications of nanotechnology, artificial intelligence, and related biotech fields. Is there a kind of mutation going on now as a result of social and technological change similar to what you describe in Darwin’s Radio? What will it mean to be human fifty or one hundred years from now?
A: Nanotechnology and biotechnology point toward a time, not too far off, when we
can have complete control of our bodies and even of the way we think. These choices lead to some fascinating possibilities, including designer bodies and designer minds, and the rather disturbing notion of fashion adopting the biosciences. I think we may have to understand who we actually are right now to understand what we could be, given fifty or a hundred years of this development. In other words, we have to redefine what it means to be human, because some of our offspring will really be pushing the envelope.
Q: The title of the book, Darwin’s Radio, is very interesting. Where did it come from?
A: I’m always on the lookout for a good title. This one emerged as a description of the core element in the story—viruses in our genome that function as carriers of evolutionary tidings—genetic radio. I’ve always been interested in the notion of viruses as transports for genetic information, and this seemed a poetic description of such a process.
Q: William Burroughs believed language was a virus. But language can incorporate many different means of organizing and propagating information through space and time: in bytes, for example, or in DNA. Are viruses carriers of information or is information itself a kind of virus?
A: All living things communicate in a variety of codes, all of which I loosely collect under the term “language.” Information does not start out as language or code—but our senses quickly convert what we perceive into code to be processed and incorporated, or rejected as memory. If incorporated, it becomes part of our chemistry and it affects how we behave afterwards. We can then exchange this “digested” information with others who share our spoken or written language; and it then becomes cultural knowledge. Bacteria go through a similar process with what they learn: how many bacteria there are in a given place; what kind of resources are available to them; how to avoid or neutralize antibiotics. These useful bits of knowledge are passed on through diffused chemicals or loops of DNA called plasmids, which are like genetic recipes.
DNA is one of the deepest and most fundamental codes we know, yet we have just begun to understand the language of genetics.
Q: The notion that modern humans evolved quite rapidly from Neanderthals is central to your book. Ever since reading Darwin’s Radio, I’ve been amazed by the steady stream of discoveries announced by paleoanthropologists, biologists, and archeologists on the genetic and geographic closeness of Neanderthals and Homo sapiens.
A: There’s considerable uncertainty as to how, even if, humans evolved from Neanderthals, and how long it might have taken. Some theorize that the change happened in one place, and populations radiated outward; others, that it happened in many places. I tend to think that the change happened in many places, at many different times, with many varieties produced in different regions. All (possibly including Neanderthals and modern humans) were likely able to interbreed, and this makes for an incredibly complicated picture, with many subtleties. As we discover more about genetics, some questions will be answered, but many others may well remain lost in history.
Q: What about the mechanism of that evolutionary process or change, the fossilized retroviruses that Kaye Lang discovers in human DNA? Do these pieces of so-called “junk” DNA actually exist as you describe them? How much of what Kaye discovers in the human genome is fact? How much is fiction?
A: HERV (human endogenous retroviruses) exist, and are much discussed in the literature. None of these fossil viruses are able to pass from one individual to another; they aren’t contagious, so far as we’ve been able to discover. But some do produce inactive particles inside cells, perhaps feebly reminiscing over past glories! The only speculation in Kaye Lang’s initial discovery is that she has found bits of HERV able to assemble to create an infectious retrovirus. I then draw on an analogy with lysogenic phages (viruses that infect bacteria), which sometimes do have a role in altering bacterial capabilities by ferrying snippets of DNA. These phages are at once both diseases and helpers, a complex relationship which could have its analogs in humans.
Q: How so?
A: Some viruses, when they insert themselves into DNA and then express and create new viruses, pick up trailing ends of host DNA and carry them to a new host. This genetic swapping could be very powerful, but we’re just beginning to explore the implications. If HERV can express and carry genetic signals, then a situation like that in Darwin’s Radio could very well be possible.
Q: Your work is often described as “hard” science fiction. What does that term mean to you? Do you agree with the assessment?
A: Gregory Benford described hard SF as playing tennis with the net up, and I agree. Doing so captures a vividness and authenticity that resonate with the readers who genuinely do want to experience the world in all its peril and glory. Writing about science is an artistic game with some flexibility; I can describe things that do not yet exist, or play with theories regarded by some as impossible. I just have to show how we can get from where we are now to where my story is, without magic, using science.
Q: Darwin’s Children (Del Rey, April 2003) is quite a different book from Darwin’s Radio. How would you describe their relationship?
A: Darwin’s Radio is about the hardships of getting born—from both the parents’ and the children’s perspectives. I don’t think there’s anything in Darwin’s Radio that is other than a thematic dramatization (and exaggeration, maybe) of what any parent goes through having a child. It’s a tough old world out there, and the fears we experience, contemplating our children’s future, are pretty universal. When a species decides to have a new kind of offspring, to reshape itself in response to a changing environment, is it possible to even begin to imagine the process, the risks involved?
Darwin’s Children is about childhood and adolescence, and then young adulthood. Because of the fear felt by the old for the new, the New Children—some call them Virus Children, a pejorative—have a particularly difficult time growing up.
But there’s an almost equally difficult time in parenting when you have to let your children fend for themselves . . . face the slings and arrows of an unfair society and a difficult world. Children grow away from their parents, and the parents must both protect, nurture, educate . . . and let go. That’s the hardest time of all, and that’s what Darwin’s Children is about on a worldwide as well as a personal scale.
Q: How have scientists reacted to Darwin’s Radio, and how do you think they’ll react to Darwin’s Children?
A: I’ve had tremendous support from a great many working biologists. Not only have they enthusiastically read and corrected my manuscripts, but they’ve engaged in correspondence and personal debate on nearly all the scientific and even political issues involved. That said, a fair number have voiced concern that the severely revised Darwinism of these two books could “aid and comfort” their opponents in the Creationist camp, or even the newly emerging dissenters who seek signs of “intelligent design.” I’m not worried so much about aiding and comforting—or fitting into any particular scientific camp—because my main concern is finding facts and theories that explain what we see in nature, not what academics or religious people think we should be seeing.
The bottom line is, the theories explored in my novels should provide no comfort to those who support Creationism. I’m describing a biological system that runs with little or no outside interference, that is intelligent in its own right, and self-designing in a literal way. This approach is controversial and unlikely to win friends in any of the extreme camps. It’s not even a middle ground—it’s just what I see, and what a fair number of other scientists have seen over the decades. And day by day, in journals published all over the world, the evidence is growing that something like what I describe in Darwin’s Radio is actually happening.
Self-design in species through interactions of population-wide genetic components with environmental stimuli is a scientifically testable hypothesis, and if someone proves it wrong with solid empirical evidence, I’ll move on.
Q: But there’s something else going on in Darwin’s Children that could
raise some eyebrows. You have a main character experiencing a true religious epiphany. How do you think scientists will react to that?
A: It happens. People undergo just this sort of epiphany—some estimates run as high as half of the human race has experienced something very like what my character faces. And it’s a worldwide phenomenon, spread across all religions and, so far as we know, all of history. The experiences seem to be remarkably similar.
To ignore this phenomenon is dishonest. In fact, every day we experience emotional and mental states that cannot be checked out or quantified (so far) in any scientific way. The limits of science—and the limits of faith—are actually quite clear to me, and I believe I make those limits explicit in Darwin’s Children.
I also challenge those who seem to believe that God interferes constantly in our everyday lives, and micromanages the natural world, as well.
Q: And the answer is . . . ?
A: I hope my readers will read these novels carefully and decide for themselves. Knee-jerk reactionaries of any persuasion need not reply. This is a matter of tremendous interest and importance, and defending dogma of any sort just doesn’t interest me. I’m interested in telling stories and seeing what there is to see in the world around us. It’s tremendous fun—and sometimes its very scary.
What more could a writer ask for?
ABOUT THE AUTHOR
GREG BEAR is the author of twenty-five books, which have been translated into seventeen languages. He has been awarded two Hugos and five Nebulas for his fiction. He is married to Astrid Anderson Bear. They are the parents of two children, Erik and Alexandra.
Also by Greg Bear
Psychlone
Blood Music
Songs of Earth and Power