Darwin''s Radio
If a police officer saw Stella, or somebody reported her, there could be trouble.
Kaye called Mitch at the Chevrolet dealership where he worked, a few miles from their house, and he told her he’d come right home.
The children had never seen anything quite like this odd little girl. Just being around her made them feel friendly and good, and they did not know why, nor did they care. The girls chatted about clothes and singers, and Stella imitated some of the singers, especially Salay Sammi, her favorite. She was an excellent mimic.
The boy stood to one side, frowning in concentration.
The younger girl went next door to invite other friends over, and they in turn invited others, and soon the backyard was filled with boys and girls. They played house, and the boys played police, and Stella provided sound effects and something else, a smile, a presence, that soothed and energized them at once. Some had to go home and Stella said she was glad to meet them and smelled behind their ears, which made them laugh and draw back in embarrassment, but none of them felt angry.
They were all fascinated by the gold and brown dapples on her face.
Stella seemed completely at ease, happy, but she had never been among so many children before. When two nine-year-old girls, identical twins, asked her different questions at once, Stella answered them both, at once. They could almost understand what she said, and they broke out laughing, asking the funny plump little girl where she had learned to do that.
The older boy’s frown changed to determination. He knew what he had to do.
Kaye and Mitch called her name along the street. They did not dare ask the police for help; Arizona had finally gone along with the Emergency Action and was sending its new children for special study and education in Iowa.
Kaye was beside herself. “It was just a minute, just—”
“We’ll find her,” Mitch said, but his face gave him away. He looked incongruous in his dark blue suit, walking on the dusty street between the small old houses. A hot dry wind soaked up their sweat. “I hate this,” he said for the millionth time. It had become a familiar mantra, part of the bitterness inside him. Stella made him feel complete; Kaye could still give him some of the old life. But when he was alone, the strain filled him to the brim, and in his head he would say over and over how much he hated this.
Kaye held his arm and told him again how sorry she was.
“Not your fault,” he said, but he was still very angry.
The thin girl showed Stella how to dance. Stella knew a lot of ballet music; Prokofiev was her favorite composer, and the difficult scores came out in complexes of piping and whistling and clucking. One little blond boy, younger than Stella, stayed as close as he could to her, brown eyes big with interest.
“What do we want to play now?” the tall girl asked when she grew tired of trying to stand en pointe.
“I’ll get Monopoly,” said an eight-year-old boy with the more familiar kind of freckles.
“Or maybe we can play Othemo?” Stella asked.
They had been searching for an hour. Kaye stopped for a moment on a broken patch of sidewalk and listened. The alley that ran behind their homes opened onto this side street, and she thought she heard children playing. Lots of children.
She and Mitch walked quickly between the garages and board fences, trying to catch Stella’s voice, or one of her many sounds.
Mitch heard their daughter first. He pushed open the metal swinging gate and they entered.
The small yard was packed with children like birds around a feeder. Kaye noticed immediately that Stella was not the center of attention; she was simply there, off to one side, playing a game of Othemo, with decks of cards that made sounds when pressed. If the sounds matched or made a tune, the players got to discard. The players who emptied their hands first won. This was one of Stella’s favorites.
Mitch stood behind Kaye. Their daughter did not see them at first. She was chattering happily with the twins and another boy.
“I’ll get her,” Mitch said.
“Wait,” Kaye said. Stella appeared so happy. Kaye was willing to risk a few minutes for this.
Then Stella looked up, pushed to her feet, and let the musical cards fall from her hands. She circled her head in the air and sniffed.
Mitch saw another child, a boy, enter the yard from a gate in the front. He was about Stella’s age. Kaye saw him, too, and recognized him immediately. They heard a woman’s frantic calls in Spanish and Kaye knew what they were, what they meant.
“We have to leave,” Mitch said.
“No,” Kaye said, and held him back with her arm. “Just for a moment. Please. Watch!”
Stella and the boy approached each other. The other children one by one fell silent. Stella circled the young boy, face blank for a long moment. The boy made small sighs, his chest heaving as if he had been running. He rubbed at his face with quick dabs of spit on his sleeve. Then he bent over and sniffed behind Stella’s ear. Stella sniffed behind his ear and they held hands.
“I’m Stella Nova,” Stella said. “Where are you from?”
The small boy just smiled, and his face twitched in ways Stella had not seen before. She found her own face responding. She felt the rush of blood to her skin and she laughed out loud, a delighted, high-pitched shriek. The boy smelled of so much—of his family and the way his home smelled and of the food his mother cooked, and his cats, and Stella watched his face and understood a little of what he was saying. He was so rich, this little boy. Their dapples colored madly, almost at random. She watched the boy’s pupils fleck with color, rubbed her fingers on his hands, feeling the skin, the shivers of response.
The boy spoke in broken English and Spanish simultaneously. His mouth moved in a way that Stella was familiar with, shaping the sounds passing along both sides of his ridged tongue. Stella knew a fair amount of Spanish and tried to answer. The boy jumped up and down with excitement; he understood her! Talking to people was usually so frustrating for Stella, but this was even worse, because suddenly she knew what talking might really be.
Then she looked to one side and saw Kaye and Mitch.
Simultaneously, Kaye saw the woman in the kitchen window, using her phone. The woman did not look at all happy.
“Let’s go,” Mitch said, and Kaye did not disagree.
“Where are we going now?” Stella asked from her safety seat in the back of the Chevy Lumina as Mitch drove south.
“Mexico, maybe,” Kaye said.
“I want to see more like the boy,” Stella said, pouting fiercely.
Kaye closed her eyes and saw the boy’s terrified mother, grabbing him away from Stella, shooting a dirty look at Kaye; loving and hating her own child. No hope for bringing the two together again. And the woman in the window, too afraid to even come outside and talk with her.
“You will,” Kaye said dreamily. “You were very beautiful with the boy.”
“I know,” Stella said. “He was one of me.”
Kaye leaned over the back of the seat and looked at her daughter. Her eyes were dry, she had thought about this for so long, but Mitch rubbed his eyes with the back of his hand.
“Why did we have to leave?” Stella asked.
“It’s cruel to keep her away from them,” Kaye told Mitch.
“What are we going to do, ship her off to Iowa? I love my daughter and I want to be her father and have her in this family. A normal family.”
“I know,” Kaye said distantly. “I know.”
“Are there many like the boy, Kaye?” Stella asked.
“About a hundred thousand,” Kaye said. “We’ve told you that.”
“I would love to talk with them all,” Stella said.
“She probably could, too,” Kaye said with a smile at Mitch.
“The boy told me about his cat,” Stella said. “He has two kittens. And the kids liked me, Kaye, Momma, they really liked me.”
“I know,” Kaye said. “You were beautiful with them, too.” Kaye was so proud and ye
t her heart ached for her daughter.
“Let’s go to Iowa, Mitch,” Stella suggested.
“Not today, Sweet Rabbit,” Mitch said.
The highway ran straight south through the desert.
“No sirens,” Mitch observed flatly.
“Did we make it again, Mitch?” Stella asked.
AFTERWORD
I’ve made a substantial effort in this novel to make the science accurate and the speculations plausible. The ongoing revolution in biology is far from over, however, and it is very likely that many of the speculations here will turn out to be wrong.
As I’ve done my research and spoken to scientists around the world, I’ve come away with an unshakable sense that evolutionary biology is about to undergo a major upheaval—not in the next few decades, but in the next few years.
Even as I finish revisions, articles are appearing in the scientific literature that support a number of speculative details. Fruit flies, it seems, can adapt in only a few generations to gross changes in climate. The implications of this are still controversial. The most recent, in the December–January 1998–99 issue of New Scientist, points up the contributions that human endogenous retroviruses might make to the progress of HIV, the AIDS virus; Eric Towler, of the Science Applications International Corporation, says he “has evidence that HERV-K enzymes may help HIV to evade potent drugs.” This is similar to the mechanism of swapped viral tool kits that frightens Mark Augustine.
The mystery, as it unfolds, will be absolutely fascinating; we truly are on the verge of discovering the secrets of life.
A SHORT BIOLOGICAL PRIMER
Humans are metazoans, that is, we are made up of many cells. In most of our cells there is a nucleus that contains the “blueprint” for the entire individual. This blueprint is stored in DNA (deoxyribonucleic acid); DNA and its complement of helper proteins and organelles make up the molecular computer that contains the memory necessary to construct an individual organism.
Proteins are molecular machines that can perform incredibly complicated functions. They are the engines of life; DNA is the template that guides the manufacture of those engines.
DNA in eucaryotic cells is arranged in two interwoven strands—the “double helix”—and packed tightly into a complex structure called chromatin, which is arranged into chromosomes in each cell nucleus. With a few exceptions, such as red blood cells and specialized immune cells, the DNA in each cell of the human body is complete and identical. Researchers estimate that the human genome—the complete collection of genetic instructions—consists of between sixty thousand and a hundred thousand genes. Genes are heritable traits; a gene has often been defined as a segment of DNA that contains the code for a protein or proteins. This code can be transcribed to make a strand of RNA (ribonucleic acid); ribosomes then use the RNA to translate the original DNA instructions and synthesize proteins. (Some genes perform other functions, such as making the RNA constituents of ribosomes.)
Many scientists believe that RNA was the original coding molecule of life, and that DNA is a later elaboration.
While most cells in the body of an individual carry identical DNA, as the person grows and develops, that DNA is expressed in different ways within each cell. This is how identical embryonic cells become different tissues.
When DNA is transcribed to RNA, many lengths of nucleotides that do not code for proteins, called introns, are snipped out of the RNA segments. The segments that remain are spliced together; they code for proteins and are called exons. On a length of freshly transcribed RNA, these exons can be spliced together in different ways to make different proteins. Thus, a single gene can produce a number of products at different times.
Bacteria are tiny single-celled organisms. Their DNA is not stored in a nucleus but is spread around within the cell. Their genome contains no introns, only exons, making them very sleek and compact little critters. Bacteria can behave like social organisms; different varieties both cooperate and compete with each other to find and use resources in their environment. In the wild, bacteria frequently come together to create biofilm “cities”; you may be familiar with these cities from the slime on spoiled vegetables in your refrigerator. Biofilms can also exist in your intestines, your urinary tract, and on your teeth, where they sometimes cause problems, and specialized ecologies of bacteria protect your skin, your mouth, and other areas of your body. Bacteria are extremely important and though some cause disease, many others are necessary to our existence. Some biologists believe that bacteria lie at the root of all life-forms, and that eucaryotic cells—our own cells, for example—derive from ancient colonies of bacteria. In this sense, we may simply be spaceships for bacteria.
Bacteria swap small circular loops of DNA called plasmids. Plasmids supplement the bacterial genome and allow them to respond quickly to threats such as antibiotics. Plasmids make up a universal library that bacteria of many different types can use to live more efficiently.
Bacteria and nearly all other organisms can be attacked by viruses. Viruses are very small, generally encapsulated bits of DNA or RNA that cannot reproduce by themselves, Instead, they hijack a cell’s reproductive machinery to make new viruses. In bacteria, the viruses are called bacteriophages (“eaters of bacteria”) or just phages. Many phages carry genetic material between bacterial hosts, as do some viruses in animals and plants.
It is possible that viruses originally came from segments of DNA within cells that can move around, both inside and between chromosomes. Viruses are essentially roving segments of genetic material that have learned how to “put on space suits” and leave the cell.
SHORT GLOSSARY OF SCIENTIFIC TERMS
Amino acid: building block for proteins. Most living things use only twenty amino acids.
Antibody: molecule that attaches to an antigen, inactivates it, and attracts other defenses to the intruder.
Antibiotics: a large class of substances manufactured by many different kinds of organisms that can kill bacteria. Antibiotics have no effect on viruses.
Antigen: intruding substance or part of an organism that provokes the creation of antibodies as part of an immune response.
Bacteria: procaryotes, tiny living cells whose genetic material is not enclosed in a nucleus. Bacteria perform much important work in nature and are the base of all food-chains.
Bacteriophage: see phage.
Bacteriocin: one of many substances created by bacteria that can kill other bacteria.
Chromosome: arrangement of tightly packed and coiled DNA. Diploid cells such as body cells in humans have two sets of twenty-three chromosomes; haploid cells such as gametes—sperm or ova—have only a single set of chromosomes.
Cro-Magnon: early variety of modern human, Homo sapiens sapiens, from Cro-Magnon in France. Homo is the genus, sapiens the species, sapiens the subspecies.
DNA: deoxyribonucleic acid, the famous double-helix molecule that codes for the proteins and other elements that help construct the phenotype or body structure of an organism.
ERV or endogenous retrovirus: virus that inserts its genetic material into the DNA of a host. The integrated provirus lies dormant for a time. ERVs may be quite ancient and fragmentary and no longer capable of producing infectious viruses.
Exon: regions of DNA that code for proteins or RNA.
Gamete: a sex cell, such as egg or sperm, capable of joining with an opposite gamete—egg plus sperm—to make a zygote.
Gene: The definition of a gene is changing. A recent text defines a gene as “a segment of DNA or RNA that performs a specific function.” More particularly, a gene can be thought of as a segment of DNA that codes for some molecular product, very often a protein. Besides the nucleotides that code for the protein, the gene also consists of segments that determine how much and what kind of protein is expressed, and when. Genes can produce different combinations of proteins under different stimuli. In a very real sense, a gene is a tiny factory and computer within a much larger factory-computer, the genome.
/> Genome: sum total of genetic material in an individual organism.
Genotype: the genetic character of an organism or distinctive group of organisms.
HERV or human endogenous retrovirus: Within our genetic material are many remnants of past infections by retroviruses. Some researchers estimate that as much as one third of the sum total of our genetic material may consist of old retroviruses. No instance is yet known of these ancient viral genes producing infectious particles (virions) that can move from cell to cell, in lateral or horizontal transmission. Many HERV do produce viruslike particles within the cell, however, and whether these particles serve a function or cause problems is not yet known.
All HERV are part of our genome and are transmitted vertically when we reproduce, from parent to offspring. Infection of gametes by retroviruses is the best explanation so far for the presence of HERV in our genome. (ERV, endogenous retrovirus, are found in many other organisms, as well.)
Homosome: the complete complement of usable genetic material both inside and outside a cell or organism. Bacteria exchange circular loops of DNA called plasmids and may have some genes carried by lysogenic phages; this total pool of genetic material constitutes the bacterial homosome.
Immune response (immunity, immunization): the provoking and marshaling of defensive cells within an organism to ward off and destroy pathogens, disease-causing organisms such as viruses or bacteria. Immune response may also identify nonpathogenic cells as foreign, not part of the normal body complement of tissues; transplanted organs cause an immune response and may be rejected.
Intron: regions of DNA that do not generally code for proteins. In most eucaryotic cells, genes consist of mingled exons and introns. Introns are clipped out of transcribed messenger RNA (mRNA) before it is processed by ribosomes; ribosomes use the code contained in lengths of mRNA to assemble specific proteins out of amino acids. Bacteria lack introns.