World without Cats Read Online Free Page A

murmur from the audience.
    “This is George,” said Noah, cradling the scrawny feline in his arms. “George has a disease called macroerythrocytic feline anemia, MEFA for short.” Gently stroking the gaunt animal, Noah explained the analogy between sickle cell anemia in humans and MEFA. He described how the red blood cells of cats afflicted with this disease would swell up like little balloons because their hemoglobin was defective. “Cats with MEFA are lethargic,” he pointed out. “They lie around all day, panting pathetically, and they rarely live to maturity.” He explained that the disease was the result of a naturally occurring mutation in the gene for one of the hemoglobin proteins called alpha-globin.
    “What we hope to do is to isolate and clone the gene for normal alpha-globin from a healthy cat and then to attach this gene to a viral chromosome. The virus we use is called feline sarcoma virus and sometimes causes tumors in cats.”
    “Why don’t you just say cancer?” yelled an angry male voice from the middle of the auditorium.
    “All right, cancer,” Noah acknowledged. He had to remind himself not to raise his voice. “However, the strain we use has been genetically altered so that it can no longer cause cancer. It is what we call a defective virus.” Noah wiped his brow. “Anyway, after we attach the globin gene to this virus chromosome, we will allow the virus to infect certain immature blood cells from cats with MEFA. We hope that, as these cells mature, they will form normal alpha-globin in these sick animals.”
    Noah paused to let his words sink in and looked over the audience. They were quiet now, obviously interested in his proposed research. He noticed quite a few puzzled faces. “Before I go on, I would be happy to answer any questions.”
    Noah nodded toward a thirtyish, bearded man wearing blue jeans and a loose-fitting white shirt embroidered with birds and flowers.
    “Dr. Chamberlin, my name is Norman Orgell. I teach biology at Camarillo High. I have several questions. First, what kind of bacteria do you use for cloning the alpha-globin gene?”
    “We use a type of Escherichia coli, the common intestinal bacterium.”
    “Isn’t that dangerous? Isn’t there a chance that someone in the lab could ingest the bacteria, which could then multiply in the gut? Couldn’t such a person carry the bacteria, with their recombinant DNA, everywhere he or she went?”
    Noah was prepared for this one. “There are two reasons why there is no danger. First, we use a mutant of E. coli incapable of surviving in the gut of any animal, including humans. Our strain of E. coli has many, many mutations that prevent it from competing with normal bacteria in the intestine. It can only survive in the highly complex artificial media that we prepare for it.
    “Secondly, the recombinant DNA itself is not dangerous. There is no way the gene for alpha-globin could be dangerous to anyone, even if, by some remote chance, it did manage to escape from the lab.”
    “Thank you. I think I understand,” said Norman Orgell.
    Noah spotted a blond woman with her hand raised. She looks familiar, Noah thought. Quite a looker. She’s been taking notes.
    “Dr. Chamberlin, my name is Vera Barnett. I’m a veterinarian. I’m embarrassed to admit it, but I’ve never heard of MEFA. Is it very widespread?”
    “No, not at all,” Noah replied. “As I mentioned, cats inheriting the disease rarely live to sexual maturity, so there is a strong natural selection against MEFA. The disease is what you might call a laboratory curiosity.”
    “Then where do you get cats with MEFA?” asked the veterinarian.
    “The disease was discovered about ten years ago in the laboratory of Thomas Stambaugh at Harvard. Two kittens from a litter of five were scrawnier than the others and, when he examined the blood of these kittens, he noticed the abnormal red blood cells. He reasoned that by analogy with sickle cell anemia in humans, MEFA