Personalized genetic diagnosis and therapy say you’ re young and healthy, and you go in for a routine physical. Your doctor take

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问题     Personalized genetic diagnosis and therapy say you’ re young and healthy, and you go in for a routine physical. Your doctor takes a blood sample and has it shipped to a lab. There, a medical technologist places your serum sample on a glass chip the size of a postage stamp. That gene chip might contain up to 50,000 microscopic spots—each with one of the genes in the human genome. When the doctor calls you with the results, he’ 11 tell you which of thousands of human diseases you ’ re at risk for. If you have a defective gene that’ s placing you at risk for disease, he might treat you with a healthy version of the gene to make up for it, keeping you out of harm’ s way.
    Soon, such diagnoses and treatments could be routine, says Mark Kay, MD, a professor of genetics at Stanford University School of Medicine and president of the American Society of Gene Therapy. "In five years, you may be able to go to referral centers and get gene therapy," he says. Although gene therapists have talked like that for a while, and the field has tremendous promise, so far they have demonstrably cured humans of just one disease; severe combined immunodeficiency(SCID). Known as the bubble-boy disease, it decimates the immune system and causes children to die young from infections. While the treatment looks promising, the virus used to deliver the gene in one trial may have activated a gene that causes cancer.
    Such safety issues have dogged gene therapy. But gene therapists are pressing on. More than a dozen advanced clinical trials are underway that use genes to treat a variety of cancers, and other trials are ongoing for multiple sclerosis, AIDS and cystic fibrosis. Dr. Losordo has also begun a large trial of a gene therapy that seems to help patients regrow blood vessels that supply the heart— "grow your own bypass, if you will," he says. "It’ s a very exciting time. "
    The best gene therapies just treat symptoms. The cells and tissues that make up our body still age, decay and die. "We know of no intervention that will slow, stop or reverse the aging process in humans," says Leonard Hayflick, PhD, professor of anatomy at the University of California, San Francisco, School of Medicine.
    Also, lifesaving technologies and treatments don’ t come cheap, and sometimes terrible side effects emerge. "We will face some very difficult choices," says Thomas Murray, PhD, president of the Hastings Center in Garrison, New York, a think tank that explores ethical issues in biotechnology and health care. Fair enough. But perhaps it’ s OK, for now, to step back and marvel at just how far we’ ve come.
The underlined "decimates" in para. 2 means______.

选项 A、destroys
B、reproaches
C、staggers
D、overwhelms

答案A

解析 decimate意思是“大批杀害”,在文中意思是bubble—boy这种疾病能够摧毁人类免疫系统,使儿童因为感染而死亡。
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