(1) Some 200,000 babies are born in the United States each year with deformed bodies, impaired minds and possibly fatal abnormalities in body chemistry – often because of defective genes or chromosomes. If a way could be found to “test” routinely the genes of prospective married couples – much as the couples now take Wassermann tests to detect syphilis – the toll might be reduced drastically. This is the goal of genetic counseling. And while it is still far off – testing is expensive and elaborate – genetic counseling centers in hospitals and clinics across the United States are already helping parents. At a symposium sponsored by the National Foundation March of Dimes in New York City, it was announced that between 1955 and 1969 the number of centers had grown from 20 to 114. such centers help the parents of a defective child in their decision whether or not to have more children, and they advise couples with family histories of genetic diseases even before marriage.
(2) The genes that help determine a person’s individual characteristics – from the color of his eyes to the score he makes on an IQ test – are located on chromosomes within the cells of his body. Half of a person’s chromosomes come from his father, half from his mother. Many diseases are the result of a single defective gene on one of the chromosomes. Achondroplastic dwarfism, for example, is caused by a dominant gene and any child who inherits it will have the disease. A genetic counselor confronted by a parent with such a disease could warn that half of his children risk the disease.
(3) More often, genetic diseases are caused by recessive genes. The most common is cystic fibrosis, a disorder that affects at least on in every 1,600 babies and causes their lungs and other body organs to become congested with mucus. A child who inherits only one of these recessive genes will not have the disease, but will be a carrier. If both parents are carriers, one in four of their children will have cystic fibrosis, two will be carriers, and one will be normal.
(4) Some diseases, such as the bloodclotting disorder, hemophilia, are sex-linked recessive defects carried on the female X chromosome. These genes generally produce disease only in male children when the X chromosome bearing the faulty gene pairs with the father’s Y chromosome. Half the sons of a female hemophilia carrier risk the disease; half the daughters may be carriers.
(5) Many genetic defects, such as the hemophilia of European royalty, can be traced back through the family tree. And a genetic counselor can calculate probable risks for couples even before they have defective children. But faulty genes may also occur without warming by mutation in any generation. Dr. Kurt Hirschhorn of New York City’s Mount Sinai School of Medicine noted that everyone carries from three to eight deleterious recessive genes which will not make their presence known unless they combine with similarly defective genes at conception and the child is born with a defect.
(6) In recent years, researchers have detected a number of disorders caused by an extra chromosome, or lack of part of a chromosome. Mongolism, a form of retardation accompanied by short stature, a flattened nose and broad hands and feet, is caused by an extra chromosome. The parents of such a child have little increased risk of having another Mongloid, but in a few cases, the Mongolism can be passed on from generation to generation by carriers. One in three of the carrier’s children is Mongoloid, one is a carrier and one is normal.
(7) Until recently, much of genetic counseling has relied on estimates based on the law of averages. But researchers have begun to develop lab tests fro carriers. There are blood, urine and other tests which show promise in detecting more than 100 genetic diseases, including cystic fibrosis, phenylketonuria (PKU), hemophilia and some forms of muscular dystrophy. As a result, a genetic counselor can tell the sister of a man with hemophilia with reasonable certainty whether she is a carrier.
(8) Researchers are also detecting genetic defects even before a child is born. By amniocentesis, a process in which a needle is inserted through the mother’s abdomen and into her uterus, researchers can withdraw samples of the fluid surrounding the fetus. By growing these fetal cells in tissue culture, researchers can detect chromosome defects or chemical abnormalities. “Intra-uterine detection,” notes Dr. Henry L. Nadler of Northwestern University Medical School, “brings a new dimension to genetic counseling. The physician may now inform the parents that they will have either an affected or a normal child.”
(9) One of Nadler’s patients was a 39-year-old pregnant woman who was found to carry the extra chromosome that causes Mongolism. As a result of the diagnosis, the woman had a therapeutic time, his studies showed that she would give birth to a Norman child. He was right.
chromosomes: (生物)染色体
syphilis: (医)梅毒
toll: 代价
cystic: （医）膀胱的，胆囊的
fibrosis: (生)纤维症，纤维化
mucus: 粘液
bloodclotting: 血块，血凝结
hemophilia: 血友病
mutation: （生物物种的）突变
deleterious: 有害的，有毒的
Mongolism: 蒙古症
retardation: 延迟，阻滞
Mongoloid: （医）先头愚型患者
phenylketonuria: （医）苯丙酮酸尿症（先天代谢异常）
dystrophy: 营养失调
amniocentesis: （医）羊水诊断
uterus: （解）子宫
fetus: 胎儿
therapeutic: 治疗的，疗法的

I. There are 10 incomplete statements, followed by four choices marked A, B, C and D. Choose the best answer.
1. Paragraph 1 tells the main idea that ______.
A. all physical and mental abnormalities are caused by defective genes
B. Genetic counseling could decrease the number of people born with genetic defects
C. Many babies are born with diseases
D. Genetic counseling is expensive and not available in most hospitals in the U.S.
2. “Achondroplastic dwarfism, for example, is caused by a dominant gene an any child who inherits it will have the disease.” This is used as an example to support which of the following statements.
A. “Many diseases are the result of a single defective gene on one of the chromosomes.”
B. “The genes that help determine a person’s individual characteristics – from the color of his eyes to the score he makes on an IQ test – are located on chromosomes within the cells of his body.”
C. “Half of a person’s chromosomes come from his father, half from his mother.”
D. “A genetic counselor confronted by a parent with such a disease could warn that half of his children risk the disease.
3. According to Paragraph 3,
A. any child who inherits the recessive genes will be diseased.
B. recessive genes are dangerous because they cause all the lung problems.
C. a child will become a carrier if both of his parents are carriers.
D. a child who inherits only one of these recessive genes will be a carrier.
4. The best classification for the information in Paragraph 4 is ______.
A. hemophilia: bloodclotting disorder
B. hemophilia: female X chromosome
C. sex-linked recessive defects: hemophilia
D. hemophilia: male Y chromosome
5. The main idea of Paragraph 5 is ______.
A. “Many genetic defects… can be traced back through the family tree.”
B. “But faulty genes may also occur without warning by mutation in any generation.”
C. “A genetic counselor can calculate probable risks for couples even before they have defective children.”
D. All of the above.
6. It is evident from the context in Paragraph 6 that “Mongoloid” refers to ______.
A. a retarded person
B. an Oriental
C. a person from Mongolia
D. extra chromosome
7. The best classification of the information in Paragraph 7 is ______.
A. success of genetic counseling
B. hemophilia risks for carriers
C. genetic counseling for carriers
D. lab tests fro carriers
8. What is the relationship between Paragraph 9 and 8?
A. They are not connected.
B. Paragraph 9 is a counter-example disagreeing with the two previous statements in Paragraph 8.
C. Paragraph 9 is an example supporting the two previous statements in Paragraph 8.
D. Paragraph 9 is a summary of the article.
9. We can infer from the article that ______.
A. experts in this field are mostly reliable
B. experts in this field are not at all reliable
C. genes are inherited, they can’t be changed or controlled
D. faulty recessive genes are in to be found in every human body
10. The subject of this article is ______.
A. genetic determination of individual characteristics
B. sex-linked recessive defects
C. new developments in genetic analysis and counseling
D. diseases inherited from genes

II. There is one underlined part in each of the following sentences, followed by four choices A, B, C and D. Choose the one that is the closest in meaning to the underlined part.
1. A genetic counselor confronted by a parent with such a disease could warn that half of his children risk the disease.
A. challenged by
B. encountered with
C. accused by
D. blamed by
2. Some diseases, such as the bloodclotting disorder, hemophilia, are Sex-linked recessive defects carried on the female X chromosome.
A. hidden faulty genes in the female sex
B. the female X chromosome likely to be infected
C. the faulty genes carried by both sexes.
D. the faulty genes hidden in the female X chromosome which produce disease only in male children when the X chromosome bearing the faulty gene pairs with the father’s Y chromosome.
3. Everyone carries from three to eight deleterious recessive genes which will not make their presence known unless they combine with similarly defective genes at conception and the child is born with a defect.
A. make people aware of their existence
B. present themselves
C. arouse people’s concern
D. be detected through equipments
4. Intra-uterine brings a new dimension to genetic counseling.
A. size
B. measurement
C. expanse
D. perspective
5. As a result of the diagnosis, the woman had a therapeutic abortion.
A. an unexpected lose of her child
B. a medical operation to remove a fetus from a woman’s uterus
C. a successful operation to save her child
D. an unsuccessful operation and died

III. Translate the following sentences into Chinese.
1. The genes that help determine a person’s individual characteristics – from the color of his eyes to the score he makes on an IQ test – are located on chromosomes within the cells of his body.
2. A child who inherits only one of these recessive genes will not have the disease, but will be a carrier.
3. But faulty genes may also occur without warning by mutation in any generation.
4. In recent years, researchers have detected a number of disorders caused by an extra chromosome, or lack of part of a chromosome.
5. By amniocentesis, a process in which a needle is inserted through the mother’s abdomen and into her uterus, researchers can withdraw samples of the fluid surrounding the fetus.

IV. Answer the following essay question in English with 80-100 words.
Is there any inherited genetic defect that you know besides the ones mentioned in this article?

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