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Genetic modification (基因改良) dates back to ancient times, when humans influenced genetics by selectiv

英语试题 08-11
Genetic modification (基因改良) dates back to ancient times, when humans influenced genetics by selectively breeding organisms (培育生物) according to an article by Gabriel Rangel, a public health scientist at Harvard University. When repeated over several generations, this process leads to great changes in the organisms.
Dogs were likely the first animals to be purposefully genetically modified, with the beginnings of that effort dating back about 32,000 years, according to Rangel. Wild wolves joined our hunter-gatherer ancestors in East Asia, where the aggressive canines were kept in the household and bred to become docile and easier to get along with. Over thousands of years, people bred dogs with different desired character and physical characteristics, eventually leading to the wide variety of dogs we see today.
The earliest known genetically modified plant is wheat. This valuable crop is thought to have originated in the Middle East and northern Africa in the area known as the Fertile Crescent, according to a 2015 article published in the Journal of Traditional and Complementary Medicine. Ancient farmers selectively bred wheat grasses beginning around 9000 B. C. to create improved varieties with larger grains and hardier seeds. By 800 B.C., the cultivation (培养) of improved wheat had spread across Europe and Asia. The continued selective cultivation of wheat resulted in the thousands of varieties that are grown today.
Corn has also experienced some of greatest genetic changes over the past few thousand years. The main crop was changed from a plant known as teosinte, a wild grass with tiny ears and only a few seeds. Over time, farmers selectively bred the teosinte grasses to create corn with large ears bursting with seeds.
Beyond those crops, many of the fruit and vegetables we eat today, including bananas, apples and tomatoes, have experienced several generations of selective raising, according to Rangel.
In 1973, researchers also modified bacteria to be used as drugs. In 1982, human insulin (胰岛素) made from genetically engineered bacteria, became the first genetically engineered human drugs approved by the FDA.
12. What does the word “docile” in paragraph 2 most probably mean?
A. Gentle. B. Loyal. C. Smart. D. Ambitious.
13. How did the ancient farmers try to improve wheat?
A. Through selective cultivation. B. By editing its genes constantly.
C Through mixture with teosinte. D. By planting it in large numbers.
14. What can we infer about genetic modification?
A. It is rarely seen in daily life. B. It was quite difficult to accept.
C. It is hardly influenced by humans. D. It played a role in medical field.
15. From which section of a newspaper is the text most probably taken?
A. Health. B. Lifestyle. C. Science. D. Agriculture.
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