Text 3. It's All In Your Genes
What colour hair have you got? Is it straight, wavy or curly? What colour are your eyes? Why are some people tall and slim while others are short and stocky? It's all in your genes. Each person on this planet is unique, because everyone has got a different combination of genes. These are contained in the DNA structure. Your genes determine your general shape and size, the colour of your skin, eyes and hair, the shape of your face, nose, ears, mouth and teeth.
For every part of your body you have got two genes. You inherit one from your mother and one from your father. One of the two genes is dominant, but you can pass either gene on to your children. Look at this couple, for example. The man and the woman both carry a gene for blue eyes and a gene for brown eyes, which they have inherited from their own parents, but they have both got brown eyes, because the brown gene is always dominant.
In this ideal example the couple has two sons and two daughters and each one has received one of the four possible combinations of the parents' genes. As we can see, one of them is blue-eyed and the other three have got brown eyes, but three of them carry a blue gene.
A gene can stay hidden in a family for generations. For example, the second daughter is married. Her husband's eyes are brown, but he also carries a blue gene. This couple has got four children and each child has got a different combination of the parents' genes. So one child has got blue eyes, although her parents and grandparents have all got brown eyes.
Knowledge about genes has been used since the eighteenth century to improve plants and animals. Scientists and farmers select the best possible specimens to breed from. In this way they have been able to produce bigger fruit and vegetables, animals that produce more meat, kinds of wheat or rice that are more resistant to disease, and so on. This is known as selective breeding.
Now scientists can actually identify the genes for particular characteristics. In the new science of genetic engineering, genes can be removed, added or replaced to produce the characteristics that --we want. New and better plants and animals will be produced by genetic engineering. Will we be able to design the perfect human being, too? 'Nobody's perfect', we say. Perhaps one day everyone will be.
Text 4. The Americans and Computers
This new servant of man is only about twenty-five years old, but it has already changed the lives of more that 200 million Americans. Wherever the citizen turns, he finds a computer working. It helps him make long-distance and local telephone calls.
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Computers are also used when one reserves space on an airplane. Walk into airline office. Before selling you a ticket, the reservation clerk uses machine to record information about where you want to go and the flight number of the plane that will take you to your destination. This information is sent instantly to a central computer that may be many kilometres away from the airline office. Within seconds, the computer informs the clerk whether or not there is space for you on that plane.
Such reservation systems are now in increasing use. They are also employed by hotels, by companies that rent cars, and by offices that sell tickets to theatres and sport events. The computer not only determines what seats are available at what prices, but it also prints the tickets at the same time.
When you buy an automobile, a factory process, that is controlled by a computer, enables you to obtain a car with your own choice of colors and special features in just a few weeks' time. In medical laboratories, computers have reduced the errors in testing, and they have saved doctors countless hours of work. Before long, medical histories of all Americans will be kept in "computer banks". If a person becomes ill far from his home, local doctors will be able to get his medical record immediately. In science, the computer has performed in minutes experiments which would have required thousands of hours of work by human hands and minds.
More and more Americans use computers in their daily lives. In some American schools, for example, young children are being taught by computers for part of the school day.
The use of computers in schools has worried some Americans. There are those who fear it will remove the human element from teacher-student relationship. Some teachers fear that computers will take their jobs. On the other hand, there are educators who consider computers a valuable means of freeing teachers from the more boring and tiring tasks, enabling them to spend more time with individual students.
In education, as in business and industry, science and medicine, computers play an important part in almost every type of operation. The future will bring major advances in computer technology and applications, which will aid man in his efforts to improve his world.
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