環(huán)球英語 — 48：One Human Genome
Voice 1
Thank you for joining us for today’s Spotlight program! I’m Rebekah Schipper.
Voice 2
And I’m Liz Waid. Spotlight uses a special English method of Broadcasting. It is easier for people to understand, no matter where in the world they live.
Have you ever looked at people and just thought about how different they are? You could never get along with them! You have nothing in common with them!
Voice 1
Well, today on Spotlight we will show you that you are not as different from other people as you might think. In fact, your genes are ninety-nine point nine percent the same as everyone else on the earth! Can you believe it? Keep listening!
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It tells your eyes and skin what colour they will be.
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It tells your fingers how long they will be.
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It decides if you will have your mother’s small nose or your father’s big hands.
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It even tells your body if you will be male or female.
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It is found in every part of your body.
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It tells everything inside and outside your body how to act.
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It is your Deoxyribonucleic acid, or DNA. Some people call DNA the building blocks of life. Everyone has his or her own set of DNA. It influences every part of a person’s body.
Voice 1
And it has millions of different parts to it. But there is something truly surprising about DNA. When scientists really began to look at people’s DNA they discovered that people are not really that different from each other. On the outside of their bodies people look different from one another. But when you get down to it, everyone is made of the same stuff!
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DNA is a very complex subject. Before nineteen fifty-three scientists did not even know what DNA really looked like! They knew that something told a person’s body how to grow. But they did not know how. Scientists have been trying to understand DNA ever since they discovered it.
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When scientists first began to study DNA they could not see very much. The technology they used was not powerful enough. Later, technology improved. Technology could then help the scientists get a better look at DNA.
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In the 1950’s scientists discovered that DNA was a kind of chain. This chain had millions of very small chemical substances linked together. They discovered that these substances formed DNA. But there was too much information in DNA for them to write down and study.
Voice 1
They did know that the chain of DNA is made of four important chemical substances. Scientists gave each of these substances short names. Their short names are A, T, C, and G. The order of these letters, or substances tells a body how to grow and act. It is called a DNA code.
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The order of the code is different in every person. But the code is normally only different in a very small way. Most of the letters of the DNA code are in a similar order in every person! The very small differences in the code are very important for the way a person looks. These small differences are the reason for different hair or eye colours.
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In 1986, a group of American scientists had an idea. They wanted to map human DNA. They wanted to discover the order of the DNA codes.
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The project began in 1990. It was called “The Human Genome Project.” The scientists expected the project to take fifteen years to complete. Scientists in Australia, Brazil, Germany, Japan, Mexico and many other countries also set up their own genome projects. And many other countries helped by providing information and money.
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The scientists did not use one person’s complete set of DNA. Instead, they collected genetic examples from people all over the world. They knew that this would be enough for them to study.
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Scientists used computers to help them map the DNA. The DNA code is a series of letters. The computers wrote out the letters in the DNA code. This is called decoding the DNA. The DNA code contains three thousand million [3,000,000,000] letters. That is a very long code! But the computers were very fast. And every second, they decoded twelve thousand [12,000] letters of the DNA code.
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That sounds like a very fast computer! But the process took thirteen [13] years to complete. That is two years less than the scientists predicted. Scientists called the complete set of DNA code a genome.
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When scientists finally finished mapping the human genome in April 2003, they found many surprising results! The human genome is made up of three thousand million [3,000,000,000] different important pieces. Of these three thousand million pieces, only three million [3,000,000] are different in every person. That means that ninety nine point nine [99.9] percent of people’s genes are exactly the same!
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This very small tenth of one percent of different genes is what makes you you. All the other genes making up your DNA are the same as everyone else all across the world. People from Asia, Africa, America, Europe and everywhere in the world are all made up of the same materials. Their genes are almost exactly the same.
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Usually people only think about the differences they see in other people. It’s true that every person is different. People have different colour skin. They have different colour eyes. Some people have short fingers or long toes. You could expect that every person’s DNA is also very different.
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Sometimes people are afraid of other people who are different than them. People usually like to stay by people they think are similar to themselves. But the Human Genome Project showed that people are more similar to each other than they think.
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Do you remember that person you thought you could never get along with? You may be different on the outside, but inside you are very similar to them.
Voice 1
In the Bible, Jesus asks Christians to love other people. He does not mean that people should only love others who are similar to themselves. Jesus means that people should love others even if they are different. In fact, he says it is one of the greatest things Christians can do. Jesus says:
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“All that God’s law says can be combined into one command: love others as much as you love yourself.”
