We all know that DNA has the ability to identify individuals, but because it is inherited, there are also regions of the DNA strand which can relate an individual to his or her family(immediate and extended);tribal group and even an entire population. Molecular Genealogy(宗谱学)can use this unique identification provided by the genetic markers to link people together into family trees。Pedigrees（家谱）based on such genetic markers can mean a breakthrough for family trees where information is incomplete or missing due to adoption，illegitimacy（违法）or lack of record. There are many communities and populations which have lost precious records due to tragic events such as the fire in the Irish courts during Civil war in 1921 or American slaves for whom many records were never kept in the first place.

   The main objective of the Molecular Genealogy Research Group is to build a database containing over 100,000 DNA samples from individuals all over the world. These individuals will have provided a pedigree chart of at least four generations and a small blood sample. Once the database has enough samples to represent the world genetic make-up, it will eventually help in solving many issues，regarding genealogies that could not be done by relying only on traditional written records. Theoretically, any individual will someday be able to trace his or her family origins through this database.

   In the meantime, as the database is being created, molecular genealogy can already

Verify（鉴定）possible or suspected relationships between individuals。“For example，if two men sharing the same last name believe that they are related，but no written record proves this relationship，we can verify this possibility by collecting a sample of DNA from both and looking for common markers（in these case we can look primarily at the Y chromosome（染色体），”explain Ugo A. Perego, a member of the BYU Molecular Genealogy research team.

1) The possible research of family trees is based on the fact that _____________.

  A) genetics has achieved a breakthrough

  B) genetic information contained in DNA can be revealed now

  C) each individual carries a unique record of who he is and how he or related to others

  D) we can use DNA to prove how distant an individual is to a family, a group or a population

2) If two men suspected for some reason they have a common ancestor,__________.

  A) we can decide according to their family tree

  B) we can find the truth from their genetic markers

  C) we can compare the differences in their Y chromosome

  D) we can look for written records to prove their relationship

3) Which of the following CAN NOT be inferred from the passage?

  A) we are a walking, living, breathing record of our ancestors

  B) Many American slaves did not know who their ancestors were

  C) An adopted child generally lacks enough information to prove his identify

  D) Molecular genealogy can be used to prove a relationship between individual

We each have a unique genetic (基因的，遗传的) make-up. Every cell of your body has the same set of about 100,000 separate genes made of DNA. These are the instructions for producing a person. Genes decide everything from the colour of your skin to the way your brain works. You have one of several billion combinations of DNA which come from the random mixing of your parents’ genes. Except for identical twins (同卵双胞胎), no one has the same combination as another person. You are unique! You are unique in another way too: in the way you are raised and all the experiences you have from before birth to adult life. These experiences influence you, your behaviour and attitudes, and the choices you make.
But are genes or life experiences more important in shaping your appearance and personality? Scientists are studying twins to find out. One set of twins occurs every 70 births---some are identical and others are non-identical twins. Identical twins are special because they share exactly the same genes and often the same environment. Non-identical twins are more like ordinary brothers and sisters.
Some identical twins have been adopted and brought up in different homes. With identical genes but a different home environment, scientists can study twins to see how much a particular feature depends on the genes we inherit. For example, we know that eye problems, like short-sightedness, are mostly genetic. But resistance to pain is largely dependent on experiences. Genes also influence our eating habits. Identical twins brought up apart often like to eat at the same time of day and feel full after eating the same amount. Non-identical twins in similar circumstances have more varied eating habits. Identical twins are also more likely to follow the same patterns for marriage and divorce than non-identical twins.
Scientists are trying to identify the different genes that influence our behaviour. Some people are thrill-seekers and get into risk-taking and adventurous activities. They take up extreme sports like bungee jumping and possibly take drugs. Scientists have discovered a gene which affects this.
We could ask, “Are our lives determined by our genes or our upbringing?” Scientists are learning more all the time, but it is certainly true that both are important in making us who we are.
【小题1】What is the main idea of the first paragraph?

We each have a unique genetic (基因的，遗传的) make-up. Every cell of your body has the same set of about 100,000 separate genes made of DNA. These are the instructions for producing a person. Genes decide everything from the colour of your skin to the way your brain works. You have one of several billion combinations of DNA which come from the random mixing of your parents’ genes. Except for identical twins (同卵双胞胎), no one has the same combination as another person. You are unique! You are unique in another way too: in the way you are raised and all the experiences you have from before birth to adult life. These experiences influence you, your behaviour and attitudes, and the choices you make.

But are genes or life experiences more important in shaping your appearance and personality? Scientists are studying twins to find out. One set of twins occurs every 70 births---some are identical and others are non-identical twins. Identical twins are special because they share exactly the same genes and often the same environment. Non-identical twins are more like ordinary brothers and sisters.

Some identical twins have been adopted and brought up in different homes. With identical genes but a different home environment, scientists can study twins to see how much a particular feature depends on the genes we inherit. For example, we know that eye problems, like short-sightedness, are mostly genetic. But resistance to pain is largely dependent on experiences. Genes also influence our eating habits. Identical twins brought up apart often like to eat at the same time of day and feel full after eating the same amount. Non-identical twins in similar circumstances have more varied eating habits. Identical twins are also more likely to follow the same patterns for marriage and divorce than non-identical twins.

Scientists are trying to identify the different genes that influence our behaviour. Some people are thrill-seekers and get into risk-taking and adventurous activities. They take up extreme sports like bungee jumping and possibly take drugs. Scientists have discovered a gene which affects this.

We could ask, “Are our lives determined by our genes or our upbringing?” Scientists are learning more all the time, but it is certainly true that both are important in making us who we are.

1.What is the main idea of the first paragraph?

   A. We cannot easily change our physical appearance.

   B. How we turn out depends on our parents’ genes.

   C. Everyone has a physical double somewhere in the world.

   D. Both our genes and our experiences make us who we are.

2.Why are scientists studying twins?

   A. To find out how many twins are born every year.

   B. To discover what shapes us as individuals.

   C. To compare differences between twins.

   D. To study brother-and-sister relationships.

3.According to the passage, __________.

   A. one in 70 twins are genetically identical

   B. non-identical twins are usually not of the same sex

   C. twins separated at birth behave exactly the same

   D. identical twins are genetically the same

4.Which of the following is most affected by experience according the passage?

   A. Eating habits.   B. Eye-sight.   C. Pain resistance.   D. Marriage patterns.

5.What does the underlined “this” in Paragraph 4 refer to?

   A. Our love of sport.             B. Our attitude to risk-taking.

   C. Our skill at bungee jumping.    D. Our ability to take drugs.

We each have a unique genetic (基因的，遗传的) make-up. Every cell of your body has the same set of about 100,000 separate genes made of DNA. These are the instructions for producing a person. Genes decide everything from the colour of your skin to the way your brain works. You have one of several billion combinations of DNA which come from the random mixing of your parents’ genes. Except for identical twins (同卵双胞胎), no one has the same combination as another person. You are unique! You are unique in another way too: in the way you are raised and all the experiences you have from before birth to adult life. These experiences influence you, your behaviour and attitudes, and the choices you make.
But are genes or life experiences more important in shaping your appearance and personality? Scientists are studying twins to find out. One set of twins occurs every 70 births---some are identical and others are non-identical twins. Identical twins are special because they share exactly the same genes and often the same environment. Non-identical twins are more like ordinary brothers and sisters.
Some identical twins have been adopted and brought up in different homes. With identical genes but a different home environment, scientists can study twins to see how much a particular feature depends on the genes we inherit. For example, we know that eye problems, like short-sightedness, are mostly genetic. But resistance to pain is largely dependent on experiences. Genes also influence our eating habits. Identical twins brought up apart often like to eat at the same time of day and feel full after eating the same amount. Non-identical twins in similar circumstances have more varied eating habits. Identical twins are also more likely to follow the same patterns for marriage and divorce than non-identical twins.
Scientists are trying to identify the different genes that influence our behaviour. Some people are thrill-seekers and get into risk-taking and adventurous activities. They take up extreme sports like bungee jumping and possibly take drugs. Scientists have discovered a gene which affects this.
We could ask, “Are our lives determined by our genes or our upbringing?” Scientists are learning more all the time, but it is certainly true that both are important in making us who we are.

1. 1.

   What is the main idea of the first paragraph?

   1. A.
      We cannot easily change our physical appearance.
   2. B.
      How we turn out depends on our parents’ genes.
   3. C.
      Everyone has a physical double somewhere in the world.
   4. D.
      Both our genes and our experiences make us who we are.
2. 2.

   Why are scientists studying twins?

   1. A.
      To find out how many twins are born every year.
   2. B.
      To discover what shapes us as individuals.
   3. C.
      To compare differences between twins.
   4. D.
      To study brother-and-sister relationships.
3. 3.

   According to the passage, __________.

   1. A.
      one in 70 twins are genetically identical
   2. B.
      non-identical twins are usually not of the same sex
   3. C.
      twins separated at birth behave exactly the same
   4. D.
      identical twins are genetically the same
4. 4.

   Which of the following is most affected by experience according the passage?

   1. A.
      Eating habits.
   2. B.
      Eye-sight.
   3. C.
      Pain resistance.
   4. D.
      Marriage patterns.
5. 5.

   What does the underlined “this” in Paragraph 4 refer to?

   1. A.
      Our love of sport.
   2. B.
      Our attitude to risk-taking.
   3. C.
      Our skill at bungee jumping.
   4. D.
      Our ability to take drugs.