2. 外语
  3. We all know that DNA has the ability to identify individuals but, because it is inherited, there are also regions of the DNA str

We all know that DNA has the ability to identify individuals but, because it is inherited, there are also regions of the DNA str

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问题     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(私生)or lack of records. There are many communities and populations which have lost precious records due to tragic events such as the fire in the Irish corms 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(家谱) 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 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 this ease we can look primarily at the Y chromosome (染色体))," explains Ugo A. Perego, a member of the BYU Molecular Genealogy research team.
Which of the following CAN NOT be inferred from the passage?
选项 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 identity.
D、Molecular Genealogy can be used to prove a relationship between individuals.
答案C
解析 可以推断出A“我们的方方面面记录着我们的祖先”正确，因为DNA具有遗传特性；B“许多美国黑奴不知道他们的祖先”，正确，依据是第一段最后一句；C“收养的孩子或者孤儿与他们的家族树没有关系”，不正确，因为他们与家族树的关系是基因特征而不是其他因素决定的；D“宗谱学能用来证明人与人之间的关系”，识别和证明人的身份关系是宗谱学的目的，正确。
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大学英语四级

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