单选题
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 break-through for family trees where information is incomplete or
missing due to adoption, illegitimacy 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 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 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 case we can look
primarily at the Y chromosome (染色体)," explains George Green, a member of the BYU
Molecular Genealogy research team.
单选题
People in a large area may possess the same DNA thread because______.
A. DNA is characteristic of a region
B. they are beyond doubt of common ancestry
C. DNA strand has the ability to identify individuals
D. their unique identification can be provided via DNA
【正确答案】
B
【答案解析】[解析] 理解题。题干是对第一句中的“there are also regions of the DNA strand”的改写。前面提到“DNA具有遗传性”，既然是遗传，那么可以推断出具有同样DNA特征的人必定有同样的祖先。所以应选B。
单选题
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 is
related to others
D. we can use DNA to prove how distant an individual is to a family, a group
or a population
单选题
The Molecular Genealogy Research Group is building a database for the
purpose of______.
A. offering assistance in working out genealogy-related problems
B. solving many issues without relying on traditional written records
C. providing a pedigree chart of at least four generations in the
world
D. confirming the assumption that all individuals are of the same
origin
【正确答案】
A
【答案解析】[解析] 细节题。根据第二段中的“…help in solving many issues regarding genealogies that could not be done by relying only…”可知，建立数据库有助于解决仅靠其他方法不能解决的与宗谱有关的许多问题。所以应选A。
单选题
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