Questions 1-11 are based on the following
passage.
The Human Genome Project was an international scientific research project with the primary goal of mapping all of the genes that make up human DNA. Funded by the U.S. government, it began in 1990 and was successfully completed in 2003. Passage 1 is from the National Human Genome Research Institute website. Passage 2 is from Evolution and Medicine. ©2011 by BSCS.
Passage 1
The Human Genome Project has revealed that there are
probably about 20,500 human genes. The completed human
sequence can now identify their locations. This ultimate
Line product of the Human Genome Project has given the world a
5 resource of detailed information about the structure,
organization and function of the complete set of human
genes. This information can be thought of as the basic set of
inheritable "instructions" for the development and function
of a human being.
10 The International Human Genome Sequencing
Consortium published the first draft of the human genome in
the journal Nature in February 2001 with the sequence of the
entire genome's three billion base pairs some 90 percent
complete. A startling finding of this first draft was that the
15 number of human genes appeared to be significantly fewer
than previous estimates, which ranged from 50,000 genes to
as many as 140,000. The full sequence was completed and
published in April 2003.
Upon publication of the majority of the genome in
20 February 2001, Francis Collins, the director of the National
Human Genome Research Institute, noted that the genome
could be thought of in terms of a book with multiple uses:
"It's a history book - a narrative of the journey of our species
through time. It's a shop manual, with an incredibly detailed
25 blueprint for building every human cell. And it's a
transformative textbook of medicine, with insights that will
give healthcare providers immense new powers to treat,
prevent and cure disease."
Passage 2
Humans vary across the world. Every independently
30 conceived individual is genetically unique. This seems
paradoxical in light of the fact that all humans have a high
degree of genetic similarity. It is often reported that two
humans are 99.9 percent similar in their DNA. However, the
human genome is immense, providing multiple opportunities
35 for genetic variation to arise; the 0.1 percent by which we
differ amounts to 3.3 million nucleotides. Findings from the
International HapMap Project confirm previous studies and
show a relatively low amount of differentiation among
human groups defined by ethnicity and geography. There is
40 much more genetic variation within (about 90 percent) than
among (about 10 percent) human groups. This means that
the similarities among different groups of humans far outweigh
the differences.
As the ability to decipher the genotypes of individuals
45 improves and becomes more widely available, medical
practitioners will be better able to give patients specific
information about their health. Individual genetic profiles
provide useful information about disease susceptibility and
predispositions. Crews and Gerber (2008) suggest three
50 possible medical-clinical applications of individual genetic
profiling: improved screening, more-informed counseling,
and individualized drug formularies. Until more
individualized data are available, however, researchers
continue to try to determine whether disease susceptibility is
55 linked to specific genetic factors and, if so, whether the
genetic factors are distributed differentially among
geographic groups. Patterns of variation among humans have
been shaped by migration, genetic drift, mutation, and
natural selection. These evolutionary mechanisms lead to a
60 correlation between geographic distribution that may be
medically relevant.