chapter 20

• One of the great achievements of modern science has been the sequencing of the human genome, which was largely completed by 2003.
• Progress began with the development of techniques for making recombinant DNA, in which genes from two different sources—and often different species—are combined in vitro into the same molecule.
• The methods for making recombinant DNA are central to genetic engineering, the direct manipulation of genes for practical purposes.
  • Applications include the introduction of a desired gene into the DNA of a host that will produce the desired protein.
• DNA technology has launched a revolution in biotechnology, the manipulation of organisms or their components to make useful products.
  • Practices that go back centuries, such as the use of microbes to make wine and cheese and the selective breeding of livestock, are examples of biotechnology.
    • These techniques exploit naturally occurring mutations and genetic recombination.
• Biotechnology based on the manipulation of DNA in vitro differs from earlier practices by enabling scientists to modify specific genes and move them between organisms as distinct as bacteria, plants, and animals.
• DNA technology is now applied in areas ranging from agriculture to criminal law, but its most important achievements are in basic research.

The DNA profiles that follow represent four different individuals.

51) Which of the following statements is consistent with the results?

A) B is the child of A and C.
B) C is the child of A and B.
C) D is the child of B and C.
D) A is the child of B and C.
E) A is the child of C and D.

Which of the following statements is most likely true?

A) D is the child of A and C.

B) D is the child of A and B.

C) D is the child of B and C.

D) A is the child of C and D.

E) B is the child of A and C.

Which of the following are probably siblings?

A) A and B
B) A and C
C) A and D
D) C and D
E) B and D