15.1 Selective Breeding

Humans use selective breeding, which takes advantage of naturally occurring genetic variation, to pass wanted traits on to the next generation of organisms.

Breeders can increase the genetic variation in a population by introducing mutations, which are the ultimate source of biological diversity.

• selective breeding (418)

• inbreeding (419)

• hybridization (419)

• biotechnology (419)

15.2 Recombinant DNA

The first step in using the polymerase chain reaction method to copy a gene is to heat a piece of DNA, which separates its two strands. Then, as the DNA cools, primers bind to the single strands. Next, DNA polymerase starts copying the region between the primers. These copies can serve as templates to make still more copies.

Recombinant-DNA technology—joining together DNA from two or more sources—makes it possible to change the genetic composition of living organisms.

Transgenic organisms can be produced by the insertion of recombinant DNA into the genome of a host organism.

• polymerase chain reaction (423)

• recombinant DNA (424)

• plasmid (424)

• genetic marker (425)

• transgenic (426)

• clone (427)

15.3 Applications of Genetic Engineering

Ideally, genetic modification could lead to better, less expensive, and more nutritious food as well as less-harmful manufacturing processes.

Recombinant-DNA technology is advancing the prevention and treatment of disease.

DNA fingerprinting analyzes sections of DNA that vary widely from one individual to another.

• gene therapy (431)

• DNA fingerprinting (433)

• DNA microarray (432)

• forensics (433)

15.4 Ethics and Impacts of Biotechnology

Should you, like patent holders, be able to keep your genetic information confidential?

Careful studies of GM foods have provided no scientific support for concerns about their safety.

There are many concerns about unintended consequences that a shift to GM farming and ranching may have on agriculture.

Just because we have the technology to modify an organism's characteristics, are we justified in doing so?

Think Visually Complete the following concept map.

dd