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Rediscovering Biology: Molecular to Global Perspectives

Genetically Modified Organisms

While genetic modification of organisms has occurred naturally since life began, we now have the tools to insert specific genes from one organism into cells of unrelated species. This unit illustrates the processes used, and how such genetically transformed organisms are increasingly common in agriculture, industry, and medicine, and introduces the ethical considerations of GMO research.

The online textbook chapters support and extend the content of each video. The Web version can be viewed as a full chapter or as individual sub-sections, and includes links to glossary terms and other related material.

Explore the archive of animations, images and figures from the videos and online textbook. All of the images can be viewed online or downloaded as jpg files.

Read profiles of the expert scientists featured in the video and find the complete transcripts of the interviews conducted for this unit.

Leon Corzine
David L. Dornbos, Jr, PhD
Rebecca J. Goldburg, PhD
Marion Nestle, PhD, MPH
Thomas E. Newberry
Gary H. Toenniessen, PhD

Chapter Contents

Genetic Modification of Bacteria
Getting the Plasmid In
Are Recombinant Bacteria Safe?
Genetic Modification of Plants
Techniques Used for Generating Transgenic Plants
Problems and Concerns
Genetic Modification of Animals
Cloning Animals
Addressing the Controversies

Unit Glossary

The bacterium Bacillus thuringiensis; also refers to the crystalline insecticidal protein produced by the bacterium. Bt crops, such as Bt-corn, are transgenic plants that express the insecticidal protein.

Two or more genetically identical progeny. Clones can be of genes, cells, or whole organisms.

Cloning vector
A carrier of DNA that can replicate; usually a plasmid, bacteriophage, or eukaryotic virus.

Use of electric shock to make cell membranes temporarily more permeable to molecules such as DNA.

Gene gun
A device which delivers DNA to cells by microprojectile bombardment.

Marker gene
A gene, such as one that encodes antibiotic resistance, that allows genetically modified cells to be readily selected.

mRNA splicing
In eukaryotic cells, the process of excising introns from a primary RNA transcript and joining together exons to form a final mRNA molecule.

Recombinant DNA
DNA that contains information from two or more different species of organisms.

Restriction enzymes
Enzymes that cut DNA at specific sequences; also known as restriction endonucleases.

Southern blot
A technique for transferring DNA fragments separated by electrophoresis to a filter paper sheet. The fragments are then probed with a labeled, complementary nucleic acid to help determine their positions.
Transgenic organism
An organism that contains hereditary information from two different species of organisms.
Cells that can replicate to form any part of a complete organism.
Reverse transcriptase
An enzyme that makes a DNA copy using an RNA template.

Unit Animations

  • Creation of a Transgenic Animal
    The steps involved using nuclear transfer to create a transgenic goat that produces a human protein in its milk.
    View Quicktime Movie
  • Creation of Golden Rice
    A diagrammatic representation of the enzymatic pathway constructed to produce beta carotene in the endosperm of a rice plant.
    View Animation Still
  • Recombinant DNA
    The steps involved in genetically modifying a plant.
    View Quicktime Movie

Related Resources

Crotty, S. 2001. Ahead of the curve: David Baltimore’s life in science. Berkeley, CA: University of California Press.
A biography of one of the major figures in molecular genetics and recombinant DNA technology.

Nelson, G. C., ed. 2001. Genetically modified organisms in agriculture – economics and politics. New York: Academic Press.
This book presents opinions regarding the use of genetically modified crops and uses citations from the scientific literature as a foundation for those opinions.

Food and Agriculture Organization of the United Nations (FAO). 2001. Evaluation of allergenicity of benetically modified foods, Report of a Joint FAO/ WHO Expert Consultation on Allergenicity of Food Derived from Biotechnology 22-25 Jan 2001. Rome, Italy.
A report and recommendations from a group of experts who met under the auspices of the United Nations.

Lowell Statement on Science and the Precautionary Principle. 2001.Statement from the international summit on science and the precautionary principle. Hosted by the Lowell Center for Sustainable Production, University of Massachusetts, Lowell; 20-22 September 2001.
The precautionary principle developed by this group is provided in full at this Web site.

Moffat, A. S. 1998. Toting up the early harvest of transgenic plants. Science282:2176-78.
A brief review of recent advances in transgenic agriculture.

Wolfenbarger, L. L., and P. R. Phifer. 2000. The ecological risks and benefits of genetically engineered plants. Science 292:637-38.
A review of the ecological considerations inherent to the development of genetically engineered crops.

Ye, X., A. A. Babili, A. Kloti, J. Zhang, P. Lucca, P. Beyer, and I. Potrykus. 2000. Engineering the provitamin A beta-carotene biosynthetic pathway into (carotenoid-free) rice endosperm. Science 287:303-5.
The scientific paper that presents the development of “golden rice.”

Series Directory

Rediscovering Biology: Molecular to Global Perspectives


Produced by Oregon Public Broadcasting. 2003.
  • Closed Captioning
  • ISBN: 1-57680-733-9