Recombinant DNA Use for Recombinant DNA Examples of Environmental Mutagens The Ch 26 Objectives

Define Recombinant DNA (rDNA) is produced when DNA from more than one source is isolated and recombined. These processes utilize the techniques developed through biotechnology. To produce rDNA, a segment of DNA must be isolated and then introduced into a vector (usually bacterial DNA (plasmids) which replicate on their own). This insertion of the isolated DNA segment into a plasmid is accomplished using restriction enzymes and a DNA ligase enzyme

Describe 3 Uses for Recombinant DNA Use 1: Cloning of Genes Cloning of genes involves making copies of genes in a laboratory. These genes can be used to determine the difference between a normal and mutated gene or produce a transgenic organism (having genes from more than one species) for commercial or research purposes. DNA cloned in large quantities using Polymerase Chain Reaction (PCR) can be used for analysis and DNA fingerprinting. DNA fingerprinting identifies similarities in DNA and can indicate evolutionary relationships, paternal or maternal identity, or someone's presence at a crime scene.

Use 2: Biotechnology Products Recombinant DNA technologies can alter the cells of bacteria, plants, and animals to produce biotechnology products or perform specific functions. Transgenic bacteria have been developed to produce insulin, growth hormone, vaccines, artificial sweeteners, and plant toxins. Bacteria can be engineered to eat oil and clean up spills on beaches, biofilter airborne pollutants, and extract precious metals in mining operations.

Transgenic plants have foreign genes inserted to make them resistant to pests and tolerant to herbicides. Big business sells these seeds commercially along with large volumes of their herbicide. Plants can also be engineered to produce human hormones, proteins, and antibodies.

Transgenic animals are produced when foreign genes are inserted into animal eggs. The resulting offspring are transgenic organisms. If the inserted gene is for growth hormone from a cow you end up with really big rabbits. It is also possible to produce cloned transgenic farm animals that produce proteins or hormones with pharmaceutical benefits in their milk. These cloned transgenic organisms (eg. laboratory mice) are also being used extensively in research studies as their identical genetic make up provides a control. In the future, it is possible that human organs will be produced for transplantation purposes through biotechnology.

Use 3: Gene Therapy Gene therapy uses the insertion of human genes directly into cells to replace missing or defective ones. Cells can be altered by the insertion of the gene outside the body (ex vivo) or inside the body (in vivo). Treatments have been developed using gene therapy for diseases like severe combined immunodeficiency (SCID) and Cystic Fibrosis (CF).

Give examples of two environmental mutagens that can cause mutations in humans. Mutagens are environmental agents that may cause mutations in DNA. The term mutation describes any change in the genetic code (DNA) within a cell. Mutations in the DNA of body cells, called somatic mutations, may lead to cancer. Mutations in the DNA of sperm or egg, called germinal mutations, may lead to genetic disorders in the offspring.

High energy radiation from radioactive elements, X- rays, gamma rays, microwaves, and ultraviolet light (use sunscreen and wear a hat). -Industrial chemicals such as PCB's (support the ban). -Pollutants such as smoking ( don't smoke ). -Pesticides (eat organic). -Food Additives (read food labels). -Drugs (use only when necessary). -Viruses (wash your hands).