The Ch 26 Objectives
Recombinant DNA
Use for Recombinant DNA
Examples of Environmental Mutagens
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, Xrays, 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).