Biology Chapter 20 DNA Technology and Genetic Engineering

The technical application of biological knowledge for human purposes

Applied science that explores applications of cutting, splicing, and creating DNA

Manipulation of the genetic makeup of cells or whole organisms

they enable initiation of DNA synthesis

• Adenine
• Guanine
• Cytosine 
• Thymine

Replicates the DNA

It separates DNA strands by size

cutting, splicing, and copying DNA

1. Restriction enzymes- they cut the DNA at specific sites

2. DNA ligases- join fragments of DNA

3. Plasmids- Small circular pieces of DNA to which desired genes can be added and inserted into bacteria for amplification

They cut DNA at specific sites

Join fragments of DNA

Small circular pieces of DNA to which desired genes can be added and inserted into bacteria for amplification

Can be used to rapidly amplify DNA sequences to obtain millions of copies

1. DNA is amplified, primers, heat-stable DNA polymerase are combined

2. Repeated heating and cooling cycles allow for rapid amplification of a sequence of DNA defined by the primers

1. Often DNA sample must be amplified by PCR first

2. DNA is cut with restriction enzymes

3. Different individuals will have different lengths of DNA between the restriction sites

4. DNA is separated by gel electrophoresis and fragment pattern is compared

1. Insulin

2. Human growth hormone

3. Erythropoiettin

4. Tissue plasminogen activator (TPA)

5. Factor VIII (blood clotting factor needed by many hemophiliacs)

6. Vaccines

1. Increased resistance to freezing

2. Longer shelf life

3. Increased vitamin A

4. Edible vaccines

5. Human proteins

6. Increased resistance to pests

1. "Frankenfoods"

2. Plant disease susceptibility could lead to crop failure

1. More difficult to introduce foreign DNA into animal cells

2. Cloning more difficult

1. Bovine growth hormone (BGH)- used to promote faster animal growth

2. "Gene pharming"- introducing human genes into dairy animals in such a way that the human protein is produced in the animal's milk

Introduction of human genes into human cells to treat or correct a disease

1. Difficult to introduce genes into the "right" cells where the genes would normally be expressed

2. Need effective means of delivering genes

3. Can corrective genes be introduced into reproductive cells to stop the passing of defective genes to offspring

Human genes can be packaged in retroviruses, which can introduce genes into human cells

1. Retroviruses

2. Liposomes

3. Injecting naked DNA

Some success with gene therapy

1. Introduce gene for interleukins to stimulate the immune system

2. Introduce gene for mda 7- a protein that initiates apoptosis