Restriction Enzymes, Recombinant DNA, Gene Therapy & Genetically

Modified Organisms

Biology 2011

Restriction Enzymes

• What they are:– Enzymes obtained from bacteria that cut DNA

• What they do:– Used to cut DNA at specific regions = restriction

sites– They can produce DNA with “sticky ends”– List of enzymes & restriction sites

http://www.neb.com/nebecomm/products/category1.asp

Restriction Enzymes (cont.)• How we use them:– To cut DNA into pieces for

• gel electrophoresis• PCR• Gene cloning• To insert new DNA into an organism• Gene splicing - cutting DNA and inserting new DNA

Recombinant DNA

• What is it:– DNA from two organisms that is joined together– rDNA

• How it is done:– DNA from both organisms is cut with the same

restriction enzyme to get sticky ends– The pieces of DNA are then joined together using

ligase.– http://www.youtube.com/watch?v=x2jUMG2E-ic

Recombinant DNA (cont.)

Uses of Recombinant DNA

http://www.youtube.com/watch?v=YVdLJ78RBWk

http://www.youtube.com/watch?v=n0UzdYRnMtY&feature=related

Gene Therapy

• What it is:– Technique for correcting defective genes that

cause disease

• How– A new gene could be inserted into the genome

using a “vector” to deliver the DNA– Viruses are often used as vectors

Current Status of Gene Therapy

http://videos.howstuffworks.com/tlc/29327-understanding-gene-therapy-treatment-video.htm

http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml

Genetically Modified Organisms

• What are they?– Organisms whose genetic material has been

altered using genetic engineering techniques– Transgenic organisms – organisms with DNA from

another species

GMO Uses - Insulin Production

• The gene for human insulin has been inserted into bacteria which are able to produce it.

• http://www.youtube.com/watch?v=AEINuCL-5wc&feature=related

GMO Crops• Crops have been developed that are – Resistant to environmental conditions (freezing,

drought)– Resistant to herbicides– Resistant to pests– Higher nutrient content (rice that is higher in iron

and beta carotene

GMO animals• Pharming - Genetically engineered goats

produces milk containing Atryn, a human anticoagulant

• Glow-in-the-dark fish, cats, mice, plants, bacteria

• Knockout mice – mice that have genes that are turned off ; provides a model for studying and modeling different human diseases (cancer, obesity, heart disease, arthritis, Parkinsons disease…)