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DNA Technology. Chapter 13. DNA Technology. Genetic Engineering Uses: Cure Diseases Treat Genetic Disorders Improve Food Crops Improve Human Lives. Restriction Enzymes (R.E.). Bacterial enzymes that cut DNA into pieces R.E. recognizes specific nucleotide sequences. “Sticky ENDs”.
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DNA Technology Chapter 13
DNA Technology • Genetic Engineering Uses: • Cure Diseases • Treat Genetic Disorders • Improve Food Crops • Improve Human Lives
Restriction Enzymes (R.E.) • Bacterial enzymes that cut DNA into pieces • R.E. recognizes specific nucleotide sequences
“Sticky ENDs” • Single chain “tails” of DNA that are created on each DNA segment • Sticky Ends readily bond to complementary chains of DNA
Cloning Vectors • Restriction Enzymes can isolate specific gene • Can be transferred by a cloning vector to an organism PLASMID • Small ring of DNA found in bacteria that can serve as a cloning vector
Procedure for using cloning vectors • Restriction enzymes cut the plasmid open. • Donor gene is spliced in to the plasmid Specific gene isolated from another organism • Plasmid is returned to the bacterium • The gene is replicated as the bacterium is copied EACH PLASMID HAS A GENE CLONE- exact copy of gene
Transplanting Genes • Plasmids transfer a gene to a bacterium so it will produce a specific protein. EXAMPLE: INSULIN production • Large quantities are produced by inserting a human gene for insulin into a bacterium
Isolating Genes • Isolate Human DNA and Plasmid from DNA • Use Restriction Enzyme to cut DNA • Splice the DNA into the plasmid to create a GENOMIC LIBRARY Thousands of DNA pieces from a genome that have been inserted into a cloning vector 13-4a
Producing Recombinant DNA Recombinant DNA: • DNA from 2 or more sources 13-4c
DNA Technology Techniques DNA Fingerprints: • Pattern of bands made up of specific fragments from an individuals DNA. • Banding patterns can be determined how closely related different organisms are.
Making a DNA FINGERPRINT RFLP: Restriction Fragment Length Polymorphisms • Remove DNA and cut into fragments with restriction enzymes • Separate the fragments with Gel Electrophoresis • Procedure that separates nucleic acids based on size and charge.
Making a DNA Fingerprint 3. Make visible only the bands being compared. DNA fragments are blotted onto the filter paper. 4. Form PROBES : • Radioactive segments of DNA complementary to the segments being compared . • Form visible bands when exposed to photographic film. • Bands can be analyzed
Accuracy of the Fingerprints • Based on how unique the prints are • A complete DNA sequence is NOT USED, only a small portion. • VERY ACCURATE since they focus on unique regions – (non-coding areas) • They look for repeat patterns at 5 different sites. • LESS than 1 in 1 million chance of non- twins having the same patterns
PCR: Polymerase Chain Reaction • Procedure for making many copies of the selected segments of the available DNA • PIC
PCR: Polymerase Chain Reaction • A sample of DNA • A supply of the 4 DNA Nitrogen bases (A,T,C,G) • DNA Polymerase (enzyme that glues DNA) • PRIMERS: > Artificially made single strand of DNA required to initiate replication
PCR: Polymerase Chain Reaction What is needed and the procedures: 5. Incubation (with all ingredients) 6. DNA will quickly double – Every 5 minutes 7. New samples will make a DNA fingerprint 8. Only need about 50 blood cells to make a sample rather than 5,000 to 50,000 for RFLP analysis.
THE Human Genome Project THE START OF THE PROJECT: • In 1990, the National Institutes of HEALth (NIH) and the Department of ENERGY joined with international partners in a quest to sequence all 3 billion base pairs, In the human genome. • Projected to take 15 years to complete
The Human Genome Project • The Completion of the Project: • In April 2003, researchers successfully completed the Human Genome Project • Under budget and more then 2 years ahead of schedule
The Human Genome Project What have we achieved with the HGP: • Fueled the discovery of more than 1,800 disease genes • There are more than 1,000 genetic tests for human conditions
The Human Genome Project The Future: • Completion of the HapMap (a catalog of common genetic variation, or haplotypes) • Genetic factors for many common diseases, such as heart disease, diabetes, and mental illness, will be found in the next few years.
A Copy of Your Personal Genome • Currently too costly ( approx $20,000 as of July 2010) • NIH will strive to cut the cost of sequencing an individual’s genome to $1,000 or less. • Having one’s complete genome sequence will make it easier to diagnose, manage, and treat many diseases.
Individualized Care based on your Genome • Powerful form of preventive, personalized, and preemptive medicine. • Tailoring recommendations to each person’s DNA, health care professionals will be able to work with individuals to focus efforts on the specific strategies EXAMPLES: • Diet and high-tech medical surveillance
Gene Therapy • Technique that uses genes to treat or prevent disease. • Treat a disorder by inserting a gene into a patient’s cells instead of using drugs or surgery. EXAMPLES: • Replacing a mutated gene that causes disease with a healthy copy of the gene. • Inactivating, or “knocking out,” a mutated gene that is functioning improperly. • Introducing a new gene into the body to help fight a disease
Gene Therapy Successes • Nasal sprays for CF patients
Problems with Gene Therapy Gene Therapy has had limited success • It poses one of the greatest technical challenges in modern medicine • Corrected gene must be delivered to several million cells • Genes must be activated • Concern that the genes may go to the wrong cells. • Concern that germ cells (sex cells) would get the genes and be passed to offspring.
Problems with Gene Therapy 5. Immune response- body will fight off the vector as a foreign invader. 6. Gene gets “stitched” into a wrong space and knocks out an important gene Patients treated for SCID’s developed Leukemia- It was found that new gene interfered with a gene that controls the rate of cell division.
What are the Ethical Issues with Gene Therapy: • Altering GERM-LINE (sex cells) • Genetic enhancement • Concerns with past practices of EUGENICS- Adolf Hitler eu·gen·ics The study of hereditary improvement of the human race by controlled selective breeding.
Producing Pharmaceutical Products • Can be produced more inexpensively INSULIN: produced in bulk by bacteria
Genetically Engineered Vaccines • VACCINE: Harmless version of a virus or bacterium • DNA technology may produce safer vaccines
Increasing Agricultural Yields • Can insert genes into plants to make them resistant to pests • Crops that don’t need fertilizer • Ex: Genetically enhanced tomatoes that ripen without becoming soft
Concerns with Genetically Engineered Foods • FDA requires scientific evidence that allergy- inducing properties have not been introduced into the food. • If a food contains a new protein, carbohydrate, or fat it must be approved by the FDA for sale. • Concerns that they could spread creating “SUPERWEEDS”
Super Weed Biotechnology. A wild plant that has been accidentally pollinated by a genetically-modified plant and now contains that plant's abilities to resist herbicides and insects • Examples of Super weeds