DNA Technology Notes

Genetic Engineering Genetic Engineering – making changes in the DNA code DNA Manipulation: 1.Cells are opened and the DNA is separated from other cell parts 2. Biologists cut the DNA into smaller fragments using restriction enzymes which cut the DNA at a specific sequence of nucleotides

Gel Electrophoresis 3. Using gel electrophoresis, a mixture of DNA fragments is placed at one end of a porous gel. When electric voltage is applied, DNA (negatively charged) move toward the positive end of the gel. The smaller the DNA fragment, the faster and farther it moves!

DNA fingerprinting Can you determine who the father is?

CSI: Who is the Dad? Can you determine who the father is?

DNA Fingerprinting and Endangered Species DNA can identify endangered or protected animals. The DNA from endangered animals has been preserved in banks. For example, DNA from grizzly bears has been banked to help these declining animals preserve a healthy genetic pool.

Cell Transformation- Transforming Bacteria (recombinant DNA) During transformation, a cell takes in DNA from outside the cell. This external DNA becomes a component of the cell’s DNA. Free DNA Transformed Bacterium Plasmid + DNA Bacterium Plasmid

Cell Transformation In bacteria, the circular DNA molecule is known as a plasmid. Plasmid DNA has two essential features: 1. Its DNA sequence helps promote plasmid replication. 2. If the plasmid containing the foreign DNA manages to get inside a bacterial cell, this sequence ensures that it will be replicated.

Bacterial Transformation

Why is Transforming Bacteria Important? When organisms contains genes from another species, they are called transgenic. Transgenic bacteria now produce important substances useful for health and industry. These transformed bacteria produce proteins cheaply, quickly, and abundantly. Examples are human insulin for people with diabetes, growth hormones and clotting factor for people with hemophilia.

Examples of Other Transgenic Organisms (Genetically Modified Organisms): Transgenic Animals- laboratory mice have been produced with human genes to that their immune systems are similar to humans. This way scientists can study human diseases by using mice. Some livestock have extra copies of growth hormone genes which allows them to grow faster and have leaner meat.

Gene causes these mice to glow in the dark. Normally, the gene is found in jellyfish.

How Did They Do That? 1.The jellyfish has a gene that makes a glowing protein. This makes the jellyfish glow in some types of light. 2.The glowing gene is taken from a jellyfish cell and spliced (inserted) into an empty virus cell (with no bad virus in it) 3.The genetically engineered virus attaches itself to the fertilized mouse egg cell. 4.The virus delivers the glowing gene into the egg cell nucleus, where it joins the mouse DNA. 5.The genetically engineered mouse egg grows into an adult mouse which will make the glowing protein. The glow is too faint to see under normal lights but can be detected using a special camera. Virus Jellyfish cell Mouse cell Virus inserting their DNA into a cell

What’s Been Done So Far? Genetically engineering chickens so they have no feathers – why? Genetically engineering mice so they have no fur – why? Genetically engineering salmon (fish) so they grow much faster than normal salmon – why? 00/04/11/61.asp 00/04/11/61.asp Glowing mice

Examples of Other Transgenic Organisms (GMO’s): Transgenic Plants Plants can contain genes that produce a natural insecticide so that plants do not have to be sprayed. In the future, plants could produced human antibodies to help fight diseases.

This diagram shows how one type of GM food, a strawberry that resists frost damage is made. The flounder is a fish that live in icy seas. It has a gene that stops it from freezing to death.Strawberries are soft fruits that can easily be damaged by frost. 1. The flounder’s antifreeze gene is copied and inserted into a small ring of DNA taken from a bacteria cell. 2. The DNA ring containing the flounder gene is put into a second bacterium. 3. This second bacterium is used to infect the strawberry cell. The flounder’s antifreeze gene enters the strawberry’s DNA. Strawberry cell with Antifreeze gene 4. The new GM strawberry cell is grown into a GM strawberry plant which can be bred many times. Thanks to the new gene, GM strawberries make a protein which helps them resist frost. They don’t contain any other fish genes and, and do not taste or smell of fish. Wonder what they used to make this one green!

Examples of Other Transgenic Organisms: A rice plant has been developed to contain vitamin A, a nutrient that is essential for our health. Rice is a major food source for billions of the world’s population

What Have I Eaten? Genetically modified (GM) foods possess specific traits such as tolerance to herbicides or resistance to insects or viruses. By most estimates, up to 70% of the processed foods at your local grocery store contain at least one ingredient that’s been genetically altered Genetically modified to reduce being eaten by insects. Genetically modified to travel better so don’t have to be picked when green – better tasting! Click GMO food listfood

What Else? Using the jellyfish protein to make a naturally glowing Christmas tree! Genetically engineered moths that pass on deadly disease genes to their relatives so they die and won’t be able to destroy crops! Adding a gene from insect killing bacteria to cotton so that insects who eat cotton will be poisoned! A gene from a spider has been inserted into some goats. Their milk now contains tiny strands of spider silk which can be made into a strong, stretchy rope.

How can we use genetically engineering to help us? By inserting a gene for human insulin into an E.Coli bacterium, the E. coli will make lots of insulin, which scientists and doctors can collect and use. Right now, doctors are using pig hearts for transplants but there are still rejection problems. One day soon, scientists will be able to genetically engineer pigs to grow human organs for use in transplants.

Pros and Cons of GMO’s Crops Better taste and quality Less time to ripen. More nutrients, more food, and stress tolerance Improved resistance to disease, pests, and herbicides New products and growing techniques Animals Increased resistance, productivity, hardiness, and feed efficiency Better yields of meat, eggs, and milk Improved animal health and diagnostic methods Environment "Friendly" bioherbicides and bioinsecticides Conservation of soil, water, and energy Better natural waste management More efficient processing Society More food for growing populations Safety Potential human health impact: allergens, transfer of antibiotic resistance markers, unknown effects Potential environmental impact: unintended transfer of transgenes through cross-pollination, loss of flora and fauna biodiversity Access and Intellectual Property Domination of world food production by a few companies Increasing dependence on Industralized nations by developing countries Ethics Violation of natural organisms' intrinsic values Tampering with nature by mixing genes among species Objections to consuming animal genes in plants and vice versa Stress for animal Labeling Not mandatory in some countries (e.g., U. States) Mixing GM crops with non-GM confounds labeling attempts

23 Human Genome Project Started in 1990 Research effort to sequence all of our DNA (46 chromosomes) Over 3.3 billion nucleotides Mapping every gene location (loci) Conducted by scientists around the world

24 Benefits of Human Genome Project Improvements in medical prevention of disease, gene therapies, diagnosis techniques … Improvements in medical prevention of disease, gene therapies, diagnosis techniques … Production of useful protein products for use in medicine, agriculture, bioremediation and pharmaceutical industries. Production of useful protein products for use in medicine, agriculture, bioremediation and pharmaceutical industries.

Gene Therapy Gene Therapy- Gene Therapy- an absent or faulty gene is replaced with a normal, working gene.

Gene Therapy In gene therapy, viruses are often used because they have the ability to enter a cell’s DNA. The virus particles are modified so that they cannot cause disease. Then, a DNA fragment containing a replacement gene is spliced to the viral DNA. Virus

Gene Therapy The patient is then infected with the modified virus particles, which should carry the gene into cells to correct the genetic defects. Unfortunately, these experiments have not been very successful. Gene therapy remains a high-risk, experimental procedure.

Cystic Fibrosis and Gene Therapy

What is Gene Therapy? 1.In people with cystic fibrosis, one of the genes is faulty and cannot do its job properly. 2.To fix the problem, a copy of the same gene from a healthy person is spliced into a virus. 3.The patient’s lungs are infected with the virus. It delivers the working gene into the patient’s cells. The cells can then make the right protein, and the patient can breathe normally. Patient’s cell Patient’s DNA Faulty Gene Virus DNA New working gene Patient’s DNA Virus DNA with new gene

Severe Combined Immunodefiency (aka “Bubble Boy”) In 1990, SCID was the first illness treated by gene therapy. The normal gene was transferred into the defective white blood cells to compensate for the genetic mutation.

Cloning A clone is a member of a population of genetically identical cells produced from a single cell. Researchers hope that cloning will enable them to make copies of transgenic animals to help save endangered species.

How to Clone a Sheep

Cloning a Human

Cloning This technology is controversial because some studies suggest that cloned animals may suffer from genetic defects and health problems. Cloning in humans raises serious ethical and moral issues. cfm?guidAssetId=f91a792d-3f8f f60000b1df&productCode=HUB