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Warm-up

L.95 What is the difference between:

1. a mastectomy and a mammography?2. Living will and durable power of attorney?3. CT scan and MRI?4. Preciptin test and Kastle Meyer test?5. CDC and WHO?6. Allocation and procurement?7. In situ cancer and invasive cancer?8. Radiographer and radiologist?9. Applied research and clinical research?10.Random Question: If a patient weighs 165

pounds, how many grams does he weigh?

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Transgenic Animals

Introduction

• Over the past few decades, human and nonhuman animals have benefited from biotechnology.

• For thousands of year, we have conducted selective breeding to improve our livestock.

• 50 years after the structure of DNA was first discovered, scientists use some of those same microorganisms to produce human hormones and improve our livestock and crops.

What are transgenic organisms?

• Organisms which contain other species’ genes within their chromosomes.

• In order to produce a transgenic animal, scientists inject a transgene into a single cell organism.

Interesting Fact:

• The first transgenic organisms were bacteria because they are the simplest forms of life.

• They are still used by pharmaceutical companies today to produce a variety of human proteins such as insulin and human growth hormones.

Use of transgenic techniques in animals:

• Models of human disease• A way to improve the quality and health of

livestock• Another method to produce

pharmaceuticals • A source of organs for humans• A model for gene therapy in humans (e.g.,

substituting the normal gene for hemoglobin to replace the one that causes sickle cell anemia.

First Transgenic Animal

• 1975 – implanted an ape gene into a mouse.

• The mouse produced the ape protein but did not pass the gene onto offspring.

• Two years later, the same researchers produced the first transgenic mouse strain, whose offspring did contain the implanted transgene.

Success and growing

• Transgenic animal production increased rapidly in the 1980s as scientists improved genetic engineering techniques and identified and purified more genes.

The approval process:

• Biomedical researchers must go through an approval process to create a transgenic animal by applying for a patent from the US Patent and Trademark Office.

Benefits of Transgenic Animals

Animal models

• They reproduce quickly• They are small animals and therefore

easily housed.• Their genetic makeup is better understood

than other mammals• Their lifespan is 2-3 years, allowing

researchers to follow disease processes from infancy to old age over a relatively short time.

Animal models cont.

• Hundreds of mouse strains already exist with spontaneous genetic mutations (flaws within their genes) that resemble human diseases (diabetes, dwarfism).

• By producing genetically engineered mutations, scientists have more control over what genes they are studying and don’t have to wait for spontaneous mutations to appear.

Pharmaceutical production

• It is reproducible• The amount of drug produced is limited

only by the number of successful transgenic animals produced and its offspring.

• Maintaining the animal is more economical, compared to the amount of drug produced, than growing cells in tissue culture.

Organ donors

• Successful because physicians have an arsenal immosuppressive drugs.

• Alternative: using xenografts’ (pigs)• Improving the success rate because of

body’s want to reject these organs.• Carry few infectious agents• Reproduce quickly and have large litters• Less social opposition to using pigs than

to using non-human primates

Livestock improvement

• Transgenic technology could produce animals that are larger, leaner, more efficient at using feed, or more resistant to disease.

• Safety of meat or dairy products – people strongly oppose the products of transgenic animals

Care of Transgenic Animals

• Do not require special care

• Sometimes have a disorder that makes them susceptible to disease.

• Scientists use only the healthiest animals and do their best to keep the animals healthy.

Against Transgenics?

• There are many ethical considerations to the opposition of transgenic animals:– Animal welfare– “Playing God”– Use the techniques in humans– Threaten our environment, health, food supply

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Processing

L.95 Processing

• Now that you know what transgenic animals are, draw a caricature that represents what a transgenic is.

• Make it colorful and creative.