Biotechnology 1. DNA Technology: Discussion 2 Biotechnology Products The use of technology to alter...

BiotechnologyBiotechnology

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DNA Technology: DNA Technology: DiscussionDiscussion

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Biotechnology ProductsBiotechnology Products

• The use of technology to alter the genomes of viruses, bacteria, and other cells for medical or industrial purposes is called genetic engineering.

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Biotechnology ProductsBiotechnology Products

• Organisms that have had a foreign gene inserted into them are called transgenic organisms. (TRANSferred GENE = TRANS GENIC)

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DNA technology is changing the DNA technology is changing the pharmaceutical industry and pharmaceutical industry and

medicinemedicine• Therapeutic Hormones Consider human insulin

and human growth hormone (HGH). • In the United States alone, about 2 million people

with diabetes depend on insulin treatment. • Before 1982, the main sources of this hormone

were pig and cattle tissues obtained from slaughterhouses.

• Insulin extracted from these animals is chemically similar, but not identical, to human insulin, and it causes harmful side effects in some people.

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DNA technology is changing the DNA technology is changing the pharmaceutical industry and pharmaceutical industry and

medicinemedicine• Genetic engineering has largely solved this

problem by developing bacteria that synthesize and secrete actual human insulin.

• In 1982, Human growth hormone was urgently needed. In 1985, molecular biologists were able to produce HGH in bacteria.

• Before this genetically engineered hormone became available, children with a HGH deficiency had to rely on scarce supplies from human cadavers or else face dwarfism.

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Human insulin produced by bacteria

– In 1982, Humulin became the first recombinant drug approved by the Food and Drug Administration

Figure 12.7A 7

Table 12.6 8

Biotechnology Products Biotechnology Products From BacteriaFrom Bacteria

• Recombinant DNA technology means to recombine the DNA of an organism to make it more useful to humans.

• It is used to produce bacteria that reproduce in large vats to get them to make a large amount of a particular protein, such as insulin, growth hormone, clotting proteins for hemophiliacs, and hepatitis B vaccine.

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Hepatitis B VaccineHepatitis B Vaccine

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VaccinesVaccines• DNA technology is also helping medical

researchers develop vaccines. • A vaccine is a harmless variant or derivative of a

pathogen (usually a bacterium or virus) that is used to prevent an infectious disease.

• When a person is inoculated, the vaccine stimulates the immune system to develop lasting defenses against the pathogen.

• For the many viral diseases for which there is no effective drug treatment, prevention by vaccination is virtually the only medical way to prevent illness.

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VaccinesVaccines• One DNA technology vaccine is for

the hepatitis B virus. • Hepatitis is a disabling and

sometimes fatal liver disease, and the hepatitis B virus may also cause liver cancer.

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VaccinesVaccines• Smallpox was once a dreaded human

disease, but it was eradicated worldwide in the 1970s by widespread vaccination with a harmless variant of the smallpox virus.

• In fact, the harmless virus could be engineered to carry the genes needed to vaccinate against several diseases simultaneously.

• In the future, one inoculation may prevent a dozen diseases.

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VideoVideo• Recombinant DNA Technology

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• Transgenic bacteria can also help plants. For example, bacteria that live in plants have genes spliced in that let them resist insect toxins; this protects the roots of the plants, too.

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Biotechnology Biotechnology Products Products

From BacteriaFrom Bacteria

• Bacteria can be genetically engineered to degrade a particular substance, for instance, transgenic bacteria have been produced which have the ability to eat oil after an oil spill.

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• Industry has found that bacteria can be used as filters to prevent airborne chemicals from being vented into the air.

• They can also remove sulfur from coal before it is burned and help clean up toxic dumps.

• Furthermore, these bacteria were given “suicide” genes that caused them to self-destruct when the job is accomplished.

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• Many major mining companies already use bacteria obtain various metals.

• Genetic engineering may enhance ability of bacteria to extract copper, uranium, and gold.

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Biotechnology Products Biotechnology Products From PlantsFrom Plants

• Plants can also be genetically engineered to make cotton, corn, soybeans, and potatoes resistant to pests because their cells now produce an insect toxin.

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Biotechnology Products Biotechnology Products From PlantsFrom Plants

• Plants are also being engineered to produce human hormones, clotting factors, and antibodies, in their seeds.

• One type of antibody made by corn can deliver a substance that kills tumor cells, and another made by soybeans can be used as treatment for genital herpes.

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Genetically modified Genetically modified organisms are transforming organisms are transforming

agricultureagriculture• Scientists concerned with feeding the

growing human population are using DNA technology to make genetically modified (GM) organisms for use in agriculture.

• A GM organism (Or GMO) is one that has acquired one or more genes by artificial means rather than by traditional breeding methods. (The new gene may or may not be from another species.)

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agricultureagriculture• To make genetically modified plants,

researchers can manipulate the DNA of a single cell and then grow a plant with a new trait from the engineered cell.

• Already in commercial use are a number of crop plants carrying new genes for desirable traits, such as delayed ripening and resistance to spoilage and disease.

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agricultureagriculture• The most common vector used to

introduce new genes into plant cells is a piece of DNA from a soil bacterium.

• With the help of a special enzyme, the gene for the desired trait is inserted into a plant cell, where it is integrated into a plant chromosome.

• Finally, the re combinant cell is cultured and grows into a whole plant.

• If the newly acquired gene is from another species, the recombinant organism is called a transgenic organism.

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agricultureagriculture• Genetic engineering is rapidly replacing

traditional plant-breeding programs.• For example, the majority of the American

soybean and cotton crops are genetically modified.

• Many of these GM plants have received bacterial genes that make the plants resistant to herbicides or pests.

• Farmers can more easily grow these crops with far less tillage and reduced use of chemical insecticides.

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agricultureagriculture• Genetic engineering also has great

potential for improving the nutritional value of crop plants.

• “Golden rice,” a transgenic variety with a few daffodil genes, produces grains containing beta-carotene, which our body uses to make vitamin A.

• This rice could help prevent vitamin A deficiency—and resulting blindness—among the half of the world’s people who depend on rice as their staple food.

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Colored CottonColored Cotton• Discovery Channel Video Clip

– On your textbook CD– Chapter 32– At the bottom of the page

• “EXTEND YOUR KNOWLEDGE”

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Biotechnology Products Biotechnology Products From AnimalsFrom Animals

• Agricultural researchers are also making transgenic animals. To do this, scientists first remove egg cells from a female and fertilize them in vitro. They then inject a previously cloned gene directly into the nuclei of the fertilized eggs. Some of the cells integrate the foreign DNA into their genomes. The engineered embryos are then surgically implanted in a surrogate mother. If an embryo develops successfully, the result is a transgenic animal, containing a gene from a third “parent” that may even be of another species.

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• The procedure has been used to produce larger fish, cows, pigs, rabbits, and sheep.

• Genetically engineered fishes are now being kept in ponds that offer no escape to the wild because there is much concern that they will upset or destroy natural ecosystems.

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Transgenic PigTransgenic Pig

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• The goals of creating a transgenic animal are often the same as the goals of traditional breeding—for instance, to make a sheep with better quality wool or a cow that will ma ture in a shorter time. Scientists might, for example, identify and clone a gene that causes the development of larger mus cles (muscles make up most of the meat we eat) in one vari ety of cattle and transfer it to other cattle or even to sheep.

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• Transgenic animals also have been engineered to be phar maceutical “factories” that produce otherwise rare biological substance for medical use. Recently, researchers have engineered transgenic chickens that express large amounts of the foreign product in their eggs. This success suggests that transgenic chickens may emerge as relatively inexpensive pharmaceutical facto ries in the near future.

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• Gene pharming is the use of transgenic farm animals to produce therapeutic drugs in the animal’s milk.

• There are plans to produce drugs for the treatment of cystic fibrosis, cancer, blood diseases, and other disorders.

• An anti-clotting medicine is currently being produced by a herd of goats.

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Pharm AnimalsPharm Animals

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• Animals have been engineered to produce growth hormone in their urine instead of in milk.

• Urine is preferable to milk because only females produce milk, and not until maturity, but all animals produce urine from birth.

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XenotransplantationXenotransplantation

• Scientists have begun the process of genetically engineering animals to serve as organ donors for humans who need a transplant.

• We now have the ability to transplant kidneys, heart, liver, pancreas, lung, and other organs.

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XenotransplantationXenotransplantation

• Unfortunately, however, there are not enough human donors to go around.

• Fifty thousand Americans need transplants a year, but only 20,000 patients get them.

• As many as 4,000 die a year while waiting for an organ.

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XenotransplantationXenotransplantation• You might think that apes, such as

the chimpanzee or the baboon might be a scientifically suitable species for this purpose.

• But apes are slow breeders and many people object to using apes for this purpose.

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XenotransplantationXenotransplantation• In contrast, pigs have been an acceptable

meat source, and a female pig can become pregnant at six months and can have two litters a year, each averaging about ten offspring.

• Ordinarily, the human body rejects transplanted pig organs.

• Genetic engineering, however, can make pig organs good for transplantation at less of a rejection risk.

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Cloning of AnimalsCloning of Animals• Imagine that an animal has been

genetically altered to serve as an organ donor.

• What would be the best possible way to get identical copies of this animal?

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CloningCloning

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Cloning of AnimalsCloning of Animals• If cloning of the animal was possible,

you could get many exact copies of this animal.

• Cloning is a form of asexual re production (without sex) because it requires only the genes of that one animal.

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Cloning of AnimalsCloning of Animals• In 1997, scientists at the Raslin

institute in Scotland announced that they produced a cloned sheep called Dolly.

• In 1998, genetically altered calves were cloned in the United States using the same method.

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ClonesClones

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ClonesClones

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Clone?Clone?

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Could GM organisms harm human Could GM organisms harm human health or the environment?health or the environment?

• As soon as scientists realized the power of DNA technology, they began to worry about potential dangers.

• Early concerns focused on the possibility that recombinant DNA technology might create new pathogens.

• What might happen, for instance, it cancer cell genes were transferred into bacteria or viruses?

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• To guard against such rogue microbes, scientists developed a set of guidelines that were adopted as formal government regulations in the United States and some other countries.

• One safety measure is a set of strict laboratory procedures designed to protect researchers from infection by engineered microbes and to prevent the microbes from accidentally leaving the laboratory.

• In addition, strains of microorganisms to be used in recombinant DNA experiments are genetically crippled to ensure that they cannot survive outside the laboratory.

• Finally, certain obviously dangerous experiments have been banned.

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• Today, most public concern about possible hazards centers not on recombinant microbes but on genetically modified (GM) crop plants.

• Advocates of a cautious approach fear that some crops carrying genes from other species might cause allergies in humans or create super-weeds that are hazardous to the environment.

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• Today, governments and regulatory agencies throughout the world are grappling with how to facilitate the use of biotechnology in agriculture, industry, and medicine while ensuring that new products and procedures are safe.

• In the United States, all projects are evaluated for potential risks by regulatory agencies such as the Food and Drug Administration, Environmental Protection Agency, National Institutes of Health, and Department of Agriculture.

• These agencies are under increasing pressure from some consumer groups.

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The Human Genome ProjectThe Human Genome Project

• The Human Genome Project was a massive effort to put all of the genes in human chromosomes into the proper sequence. This was just finished in 2003.

• Project goals were to identify all the 25,000 genes in human DNA and determine the sequences of the 3 billion amino acids that make up human DNA.

• This allows scientists to detect some defective genes and tailor a treatment plan to the individual.

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The Human Genome ProjectThe Human Genome Project

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Gene TherapyGene Therapy

• Gene therapy gives a patient a normal gene to make up for a faulty gene.

• For example, there is a genetic disease of the liver that causes it to malfunction and leads to high levels of blood cholesterol, which makes the patient subject to fatal heart attacks at a young age.

• The person is injected with a virus that contains the normal gene.

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Gene TherapyGene Therapy

• Another example is when fat enzymes are coated with the missing gene to cure cystic fibrosis and then sprayed into patients’ nostrils.

• Anti-cancer genes can also be injected directly into cancerous tumors.

• Perhaps it will be possible also to use gene therapy to cure hemophilia, diabetes, Parkinson disease, or AIDS.

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DiagnosisDiagnosis and Treatment and Treatment of Diseaseof Disease

• DNA technology is being used increasingly in disease diagnosis.

• It is used to determine which genes are associated with genetic diseases.

• An individual’s gene expression profile may someday allow physicians to tailor treatments for many different disorders.

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Natural Mutation in Fruit FlyNatural Mutation in Fruit Fly

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DNA technology is used DNA technology is used in courts of lawin courts of law

• DNA technology plays an important role in forensic science, the scientific analysis of evidence for crime scene and other legal investigations.

• In violent crimes, body fluids or small pieces of tissue may be left at the crime scene or on the clothes of the victim or assailant; if rape has occurred, semen may be recovered from the victim’s body.

• With enough tissue or semen, forensic scientists can determine the blood type or tissue type using older methods that test for proteins.

• However, such tests require fresh samples in relative large amounts.

• Also, because many people have the same blood or tissue type, this approach can only exclude a suspect; it cannot provide strong evidence of guilt.

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• DNA testing, on the other hand, can identify the guilty individual with a high degree of certainty because the DNA sequence of every person is unique (except for identical twins).

• DNA testing requires only about 1,000 cells. • In a murder case, for example, such analysis can

be used to compare DNA samples from the suspect, the victim, and bloodstains on the suspect’s clothes.

• They provide a DNA fingerprint, or specific pattern of bands.

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• DNA fingerprinting can also be used to establish family relationships.

• A comparison of the DNA of a mother, her child, and the purported father can conclusively settle a question of paternity.

• Sometimes paternity is of historical interest: DNA fingerprinting provided strong evidence that Thomas Jefferson or one of his close male relatives fathered at least one child with his slave Sally Hemings.

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• Just how reliable is DNA fingerprinting? • In most legal cases, the probability of two people

having identical DNA fingerprints is between one chance in 100,000 and one in a billion.

• For this reason, DNA fingerprints are now accepted as compelling evidence by legal experts and scientists alike.

• In fact, DNA analysis on stored forensic samples has provided the evidence needed to solve many “cold cases” in recent years.

• DNA fingerprinting has also exonerated many wrongly convicted people, some of whom were on death row.

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DNA Fingerprinting and the Criminal Justice System: Discussion

Defendant’sblood

Blood fromdefendant’s clothes Victim’s

blood

Figure 12.12A Figure 12.12B61

Are Genetically Are Genetically Engineered Foods Safe?Engineered Foods Safe?

DiscussionDiscussion

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Genetic Profiling: Genetic Profiling: DiscussionDiscussion

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Medicine’s Wild Medicine’s Wild Kingdom: DiscussionKingdom: Discussion

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BiotechnologyBiotechnology• Dog Genetics•

http://www.youtube.com/watch?v=K4LtTSBHjk4 (90 mins, start at 15) • Agriculture Biotechnology Products• http://www.youtube.com/watch?v=xZ9Xp-ozZzc (23 mins)

• Biotechnology Products• http://www.euronews.com/2013/06/03/biotechnology-to-fight-air-pollution/ (4 mins)

• Biotechnology Techniques• http://www.youtube.com/watch?v=A9mqwVZFCRk (14 minutes)

New Cures on the Horizon: New Cures on the Horizon: DiscussionDiscussion

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