Let s Review! Genetics: So far

Transcription

1 Let s Review! Genetics: So far

2 What you are expected to know Historical Contributions Mutations Dominant and Recessive Traits Genotypes and phenotypes Punnett Squares Nature vs. Nurture Genetic Engineering Describe the contributions of Mendel, Franklin, Watson, and Crick. Identify the causes and effects of mutations on an organism. Distinguish between dominant and recessive traits. Distinguish between genotype and phenotype Use Punnett Squares to show the possible combinations of inherited factors resulting from a single trait cross. Explain the relationship between characteristics that can and cannot be inherited. Identify aspects of genetic engineering and supply examples of applications. Evaluate the examples for possible controversial aspects.

3 Franklin/ Watson and Crick

4 Historical Contributions of Scientists Gregor Mendel - known as the Father of Genetics. He is known for his scientific investigation involving pea plants. Rosalind Franklin - developed the first x-ray image of DNA. Watson and Crick - constructed the first 3-D model of DNA (The double helix).

5 Mendel, the Musical

6 Mutations Errors in DNA replication cause mutations. Errors can be caused by one of two processes: Mistakes that occur when a cell copies its DNA in preparation for cell division. DNA damage from environmental agents such as ultraviolet light (sunlight), nuclear radiation, X-rays, or certain chemicals (some medications)

7 Distinguish between dominant and recessive traits Dominant traits require at least one dominant gene for the trait to be expressed. Recessive traits require two recessive genes.

8 Genotypes and Phenotypes A genotype is the set of genes an organism carries A genotype is represented with paired letters to show the actual gene pair. Upper case for dominant genes, lower case for recessive genes. Example: genotype for blue eyes bb The Phenotype is the visible expression of the trait. Think what is Physically seen or a Photograph. Example: phenotype for blue eyes

9 A single trait can be influenced by more than one gene pair resulting in a variety of phenotypes.

10 Punnett Squares: Show the possible combinations of gene pairs of the offspring. Who studied pea plants?

11 Nature verses Nurture Are certain personality traits predisposed in our DNA (Nature) or influenced by experiences and the environment in which one is taught (Nurture)? Are we born this way or behave due to life experiences???

12 And now the new notes Genetic Engineering Genetic engineering is a rapidly advancing field of science which can currently be used to treat diseases, produce food, and manipulate cells. Many other applications may be possible in the future.

13 GENETIC ENGINEERING What is it? What are the advantages (pros) and disadvantages (cons)? What is your opinion?

14 Genetic Engineering Means making changes to DNA in order to change the way living things work. Creates new crops and farm animals Make bacteria that can make medicines Grow human body parts Prevent genetic diseases, change humans

15 Genetic Engineering Genetic Engineers can alter the DNA code of living organisms. Selective Breeding Recombinant DNA Gel Electrophoresis Transgenic Organisms

16 What are Genetically Modified Foods? (Also called Genetically Modified Organisms GMO s) You have already eaten GM foods. Some GM tomatoes, for example, have had their genes altered to stop them from going soft while they are still growing. For several years they were widely sold in tomato paste. The GM foods we eat have all been tested for safety. But some people worry about the long term effects of eating genetically modified foods!

17 How does it work? In cross pollination (think Mendel s peas), we are combining two traits to get a mixture of results In genetic engineering, a single gene, a half page recipe in the 52-thousand-page set of recipe books, can direct the plant to make new traits or remove them

18 Can We End World Hunger? Malnutrition and Vitamin Deficiencies? Golden rice is genetically modified rice that now contains a large amount of A-vitamins. Or more correctly, the rice contains the beta-carotene which is converted in the body into Vitamin-A. So when you eat golden rice, you get more vitamin A. Beta-carotene gives carrots their orange color and is the reason why genetically modified rice is golden. For the golden rice to make betacarotene three new genes are implanted: two from daffodils and the third from a bacterium Advantages: The rice can be considered a particular advantage to poor people in underdeveloped countries. They eat only an extremely limited diet lacking in the essential bodily vitamins. The consequences of this restricted diet causes many people to die or become blind. This is particularly true in areas of Asia, where most of the population live on rice from morning to evening. Are there any disadvantages?

19 Pros and Cons 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" bio-herbicides and bio-insecticides 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 crosspollination, loss of flora and fauna biodiversity Access and Intellectual Property Domination of world food production by a few companies Increasing dependence on Industrialized 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

20 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? Glowing mice

21 What s Next? Red fish, blue fish, yellow fish, GLOW FISH?

22 How Did They Do That? Virus Mouse cell Jellyfish cell Virus inserting their DNA into a cell 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.

23 Axolotls With GFP

24 What Else? Using the jellyfish protein to make a naturally glowing Christmas tree! Adding a gene from insect killing bacteria to cotton so that insects who eat cotton will be poisoned! Genetically engineered moths that pass on deadly disease genes to their relatives so they die and won t be able to destroy crops! 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.

25 How can we use genetic engineering to help us? 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. 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.

26 Genetic engineering examples include taking the gene that programs poison in the tail of a scorpion, and combining it with a cabbage. These genetically modified cabbages kill caterpillars because they have learned to grow scorpion poison (insecticide) in their sap. Genetic engineering also includes insertion of human genes into sheep so that they secrete alpha-1 antitrypsin in their milk - a useful substance in treating some cases of lung disease. Genetic engineering works because there is one language of life: human genes work in bacteria, monkey genes work in mice and earthworms. Tree genes work in bananas and frog genes work in rice. There is no limit in theory to the potential of genetic engineering!

27 Time for Chickens with 6 wings

28 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

29 Will We Be Able To Cure Cancer With Gene Therapy? Cancer happens when body cells grow out of control. Scientists have found a gene called p-53 which normally keeps cells under control. They think that in some people with cancer, the disease begins because the p-53 gene doesn t work properly perhaps because of a mistake in the gene code. Experts are now looking for a way to cure cancer by modifying faulty DNA to make the p-53 gene work. Lung cancer cells (530x). These cells are from a tumor located in the alveolus (air sac) of a lung.

30 Let's begin with what this is not. This is not a human ear growing on a mouse. This is a piece of cow cartilage that is in the shape of a human ear. For doctors, growing cartilage in the right shape for ear reconstruction is difficult. Dr. Charles Vacanti in 1997 created a biodegradable scaffold seeded with cow cartilage cells. Implanted in a nude mouse, the animal's blood vessels nourished the cartilage cells until they grew to replace the simultaneously dissolving scaffold. This piece of cartilage was never implanted in a human cow cartilage, after all, would be rejected by a normal immune system

31 Cow Gives Birth To A Bison Hijacking a womb by one species for another Scientists at Massachusetts Advances Cell Technology (ACT) have succeeded in cloning a gaur, an ox-like animal under threat of extinction in Southern Asia. They used the "Dolly the sheep" animal cloning technique to create 81 cloned embryos after 692 attempts using gaur skin cells and cow's eggs. These cloned embryos were then implanted into cows, with 8 pregnancies, five miscarriages and three expected live births. (Source Guardian 7 October 2000) The next step by ACT will be to clone the first extinct animal, the bucardo. Scientists discovered the last animal dead, but in time to freeze and preserve tissue samples for animal cloning.

32 Thinking time. As 7 th grade Virginia Beach students you need to Identify aspects and applications of genetic engineering. Also, evaluate the examples for possible controversial aspects.

33 Right or Wrong? Arguments for creating designer babies Some couples are not able to have children because their children will have a genetic disease and die before they are born or when they are very young. Techniques used to change the genetic make-up of the embryo allow these parents to have a child. If we want the best for our children why shouldn't we design our own babies? Using genetic techniques we can help prevent certain genetic diseases. This both saves the children from suffering and reduces the cost and emotional strain of looking after an ill child. Will this lead to happier children and parents? Spare part children? In a few cases where parents have had one child with a serious blood disease, they have used IVF to select embryos so that they can have a second child that can act as a future, tailor-made blood or bone marrow donor. In these cases when the child is born he or she will be healthy and can help their older brother or sister stay well.

34 Arguments against creating designer babies But is this right? In these cases, parents and doctors are creating a child to act as an organ-donating factory. How will the child feel? The child may feel that they were only born to be a help to their older brother or sister. Children should be loved and cherished for themselves and not what they can do for others. These genetic techniques are very expensive. Why should only rich people be able to eradicate genetic diseases? This could lead to imbalances between rich and poor people. Will we breed a race of super-humans who look down on those without genetic enhancements? Even today people who are born with disabilities face intolerance. Will discrimination against people already born with disabilities increase? We could get carried away 'correcting' perfectly healthy babies. Once we start to eliminate embryos because they have the gene for a disease, what is to stop us from picking babies for their physical or psychological traits? At the moment we can screen human embryos to choose only those embryos without the 'bad' genes. But is it right to add new artificial genes, or take away other genes? These genetic changes will be permanent and be contained in every single cell of the baby. Alterations made by genetic engineering would be passed on from one generation to the next. What right have parents to choose what genetic characteristics are best for their children, and their children's children. Will the children react against the genetic changes that their parents have chosen for them? Who is responsible for genetic modification of a child? The parents? The doctors? Or the Government?

35 What do you think? Should parents be allowed to custom build their children? Will it lead to happier parents and children? Will it lead to healthier people? Will it lead to more beautiful people? Will it lead to there being more differences between rich and poor people? Should scientists tamper with the genes of unborn children to cure genetic disease? Is it right? Is it unnatural?

36 Genetically Modified Foods

37 Genetic Engineering Problems

38 Genetic engineering to music

39 Genetic engineering in cotton (Bt)

40 ANDi A year ago, scientists at the Oregon Regional Primate Research Center announced the birth of the first genetically engineered primate, named ANDi (for "inserted DNA" spelled backwards), a rhesus monkey whose cells contained the gene that makes jellyfish glow in the dark. The experiment was something of a flop; ANDi does not glow. (Rodents implanted with the gene do.) But imagine that one day science does acquire the skills to make "designer babies," that the connections between genes and complex traits such as intelligence or musical ability are finally known. While only the weirdest of parents would to want to genetically engineer offspring with jellyfish genes, others would undoubtedly jump at the chance to "customize" their children with a sparkling personality, brains, and beauty.

41 Though cloning is not genetic engineering, in the sense that no DNA is being changed, it has pros and cons also

42 Now cats may have more than nine lives. The company that funded the first successful cloning of a domestic cat two years ago has gone commercial. The cost? U.S. $50,000 each.

43 In most cases, owners want to clone their pets because they're experiencing difficulty dealing with the loss, or eventual loss, of those pets, according to the Humane Society of the United States (HSUS), an animal-protection group based in Washington, D.C. But given that shelters kill roughly four million animals each year because they're not adopted, HSUS feels cloning new pets should not be done. The group encourages people who want a cat or dog to adopt one from a local shelter. The company is also working on duplicating dogs specifically, a husky mix named Missy, whose owner, Arizona entrepreneur John Sperling, has pumped millions of dollars into the cloning project since it began in Missy died at age 15 in 2002, but tissue samples of her have been saved for cloning purposes.

44 So, what about that woolly mammoth Discovering frozen woolly mammoth tissue, offers the tantalizing prospect of using extracted DNA to clone a new one. Such ideas have long been the preserve of science fiction, but can it realistically be accomplished? Proffessor Adrian Lister, a paleontologist at the Natural History Museum, in London, doesn't think so, Because the remains of these animals have been buried for thousands of years, the DNA has become fragmented and shattered. You've got an alphabet soup of bits and pieces of DNA left in that frozen tissue."

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46 One more thought Do you believe that meat you buy at the grocery store should be DNA tested?

47 Wal-Mart recalls 'Five Spice' donkey meat in China after tests reveal fox By Adam Jourdan, Reuters SHANGHAI, China -- Wal-Mart Stores Inc has recalled donkey meat sold at some outlets in China after tests showed the product contained the DNA of other animals. Wal-Mart will reimburse customers who bought the tainted "Five Spice" donkey meat and is helping authorities in eastern Shandong province investigate its Chinese supplier, the firm said late on Wednesday on China's Twitter-like Weibo. The Shandong Food and Drug Administration earlier said the product contained fox meat. The scandal could dent Wal-Mart's reputation for quality in China's $1 trillion food and grocery market where it plans to open 110 new stores in the next few years. China is the largest grocery market in the world and is set to grow to $1.5 trillion by 2016, according to the Institute of Grocery Distribution.

48 Some officials believe only the tip of the iceberg has been revealed, and on Friday the European Union endorsed a major DNA-testing program to establish just how much unlabeled horse meat is being sold as beef or other foods. Fraud on a massive scale': Europe's horse meat scandal keeps on growing A laboratory assistant prepares a sample of lasagna for a DNA test at a veterinary research facility in Germany. By Ian Johnston, Staff Writer, NBC News LONDON -- When officials in Ireland made a routine check on a few hamburgers, what they found made them nervous: One burger was actually nearly one-third horse. It was a discovery that has sent shock waves reverberating across Europe. Since the disturbing DNA test results were disclosed last month, horse meat has been found masquerading as beef in countries including the U.K., France, Germany, Sweden and Norway.

49 Fun clip on organic foods

50 Jane is blind and has a guide dog called Bobby. Bobby has been her guide dog for 10 years but is getting old. Bobby is Jayne s best friend and she feels that without him she couldn t live. Should Jayne be allowed to clone Bobby before he dies? Should people be allowed to clone their pets? The year is 2025, there is only one Giant Panda left on earth. It does not have a partner to breed with, so once it dies the species will be extinct. Should scientists be allowed to clone another Giant Panda to keep the species alive? Should scientists be allowed to clone endangered species?

51 Cloning HUMANS? British scientists say they have cloned the country's first human embryo. The Newcastle University team took eggs from 11 women, removed the genetic material and replaced it with DNA from embryonic stem cells. The aim of this kind of work - the subject of fierce debate - is to make cloned embryos from which stem cells can be used to treat diseases. Meanwhile South Korean scientists say they have created stem cells to match individuals for the first time. Stem cell lines were created by taking genetic material from the patient and putting it into a donated egg. The resultant cells were a perfect match for the individual and could mean treatments for diseases like diabetes without problems of rejection. Therapeutic cloning - believed to have huge potential to treat disease and disability - is allowed in Britain. Reproductive cloning - the cloning of human embryos with the intention of creating a baby - was made illegal in 2001.

52 In Minnesota last year researchers at the Mayo Clinic created pigs with human blood flowing through their bodies. And at Stanford University in California an experiment might be done later this year to create mice with human brains. Scientists feel that, the more humanlike the animal, the better research model it makes for testing drugs or possibly growing "spare parts," such as livers, to transplant into humans.

53 Rat called Ralph is latest clone Scientists have succeeded in cloning the rat. The researchers from China and France say they managed to create several rodent copies - both male and female. The rat joins a lengthening list of animals that have been cloned from an adult cell. These include sheep, mice, cattle, goats, pigs, cats, mules and horses. The rat has come later than the others because of unique difficulties in controlling the development of its eggs in the early stages of the cloning process. Rat eggs activate almost immediately they leave the ovaries, making it difficult to introduce the genetic material of the animal to be copied.

54 Mrs. Jones eldest son Mark is 10 years old and is dying with cancer. Should Mrs. Jones be allowed to clone Mark before he dies? Should people be allowed to clone other humans or clone themselves? John Green is a farmer in Texas and he wants to clone his prize bull to sell it and make money. Should farmers be allowed to clone their best animals to make money? A developing country with food shortages want to clone their best food producing animals, cows, chickens, pigs etc. to try and produce more food per animal to solve their food shortages. Should countries be allowed to clone animals to increase food production.