1 / 34

Genetic Engineering

Genetic Engineering. Key concept: DNA sequences of organisms can be changed. Entire organisms can be cloned. A clone is a genetically identical copy of a gene or of an organism. Some plants clone themselves from their roots.

brian-russo
Download Presentation

Genetic Engineering

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Genetic Engineering Key concept: DNA sequences of organisms can be changed.

  2. Entire organisms can be cloned. • A clone is a genetically identical copy of a gene or of an organism. • Some plants clone themselves from their roots. • Bacteria produce identical genetic copies of themselves through binary fission. • Human identical twins are clones of each other.

  3. To clone a mammal: • Scientists swap DNA between cells with a technique called nuclear transfer. • An unfertilized egg is taken from an animal, and the egg’s nucleus is removed. • The nucleus of a cell from the animal to be cloned is implanted into the egg. • The egg is stimulated and, if successful, the egg will begin dividing.

  4. To clone a mammal (cont.): • After the embryo grows for a few days, it is transplanted into a female. • In 1997 a sheep named Dolly became the first clone of an adult mammal. • The success of Dolly led to the cloning of adult cows, pigs, and mice.

  5. Go to Click and Clone. Complete the Click and Clone worksheet.

  6. Benefits of cloning: • Scientists can use organs from cloned mammals for transplant into humans. • Cloning could help save endangered species. Cells from endangered species could be taken and used to produce clones that would increase the population of the species.

  7. Risks of cloning: • High failure rate • The enucleated egg and the transferred nucleus may not be compatible. • An egg with a newly transferred nucleus may not begin to divide or develop properly. • Implantation of the embryo into the surrogate mother might fail. • The pregnancy might fail.

  8. Risks of cloning (cont.): • Problems during later development • “Large Offspring Syndrome” • Cloned animals tend to be much bigger at birth than their natural counterparts. • Abnormally large organs that can lead to breathing, blood flow, and other problems.

  9. Risks of cloning (cont.): • Some clones without LOS have developed kidney or brain malformations and impaired immune systems, which can cause problems later in life.

  10. Risks of cloning (cont.): • Abnormal gene expressionpatterns • In a naturally-created embryo, the DNA is programmed to express a certain set of genes. Later on, as the embryonic cells begin to differentiate, the program changes. For every type of differentiated cell (skin, blood, bone, etc.), this program is different.

  11. Risks of cloning (cont.): • In cloning, the transferred nucleus doesn’t have the same program as a natural embryo. It is up to the scientist to reprogram the nucleus. • Complete reprogramming is needed for normal or near-normal development. • Incomplete programming will cause the embryo to develop abnormally or fail.

  12. Risks of cloning (cont.): • Telomeric differences • As cells divide, their chromosomes get shorter. This is because the DNA sequences at both ends of a chromosome, called telomeres, shrink in length every time the DNA is copied. • The older the animal is, the shorter its telomeres will be. This is a natural part of aging.

  13. Risks of cloning (cont.): • When scientists looked at the telomere lengths of cloned animals, they found no clear answers. • Chromosomes from cloned cattle or mice had longer telomeres than normal. These cells showed other signs of youth and seemed to have an extended lifespan compared with cells from a naturally conceived cow.

  14. Risks of cloning (cont.): • On the other hand, Dolly the sheep’s chromosomes had shorter telomere lengths than normal. This means that Dolly’s cells were aging faster than the cells from a normal sheep. • To date, scientists aren’t sure why cloned animals show differences in telomere length.

  15. New genes can be added to an organism’s DNA. • Genetic engineering is the changing of an organism’s DNA to give the organism new traits • Possible because the genetic code is shared by all organisms. • Based on the use of recombinant DNA, which is DNA that contains genes from more than one organism

  16. New genes can be added to an organism’s DNA (cont.). • Benefits of recombinant DNA: • Could be used to produce crop plants that make medicines and vitamins • Scientists are studying ways of using recombinant DNA to make vaccines to protect against HIV

  17. New genes can be added to an organism’s DNA (cont.). • Bacteria are commonly used in genetic engineering. • Bacteria have tiny rings of DNA called plasmids. • Plasmids are closed loops of DNA that are separate from the bacterial chromosome and that replicate on their own within the cell.

  18. New genes can be added to an organism’s DNA (cont.). • Recombinant DNA is found naturally in bacteria that take in exogenousDNA, or DNA from a different organism, and add it to their own. • Scientist have adapted what happens in nature to make artificial recombinant DNA.

  19. New genes can be added to an organism’s DNA (cont.). • Steps to making recombinant DNA: • A restriction enzymeis used to cut out the desired gene from a strand of DNA. • Plasmids are cut with the same enzyme. • The plasmid opens, and when the gene is added to the plasmid, their complementary sticky ends are bonded together by a process called ligation.

  20. Genetic engineering produces organisms with new traits. • After a gene is added to a plasmid, the genetically engineered plasmids can be put into bacteria. • The transformed bacteria make many copies of the new gene. • The bacteria with the recombinant plasmid are called transgenic bacterium.

  21. Genetic engineering produces organisms with new traits. • Genetic engineering in plants: • Can create plants with resistance to frost, diseases, and insects. • Genetically modified (GM) crops include potatoes and corn. • Steps to creating a transgenic plant: • A gene is inserted into a plasmid. • The plasmid is inserted bacteria.

  22. Genetic engineering produces organisms with new traits. • After the bacteria infect the plant, the new gene becomes part of the plant’s DNA and is expressed like any other gene.

  23. Genetic engineering produces organisms with new traits. • Genetic engineering in animals: • Much harder to produce than GM plants because animals are more resistant to genetic manipulation. • Steps to producing a transgenic animal: • Get a fertilized egg cell • Foreign DNA is inserted into the nucleus

  24. Genetic engineering produces organisms with new traits. • The egg is implanted back into the female. • Only a small percentage of the genetically manipulated eggs mature normally. • Only a portion of those that develop will be transgenic. • Gene knockout– when a gene has been purposely “turned off”

  25. Benefits of GM Products: • Crops: • Enhanced taste and quality • Reduced maturation time • Increased nutrients, yields, and stress tolerance • Improved resistance to disease, pests, and herbicides • New products and growing techniques

  26. Benefits of GM Products: • Animals: • Increased resistance, productivity, hardiness, and feed efficiency • Better yields of meat, eggs, and milk • Improved animal health and diagnostic methods

  27. Benefits of GM Products: • Environment: • "Friendly" bioherbicides and bioinsecticides • Conservation of soil, water, and energy • Bioprocessing for forestry products • Better natural waste management • More efficient processing

  28. Benefits of GM Products: • Society: • Increased food security for growing populations

  29. Controversies with GM Products: • Safety: • Potential human health impacts, including allergens, transfer of antibiotic resistance markers, unknown effects • Potential environmental impacts, including: unintended transfer of transgenes through cross-pollination, unknown effects on other organisms (e.g., soil microbes), and loss of flora and fauna biodiversity

  30. Controversies with GM Products: • Access and Intellectual Property: • Domination of world food production by a few companies • Increasing dependence on industrialized nations by developing countries • Biopiracy, or foreign exploitation of natural resources

  31. Controversies with GM Products: • 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

  32. Controversies with GM Products: • Labeling: • Not mandatory in some countries (e.g., United States) • Mixing GM crops with non-GM products confounds labeling attempts

  33. Controversies with GM Products: • Society: • New advances may be skewed to interests of rich countries

More Related