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Genetic Engineering

Genetic Engineering. Selective breeding – controlled breeding for desired characteristics; takes advantage of naturally occurring genetic variation – Fig. 13 – 1 What are some organisms that are good examples of selective breeding?

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Genetic Engineering

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  1. Genetic Engineering

  2. Selective breeding – controlled breeding for desired characteristics; takes advantage of naturally occurring genetic variation – Fig. 13 – 1 What are some organisms that are good examples of selective breeding? 1. hybridization – breeding technique that involves crossing dissimilar individuals to bring together the best traits of both organisms 2. inbreeding – mating between organisms that are genetically similar: promotes preservation of desired characteristics; decreases genetic variation Genetic Engineering

  3. Hybridization X

  4. Inbreeding

  5. Increasing genetic variation can be accomplished by inducing mutations 1. Bacteria – radiation or chemicals can cause “beneficial mutations” – Fig. 13-3 2. Plants – chemicals that prevent chromosomal separation lead to polyploidy (What advantages do these plants have?) 3. Induced mutations can also be used to study the function of proteins Genetic Engineering

  6. How do scientists change/manipulate DNA? 1. DNA extraction – remove DNA from the cell 2. DNA cutting – restriction enzymes “cut” DNA at very specific nucleotide sequences Fig. 13-5 Manipulating DNA Restriction Enzyme http://www.youtube.com/watch?v=yc-s-WojU5Y&feature=related

  7. How do scientists change/manipulate DNA? 3. DNA separating – gel electrophoresis uses an electrical current to separate fragments of DNA based on size – Fig. 13-6 Manipulating DNA Gel Electrophoresis http://www.sumanasinc.com/webcontent/animations/content/gelelectrophoresis.html

  8. Reading the sequence allows the study of specific genes – Fig. 13 -7 (Sanger Sequence) 1. Start with a single strand of DNA with unknown sequence 2. Mix this strand with DNA polymerase and a lot of nucleotides; some of the nucleotides are “tagged” with dye 3. each time a “tagged” nucleotide is added replication stops 4. Using gel electrophoresis complementary DNA strand is “read” Using the DNA sequence

  9. Sanger Sequencing Videos http://www.youtube.com/watch?v=aPN8LP4YxPo&feature=related http://www.youtube.com/watch?v=6ldtdWjDwes&feature=related Using the DNA sequence

  10. PCR – Polymerase Chain Reaction A technique by which any segment of DNA can be quickly amplified (copied many times) – Fig. 13-8 1. DNA is separated and added to a mixture of nucleotides and enzymes 2. New complementary strands are made 3. Cycle is repeated many times

  11. PCR

  12. PCR http://www.youtube.com/watch?v=JRAA4C2OPwg&feature=related PCR Animation PCR Song http://www.youtube.com/watch?v=x5yPkxCLads

  13. Cell Transformation – taking up foreign DNA Some bacteria can take up naked DNA from the surroundings. Plasmid – a small, circular, self-replicating DNA molecule separate from the bacterial chromosome Assimilated foreign DNA is taken up by the plasmid Offspring of the recipient bacterium will carry a new combination of genes Genetic marker – a gene that produces a known protein that can be used to “mark” bacteria that have taken up foreign DNA

  14. Cell Transformation

  15. Cell Transformation Plant Transformation – Fig. 13-10 Plasmids that normally infect plant cells can be used as carriers of foreign DNA Whatever gene is taken up is then expressed by the plant cell What are some advantages and disadvantages of this technology?

  16. The bacterium can be used to introduce foreign DNA into plant cells. If the transformation is successful, the DNA will be integrated into one of the cell’s chromosomes. Cell Transformation

  17. Cell Transformation Animal Transformation – Fig. 13-11 Eggs cells are large enough to take up foreign DNA DNA is inserted manually and enzymes normally present in the cell to repair DNA help to insert the foreign DNA Technique can be sued to study specific functions of a gene

  18. Applications of Genetic Engineering Transgenic organisms contain genes from another species; possible because of the universal nature of the genetic code – Fig. 13-12 Microorganisms – easy to grow, divide rapidly, can be used to produce human proteins Animals can be used to improve food supply, or to study effect of human diseases Plants – genes can be implanted that provide plants with natural insecticides, or resistance to various chemicals

  19. This transgenic tobacco plant, which glows in the dark, was grown from a tobacco cell transformed with the firefly luciferase gene. The plant illustrates how DNA from one organism contains information that can specify traits in another organism. Transgeneic Organisms

  20. Applications of Genetic Engineering Cloning – A clone is a lineage of genetically identical individuals or cells Basic cloning technique – Fig. 13-13 KNOW!!!

  21. In early 1997, Dolly made headlines as the first clone of an adult mammal. Transgenic Organisms

  22. Why did Dolly not look like her foster mother? Transgenic Organisms

  23. The adult sheep is Dolly. The lamb is Dolly’s first offspring., called Bonnie. The fact that dolly was cloned did ot affect her ability to produce a live offspring. Why might it be important for cloned animals to be able to reproduce? Transgenic Organisms

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