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Genetic Engineering. Manipulating DNA . I. Nucleic Acids. Nucleic acids are polymers specialized for storage, transmission, and use of genetic information. DNA = deoxyribonucleic acid RNA = ribonucleic acid Monomers : Nucleotides. C. Bases: Pyrimidines —single rings
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Genetic Engineering Manipulating DNA
I. Nucleic Acids • Nucleic acids are polymers specialized for storage, transmission, and use of genetic information. • DNA= deoxyribonucleic acid • RNA = ribonucleic acid • Monomers: Nucleotides
C. Bases: Pyrimidines—single rings Purines—double rings D. Sugars: DNA contains deoxyribose RNA contains ribose
E. Complementary base pairing: adenine and thymine always pair (A-T) cytosine and guanine always pair (C-G)
F. Model building is the assembly of 3-D models of possible molecular structures. • Francis Crick and James Watson used model building and combined all the knowledge of DNA to determine its structure. • Franklin’s X-ray crystallography convinced them the molecule was helical. • Modeling also showed that DNA strands are anti-parallel.
G. Organization • Nucleotides make up DNA (3 billion) • DNA forms genes (20,000) • Genes make up chromosomes (46 in humans) • Found in the nucleus
II. Primitive Methods of genetic engineering A. Selective Breeding- selecting which organisms reproduce based on desirable traits B. Hybridization- Breeding similar organisms with desirable traits C. Inbreeding- keeping a pure line of desirable traits
D. Manipulating DNA 1. Extract- through chemical means 2. Cut or cleave- using restriction enzymes • Enzymes seek out specific DNA sequences and cut DNA at that spot
E. Polymerase chain reaction 1. Used to copy specific gene sequences • three basic steps • denaturation • annealing of primers • primer extension
F. Separate- using gel electrophoresis 1. A gel is made using agarose 2. The gel has pores of different sizes running throughout it 3. DNA samples are cleaved with restriction enzymes and placed in wells at 1 side 4. An opposite charge is generated on the opposite side 5. The DNA fragments are pulled through to different lengths depending on size 6. The fragments are dyed and “fingerprints are left”
7. Restriction fragment length polymorphisms (RFLP’s) can be used to identify a particular individual
III. Transgenic Organisms (Chimeras) A. Organisms that contain spliced in genes from other organisms B. Has been done in animals and is commonly done in plants C. Transforming bacteria has become one of the biggest scientific breakthroughs in yrs
D. Transforming Bacteria 1. Bacteria contain a circular piece of DNA called a PLASMID 2. The plasmid is cleaved open 3. The transgenic gene is cleaved from the host 4. The host gene is spliced into the plasmid 5. The bacteria take in the plasmid
6. Bacteria Begin to produce the protein 7. Bacteria reproduce asexually, creating billions 8. Used for insulin, growth hormone, cleaning oil spills
A Transgenic Cell Can Produce Large Amounts of the Transgene’s Protein Product
IV. Cloning • Creating a new genetically identical organism • Process 1. Obtain an unfertilized egg cell and a somatic cell 2. Remove the nuclei from the cells 3. Insert the somatic nucleus into the egg cell 4. Implant into uterus
C. Practical applications for cloning: • Expansion of numbers of valuable animals • Preservation of endangered species • Preservation of pets
V. Biotechnology A. Medical applications 1. Pharmaceuticals • introduction of protein-encoding genes 2. Gene therapy • add working copies of single defective gene 3. Piggyback vaccines • produce subunit vaccines against viruses • herpes • hepatitis • DNA vaccine • cellular immune response
B. Agricultural Applications 1. Insect resistance • insert genes encoding proteins harmful to insects 2. Produce genetically modified plants with traits benefiting consumers • iron deficiency in developing countries • transgenic rice • increasing milk production • bovine somatotropin
VI. Gene Sequencing • The human genome project • Completed in 2003 • Complete global effort • The entire human genome has now been sequenced • A complete human genome can now be sequenced for under $1000 • 23 and me • Decode me • The sequence can determine likelihood of potential disorders or diseases • Is not however written in stone • Epigenetics and the environment play a major role
VII. Risk and Regulation A. Questions • How do we measure the potential risks of genetically modified crops ? • Is eating genetically modified food dangerous ? • Are genetically modified crops harmful to the environment ? • Should we label genetically modified foods ? • Should human cloning be legal? • Designer babies • Can people be discriminated against based on their genome? • Jobs • Life Insurance • Health Insurance