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Published byGarey Norman Modified over 9 years ago
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Control & Manipulation of Genes
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Before Transcription Access Acetylation loosens grip of histone, allowing access of polymerase to DNA Methylation of an allele blocks that gene’s affect How transcribed Gene sequences rearranged or multiplied, generate large amounts of gene product
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Transcription Processing mRNA cannot pass out of nucleus without transport protein Some proteins can block translation from starting Translation Control Affect ribosome components (no rRNA, no translation) Control speed of breaking down mRNA (how many times it can be reused)
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X Chromosome Inactivation Females XX One X chromosome is 75% “shut down” Barr body—condensed X chromosome Random
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Operon—arrangement of promoter and operators that control access to a gene Lac operon in E. coli cells E. coli normally doesn’t use lactose (milk sugar) Lac operon binds to gene that would allow use of lactose, prevents it’s transcription When glucose is scarce but lactose present, activator is synthesized Activator then prevents lac operon from functioning, allowing lactose to be used Inhibition can be reversed
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Recombinant DNA—any DNA molecule consisting of base sequences from two or more organisms of the same or different species. Able to combine genetic sequence of different species Restriction enzymes Plasmids & cloning vectors
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A restriction enzyme is added to a solution with DNA Enzyme “cuts” DNA at a specific place Can fuse with DNA molecule “cut” with same enzyme
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Bacteria have two forms of DNA One chromosome, a single circular DNA strand Plasmids—small circles of “extra” DNA with only a few genes Bacteria divide rapidly, providing many new organisms in a short period of time.
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In nature, bacteria can share characteristics through plasmids Antibiotic resistance
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With restriction enzymes, can splice DNA into plasmid Plasmid taken into bacteria cells
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“Donor” gene is used by bacteria, produces product of gene Is now part of bacteria’s genetic code, is passed on during division
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Uses Laboratory studies of specific genes Produce products quickly & cheaply Insluin Antibiotics Vaccines Animal diseases HIV Ebola
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Polymerase Chain Reaction (PCR)—method to reproduce fragments of DNA millions or billions of time Primer—short stretch of synthetic, single- stranded DNA
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Primers are added to solution with DNA fragments and polymerase Solution is heated, denaturing and “opening” DNA Solution is cooled Primers attach to matching base pairs during cooling Polymerase starts at primer, synthesizes DNA chain Process is repeated
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Each “cycle” results in exponential growth Quickly grow a segment of DNA
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Uses Forensics Diagnostics (viral & bacterial diseases) Paternity or relationship testing Historical analysis Mummies, mammoths, etc.
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DNA is mixed with certain compounds in a solution The solution is placed into a gelatinous substance Electrical charge is carried along the gel The DNA separates along the gel in a pattern based on the structure and weight of the individual genes
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Everyone’s DNA is unique to them Base-pair patterns different between people PCR & electrophoresis to find & analyze DNA 1 in 3,000,000,000,000 chance of unrelated people having identical DNA
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1988—National Institutes of Health combined previously begun research into one project 2003—Human genome officially completed Almost 20,000 confirmed genes Over 2,000 possible genes Don’t know what all of these genes do! Much of human genome DOESN’T code for proteins Many might regulate expression of other genes…. “Master Control” genes
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Study diseases & disorders Be able to predict and detect disease Gene therapy—transfer one or more normal or modified genes into a person’s body cells Correct genetic defect Boost resistance to disease Imperfect at this time
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Bacteria Insulin Blood-clotting factors Hemoglobin Vaccines Environmental clean-up Oil spills Pollutants Radioactive waste
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Plants Drought resistance Disease resistance Herbicide resistance Soil tolerance Greater yield Better nutrition
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Animals Medical research Mice susceptible to human diseases Disease resistance Environmental resistance Featherless chickens Medical proteins Cattle—human collagen (cartilage, bone, skin repair) Better nutrition Low-fat pigs
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