Genetic Engineering by a61N7e

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									  Genetic Engineering

DNA Technology and Techniques
             Background Info
• Bacterial
  Chromosome:
  – 2.2 million base pairs
  – 1200 genes
  – Loops of DNA
• Plasmid:
  – Short loops of DNA
  – 2-30 genes
  – Are passed during
    conjugation
        Restriction Enzymes
• Restriction Enzymes: Bacterial proteins
  used to cut DNA into the pieces scientists
  want to use.
  – They recognize certain nucleotides and cut
    there.
  – Many different types
          Restriction Enzymes
• The DNA cut with a
  certain restriction
  enzyme will “stick” to
  any other piece of
  DNA that is cut with
  the same restriction
  enzyme
   – even if they come from
     different organisms.
           Why Use Bacteria?
•   Simple DNA
•   Reproduce Quickly
•   Reproduce Asexually
•   “operate” on it easily
•   No one cares if we kill some bacteria
            Combining DNA
• Recombinant DNA: combination of DNA
  from two sources
  – Human and Bacterial
    • Insulin gene spliced into plasmid
  – Mouse and Human
  – Bacterial and Viral
  – Firefly and Plant
      How Can This Help Us?
• Cure or Treat Diseases
• Genetically Modify our Foods
  – Taste, shelf life, nutritional value
• Clone Organs
• Better Understand Genetics
        DNA and Forensics
• DNA fingerprint: pattern of bands from
  someone’s DNA
  – Different bands can be compared
• Gel Electrophoresis: separates
  nucleotides to create a DNA fingerprint
    Gel Electrophoresis Process
•   Get the DNA
•   Cut it using restriction enzymes
•   DNA is “loaded” into wells in a gel
•   Each lane of DNA is cut using a different
    restriction enzyme
•   Current is turned on
•   DNA migrates towards “+” electrode
•   Short pieces of DNA migrate faster than larger
    pieces do
•   Pattern of bands is seen
•   Bands from Suspect can be Compared With
    Crime Scene DNA
Compare Plant Varieties
  What if there isn’t a big enough
              sample?
• Then we use a method called PCR
  – (Polymerase chain reaction)
  – Quickly makes copies of the DNA

								
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