gel electrophoresis

Cards (4)

  • stages
    1. fragments of DNA cut with restriction enzyme and dyed with florescent tags
    2. fragments placed in wells of agarose gel
    3. current applied to gel- DNA is negative to moves towards the anode, fragments of different sizes move at different speeds according to mass= appears in bands
    4. nylon filter placed on top- draws solution containing DNA fragments to the filter, fragments appear as blots
  • satellites
    • introns= non coding regions of DNA
    • exons=coding regions of DNA
    • gives rise to genetic variation between organisms
    • introns consist of many repeating base sequences- short tandem repeats-in sections known as satellites
  • analysing gel electrophoresis
    produces patterns of bands
    • restriction enzymes cut DNA at specific locations in DNA, always cut between sections of variable number repeats
    • different people have a different number of repeats in there VNTR regions so fragments differ in lengths
    diff individuals will have diff lengths of DNA fragments so different pattern of banding- unique to individual
  • DNA profiling uses
    1. determine genetic relationship- if bands match between individuals likely they share DNA, more bands that match=greater genetic similarity
    2. helpful in captive breeding programmes-crossbreeding individuals genetically the most different for more variation, can prevent inbreeding of closely related- inbreeding= small gene pool reducing ability to adapt to change