DNA Fingerprinting

DNA Fingerprinting

-Ex: Crime Scene analysis (matching DNA samples)

How it works:

  • -DNA is a string of nucleotides attached together with a sugar-phosphate backbone (sequence of bases vary)
  • -Restriction enzyme: enzyme that breaks DNA sting at particular sequences of bases
  • - results in fragments of DNA of various lengths
  • -Because everyone has slightly different DNA sequences, if you have DNA samples from >1 person and incubate those samples with the same restriction enzyme, you'll get different number and sizes of fragments
  • -After treating DNA samples with restriction enzymes, you can zap it them with electricity through an agarose gel, and this will seperate the DNA fragments by size
  • -Then stain the gel…to see where DNA bands are
  • DNA has a negative electrical charge (btw, histones are positively charged -> why chromatin possible)
  • Add 5microL of loading buffer (blue "LB") to each sample tube.
  • Loaded molecular ladder (DNA cut into known size fragments) and samples into wells.
  • Run gel electrophoresis ~30 minutes at 200Volts on a 1% agarose gel
  • Soak in Ethidium Bromide (.01%) solution in Tris-Acetate-EDTA buffer

Here is a short video that is straight and to the point about this lab. I wish it didn't cut off but I will keep looking for more videos to post!

That's an awesome video!

They didn't change pippets, so it's not very valid, :) but it is a good example.

Change your pipette tips or be struck down by the might of GOOOOOOOOD!

Wow, good example?

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