Gel electrophoresis power point may 23Presentation Transcript
What is Gel Electrophoresis? Gel electrophoresis is a process that separates fragments of DNA based on their sizes.
Step 1 Place DNA into tubes DNA can come from tissue orbody fluid, such ascheek cells, blood, skin, and hair.
Step 2 Polymerase Chain Reaction The polymerase chain reaction uses a machine called a thermocycler to quickly copy a piece of DNA. Continue these three steps 30 to 40 times to get lots of copies of DNA.
Step 3 Place restriction enzymes into DNA The restriction enzymes cut the DNA into different sizes according to it’s sequence.
Step 4 Dye DNA and place into gel The gel is made with The gel is made out of wells at one end so agarose, which is similar that the DNA can be to jello. loaded into the gel.
Step 5 Run electric current through gel DNA is negativelycharged so it will move towards the positivelycharged end of the gel.
Step 6 Smaller pieces of DNA travel farther than Larger pieces of DNA End result!
Gel Electrophoresis is used to... Solve criminal cases Solve paternity cases Diagnose genetic diseases Determine genetic kinship among species
Pros Cons Easy to do Expensive DNA does not get ruined in the Time consuming process Uses hazardous material You only need a small amount of DNA to start with DNA can be detected no matter what size it is
Tommie Lee Andrews Case Tommie Lee Andrews was the first person in the U.Sto be convicted with the help of DNA fingerprintingevidence. Andrews was convicted for strangling two teenagegirls. The judge in Andrews’ first trial did not allow the DNAfingerprinting evidence, although Andrews ended up havinga second trial. The judge in his second trial did allow theDNA fingerprinting, which proved Andrews guilty and hewas convicted in 1987. This is just one of many cases thatDNA fingerprinting/gel electrophoresis has been used tosolve a crime.