Presentation on theme: "DNA Fingerprinting. We share 99.9% of our DNA with each other. That means the 0.1% of our DNA makes us unique. But that is still is over 3,000,000 differences!"— Presentation transcript:
We share 99.9% of our DNA with each other. That means the 0.1% of our DNA makes us unique. But that is still is over 3,000,000 differences! So what if we cut that DNA up with the same restriction enzymes, do you think we would have the same size fragments???
Two Major Steps Of DNA Fingerprinting 1. cut DNA w restriction enzymes Restriction Fragment Length Polymorphism 2. Gel Electrophoresis: Separate fragments from RFLP by... *Size (length) *Electric Charge http://www.lpscience.fatcow.com/jwanamaker/animations/Chrom&Elpho.html
Steps for Gel Electrophoresis 1. Obtain DNA sample 2. Cut DNA with restriction enzymes 3. Make a gel, put into gel box, fill box with buffer Buffer maintains pH and provides ions for current to flow 4. Load DNA into "wells" of gel 5. Turn on electrical charge DNA is negative - moves to positive 6. Turn off power and see how fragments have traveled Shorter pieces travel farther Bands can be viewed with UV light Figure 13.24 Mixture of DNA mol- ecules of different sizes Cathode Restriction fragments Anode Wells Gel Power source (a) Negatively charged DNA molecules will move toward the positive electrode. (b) Shorter molecules are impeded less than longer ones, so they move faster through the gel.