1. Gel Electrophoresis
Biotech I

2. Gel Electrophoresis
Definition: the process of separating molecules based on size and charge
Agarose: highly purified agar, heated and dissolved in buffer. Forms a matrix of pores for molecules to travel through.
Smaller molecules travel further
Molecules migrate towards the
positive (red) end of the chamber

3. Gel Electrophoresis Process Make Agarose gel Prepare samples
Thinner gels (0.8%) yield better results for larger DNA
Prepare samples
Restriction enzymes used to cleave at specified sites
Apply samples to gels, apply current
If samples run from positive end they will run off the gel
Stain gels to see bands
Would not be able to see bands if we did not stain

4. Gel Electrophoresis DNA molecules have a negative charge
This allows them to migrate towards the positive end of the chamber
The samples and the electrophoresis chamber use specialized buffers. Using
TAE/TBE buffer helps stabilize the sample
and allows the reaction to occur quicker in
the chamber.
If water were in the chamber instead of TAE/TBE buffer the reaction would take much longer or migration may not occur at all
Stains: ethidium bromide will cause the bands to glow orange under UV light. Fast stain will result in blue bands

5. Uses for Gel Electrophoresis
DNA fingerprinting or profiling
Paternity testing
Crime scene sample analysis
Identification of bacteria and other pathogens
Who is credited with discovering the DNA profiling process?
Alec Jefferies in 1985