Gel Electrophoresis Biotech I

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

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

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

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