Presentation on theme: "Biotechniques. Gel electrophoresis Separates molecules according to size and charge. Different sized segments of DNA cut by restriction enzymes Segments."— Presentation transcript:
Gel electrophoresis Separates molecules according to size and charge. Different sized segments of DNA cut by restriction enzymes Segments marked with fluorescent or radioactive dyes Show up as bands on the gel.
Precipitation & Centrifugation DNA fragments form solid pellet at bottom of tube.
Gel electrophoresis machines can sequence up to 600 bases at a time
Loading the Samples Known control DNA sample is applied to the first lane Problems with the control sequence all results invalid.
Gel electrophoresis Carried out on agarose or acrylamide gel sandwiched between two plates. Smaller fragments moving further in the same time than larger fragments. -ve +ve
Buffer solution Cathode Anode Gel Electric current Buffer Sample Samples placed in wells with buffer
Visualized by applying dyes or radio-labeled probes. Analyzing DNA DNA markers: DNA molecules with known molecular weights.
Bands visualized under UV light
Gel electrophoresis #docid= (electrophoresis, 1 min, good short intro) #docid= #docid= (Woolfe, electrophoresis, 10 min) #docid= # (gel electrophoresis, 7 min – bit slow) #