GEL ELECTROPHORESIS

• measures the length of DNA

• types of blotting techniques

  • southern: DNA

  • northern: RNA

  • western: Protein

• gel - filter the DNA

• electrophoresis - how DNA strands push through the gel (from negative charge (DNA samples located) → positive charge)

• shorter strand - far from the origin

• longer strand - near the origin

Materials

1. agarose

2. flask

3. gel mold

4. gel comb

5. buffer

6. microwave

Steps

1. make the gel

   1. add agarose to flask

   2. add buffer to the flask

      • salt water solution - will let electrical charges flow through the gel

   3. heat the mixture in the microwave until agarose melt to the buffer

   4. put into the mold

   5. place the comb to make notches

   6. let the gel cool (~30 mins)

   7. remove the comb

2. set up the gel apparatus

   1. pour the buffer into the electrophoresis box

   2. place the gel into the electrophoresis box (barely submerged)

3. load the DNA sample into the gel

   1. suck loading buffer

      • contains dye for visualization

      • makes the DNA thicker so it will not float

   2. place to the sample

   3. place the sample to the gel and the standard

4. Hook up the electrical current and run the gel

   • repelled by the negative charge, DNA moves thru the gel toward positive charge

     • short DNA - moves faster → far from the origin

     • long DNA - moves slower → near the origin

5. stain the gel and analyze the results

   1. ethidium bromide - staining solution

      • binds to DNA and shows up under fluorescent light

   2. takes about 1 hour

   3. place on UV detector